CN106162773A - cell reselection method - Google Patents

Abstract

The invention discloses a cell reselection method, which is used for a communication device of a communication system and comprises the steps of receiving device-to-device communication information and first sequencing information broadcast by a network terminal of the communication system; and re-listing a second ranking information based on the device-to-device communication information when the communication device is in an operational condition.

Description

Cell Reselection Method

technical field

The invention relates to a cell reselection method, in particular to a method for adjusting the priority order of the cell reselection procedure corresponding to the supporting situation of device-to-device communication.

Background technique

In a cellular wireless communication system, a communication device communicates with another communication device through a base station, that is, the base station can serve as a relay entity between the communication devices. However, such a communication method is inefficient in terms of coverage area, resource usage, and transmission delay, especially when each communication device is close to each other and capable of communicating with each other. Therefore, the industry proposes Device-to-Device (D2D) communication, that is, two adjacent communication devices can directly communicate with each other (such as sending/receiving packets) without forwarding packets through the base station. Thereby, the coverage area, resource usage and/or transmission delay of the base station are improved.

According to Section 9.1.2 of the 3rd Generation Partnership Project (3GPP) standard TS 36.843, the device-to-device communication can adopt the first mode (mode 1) led by the network side or the second mode led by the client (mode 2) for resource allocation. In the first mode, when two communication devices are within the coverage of the base station and intend to perform device-to-device communication, the base station will allocate required resources to the two communication devices. However, the coverage area of the first mode is limited and cannot be applied to the situation where the communication device is out-of-coverage of the base station. In the second mode, when two communication devices intend to conduct device-to-device communication, they will select specific resources from the resource pool for data transmission. Therefore, the second mode can be applied within the coverage of the communication devices in the base station Outside or in the case of edge-of-coverage, the communication device entering the idle mode mainly uses the second mode.

However, under the existing device-to-device communication structure, the communication device cannot know whether the network supports device-to-device communication, or even whether the network supports the first mode or the second mode of device-to-device communication. Moreover, the value of the CellReselectionPriority parameter in TS 36.331 has nothing to do with whether the network supports device-to-device communication, the first mode or the second mode, so the corresponding cell reselection priority parameter is the highest priority neighboring cell or frequency Device-to-device communication is not necessarily supported. After the communication device performs cell reselection according to the cell reselection priority parameter broadcasted by the network, the communication device may reselect to an adjacent cell that does not support D2D communication, thereby interrupting the existing D2D communication. In this situation, how to improve the way of cell reselection has become the goal of the industry.

Contents of the invention

Therefore, the present invention mainly provides a cell reselection method to adjust the priority order of the cell reselection procedure corresponding to the support situation of the device-to-device communication.

The present invention discloses a cell reselection method, which is used in a communication device of a communication system, including receiving device-to-device (D2D) communication information broadcast by a network end of the communication system and a first ranking information; and when the communication device is in an operation situation, re-listing a second ranking information according to the device-to-device communication information.

The present invention also discloses a cell reselection method, which is used at a network end of a communication system, including broadcasting a device-to-device (D2D) communication information and a first sorting information; wherein, when the In an operation situation of a communication device of the communication system, the communication device relists a second ranking information according to the device-to-device communication information.

Description of drawings

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a device according to Embodiment 1 of the present invention.

FIG. 3 and FIG. 4 are flow charts of the first embodiment of the present invention.

5 and 6 are flowcharts of a process according to another embodiment of the present invention.

Wherein, the reference signs are explained as follows:

10 communication system

UE1, UE2 communication device

ND network side

RAN1, RAN2 communication network

100, 110, 120, 130 base station

100c, 110c, 120c, 130c serving cells

CN core network

20 devices

200 processing units

210 storage units

214 program code

220 communication interface unit

30, 40 process

300～322, 400～422 steps

detailed description

FIG. 1 is a schematic diagram of a communication system 10 according to an embodiment of the present invention. The communication system 10 is a cellular wireless communication system, which can be briefly represented by a network terminal ND and communication devices UE1 and UE2. Wherein, the network end ND can include communication networks RAN1 and RAN2, and the communication networks RAN1 and RAN2 include base stations (base stations) 100, 110, 120, and 130 respectively, and the base stations 100-130 can respectively serve cells 100c, 110c, 120c, 130c, but not limited thereto, a base station can also serve multiple cells depending on the system design. In one embodiment, the communication networks RAN1 and RAN2 may be the Universal Terrestrial Radio Access Network (UTRAN) in the Universal Mobile Telecommunications System (UMTS), and the base stations 100-130 correspond to is a base station (Node-B, NB). In another embodiment, the communication networks RAN1 and RAN2 may be in a Long Term Evolution (LTE) system, an Advanced Long Term Evolution (LTE-Advanced, LTE-A) system or an advanced version of an Advanced Long Term Evolution system An evolved universal terrestrial radio access network (evolved UTRAN, E-UTRAN), and the base stations 100-130 are correspondingly evolved base stations (evolved-NB, eNB). In another embodiment, the communication networks RAN1 and RAN2 may be wireless communication networks conforming to wireless communication standards such as IEEE 802.11 and IEEE 802.16.

