Communication method and communication device

Abstract

The present application provides a communication method and a communication device for avoiding paging errors caused by unauthorized updates of a terminal device, enhancing a paging early indication (PEI) function performed by the terminal device based on first information, and reducing power consumption of the terminal device. In the method, the terminal device receives a first message, and if access stratum (AS) security between the terminal device and a network device is not activated, the terminal device determines not to update the first information, where the first information indicates a last-used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The terminal device releases the RRC connection.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202210957685.3, entitled "Communication Method and Communication Apparatus," filed with the State Intellectual Property Office of the People's Republic of China on August 10, 2022, which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of communications, and in particular to communication methods and devices. [Background technology]

[0003] In a communication system, when multiple terminal devices monitor the same paging occasion (PO), if paging is performed on only some of the terminal devices, the terminal devices that are not paged will receive unnecessary paging, resulting in unnecessary power consumption. This case is called a paging false alarm.

[0004] Currently, in order to reduce the occurrence of paging false alarms, a paging early indication (PEI) mechanism can be introduced into network devices and terminal devices. The network device can divide multiple terminal devices on the same PO into multiple groups, and based on the PEI mechanism, indicate that terminal devices in some groups specified by the multiple groups need to monitor paging messages on the PO.

[0005] In addition, in the implementation process of the PEI mechanism, the terminal device needs to receive the broadcast message of the camped cell, and determine whether the PEI mechanism is allowed to be used in the camped cell based on the last used cell of the terminal device, in order to reduce unnecessary power consumption.

[0006] However, for a terminal device, how to determine the final use cell of the terminal device is an urgent technical problem to be solved. Summary of the Invention [Means for solving the problem]

[0007] The present application provides a communication method and a communication apparatus for avoiding paging errors caused by unauthorized updates of a terminal device, enhancing a PEI function implemented by the terminal device based on first information, and reducing power consumption of the terminal device.

[0008] A first aspect of the present application provides a communication method. The method may be executed by a terminal device, or may be executed by a component (e.g., a processor, a chip, or a chip system) within the terminal device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the terminal device. In the first aspect and possible implementations thereof, an example in which the communication method is executed by the terminal device is used for explanation. In the method, the terminal device receives a first message. If access stratum (AS) security between the terminal device and the network device is not activated, the terminal device determines not to update first information, the first information indicates a last-used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The terminal device releases the RRC connection.

[0009] Based on the above technical solution, the terminal device can maintain first information indicating the terminal device's last-used cell. In a scenario in which the terminal device receives a first message indicating the release of the RRC connection between the terminal device and the network device and releases the RRC connection, if access stratum security between the terminal device and the network device is not activated, the terminal device determines not to update the first information. If access stratum security is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in a manner in which the terminal device determines not to update the first information, the terminal device does not update the first information based on the cell from which the first message was transmitted (the cell is located in one or more cells corresponding to the network device), thereby avoiding paging errors caused by unauthorized updates of the terminal device, enhancing the PEI function implemented by the terminal device based on the first information, and reducing the power consumption of the terminal device.

[0010] In addition, if access layer security between the terminal device and the network device is not activated, the connection between different network devices (access network device and core network device) may not be successfully established. In this case, the network device cannot update the information maintained by the network device, which is information about the terminal device's last used cell. In consideration of this, in the above technical solution, the terminal device decides not to update the first information, so that the terminal device and the network device maintain the information about the terminal device's last used cell in a consistent manner (also called an aligned manner). In this case, the terminal device and the network device can successfully communicate with each other using the PEI mechanism.

[0011] In addition, if the access stratum security between the terminal device and the network device is not activated, the network device may be an abnormal network device (e.g., a pseudo base station). In consideration of this, in the above technical solution, the terminal device determines not to update the first information, so that the terminal device can be prevented from illegally updating the last-used cell as an illegal cell. In this case, the terminal device and the network device can communicate with each other normally using the PEI mechanism.

