JP7739346B2 - Terminal device, base station device, control method, and program for advanced traffic flow control - Google Patents

Description

The present invention relates to technology for controlling network access and traffic flow.

Cellular communication standards such as the 5th generation (5G) standard of the Third Generation Partnership Project (3GPP (registered trademark)) stipulate that access classes and access categories be assigned to terminal devices for the purpose of restricting and controlling communications. Based on these specifications, base station devices broadcast notification signals containing information restricting the transmission of connection request signals by terminal devices of specific access classes and access categories. This information includes information such as the restriction rate for each access class. Upon receiving this information, terminal devices determine whether or not to transmit connection request signals based on the value indicating their assigned access class and the received information. Terminal devices then do not transmit connection request signals unless they determine that transmission is permitted. This reduces the signal processing load on core network devices, Internet Protocol (IP) Multimedia Subsystem (IMS), and other systems.

When access restrictions are based on access classes or access categories, there may be many terminal devices that are not affected by such access restrictions. In such cases, access to the network and traffic flow may not be restricted appropriately, and the load on core network devices, IMS, etc. may not be sufficiently reduced.

The present invention provides technology for advanced control of network access or traffic flow.

A terminal device according to one aspect of the present invention is a terminal device of a cellular communication system, and has an identification means for identifying a port number corresponding to a type of application or communication protocol to be executed through communication with a base station device of the cellular communication system, and a transmission means for transmitting to the base station device a radio signal including an information element that stores the port number and is used by the base station device to control access to a network .

A base station device according to one aspect of the present invention is a base station device of a cellular communication system, and has: a receiving means for receiving a radio signal from a terminal device of the cellular communication system , the radio signal including an information element storing a port number corresponding to the type of application or communication protocol that the terminal device executes through communication with the base station device; an identifying means for identifying the type of application or the communication protocol based on the port number; and a control means for controlling access to a network based on the result of identifying the type of application or the communication protocol.

The present invention enables advanced control of network access or traffic flow.

FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. FIG. 1 is a diagram illustrating an example of data transfer in conventional communication. FIG. 2 illustrates an example of a hardware configuration of the apparatus. FIG. 2 is a diagram illustrating an example of a functional configuration of a base station device. FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal device. FIG. 2 is a diagram illustrating an example of the functional configuration of a core network device. FIG. 1 is a diagram illustrating an example of a flow of processing executed in a wireless communication system. FIG. 1 is a diagram illustrating an example of a flow of processing executed in a wireless communication system.

The following embodiments are described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the multiple features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numbers are used for identical or similar components, and duplicate descriptions will be omitted.

(Configuration of wireless communication system)
FIG. 1 shows an example of the configuration of a wireless communication system according to this embodiment. This wireless communication system is a cellular wireless communication system conforming to a cellular communication standard such as the fifth generation (5G) standard of the Third Generation Partnership Project (3GPP (registered trademark)). This wireless communication system includes, for example, a base station device 101 and a terminal device 102. Upon receiving a connection request signal from the terminal device 102, the base station device 101 is configured to establish a connection with the terminal device 102 and provide wireless communication services. The base station device 101 is further connected to network devices such as a core network device 103. Note that the core network device 103 is merely illustrated schematically, and core network functions are implemented by one or more network nodes. The core network device 103 may be connected to an application server (not shown) for executing applications such as the Internet Protocol (IP) Multimedia Subsystem (IMS). Hereinafter, devices downstream of the base station device 101, such as the core network device 103, as viewed from the terminal device 102 may be referred to as "subsequent devices." Also, in order to simplify the explanation, FIG. 1 shows only one base station device 101 and two terminal devices 102, but it goes without saying that a large number of base station devices and a large number of terminal devices may exist.

In the wireless communication system according to this embodiment, a priority is set for the terminal device 102 based on the access class and access category. The base station device 101 then broadcasts a notification signal containing information such as restriction rate information to restrict access based on the access class and access category. When the terminal device 102 receives this information, it references the restriction rate corresponding to the access class and access category assigned to it and determines whether it is permitted to transmit a connection request signal. If the terminal device 102 determines that it is permitted to transmit a connection request signal, it transmits the connection request signal. On the other hand, if it determines that it should not transmit a connection request signal, it does not transmit the connection request signal, and thereafter does not transmit a connection request signal for a certain period of time.