Furthermore, the network end ND may also include communication networks RAN1, RAN2 and a core network CN at the same time, wherein the core network CN includes such as Mobility Management Entity (MME), Serving Gateway (Serving Gateway, S-GW) Network entities such as a packet data network (PacketData Network, PDN) channel, a self-organizing network (Self-Organizing Networks, SON) server and/or a radio network controller (Radio Network Controller, RNC). In other words, after the network ND receives information transmitted by a communication device, the information can only be processed by the communication networks RAN1, RAN2, and decisions corresponding to the information are also performed by the communication networks RAN1, RAN2 . On the other hand, the communication networks RAN1 and RAN2 can forward the information to the core network CN, and after the core network CN processes the information, decisions corresponding to the information can be executed by the core network CN. Furthermore, the information can be simultaneously processed by the communication networks RAN1 , RAN2 and the core network CN, and the communication networks RAN1 , RAN2 and the core network CN can coordinate and/or cooperate with each other to carry out decisions related to the information. The communication devices UE1 and UE2 can be a client (User Equipment, UE), a machine type communication (Machine Type Communication, MTC) device, a mobile phone, a notebook computer, a tablet computer, an e-book or a portable computer system . In addition, according to the direction of data transmission, the network end ND and the communication devices UE1 and UE2 can be regarded as the transmitting end or the receiving end respectively. For example, for an uplink (uplink, UL), the communication devices UE1 and UE2 are transmitting The network end ND is the receiving end. For a downlink (DL), the network end ND is the transmitting end and the communication devices UE1 and UE2 are the receiving end.

FIG. 2 is a schematic diagram of a device 20 according to Embodiment 1 of the present invention. The device 20 may be the communication device UE1, UE2 shown in FIG. 1 or a device of the network ND, but is not limited thereto. The device 20 may include a processing device 200 , a storage unit 210 and a communication interface unit 220 . The processing device 200 can be a microprocessor or an application specific integrated circuit (ASIC). The storage unit 210 can be any data storage device for storing a program code 214 , and the processing device 200 can read and execute the program code 214 through the storage unit 210 . For example, the storage unit 210 includes but not limited to Subscriber Identity Module (SIM), Read-Only Memory (ROM), Flash Memory, Random-Access Memory (Random- Access Memory, RAM), CD-ROM/DVD-ROM, Magnetic Tape, Hard Disk and Optical Data Storage Device, etc. The communication interface unit 220 can be a wireless transceiver, which can be used to transmit and receive signals (such as information or packets, etc.) according to the processing results of the processing device 200 .

3 and 4 are flowcharts of a process 30 according to Embodiment 1 of the present invention. The process 30 can be used in the communication device UE1 in FIG. 1 to perform cell reselection. The process 30 can be compiled into a program code 214, which includes the following steps:

Step 300: start.

Step 302: The communication device UE1 receives a device-to-device (D2D) communication information and a first sorting information broadcast by the network ND. Wherein, the D2D communication information is related to whether a plurality of neighboring cells or a plurality of frequencies of the network ND support a D2D communication.

Step 304: When the communication device UE1 is in an operation situation, the communication device UE1 relists a second ranking information according to the device-to-device communication information. Among the plurality of neighboring cells or frequencies, neighboring cells or frequencies supporting D2D communication are ranked before neighboring cells or frequencies not supporting D2D communication.

Step 306: According to the second ranking information, select at least one candidate neighboring cell or at least one candidate frequency cell corresponding to the frequency that is ranked higher among multiple neighboring cells or multiple frequencies, and determine at least one candidate neighboring cell or at least one candidate frequency cell A ranking relationship between candidate frequency cells and the serving cell 100c.

Step 308: Execute a first cell reselection criterion when it is determined that the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is the same as that of the serving cell 100c according to the second ranking information.

Step 310: Perform an R criterion sorting according to a first calculation result of the serving cell and at least a second calculation result of at least one candidate neighboring cell or at least one candidate frequency cell.

Step 312: sorting according to the R criterion, the communication device UE1 selects at least one candidate neighboring cell or at least one candidate frequency cell with the highest priority.

Step 314: Execute a second cell reselection criterion when the ranking of the at least one candidate neighbor cell or the at least one candidate frequency cell is different from the ranking of the serving cell 100c according to the second ranking information.

