CN114071595A

CN114071595A - Communication method and communication device

Info

Publication number: CN114071595A
Application number: CN202010762533.9A
Authority: CN
Inventors: 李卓明
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-07-31
Filing date: 2020-07-31
Publication date: 2022-02-18
Also published as: WO2022022082A1

Abstract

The present application provides a communication method and a communication device. The method includes: the first access network device determines that the signal quality of the terminal device in the source cell is lower than a preset threshold; the first access network device determines the target cell and controls the terminal device to switch to the target cell. Or, the first access network device determines that the first radio resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session that the terminal device requests to establish or request to activate; the first access network device determines The target cell is controlled, and the terminal equipment is controlled to switch to the target cell; the second radio resource of the target cell supports the first network slice. Therefore, when the signal quality of the terminal device in the source cell is not good, or the first radio resource of the source cell does not support the network slice corresponding to the session requested by the terminal device to establish or activate, the first access network device can timely provide The terminal device determines the target cell to improve user experience.

Description

Communication method and communication device

Technical Field

The present application relates to the field of wireless communication, and more particularly, to a communication method and a communication apparatus.

Background

Currently, a technology is known in which a terminal device may perform cell or frequency reselection based on a radio access technology frequency selection priority (RFSP) index allocated by a core network. One RFSP index value may be associated to a set of cell/band camping or reselection parameters. In one implementation, the access network device may query a cell/frequency camping or reselection parameter specific to the terminal device according to the authorized RFSP index, and then issue the cell/frequency camping or reselection parameter to the terminal device. After the terminal equipment enters an idle state, the frequency band with high priority can be selected for access according to the parameters.

However, the terminal device needs to wait until the current service is finished and enters an idle state, and then performs cell/frequency band reselection according to the radio parameters corresponding to the RFSP index. When the signal quality of the current cell is not good, or the network slice corresponding to the session requested to be established or requested to be activated is not supported by the radio resource of the currently accessed cell, the terminal device cannot be switched to the appropriate cell in time, which may cause the communication quality of the current session of the terminal device to be reduced, or the session requested to be established or requested to be activated by the terminal device cannot be responded in time, and the user experience is not good.

Disclosure of Invention

The application provides a communication method and a communication device, which are used for controlling terminal equipment to be switched to a proper cell in time, so that the communication quality of the terminal equipment can be improved in a short time, or a session which is requested to be established or activated is requested to be responded in time, and the user experience is improved.

The methods of the first to third aspects provided below may be performed by the first access network device, for example, or may also be performed by a component (e.g., a circuit, a chip, or a chip system, etc.) configured in the first access network device. This is not a limitation of the present application. The method provided by the present application is described below with the first access network device as the executing subject for ease of understanding and explanation only.

In a first aspect, a communication method is provided, and the method includes: the first access network equipment determines that the signal quality of the terminal equipment in a source cell is lower than a preset threshold, wherein the source cell is a cell served by the first access network equipment; the first access network equipment determines a target cell from at least one adjacent cell according to a first network slice corresponding to a first session activated in a source cell by the terminal equipment and network slices respectively supported by the at least one adjacent cell of the source cell, wherein the target cell supports the first network slice; the first access network equipment controls the terminal equipment to be switched to the target cell.

Based on the above technical solution, when the signal quality of the terminal device in the source cell is not good, the first access network device serving the source cell may determine the target cell for the terminal device according to the network slice corresponding to the session activated by the terminal device in the source cell, the network slices respectively supported by at least one neighboring cell, and the frequency ranges corresponding to the network slices, and control the terminal device to switch to the target cell. Therefore, the terminal equipment can be switched to the target cell with better signal quality in time under the condition that the signal quality is poor and the switchable target cell exists, so that measures can be taken in time under the condition that the communication quality is poor, and the terminal equipment does not need to enter an idle state to reselect the cell after finishing the current service. Therefore, the communication quality of the terminal equipment can be improved in a short time, and the improvement of user experience is facilitated.

In order to obtain better signal quality, the target cell determined by the first access network device for the terminal device supports the first network slice on one hand, and the signal quality meets a preset threshold on the other hand.

With reference to the first aspect, in some possible implementations of the first aspect, the target cell is another cell than the source cell among a plurality of cells served by the first access network device.

That is, the terminal device can switch to the target cell with better signal quality as long as it performs the intra-site handover.

With reference to the first aspect, in some possible implementations of the first aspect, the target cell is a cell served by the second access network device.

Here, the second access network device is a different access network device than the first access network device. That is, the source cell is different station from the target cell. The terminal device needs to switch the access network device. That is, the terminal device needs to perform cross-site handover.

If the cell served by the first access network device only includes the source cell of the terminal device, or if the first access network device does not find a suitable cell among the intra-station adjacent cells as the target cell, the target cell may be found among the extra-station adjacent cells. It should be understood that if there are multiple out-of-station neighboring cells, the multiple out-of-station neighboring cells may be cells served by one or more access network devices. The one or more access network devices include a second access network device.

In one implementation, the first access network device may preferentially search for a target cell in an adjacent cell served by the first access network device, and then search for a target cell in an adjacent cell served by another access network device, so as to avoid a complex procedure for switching the access network device.

Optionally, the method further comprises: the first access network equipment determines a wireless measurement parameter according to a first network slice, network slices respectively supported by the at least one adjacent cell and wireless resources corresponding to the supported network slices; the first access network equipment sends wireless measurement parameters to the terminal equipment, and the wireless measurement parameters are used for the terminal equipment to measure the signal quality of the adjacent cells; wherein the measurement of the signal quality of the neighbouring cell by the terminal device is used for the determination of the target cell.

If the first access network wants to find the target cell from the neighboring cells served by other access network devices, the target cell may be further selected according to the signal quality of the neighboring cells outside each station. Therefore, the first access network device may determine the radio measurement parameter according to the first network slice, the network slices supported by the neighboring cells, and the radio resource corresponding to each network slice. The terminal device may measure the signal quality of the neighboring cell based on the wireless measurement parameter, so that the first access network device determines the target cell according to the measurement result.

Optionally, the method further comprises: the first access network equipment sends a request message to the second access network equipment, wherein the request message carries the identification information of the first session and the identification information of the first network slice; receiving, by a first access network device, Radio Resource Control (RRC) parameters for handover from a second access network device; the first access network device sends the RRC parameter to the terminal device.

After determining the target cell for the terminal device, the first access network device may send a request message to a second access network device serving the target cell to request to acquire an RRC parameter for handover. In one possible design, the request message is a handover request (handover request) message. Correspondingly, the second access network device may send the RRC parameter to the first access network device through a handover request acknowledgement (handover request ACK) message. The RRC parameter may be carried in an RRC message container in the handover request confirm message, so that the first access network device passes the RRC parameter through to the terminal device.

In a second aspect, a communication method is provided, including: the method comprises the steps that first access network equipment determines that first wireless resources accessed by terminal equipment in a source cell do not support a first network slice corresponding to a first session requested to be established or activated by the terminal equipment, and the source cell is a cell served by the first access network equipment; the first access network equipment determines a target cell, and second wireless resources of the target cell support a first network slice; and the first access network equipment controls the terminal equipment to be switched to the target cell.

Based on the above technical solution, when the first session requested to be established or requested to be activated by the terminal device is not supported by the radio resource of the source cell, the first access network device serving the source cell may determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slices respectively supported by at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can timely switch the terminal device to the target cell under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell and a switchable target cell exists, and the terminal device does not need to enter an idle state for cell reselection after finishing the current service. Therefore, the session request of the terminal equipment can be responded in time, the first session is activated in a short time, and the user experience is improved.

Optionally, the second radio resource further supports a network slice corresponding to a second session of the terminal device, where the second session includes an activated session or a deactivated session.

That is, the target cell supports not only the first network slice but also other network slices, for example, a network slice corresponding to an activated session or a deactivated session, so as to avoid service interruption of the activated or deactivated session due to cell handover or cell re-handover due to cell handover failure.

With reference to the second aspect, in some possible implementation manners of the second aspect, the determining, by the first access network device, the target cell includes: the first access network device determines a target frequency range and determines a target cell based on the target frequency range.

Wherein the target frequency range is a frequency range supporting the first network slice. The target frequency range may be selected first with the target frequency range indicated by the first radio resource and second with the other frequency ranges.

Optionally, the determining, by the first access network device, the target frequency range includes: the first access network device determines a target frequency range according to the network slice allowing the terminal device to access, the first network slice and a frequency range corresponding to the first network slice.

It should be understood that the network slice that the terminal device is allowed to access may be determined according to the network slice requested by the terminal device, the network slice subscribed to by the terminal device, and the network slices supported by the tracking area or the registration area in which the terminal device is located. The network slice signed by the terminal device may be obtained by the access and mobility management network elements from the unified data management network element. Thus, the network slice to which the terminal device is allowed to access may be determined by the access and mobility management network element and inform the first access network device in order for the first access network device to determine the target frequency range.

Optionally, the determining, by the first access network device, the target frequency range includes determining, by the first access network device, the target frequency range according to the network slice requested by the terminal device, the network slice that can be used by the terminal device according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, and the frequency ranges of the first network slice and the first network slice.

The network slice that can be used by the terminal device according to the subscription may be, for example, a core network device such as an access and mobility management network element that notifies the first access network device.

When the terminal device is in the home network, the network slice that the terminal device can use according to the subscription may refer to the network slice subscribed by the terminal device; when the terminal device is visiting the network, the network slice that the terminal device can use according to the subscription may refer to a network slice of the visited network corresponding to the network slice subscribed by the terminal device.

Thus, the two implementations listed above for determining the target frequency range are alternative.

With reference to the second aspect, in some possible implementation manners of the second aspect, the determining, by the first access network device, a target cell includes: the first access network device determines a target cell from among intra-site neighboring cells supporting the target frequency range, the intra-site neighboring cells being other than the source cell among a plurality of cells served by the first access network device.

Optionally, the controlling, by the first access network device, the terminal device to switch to the target cell includes: the first access network device sends a Radio Resource Management (RRM) configuration message to the terminal device, where the RRM configuration message is used to control the terminal device to switch to the target cell.

That is, the first access network device may look for a target cell among the intra-station neighbor cells served by the first access network device based on a predetermined target frequency range. If the first access network device finds the target cell in the adjacent cells in the station, the terminal device can switch to the target cell supporting the first network slice as long as the terminal device executes the intra-station switching.

With reference to the second aspect, in some possible implementation manners of the second aspect, the determining, by the first access network device, a target cell includes: the first access network device identifies a target cell from the out-of-station neighboring cells that support the target frequency range, the out-of-station neighboring cells being cells of the neighboring cells of the source cell other than the cell served by the first access network device.

Optionally, the determining, by the first access network device, the target cell from the out-of-station neighboring cells supporting the target frequency range specifically includes: the first access network equipment determines whether a first cell supporting a target frequency range exists in an out-of-station adjacent cell of the source cell; the method comprises the steps that a first access network device determines whether a first cell supports first network slicing under the condition that the first cell exists; the first access network device determines that the first cell is a target cell under the condition that the first cell supports the first network slice.

If the cell served by the first access network device only includes the source cell of the terminal device, or if the first access network device does not find a suitable cell in the intra-station adjacent cells as the target cell, the first access network device may directly find the target cell in the extra-station adjacent cells. It should be understood that if there are multiple out-of-station neighboring cells, the multiple out-of-station neighboring cells may be cells served by one or more access network devices. The one or more access network devices include a second access network device.

In one implementation, the first access network device may preferentially search for a target cell in neighboring cells served by the first access network device and then search for a target cell in neighboring cells served by other access network devices based on the target frequency range, so as to avoid a complex procedure for switching the access network devices.

In addition, the target frequency range may preferentially select the frequency range indicated by the first radio resource. That is, the first access network device may preferentially search for a target cell in an adjacent cell served by the first access network device and then search for a target cell in an adjacent cell served by another access network device based on the first frequency range; and secondly, based on the second frequency range, searching a target cell in the adjacent cells served by the first access network equipment, and searching the target cell in the adjacent cells served by other access network equipment. In any step of the above process, as long as the first access network device finds the target cell, the subsequent step of finding the target cell may not be performed.

Optionally, the method further comprises: the first access network equipment determines wireless measurement parameters according to the target frequency range; the first access network equipment sends the wireless measurement parameter to the terminal equipment, and the wireless measurement parameter is used for the terminal equipment to measure the signal quality of the adjacent cell; the measurement of the signal quality of the neighbouring cells by the terminal device is used for the determination of the target cell.

If the first access network wants to find the target cell from the neighboring cells served by other access network devices, the target cell may be further selected according to the signal quality of the neighboring cells outside each station. Therefore, the first access network device may determine the radio measurement parameter according to the first network slice, the target frequency range, the network slices respectively supported by the at least one neighboring cell, and the radio resource corresponding to each network slice. The terminal device may measure the signal quality of the neighboring cell based on the wireless measurement parameter, so that the first access network device determines the target cell according to the measurement result.

Optionally, the method further comprises: the first access network equipment sends a request message to second access network equipment serving a target cell, wherein the request message carries identification information of a first session and identification information of a first network slice; the first access network device receiving an RRC parameter for handover from the second access network device; the first access network device sends the RRC parameter to the terminal device.

After determining the target cell for the terminal device, the first access network device may send a request message to a second access network device serving the target cell to request to acquire an RRC parameter for handover. In one possible design, the request message is a handover request message. Correspondingly, the second access network device may send the RRC parameter to the first access network device through the handover request acknowledgement message. The RRC parameter may be carried in an RRC message container in the handover request confirm message, so that the first access network device passes the RRC parameter through to the terminal device.

With reference to the first aspect or the second aspect, the RRC parameter is associated with a radio resource corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device. Wherein the network slice supported by the second access network device refers to a network slice supported by at least one cell served by the second access network device.

The RRC parameter may be determined by the second access network device according to a first network slice corresponding to the first session to be handed in, where the first network slice is determined by a radio resource corresponding to a cell served by the second access network device, so that the second access network device may determine to which cell to handover.

In a third aspect, a communication method is provided, including: the first access network equipment determines that a first wireless resource accessed by the terminal equipment in a source cell does not support a first network slice of a first session requested to be established or activated by the terminal equipment, and the source cell is a cell served by the first access network equipment; the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device. The first access network device releases the RRC connection with the terminal device and the currently active session is subsequently deactivated.

Based on the above technical solution, the first access network device may actively release the RRC connection with the terminal device when the first radio resource accessed by the terminal device does not support the first network slice of the first session requested to be established or requested to be activated, so that the terminal device may quickly enter an idle state to initiate cell reselection. And the idle state is not required to be entered after the current service is finished. Therefore, the terminal device can perform cell reselection in time without waiting for the terminal device to enter an idle state for cell reselection after completing the current service, under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell. Therefore, the session request of the terminal equipment can be responded in time, the first session is activated in a short time, and the user experience is improved.

With reference to the third aspect, in some possible implementation manners of the third aspect, the method further includes: the first access network equipment determines a target frequency range according to the network slice allowing access and the frequency range corresponding to the first network slice; or, the first access network device determines a target frequency range according to a network slice requested by the terminal device, a network slice which can be used by the terminal device according to the subscription, a network slice supported by a tracking area or a support area where the terminal device is located, the first network slice and a frequency range corresponding to the first network slice; the first access network equipment determines a wireless parameter according to the target frequency range, the network slices respectively supported by at least one adjacent cell and wireless resources corresponding to the supported network slices, wherein the wireless parameter is used for cell reselection of the terminal equipment; and the first access network equipment sends the wireless parameters to the terminal equipment.

In order to facilitate the terminal device to quickly find a suitable cell for access, the first access network device may send the wireless parameter to the terminal device, so that the terminal device performs cell reselection based on the wireless parameter, thereby facilitating the terminal device to quickly select a cell for re-access.

With reference to the second aspect or the third aspect, in some possible implementations, the method further includes: the first access network device receives a message from the terminal device requesting establishment of or activation of the first session.

The terminal device requesting establishment or requesting activation of the first session in the source cell may occur in different scenarios.

The first possible scenario is that the terminal device may be a terminal device that accesses the network after being powered on, or may be a terminal device that initiates a registration request when moving to a new tracking area that does not belong to the original registration area, or may be a terminal device that periodically updates the network with the registration.

In this case, the first access network device receives a message requesting establishment of the first session or requesting activation of the first session from the terminal device, and includes: the first access network equipment receives a registration request message from the terminal equipment, wherein the registration request message carries identification information of a first session which is requested to be established or activated.

A second possible scenario is that the terminal device has established one or more sessions in the source cell served by the first access network device, but the one or more sessions are in a deactivated state, the terminal device and the first access network device each retain context for the one or more sessions for which user plane connections are not active. Or, the terminal device desires to establish one or more new sessions in the source cell.

In this case, the first access network device receives a message requesting establishment of the first session or requesting activation of the first session from the terminal device, and includes: the first access network equipment receives a session request message from the terminal equipment, wherein the session request message carries identification information of a first session which is requested to be established or activated.

A third possible scenario is that the terminal device is in an RRC connected state with the first access network device. The terminal device expects to establish one or more new sessions or activate one or more sessions in the source cell.

In this case, the first access network device receives a message requesting establishment of the first session or requesting activation of the first session from the terminal device, and includes: the method comprises the steps that a first access network device receives a session establishment request message from a terminal device, wherein the session establishment request message carries identification information of a first session which is requested to be established, or the session establishment request message carries identification information of a first network slice corresponding to the first session; or, the first access network device receives a session activation request message from the terminal device, where the session activation request message carries identification information of a first session requested to be activated, or the session activation request message carries identification information of a first network slice corresponding to the first session.

It should be understood that the several possibilities listed above are merely exemplary for facilitating an understanding of the methods provided by the embodiments of the present application and should not be construed as limiting the present application in any way.

In a fourth aspect, a communication device is provided, which includes various means or units for performing the method of any one of the possible implementations of the first to third aspects.

In a fifth aspect, a communications apparatus is provided that includes a processor. The processor is coupled to the memory and is operable to execute instructions or data in the memory to implement the method of any one of the possible implementations of the first to third aspects. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, the processor being coupled to the communication interface.

In one implementation, the communication device is an access network apparatus, such as the first access network apparatus in the first to third aspects. When the communication device is an access network device, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in the access network equipment. The access network device may for example be the first access network device in the first to third aspects. When the communication device is a chip configured in an access network device, the communication interface may be an input/output interface.

Alternatively, the transceiver may be a transmit-receive circuit. Alternatively, the input/output interface may be an input/output circuit.

In a sixth aspect, a processor is provided, comprising: input circuit, output circuit and processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor performs the method in any one of the possible implementations of the first aspect to the third aspect.

In a specific implementation process, the processor may be one or more chips, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a flip-flop, various logic circuits, and the like. The input signal received by the input circuit may be received and input by, for example and without limitation, a receiver, the signal output by the output circuit may be output to and transmitted by a transmitter, for example and without limitation, and the input circuit and the output circuit may be the same circuit that functions as the input circuit and the output circuit, respectively, at different times. The embodiment of the present application does not limit the specific implementation manner of the processor and various circuits.

In a seventh aspect, a processing apparatus is provided that includes a processor and a memory. The processor is configured to read instructions stored in the memory, and may receive a signal via the receiver and transmit a signal via the transmitter to perform the method of any one of the possible implementations of the first aspect to the third aspect.

Optionally, the number of the processors is one or more, and the number of the memories is one or more.

Alternatively, the memory may be integral to the processor or provided separately from the processor.

In a specific implementation process, the memory may be a non-transient memory, such as a Read Only Memory (ROM), which may be integrated on the same chip as the processor, or may be separately disposed on different chips.

It will be appreciated that the associated data interaction process, for example, sending the indication information, may be a process of outputting the indication information from the processor, and receiving the capability information may be a process of receiving the input capability information from the processor. In particular, data output by the processor may be output to a transmitter and input data received by the processor may be from a receiver. The transmitter and receiver may be collectively referred to as a transceiver, among others.

The processing means in the seventh aspect may be one or more chips. The processor in the processing device may be implemented by hardware or may be implemented by software. When implemented in hardware, the processor may be a logic circuit, an integrated circuit, or the like; when implemented in software, the processor may be a general-purpose processor implemented by reading software code stored in a memory, which may be integrated with the processor, located external to the processor, or stand-alone.

In an eighth aspect, there is provided a computer program product comprising: a computer program (which may also be referred to as code, or instructions), which when executed, causes a computer to perform the method of any of the possible implementations of the first to third aspects described above.

In a ninth aspect, a computer-readable storage medium is provided, which stores a computer program (which may also be referred to as code or instructions) that, when executed on a computer, causes the computer to perform the method in any one of the possible implementations of the first to third aspects.