[0012] It should be understood that when the terminal device releases the RRC connection, the terminal device may exit the RRC connected mode and the terminal device may enter a state other than the RRC connected mode, for example, an idle state or an inactive state.

[0013] In the present application, the message name of the first message indicating the release of the RRC connection between the terminal device and the network device may be an RRC Release (RRCRelease) message, and the name is the name in the current communication system. In the future communication system, the name of the message indicating the release of the RRC connection between the terminal device and the network device may change with the evolution of the communication system.

[0014] Additionally, in this application, the last used cell of a terminal device may be referred to as the most recently accessed cell of the terminal device, the cell most recently accessed by the terminal device, the cell from which the connection of the terminal device is released, the cell from which the first message is sent to the terminal device, the cell last served by the terminal device, etc.

[0015] Optionally, the terminal device determining not to update the first information may be expressed as the terminal device not updating the first information, or may be expressed as the terminal device determining not to update the first information without identifying whether the first message carries instruction information indicating to update (or not update) the first information, or may be expressed as the terminal device not performing an update of the first information, or may be expressed as the terminal device keeping the first information unchanged, or may be expressed as the first information maintained by the terminal device remaining unchanged.

[0016] In a possible implementation example of the first aspect, the first message includes first instruction information, the first instruction information indicating not to update the first information, and the method further includes a step in which the terminal device ignores the first instruction information if access stratum security between the terminal device and the network device is not activated.

[0017] Based on the aforementioned technical solution, if access stratum security between the terminal device and the network device is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. In consideration of this, the terminal device may ignore the first indication information carried in the first message and determine not to update the first information. In other words, the terminal device can determine not to update the first information without identifying whether the first message carries indication information indicating to update (or not update) the first information, thereby avoiding paging errors caused by unauthorized updates of the terminal device.

[0018] In the present application, the name of the first indication information may be a noLastCellUpdate information element / field / domain / parameter. The name is the name in the current communication system. In the future communication system, the name of the first indication information may change with the evolution of the communication system.

[0019] In a possible implementation of the first aspect, the first message includes second instruction information, the second instruction information indicating a wait time for accessing the network, and the method further includes a step in which the terminal device ignores at least one piece of information in the first message except for the second instruction information, the at least one piece of information including the first instruction information, and the first instruction information indicating not to update the first information.

[0020] Based on the above technical solution, the first message received by the terminal device can include second indication information indicating a waiting time for accessing the network, so that the terminal device can subsequently re-establish a connection to the network device based on the second indication information. In addition, if access stratum security between the terminal device and the network device is not activated, the terminal device can determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, the terminal device can ignore at least one piece of information in the first message except for the second indication information.

[0021] Optionally, the terminal device ignoring at least one piece of information in the first message except for the second instruction information may include the terminal device ignoring information in the first message except for the second instruction information.

[0022] Optionally, the second indication information may alternatively be expressed in other ways, including: the second indication information indicating the time duration of timer T302 (T302 indicating the waiting time for the terminal device to re-establish or resume the RRC connection); the second indication information indicating the waiting time for an access attempt of the terminal device; the second indication information indicating the waiting time for controlling the terminal device to establish the RRC connection.

[0023] In this application, the name of the second indication information may be a waitTime information element / field / domain / parameter. The name is the name in the current communication system. In future communication systems, the name of the second indication information may change with the evolution of the communication system.

[0024] In a possible implementation of the first aspect, the first information includes information about a last used cell of the terminal device.

[0025] Optionally, the first information may include an identifier of a last-use cell of the terminal device. For example, the identifier may be a cell global identifier (CGI) or a physical cell identifier (PCI).

[0026] In a possible implementation example of the first aspect, if any one of the following is met, the terminal device determining that access stratum security between the terminal device and the network device is not activated includes the terminal device determining that a security mode command message is not received, and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed, or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed.

[0027] Based on the above technical solution, the terminal device can determine that the access stratum security between the terminal device and the network device is not activated in the above multiple ways, thereby increasing the flexibility to implement the solution.