Step 316: When the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is prior to the ranking of the serving cell 100c, and when at least one first measurement result of at least one candidate neighboring cell or at least one candidate frequency cell is within a time When the interval Treselection _RAT is greater than a first reference value, the communication device UE1 selectively selects a cell from at least one candidate neighboring cell or at least one candidate frequency cell according to at least one second calculation result.

Step 318: When the ranking of at least one candidate neighbor cell or at least one candidate frequency cell is behind the ranking of the serving cell 100c, and when a second measurement result of the serving cell 100c is less than a first measurement result in the time interval Treselection _RAT When two reference values are used, and when the first measurement results of at least one candidate neighboring cell or at least one candidate frequency cell are greater than a third reference value in the time interval Treselection _RAT , the communication device UE1 selectively bases on at least one second calculation As a result, a cell is selected among at least one candidate neighbor cell or at least one candidate frequency cell.

Step 320: Perform cell reselection to the selected cell.

Step 322: end.

Specifically, according to step 302, the communication device UE1 resides in a serving cell (such as the cell 100c) and can receive a system information broadcast by the serving cell 100c, and the cells 110c-130c are neighboring cells of the serving cell 100c. Wherein, the system information includes a device-to-device communication information and a first sorting information, which can be passed through a third-type system information block (System Information Block Type 3, SIB3), a fifth-type system information block (SIB5), the first SIB6, SIB7, SIB8, or a radio resource control (RRC) connection release. The first sorting information is used to indicate the priority order of multiple adjacent cells or multiple frequencies of the network ND in the cell reselection procedure, which includes multiple first cell reselection priority (CellReselectionPriority) parameters. Each first cell reselection priority parameter is an integer value between 0 and 7 according to the 3rd Generation Partnership Project (3GPP) standard TS 36.331, wherein 7 corresponds to the highest priority. Among them, multiple adjacent cells refer to cells with the same frequency as serving cell 100c (such as cell 110c), multiple frequencies refer to frequencies different from serving cell 100c (such as the frequency corresponding to cell 120c) or cross-system radio access technology (inter Radio Access Technology, inter-RAT) frequency (such as the frequency corresponding to the cell 130c). In addition, the D2D communication information is related to whether a plurality of neighboring cells (such as the cell 110c ) or multiple frequencies (such as the frequencies corresponding to the cells 120c and 130c ) of the network ND support a D2D communication. For example, Table 1 lists the possible contents of the system information, which may include Absolute Radio Frequency Channel Number (ARFCN) and information about whether to support D2D communication (ie, D2D communication information). Wherein, an absolute wireless channel number corresponds to a specific uplink frequency and a specific downlink frequency, and corresponds to the absolute wireless channel number of the serving cell 100c, and the system information also includes a cell identification code (Cell ID), for example, The cell identification code of the neighboring cell 110c having the same frequency as the serving cell 100c may be one of 1 to 4.

Table I

In other words, since the communication device UE1 can receive the D2D communication information broadcast by the network terminal ND, the communication device UE1 can know the support situation of multiple adjacent cells or multiple frequencies for the D2D communication.

Afterwards, according to step 304, when the communication device UE1 is in an operation situation, the communication device UE1 adjusts the received first ranking information to the second ranking information according to the device-to-device communication information. Wherein, the operation situation is that the communication device UE1 performs a device-to-device communication procedure in idle mode; or, the operation situation is that the communication device UE1 intends to perform a device-to-device communication procedure in the idle mode; or, the operation situation is that the communication device UE1 intends to perform a device-to-device communication procedure and sends a device-to-device communication indication (ProSe interest indication) to the network ND, but the network ND does not respond, and the communication device UE1 leaves a connected mode. Moreover, the second ranking information also includes multiple second cell reselection priority parameters, and the highest priority rank corresponds to the largest value. In the second ranking information, the neighboring cells or frequencies that support D2D communication among the plurality of neighboring cells or frequencies are ranked before the neighboring cells or frequencies that do not support D2D communication, that is, the neighboring cells that support D2D communication The cell or frequency has the larger second cell reselection priority parameter. For example, please refer to Table 1 and Table 2, wherein Table 1 and Table 2 respectively list the absolute wireless channel numbers corresponding to the first cell reselection priority parameter and the second cell reselection priority parameter before and after reordering according to step 304 situation. As shown in Table 1, before reordering in step 304, the first cell reselection priority parameters correspond to different absolute wireless channel numbers and are different integer values, and as shown in Table 2, after reordering in step 304, the second The cell reselection priority parameter adjusts the value of the first cell reselection priority parameter corresponding to different absolute wireless channel numbers and information about whether D2D communication is supported. For example, although the frequency corresponding to the absolute wireless channel number 1650 has a higher priority first cell reselection priority parameter (integer value 6), but because it does not support device-to-device communication, its second cell reselection priority parameter is sorted backward to integer value 3. In addition, although the cells with cell IDs 1 to 4 have the same absolute wireless channel number 1600, they have different secondary cell reselection priority parameters because of the different situations supporting D2D communication, that is, even adjacent cells 110c has the same frequency as the serving cell 100c, but their priorities in the cell reselection procedure may be different.