In a tenth aspect, a communication system is provided, which includes the foregoing first access network device and terminal device. Optionally, the communication system further includes the aforementioned second access network device.

Drawings

Fig. 1 is a schematic diagram of a network architecture suitable for use in the method provided by the embodiments of the present application;

fig. 2 to 10 are schematic flowcharts of a communication method provided by an embodiment of the present application;

fig. 11 and 12 are schematic block diagrams of a communication device provided in an embodiment of the present application;

fig. 13 is a schematic structural diagram of an access network device according to an embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme provided by the application can be applied to various communication systems, such as: a fifth Generation (5th Generation, 5G) mobile communication system or new radio access technology (NR). The 5G mobile communication system may include a non-independent Network (NSA) and/or an independent network (SA), among others.

The technical scheme provided by the application can also be applied to Machine Type Communication (MTC), Long Term Evolution-machine (LTE-M) communication between machines, device to device (D2D) network, machine to machine (M2M) network, internet of things (IoT) network, or other networks. The IoT network may comprise, for example, a car networking network. The communication modes in the car networking system are collectively referred to as car-to-other devices (V2X, X may represent anything), for example, the V2X may include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) or vehicle to network (V2N) communication, etc.

The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system and the like. This is not a limitation of the present application.

Fig. 1 is a schematic diagram of a network architecture suitable for the method provided by the embodiment of the present application. As shown in fig. 1, the network architecture is, for example, a 5G system (5 GS) defined in the 3rd Generation Partnership Project (3 GPP) Technical Specification (TS) 23.501. The network architecture can be divided into AN Access Network (AN) and a Core Network (CN). The access network can be used to implement radio access related functions, and the core network mainly includes the following key logical network elements: the network comprises an access and mobility management network element, a session management network element, a user plane network element, a policy control network element, a unified data management network element and the like.

The following briefly introduces the network elements shown in fig. 1:

1. user Equipment (UE): may be referred to as a terminal device, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment.

The terminal device may be a device providing voice/data connectivity to a user, e.g. a handheld device, a vehicle mounted device, etc. with wireless connection capability. Currently, some examples of terminals may be: a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiving function (e.g., a laptop, a palmtop, etc.), a Mobile Internet Device (MID), a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation security, a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol), a PDA, a wireless local loop phone (SIP), a wireless personal digital assistant (personal digital assistant, etc.) A handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle mounted device, a wearable device, a terminal device in a 5G network or a terminal device in a Public Land Mobile Network (PLMN) for future evolution, etc.

Furthermore, the terminal device may also be a terminal device in an Internet of things (IoT) system. The IoT is an important component of future information technology development, and is mainly technically characterized in that articles are connected with a network through a communication technology, so that an intelligent network with man-machine interconnection and object interconnection is realized. The IoT technology can achieve massive connection, deep coverage, and power saving of the terminal through, for example, Narrowband (NB) technology.

In addition, the terminal equipment can also comprise sensors such as an intelligent printer, a train detector, a gas station and the like, and the main functions of the terminal equipment comprise data collection (part of the terminal equipment), control information and downlink data receiving of the network equipment, electromagnetic wave sending and uplink data transmission to the network equipment.

2. Access Network (AN): the access network can provide the network access function for authorized users in a specific area, and can use transmission tunnels with different qualities according to the level of the users, the service requirements and the like. The access network may be an access network employing different access technologies. There are two types of current radio access technologies: 3GPP access technologies (e.g., radio access technologies employed in 3G, 4G, or 5G systems) and non-3GPP (non-3GPP) access technologies. The 3GPP access technology refers to an access technology conforming to 3GPP standard specifications, for example, an access network device in a 5G system is called a next generation Base station (gNB). The non-3GPP access technology refers to an access technology that does not conform to the 3GPP standard specification, for example, an air interface technology represented by an Access Point (AP) in wireless fidelity (WiFi).

An access network that implements an access network function based on a wireless communication technology may be referred to as a Radio Access Network (RAN). The radio access network can manage radio resources, provide access service for the terminal equipment, and further complete the forwarding of control signals and user data between the terminal and the core network.

The radio access networks may include, for example, but are not limited to: a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home base station (e.g., home evolved NodeB or home Node B, HNB), a baseband unit (BBU), an AP in a WiFi system, a wireless relay Node, a wireless backhaul Node, a Transmission Point (TP) or a Transmission and Reception Point (TRP), etc., and may also be a gNB or a transmission point (TRP or TP) in a 5G (e.g., NR) system, one or a group (including multiple antenna panels) of base stations in the 5G system, alternatively, it may also be a network node, such as a baseband unit (BBU), or a Distributed Unit (DU), or a base station in a next generation communication 6G system, etc. The embodiment of the present application does not limit the specific technology and the specific device form adopted by the radio access network device.

The access network may serve the cell. A terminal device may communicate with a cell via transmission resources (e.g., frequency domain resources, or alternatively, spectrum resources) allocated by an access network device.

3. Access and mobility management network elements: the method is mainly used for registration, mobility management and tracking area update processes of a terminal in a mobile network, an access and mobility management network element terminates a Non Access Stratum (NAS) message, completes registration management, connection management and reachability management, allocates a tracking area list (TA list), mobility management and the like, and transparently routes a Session Management (SM) message to a session management network element. In a 5G communication system, the access and mobility management network element may be an access and mobility management function (AMF).

4. A session management network element: the method is mainly used for session management in the mobile network, such as session establishment, modification and release. The specific functions include allocating an Internet Protocol (IP) address to the terminal, selecting a user plane network element providing a message forwarding function, and the like. In the 5G communication system, the session management network element may be a Session Management Function (SMF).

5. A user plane network element: it is mainly responsible for processing user message, such as forwarding, charging, lawful interception, etc. The user plane network element may also include a Protocol Data Unit (PDU) session anchor (PSA). In the 5G communication system, the user plane network element may be a User Plane Function (UPF).

6. Data Network (DN): can be used for providing data transmission service for terminal equipment. The data network may be a Public Data Network (PDN) network, such as the Internet (Internet), or a Local Access Data Network (LADN), such as a network of Mobile Edge Computing (MEC) nodes; but also a third party service network, an IP multimedia service (IP multi-media service) network, etc.

7. The strategy control network element: the unified policy framework is used for guiding network behaviors, providing policy rule information for control plane function network elements (such as AMF and SMF network elements) and the like.

Including a user subscription data management function, a policy control function, a charging policy control function, quality of service (QoS) control, etc. In a 5G communication system, the policy control network element may be a Policy Control Function (PCF).

It should be noted that PCF in an actual network may be further divided into multiple entities according to hierarchy or function, such as a global PCF and a PCF in a slice, or a session management PCF (SM-PCF) and an access management PCF (AM-PCF).

8. Network slice selection network element: the method is mainly used for selecting the appropriate network slice for the service of the terminal equipment. In the 5G communication system, the network slice selection network element may be a Network Slice Selection Function (NSSF).

9. Unified data management network element: for storing user data such as subscription information, authentication/authorization information, etc. In the 5G communication system, the unified data management network element may be a Unified Data Management (UDM).

In the network architecture shown in fig. 1, network elements may communicate with each other through interfaces shown in the figure. For example, the end device and the AMF may communicate through an N1 interface; the RAN and the AMF may communicate through an N2 interface, an N2 interface may be used for non-access stratum (NAS) message transmission, and the like; the RAN and the UPF may communicate via an N3 interface, an N3 interface may be used to transfer user plane data, etc.; the interfaces where the RAN connects to the core network (i.e., the N2 interface and the N3 interface) are collectively referred to as Ng interfaces; the SMF and the UPF can communicate with each other through an N4 interface, and an N4 interface can be used for transmitting tunnel identification information, data cache indication information, downlink data notification information and other information of N3 connection; the UPF and DN may communicate over an N6 interface, an N6 interface may be used to transfer user plane data, and the like. It should be understood that the communication relationship between the network elements and the interfaces is only an example, and should not limit the present application in any way. This application does not exclude the possibility of defining other interfaces in future protocols for communication between the above-mentioned network elements or between other network elements.

It should be understood that the network architecture applied to the embodiments of the present application is only an exemplary network architecture described in terms of a conventional point-to-point architecture and a service architecture, and the network architecture to which the embodiments of the present application are applied is not limited thereto, and any network architecture capable of implementing the functions of the network elements described above is applicable to the embodiments of the present application.

It should also be understood that the AMFs, SMFs, UPFs, network slice selection function network elements (NSSFs), PCFs, UDMs shown in fig. 1 may be understood as network elements in the core network for implementing different functions, e.g., may be combined into a network slice as needed. The core network elements may be independent devices, or may be integrated in the same device to implement different functions, and the specific form of the network elements is not limited in the present application.

It is also to be understood that the above-described nomenclature is defined merely to distinguish between different functions, and is not intended to limit the application in any way. This application does not exclude the possibility of using other nomenclature in 5G networks and other networks in the future. For example, in a 6G network, some or all of the above network elements may follow the terminology in 5G, and may also adopt other names, etc. The name of the interface between each network element in fig. 1 is only an example, and the name of the interface in the specific implementation may be other names, which is not specifically limited in this application. In addition, the name of the transmitted message (or signaling) between the network elements is only an example, and the function of the message itself is not limited in any way.

To facilitate understanding of the embodiments of the present application, first, a brief description will be given of terms referred to in the present application.

1. Session (session): and data transmission between the terminal equipment and the DN can be realized. In this embodiment of the present application, the session may be, for example, a Protocol Data Unit (PDU) session. The 5G core network (5G core, 5GC) supports PDU connection services. The PDU connect service may refer to a service in which PDU packets are exchanged between a terminal device and a DN. The PDU connection service is implemented by the terminal device initiating the establishment of a PDU session. After a PDU session is established, a data transmission channel between the terminal device and the DN is established. Each end-point device may establish one or more PDU sessions. A PDU session may be identified by a PDU session identifier (PDU session ID). In other words, one possible form of identification information of a session is a PDU session identification.

It should be understood that the PDU session is one possible form of session, and should not be construed as limiting the application in any way.

2. Network Slicing (NS): a network slice is an end-to-end logical private network that provides specific network capabilities. Through flexible allocation of network resources and networking on demand, a plurality of mutually isolated logic subnets with different characteristics can be simulated on the same set of physical facilities to provide services for users in a targeted manner. This logical subnet is called a network slice. The network slice can be used by an operator, and provides mutually isolated and function-customizable network services for different vertical industries, different clients and different services based on a Service Level Agreement (SLA) signed by a client. Different network slices can be identified and distinguished by single network slice selection assistance information (S-NSSAI).

There are often many access network devices, such as the gNB, within the entire service area of a network slice. Each access network device has a coverage area, which may be one or more cells (cells), and each Cell has a unique global identity (CGI). The service area of the entire network slice is divided into several areas, i.e., one or more Tracking Areas (TAs). The TA may be identified using a Tracking Area Identifier (TAI). The TA consists of one or more cells.

3. Cell (cell): the cells are described by higher layers from the point of view of resource management, mobility management or serving elements. The coverage area of each access network device may be divided into one or more cells, and each cell may correspond to a frequency range. Each cell may operate in a corresponding frequency range. The frequency range may be a frequency point or a frequency band. This is not a limitation of the present application.

It should be noted that a cell may be an area within the coverage of a wireless network of access network devices. In the embodiment of the present application, different cells may correspond to the same or different access network devices.

For example, the access network device serving cell #1 and the access network device serving cell #2 may be different access network devices, such as base stations. That is, cell #1 and cell #2 may be managed by different base stations.

As another example, the access network device serving cell #1 and the access network device serving cell #2 may be the same access network device, e.g., a base station. That is, cell #1 and cell #2 may be managed by the same base station, and in this case, cell #1 and cell #2 may be said to be co-sited.

One possible scenario in which cell #1 and cell #2 are co-sited is that the access network device serving cell #1 and the access network device serving cell #2 are different radio frequency processing units of the same base station, such as Radio Remote Units (RRUs), that is, cell #1 and cell #2 may be managed by the same base station, have the same baseband processing unit and intermediate frequency processing unit, but have different radio frequency processing units.

The source cell is a cell where the terminal device resides before handover, or a cell where the terminal device resides before cell reselection. The source cell in the embodiment of the present application is a cell served by the first access network device. The target cell is a cell that the first access network device determines for the terminal device that it wishes to handover to. The target cell in the embodiment of the present application may be a cell served by the first access network device, and may also be a cell served by the second access network device.

The cells served by each access network device may be one or more. Cells served by the same access network equipment may operate in different frequency ranges or may operate in the same frequency range.

It should be understood that the radio resources supported by each cell are not limited to the frequency range, and may also include time domain resources, space domain resources, and the like, which are not illustrated in this embodiment.

4. Handover (handover): in a wireless communication system, when a terminal device moves/approaches from one cell to another cell, handover is required in order to keep the communication of the terminal device uninterrupted. In this embodiment, the source cell represents a cell that provides service for the terminal device before handover, and the target cell represents a cell that provides service for the terminal device after handover.

The handover may be intra-site handover or inter-site handover. The intra-station handover may refer to that the source cell and the target cell belong to the same access network device (e.g., a gNB); and inter-station handover means that the source cell and the target cell belong to different access network equipment (such as gNB). This is not limited in this application.

5. RRC connection: the terminal device may establish an RRC connection with the network device, or in other words, with the cell, prior to normal communication. When the RRC connection is disconnected, the terminal device may enter an RRC idle state (which may also be referred to as an idle state for short) and cannot normally communicate.

When the terminal device is in the RRC connected state, the terminal device may transmit data through the currently activated session, and may also request to establish a session or request to activate a session. When the terminal device is in the RRC idle state, the terminal device cannot establish or activate a session, and the session activated in the RRC connected state is also deactivated.

6. Intra-station neighbor cell: adjacent cells served by the same access network equipment. For example, cell #1 and cell #2 hereinafter are intra-station neighbor cells.

7. Out-of-station neighbor cell: adjacent cells served by different access network equipment. For example, cell #1 and cell #4 hereinafter are out-of-station neighbor cells.

For better understanding of the embodiments of the present application, the following description is first made:

first, for ease of understanding and explanation, the following assumptions and definitions are made:

cell # 1: the cell where the terminal device resides before handover, or the cell where the terminal device resides before cell reselection. I.e. the above-mentioned source cell.

It should be understood that both the source cell and the target cell are relative to a terminal device. For example, the cell #1 is a source cell of the terminal device in the embodiment of the present application, but may also be a target cell of another terminal device.

Cell # 2: a cell co-sited with cell #1, and cell #2 is a neighbor cell of cell # 1. Since cell #1 and cell #2 are co-sited, cell #2 may be said to be an intra-site neighbor cell of cell # 1. It should be understood that the intra-station neighboring cells of cell #1 may include, but are not limited to, cell #2, e.g., also cell # 3.

Cell # 3: another intra-station neighbor cell of cell # 1.

Cell # 4: a cell not co-sited with cell #1, and cell #4 is a neighboring cell of cell # 1. Since cell #1 and cell #4 are not co-sited, cell #4 may be said to be an out-of-station neighbor cell of cell # 1. It should be understood that the off-site neighbor cells of cell #1 may include, but are not limited to, cell # 4.

The first access network device: access network equipment serving cell # 1. The cell served by the first access network device may include only cell #1, may also include cell #2, and may also include other cells besides cell #1 and cell #2, such as cell # 3.

The second access network device: an access network device different from the first access network device. The cell served by the second access network device may include only cell #4, or may include other cells than cell # 4.

It should be understood that the cell served by the second access network device is adjacent to the cell served by the first access network device, e.g., one or more of the cells served by the second access network are adjacent cells to cell # 1. The second access network device may thus be said to be an access network device having a neighbouring cell relationship with the first access network device. However, it should be understood that the access network device having the adjacent cell relationship with the first access network device is not necessarily limited to the second access network device, and the second access network device is taken as an example for convenience of understanding and description. This should not be construed as limiting the application in any way.

S-NSSAI # 1: identification of the corresponding network slice for session 1.

S-NSSAI # 2: identification of the corresponding network slice for session 2.

S-NSSAI # 3: identification of the corresponding network slice for session 3.

Target frequency range: the frequency range supported by the target cell. The first access network device preferentially selects a first frequency range supported by the source cell (e.g., cell #1) as the target frequency range.

The first frequency range: the frequency range supported by the source cell, that is, the frequency range corresponding to the first radio resource of the source cell. For example, in the embodiment of the present application, the first frequency range is the N41 frequency band.

It should be understood that for ease of differentiation and illustration, different access network devices, different cells, different network slices, and different sessions are differentiated by the different numbering described above in this application. These numbers are merely examples and should not be construed as limiting the present application in any way. The present application also does not limit the specific form of the identity of the gNB, cell, network slice, and session.

Second, in the present application, the related description referring to the network element a sending a message or data to the network element B, and the network element B receiving the message or data from the network element a, is intended to explain to which network element the message or data is intended, and does not limit whether the message or data is sent directly or indirectly via other network elements.

For example, the first access network device described herein sends a message or a data packet to the second access network device, and it is not limited that the first access network device directly sends a message or a data packet to the second access network device. In the Ng handover scenario, since the first access network device and the second access network device do not support the communication of the Xn interface, the communication between the first access network device and the second access network device may be forwarded through the AMF. In the Xn handover scenario, since the first access network device and the second access network device support the Xn interface communication, the first access network device and the second access network device can directly interact without the forwarding of the AMF. Although not listed one by one, the meaning will be understood by those skilled in the art.

Third, in a plurality of flowcharts shown below, each embodiment is described by taking an Xn interface as an example. If there is no Xn interface between the first access network device and the second access network device, Ng interface switching is performed.

In addition, in the absence of the Xn interface, the OAM may send configuration information for each access network device to indicate the network slices respectively supported by the cells served by each access network device and the frequency ranges corresponding to each network slice, and the first access network device and the second access network device may no longer exchange the network slices respectively supported by each other and the frequency ranges corresponding to each network slice with each other through the Xn interface.

In addition, the interaction between the first access network device and the second access network device may be forwarded through the AMF without the Xn interface. Other procedures are substantially similar, and for the sake of brevity, no additional description of the embodiments is provided below.

Fourth, in the embodiments of the present application, the descriptions "when … …", "in … …", "if" and "if" all refer to that a device (e.g., a terminal device or a network device) performs corresponding processing under a certain objective condition, and do not limit the time, and do not require a certain judgment action when the device (e.g., a terminal device or a network device) is implemented, and do not mean that there are other limitations.

Fifth, the first, second and various numerical numbers in the embodiments shown below are merely for convenience of description and are not intended to limit the scope of the embodiments of the present application. E.g., to distinguish between different multicast data, different UEs, different PDU sessions, etc.

Sixth, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, at least one (one) of a, b, and c, may represent: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b and c. Wherein a, b and c may be single or plural respectively.

Seventh, a plurality of existing signaling is listed in the following embodiments. It should be understood that the names of these signaling are merely examples for ease of understanding and should not be construed as limiting the present application in any way. This application does not exclude the possibility of defining other signalling names in future protocols instead of the signalling names listed in this application to achieve the same or similar functionality. For example, the "RRC connection release message" may be an "RRC release message" or the like. For the sake of brevity, this is not to be enumerated here.

The communication method provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings.

Fig. 2 is a schematic flow chart of a communication method 200 according to an embodiment of the present application. As shown in fig. 2, the method 200 may include steps 210 through 230. The steps of method 200 are described in detail below.

In step 210, the first access network device determines that the terminal device satisfies a cell handover condition.

In step 220, the first access network device determines a target cell.

In step 230, the first access network device controls the terminal device to switch to the target cell.

The first access network device can actively search a target cell for the terminal device and control the terminal device to switch to the target cell under the condition that the terminal device meets the cell switching condition. The cell reselection is initiated without depending on the terminal equipment entering an idle state, so that the cell is not switched until the current service of the terminal equipment is finished. Therefore, the terminal equipment can be switched to a proper cell in time, so that the communication quality of the terminal equipment can be improved in a short time, and the improvement of user experience is facilitated.

Optionally, the determining, by the first access network device, that the terminal device meets the cell switching condition in step 210 specifically includes: the first access network equipment determines that the signal quality of the terminal equipment in the source cell is lower than a preset threshold.

The signal quality can be evaluated by, for example, Reference Signal Receiving Power (RSRP), Reference Signal Receiving Quality (RSRQ), or the like. Illustratively, the estimation may be based on RSRP or RSRQ of a Reference Signal (RS) of a certain cell received by the terminal device. It is to be understood that RSRP, RSRQ, etc. may be understood as indicators for evaluating signal quality.