[0028] In a possible implementation example of the first aspect, the method further includes a step of the terminal device transmitting first capability information, the first capability information indicating that the terminal device supports the PEI.

[0029] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0030] In a possible implementation example of the first aspect, the method further includes a step of the terminal device receiving third indication information, the third indication information indicating that the network device supports PEI.

[0031] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0032] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0033] A second aspect of the present application provides a communication method. The method may be performed by a network device, or may be performed by a component (e.g., a processor, a chip, or a chip system) within the network device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the network device. In the second aspect and possible implementations thereof, an example in which the communication method is performed by the network device is used for explanation. In the method, the network device sends a first message, and if access stratum security between the terminal device and the network device is not activated, the network device determines not to update second information, the second information indicating one or more cells accessed by the terminal device, and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device. The network device releases the RRC connection.

[0034] Based on the aforementioned technical solution, the network device may maintain second information indicating one or more cells accessed by the terminal device. In a scenario in which the network device transmits a first message indicating the release of the RRC connection between the terminal device and the network device to release the RRC connection, if access stratum security between the terminal device and the network device is not activated, the network device may determine not to update the second information. If access stratum security is not activated, the network device may determine, based on the access stratum security mechanism, that the network device cannot communicate with the terminal device. Therefore, in the manner in which the network device determines not to update the second information, the network device does not update the second information based on the cell from which the first message was transmitted (in this case, the cell is located in one or more cells corresponding to the network device), thereby avoiding paging errors caused by unauthorized updates of the network device, enhancing the PEI function implemented by the network device based on the second information, and reducing the power consumption of the network device.

[0035] In addition, if access layer security between the terminal device and the network device is not activated, the connection between different network devices (access network device and core network device) may not be successfully established. In this case, the network device cannot update the information maintained by the network device, which is information about the terminal device's last used cell. In consideration of this, in the above technical solution, the network device decides not to update the second information, so that the terminal device and the network device maintain the information about the terminal device's last used cell in a consistent manner (also called an aligned manner). In this case, the terminal device and the network device can successfully communicate with each other using the PEI mechanism.

[0036] In addition, if the access stratum security between the terminal device and the network device is not activated, the network device may be an abnormal network device (e.g., a pseudo base station). Therefore, in the above technical solution, the network device determines not to update the second information, so that the network device can be prevented from illegally updating the last-used cell as an illegal cell. In this case, the terminal device and the network device can communicate with each other normally using the PEI mechanism.

[0037] Optionally, the network device determining not to update the second information may be expressed as the network device not updating the second information, or the network device determining not to update the second information without identifying whether the first message carries instruction information indicating to update (or not update) the first information, or the network device not performing an update of the second information, or the network device keeping the second information unchanged, or the second information maintained by the network device remaining unchanged.

[0038] In the present application, the second information indicates one or more cells accessed by the terminal device, and it should be understood that the second information may further indicate other information, for example, one or more cells not accessed by the terminal device, or other information, which is not limited in this specification.

[0039] In a possible implementation example of the second aspect, the first message includes first instruction information, the first instruction information indicating not to update the first information, and the first information indicating a last-used cell of the terminal device, and the method further includes a step in which, if access stratum security between the terminal device and the network device is not activated, the network device determines that the terminal device ignores the first instruction information.

[0040] Based on the aforementioned technical solution, if access stratum security between the terminal device and the network device is not activated, the network device may determine based on the access stratum security mechanism that the network device cannot communicate with the terminal device. In consideration of this, the network device determines that the terminal device will ignore the first indication information, so that the network device and the terminal device are aligned in their understanding of the first information, thereby reducing the possibility of communication errors.

[0041] In a possible implementation example of the second aspect, the first message includes second indication information, the second indication information indicating a waiting time for accessing the network. The method further includes a step of: if access stratum security between the terminal device and the network device is not activated, the network device determining that the terminal device ignores at least one piece of information in the first message except for the second indication information, the at least one piece of information including first indication information, the first indication information indicating not to update the first information, and the first information indicating a last used cell of the terminal device.