Even when access restrictions based on such access classes and access categories are used, there may be terminal devices that transmit connection request signals without being affected by these restrictions. For example, it is conceivable that a terminal device attempting to transmit data with malicious intent may ignore such restrictions and attempt to transmit a connection request signal. Because such access restrictions restrict the transmission of connection request signals on the terminal device side, when the base station device 101 receives such a connection request signal, it may forward the signal to the core network device 103 or the like without restricting the signal flow rate. Therefore, if there are a large number of such terminal devices, the load on the core network device 103 or the like will increase excessively.

If the base station device 101 could recognize communication protocols at the application layer and block communications using specific communication protocols, it would be possible to mitigate this increased load. However, the base station device 101 may not be able to recognize application layer communication protocols and may simply forward the received signal to other devices as a data call. For example, if a Session Initiation Protocol (SIP) signal, which controls voice calls, is sent from the terminal device 102 to the base station device 101, the signal is treated as a data call by the base station device 101 and the subsequent core network device 103 because SIP call processing is performed at the application layer. As a result, as shown in Figure 2, the base station device 101 and the core network device 103 transparently forward the signal as is. Similarly, traffic from a distributed denial of service (DDOS) attack against the terminal device 102 is also treated as a data call by the base station device 101 and the like, and the base station device 101 transparently forwards the traffic. Furthermore, for example, automatic distribution of operating system (OS) updates from a server to terminal device 102 is treated as a simple data call by base station device 101, and base station device 101 simply forwards the signal to other devices.

As such, conventionally, base station devices 101 do not have a mechanism for controlling the flow rate of certain data communications, resulting in situations where the effectiveness of access control is limited. In consideration of these circumstances, this embodiment provides a procedure for enabling the base station device 101 to identify the application layer communication protocol when it receives a predetermined control signal, such as a connection request signal. More specifically, the terminal device 102 transmits a predetermined signal, such as a connection request signal, including an information element (IE) for identifying the communication protocol to the base station device 101. This information element may include, for example, information indicating a transport layer port number. In other words, transport layer port numbers corresponding to each application layer communication protocol are predetermined, and these port numbers are specified in the information element. Note that the connection request signal is an example of a signal whose contents can be recognized (decoded) by the base station device 101, and other signals may also be used. Note that this information element may be, for example, a medium access control (MAC) layer information element. However, this is not limited to this. For example, this information element may be any information element of a communication layer that the base station device 101 can analyze, such as the physical (PHY) layer, radio link control (RLC) layer, or packet data convergence protocol (PDCP) layer. This allows the base station device 101 to identify the communication protocol used for communication of the signal transmitted by the terminal device 102, and enables control of the data flow rate according to the communication protocol.

For example, when the base station device 101 receives a signal with port number 5060 set, it can identify the signal as a SIP signal. Then, when it is necessary to block a voice call, for example, the base station device 101 can block the signal without forwarding it to the core network device 103. Note that SIP is just one example. For other communication protocols, a unique port number that can identify the communication protocol is provided, and the port number is specified in an IE within the signal, allowing the base station device 101 to identify the communication protocol through the signal and perform traffic flow control for each communication protocol. Furthermore, a port number corresponding to the type of communication, not limited to the communication protocol, may also be specified in the IE within the signal. This allows the base station device 101 to appropriately perform congestion avoidance control by restricting access or flow rate for communication of a specific application. Note that the port number information used to specify an application does not have to be the port number actually used in the transport layer. In other words, when specifying a communication protocol, the port number actually used may be stored in the IE, and when specifying an application, a port number unused in any communication protocol may be assigned to the application and stored in the IE.

Note that port number assignments may be dynamically changed as long as they are shared between the base station device 101 and the terminal device 102. In one example, if the base station device 101 receives a signal from the terminal device 102 in which a port number that does not correspond to any application is set in the IE, the base station device 101 may block the signal. In this way, the base station device 101 can reduce the load on downstream devices, such as the core network device 103, by not forwarding signals that do not have an appropriate value set in the port number IE.