The preset threshold may be understood as a threshold value used to determine whether the signal quality is good or bad. The indicators used for evaluation are different, and the corresponding threshold values are also different. Further, the preset threshold may be a predefined threshold value. The present application is not limited to specific values. In order to facilitate distinguishing from the threshold value in the following, the threshold for judging the signal quality of the terminal device in the source cell is recorded as a first preset threshold.

One possible scenario is that the terminal device and the first access network device may be in an RRC connected state. The terminal device may have established and activated one or more sessions in the source cell. The terminal device may conduct data transmission through the activated one or more sessions.

If the first access network device determines that the signal quality of the terminal device in the source cell is lower than the first preset threshold, the terminal device can be determined to meet the cell switching condition. The first access network device may perform step 220 of determining a target cell and step 230 of controlling the terminal device to handover to the target cell.

The embodiment described below in conjunction with fig. 3 shows a specific flow of the communication method in this scenario.

Optionally, the determining, by the first access network device, that the terminal device meets the cell switching condition in step 210 specifically includes: the first access network device determines that the first wireless resource of the source cell does not support a first network slice corresponding to a first session requested to be established or activated by the terminal device in the source cell.

The radio resources may include, but are not limited to, frequency domain resources, time domain resources, spatial domain resources, code domain resources, and the like. The frequency domain resources may specifically refer to frequency ranges supported by a cell. Alternatively, the cell is capable of operating in the supported frequency domain.

In the embodiment of the present application, for convenience of differentiation and description, a radio resource supported by a source cell is denoted as a first radio resource, a session that a terminal device requests to establish or request to activate in the source cell is denoted as a first session, and a network slice corresponding to the first session is denoted as a first network slice. The first radio resource does not support the first network slice corresponding to the first session requested to be established or requested to be activated by the terminal device, which may specifically mean that the frequency range corresponding to the first radio resource does not support the first network slice, or that the source cell does not support the first network slice. Therefore, the frequency range provided by the source cell cannot provide the access service for the first network slice corresponding to the first session requested to be established or activated by the terminal device. Since each cell may operate in the corresponding frequency range in a normal case, or each cell may provide an access service of the supported network slice in its corresponding frequency range, the frequency range corresponding to the first radio resource of the source cell does not support the first network slice, that is, the source cell does not support the first network slice.

One possible scenario is that the terminal device accesses the network after being powered on, or initiates a registration request to the network because it moves to a new TA that does not belong to the original registration area. Or when the terminal equipment periodically updates the registration to the network, the terminal equipment initiates a registration request to the network. The terminal device may carry a session list requesting establishment or activation in the registration request. The session list includes identification information of sessions requested to be established and/or activated by the terminal device. The session that the terminal device requests to establish or requests to activate may include, for example but is not limited to, the first session. The embodiment described below in conjunction with fig. 4 shows a specific flow of the communication method in this scenario.

Another possible scenario is that when the terminal device changes from the RRC idle state to the RRC connected state, it is desirable to activate the user plane connection with the session deactivated in the RRC idle state. The terminal device may carry the session list requested to be activated when initiating the RRC connection request to the first access network device. The session list may include identification information of the session requested to be activated by the terminal device. The session requested to be activated may include, for example, but is not limited to, the first session. The embodiment described below in conjunction with fig. 5 shows a specific flow of the communication method in this scenario.

Yet another possible scenario is that the terminal device desires to establish a new session. The terminal device may send a session establishment request message to the first access network device to request establishment of one or more sessions. The one or more sessions that the terminal device requests to be established may include, for example, but are not limited to, the first session. The embodiments described below in conjunction with fig. 6 and 7 show a specific flow of the communication method in this scenario.

In any of the foregoing multiple possible scenarios, if the first access network device determines that the first radio resource does not support the first network slice corresponding to the first session requested to be established or requested to be activated by the terminal device, it may be determined that the terminal device satisfies the cell handover condition. The first access network device may perform step 220 of determining a target cell and step 230 of controlling the terminal device to handover to the target cell.

The target cell determined by the first access network device for the terminal device may be an intra-station adjacent cell of the source cell or an extra-station adjacent cell of the source cell, which is not limited in this application.

In one possible implementation, the first access network device may preferentially find the target cell among the intra-station neighboring cells. If the target cell can be found in the intra-site adjacent cells, the terminal device can perform intra-site cell handover without switching the access network device. If the first access network device cannot find a suitable cell in the intra-station adjacent cells as the target cell, the first access network device may find the target cell in the extra-station adjacent cells. If the first access network device finds the target cell in the adjacent cells outside the station, the terminal device may execute cross-station cell switching, and the terminal device needs to switch the access network device at this time. It is assumed here that the terminal device is handed over to a second access network device, which is the access network device serving the target cell.

In another possible implementation, the first access network device determines that the cells it serves include only cell #1, and the first access network device finds the target cell directly from an off-site neighbor cell. If the first access network device finds the target cell in the adjacent cells outside the station, the terminal device can execute cross-station cell switching, and the terminal device needs to be switched to the second access network device at the moment.

Since the following will describe the specific process of applying the communication method provided by the present application to the above scenario in conjunction with fig. 3 to 7, the detailed description is omitted here for brevity.

Fig. 3 is another schematic flow chart of a communication method provided in an embodiment of the present application. The method 300 shown in fig. 3 may include steps 301 through 307.

To facilitate understanding of the present embodiment, the following description is first made of a scenario in which the method 300 is applied: the terminal equipment and the first access network equipment are in an RRC connection state. The terminal device is in a cell #1 served by the first access network device, and the terminal device has an active session 1 in the cell #1, and the network slice corresponding to the session 1 is a network slice identified as S-NSSAI # 1. The cells served by the first access network device may also include cell #2, cell #2 being a neighbor cell of cell # 1. It should be understood that session 1 is an example of the first session and the network slice identified as S-NSSAI #1 is an example of the first network slice.

In method 300, step 303 may correspond to step 210 in method 200, illustrating one possible implementation of the first access network device determining that the terminal device satisfies the cell handover condition in step 210.

Step 304 may correspond to step 220 of method 200, illustrating a possible implementation of the first access network device determining the target cell in step 220. In step 304, it may be the case that the target cell is a cell other than the source cell of the plurality of cells served by the first access network device. That is, the first access network device may determine the target cell from within-station neighboring cells. Another possible scenario is where the target cell is a cell served by the second access network device. That is, the first access network device may determine the target cell from the off-site neighbor cells. In the case where the target cell is determined from the out-of-station neighbor cells, the method may further include: the method comprises the steps that a first access network device determines wireless measurement parameters according to a first network slice, network slices respectively supported by at least one adjacent cell and wireless resources corresponding to the supported network slices; the first access network equipment sends wireless measurement parameters to the terminal equipment, the wireless measurement parameters are used for measuring the signal quality of the adjacent cells by the terminal equipment, and the measurement of the signal quality of the adjacent cells by the terminal equipment is used for determining the target cell.

Step 305 may correspond to step 230 of method 200, showing a possible implementation of the first access network device controlling the handover of the terminal device to the target cell in step 230. Corresponding to step 304, one possible implementation manner of step 305 is that the first access network device controls the terminal device to perform intra-station handover. Another possible implementation manner of step 305 is that the first access network device controls the terminal device to perform cross-site handover. In the case of cross-site handover, the method may further include: 3051, a first access network device sends a request message to a second access network device, wherein the request message carries identification information of a first session and identification information of a first network slice; step 3052, the second access network equipment determines RRC parameters according to the information of the session to be switched in; step 3053, the first access network device receiving an RRC parameter for handover from the second access network device; 3054, the first access network device sends the RRC parameter to the terminal device; and step 3055, the terminal device accesses the radio resource of the second access network device according to the RRC parameter. Optionally, the RRC parameter is associated with radio resources corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device.

The method 300 is described in detail below with reference to specific flow diagrams.

In step 301, the first access network device receives, from the OAM, first configuration information, where the first configuration information is used to indicate network slices supported by the first access network device and radio resources corresponding to each network slice.

For example, in the network slice planning and deployment process, an administration and maintenance (OAM) entity (hereinafter, OAM) may send configuration information to each access network device. Configuration information sent by the OAM to each access network device may be respectively used to indicate a network slice supported by each access network device and a radio resource corresponding to the supported network slice. Configuration information sent by the OAM to the first access network device may be denoted as first configuration information. Since the radio resources include frequency domain resources, the radio resources corresponding to the network slice include a frequency range corresponding to the network slice.

It should be understood that the first access network device may configure the respectively supported network slice and frequency range for each cell based on the first configuration information. Thereby, the network slices supported by each cell and the frequency ranges corresponding to each network slice can be determined. It should also be understood that when there are multiple cells served by the first access network device, the network slices supported by each cell and the frequency ranges corresponding to each network slice are not necessarily the same. As previously described, each cell may correspond to a frequency range. Or, each cell operates in the frequency range it supports.

An example, the first configuration information may include: { S-NSSAI #1, (N41) } and { S-NSSAI #2, (N41) }, indicating that the first access network equipment supports an access service providing network slices identified as S-NSSAI #1 and S-NSSAI #2 in the N41 band.

Assume that the cells served by the first access network device include cell #1 and cell # 2. The first access network device may configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell #1 may include, for example, a network slice identified as S-NSSAI #1, which corresponds to a frequency range of N41 frequency bands. The network slices supported by cell #2 may include, for example, network slices identified as S-NSSAI #1 and S-NSSAI #2, which correspond to a frequency range of the N41 frequency band.

For another example, the first configuration information may include: { S-NSSAI #1, (N41) } and { S-NSSAI #2, (N41, N79) }, which indicate that the first access network device supports an access service providing the network slices identified as S-NSSAI #1 and S-NSSAI #2 in the N41 band, and supports an access service providing the network slices identified as S-NSSAI #2 in the N79 band.

Assume that the cells served by the first access network device include cell #1 and cell # 2. The first access network device may configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell #1 may include, for example, network slices identified as S-NSSAI #1 and S-NSSAI #2, which correspond to a frequency range of the N41 frequency band. The network slices supported by cell #2 may include, for example, a network slice identified as S-NSSAI #2, which corresponds to a frequency range of N79 frequency bands.

As yet another example, the first configuration information may include: { S-NSSAI #1, (N41, N79) } and { S-NSSAI #2, (N41) }, which indicate that the first access network device supports an access service providing the network slices identified as S-NSSAI #1 and S-NSSAI #2 in the N41 band, and supports an access service providing the network slice identified as S-NSSAI #1 in the N79 band.

Assume that the cells served by the first access network device include cell #1, cell #2, and cell # 3. The first access network device may configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell #1 may include, for example, a network slice identified as S-NSSAI #1, which corresponds to a frequency range of N41 frequency bands. The network slices supported by cell #2 may include, for example, network slices identified as S-NSSAI #1 and S-NSSAI #2, which correspond to a frequency range of the N41 frequency band. The network slices supported by cell #3 may include, for example, the network slice identified as S-NSSAI #1, and the frequency range supported by cell #3 is the N79 frequency band.

It should be understood that the network slice does not have to be the same for the frequency ranges corresponding to different cells, depending on the frequency range supported by each cell.

It should also be understood that the above listed network slices supported by each cell and the corresponding frequency ranges of each network slice and the frequency ranges supported by each cell are only examples, and should not limit the present application in any way. The network slices supported by each cell, the frequency ranges corresponding to the network slices, and the frequency ranges supported by the cells are not limited in the present application.

It should be noted that, when an operator performs network planning, in order to ensure that the handover of the terminal device is the same-frequency handover as much as possible, multiple cells operating in the same frequency range may all support the same network slice. For example, cell #1 and cell #2 both support operation in the N41 band, and cell #1 and cell #2 both support network slices identified as S-NSSAI # 1.

For convenience of understanding and explanation hereinafter, it is assumed that the first configuration information may include: { S-NSSAI #1, (N41, N79) } and { S-NSSAI #2, (N41) }. The cells served by the first access network device include cell #1, cell #2, and cell # 3. The first access network device may configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell #1 may include, for example, a network slice identified as S-NSSAI #1, which corresponds to a frequency range of N41 frequency bands. The network slices supported by cell #2 may include, for example, network slices identified as S-NSSAI #1 and S-NSSAI #2, which correspond to a frequency range of the N41 frequency band. The network slices supported by cell #3 may include, for example, the network slice identified as S-NSSAI #1, and the frequency range supported by cell #3 is the N79 frequency band.

In step 302, the first access network device obtains second configuration information of the second access network device, where the second configuration information is used to indicate the network slices supported by the second access network device and the radio resources corresponding to each network slice.

In one implementation, the first access network device may receive second configuration information from the second access network device. For example, the first access network device may obtain the second configuration information through an Xn interface. For example, if the first access network device and the second access network device may communicate via an Xn interface, the first access network device may obtain the second configuration information via the Xn interface. Alternatively, the second access network device may also receive the second configuration information from the OAM by the method described in step 301 above.

For example, the second configuration information sent by the OAM to the second access network device may include: { S-NSSAI #1, (N41, N79) }, { S-NSSAI #2, (N79) }, and { S-NSSAI #3, (N79) }, indicating that the second access network device supports an access service providing a network slice identified as S-NSSAI #1 in an N41 band, and supports an access service providing a network slice identified as S-NSSAI #1, S-NSSAI #2, and S-NSSAI #3 in an N79 band.

Step 302 in fig. 3 illustrates an implementation in which the second access network device receives the second configuration information from the OAM, and the first access network device receives the second configuration information from the second access network device.

It should be understood that the second configuration information received by the first access network device from the second access network device may be the same as or different from the second configuration information received by the second access network device from the OAM, and for example, may be sent to the first access network device after being processed by the second access network device.

In another implementation, the first access network device may receive the second configuration information from the OAM. For example, the OAM may send the first configuration information and the second configuration information to the first access network device through the same signaling. Of course, the OAM may also send the configuration information of other access network devices to the first access network device through the same signaling, where the other access network devices may refer to access network devices having an adjacent cell relationship with the first access network device.

It should be noted that step 302 is an optional step. When the target cell determined by the first access network device in the subsequent step is the intra-station neighboring cell, the first access network device does not actually use the information acquired in step 302.

In step 303, the first access network device determines that the signal quality of the terminal device in cell #1 is lower than a first preset threshold.

The terminal device has established a first session in cell #1 and the user plane connection for this first session has been activated. The first network slice corresponding to the first session is identified as S-NSSAI # 1. The context (context) of the terminal device saved by the first access network device includes information of the first session.

It should be understood that the session that the terminal device has established and activated in the cell #1 is not necessarily limited to the first session, and may have established and activated a plurality of sessions. For ease of understanding and explanation, the method flow provided by the present application is described herein with reference to the first session as an example.

The first access network device may determine whether the signal quality of the terminal device in the cell #1 is lower than a first preset threshold according to the measurement of the signal quality of the cell #1 by the terminal device. If the signal quality of the terminal device in the cell #1 is lower than the first preset threshold, that is, the signal quality of the terminal device in the cell #1 is not good. The first access network device may thus determine that the terminal device is not suitable for continuing to camp in cell #1, the terminal device satisfying the cell handover condition.

In an implementation manner, the terminal device may measure the signal quality of the source cell, and report a measurement result (e.g., the RSRP, RSRQ, or other parameters) to the first access network device. The first access network device may determine whether the signal quality satisfies a first predetermined threshold according to the measurement result. The first access network device may further determine that the terminal device satisfies the cell handover condition when the signal quality is lower than a first preset threshold.

In another implementation, the terminal device may report, according to the measurement of the signal quality of the source cell, an event that the signal quality is lower than the first preset threshold to the first access network device when the signal quality is lower than the first preset threshold. The first access network equipment determines that the terminal equipment meets the cell switching condition according to the first access network equipment.

It should be understood that the measurement of the signal quality of the cell #1 by the terminal equipment can refer to the prior art, and for the sake of brevity, will not be described in detail here.

In step 304, the first access network device determines a target cell according to a first network slice corresponding to the first session and network slices respectively supported by at least one neighboring cell.

To maintain normal communication for the first session, the first access network device may be considered in connection with the first network slice corresponding to the first session when determining the target cell for the terminal device. That is, the first access network device supports the first network slice for the target cell determined by the terminal device to avoid interruption of the first session.

The first access network device may select a cell supporting the first network slice from the at least one neighboring cell as a target cell according to the first network slice and the network slices respectively supported by the at least one neighboring cell acquired in advance.

The first access network device may preferentially find the target cell among the intra-station neighbor cells. If the first access network equipment finds the target cell in the adjacent cells in the station, the target cell is other cells except the source cell in a plurality of cells served by the first access network equipment.

For example, if the intra-station neighboring cell of the cell #1 includes the cell #2, and the cell #2 also supports the first network slice, the first access network device may determine whether the cell #2 may be the target cell according to the signal quality of the cell # 2. If the signal quality of the cell #2 satisfies a predetermined threshold (for convenience of differentiation and explanation, the predetermined threshold is denoted as a second predetermined threshold), it may be regarded as the target cell.

As an example, the first network slice is identified as S-NSSAI #1, and the network slices supported by cell #2 include network slices identified as S-NSSAI #1 and S-NSSAI #2, then cell #2 also supports the first network slice. The first access network device may further determine whether the target cell is available based on the signal quality of cell # 2.

For another example, the first access network device may search for a neighboring cell of the cell #1 from the cells whose signal quality satisfies the second preset threshold according to the signal quality of each cell in the station. If a neighboring cell of the cell #1 can be found from the cells whose signal quality satisfies the second preset threshold, the cell can be determined as the target cell.

An example, the first network slice is identified as S-NSSAI # 1. The first access network device determines that there are cells satisfying a second preset threshold in the station, including cell # 2. As previously described, cell #2 also supports network slices identified as S-NSSAI #1, and thus cell #2 may be the target cell.

For another example, the intra-station neighboring cells of the cell #1 include a plurality of cells supporting the first network slice, and the frequency ranges supported by the plurality of cells supporting the first network slice are different, so that the first access network device may preferentially search for the target cell in the cell range with the same frequency as the cell # 1.

Here, the same frequency may specifically mean that the frequency ranges supported by the two cells are the same, for example, the two cells operate in the same frequency range; in contrast, inter-frequency may specifically refer to frequency ranges supported by two cells that are different, for example, operating in different frequency ranges.

As an example, the first network slice is identified as S-NSSAI #1, and the frequency range supported by cell #1 is the N41 frequency band. The intra-station neighboring cells of the cell #1 include a cell #2 and a cell # 3. Assuming that the network slices supported by cell #2 include network slices identified as S-NSSAI #1 and S-NSSAI #2, the frequency range supported by cell #2 is the N41 frequency band; the network slice supported by cell #3 includes the network slice identified as S-NSSAI #1, and the frequency range supported by cell #3 is the N79 frequency band. The first access network device may prioritize whether the signal quality of cell #2 reaches a second preset threshold. If the signal quality of the cell #2 satisfies the second predetermined threshold, the cell #2 may be used as the target cell.

It should be noted that the first access network device may obtain the measurement result of the signal quality of each cell from other terminal devices in the multiple cells served by the first access network device at the same time, and therefore, the first access network device may determine whether the intra-station adjacent cell supporting the first network slice satisfies the second preset threshold according to the measurement result of the signal quality of the intra-station adjacent cell.

It should be understood that the second predetermined threshold may be understood as another threshold value used to determine whether the signal quality is good or poor. The indicators used for evaluation are different, and the corresponding threshold values are also different. Further, the second preset threshold may be a predefined threshold value. The present application is not limited to specific values.

It is also understood that the first and second predetermined thresholds are different predetermined thresholds. The two can adopt different indexes; or, the same index and different threshold values can be adopted; alternatively, the same index and the same threshold value may be used. This is not a limitation of the present application.

The first access network device may also find the target cell from an off-site neighbor cell. If the first access network device finds a target cell from the off-site neighboring cells, the target cell may be, for example, a cell served by the second access network device.

The first access network device seeks a target cell from the off-site neighbor cells, also based on the cells supporting the first network slice. The specific implementation process is similar to the above-described process of searching for the target cell in the intra-station neighboring cells, and for brevity, the detailed description is omitted here.

In this embodiment, in a possible implementation manner of step 304, the first access network device may determine a target frequency range according to the first network slice, the network slices respectively supported by the at least one out-of-station neighboring cell, and the radio resources corresponding to each network slice, and then find the target cell based on the target frequency range.

Illustratively, this step 304 may specifically include:

step 3041, the first access network device determines a target frequency range according to the first network slice, the network slices supported by at least one neighboring cell, and the frequency ranges corresponding to the network slices;

step 3042, the first access network device determines a target cell according to the target frequency range.

In step 3041, the target frequency range is a frequency range that can be supported by the target cell determined by the first access network device for the terminal device.

The first access network device may search for a cell supporting the first network slice from at least one neighboring cell according to the first network slice, and determine a target frequency range according to a frequency range corresponding to each cell of the first network slice.