[0042] Based on the aforementioned technical solution, the first message sent by the network device may include second indication information indicating a waiting time for accessing the network, so that the terminal device can subsequently re-establish a connection to the network device based on the second indication information. In addition, if access stratum security between the terminal device and the network device is not activated, the network device may determine that the network device cannot communicate with the terminal device based on the access stratum security mechanism. In consideration of this, the network device may determine that the terminal device ignores at least one piece of information in the first message except for the second indication information, so that the network device and the terminal device are aligned in their understanding of the first message, reducing the possibility of communication errors.

[0043] Optionally, the second indication information may alternatively be expressed in other ways, including: the second indication information indicating the time duration of timer T302 (T302 indicating the waiting time for the terminal device to re-establish or resume the RRC connection); the second indication information indicating the waiting time for an access attempt of the terminal device; the second indication information indicating the waiting time for controlling the terminal device to establish the RRC connection.

[0044] In a possible implementation of the second aspect, the method further includes a step in which, if access stratum security between the terminal device and the network device is not activated, the network device determines that the terminal device will not update the first information, wherein the first information indicates a last used cell of the terminal device.

[0045] Based on the aforementioned technical solution, if access stratum security between the terminal device and the network device is not activated, the network device may determine based on the access stratum security mechanism that the network device cannot communicate with the terminal device. In consideration of this, the network device determines that the terminal device will not update the first information, so that the network device and the terminal device are aligned in their understanding of the first information, reducing the possibility of communication errors.

[0046] In a possible implementation of the second aspect, the first information includes information about a last used cell of the terminal device.

[0047] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0048] In a possible implementation of the second aspect, the second information comprises identifiers of one or more cells accessed by the terminal device.

[0049] Optionally, the identifier of the one or more cells accessed by the terminal device may be CGI, PCI, etc.

[0050] In a possible implementation of the second aspect, the network device transmits the second information to the core network device.

[0051] Based on the aforementioned technical solution, the network device can further send second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0052] In a possible implementation of the second aspect, the method further includes a step of the network device receiving first capability information, the first capability information indicating that the terminal device supports PEI.

[0053] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0054] In a possible implementation of the second aspect, the method further includes a step of the network device sending third indication information, the third indication information indicating that the network device supports the PEI.

[0055] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0056] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0057] A third aspect of the present application provides a communication method. The method may be executed by a terminal device, or may be executed by a component (e.g., a processor, a chip, or a chip system) within the terminal device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the terminal device. In the third aspect and possible implementations thereof, an example in which the communication method is executed by a terminal device is used for explanation. In the method, the terminal device receives a first message. If access stratum security between the terminal device and the network device is not activated, the terminal device determines not to ignore first indication information in the first message, or ignores at least one piece of information in the first message except for the first indication information and the second indication information. In this case, the first message indicates that a radio resource control (RRC) connection between the terminal device and the network device is to be released, the first indication information indicates that the first information is not to be updated, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The terminal device releases the RRC connection.

[0058] Based on the above technical solution, the terminal device may maintain first information indicating a last-used cell of the terminal device. In a scenario in which the terminal device receives a first message indicating the release of the RRC connection between the terminal device and the network device and releases the RRC connection, if access stratum security between the terminal device and the network device is not activated, the terminal device may determine not to ignore the first indication information in the first message, or may ignore at least one piece of information in the first message except the first indication information and the second indication information. If access stratum security is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in a manner in which the terminal device decides not to ignore the first instruction information in the first message (or the terminal device ignores at least one piece of information in the first message excluding the first instruction information and the second instruction information), the terminal device does not update the first information based on the cell (in this case, the cell is located in one or more cells corresponding to the network device) from which the first message is transmitted, so that paging errors caused by unauthorized updates of the terminal device can be avoided, the PEI function implemented by the terminal device based on the first information is enhanced, and the power consumption of the terminal device is reduced.