Table II

In other words, since the communication device UE1 will re-list the second sorting information according to the D2D communication information, so that the neighboring cells or frequencies that support D2D communication among the multiple neighboring cells or multiple frequencies are sorted before the non-supporting devices. The adjacent cells or frequencies for device-to-device communication are prior to each other, so the communication device UE1 can perform cell reselection according to the supporting conditions of multiple adjacent cells or multiple frequencies for device-to-device communication, and relatively preferentially select adjacent cells that support device-to-device communication or frequency.

Next, in step 306, according to the second ranking information, at least one candidate neighboring cell (such as cell 110c) or at least one candidate frequency cell ( such as the cell 120c or 130c), and determine the ranking relationship between at least one candidate neighboring cell or at least one candidate frequency cell and the serving cell 100c. Wherein, according to FIG. 3 , the cells whose cell identification codes are 2 and 3 are selected first in step 306 .

In step 308, when it is judged according to the second ranking information that the ranking of at least one candidate neighboring cell (such as a cell whose cell identification code is 2, 3) or at least one candidate frequency cell is the same as the ranking of the serving cell 100c, a first A cell reselection criterion. The first cell reselection criterion is similar to Section 5.2.4.6 of the 3rd Generation Partnership Project standard TS 36.304, which includes steps 310 and 312 . In step 310, an R criterion is performed according to the value of the serving cell ranking criterion (cell-ranking criterion Rs) of the serving cell 100c and the value of the neighboring cell ranking criterion (cell-ranking criterion Rn) of at least one candidate neighboring cell or at least one candidate frequency cell sorting, and, in step 312, sorting according to the R criterion, the communication device UE1 selects a cell with the highest ranking among at least one candidate neighboring cell or at least one candidate frequency cell, and performs cell reselection. Wherein, the R criterion sorting refers to sorting the standard values of the serving cell and the neighboring cells, that is, the measured value of at least one candidate neighboring cell or at least one candidate frequency cell must be offset from the value of the serving cell 100c Measured value comparison.

In step 314, when it is determined according to the second ranking information that the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is different from the ranking of the serving cell 100c, a second cell reselection criterion is executed. The second cell reselection criterion may be similar to the content in section 5.2.4.5 of the 3rd Generation Partnership Project standard TS36.304, which includes steps 316 and 318 . In step 316, when the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is prior to the ranking of the serving cell 100c, and when the first measurement result of at least one candidate neighboring cell or at least one candidate frequency cell is within a time When the interval Treselection _RAT is greater than the first reference value, the communication device UE1 selects at least one candidate neighboring cell or at least one candidate frequency cell with the highest priority in the sorting result corresponding to the communication system type and selectively according to the sorting standard value of the neighboring cells. cell, and perform cell reselection. In step 318, when the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is behind the ranking of the serving cell 100c, and when the second measurement results of the serving cell 100c are less than the second reference in the time interval Treselection _RAT value, and when the first measurement result of at least one candidate neighboring cell or at least one candidate frequency cell is greater than the third reference value in a time interval Treselection _RAT , the corresponding communication system type is selected according to the neighboring cell sorting standard value The communication device UE1 selects at least one candidate neighbor cell or at least one candidate frequency cell with the highest priority among the ranking results, and performs cell reselection. Wherein, according to the communication system type, the first measurement result and the second measurement result may be a cell selection quality (Squal) value indicating received signal quality or a cell selection receive level indicating received signal strength (Cell selection receive level, Srxlev) value, the first reference value can correspond to Thresh _{X, HighQ} value or Thresh _{X, HighP} value, the second reference value corresponds to Thresh _{Serving, LowQ} value, and the third reference value can correspond to Thresh _{X, LowQ} value or Thresh _{X, LowP} value. In addition, when there is only one candidate neighboring cell or one candidate frequency cell, or when the first measurement results of only one cell in at least one candidate neighboring cell or at least one candidate frequency cell are greater than the first reference value in the time interval Treselection _RAT or the third reference value, the communication device UE1 directly selects this cell for cell reselection without performing sorting corresponding to the neighboring cell sorting standard value.

In other words, after the communication device UE1 re-lists the second ranking information according to the D2D communication information, the ranking of the second ranking information may be different even though the frequency of the adjacent cell is the same as that of the serving cell 100c. In this case, only the first cell reselection criterion in step 308 or the second cell reselection criterion in step 314 needs to be performed according to whether the ordering is the same, and it is not necessary to consider whether the frequency is the same as that of the serving cell 100c.