Since the frequency ranges supported by the cells are different, although there may be a plurality of cells supporting the first network slice, the frequency ranges corresponding to the cells are not necessarily the same. Therefore, the target frequency range may be the same frequency range as the cell #1 or a different frequency range from the cell #1, and the present application does not limit this. For convenience of differentiation and explanation, the frequency range supported by cell #1 is denoted as the first frequency range.

In one implementation, the first access network device may preferentially select the same frequency range as cell #1 as the target frequency range. Preferentially selecting the first frequency range as a target frequency range under the condition that the adjacent cells support the first network slice and the corresponding frequency range is the cell of the first frequency range; otherwise, selecting other frequency ranges corresponding to the first network slice supported by the adjacent cell as the target frequency range. For the sake of distinction and illustration, a frequency range different from the first frequency range corresponding to the first network slice supported by the neighboring cell is referred to as a second frequency range. In other words, the target frequency range is first the first frequency range and second the second frequency range.

As shown in the above example, the first frequency range is the N41 frequency band. Among the neighboring cells of the cell #1, a cell supporting the network slice identified as S-NSSAI #1 has a frequency range corresponding to the network slice, which includes N41 and N79 frequency bands. The target frequency range preferentially selects the N41 band. It is to be understood that if the neighboring cell of cell #1 does not support the N41 band, the target frequency range may be the N79 band. The N79 band is an example of the second frequency range.

Optionally, step 3042 specifically includes: the first access network device determines a target cell from the intra-site neighboring cells supporting the target frequency range.

For example, if the first access network device determines that the target frequency range is the first frequency range, the first access network device may first determine whether a cell supporting the first frequency range exists in intra-station neighboring cells of the cell #1, for example, denoted as the first cell. In the presence of the first cell, the first access network device may determine whether to determine the first cell as the target cell based on a signal quality of the first cell. For example, if the signal quality of the first cell meets the second preset threshold, the first cell is determined as the target cell. If the signal quality of the first cell is lower than the second preset threshold, or the cell #1 does not exist in the intra-station neighboring cells (i.e., the cell served by the first access network device only includes the cell #1), the first access network device may determine the target cell in the extra-station neighboring cells.

Optionally, step 3042 specifically includes: the first access network device determines a target cell from the off-site neighboring cells that support the target frequency range. If the first access network device determines that the target frequency range is the first frequency range, the wireless measurement parameter may be determined based on the first frequency range. For the sake of distinction and illustration, the wireless measurement parameter determined based on the first frequency range is denoted as the first wireless measurement parameter.

The first access network device may send the first radio measurement parameter to the terminal device. The terminal device may make a measurement of the signal quality of the neighboring cell based on the first radio measurement parameter. In other words, the first radio measurement parameter triggers the terminal device to perform the intra-frequency measurement.

As described above, when an operator performs network planning, in order to ensure that the handover of a terminal device is a same-frequency handover as much as possible, multiple cells operating in the same frequency range may all support the same network slice. It can thus be appreciated that the measurement of the signal quality of the neighbouring cell by the terminal device based on the first radio measurement parameter is a measurement in the first frequency range, i.e. a measurement of the signal quality of the neighbouring cell supporting the first frequency range and supporting the first network slice.

And then, the terminal equipment reports the measurement result to the first access network equipment. It can be understood that the measurement result reported by the terminal device is a measurement result obtained by measuring the signal quality of the neighboring cell in the first frequency range based on the first radio measurement parameter. Illustratively, the measurement result may include cell identities of one or more neighboring cells and signal qualities corresponding to the neighboring cells.

It will be appreciated that the cells reported in the measurement results are substantially all capable of providing access services for the first network slice in the first frequency range. The first access network device may determine a target cell based on the measurement. As described above, the first access network device may determine a cell whose signal quality satisfies a preset threshold as the target cell. If the first access network device can find the target cell based on the measurement result reported by the terminal device, the first access network device does not need to determine the wireless measurement parameters based on other frequency ranges, and the terminal device does not need to perform inter-frequency measurement.

If the first access network device does not find the target cell based on the measurement result reported by the terminal device, for example, the signal quality of each neighboring cell is lower than the second preset threshold, the first access network device may use the second frequency range as the target frequency range, and try to find the target cell in the intra-station neighboring cell and the extra-station neighboring cell based on the second frequency range. It can be appreciated that if the first access network device can find the target cell among the intra-site neighboring cells based on the second frequency range, it is not necessary to go to the extra-site neighboring cells to find the target cell.

The specific process of the first access network device searching for the target cell in the intra-station adjacent cell based on the second frequency range is the same as the specific process of the first access network device searching for the target cell in the intra-station adjacent cell based on the first frequency range, which is not repeated here for brevity.

The specific process of the first access network device searching the target cell in the out-of-station adjacent cell based on the second frequency range may be implemented by performing the steps of determining the wireless measurement parameter, issuing the wireless measurement parameter, and determining the target cell according to the measurement result.

In contrast, when determining the radio measurement parameter, the first access network device may determine the radio measurement parameter based on the second frequency range, with the second frequency range as the target frequency range. For the sake of distinction and illustration, the wireless measurement parameter determined based on the second frequency range is referred to as the second measurement parameter.

The first access network device may issue the second radio measurement parameter to the terminal device. The terminal device may make a measurement of the signal quality of the neighboring cell based on the second radio measurement parameter. In other words, the second wireless measurement parameter may trigger the terminal device to perform inter-frequency measurement.

It is to be understood that the measurement of the signal quality of the neighbouring cell by the terminal device based on the second radio measurement parameter is a measurement in the second frequency range, i.e. a measurement of the signal quality of the neighbouring cell supporting the second frequency range and supporting the first network slice.

Thereafter, the terminal device may report the measurement result to the first access network device. It can be understood that the measurement result reported by the terminal device at this time is a measurement result obtained by measuring the signal quality of the neighboring cell in the second frequency range based on the second radio measurement parameter.

It will be appreciated that the cells reported in the measurement results are substantially all capable of providing access services for the first network slice in the second frequency range. The first access network device may determine a target cell based on the measurement. As described above, the first access network device may determine a cell whose signal quality satisfies a preset threshold as the target cell.

If the first access network device can find the target cell based on the measurement result reported by the terminal device, the first access network device may execute the subsequent step 305 to control the terminal device to switch to the target cell; otherwise, the terminal device may continue to camp in cell # 1.

It should be appreciated that the above shows the process of finding a target cell in both the intra-site neighbor cell and the extra-site neighbor cell for ease of understanding. In actual implementation, the first access network device does not have to perform all of the steps listed above. For example, the step 3042 may only need to be performed once, for example, if the target cell is found by performing the intra-frequency measurement, the inter-frequency measurement does not need to be performed; or, the cells in the same frequency range as the cell #1 are not found in the adjacent cells, and the pilot frequency measurement is directly performed; step 3042 may also need to perform two or more measurements, such as performing inter-frequency measurement after performing intra-frequency measurement; the step 3042 of the first access network device determining the target cell from the out-of-station neighboring cells supporting the target frequency range (for example, including the steps of determining and issuing the wireless measurement parameters to the terminal device, receiving the measurement result from the terminal device, and determining the target cell according to the measurement result) may not be performed, for example, the first access network device may find the cell with the same frequency range from the out-of-station neighboring cells as the target cell. This is not a limitation of the present application.

It should be noted that, for convenience of understanding and description, the process of determining the target cell by the first access network device is described in detail by taking the first session as an example. In fact, the session activated by the terminal device in the source cell may not necessarily be limited to the first session. The session activated by the terminal device in the source cell may also be multiple sessions. In this case, the target cell determined by the first access network device for the terminal device should comprehensively consider the multiple sessions, so as to ensure that the multiple sessions can be performed normally without interruption. Therefore, when the first access network device determines the target cell, it should enable, as much as possible, network slices corresponding to multiple sessions activated by the terminal device in the source cell to be supported by the target cell respectively, and all network slices can access to radio resources supported by the target cell respectively. In other words, if there is a cell in which the supported network slice includes the plurality of sessions and the plurality of network slices are all capable of accessing the same radio resource in the cell, the cell is preferentially selected as the target cell.

In step 305, the first access network device controls the terminal device to switch to the target cell.

As previously described, the target cell may or may not be the cell served by the first access network device. The terminal device may perform an intra-station handover procedure or an inter-station handover procedure. The intra-site handover procedure and the inter-site handover procedure are described in detail below.

If the target cell is a cell served by the first access network device, the terminal device may perform an in-station switching procedure.

Illustratively, the first access network device may determine the handover parameter based on radio resources supported by the target cell. The handover parameter may include, but is not limited to, an identifier of the target cell, a radio temporary identifier of the terminal device in the target cell, a carrier frequency, antenna information, beam information, a dedicated Random Access Channel (RACH) resource, a synchronization signal and a Physical Broadcast Channel (PBCH) block associated with the RACH resource, a quality of service Flow (QoS Flow), a mapping rule of a radio bearer, and the like.

Thereafter, the first access network device may issue the handover parameter to the terminal device. In one possible design, the first access network device may send the handover parameter to the terminal device through a Radio Resource Management (RRM) configuration message. The handover parameter may be used to allocate a Data Radio Bearer (DRB) for the frequency range of the first session to complete an intra-station handover of the terminal device.

It should be understood that, the specific flow of the terminal device performing the intra-station handover may refer to the prior art, and is not limited herein for the sake of brevity.

If the target cell is not the cell served by the first access network device, the terminal device may perform a cross-site handover procedure. The terminal device may be handed over from the first access network device to the second access network device. Step 305 in fig. 3 shows the cross-site handoff procedure.

Illustratively, step 305 may specifically include steps 3051-3055 described below.

In step 3051, the first access network device sends a request message to the second access network device, where the request message carries information of a session to be switched into the second access network device.

The first access network device sends a request message to the second access network device, wherein the request message is used for requesting to switch the terminal device to the second access network device. The request message may carry information of a session to be handed in to the second access network device, for example, including but not limited to identification information of the session and identification information of a network slice corresponding to the session. In the above example, the session to be handed in to the second access network device includes a first session, the network slice corresponding to the first session being a first network slice. Taking the first session as an example, the identification information of the session to be switched into the second access network device, which is carried in the request message, may include, for example, an identification of the first session or other information that can be used to identify the first session; the identification information of the network slice corresponding to the session to be handed in may be, for example, an identification of the first network slice or other information that can be used to identify the first network slice. The specific form of the identification information of the first session and the first network slice is not limited in the present application.

In step 3052, the second access network device determines an RRC parameter for handover according to information of a session to be handed in.

The second access network device may determine, according to the information of the session to be handed in, which is carried in the request message, the RRC parameter for handover by combining the network slice supported by the second access network device and the radio resource corresponding to each network slice, and the network slice corresponding to the session to be handed in, such as the first network slice. It should be understood that the RRC parameters may include, for example, the handover parameters listed above in the intra-station handover procedure. For the sake of brevity, this is not to be enumerated here.

The second access network device may also detect whether the network slice corresponding to the session to be handed in is a network slice supported by itself after receiving the request message, and further determine that the session to be handed in is allowed. For example, if the second access network device does not support a network slice for a session, hand-in to the session may be denied.

For example, the second access network device determines that it supports the first network slice corresponding to the first session, i.e. the network slice identified as S-NSSAI #1, and then prepares to accept the hand-in to the first session. And the second access network equipment determines that the first session to be switched in can be supported in both the N41 frequency band and the N79 frequency band according to the network slice marked as S-NSSAI #1 and the working frequency band corresponding to the network slice supported by the second access network equipment, including N41 and N79. And the frequency range of the first radio resource accessed by the first session in the source cell is the N41 frequency band, the second access network device preferentially allocates a Data Radio Bearer (DRB) resource to the first session to be switched in the N41 frequency band, and determines a corresponding RRC parameter.

In step 3053, the second access network device sends the RRC parameter to the first access network device.

In one implementation, the RRC parameter may be encapsulated in an RRC message container and sent to the terminal device through the first access network device. That is, the first access network device may pass through the RRC parameters from the second access network device to the terminal device.

In one possible design, the request message may be a handover request (handover request) message. The RRC parameter is carried in a handover request acknowledgement (handover request ACK) message.

In step 3054, the first access network device forwards the RRC parameter to the terminal device.

In step 3055, the terminal device accesses the radio resource of the second access network device according to the RRC parameter.

If the terminal device switches the access network device, the method may further include step 306, where the second access network device and the terminal device establish a DRB for the first session successfully switched over at the air interface, and activate the user plane of the switched-in session.

In step 307, the AMF switches the user plane path of the first session to the second access network device.

After the terminal device accesses, the second access network device may send a message to the AMF to notify the terminal device to switch to the second access network device, and notify the core network to switch the user plane path of the session switched to the second access network device by the terminal device to the second access network device. The core network then performs a path switch.

Thereafter, the terminal device may switch into a session (e.g., including the first session) with the second access network device to receive and transmit traffic data normally.

It should be understood that, the specific flow of the terminal device performing the cross-station handover may refer to the prior art, and is not limited herein for the sake of brevity.

It should also be understood that fig. 3 describes steps 305 to 307 in terms of a terminal device performing a cross-station handover as an example. This should not be construed as limiting the application in any way. In the intra-station handover procedure, the procedure involving the cross-station handover in step 305 and steps 306 and 307 are not necessarily performed.

Fig. 4 is a further schematic flow chart of a communication method provided in an embodiment of the present application. The method 400 shown in fig. 4 may include steps 401 through 419.

For ease of understanding and explanation, the scenario of method 400 is first described as follows: the terminal device in the method 400 may be a terminal device that accesses the network after being powered on, or a terminal device that initiates a registration request after moving to a new tracking area that does not belong to the original registration area, or a terminal device that periodically updates the registration with the network. The cell requested to be accessed by the terminal equipment is the cell #1 served by the first access network equipment, and the terminal equipment requests to establish one or more sessions and/or requests to activate one or more sessions in the cell # 1. In the following embodiments, an example of requesting to establish or request to activate session 1 is taken first, and then an example of requesting to establish or request to activate multiple sessions including session 1 is taken as an example to illustrate the method provided by the embodiments of the present application. It should be understood that session 1 is an example of the first session and the network slice identified as S-NSSAI #1 is an example of the first network slice.

It should also be understood that the steps performed in the following steps for requesting establishment of a session are substantially similar to the steps performed for requesting activation of a session. When the difference exists, the steps are respectively distinguished and explained for the session establishment request and the session activation request.

In addition, in this embodiment, it is assumed that the network slices supported by the first access network device and the frequency ranges corresponding to the network slices include: { S-NSSAI #2, (N41) }, the frequency range supported by the cell #1 served by the first access network device is an N41 frequency band; the network slices supported by the second access network device and the frequency ranges corresponding to the network slices include: { S-NSSAI #1, (N41, N79) }, { S-NSSAI #2, (N79) }, and { S-NSSAI #3, (N79) }.

In method 400, step 412 may correspond to step 210 in method 200, showing one possible implementation of the first access network device determining that the terminal device satisfies the cell handover condition in step 210.

Steps 413 to 414 may correspond to step 220 of the method 200, illustrating possible implementations of the first access network device determining the target cell in step 220. In step 413, the first access network device may determine the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 414, the first access network device determines a target cell according to the target frequency range. One possible implementation of step 414 is for the first access network device to determine the target cell from the intra-site neighboring cells that support the target frequency range. Another possible implementation of step 414 is to determine the target cell from the out-of-station neighboring cells that support the target frequency range. In the case where the target cell is determined from the out-of-station neighbor cells supporting the target frequency range, the method may further include: the first access network equipment determines wireless measurement parameters according to the target frequency range; the first access network equipment sends wireless measurement parameters to the terminal equipment, the wireless measurement parameters are used for measuring the signal quality of the adjacent cells by the terminal equipment, and the measurement of the signal quality of the adjacent cells by the terminal equipment is used for determining the target cell.

Step 415 may correspond to step 230 in method 200. A possible implementation of the first access network device controlling the handover of the terminal device to the target cell in step 230 is shown. Corresponding to step 414, one possible implementation manner of step 415 is that the first access network device controls the terminal device to perform intra-station handover. Another possible implementation manner of step 415 is that the first access network device controls the terminal device to perform cross-site handover. In the case of performing a cross-site handover, the method may further include: the first access network equipment sends a request message to the second access network equipment, wherein the request message carries the identification information of the first session and the identification information of the first network slice; the first access network device receiving an RRC parameter for handover from the second access network device; and the first access network equipment sends the RRC parameter to the terminal equipment. Optionally, the RRC parameter is associated with radio resources corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device.

The method 400 is described in detail below with reference to specific flow diagrams.

In step 401, the first access network device obtains configuration information of multiple access network devices from the OAM, where the configuration information of the multiple access network devices is used to indicate a network slice supported by the first access network device and a radio resource corresponding to each network slice, and a network slice supported by the access network device having an adjacent cell relationship and a radio resource corresponding to each network slice.

For example, the first access network device may receive, from the OAM, first configuration information, which may be used to indicate the network slices supported by the first access network device and the radio resources corresponding to each network slice. This process may be implemented, for example, by performing step 301 above.

The first access network device may also receive other configuration information from the OAM or from other access network devices having a neighboring cell relationship through the Xn interface, for example, receive second configuration information, where the second configuration information may be used to indicate the network slices supported by the second access network device and the radio resources corresponding to each network slice. This process may be implemented, for example, by performing step 302 above.

It should be understood that step 401 can be implemented by performing step 301 and step 302 in method 300 above, and specific contents regarding step 401 can refer to the related descriptions of step 301 and step 302 above, and are not repeated here for brevity.

In step 402, the AMF obtains configuration information for each access network device.

After the access network devices establish an N2 interface connection with the AMF, the network slices supported by the access network devices obtained in step 401 may be reported to the AMF. Optionally, each access network device may also report the network slices supported by the access network devices of the neighboring cells to the AMF. For example, the first access network device may send the first configuration information to the AMF.

Because each access network device can also obtain the configuration item information of other access network devices from the OAM or from other access network devices through the Xn interface, the AMF can also obtain the configuration information of a plurality of access network devices from a certain access network device. Optionally, the first access network device may also report configuration information of other access network devices to the AMF. For example, the first access network device may send the second configuration information to the AMF.

It should be understood that the specific implementation manner of the AMF for acquiring the configuration information of each access network device is not limited.

The AMF may determine the network slice that the tracking area or the registration area where the terminal device is currently located can access according to the network slice information supported by each access network device and the network slices supported by the access network devices of the neighboring cells. The network slice that can be accessed in the tracking area or the registration area where the terminal device is currently located may specifically refer to a network slice supported by an access network device in the tracking area or the registration area where the terminal device is currently located.

For example, the network slices supported by the first access network device and the radio resources corresponding to each network slice indicated by the first configuration information include: { S-NSSAI #2, (N41) }; the network slices supported by the second access network device and the radio resources corresponding to the network slices indicated by the second configuration information include: { S-NSSAI #1, (N41, N79) }, { S-NSSAI #2, (N79) }, and { S-NSSAI #3, (N79) }. It can be seen that the network slices supported by the first access network device include network slices identified as S-NSSAI #2 and the network slices supported by the second access network device include network slices identified as S-NSSAI #1, S-NSSAI #2, and S-NSSAI # 3. If the cell served by the first access network device and the cell served by the second access network device are in the same TA, the AMF may determine that the network slice that can be supported by the TA where the terminal device is currently located is the union { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3} of the network slices supported by the first access network device and the second access network device, instead of only the S-NSSAI #2 supported by the first access network device to which the terminal device is currently accessed.

In step 403, the terminal device sends a message requesting to establish or activate the first session to the AMF via the first access network device, where the message carries identification information of the first session.

The identification information of the first session may be, for example, an identification of the first session or other information that may be used to identify the first session. This is not a limitation of the present application. In this embodiment, the identification information of the first session may be, for example, session 1.

In one possible design, the message sent by the terminal device to the AMF requesting establishment or activation of the first session may be, for example, a registration request message. Illustratively, the terminal device may request to establish an RRC connection with the first access network device, such as sending an RRC connection establishment request to the first access network device. The terminal device may carry a registration request message to be forwarded to the AMF in the RRC connection setup request. The registration request message may further carry identification information of a session requested to be established or requested to be activated by the terminal device. The first access network device then forwards the registration request message to the AMF.

Optionally, the registration request message also carries identification information of a network slice (requested NSSAI) that the terminal device requests to access, for example, the network slice requesting to access may include a network slice identified as { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3, S-NSSAI #4, S-NSSAI #5 }.