[0059] Additionally, in a manner in which the terminal device decides not to ignore the first instruction information in the first message (or the terminal device ignores at least one piece of information in the first message other than the first instruction information and the second instruction information), the terminal device and the network device are aligned in their understanding of the first instruction information, which can reduce the possibility of communication errors.

[0060] Optionally, the terminal device ignoring at least one information in the first message other than the first instruction information and the second instruction information may include the terminal device ignoring other information in the first message other than the first instruction information and the second instruction information.

[0061] In a possible implementation example of the third aspect, the method further includes the step of the terminal device determining, based on the first indication information, not to update the first information.

[0062] Based on the aforementioned technical solution, the process of determining that the terminal device will not ignore the first indication information may include: the terminal device determining not to update the first information based on the first indication information, so that the terminal device determines not to update the first information based on the first indication information sent by the network device. In this way, the terminal device and the network device are aligned in their understanding of the first indication information, reducing the possibility of communication errors.

[0063] In a possible implementation of the third aspect, the first information includes information about a last used cell of the terminal device.

[0064] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0065] In a possible implementation example of the third aspect, if any one of the following is met, the terminal device determining that access stratum security between the terminal device and the network device is not activated includes the terminal device determining that a security mode command message has not been received, and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed, or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed.

[0066] Based on the above technical solution, the terminal device can determine that the access stratum security between the terminal device and the network device is not activated in the above multiple ways, thereby increasing the flexibility to implement the solution.

[0067] In a possible implementation of the third aspect, the method further includes a step in which the terminal device transmits first capability information, the first capability information indicating that the terminal device supports a paging early notification PEI.

[0068] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0069] In a possible implementation of the third aspect, the method further includes a step of the terminal device receiving third indication information, the third indication information indicating that the network device supports PEI.

[0070] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0071] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0072] A fourth aspect of the present application provides a communication method. The method may be performed by a network device, or may be performed by a component (e.g., a processor, a chip, or a chip system) within the network device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the network device. In the fourth aspect and possible implementations thereof, an example in which the communication method is performed by the network device is used for explanation. In the method, when the network device sends a first message and access stratum security between the terminal device and the network device is not activated, the network device determines not to ignore first indication information in the first message, or the network device ignores at least one piece of information in the first message except for the first indication information and the second indication information, the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The network device releases the RRC connection.

[0073] Based on the aforementioned technical solution, in a scenario in which a network device sends a first message indicating to release the RRC connection between a terminal device and the network device to release the RRC connection, if access stratum security between the terminal device and the network device is not activated, the network device determines not to ignore the first indication information in the first message, or the network device ignores at least one piece of information in the first message except the first indication information and the second indication information. If access stratum security is not activated, the network device can determine based on the access stratum security mechanism that the network device cannot communicate with the terminal device. Therefore, in a manner in which the network device determines not to ignore the first instruction information in the first message (or the network device ignores at least one piece of information in the first message excluding the first instruction information and the second instruction information), the network device determines that the terminal device will not update the first information based on the cell to which the first message is transmitted (in this case, the cell is located in one or more cells corresponding to the network device), thereby enhancing the PEI function implemented by the terminal device based on the first information and avoiding paging errors caused by unauthorized updates of the terminal device to reduce the power consumption of the terminal device.

[0074] Additionally, in a manner in which the network device decides not to ignore the first instruction information in the first message (or the network device ignores at least one piece of information in the first message other than the first instruction information and the second instruction information), the terminal device and the network device are aligned in their understanding of the first instruction information, which can reduce the possibility of communication errors.

[0075] Optionally, the network device ignoring at least one information in the first message except for the first instruction information and the second instruction information may include the network device ignoring information in the first message except for the first instruction information and the second instruction information.

[0076] In a possible implementation example of the fourth aspect, the method further includes a step of the network device determining, based on the first indication information, not to update the second information, wherein the second information indicates one or more cells accessed by the terminal device.