The communication system 10 in FIG. 1 , the device 20 in FIG. 2 , or the process 30 in FIG. 3 are embodiments of the present invention, and those skilled in the art may make various modifications accordingly, and are not limited thereto. For example, in order to further improve the efficiency of cell reselection, please refer to FIG. 5 and FIG. 6 . FIG. 5 and FIG. 6 are flowcharts of a process 40 according to another embodiment of the present invention. The process 40 can be used in the communication device UE1 in FIG. 1 to perform cell reselection. The process 40 can be compiled into a program code 214, which includes the following steps:

Step 400: start.

Step 402: The communication device UE1 receives a device-to-device communication message and a first ranking message broadcast by the network terminal ND. Wherein, the D2D communication information is related to whether the multiple adjacent cells or multiple frequencies of the network ND support the first mode (mode 1) or the second mode (mode 2) of the D2D communication.

Step 404: When the communication device UE1 is in an operation situation, the communication device UE1 re-lists a second ranking information according to the device-to-device communication information, wherein, according to supporting the first mode and the second mode, only supporting the second mode, Only the first mode is supported, and the D2D communication is not supported and reordered.

Step 406: According to the second ranking information, select at least one candidate neighboring cell or at least one candidate frequency cell corresponding to the frequency that is ranked higher among multiple neighboring cells or multiple frequencies, and determine at least one candidate neighboring cell or at least one candidate frequency cell A ranking relationship between candidate frequency cells and the serving cell 100c.

Step 408: Execute a first cell reselection criterion when it is determined that the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is the same as that of the serving cell 100c according to the second ranking information.

Step 410: Perform an R criterion sorting according to a first calculation result of the serving cell and at least a second calculation result of at least one candidate neighboring cell or at least one candidate frequency cell.

Step 412: sorting according to the R criterion, the communication device UE1 selects at least one candidate neighboring cell or at least one candidate frequency cell with the highest priority.

Step 414: Execute a second cell reselection criterion when the ranking of the at least one candidate neighbor cell or the at least one candidate frequency cell is different from the ranking of the serving cell 100c according to the second ranking information.

Step 416: When the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is prior to the ranking of the serving cell 100c, and when at least one first measurement result of at least one candidate neighboring cell or at least one candidate frequency cell is within a time When the interval Treselection _RAT is greater than a first reference value, the communication device UE1 selectively selects a cell from at least one candidate neighboring cell or at least one candidate frequency cell according to at least one second calculation result.

Step 418: When the ranking of at least one candidate neighboring cell or at least one candidate frequency cell is behind the ranking of the serving cell 100c, and when a second measurement result of the serving cell 100c is less than a first measurement result in the time interval Treselection _RAT When two reference values are used, and when the first measurement results of at least one candidate neighboring cell or at least one candidate frequency cell are greater than a third reference value in the time interval Treselection _RAT , the communication device UE1 selectively bases on at least one second calculation As a result, a cell is selected among at least one candidate neighbor cell or at least one candidate frequency cell.

Step 420: Perform cell reselection to the selected cell.

Step 422: end.

It can be seen from the above that the structure of the process 40 is roughly similar to that of the process 30. The difference between the two is that, according to step 402, the communication device UE1 residing in the serving cell 100c receives the first ranking information broadcast by the serving cell 100c and the device-to-device Communication information, wherein the device-to-device communication information is further related to whether multiple adjacent cells (such as the cell 110c) or multiple frequencies (such as the frequencies corresponding to the cells 120c and 130c) of the network ND support the first mode of device-to-device communication or second mode. In this way, the communication device UE1 can know the support situation of multiple neighboring cells or multiple frequencies for D2D communication.

Furthermore, according to step 404, when the communication device UE1 is in operation, the communication device UE1 adjusts the received first ranking information to the second ranking information according to the device-to-device communication information. Since the communication device entering the idle mode mainly uses the second mode, in one embodiment, the neighboring cells or frequencies that support the first mode and the second mode among multiple neighboring cells or multiple frequencies are sorted to only support the first mode Prior to the adjacent cells or frequencies of multiple adjacent cells or multiple frequencies, the adjacent cells or frequencies that only support the second mode are sorted before the adjacent cells or frequencies that only support the first mode, and among the multiple adjacent cells or multiple frequencies Neighboring cells or frequencies that only support the first mode are ordered before neighboring cells or frequencies that do not support D2D communication. For example, please refer to Table 3 and Table 4, wherein Table 3 and Table 4 respectively list the absolute wireless channel numbers corresponding to the first cell reselection priority parameters and the second cell reselection priority parameters before and after the reordering according to step 404 situation. As shown in Table 3 and Table 4, corresponding to different absolute wireless channel numbers and supporting device-to-device communication, the first ranking information is rearranged into the second ranking information. For example, although the first cell reselection priority parameter (Table 3) of the frequency corresponding to the absolute wireless channel number 1650 is relatively prioritized (integer value 6), since it does not support device-to-device communication, its second cell reselection priority parameter ( Table 4) Sort backwards to integer value 2. And, according to the second sorting information (that is, the second cell reselection priority parameter is a larger integer value of 5), in step 406 only the cell whose cell identification code is 2 will be selected first, and then proceed to steps 408～ 412.