Optionally, the registration request message also carries identification information and state information of a session that has been established by the terminal device. That is, the terminal device may have established one or more sessions that were deactivated as a result of the terminal device entering the RRC idle state prior to initiating the RRC connection establishment described above, or, in other words, prior to the last time the terminal device entered the RRC idle state. For convenience of distinction and explanation, the session that the terminal device has established is referred to as the second session. The registration request message may also carry an identifier of the second session or other information that may be used to identify the second session. The registration request message may further carry information indicating a state of the second session, so as to indicate that the second session is currently in a deactivated state.

In step 404, the AMF obtains identification information of the subscribed network slice of the terminal device from the UDM.

As mentioned above, the UDM may be used to store user data such as subscription information, authentication/authorization information, etc. The AMF may obtain subscription information of the terminal device from the UDM, where the subscription information includes identification information of a network slice subscribed by the terminal device.

One possibility is that the network slice requested by the terminal device belongs to a contracted network slice, or that the network slice requested by the terminal device is a subset of the contracted network slice. Another possibility is that some network slices previously subscribed to by the terminal device may have expired and the network slice requested by the terminal device does not belong to the subscribed network slice.

For example, in this embodiment, the network slice subscribed by the terminal device included in the subscription information includes a network slice identified as { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3, S-NSSAI #4 }. That is, the network slice identified as S-NSSAI #5 may have expired and not belong to the subscribed network slice.

In step 405, the AMF determines a network slice (allowed NSSAI) to which the terminal device is allowed to access.

The AMF may determine the network slice that the terminal device is allowed to access according to the network slice requested by the terminal device, the network slice subscribed by the terminal device, and the network slice supported by the tracking area or the registration area where the terminal device is located. The network slice requested by the terminal device may be carried in the registration request message, the network slice signed by the terminal device may be obtained from the UDM, and the network slice supported by the tracking area or the registration area where the terminal device is located may be determined based on step 402. The AMF may determine a network slice to which the terminal device is allowed to access based on the three items. In one implementation, the network slice that the terminal device is allowed to access may be determined by an intersection of the network slice requested by the terminal device, the network slice subscribed by the terminal device, and the tracking area where the terminal device is located or the network slice supported by registration.

For example, as already exemplified above, the network slice requested by the terminal device includes the network slice identified as { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3, S-NSSAI #4, S-NSSAI #5}, the network slice subscribed to by the terminal device includes the network slice identified as { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3, S-NSSAI #4}, and the network slice supported by the tracking area or the registration area where the terminal device is located includes the network slice identified as { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3 }. It may thus be determined that the network slice to which the terminal device is allowed access includes the network slice identified as S-NSSAI #1, S-NSSAI #2, S-NSSAI # 3.

It should be understood that the above step 405 may also be implemented by other network elements, such as NSSF. The AMF may send the acquired subscription information of the terminal device, the identifier information of the network slice requested by the terminal device, and the identifier information of the network slice supported by the tracking area or the registration area where the terminal device is located, which is determined in step 402, to the NSSF, and the NSSF may determine the network slice to which the terminal device is allowed to access. The NSSF may send the result to the AMF after determining the network slice to which the terminal device is allowed to access.

In step 406, the AMF determines whether to allow the session to be established or to allow the session to be activated according to the network slice to which the terminal device is allowed to access.

Based on the network slice to which the terminal device is allowed access in the above example, it may be determined that the sessions allowed to be established or the sessions allowed to be activated include session 1, session 2, and session 3. Here, the permission to establish and the permission to activate are for the request to establish and the request to activate in the above step 403, respectively. If the terminal device requests establishment of the first session in step 403, the AMF may determine that the established session is allowed in step 406; if the terminal device requests activation of the first session in step 403, the AMF may determine to allow the activated session in step 406.

In step 406, the AMF may determine whether the first session is allowed to be established or whether the first session is allowed to be activated. In this embodiment, if the first session requested to be established or activated by the terminal device is session 1, the first session is a session allowed to be established or activated, and the following steps may be continuously performed. If the first session requested to be established or activated by the terminal device is session 4, the first session does not belong to the session allowed to be established or activated. The AMF may not perform steps 407 to 410 described below but directly perform steps 411 and 412 to send identification information of a network slice to which the terminal device is allowed to access to the first access network device so that the first access network device determines that the first session is a session that is not allowed to be established or is not allowed to be activated.

In step 407, the AMF sends a Session Management (SM) context update request message or a create session management context request message to the SMF.

For the message requesting establishment of the first session in step 403, the AMF may send a create session management context request message to the SMF for requesting establishment of the first session. For the message requesting activation of the first session in step 403, the AMF may send a session management context update request message to the SMF for requesting activation of the first session.

In step 408, the SMF accepts the request for the first session establishment or the SMF accepts the request for user plane activation.

The acceptance of the request for the first session establishment by the SMF may be, for example, a step performed for a session establishment request message requesting establishment of the first session. The acceptance of the request for user plane activation by the SMF may for example be a step performed for a service request message requesting activation of the first session.

In some cases, the SMF may reselect a new UPF because the current location of the terminal device has changed from the location when the first session was established.

In step 409, the SMF establishes an N4 interface session, and controls the UPF to establish a user plane connection of the first session; or the SMF modifies the N4 interface session and controls the UPF to activate the user plane connection of the first session.

In step 410, the SMF sends a response message that the creation of the session management context is successful or a response message that the session management context update is successful to the AMF.

The response message that the creation of the session management context is successful may be, for example, a response to a session establishment request message requesting establishment of the first session. The response message that the session management context update is successful may be, for example, a response to a service request message requesting activation of the first session.

In step 411, the AMF sends identification information of the network slice to which the terminal device is allowed to access to the first access network device.

For example, the AMF may accept registration of the terminal device based on a registration request message of the terminal device, and send a message for establishing a context of the terminal device to the first access network device, where the message may carry identification information of a network slice to which the terminal device is allowed to access, a session state, and session information to be activated.

The session state may include, for example, the states of all established sessions of the terminal device in the cell # 1. In the scenario of this embodiment, the session of the terminal device in the cell #1 may include, for example, a deactivated session and a session to be activated.

The session information to be activated may specifically refer to identification information of a session requested to be activated by the terminal device and identification information of a corresponding network slice. For example, in this embodiment, the terminal device requests the identification information of the activated first session and the identification information of the corresponding first network slice.

The first access network device may determine the network slice allowed to be accessed by the terminal device according to the identification information of the network slice allowed to be accessed by the terminal device. In this embodiment, the identification information of the network slice allowed to be accessed by the terminal device may be { S-NSSAI #1, S-NSSAI #2, S-NSSAI #3} or other information that can be used to identify the network slice, for example.

Optionally, as a response to the registration request message in step 403, the message also carries a registration acceptance message to be sent to the terminal device.

In step 412, the first access network device determines that the first radio resources of cell #1 do not support the first network slice corresponding to the first session.

The first access network device may determine a first network slice corresponding to the first session according to the session information to be activated. If the network slice allowing access does not include the first network slice, the access network device may determine that the first session is a session not allowed to be established or a session not allowed to be activated. If the network slice allowing access includes the first network slice, the first access network device may further determine whether the first radio resource supports the first network slice according to the network slices supported by cell # 1.

In this embodiment, the network slice supported by the cell #1 does not include the network slice identified as S-NSSAI #1 (i.e., the network slice corresponding to the session 1, i.e., an example of the first network slice), so the first radio resource does not support the first network slice.

In step 413, the first access network device determines the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice.

Here, the frequency range corresponding to the first network slice may specifically refer to a frequency range supported by each neighboring cell supporting the first network slice, in other words, a frequency range corresponding to each neighboring cell of the first network slice. The first access network device may first determine whether the first network slice belongs to a network slice that the terminal device is allowed to access. In the case that the first network slice belongs to a network slice allowing the terminal device to access, the first access network device may further determine the target frequency range according to the frequency ranges respectively corresponding to the first network slice in the neighboring cells. Thus, step 413 may also be replaced with: the first access network device determines a target frequency range according to the network slice allowing the terminal device to access, the first network slice, the network slices supported by at least one adjacent cell and the frequency ranges corresponding to the network slices.

It should be understood that the neighboring cells of cell #1 may include cells co-located with cell #1 and cells co-located with cell # 1. In other words, the neighboring cells of cell #1 may include intra-station neighboring cells and extra-station neighboring cells. Thus, the network slice respectively supported by the at least one neighboring cell may be determined by the network slice supported by the first access network device and the network slice supported by the access network device having the neighboring cell relationship.

It is understood that there may be multiple cells in the neighboring cells of cell #1 that support the first network slice, but the radio resources corresponding to the first network slice may be different in different cells, or the corresponding frequency ranges may be different. The first access network device may preferentially select cells of the same frequency range (i.e., first frequency range) as cell # 1. Therefore, in the case that a cell supporting the first network slice and corresponding to the first frequency range exists in the neighboring cell, the first frequency range is preferentially selected as the target frequency range; otherwise, a frequency range corresponding to the first network slice supported by the neighboring cell is selected as the target frequency range, for example, the target frequency range is denoted as a second frequency range, and the second frequency range is a different frequency range from the first frequency range. In other words, the target frequency range is first the first frequency range and second the second frequency range.

In this embodiment, the first network slice is the network slice identified as S-NSSAI #1, which belongs to the network slice that the terminal device is allowed to access. In combination with the network slices respectively supported by the first access network device and the second access network device and the frequency ranges corresponding to the network slices, the first access network device does not support the network slice identified as S-NSSAI #1, and the frequency range in which the second access network device supports the network slice identified as S-NSSAI #1 includes an N41 frequency band and an N79 frequency band. And the first frequency range supported by the cell #1 is the N41 frequency band, the first access network device may preferentially select the N41 frequency band as the target frequency range, and then select the N79 frequency band (i.e., an example of the second frequency range) as the target frequency range.

In another implementation, the first access network device may determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, and the frequency ranges corresponding to the first network slice and the first network slice.

Here, the network slice of the terminal device that can be used according to the subscription may be sent by a core network device (e.g., AMF) to the first access network device, for example.

When the terminal device is in the home network, the network slice that the terminal device can use according to the subscription may refer to the network slice subscribed by the terminal device; when the terminal device is visiting the network, the network slice that the terminal device can use according to the subscription may refer to a network slice of the visiting network corresponding to the network slice subscribed by the terminal.

Since the network slice allowing the terminal device to access is determined according to the network slice subscribed by the terminal device, the network slice requested by the terminal device, and the network slice supported by the tracking area or the registration area where the terminal device is located, the two implementations may be considered as alternatives.

In step 414, the first access network device determines a target cell according to the target frequency range.

It is to be understood that the target frequency range may be the first frequency range, and may also be the second frequency range.

In one implementation, the first access network device may preferentially find the target cell from among neighboring cells within the station. Optionally, step 414 specifically includes: the first access network device determines a target cell from the intra-site neighboring cells supporting the target frequency range.

For example, the first access network device may first determine whether a cell supporting the target frequency range exists in adjacent cells in the station, for example, as the first cell. In the presence of the first cell, the first access network device may further determine whether the first cell supports the first network slice. If the first cell supports the first network slice, the first access network device may determine whether to determine the first cell as the target cell according to the signal quality of the first cell. For example, if the signal quality of the first cell meets the second preset threshold, the first cell is determined as the target cell. If the signal quality of the first cell is lower than the second preset threshold, or the first cell does not support the first network slice, or the cell #1 does not have intra-station neighboring cells (that is, the cell served by the first access network device only includes the cell #1), the first access network device may determine the target cell in the extra-station neighboring cells.

Optionally, step 414 specifically includes: the first access network device determines a target cell from the off-site neighboring cells that support the target frequency range.

Illustratively, step 414 may further comprise:

step 4141, the first access network device determines a wireless measurement parameter according to the target frequency range;

step 4142, the first access network device sends the wireless measurement parameter to the terminal device, where the wireless measurement parameter is used for the terminal device to measure the signal quality of the neighboring cell;

step 4143, the terminal device reports the measurement result of the signal quality of the adjacent cell to the first access network device;

step 4144, the first access network device determines the target cell according to the measurement result of the signal quality of the neighboring cell.

Similar to the above procedure for finding a cell from intra-station neighboring cells, the first access network device may first determine whether a first cell supporting the first frequency range is present in an extra-station neighboring cell. In the presence of the first cell, the first access network device may determine a radio measurement parameter (i.e., a first radio measurement parameter) according to the first frequency range and send the first radio measurement parameter to the terminal device, so that the terminal device may measure the signal quality of the first cell based on the first frequency range. The first access network device may further determine whether the first cell may serve as a target cell based on the measurement result reported by the terminal device. For example, when the signal quality of the first cell satisfies the second preset threshold, the first cell is determined as the target cell.

If the signal quality of the first cell is lower than the second preset threshold, the first access network device may further determine whether there are other selectable frequency ranges, and continue to search for the target cell if there are other selectable frequency ranges.

For example, if there are cells supporting the first network slice and corresponding to the second frequency range in the neighboring cells of the cell #1, the first access network device may find the target cell based on the second frequency range. The first access network device may preferentially find the target cell among the intra-station neighboring cells and secondarily find the target cell among the extra-station neighboring cells.

The specific procedure for the first access network device to find the target cell in the intra-station adjacent cell based on the second frequency range is the same as the specific procedure for the first access network device to find the target cell in the intra-station adjacent cell based on the first frequency range, described above. For brevity, no further description is provided herein.

The specific procedure of the first access network device finding the target cell in the out-of-station neighboring cell based on the second frequency range may be implemented by performing step 4141 to step 4144, which may refer to the related description above with respect to step 4141 to step 4144.

In contrast, the first access network device may determine a radio measurement parameter (i.e., a second radio measurement parameter) according to the second frequency range and send the second radio measurement parameter to the terminal device, so that the terminal device may measure the signal quality of the neighboring cell based on the second frequency range. The first access network device may further determine the target cell based on the measurement result reported by the terminal device.

It should be understood that in the case that the cell served by the first access network device only includes the cell #1, or in the case that the cell #1 does not have the intra-station neighboring cell, the first access network device may directly determine the target cell from the extra-station neighboring cells, i.e., perform the above-mentioned steps 4141 to 4144.

In addition, the radio measurement parameter (the first radio measurement parameter or the second radio measurement parameter) sent by the first access network device to the terminal device may be carried in the registration accept message forwarded by the first access network device to the terminal device, which is mentioned in step 411, for example, or may also be sent separately. This is not a limitation of the present application.

The first wireless measurement parameter and the second wireless measurement parameter may be separately sent based on different values of the target frequency range, or may be simultaneously sent to the terminal device. This is not a limitation of the present application.

It should also be understood that, for the specific process of the first access network device determining the target cell from the intra-station neighboring cell and/or the extra-station neighboring cell, reference may be made to the above description in step 304 of the method 300, and for brevity, no further description is provided here.

It should be noted that, for convenience of understanding and description, the process of determining the target cell by the first access network device is described in detail by taking the first session as an example. In fact, the session that the terminal device requests to establish or request to activate from the first access network device is not necessarily limited to the first session. The terminal device may request establishment and/or activation of multiple sessions from the first access network device in parallel. In this case, the target cell determined by the first access network device for the terminal device should comprehensively consider the multiple sessions in order to activate the multiple sessions. Therefore, when determining the target cell, the first access network device should enable, as much as possible, network slices corresponding to multiple sessions requested to be established and/or requested to be activated by the terminal device to be supported by the target cell, and all the network slices can respectively access wireless resources supported by the target cell.

In other words, if there is a cell that supports a network slice including a plurality of sessions requested to be established and/or requested to be activated by the terminal device and that is capable of accessing the same radio resource in the cell, the cell is preferentially selected as the target cell.

For example, if the session requested to be established and/or activated by the terminal device includes session 1 and session 3, the session corresponds to the network slices respectively identified as S-NSSAI #1 and S-NSSAI # 3.

As can be seen from the network slices respectively supported by the first access network device and the second access network device and the frequency ranges corresponding to the network slices, the network slice supported by the first access network device includes the network slice identified as S-NSSAI #2, and then there is no cell capable of simultaneously supporting the network slices corresponding to session 1 and session 3 in the intra-station neighboring cell of the cell # 1. And the network slices supported by the second access network device include network slices identified as S-NSSAI #1, S-NSSAI #2, and S-NSSAI #3, the target cell may be found from the off-site neighbor cell of cell # 1. The first access network device may further determine, according to the frequency range corresponding to each network slice supported by the second access network device, that the N79 frequency band may support the two network slices at the same time, so that the N79 frequency band is the target frequency range. The first access network device may look for a target cell from the off-site neighbor cell of cell #1 based on the N79 frequency band.

It will be appreciated that the above description of the process of the first access network device determining the target frequency range and hence the target cell is described in relation to a specific example for ease of understanding. It should be understood that the above illustrated correspondence relationship between each session and each network slice, the network slices supported by each access network device, the frequency ranges corresponding to each network slice, and the like are only examples, and should not constitute any limitation to the present application.

If the first access network device cannot find such a cell and can support multiple sessions requested to be established and/or requested to be activated by the terminal device, the first access network device may select a cell supporting part of the sessions as a target cell according to the load of wireless resources of each adjacent cell and the priority of each wireless resource; alternatively, the first access network device may use, as the target cell, a cell supporting a network slice corresponding to the high-priority session according to the priorities of the plurality of sessions.

As mentioned above, the terminal device may have established one or more sessions, which are deactivated, before requesting to establish an RRC connection with the first access network device. The terminal device may carry the one or more established session information when sending the RRC connection establishment request. The first access network device may further combine the one or more established sessions when determining the target cell for the terminal device, so as to support the one or more established sessions as much as possible in the selected target cell.

For example, the session currently requested to be established or requested to be activated by the terminal device includes a first session, and the corresponding network slice is a first network slice; the session which is deactivated currently by the terminal equipment comprises a second session, and the corresponding network slice is a second network slice. When the first access network device determines a target cell for the terminal device, a cell capable of supporting the first network slice and the second network slice should be selected as the target cell as much as possible.

If the first access network device cannot find a cell that can support the first network slice and the second network slice, the first network slice corresponding to the first session currently requested to be established or requested to be activated may be preferentially considered, and a cell that can support the first network slice may be selected as the target cell.

It should be understood that the various possibilities listed above are merely examples and should not be construed as limiting the present application in any way.

In step 415, the first access network device controls the terminal device to switch to the target cell.

The target cell determined by the first access network device for the terminal device may or may not be a cell served by the first access network device. The terminal device may perform an intra-station handover procedure or an inter-station handover procedure. Since the intra-site handover procedure and the inter-site handover procedure have been described in detail in step 305 of the method 300, they are not repeated here for brevity.

It should be understood that, the specific flow of the terminal device performing the cross-station handover may refer to the prior art, and for brevity, will not be described in detail here.

In step 416, the second access network device and the terminal device establish a DRB for the successfully handed over session over the air interface.

It should be understood that a successfully handed-over session may include, for example, the first session described above, or may also include both the first session and the second session described above. This is not a limitation of the present application.

In step 417, the AMF switches the user plane path of the first session to the second access network device.

In step 418, the AMF sends the N3 interface endpoint information to the second access network device.

In step 419, the second access network device establishes a user plane connection with the core network, and activates the first session.

In this embodiment, the user plane connection is also an N3 interface connection between the second access network device and the UPF. The user plane of the first session is activated based on the establishment of the N3 interface connection between the second access network device and the UPF. Thereafter, the terminal device can transceive the service data through the activated first session.

It should be understood that fig. 4 describes steps 415 to 419 as an example of the terminal device performing cross-site switching. This should not be construed as limiting the application in any way. In the intra-station handover procedure, the procedure involving the cross-station handover in step 415 and steps 416 to 419 do not necessarily have to be performed.

Based on the above technical solution, when the first session requested to be established or requested to be activated by the terminal device is not supported by the radio resource of the source cell, the first access network device serving the source cell may determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slices respectively supported by at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can be switched to the target cell in time under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell and a switchable target cell exists, so that the session request of the terminal device can be responded in time, the first session is activated in a short time, and the user experience is improved.

Fig. 5 is another schematic flow chart of a communication method provided in an embodiment of the present application. The method 500 shown in fig. 5 may include steps 501 through 515.

For ease of understanding and explanation, the scenario of method 500 is first described as follows: the terminal device in method 500 has established one or more sessions in cell #1 served by the first access network device, but some of the one or more sessions may be in a deactivated state. The terminal device and the first access network device each retain the context of the sessions without activating the user plane connection.

For ease of understanding and explanation, the present embodiment will be described below with the first session as an example of a session that is requested to be activated or requested to be established.

It should be understood that the steps performed in the following steps for requesting establishment of a session are substantially similar to the steps performed for requesting activation of a session. When the difference exists, the steps are respectively distinguished and explained for the session establishment request and the session activation request.