In the above example, the processing when a call is made from the terminal device 102 was described, but similar processing can also be performed when a call is received from the terminal device 102. Conventionally, when the base station device 101 receives a paging message from the core network device 103 indicating that the terminal device 102 should be called, it is unable to identify the communication protocol used for the communication to be performed by the terminal device 102. In contrast, according to this embodiment, an information element indicating a port number corresponding to an application layer communication protocol is stored in the paging message notified by the core network device 103. Note that the paging message is an example of a message whose contents the base station device 101 can recognize (decode), and other signals may also be used. That is, in order for the base station device 101 to regulate the flow rate when transferring data to a device downstream of the base station device 101, the core network device 103 notifies the base station device 101 of the communication protocol used for the signal that the terminal device plans to transmit. An information element indicating a port number corresponding to an application layer communication protocol may be transmitted in various messages or signals, as long as the message is capable of making this notification. This information element may be, for example, a medium access control (MAC) layer information element. However, this is not limited to this. For example, this information element may be any information element of a communication layer that the base station device 101 can analyze, such as a physical (PHY) layer, a radio link control (RLC) layer, or a packet data convergence protocol (PDCP) layer. This allows the base station device 101 to identify the communication protocol used for the communication calling the terminal device 102. The base station device 101 can then control the data flow rate by, for example, suspending or discarding paging depending on the communication protocol. For example, when the base station device 101 receives a paging message with port number 5060 set, it can identify that the core network device 103 is attempting to call the terminal device 102 for SIP communication. As described above, the port number corresponding to the type of communication, not limited to the communication protocol, may be specified in the IE in the signal. Furthermore, port number allocation may be dynamically changed as long as it is shared between the base station device 101 and the core network device 103. In one example, if the base station device 101 receives a signal from the core network device 103 in which a port number that does not correspond to any application is set in the IE, the base station device 101 may block the signal.

(Device configuration)
Next, the device configuration will be described. FIG. 3 shows an example of the hardware configuration of the base station device and terminal device of this embodiment. In one example, the base station device and terminal device are configured to include a processor 301, a ROM 302, a RAM 303, a storage device 304, and a communication circuit 305. The processor 301 is a computer configured to include one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and performs the overall processing of the device and each of the above-mentioned processes by reading and executing programs stored in the ROM 302 and the storage device 304. The ROM 302 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the base station device and terminal device. The RAM 303 functions as a workspace when the processor 301 executes a program and is also a random access memory that stores temporary information. The storage device 304 is configured, for example, by a removable external storage device. The communication circuit 305 is configured, for example, by a circuit for LTE or 5G wireless communication. Although FIG. 3 illustrates one communication circuit 305, the base station apparatus and the terminal apparatus may have multiple communication circuits. For example, the base station apparatus and the terminal apparatus may have wireless communication circuits for LTE, 5G, and successor standards, respectively, and a common antenna for these circuits. The base station apparatus and the terminal apparatus may also have separate antennas suitable for each standard. The base station apparatus may also have a wired communication circuit used when communicating with other base station apparatuses or core network nodes. The terminal apparatus may also have a communication circuit conforming to a wireless communication standard other than the cellular communication standard, such as a wireless local area network (LAN) or Bluetooth (registered trademark). The base station apparatus and the terminal apparatus may have separate communication circuits 305 for each of the multiple available frequency bands, or may have a common communication circuit 305 for at least some of these frequency bands.

Figure 4 shows an example of the functional configuration of a base station device. The base station device includes, for example, an access control unit 401, a signal receiving unit 402, a communication protocol identification unit 403, and a communication control unit 404. Note that Figure 4 only shows functions particularly relevant to this embodiment, and omits other functions that the base station device may have. For example, the base station device naturally has other functions that are generally possessed by base station devices compliant with 5G or its successor standards. The functional blocks in Figure 4 are shown schematically, and the functional blocks may be integrated or further subdivided. Each function in Figure 4 may be realized, for example, by the processor 301 executing a program stored in the ROM 302 or the storage device 304, or by a processor within the communication circuit 305 executing predetermined software. The details of the processing performed by each functional unit will not be described here; only their general functions will be outlined.

The access restriction unit 401 performs access restriction processing based on the access class and access category. For example, the access restriction unit 401 sets a restriction rate for a specified access class or access category, and broadcasts a notification signal containing information about the restriction rate. Note that the access restriction unit 401 is optional, and access restriction based on the access class or access category does not necessarily have to be performed.