Table three

Table four

However, the present invention is not limited thereto. In another embodiment, the adjacent cells or frequencies supporting the first mode and the second mode among the multiple adjacent cells or frequencies are sorted before the adjacent cells or frequencies that only support the second mode, and the multiple adjacent cells or multiple Neighboring cells or frequencies that only support the second mode in frequencies are sorted before neighboring cells or frequencies that only support the first mode, and multiple neighboring cells or frequencies that only support the first mode are sorted before unsupported Neighboring cells or frequencies for device-to-device communications. For example, please refer to Table 3 and Table 5, wherein Table 3 and Table 5 respectively list the absolute wireless channel numbers corresponding to the first cell reselection priority parameter and the second cell reselection priority parameter before and after reordering according to step 404 situation. As shown in Table 3 and Table 5, corresponding to different absolute wireless channel numbers and supporting device-to-device communication, the first ranking information is rearranged into the second ranking information. For example, although the first cell reselection priority parameter (Table 3) of the frequency corresponding to the absolute wireless channel number 1650 is relatively prioritized (integer value 6), since it does not support device-to-device communication, its second cell reselection priority parameter ( Table V) Sort backwards to integer value 3. And, according to the second sorting information, in step 406, only the cell whose cell identification code is 2 will be selected first (that is, the second cell reselection priority parameter is a larger integer value of 7), and then proceed to step 414, 416.

Table five

In other words, since the communication device UE1 will re-list the second ranking information according to supporting the first mode and the second mode, only supporting the second mode, only supporting the first mode, and not supporting device-to-device communication, the communication The device UE1 may perform cell reselection according to the supporting conditions of multiple neighboring cells or multiple frequencies for D2D communication, and relatively preferentially select neighboring cells or frequencies that support D2D communication.

It should be noted that the method of rearranging the first-ranked information into the second-ranked information is not limited to the reordering steps 504, 704, and 804 in Figures 5, 7, and 8, and can be appropriately adjusted according to different system requirements and design considerations . For example, in the reordering steps 504, 704, 804, the first cell reselection priority parameter of the serving cell 100c is the same as the second cell reselection priority parameter, but in another embodiment, the second The maximum value of the cell reselection priority parameter is adjusted to an integer value of 5, and the reselection priority parameters of the serving cell 100c, other neighboring cells, or second cell of other frequencies are arranged in sequence. In addition, in another embodiment, the second cell reselection priority parameters of neighboring cells or frequencies that do not support D2D communication can be set to zero.

It can be seen from the above that the spirit of the present invention is a cell reselection method for the communication device UE1, wherein the communication device UE1 receives the device-to-device communication information and the first sorting information broadcast by the network terminal ND, and when the communication device UE1 is operating In this case, the second ranking information is re-listed according to the D2D communication information. Similarly, the cell reselection method of the present invention can also be applied to the network ND, wherein the network ND broadcasts the device-to-device communication information and the first ranking information, and when the communication device UE1 is in operation, the communication device UE1 receives The received device-to-device communication information relists the second ranking information. In addition, the method for reordering the second sorting information is related to the content of the D2D communication information. That is to say, when the device-to-device communication information is related to whether the plurality of neighboring cells or the plurality of frequencies support the device-to-device communication (step 302), the plurality of neighboring cells or the plurality of frequencies supporting the neighboring cells of the device-to-device communication or The frequencies are ranked in the second ranking information before neighboring cells or frequencies that do not support D2D communication (step 304). And, when the device-to-device communication information is related to whether the plurality of neighboring cells or the plurality of frequencies support the first mode or the second mode of the device-to-device communication (step 402), according to the plurality of neighboring cells or the plurality of frequencies supporting the first mode mode and the second mode, only the second mode is supported, only the first mode is supported, and D2D communication is not supported, the communication device UE1 reorders the first ranking information into the second ranking information (step 404 ).