In addition, in this embodiment, it is assumed that the network slices supported by the first access network device and the frequency ranges corresponding to the network slices include: { S-NSSAI #2, (N41) }, the frequency range supported by the cell #1 served by the first access network device is the N41 frequency band.

In method 500, step 507 may correspond to step 210 in method 200, showing one possible implementation of the first access network device determining that the terminal device satisfies the cell handover condition in step 210.

Steps 509 and 510 may correspond to step 220 of method 200, illustrating possible implementations of the first access network device determining the target cell in step 220. In step 509, the first access network device may determine the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 510, the first access network device may determine a target cell according to the target frequency range. One possible implementation of step 510 is that the first access network device determines the target cell from the intra-site neighboring cells supporting the target frequency range. Another possible implementation of step 510 is to determine the target cell from the out-of-station neighboring cells supporting the target frequency range. In the case where the target cell is determined from an out-of-station neighbor cell supporting the target frequency range, the method may further comprise: the first access network equipment determines wireless measurement parameters according to the target frequency range; the first access network equipment sends wireless measurement parameters to the terminal equipment, the wireless measurement parameters are used for measuring the signal quality of the adjacent cells by the terminal equipment, and the measurement of the signal quality of the adjacent cells by the terminal equipment is used for determining the target cell.

Step 511 may correspond to step 230 of method 200, showing a possible implementation of the first access network device controlling the terminal device to switch to the target cell in step 230. Corresponding to step 510, one possible implementation manner of step 511 is that the first access network device controls the terminal device to perform intra-station handover. Another possible implementation manner of step 511 is that the first access network device controls the terminal device to perform cross-site handover. In the case of performing a cross-site handover, the method further includes: the first access network equipment sends a request message to the second access network equipment, wherein the request message carries the identification information of the first session and the identification information of the first network slice; the first access network device receiving an RRC parameter for handover from the second access network device; and the first access network equipment sends the RRC parameter to the terminal equipment. Optionally, the RRC parameter is associated with radio resources corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device.

The method 500 is described in detail below with reference to specific flow diagrams.

In step 501, the terminal device sends a message requesting activation or establishment of a first session to the AMF via the first access network device, where the message carries identification information of the first session requested to be activated or established.

In one possible design, the message is a service request (service request) message to request activation of the first session. Illustratively, the terminal device may send an RRC connection setup request message to the first access network device, where the RRC connection setup request message carries a service request message to be sent to the AMF, and the service request message is used to request activation of the first session. For example, the service request message may carry identification information of the first session. The first access network device then forwards the service request message to the AMF.

In another possible design, the message is a session establishment request message (session establishment request) to request establishment of the first session. The session establishment request message may also be carried in an RRC connection establishment request message to request establishment of the first session. The session establishment request may also carry identification information of the first session. The first access network device then forwards the session request message to the AMF.

In step 502, the AMF sends a session management context update request message or a create session management context request message to the SMF.

For the service request message requesting to activate the first session, the AMF sends a session management context update request message to the SMF requesting to activate the first session. For the session establishment request message requesting establishment of the first session, the AMF sends a create session management context request message to the SMF requesting establishment of the first session.

In step 503, the SMF accepts the request for user plane activation or accepts the request for first session establishment.

The receiving, by the SMF, of the request for user plane activation may be, for example, a step performed for a service request message requesting activation of the first session. The SMF acceptance of the session establishment request may be, for example, a step performed for a session establishment request message requesting establishment of the first session.

In step 504, the SMF modifies the N4 interface session, and controls the UPF to activate the user plane connection of the first session; alternatively, the SMF establishes an N4 interface session and controls the UPF to establish a user plane connection for the first session.

In step 505, the SMF sends a response message that the session management context update is successful or a response message that the session management context creation is successful to the AMF.

The response message indicating that the session management context update is successful may be, for example, a response to a service request message requesting activation of the first session. The response message that the creation of the session management context is successful may be, for example, a response to a session establishment request message requesting establishment of the first session.

In step 506, the AMF sends an N2 interface request message to the first access network device, where the N2 interface request message carries identification information of a first network slice corresponding to the first session requested to be activated or requested to be established. For example, the first session requested to be activated by the terminal device is session 1, and the corresponding first network slice is the network slice identified as S-NSSAI # 1; the first session requested to be established by the terminal device is session 2, and the corresponding first network slice is the network slice identified as S-NSSAI # 2.

In step 507, the first access network device determines that the first radio resources of cell #1 do not support the first network slice corresponding to the first session.

For example, if the first network slice corresponding to the first session is the network slice identified as S-NSSAI #2, the first radio resource of cell #1 supports the first network slice. In this case, the terminal device may continue to activate or establish the first session in the source cell, according to the prior art procedure. Since this embodiment does not involve this process, it will not be described in detail here.

For another example, if the first network slice corresponding to the first session is the network slice identified as S-NSSAI #1, the first radio resources of cell #1 do not support the first network slice. In this case, the cell #1 is a source cell of the terminal device, and the first access network device needs to determine a target cell for the terminal device.

In step 508, the first access network device suspends activating or establishing a user plane connection for the first session.

Since the first access network device determines that the first radio resource of the cell #1 does not support the first network slice corresponding to the first session, the terminal device needs to perform cell handover. Therefore, the first access network device may send indication information to the AMF for indicating handling of the handover procedure, and suspend activation or establishment of the user plane connection for the first session. After receiving the indication sent by the first access network device, the AMF may retry sending the N2 interface request message in step 506 to continue activating or establishing the user plane connection.

In step 509, the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and a frequency range corresponding to the first network slice.

It should be understood that the neighboring cells of cell #1 may include cells co-located with cell #1 and cells co-located with cell # 1. In other words, the neighboring cells of cell #1 may include intra-station neighboring cells and extra-station neighboring cells. Thus, the network slice respectively supported by the at least one neighboring cell may be determined by the network slice supported by the first access network device and the network slice supported by the access network device having the neighboring cell relationship. Therefore, the frequency range corresponding to the first network slice may specifically refer to a frequency range supported by each neighboring cell supporting the first network slice. In other words, step 509 may also be replaced with: the first access network device determines a target frequency range according to the network slice allowing the terminal device to access, the first network slice, the network slices supported by at least one adjacent cell and the frequency ranges corresponding to the network slices.

Furthermore, step 509 may also be implemented by: the first access network device may determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, and the frequency ranges corresponding to the first network slice and the first network slice. Since the detailed description of the network slice that can be used by the terminal device according to the subscription has been made above, this is not repeated here for the sake of brevity.

As previously described, the first access network device may preferentially select cells of the same frequency range (i.e., the first frequency range) as cell # 1. Therefore, in the case that a cell supporting the first network slice and corresponding to the first frequency range exists in the neighboring cell, the first frequency range is preferentially selected as the target frequency range; otherwise, another frequency range corresponding to the first network slice supported by the neighboring cell is selected as the target frequency range, for example, the other frequency range is denoted as a second frequency range, and the second frequency range is a different frequency range from the first frequency range. In other words, the target frequency range is first the first frequency range and second the second frequency range.

It should be understood that the specific process related to step 509 may refer to the description related to step 413 in method 400, and therefore, for brevity, will not be described in detail here.

In step 510, the first access network device determines a target cell according to the target frequency range.

In step 511, the first access network device controls the terminal device to switch to the target cell.

In step 512, the second access network device and the terminal device establish a DRB for the successfully handed over session over the air interface.

In step 513, the AMF switches the user plane path of the first session to the second access network device.

In step 514, the AMF sends the N3 interface endpoint information to the second access network device.

In one implementation, the AMF may send the second request message that was not sent temporarily in step 506 to the second access network device, and carry the N3 interface endpoint information in the second request message.

In step 515, the second access network device establishes a user plane connection with the core network, activating the user plane for the first session.

The specific process of steps 510 to 515 is similar to the specific process of steps 414 to 419 in method 400 above, and for brevity, is not repeated here.

It should be understood that fig. 5 describes steps 511 to 515 as an example of the terminal device performing cross-station switching. This should not be construed as limiting the application in any way. In the intra-station handover procedure, the procedure involving the cross-station handover in step 511 and steps 512 to 515 are not necessarily performed.

It should also be noted that the terminal device may have established one or more sessions, which may include an activated session and/or a deactivated session, before requesting establishment or requesting activation of the first session. The first access network device, when determining a target cell for a first session currently requesting establishment or request activation, may further incorporate one or more established sessions in an effort to support as many of the one or more established sessions as possible in the selected target cell.

For example, the session currently requested to be established or requested to be activated by the terminal device includes a first session, and the corresponding network slice is a first network slice; the currently activated session of the terminal device includes session #3 (an example of a second session), and the corresponding network slice is network slice # 3; the session currently deactivated by the terminal device includes session #4 (another example of the second session), and the corresponding network slice is network slice # 4. When the first access network device determines a target cell for the terminal device, a cell capable of supporting the first network slice, network slice #3, and network slice #4 should be selected as the target cell as much as possible.

If the first access network device cannot find a cell that can support the first network slice, the network slice #3, and the network slice #4 at the same time, the target cell may be selected according to the priority of the session, so that the selected target cell can support the higher-priority session as much as possible.

Based on the above technical solution, when the first session requested to be activated by the source cell by the terminal device cannot be supported by the radio resource of the source cell, the first access network device serving the source cell may determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slices respectively supported by at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can be switched to the target cell in time under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell and a switchable target cell exists, so that the first session can be successfully activated, the session request of the terminal device can be responded in time, and the user experience can be improved.

Fig. 6 is a further schematic flow chart of a communication method provided in an embodiment of the present application. The method 600 shown in fig. 6 may include steps 601 to 612.

For ease of understanding and explanation, the following description is first made for a scenario in which the method 600 is applicable: the terminal equipment and the first access network equipment are in an RRC connection state. The terminal device is in cell #1 served by the first access network device and has already established a session, for example, referred to as session 1, whose corresponding network slice is the network slice identified by S-NSSAI # 1. The terminal device wishes to establish a new session or wishes to activate a session, for example denoted session 3. The network slice corresponding to session 3 is the network slice identified as S-NSSAI # 3. It is to be understood that session 3 is an example of the first session and the network slice identified as S-NSSAI #3 is an example of the first network slice.

In method 600, step 602 may correspond to step 210 in method 200, showing one possible implementation of the first access network device determining that the terminal device satisfies the cell handover condition in step 210.

Steps 603 and 609 may correspond to step 220 of method 200, illustrating a possible implementation of the first access network device determining the target cell in step 220. In step 603, the first access network device may determine the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 604, the first access network device determines a target cell from the intra-site neighboring cells supporting the target frequency range. In steps 606 to 609, the first access network device determines a target cell from the out-of-station neighboring cells supporting the target frequency range. The determining the target cell from the out-of-station neighboring cells supporting the target frequency range may specifically include: step 606, the first access network device determines wireless measurement parameters according to the target frequency range; step 607, the first access network device sends the wireless measurement parameter to the terminal device; step 608, the terminal device reports the measurement result of the signal quality of at least one neighboring cell to the first access network device; and step 609, the first access network equipment determines the target cell according to the measurement result of the signal quality of at least one adjacent cell.

Step 610 may correspond to step 230 of method 200, showing a possible implementation of the first access network device controlling the handover of the terminal device to the target cell in step 230. Corresponding to step 604, the first access network device controls the terminal device to perform the intra-site handover. Corresponding to step 609, the first access network device controls the terminal device to perform cross-site handover. In the case of performing a cross-site handover, the method further includes: the first access network equipment sends a request message to the second access network equipment, wherein the request message carries the identification information of the first session and the identification information of the first network slice; the first access network device receiving an RRC parameter for handover from the second access network device; and the first access network equipment sends the RRC parameter to the terminal equipment. Optionally, the RRC parameter is associated with radio resources corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device.

The method 600 is described in detail below with reference to specific flow diagrams.

In step 601, the terminal device sends a message requesting to establish or activate the first session to the first access network device, where the message carries the identification information of the first network slice.

In one possible design, the message is a session establishment request (session establishment request) message to request establishment of the first session. For example, the terminal device may send a session establishment request message to the first access network device, where the session establishment request message may carry identification information of the first network slice. For example, the identification information of the first network slice is carried at the RRC layer of the request message. In this embodiment, the identification information of the first network slice may be S-NSSAI # 3. Since the first network slice corresponds to the first session, the request message carries an identifier of the first network slice, that is, requests to establish a session or activate a session in the first network slice by accessing the first network slice.

In another possible design, the message is a session activation request (session activation request) message to request activation of the first session. For example, the terminal device may send a session activation request message to the first access network device, where the session activation request message may carry identification information of the first network slice.

In step 602, the first access network device determines that the first radio resources of cell #1 do not support the first network slice corresponding to the first session.

The first access network device may determine whether the first radio resource supported by cell #1 supports the first network slice according to the identification information of the first network slice.

In step 603, the first access network device determines a target frequency range according to the network slice to which the terminal device is allowed to access, the first network slice, and a frequency range corresponding to the first network slice.

The network slice allowing the terminal device to access has been described in detail above in step 405 of method 400. For the sake of brevity, this is not repeated here.

The frequency range corresponding to the first network slice may specifically refer to a frequency range supported by each neighboring cell supporting the first network slice, in other words, a frequency range corresponding to each neighboring cell of the first network slice. Thus, step 602 may be replaced with: the first access network device determines a target frequency range according to the network slice allowing the terminal device to access, the first network slice, the network slices supported by at least one adjacent cell and the frequency ranges corresponding to the network slices.

The first access network device may receive, from the AMF, identification information of a network slice to which the terminal device is allowed to access and determine whether the first network slice belongs to a network slice to which the terminal device is allowed to access. In the case that the first network slice belongs to a network slice allowing the terminal device to access, the first access network device may further determine the target frequency range according to the frequency ranges respectively corresponding to the first network slice in the neighboring cells.

In another implementation, step 603 may also be replaced with: and the first access network equipment determines a target frequency range according to the network slice requested by the terminal equipment, the network slice which can be used by the terminal equipment according to the subscription, the network slice supported by the tracking area or the registration area where the terminal equipment is located, the first network slice and the frequency range corresponding to the first network slice.

It should be understood that the specific procedure for determining the target frequency range by the first access network device has been described in detail in step 410 of the method 400 above, and therefore, for brevity, will not be described in detail here.

In step 604, the first access network device determines a target cell from the intra-site neighboring cells based on the target frequency range.

The first access network device may determine whether there is a cell available as a target cell among the intra-station neighbor cells by performing step 604.

Illustratively, the first access network device may first determine whether there is a first cell supporting the target frequency range in the intra-site neighboring cells of cell # 1. In the presence of the first cell, the first access network device may further determine whether the first cell supports the first network slice. In the case where the first cell supports the first network slice, the first access network device may determine whether the first cell may be a target cell based on a signal quality of the first cell. And under the condition that the signal quality of the first cell meets a second preset threshold, the first access network equipment determines that the first cell is a target cell. Thereafter, the intra-station handover procedure in step 610 may be performed.

In a case where the intra-station neighboring cell of the cell #1 does not support the first cell, or in a case where the first cell does not support the first network slice, or in a case where the signal quality of the first cell is lower than a second preset threshold, the first access network device may determine that no cell that can be a target cell exists in the intra-station neighboring cells.

In step 605, the first access network device may send a reject message to the terminal device, suspending establishment or activating the first session.

In one implementation, the first access network device may send a rejection message to the terminal device to inform the terminal device that the first access network device rejects establishing or activating the first session.

In response to the session establishment request message in step 601 above, the first access network device may send a rejection message for the service establishment request message to the terminal device to reject establishment of the first session. In response to the session activation request message in step 601 above, the first access network device may know not to send a rejection message for the session activation response message to reject activation of the first session.

In step 606, the first access network device determines a radio measurement parameter according to the target frequency range.

In step 607, the first access network device transmits the radio measurement parameters to the terminal device.

In one implementation, the radio measurement parameter may be carried in the reject message to trigger the terminal device to measure the signal quality of at least one neighboring cell.

In step 608, the terminal device measures the signal quality of the at least one neighboring cell based on the wireless measurement parameter, and reports the measurement result of the signal quality of the at least one neighboring cell to the first access network device.

In step 609, the first access network device determines a target cell according to the measurement result of the signal quality of at least one neighboring cell.

The target cell thus determined by the first access network device is a target cell determined from an off-site neighbor cell. The terminal device needs to switch the access network device.

As an example, the first session that the terminal device requests to establish is session 3, and the first network slice is the network slice identified as S-NSSAI # 3. Assuming that the network slices supported by the first access network device and the frequency ranges corresponding to the network slices include: { S-NSSAI #1, (N41) } and { S-NSSAI #2, (N41, N79) }, the network slices supported by the second access network device and the frequency ranges corresponding to the network slices include: { S-NSSAI #1, (N41, N79) }, { S-NSSAI #2, (N79) }, and { S-NSSAI #3, (N79) }.

It can be seen that the identity of the network slice supported by the first access network device does not include S-NSSAI #3, and there is no cell capable of supporting the network slice of session 3 in the intra-site neighbor cell of this cell # 1. And the identity of the network slice supported by the second access network device includes S-NSSAI #3, then the cell of the out-of-station neighbor cell of this cell #1 exists a cell capable of supporting the network slice of session 3. The first access network device may find a target cell from the off-site neighbor cells of cell # 1. The first access network device may further determine, according to the frequency range corresponding to the network slice, that the frequency range corresponding to the network slice identified as S-NSSAI #3 in the second access network device is the N79 frequency band, so that the target frequency range is the N79 frequency band. Thereafter, the first access network device may look for a target cell from the off-site neighbor cell of cell #1 based on the N79 frequency band. The target cell is capable of providing access service for the network slice identified as S-NSSAI #3 in the N79 frequency band.

Further, if the terminal device has already established session 1 in cell #1, the corresponding network slice is the network slice identified as S-NSSAI # 1. The first access network device may determine the target frequency range in conjunction with the network slices corresponding to session 1 and session 3, respectively. If session 1 corresponds to the network slice identified as S-NSSAI #1, session 3 corresponds to the network slice identified as S-NSSAI #3, and the common frequency range corresponding to the second access network device is the N79 frequency band, the target frequency range is the N79 frequency band. Thereafter, the first access network device may look for a target cell from the off-site neighbor cell of cell #1 based on the N79 frequency band. The target cell is capable of providing access services in the N79 band for network slices identified as S-NSSAI #1 and S-NSSAI # 3.

It will be appreciated that the above description of the process of the first access network device determining the target frequency range and hence the target cell is described in relation to a specific example for ease of understanding. The correspondence between each session and each network slice, the network slices supported by each access network device, the frequency ranges corresponding to each network slice, and the like in this document are merely examples, and should not limit the present application in any way.

It should also be understood that, in the case that there are multiple sessions that are requested to be established and/or activated, the details of determining, by the first access network device, the target cell for the terminal device have been described in detail in the above method 400 and method 500, and are not described herein again for brevity.

It should also be understood that, in the case that there are one or more established sessions (for example, including activated and/or deactivated sessions) in the terminal device, the details of determining, by the first access network device, the relevant content of the target cell for the terminal device have also been described in the above method 400 and method 500, and are not described herein again for brevity.

In step 610, the first access network device controls the terminal device to switch to the target cell.

As mentioned above, the first access network device may control the terminal device to perform an intra-site handover procedure or may control the terminal device to perform a cross-site handover procedure, depending on whether the target cell is a cell served by the first access network device. It should be understood that, since the detailed description has been made in the step 305 of the above method 300 in conjunction with the intra-station handover procedure and the cross-station handover procedure, respectively, and the specific procedures of the terminal device for performing the intra-station handover and the cross-station handover may refer to the prior art, the detailed description is not provided here for brevity.

In step 611, the terminal device sends a message requesting to establish or activate the first session to the second access network device, where the message carries identification information of the first network slice corresponding to the first session.

The message sent by the terminal device to the second access network device is similar to the message sent by the terminal device to the first access network device in step 601, which requests establishment or activation of the first session, where the RRC layer carries the identification information of the first network slice. The request message is for requesting establishment or activation of a first session.

In step 612, the terminal device initiates a session establishment procedure through the second access network device.

Thereby, the first session is successfully established. The terminal equipment can normally transmit the service data through the first session.

It should be appreciated that step 612 need not be performed based on a different scenario in which a first session is requested to be established or requested to be activated. For example, in a scenario where activation of the first session is requested, step 612 may be omitted. The terminal device completes activation of the first session after the handover to the second access network device.

It should also be understood that the various steps shown above are not necessarily performed. For example, if the target cell is the intra-site neighboring cell of the cell #1, the above steps 604 to 608 to 611 are not necessarily performed.