The signal receiving unit 402 receives a signal from the terminal device 102. Here, the signal is, for example, a connection request signal, but it may also be other control signals. In some cases, each signal may also be a data signal. The connection request signal may be, for example, an RRC Connection Request message requesting the establishment of a connection in the Radio Resource Control (RRC) layer. The signal receiving unit 402 may also receive a predetermined message from the core network device 103. Here, the predetermined message may be, for example, a paging message. However, this is just one example, and the predetermined message may also be another control message for requesting the terminal device currently connected to the base station device 101 to transmit predetermined data.

The communication protocol identification unit 403 references an IE that stores information indicating a port number, which is included in a signal received by the signal receiving unit 402 from the terminal device 102 or a message received from the core network device 103. The communication protocol identification unit 403 then identifies, from the value stored in the IE, the communication protocol to be used for transmitting data associated with the signal or message. For example, if the port number is set to 5060, the communication protocol identification unit 403 can identify that the received signal or message is a SIP-related signal or message. The communication protocol identification unit 403 can also identify, not only the communication protocol but also the application for which the communication is being performed, based on the port number. For example, a port number that is not assigned to other applications or communication protocols (i.e., not used for communication) may be assigned to a specific application such as an OS update. When the communication protocol identification unit 403 receives a signal that includes an IE that stores the port number, it can identify that the signal is for an OS update.

The communication control unit 404 determines whether or not to forward a signal received from the terminal device 102 by the signal receiving unit 402 to a downstream device based on the communication protocol and application type identified by the communication protocol identification unit 403. For example, to avoid congestion, if the communication control unit 404 determines that a signal for SIP communication or an OS update has been received, it may block the communication without forwarding the signal to the downstream device. Furthermore, if the communication control unit 404 receives a signal including an IE containing a port number that is not assigned to any application or communication protocol, it may determine that the signal is not an appropriate signal and block the communication without forwarding it to the downstream device. This prevents unauthorized signals, such as DDOS attacks, from being forwarded to downstream devices, preventing unnecessary increases in network load.

Furthermore, the communication control unit 404 may control whether or not to execute communication corresponding to a message received from the core network device 103 in the signal receiving unit 402 with the terminal device 102, based on the communication protocol and type of application identified by the communication protocol identification unit 403. The communication control unit 404 may also control the timing of execution of communication corresponding to a message received from the core network device 103 in the signal receiving unit 402. That is, for example, when the communication control unit 404 receives a paging message from the core network device 103 to call the terminal device 102, the communication control unit 404 may perform control so as not to transmit a paging channel to the terminal device 102. Furthermore, even when the communication control unit 404 transmits the paging channel, it may delay the transmission timing. For example, the communication control unit 404 may start a timer (Paging Discard Timer) that measures the time until a paging message is discarded when the paging message is received from the core network device 103, and transmit a paging channel in the paging occasion (PO) subframe of the terminal device 102 immediately before the timer expires. Note that this is just one example, and the communication control unit 404 may determine the timing of transmitting the paging channel depending on the load status within the base station device 101 or the load status of the network notified, for example, from the core network device 103, and may discard the paging message without transmitting the paging channel as necessary.

In this way, the communication control unit 404 can perform detailed traffic flow control depending on the communication protocol or application related to the received signal. Furthermore, in one example, when a signal is transmitted from the terminal device 102 without being affected by communication restrictions based on the access class or access category imposed by the access restriction unit 401, the communication control unit 404 can determine whether communication based on that signal should be restricted and can perform access restrictions as necessary. This allows for more advanced network access restrictions or traffic flow restrictions to be performed by combining restrictions on the terminal device 102 side using the access class or access category with restrictions on the base station device 101 (network) side based on the type of communication protocol or application.

Figure 5 shows an example of the functional configuration of a terminal device. The terminal device includes, for example, an access control unit 501, a port information identification unit 502, and a signal transmission unit 503. Note that Figure 5 only shows functions particularly relevant to this embodiment, and does not illustrate various other functions that the terminal device may have. For example, the terminal device naturally has other functions that terminal devices compliant with 5G or subsequent standards generally have. Furthermore, the functional blocks in Figure 5 are shown schematically, and the respective functional blocks may be integrated or further subdivided. Furthermore, each function in Figure 5 may be realized, for example, by the processor 301 executing a program stored in the ROM 302 or the storage device 304, or by a processor within the communication circuit 305 executing specific software. Note that the details of the processing performed by each functional unit will not be described here, and only their general functions will be outlined.