In the prior art, the communication device cannot know whether the network supports the device-to-device communication, or even whether the network supports the first mode or the second mode of the device-to-device communication. Moreover, the value of the first cell reselection priority parameter in TS 36.331 has nothing to do with whether the network supports device-to-device communication, the first mode or the second mode, so the corresponding first cell reselection priority parameter is the highest priority neighboring cell or Frequency does not necessarily support device-to-device communication.

In contrast, the network terminal ND of the present invention will broadcast whether it supports D2D communication, or even whether it supports the first mode or the second mode of D2D communication, so the communication device UE1 can know the adjacent cell or the frequency pair D2D The support status of device communication. Moreover, according to the supporting situation of D2D communication, the communication device UE1 will adjust the first sorting information including the first cell reselection priority parameter to the second sorting information, so that the adjacent cells or frequencies that support D2D communication are more important. Priority sorting can improve the efficiency of cell reselection. Correspondingly, the communication device UE1 executes the first cell reselection criterion or the second cell reselection criterion according to whether the rankings are the same, so as to select a cell for cell reselection.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (18)

1. A cell reselection method, used in a communication device of a communication system, characterized in that, the cell reselection method includes: receiving a device-to-device communication message and a first sorting message broadcast by a network terminal of the communication system; and When the communication device is in an operation situation, a second ranking information is relisted according to the device-to-device communication information. 2. The cell reselection method according to claim 1, wherein the D2D communication information is related to whether a plurality of neighboring cells or a plurality of frequencies of the network support a D2D communication. 3. The cell reselection method according to claim 2, wherein the relisting of the second ranking information according to the device-to-device communication information includes: The plurality of neighboring cells or frequencies that support the device-to-device communication are ordered before neighboring cells or frequencies that do not support the device-to-device communication. 4. The cell reselection method according to claim 1, wherein the device-to-device communication information is related to whether the plurality of neighboring cells or the plurality of frequencies of the network support the device-to-device communication A first mode or a second mode. 5. The cell reselection method according to claim 4, wherein the relisting of the second ranking information according to the device-to-device communication information includes: sorting neighboring cells or frequencies among the plurality of neighboring cells or frequencies supporting the first mode and the second mode before neighboring cells or frequencies supporting only the first mode; sorting neighboring cells or frequencies supporting only the second mode in the plurality of neighboring cells or frequencies prior to neighboring cells or frequencies supporting only the first mode; and Ranking neighboring cells or frequencies that only support the first mode among the plurality of neighboring cells or frequencies that do not support the device-to-device communication. 6. The cell reselection method according to claim 5, wherein re-listing the second sorting information according to the device-to-device communication information further comprises listing the plurality of neighboring cells or the Neighboring cells or frequencies supporting the first mode and the second mode among the plurality of frequencies are ordered before neighboring cells or frequencies supporting only the second mode. 7. The cell reselection method according to claim 1, wherein the operation situation is that the communication device performs a device-to-device communication procedure in an idle mode, or the communication device intends to A device-to-device communication procedure is performed, or the communication device sends a device-to-device communication instruction to the network, but the network does not respond, so that the communication device leaves a connection mode. 8. The cell reselection method according to claim 1, wherein the cell reselection method further comprises: selecting at least one candidate ranked as the highest priority among the plurality of neighboring cells or the plurality of frequencies according to the second ranking information; When it is determined according to the second ranking information that the ranking of the at least one candidate is the same as that of a serving cell, a first cell reselection criterion is executed, wherein the first cell reselection criterion includes: performing an R criterion sorting according to a first calculation result of the serving cell and at least a second calculation result of the at least one candidate; and sorting according to the R criterion, the communication device performs cell reselection to a candidate with the highest ranking among the at least one candidate; and When it is judged that the ranking of the at least one candidate is different from the ranking in the serving cell according to the second ranking information, a second cell reselection criterion is executed, wherein the second cell reselection criterion includes: When the ranking of the at least one candidate is prior to the ranking of the serving cell, and when the at least one first measurement result of the at least one candidate is greater than a first reference value in a time interval, the communication The device selectively performs cell reselection to one of the at least one candidate according to the at least one second calculation result; and When the ranking of the at least one candidate is behind the ranking of the serving cell, and when a second measurement result of the serving cell is less than a second reference value in the time interval, and when the When at least one candidate first measurement result is greater than a third reference value in the time interval, the communication device selectively performs cell reselection to the at least one second calculation result based on the at least one second calculation result. one of the candidates; Wherein, the communication device resides in the serving cell. 9. The cell reselection method according to claim 8, wherein the time interval is Treselection _RAT defined by the 3rd Generation Partnership Project standard, and the first measurement result and the second measurement result is the cell reselection quality value or cell re-reception level value defined by the 3rd Generation Partnership Project standard, and the first reference value is the Thresh _{X, HighQ} value or Thresh _{X, HighP} value defined by the 3rd Generation Partnership Project standard , the second benchmark value is the Thresh _{Serving, LowQ} value defined by the 3rd Generation Partnership Project standard, and the third benchmark value is the Thresh _{X, LowQ} value or Thresh _{X, LowP} value defined by the 3rd Generation Partnership Project standard , the first calculation result is the serving cell sorting standard value defined by the Third Generation Partnership Project standard, and the second calculation result is the neighboring cell sorting standard value defined by the Third Generation Partnership Project standard. 