Based on the above technical solution, when the first session requested to be established by the source cell by the terminal device cannot be supported by the radio resource of the source cell, the first access network device serving the source cell may determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slices respectively supported by at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can timely switch the terminal device to the target cell under the condition that the first session requested to be established is not supported by the radio resource of the source cell and the switchable target cell exists, so that the first session can be successfully established and activated, the session request of the terminal device can be timely responded, and the user experience can be improved.

Fig. 7 is a further schematic flow chart of a communication method provided in an embodiment of the present application. The method 700 shown in fig. 7 may include steps 701 through 713.

The method 700 is applicable in the same scenario as the method 600, and reference may be made to the scenario described in the method 600 above. For the sake of brevity, this is not repeated here. Stated differently, in method 700, a terminal device requests establishment of a first session.

In method 700, step 706 may correspond to step 210 in method 200, showing one possible implementation of the first access network device determining that the terminal device satisfies the cell handover condition in step 210.

Steps 707 and 709 may correspond to step 220 of the method 200, showing possible implementations of the first access network device determining the target cell in step 220. In step 707, the first access network device may determine the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 709, the first access network device determines a target cell according to the target frequency range. One possible implementation of step 709 is that the first access network device determines the target cell from the intra-site neighboring cells supporting the target frequency range. Another possible implementation of step 709 is to determine the target cell from the out-of-station neighboring cells supporting the target frequency range. In the case where the target cell is determined from an out-of-station neighbor cell supporting the target frequency range, the method may further comprise: the first access network equipment determines wireless measurement parameters according to the target frequency range; the first access network equipment sends wireless measurement parameters to the terminal equipment, the wireless measurement parameters are used for measuring the signal quality of the adjacent cells by the terminal equipment, and the measurement of the signal quality of the adjacent cells by the terminal equipment is used for determining the target cell.

Step 710 may correspond to step 230 of method 200, showing a possible implementation of the first access network device controlling the handover of the terminal device to the target cell in step 230. Corresponding to step 709, in a possible implementation manner of step 710, the first access network device controls the terminal device to perform intra-station handover. Another possible implementation manner of step 710 is that the first access network device controls the terminal device to perform cross-site handover. In the case of performing a cross-site handover, the method further includes: the first access network equipment sends a request message to the second access network equipment, wherein the request message carries the identification information of the first session and the identification information of the first network slice; the first access network device receiving an RRC parameter for handover from the second access network device; and the first access network equipment sends the RRC parameter to the terminal equipment. Optionally, the RRC parameter is associated with radio resources corresponding to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device.

The method 700 is described in detail below with reference to specific flow diagrams.

In step 701, the terminal device sends a message requesting to establish the first session to the AMF via the first access network device, where the message carries identification information of the first session.

In one implementation, the terminal device may carry the identification information of the first session in a message sent to the first access network device, but not carry the identification information of the first network slice. The first access network device may forward the session establishment request message to the AMF. In this embodiment, the identification information of the first session may be, for example, session 3.

In one possible design, the message is a session setup request message, as described in method 600.

In step 702, AMF and SMF create a session management (SM context) context for the first session requested to be established.

For example, the AMF may select an SMF and create a session management context for the first session with the selected SMF.

In step 703, the SFM and the UPF establish an N4 interface session.

For example, the SMF may select a UPF and send an N4 session establishment request to the selected UPF to request establishment of an N4 session.

In step 704, the SMF sends identification information of the first network slice to the AMF.

The SMF may send an N1N2 transfer message (N1N2 message transfer) to the AMF, which carries N2 session management information (N2 SM information). The N2 session management information includes information of the newly created session, including identification information of the first network slice corresponding to the first session. In this embodiment, the identification information of the first network slice may be S-NSSAI # 3.

In step 705, the AMF sends identification information of the first network slice to the first access network device.

The AMF may forward the N2 session management information to the first access network device based on the received N2 session management information. As described above, the N2 session management information carries the identification information of the first network slice. Thus, the first access network device may determine a first network slice corresponding to the first session requested to be established by the terminal device.

In one possible design, the N2 session management information is carried in an N2 interface request message.

In step 706, the first access network device determines that the first radio resource of the cell #1 in which the terminal is currently located does not support the first network slice corresponding to the first session.

In step 707, the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and an operating frequency corresponding to the first network slice.

In another implementation, step 707 may also be replaced with: and the first access network equipment determines a target frequency range according to the network slice requested by the terminal equipment, the network slice which can be used by the terminal equipment according to the subscription, the network slice supported by the tracking area or the registration area where the terminal equipment is located, the first network slice and the frequency range corresponding to the first network slice. It should be understood that the specific procedure for determining the target frequency range by the first access network device has been described in detail in step 413 of the method 400 above, and therefore, for brevity, will not be described in detail here.

In step 708, the first access network device determines that the current operating frequency range of the terminal device is different from the target frequency range, and sends indication information for indicating to process the handover procedure to the AMF.

The currently operating frequency range of the terminal device refers to a frequency range corresponding to the first radio resource of the cell #1 where the terminal device is currently located, that is, a frequency range supported by the cell # 1. And if the current working frequency range of the terminal equipment is inconsistent with the target frequency range, determining that the terminal equipment needs to perform cell switching. Therefore, the first access network device may suspend the DRB allocation for the first session and send the indication information for indicating the handover procedure to the AMF. After receiving the indication information sent by the first access network device, the AMF may retry to send the N2 interface request message in step 705 at a later time, and continue to establish the user plane connection.

In step 709, the first access network device determines a target cell according to the target frequency range.

Optionally, step 709 specifically includes: the first access network device determines a target cell from the intra-site neighboring cells supporting the target frequency range.

Illustratively, the first access network device may first determine whether there is a first cell supporting the target frequency range in the intra-site neighboring cells of cell # 1. In the presence of the first cell, the first access network device may further determine whether the first cell supports the first network slice. In the case where the first cell supports the first network slice, the first access network device may determine whether the first cell may be a target cell based on a signal quality of the first cell. And under the condition that the signal quality of the first cell meets a second preset threshold, the first access network equipment determines that the first cell is a target cell. Thereafter, the intra-station handover procedure in step 714 may be performed.

Optionally, step 709 specifically includes: the first access network device determines a target cell from the off-site neighboring cells that support the target frequency range.

In a case where the intra-station neighboring cell of the cell #1 does not support the first cell, or the first cell does not support the first network slice, or the signal quality of the first cell is lower than the second preset threshold, or the cell served by the first access network device includes only the cell #1, the first access network device may determine that there is no cell that can be a target cell among the intra-station neighboring cells. The first access network device may thereby determine the target cell among the off-site neighbor cells.

The specific process of the first access network device determining the target cell in the out-of-station neighboring cells has been described in detail in step 411 of the method 400 above, and for brevity, no further description is given here.

It should be understood that, in the case that there are multiple sessions requested to be established, the details of determining, by the first access network device, the relevant content of the target cell for the terminal device have been described in the above method 400 and method 500, and are not described herein again for brevity.

In step 710, the first access network device controls the terminal device to switch to the target cell.

In step 711, the AMF performs path switching to switch the terminal device to the second access network device.

In an implementation manner, the second access network device may send a handover completion message to the AMF based on completion of air interface handover with the terminal device, or send a path handover message to the AMF. The AMF may perform path switching based on a message from the second access network device.

In step 712, the AMF resends the N2 interface request message from step to the second access network device, continuing to establish the user plane connection for the newly created first session.

In step 713, the second access network device allocates a DRB for the newly created first session in the frequency range supported by the target cell.

The frequency range supported by the target cell is the target frequency range. The second access network device may assign a DRB for the first session at the target frequency range. And may send a session establishment accept message to the terminal device.

In one possible design, the session establishment accept message may be carried in AN access network-specific resource setup (AN-specific resource setup) message.

After the first session is successfully established, the terminal device may transmit the service data through the first session.

It should be understood that not all of the various steps shown above are to be performed. For example, if the target cell is an intra-station neighboring cell of the cell #1, the above partial steps (steps related to the inter-station handover procedure) in step 710 and steps 711 to 713 need not be executed.

Based on the above technical solution, when the first session requested to be established by the source cell by the terminal device cannot be supported by the radio resource of the source cell, the first access network device serving the source cell may determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slices respectively supported by at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can timely switch the terminal device to the target cell under the condition that the first session requested to be established is not supported by the radio resource of the source cell and the switchable target cell exists, so that the first session can be successfully established, the session request of the terminal device can be timely responded, and the user experience can be improved.

Fig. 8 is a further schematic flow chart of a communication method provided in an embodiment of the present application. The method 800 shown in fig. 8 may include steps 810 through 820.

In step 810, the first access network device determines that the first radio resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session requested to be established or requested to be activated by the terminal device.

In step 820, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

In step 810, the session requested to be established or activated by the terminal device in the source cell is recorded as a first session, and the network slice corresponding to the first session is recorded as a first network slice. The first wireless resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session, which may specifically mean that a frequency range provided by the first wireless resource does not support the first network slice, or that the source cell does not support the first network slice. Therefore, the frequency range provided by the source cell cannot provide the access service for the first network slice corresponding to the first session requested to be established or activated by the terminal device.

One possible scenario is that the terminal device accesses the network after being powered on, or initiates a registration request to the network because it moves to a new TA that does not belong to the original registration area. Or when the terminal equipment periodically updates the registration to the network, the terminal equipment initiates a registration request to the network. The terminal device may carry a session list requesting establishment or activation in the registration request. The session list includes identification information of sessions requested to be established and/or activated by the terminal device. The session that the terminal device requests to establish or requests to activate may include, for example but is not limited to, the first session.

Another possible scenario is that the terminal device desires to establish a new session. The terminal device may send a session establishment request message to the first access network device to request establishment of one or more sessions. The one or more sessions that the terminal device requests to be established may include, for example, but are not limited to, the first session.

In the above possible scenarios, if the first access network device determines that the first radio resource does not support the first network slice corresponding to the first session requested to be established or requested to be activated by the terminal device, it may determine that the terminal device is not suitable to continue to reside in the cell #1, and therefore step 220 may be performed to release the RRC connection with the terminal device.

The terminal device enters an idle state based on the RRC connection release between the terminal device and the first access network device, and then cell selection can be carried out again so as to select a proper cell and initiate an RRC connection request.

Based on the above technical solution, the first access network device may actively release the RRC connection with the terminal device when the first radio resource accessed by the terminal device does not support the first network slice of the first session requested to be established or requested to be activated, so that the terminal device may quickly enter an idle state to initiate cell reselection. And the idle state is not required to be entered after the current service is finished. Therefore, the terminal device can perform cell reselection in time under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell, so that the first session requested to be established or requested to be activated by the terminal device is successfully activated, and the request of the terminal device can be responded in time, thereby being beneficial to improving user experience.

Since the following will describe the specific process of applying the communication method 800 provided by the present application to the above scenario in conjunction with fig. 9 and 10, the detailed description is omitted here for brevity.

Fig. 9 is a further schematic flow chart of a communication method provided in an embodiment of the present application. Method 900 shown in fig. 9 may include steps 901 through 921.

The process applicable to the method 900 is the same as the scenario applicable to the method 400, and for brevity, the description is omitted here.

In method 900, step 907 may correspond to step 810 in method 800, and step 911 may correspond to step 820 in method 800. Optionally, the RRC connection release message sent by the first access network device to the terminal device in step 911 may carry radio parameters for cell reselection. Optionally, before step 911, the method further comprises: step 910, the first access network device determines a radio parameter according to the target frequency range, the network slice supported by at least one neighboring cell, and the frequency range corresponding to each network slice.

It should be understood that the related descriptions of the steps of the method 900 for establishing the session and activating the session can refer to the related descriptions in the above embodiments, and are not repeated here for brevity.

In step 901, the terminal device sends identification information requesting establishment of or activation of a first session to the AMF via the first access network device.

In step 902, the AMF obtains the identification information of the network slice of the subscription information of the terminal device from the UDM.

In step 903, the AMF determines a network slice to which the terminal device is allowed to access.

In step 904, the AMF determines whether to allow establishment or to allow an active session based on the network slice to which the terminal device is allowed to access.

In step 905, the SMF establishes an N4 interface session, and controls the UPF to establish a user plane connection of the first session; alternatively, the SMF modifies the N4 interface session and controls the UPF to activate the user plane connection for the first session.

In step 906, the AMF sends identification information of the network slice to which the terminal device is allowed to access to the first access network device.

In step 907, the first access network device determines that the first radio resource of the cell #1 where the terminal is currently located does not support the first network slice corresponding to the first session.

In step 908, the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and a frequency range corresponding to the first network slice.

Alternatively, step 908 may also be implemented by: the first access network device may determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, and the frequency ranges corresponding to the first network slice and the first network slice.

It should be understood that the specific processes of steps 901 to 908 can refer to the above description related to steps 403 to 410 in the method 400, and are not repeated here for brevity.

In step 909, the first access network device determines that the frequency range in which the terminal device is currently operating is different from the target frequency range.

The frequency range in which the terminal device currently operates is a frequency range supported by the cell #1 in which the terminal device currently exists, or a frequency range corresponding to the first radio resource of the cell # 1. If the current operating frequency range of the terminal device is different from the target frequency range, it indicates that the first radio resource of the cell #1 does not support the first network slice.

In step 910, the first access network device determines a radio parameter according to the target frequency range, the network slice of at least one neighboring cell, and the frequency range corresponding to each network slice.

The radio parameters may be used for cell reselection by the terminal device. For example, an indication of the target frequency range may be included in the radio parameters, and the terminal device may preferentially reselect cells supporting the target frequency range based on the indication.

In step 911, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

The first access network device decides to suspend the first session distribution DRB requested to be established or requested to be activated for the terminal device based on that the cell #1 does not support the first network slice, and at the same time decides to release the RRC connection with the terminal device, deactivating all already established sessions of the terminal device. Therefore, the terminal equipment directly enters an idle state to perform cell reselection, and does not need to enter the idle state after the current service is completed.

In one implementation, the radio parameters determined by the first access network device in step 910 may be carried in the RRC connection release message. That is, step 910 may be performed before step 911. In another implementation, the radio parameters may be sent to the terminal device through other signaling. In this case, the sequence of executing steps 910 and 911 is not limited.

In one possible design, the identification information of the first session requested to be established or requested to be activated in step 901 may be carried in a registration request message sent by the terminal device to the AMF. The identification information of the network slice allowed to be accessed by the terminal device in step 906 may be carried in a registration accept message sent by the AMF to the first access network device. The RRC connection release message in step 910 may be carried in a registration accept message forwarded by the first access network device to the terminal device.

In step 912, the terminal device deactivates all sessions and enters an idle state.

The terminal device can access the idle state based on the RRC connection release message received in step 911.

In step 913, the terminal device performs cell reselection based on the radio parameters to determine that the re-accessed access network device is the second access network device.

The terminal device may perform cell reselection in an idle state based on the radio parameter delivered by the first access network device. The terminal device may first find a suitable cell in the target frequency range, which may be understood as the target cell in the above embodiments, based on the radio parameters, i.e. the cell may provide the access service of the first network slice in the target frequency range, or the radio resources provided by the cell support the first network slice. The terminal device may determine the re-accessed access network device based on the access network device to which the cell belongs.

The terminal device determines the re-accessed access network device to be the second access network device based on the cell reselection.

In step 914, the terminal device initiates an RRC connection to the second access network device, and sends a message requesting to establish or request to activate the first session, where the message carries identification information of the first session requesting to establish or request to activate.

In a possible design, the identification information of the first session that the terminal device requests to establish or request to activate may be carried in a service request (service request) message. The terminal device may send an RRC connection request message to the second access network device, and carry a service request message in the RRC connection request message to request establishment or activation of the first session.

In step 915, the second access network device sends a message requesting to establish or activate the first session to the AMF, where the message carries the identification information of the first session.

The second access network device may forward the message requesting establishment or requesting activation to the AMF via an N2 interface message in step 915. In response to the service request message received in step 914, the second access network device may forward the service request message to the AMF.

In step 916, the AMF sends a create session management context request message to the SMF or the AMF sends a session management context update request message to the SMF.

In step 917, the SMF accepts the request for the first session establishment, or the SMF accepts the request for user plane activation. The SMF may also reselect a new UPF due to the terminal device accessing a new access network device.

In step 918, the SMF establishes an N4 interface session, and controls the UPF to establish a user plane connection of the first session; alternatively, the SMF modifies the N4 interface session and controls the UPF to activate the user plane connection for the first session.

In step 919, the SMF sends a response message to the AMF that the creation of the session management context was successful, or the SMF sends a response message to the AMF that the update of the session management context was successful.

In step 920, the AMF sends an N2 interface request message to the second access network device, where the N2 interface request message carries information of the first session, where the information includes identification information of the first network slice corresponding to the first session.

In step 921, the second access network device establishes a DRB for the terminal device in the target frequency range according to the first network slice corresponding to the first session, and connects to the user plane of the first session.

Thereby, the first session is successfully activated. The terminal device may transmit the service data through the first session.

Based on the above technical solution, when the first session requested to be established or requested to be activated by the terminal device in the source cell cannot be supported by the radio resource of the source cell, the first access network device serving the source cell may directly release the RRC connection with the terminal device, so that the terminal device enters an idle state to perform cell reselection, and does not need to enter the idle state after the current service of the terminal device is completed. Therefore, the terminal device can perform cell reselection in time under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell, so that the first session requested to be established or requested to be activated by the terminal device is successfully activated, and the request of the terminal device can be responded in time, thereby being beneficial to improving user experience.

Fig. 10 is a further schematic flow chart of a communication method provided in an embodiment of the present application. The method 1000 shown in fig. 10 may include steps 1001 through 1020.

The process applicable to the method 1000 is the same as the scenario applicable to the method 600, and is not described herein again for brevity.

In method 1000, step 1006 may correspond to step 810 in method 800, and step 1010 may correspond to step 820 in method 800. Optionally, the RRC connection release message sent by the first access network device to the terminal device in step 1010 may carry radio parameters for cell reselection. Optionally, before step 1010, the method further comprises: step 1009, the first access network device determines the radio parameters according to the target frequency range, the network slices respectively supported by at least one neighboring cell, and the frequency ranges corresponding to the network slices.

It should be understood that the related descriptions of the steps of the method 1000 regarding the establishment of the session and the activation of the session can refer to the related descriptions in the above embodiments, and are not repeated here for brevity.

In step 1001, the terminal device sends a message requesting to establish or activate a first session to the AMF via the first access network device, where the message carries identification information of the first session.

In step 1002, the AMF and SMF create a session management context for the first session requested to be established, or update the session management context.

In step 1003, the SMF and UPF establish an N4 interface session or modify an N4 interface session.

In step 1004, the SMF sends identification information of the first network slice to the AMF.

In step 1005, the AMF sends the identification information of the first network slice to the first access network device.

In step 1006, the first access network device determines that the first radio resource of the cell #1 in which the terminal is currently located does not support the first network slice corresponding to the first session.

In step 1007, the first access network device determines a target frequency range according to the network slice to which the terminal device is allowed to access, the first network slice, and an operating frequency corresponding to the first network slice.

Alternatively, step 1007 can also be implemented by: the first access network device may determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, and the frequency ranges corresponding to the first network slice and the first network slice.

It should be understood that the specific processes of steps 1001 through 1007 may refer to the above description related to steps 701 through 707 in method 700, and are not repeated here for brevity.

In step 1008, the first access network device determines that the frequency range in which the terminal device is currently operating is different from the target frequency range.

In step 1009, the first access network device determines the radio parameters according to the network slices of the at least one neighboring cell of the first frequency and the frequency ranges corresponding to the network slices.

In step 1010, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

In step 1011, the terminal device deactivates all sessions and enters an idle state.

In step 1012, the terminal device performs cell reselection based on the radio parameters to determine that the re-accessed access network device is the second access network device.

In step 1013, the terminal device initiates an RRC connection to the second access network device and sends identification information of the first session requested to be established.

In step 1014, the second access network device sends the identification information of the first session to the AMF.

In step 1015, the AMF sends a create session management context request message to the SMF, or the AMF sends a session management context update request message to the SMF.

In step 1016, the SMF accepts the request for the first session establishment, or the SMF accepts the request for user plane activation. The SMF may also reselect a new UPF due to the terminal device accessing a new access network device.

In step 1017, the SMF establishes an N4 interface session, and controls the UPF to establish a user plane connection of the first session; or the SMF modifies the N4 interface session and controls the UPF to activate the user plane connection of the first session.

At step 1018, the SMF sends a response message to the AMF that the creation of the session management context was successful, or the SMF sends a response message to the AMF that the update of the session management context was successful.

In step 1019, the AMF sends an N2 interface request message to the second access network device, where the N2 interface request message carries information of the first session, where the information includes identification information of the first network slice corresponding to the first session.