The access control unit 501 performs access control based on access classes and access categories. For example, the access control unit 501 may determine whether the terminal device 102 is permitted to transmit a connection request signal based on the access class and access category set in the terminal device 102 and information such as a restriction rate included in a notification signal broadcast from the base station device 101. The access control unit 501 may transmit the connection request signal only if it determines that transmission of the connection request signal is permitted. The access control unit 501 may also transmit control signals other than the connection request signal. The port information identification unit 502 uses the connection request signal and other control signals to identify the application and communication protocol associated with the communication service requested from the network, and identifies port number information corresponding to the application and communication protocol. Note that the information about the application, communication protocol, and corresponding port number may be fixed. In this case, the terminal device 102 may obtain this information from the network when it previously connected to the network, for example, for location registration upon power-on. Note that the information about the application, communication protocol, and corresponding port number may be dynamically changed. In this case, the base station device 101 may broadcast this information by including it in a notification signal, or may notify the connected terminal device via individual signaling. The signal transmission unit 503 stores the port number identified by the port information identification unit 502 in a specified IE within the connection request signal or other control signal (or in some cases, a data signal), generates a wireless signal, and transmits it to the base station device 101. This port number allows the base station device 101 to identify the communication protocol or application associated with the connection request signal, as described above, enabling detailed access restrictions and traffic flow control.

Figure 6 shows an example of the functional configuration of a core network device. The core network device includes, for example, a port information identification unit 601 and a message transmission unit 603. Note that Figure 6 only shows functions particularly relevant to this embodiment, and does not illustrate various other functions that the core network device may have. For example, the core network device naturally has at least some of the other functions generally included in core networks compliant with 5G and subsequent standards. The functional blocks in Figure 6 are shown schematically, and the functional blocks may be integrated or further subdivided. Each function in Figure 6 may be implemented, for example, by processor 301 executing a program stored in ROM 302 or storage device 304, or by a processor within communication circuit 305 executing specified software. The details of the processing performed by each functional unit will not be described here; only their general functions will be outlined.

The port information identification unit 601 identifies the application and communication protocol associated with the communication service to be provided to the terminal device, and identifies port number information corresponding to that application and communication protocol. For example, when calling a terminal device, the port information identification unit 601 identifies which communication service the call is based on. The port information identification unit 601 may identify the port number corresponding to the application and communication protocol, for example, by referencing a lookup table prepared in advance. Note that if the information on the application, communication protocol, and corresponding port number changes dynamically, the core network device 103 may exchange that information with the base station device 101. The message transmission unit 602 generates a paging message or other message including a predetermined IE that stores the port number identified by the port information identification unit 601, and transmits it to the base station device 101. This port number allows the base station device 101 to identify which communication protocol, application, etc. the terminal device 102 will be communicating with (transmitting a signal to) correspond to. Based on the results of this identification, the base station device 101 can then perform detailed access restrictions, traffic flow control, and other similar functions.

(Processing flow)
Next, an example of the processing flow executed in the wireless communication system according to this embodiment will be outlined using Figures 7 and 8. The processing in Figure 7 shows an example of the processing flow when a terminal device stores port number information in a connection request signal and transmits it, and the processing in Figure 8 shows an example of the processing flow when a core network device stores port number information in a paging message and transmits it. Note that these procedures are merely examples, and port number information corresponding to the communication protocol used in the communication executed by the terminal device or the type of application using that communication may be stored and transmitted in other signals or messages. Furthermore, the following description mainly shows procedures related to the technique according to this embodiment, and naturally, processing other than these procedures may also be performed. Furthermore, some of the procedures shown below may be omitted or replaced with other processing of a similar purpose.