10. A cell reselection method used at a network end of a communication system, characterized in that the cell reselection method includes: broadcasting a device-to-device communication message and a first ranking message; Wherein, when a communication device of the communication system is in an operation situation, the communication device relists a second ranking information according to the device-to-device communication information. 11. The cell reselection method according to claim 10, wherein the D2D communication information is related to whether a plurality of adjacent cells or a plurality of frequencies of the network support a D2D communication. 12. The cell reselection method according to claim 11, wherein relisting the second ranking information according to the device-to-device communication information includes: The plurality of neighboring cells or frequencies that support the device-to-device communication are ordered before neighboring cells or frequencies that do not support the device-to-device communication. 13. The cell reselection method according to claim 10, wherein the device-to-device communication information is related to whether the plurality of neighboring cells or the plurality of frequencies of the network support the device-to-device communication A first mode or a second mode. 14. The cell reselection method according to claim 13, wherein relisting the second ranking information according to the device-to-device communication information includes: sorting neighboring cells or frequencies of the plurality of neighboring cells or frequencies supporting the first mode and the second mode before neighboring cells or frequencies supporting only the first mode; sorting neighboring cells or frequencies supporting only the second mode in the plurality of neighboring cells or frequencies prior to neighboring cells or frequencies supporting only the first mode; and Ranking neighboring cells or frequencies among the plurality of neighboring cells or frequencies that only support the first mode before neighboring cells or frequencies that do not support the device-to-device communication. 15. The cell reselection method according to claim 14, wherein re-listing the second sorting information according to the device-to-device communication information further comprises re-listing the plurality of neighboring cells or the Neighboring cells or frequencies supporting the first mode and the second mode among the plurality of frequencies are ordered before neighboring cells or frequencies supporting only the second mode. 16. The cell reselection method according to claim 10, wherein the operation situation is that the communication device performs a device-to-device communication procedure in an idle mode, or the communication device intends to A device-to-device communication procedure is performed, or the communication device sends a device-to-device communication instruction to the network, but the network does not respond, so that the communication device leaves a connection mode. 17. The cell reselection method according to claim 10, wherein the cell reselection method further comprises: selecting at least one candidate ranked as the highest priority among the plurality of neighboring cells or the plurality of frequencies according to the second ranking information; When it is determined according to the second ranking information that the ranking of the at least one candidate is the same as that of a serving cell, a first cell reselection criterion is executed, wherein the first cell reselection criterion includes: performing an R criterion sorting according to a first calculation result of the serving cell and at least a second calculation result of the at least one candidate; and sorting according to the R criterion, the communication device performs cell reselection to a candidate with the highest ranking among the at least one candidate; and When it is judged that the ranking of the at least one candidate is different from the ranking in the serving cell according to the second ranking information, a second cell reselection criterion is executed, wherein the second cell reselection criterion includes: When the ranking of the at least one candidate is prior to the ranking of the serving cell, and when the at least one first measurement result of the at least one candidate is greater than a first reference value in a time interval, the communication The device selectively performs cell reselection to one of the at least one candidate according to the at least one second calculation result; and When the ranking of the at least one candidate is behind the ranking of the serving cell, and when a second measurement result of the serving cell is less than a second reference value in the time interval, and when the When at least one candidate first measurement result is greater than a third reference value in the time interval, the communication device selectively performs cell reselection to the at least one second calculation result based on the at least one second calculation result. one of the candidates; Wherein, the communication device resides in the serving cell. 18. The cell reselection method according to claim 17, wherein the time interval is Treselection _RAT defined by the Third Generation Partnership Project standard, and the first measurement result and the second measurement result is the cell reselection quality value or cell re-reception level value defined by the 3rd Generation Partnership Project standard, and the first reference value is the Thresh _{X, HighQ} value or Thresh _{X, HighP} value defined by the 3rd Generation Partnership Project standard , the second benchmark value is the Thresh _{Serving, LowQ} value defined by the 3rd Generation Partnership Project standard, and the third benchmark value is the Thresh _{X, LowQ} value or Thresh _{X, LowP} value defined by the 3rd Generation Partnership Project standard , the first calculation result is the serving cell sorting standard value defined by the Third Generation Partnership Project standard, and the second calculation result is the neighboring cell sorting standard value defined by the Third Generation Partnership Project standard.