In step 1020, the second access network device establishes a DRB for the terminal device in the target frequency range according to the first network slice corresponding to the first session, and connects to the user plane of the first session.

Thereby, the first session is successfully established and activated. The terminal device may transmit the service data through the first session.

It should be understood that the specific process of steps 1008 through 1020 may refer to the above description related to steps 909 through 921 in method 900, and for brevity, will not be repeated here.

Based on the above technical solution, when the first session requested to be established or requested to be activated by the terminal device in the source cell cannot be supported by the radio resource of the source cell, the first access network device serving the source cell may directly release the RRC connection with the terminal device, so that the terminal device enters an idle state to perform cell reselection, and does not need to enter the idle state after the current service of the terminal device is completed. Therefore, the terminal device can perform cell reselection in time under the condition that the first session requested to be established or requested to be activated is not supported by the radio resource of the source cell, so that the first session requested to be established by the terminal device is successfully established and activated, and the request of the terminal device can be responded in time, thereby being beneficial to improving user experience.

It is to be understood that in the above embodiments, each network element may perform some or all of the steps in each embodiment. These steps or operations are merely examples, and other operations or variations of various operations may be performed by embodiments of the present application. Further, the various steps may be performed in a different order presented in the embodiments, and not all of the operations in the embodiments of the application may be performed. The sequence number of each step does not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic of the process, and should not be limited in any way to the implementation process of the embodiment of the present application.

The communication method provided by the embodiment of the present application is described in detail above with reference to fig. 2 to 10. Hereinafter, a communication device according to an embodiment of the present application will be described in detail with reference to fig. 11 to 13.

Fig. 11 is a schematic block diagram of a communication device provided in an embodiment of the present application. As shown in fig. 11, the communication apparatus 2000 may include a determination unit 2100, a control unit 2200, and a transceiving unit 2300.

Alternatively, the communication device 2000 may correspond to the first access network device in the above method embodiment, and may be, for example, the first access network device, or a component (e.g., a circuit, a chip, or a system-on-chip, etc.) configured in the first access network device.

It should be understood that the communication apparatus 2000 may correspond to the first access network device in the methods 200 to 1000 according to the embodiments of the present application, and the communication apparatus 2000 may include means for performing the methods performed by the first access network device in the methods 200 to 1000 in fig. 2 to 10. Also, the units and other operations and/or functions described above in the communication device 2000 are respectively for implementing the corresponding flows of the method 200 in fig. 2 to the method 1000 in fig. 10.

It should be understood that when the communication apparatus 2000 is a first access network device, the transceiving unit 2300 in the communication apparatus 2000 may be implemented by a transceiver, for example, may correspond to the transceiver 3020 in the communication apparatus 3000 shown in fig. 12 or the RRU 4100 in the base station 4000 shown in fig. 13. The determining unit 2100 and the control unit 2200 in the communication apparatus 2000 may be implemented by at least one processor, for example, may correspond to the processor 3010 in the communication apparatus 3000 shown in fig. 12 or the processing unit 4200 or the processor 4202 in the base station 4000 shown in fig. 13.

It should also be understood that, when the communication device 2000 is a chip or a chip system configured in the first access network equipment, the transceiving unit 2300 in the communication device 2000 may be implemented by an input/output interface, a circuit, etc., and the determining unit 2100 and the control unit 2200 in the communication device 2000 may be implemented by a processor, a microprocessor, an integrated circuit, etc., integrated on the chip or the chip system.

Fig. 12 is another schematic block diagram of a communication device 3000 provided in an embodiment of the present application. As shown in fig. 12, the communication device 3000 includes a processor 3010, a transceiver 3020, and a memory 3030. Wherein, the processor 3010, the transceiver 3020 and the memory 3030 are in communication with each other via an internal connection path, the memory 3030 is configured to store instructions, and the processor 3010 is configured to execute the instructions stored in the memory 3030 to control the transceiver 3020 to transmit and/or receive signals.

It should be understood that the communication device 3000 may correspond to the first access network apparatus in the above method embodiments, and may be configured to perform each step and/or flow performed by the first access network apparatus in the above method embodiments. Alternatively, the memory 3030 may include both read-only memory and random access memory, and provide instructions and data to the processor. The portion of memory may also include non-volatile random access memory. The memory 3030 may be a separate device or may be integrated in the processor 3010. The processor 3010 may be configured to execute the instructions stored in the memory 3030, and when the processor 3010 executes the instructions stored in the memory, the processor 3010 is configured to perform the steps and/or procedures corresponding to the first access network device in the foregoing method embodiments.

Optionally, the communication device 3000 is the first access network device in the previous embodiment.

The transceiver 3020 may include a transmitter and a receiver, among others. The transceiver 3020 may further include an antenna, and the number of antennas may be one or more. The processor 3010 and the memory 3030 may be devices integrated on different chips than the transceiver 3020. For example, the processor 3010 and the memory 3030 may be integrated in a baseband chip, and the transceiver 3020 may be integrated in a radio frequency chip. The processor 3010 and the memory 3030 may also be devices integrated on the same chip as the transceiver 3020. This is not a limitation of the present application.

Optionally, the communication device 3000 is a component configured in the first access network device, such as a circuit, a chip system, and the like.

The transceiver 3020 may also be a communication interface, such as an input/output interface, a circuit, and the like. The transceiver 3020 and the processor 3010 and the memory 3030 may be integrated in the same chip, such as a baseband chip.

Fig. 13 is a schematic structural diagram of a network device provided in the embodiment of the present application, which may be a schematic structural diagram of a base station, for example. The base station 4000 may be applied to the system shown in fig. 1, and performs the functions of the first access network device in the above method embodiment.

As shown, the base station 4000 may include one or more radio frequency units, such as a Remote Radio Unit (RRU) 4100 and one or more baseband units (BBUs) (also referred to as Distributed Units (DUs)) 4200. The RRU 4100 may be referred to as a transceiver unit, and may correspond to the transceiver unit 2300 in fig. 11 or the transceiver 3020 in fig. 12. Optionally, the RRU 4100 may also be referred to as a transceiver, transceiver circuitry, or transceiver, etc., which may include at least one antenna 4101 and a radio frequency unit 4102. Optionally, the RRU 4100 may include a receiving unit and a sending unit, where the receiving unit may correspond to a receiver (or called receiver, receiving circuit), and the sending unit may correspond to a transmitter (or called transmitter, transmitting circuit). The RRU 4100 is mainly used for transceiving and converting radio frequency signals and baseband signals, for example, for sending radio measurement parameters, RRC connection release messages, and the like to a terminal device. The BBU4200 is mainly used for performing baseband processing, controlling a base station, and the like. The RRU 4100 and the BBU4200 may be physically disposed together or may be physically disposed separately, that is, distributed base stations.

The BBU 4200 is a control center of the base station, and may also be referred to as a processing unit, and may correspond to the determining unit 2100 and the control unit 2200 in fig. 11 or the processor 3010 in fig. 12, and is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulating, spreading, and the like. For example, the BBU (processing unit) may be configured to control the base station to perform the operation procedures of the above method embodiments with respect to the first access network device, for example, determining a target frequency range, determining a target cell, and the like.

In an example, the BBU 4200 may be formed by one or more boards, and the multiple boards may collectively support a radio access network of a single access system (e.g., an LTE network), or may respectively support radio access networks of different access systems (e.g., an LTE network, a 5G network, or other networks). The BBU 4200 further includes a memory 4201 and a processor 4202. The memory 4201 is used to store necessary instructions and data. The processor 4202 is configured to control the base station to perform necessary actions, for example, to control the base station to perform the operation procedure related to the network device in the above method embodiment. The memory 4201 and the processor 4202 may serve one or more boards. That is, the memory and processor may be provided separately on each board. Multiple boards may share the same memory and processor. In addition, each single board can be provided with necessary circuits.

It should be understood that the base station 4000 shown in fig. 13 is capable of implementing various processes involving the first access network device in the method embodiments shown in fig. 2-10. The operations and/or functions of the respective modules in the base station 4000 are respectively to implement the corresponding flows in the above-described method embodiments. Reference may be made specifically to the description of the above method embodiments, and a detailed description is appropriately omitted herein to avoid redundancy.

BBU 4200 described above may be used to perform actions implemented internally by the first access network device described in the previous method embodiment, while RRU 4100 may be used to perform actions sent to or received from the terminal device by the first access network device described in the previous method embodiment. Please refer to the description of the previous embodiment of the method, which is not repeated herein.

It should be understood that the base station 4000 shown in fig. 13 is only one possible form of access network device, and should not be construed as limiting the present application in any way. The method provided by the application can be applied to access network equipment in other forms. For example, including AAUs, and may also include CUs and/or DUs, or including BBUs and Adaptive Radio Units (ARUs), or BBUs; the network device may also be a Customer Premise Equipment (CPE) or other forms, and the present application is not limited to a specific form of the network device.

Wherein the CU and/or DU may be adapted to perform the actions described in the previous method embodiments as implemented internally by the access network device, and the AAU may be adapted to perform the actions described in the previous method embodiments as sent by the access network device to the terminal device or received from the terminal device. Please refer to the description of the previous embodiment of the method, which is not repeated herein.

The present application further provides a processing apparatus, comprising at least one processor configured to execute a computer program stored in a memory, so as to cause the processing apparatus to perform the method performed by the first access network device in any of the above method embodiments.

An embodiment of the present application further provides a processing apparatus, which includes a processor and a communication interface. The communication interface is coupled with the processor. The communication interface is used for inputting and/or outputting information. The information includes at least one of instructions and data. The processor is configured to execute a computer program to cause the processing device to perform the method performed by the first access network device in any of the above method embodiments.

An embodiment of the present application further provides a processing apparatus, which includes a processor and a memory. The memory is configured to store a computer program, and the processor is configured to call and run the computer program from the memory, so as to cause the processing device to execute the method performed by the first access network device in any of the above method embodiments.

It is to be understood that the processing means described above may be one or more chips. For example, the processing device may be a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a system on chip (SoC), a Central Processing Unit (CPU), a Network Processor (NP), a digital signal processing circuit (DSP), a Microcontroller (MCU), a Programmable Logic Device (PLD), or other integrated chips.

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor. To avoid repetition, it is not described in detail here.

It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip having signal processing capability. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The processor described above may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor.

It will be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), double data rate SDRAM, enhanced SDRAM, SLDRAM, Synchronous Link DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

According to the method provided by the embodiment of the present application, the present application further provides a computer program product, which includes: computer program code which, when run on a computer, causes the computer to perform the method performed by the first access network device in the embodiments shown in fig. 2 to 10.

According to the method provided by the embodiment of the present application, the present application also provides a computer-readable storage medium storing program code, which, when executed on a computer, causes the computer to execute the method performed by the first access network device in the embodiments shown in fig. 2 to 10.

According to the method provided by the embodiment of the present application, the present application further provides a communication system, which includes, but is not limited to, one or more of the foregoing first access network devices and one or more of the foregoing terminal devices. Optionally, the communication system further comprises one or more of the aforementioned second access network devices.

The communication device or the base station in the above respective device embodiments and the first access network device in the method embodiments fully correspond, and the respective steps are performed by respective modules or units, for example, the transceiver unit (transceiver) performs the steps of receiving or transmitting in the method embodiments, and other steps besides transmitting and receiving may be performed by the processing unit (processor). The functions of the specific elements may be referred to in the respective method embodiments. The number of the processors may be one or more.

As used in this specification, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between 2 or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from two components interacting with another component in a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal).

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. a communication method, is characterized in that, comprises:

The first access network device determines that the signal quality of the terminal device in the source cell is lower than a preset threshold, and the source cell is a cell served by the first access network device;

The first access network device, according to the first network slice corresponding to the first session activated by the terminal device in the source cell, and the network slice respectively supported by at least one neighboring cell of the source cell, from the determining a target cell in the at least one neighboring cell, wherein the target cell supports the first network slice;

The first access network device controls the terminal device to switch to the target cell.

2 . The method according to claim 1 , wherein the target cell is another cell except the source cell among the plurality of cells served by the first access network device. 3 .

3. The method of claim 1, wherein the target cell is a cell served by the second access network device.

4. The method of claim 3, wherein the method further comprises:

determining, by the first access network device, a wireless measurement parameter according to the first network slice, network slices supported by the at least one adjacent cell respectively, and wireless resources corresponding to the supported network slices;

The first access network device sends the wireless measurement parameter to the terminal device, where the wireless measurement parameter is used for the terminal device to measure the signal quality of the adjacent cell; The measurement of the signal quality of the neighbor cells is used for the determination of the target cell.

5. The method of claim 3 or 4, wherein the method further comprises:

sending, by the first access network device, a request message to the second access network device, where the request message carries the identification information of the first session and the identification information of the first network slice;

receiving, by the first access network device, radio resource control RRC parameters for handover from the second access network device;

The first access network device sends the RRC parameter to the terminal device.

6. The method according to claim 5, wherein the RRC parameter is related to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device. The radio resource association corresponding to the network slice.

7. A communication method, characterized in that, comprising:

The first access network device determines that the first radio resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session that the terminal device requests to establish or request to activate, and the source cell is the first network slice. The cell served by the access network equipment;

The first access network device determines a target cell, and the second radio resource of the target cell supports the first network slice;

8. The method according to claim 7, wherein the second radio resource further supports a network slice corresponding to a second session of the terminal device, and the second session includes an activated session or a deactivated session .

9. The method of claim 7 or 8, wherein the method further comprises:

The first access network device determines the target frequency range according to the network slice to which the terminal device is allowed to access, the first network slice, and the frequency range corresponding to the first network slice; or

The network slice requested by the first access network device according to the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or registration area where the terminal device is located, and the first network The slice and the frequency range corresponding to the first network slice determine the target frequency range.

10. The method according to claim 9, wherein determining the target cell by the first access network device comprises:

The first access network device determines the target cell from neighboring cells within the site that support the target frequency range, and the neighboring cells within the site are all cells served by the first access network device. other cells than the above-mentioned source cell.

11. The method according to claim 9, wherein determining the target cell by the first access network device comprises:

The first access network device determines the target cell from out-of-station adjacent cells that support the target frequency range, and the out-of-station adjacent cells are adjacent cells of the source cell except for the first cell. A cell other than the cell served by the access network equipment.

12. The method of claim 11, further comprising:

The first access network device determines wireless measurement parameters according to the target frequency range;

The first access network device sends the wireless measurement parameter to the terminal device, where the wireless measurement parameter is used by the terminal device to measure the signal quality of the adjacent cell; the terminal device measures the signal quality of the adjacent cell. Measurements of the signal quality of neighboring cells are used for the determination of the target cell.

13. The method of claim 11 or 12, wherein the method further comprises:

sending, by the first access network device, a request message to a second access network device serving the target cell, where the request message carries the identification information of the first session and the identification information of the first network slice;

The first access network device sends the RRC parameter to the terminal device.

14. The method of claim 13, wherein the RRC parameter is related to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device. The radio resource association corresponding to the network slice.

15. A communication method, comprising:

The first access network device determines that the first radio resource accessed by the terminal device in the source cell does not support the first network slice of the first session that the terminal device requests to establish or request to activate, and the source cell is the first access network slice. The cell served by the network access device;

The first access network device sends a radio resource control RRC connection release message to the terminal device to release the RRC connection with the terminal device.

16. The method of claim 15, further comprising:

The first access network device determines the target frequency range according to the network slice that the terminal device is allowed to access, the first network slice, and the frequency range corresponding to the first network slice; or, the first access network device determines the target frequency range. The network slice requested by the network access device according to the terminal device, the network slice that the terminal device can use according to the subscription, and the network slice supported by the tracking area or registration area where the terminal device is located, the first network slice, and the third network slice. A frequency range corresponding to a network slice, determining the target frequency range; and

The first access network device determines the wireless parameters according to the target frequency range, the network slices supported by the at least one adjacent cell respectively, and the wireless resources corresponding to the supported network slices. cell reselection in the terminal equipment;

The first access network device sends the wireless parameter to the terminal device.

17. A communication device, comprising:

a determining unit, configured to determine that the signal quality of the terminal equipment in the source cell is lower than a preset threshold, and the source cell is the cell served by the device; and is further configured to determine the signal quality of the terminal equipment in the source cell according to the first activation of the terminal equipment in the source cell A first network slice corresponding to a session, and network slices respectively supported by at least one adjacent cell of the source cell, and a target cell is determined from the at least one adjacent cell, wherein the target cell supports the first network slice network slice;

a control unit, configured to control the terminal equipment to switch to the target cell.

18. The apparatus of claim 17, wherein the target cell is another cell other than the source cell among a plurality of cells served by the apparatus.

19. The apparatus of claim 17, wherein the target cell is a cell served by the second access network device.

20. The apparatus according to claim 19, wherein the determining unit is further configured to correspond to the first network slice, the network slices respectively supported by the at least one adjacent cell, and the supported network slices wireless resources, determine wireless measurement parameters;

The apparatus further includes a transceiver unit, configured to send the wireless measurement parameter to the terminal device, where the wireless measurement parameter is used for the terminal device to measure the signal quality of the adjacent cell; wherein, the terminal device The measurement of the signal quality of the neighbor cell by the device is used for the determination of the target cell.

21. The device according to claim 19 or 20, characterized in that, the device further comprises a transceiving unit, and the transceiving unit is configured to:

sending a request message to the second access network device, where the request message carries the identification information of the first session and the identification information of the first network slice;

receiving radio resource control RRC parameters for handover from the second access network device;

Send the RRC parameters to the terminal device.

22. The apparatus of claim 21, wherein the RRC parameter is related to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device. The radio resource association corresponding to the network slice.

23. A communication device, comprising:

a determining unit, configured to determine that the first radio resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session requested by the terminal device to establish or activate, and the source cell is served by the device cell; further used to determine a target cell, the second radio resource of the target cell supports the first network slice;

24. The apparatus of claim 23, wherein the second radio resource further supports a network slice corresponding to a second session of the terminal device, and the second session includes an activated session or a deactivated session .

25. The apparatus according to claim 23 or 24, wherein the determining unit is further configured to correspond to the network slice to which the terminal device is allowed to access, the first network slice, and the first network slice frequency range to determine the target frequency range; or

The determining unit is further configured to: according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, the network slice supported by the tracking area or registration area where the terminal device is located, and the first network slice and the frequency range corresponding to the first network slice to determine the target frequency range.

26 . The apparatus according to claim 25 , wherein the determining unit is specifically configured to determine the target cell from neighboring cells within a site that support the target frequency range, and the neighboring cells within the site are the other cells than the source cell among the plurality of cells served by the device.

27. The apparatus according to claim 25, wherein the determining unit is specifically configured to determine the target cell from an off-site neighboring cell that supports the target frequency range, and the off-site neighboring cell is a A cell other than the cell served by the device among the neighboring cells of the source cell.

28. The apparatus according to claim 27, wherein the determining unit is further configured to determine wireless measurement parameters according to the target frequency range;

The apparatus further includes a transceiver unit, configured to send the wireless measurement parameter to the terminal device, where the wireless measurement parameter is used for the terminal device to measure the signal quality of the adjacent cell; The measurement of the signal quality of the neighbor cells is used for the determination of the target cell.

29. The apparatus according to claim 27 or 28, characterized in that, the apparatus further comprises a transceiving unit, and the transceiving unit is configured to:

sending a request message to the second access network device serving the target cell, where the request message carries the identification information of the first session and the identification information of the first network slice;

Send the RRC parameters to the terminal device.

30. The apparatus of claim 29, wherein the RRC parameter is related to the first network slice, the network slice supported by the second access network device, and the network slice supported by the second access network device. The radio resource association corresponding to the network slice.

31. A communication device, comprising:

a determining unit, configured to determine that the first radio resource accessed by the terminal device in the source cell does not support the first network slice of the first session that the terminal device requests to establish or request to activate, and the source cell is the cell served by the device ;

A transceiver unit, configured to send a radio resource control RRC connection release message to the terminal equipment to release the RRC connection with the terminal equipment.

32. The apparatus according to claim 31, wherein the determining unit is further configured to determine the frequency according to the network slice to which the terminal device is allowed to access, the first network slice, and the frequency corresponding to the first network slice or, the determining unit is further configured to determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, and the network slice supported by the tracking area or registration area where the terminal device is located. The network slice, the first network slice, and the frequency range corresponding to the first network slice, to determine the target frequency range;

The determining unit is further configured to determine the radio parameters according to the target frequency range, the network slices supported by the at least one adjacent cell respectively, and the radio resources corresponding to the supported network slices, and the radio parameters are used for cell reselection of the terminal equipment;

The transceiver unit is further configured to send the wireless parameter to the terminal device.

33. A computer-readable storage medium, characterized by comprising a computer program which, when executed on a computer, causes the computer to perform the method of any one of claims 1 to 16.