In the process of Figure 7, the base station device broadcasts a notification signal to the terminal device (S701) and performs control such as suppressing the transmission of connection request signals by the terminal device based on, for example, the access class or access category. Note that this is just one example, and access restriction based on the access class or access category does not have to be performed. The terminal device transmits a connection request signal (S702). Here, for example, the terminal device transmits a connection request signal in order to originate a SIP voice call. In this case, the terminal device stores 5060, the transport layer port number used in SIP, in a specified IE within the connection request signal and transmits it. When the base station device receives this connection request signal, it can identify the port number stored in the IE and recognize that SIP communication is being performed based on this connection request signal. Note that an IE storing a port number may be included in the signal only if access restriction based on the access class or access category is performed; if such access restriction is not performed, this IE may be omitted. Also, because SIP is used here, the port number is set to 5060, but communication protocols or applications other than SIP may be used, and for this reason a port number other than 5060 may be included in the connection request signal. Also, the connection request signal is merely one example of a signal transmitted from a terminal device to a base station device, and other control signals or data signals may be used instead of the connection request signal.

Based on this connection request signal, the base station device establishes a connection with the terminal device (S703), and a connection is also established between the core network device and the terminal device (S704). The base station device may reject the connection request if, for example, it decides not to accept SIP communications at this point. In this case, the processing ends without establishing a connection between the terminal device and the base station device or core network device. In this way, the base station device can perform access control according to the network load by determining whether to allow or deny access to the network depending on the communication protocol and type of application.

After establishing a connection with the base station and core network device, the terminal device begins sending a SIP message (S705). Normally, when a base station receives a SIP message, it treats it as a simple data call and forwards it to the core network device. In contrast, in this embodiment, the base station device is able to identify in S702 that the signal from the terminal device is a SIP message. Therefore, the base station device can, for example, control the flow rate of SIP traffic (S706) to prevent unnecessarily large numbers of SIP messages from being forwarded to the IMS (S707).

While the above process describes an example in which a terminal device transmits a connection request signal when it is not connected to a base station device, this is not limiting. For example, a process similar to the above may be performed when a terminal device connected to a base station device attempts to start communication using a specific application separate from the currently running communication. In this case, an information element storing a port number value may be included in the data signal or session addition request signal. The base station device may then determine whether to allow or deny the addition of a new session or regulate the traffic flow of that session based on the communication protocol or application type corresponding to the port number. When multiple types of communication are being performed, the above-mentioned port number information may be included in the data signal transmitted from the terminal device. In this case, the base station device may analyze the received data signal each time and regulate the flow rate according to the communication protocol or application type. Furthermore, when multiple types of communication are being performed, a radio bearer may be set for each communication protocol or application type, and traffic flow rate regulation may be performed for each radio bearer. In this case, the port number information does not need to be included in the data signal transmitted from the terminal device.

In the process of Figure 8, the core network device transmits a paging message to the base station device to call the terminal device (S801). Here, this paging message includes an IE that stores a port number, which makes it possible to identify the communication protocol used in the communication that calls the terminal device. Since SIP is used here, the port number is set to 5060. However, this is not limited to this, and if a communication protocol or application other than SIP is used, a port number other than 5060 may be included in the paging message. Furthermore, the paging message is merely one example of a message transmitted from the core network device to the base station device, and other messages may be used instead of the paging message.

When a base station device receives a paging message, it sets a timer to measure the time until it discards the paging message (S802). Typically, the base station device repeatedly transmits a paging channel (PCH) addressed to a terminal device at a timing (paging occasion (PO) subframe) when the terminal device can receive the PCH until a connection with the terminal device is established. The base station device then discards the paging message received from the core network device when the timer expires without a successful call, for example, because the terminal device is unable to receive the PCH due to a physical channel problem. Meanwhile, in this embodiment, the base station device performs paging flow rate regulation to suppress the transmission of SIP-related paging messages, for example, when it is desired to suppress SIP traffic (S803). For example, when the base station device receives a paging message with the port number IE set to 5060 in S801, it may transmit the PCH for SIP communication by the terminal device less frequently than if paging flow rate regulation were not performed. In one example, the base station device may lengthen the transmission period of the PCH addressed to the terminal device or delay the transmission of the PCH addressed to the terminal device. Alternatively, the base station device may discard the paging message received in S801 without transmitting the PCH addressed to the terminal device. The terminal device checks the PCH addressed to the terminal device in the PO subframe (S804) and determines whether the terminal device is being paged. Specifically, the base station device broadcasts a paging message including a Paging-Radio Network Temporary Identifier (P-RNTI), and the terminal device receives the message. The terminal device then uses the P-RNTI to decode the physical downlink control channel (PDCCH) and the physical downlink shared channel (PDSCH) to determine whether the PCH addressed to the terminal device is included in the PDSCH. If a PCH addressed to the terminal device is included, the terminal device extracts the PCH data from the PDSCH; if a PCH addressed to the terminal device is not included, the terminal device discards the PCH addressed to other terminal devices included in the PDSCH.

In the process of Figure 8, the base station device transmits a PCH for the terminal device in the PO subframe observed by the terminal device immediately before the timer set in S802 expires (S805), and does not transmit the PCH in other PO subframes. The base station device may transmit the PCH to the terminal device at an earlier timing, depending on, for example, the amount of SIP-related traffic. In some cases, the base station device may discard the paging message received in S801 without transmitting the PCH to the terminal device. Upon receiving the PCH, the terminal device establishes a connection between the base station device and the core network device (S806, S807), enabling communication of SIP messages (S808). When transmitting SIP messages, the base station device may forward only some messages to subsequent devices, as described in connection with Figure 7. The base station device may also forward SIP messages received from the network side directly to the terminal device. The above process enables appropriate flow regulation, for example, when congestion occurs due to communication by a specific application, such as SIP communication.

As described above, this embodiment enables a base station device to identify the communication protocol used in a signal received from a terminal device and the application for which that signal is intended, and enables advanced traffic flow control based on the results of this identification. This makes it possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which states, "Build resilient infrastructure, promote sustainable industrialization, and foster innovation."

The invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the invention.

Claims (13)

A terminal device of a cellular communication system ,
a specifying means for specifying a port number corresponding to a type of application or a communication protocol executed through communication with a base station device of the cellular communication system ;
a transmitting means for transmitting to the base station device a radio signal including an information element storing the port number, the information element being used for access control to a network by the base station device;
A terminal device comprising: The terminal device according to claim 1, characterized in that the identification means identifies, as the port number, a port number of a transport layer used in the communication protocol. The terminal device according to claim 1, further comprising an acquisition means for acquiring the port number corresponding to the application type or the communication protocol from the network or from the base station device when previously connected to the network. The terminal device according to claim 1, wherein the wireless signal is a connection request signal. A base station device of a cellular communication system ,
receiving means for receiving, from a terminal device of the cellular communication system , a radio signal including an information element storing a port number corresponding to a type of application or a communication protocol executed by the terminal device through communication with the base station device;
an identification means for identifying the type of the application or the communication protocol based on the port number;
a control means for controlling access to a network based on the result of identifying the type of application or the communication protocol;
A base station device comprising: The base station device according to claim 5, wherein the identification means identifies the communication protocol based on the transport layer port number stored as the port number. The base station device according to claim 5, further comprising a notification means for notifying the terminal device of the port number corresponding to the application type or the communication protocol. The base station device according to claim 7, characterized in that the notification means notifies the terminal device of the port number corresponding to the application type or the communication protocol by broadcast transmission. The base station device according to claim 5, wherein the radio signal is a connection request signal. 1. A control method executed by a terminal device of a cellular communication system , comprising:
Identifying a port number corresponding to a type of application or a communication protocol to be executed through communication with a base station device of the cellular communication system ;
transmitting, to the base station device, a radio signal including an information element storing the port number, the information element being used for controlling access to a network by the base station device;
A control method comprising: A control method executed by a base station device of a cellular communication system , comprising:
receiving, from a terminal device of the cellular communication system , a radio signal including an information element storing a port number corresponding to a type of application or a communication protocol executed by the terminal device through communication with the base station device;
Identifying the type of the application or the communication protocol based on the port number;
controlling access to a network based on the result of identifying the type of application or the communication protocol;
A control method comprising: A computer provided in a terminal device of a cellular communication system ,
identifying a port number corresponding to a type of application or a communication protocol to be executed through communication with a base station device of the cellular communication system ;
transmitting, to the base station device, a radio signal including the information element storing the port number, the information element being used for controlling access to the network by the base station device;
Program for. A computer provided in a base station device of a cellular communication system ,
receiving, from a terminal device of the cellular communication system , a wireless signal including an information element storing a port number corresponding to a type of application or a communication protocol executed by the terminal device through communication with the base station device;
Identifying the type of the application or the communication protocol based on the port number;
controlling access to the network based on the result of identifying the type of application or the communication protocol;
Program for.