[0077] Based on the aforementioned technical solution, the network device can determine, based on the first indication information, not to update the second information indicating one or more cells accessed by the terminal device, so that the terminal device and the network device are aligned in their understanding of the first indication information, and reduce the possibility of communication errors.

[0078] In a possible implementation of the fourth aspect, the second information comprises identifiers of one or more cells accessed by the terminal device.

[0079] Optionally, the identifier of the one or more cells accessed by the terminal device may be CGI, PCI, etc.

[0080] In a possible implementation of the fourth aspect, the first information includes information about a last used cell of the terminal device.

[0081] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0082] In a possible implementation example of the fourth aspect, the method further includes a step in which, if access stratum security between the terminal device and the network device is not activated, the network device determines that the terminal device will not ignore the first indication information in the first message, or the network device determines that the terminal device will ignore at least one piece of information in the first message excluding the first indication information and the second indication information.

[0083] Based on the aforementioned technical solution, if access stratum security between the terminal device and the network device is not activated, the network device may determine based on the access stratum security mechanism that the network device cannot communicate with the terminal device. In consideration of this, the network device determines that the terminal device will not ignore the first indication information in the first message (or determines that the terminal device will ignore at least one piece of information in the first message other than the first indication information and the second indication information), so that the network device and the terminal device have an aligned understanding of the first information, reducing the possibility of communication errors.

[0084] In a possible implementation of the fourth aspect, the method further comprises the step of the network device transmitting the second information to the core network device.

[0085] Based on the aforementioned technical solution, the network device can further send second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0086] In a possible implementation of the fourth aspect, the method further includes a step of the network device receiving first capability information, the first capability information indicating that the terminal device supports PEI.

[0087] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0088] In a possible implementation of the fourth aspect, the method further includes a step of the network device sending third indication information, the third indication information indicating that the network device supports the PEI.

[0089] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0090] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0091] A fifth aspect of the present application provides a communication method. The method may be executed by a terminal device, or may be executed by a component (e.g., a processor, a chip, or a chip system) within the terminal device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the terminal device. In the fifth aspect and possible implementations thereof, an example in which the communication method is executed by a terminal device is used for explanation. In the method, when the terminal device receives a first message and access stratum security between the terminal device and the network device is not activated, the terminal device processes first information based on the first message, where the first information indicates information about a last-used cell of the terminal device, and the first message indicates releasing a radio resource control (RRC) connection between the terminal device and the network device. The terminal device releases the RRC connection.

[0092] Based on the above technical solution, a terminal device can maintain first information indicating a last-used cell of the terminal device. In a scenario in which the terminal device receives a first message indicating the release of the RRC connection between the terminal device and the network device and releases the RRC connection, the terminal device processes the first information based on the first message. If access stratum security is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in the method in which the terminal device processes the first information based on the first message, the terminal device and the network device are aligned in their understanding of the first message, reducing the possibility of communication errors.

[0093] In a possible implementation example of the fifth aspect, the terminal device processing the first information based on the first message includes, if the first message includes first instruction information, the terminal device determining not to update the first information, wherein the first instruction information indicates not to update the first information.

[0094] Based on the aforementioned technical solution, when the first message includes first instruction information indicating not to update the first information, the terminal device determines not to update the first information, so that the terminal device performs corresponding operations according to the instruction of the network device to reduce the possibility of communication errors.

[0095] In a possible implementation example of the fifth aspect, the terminal device processing the first information based on the first message includes, if the first message does not include first indication information, the terminal device updating the first information based on a cell corresponding to the first message, and the first indication information indicates not to update the first information.

[0096] Based on the aforementioned technical solution, if the first message does not include the first instruction information, the terminal device updates the first information according to the cell corresponding to the first message, so that the terminal device performs corresponding operations according to the instruction of the network device to reduce the possibility of communication errors.

[0097] It should be understood that the process of the terminal device updating the first information based on the cell corresponding to the first message includes, but is not limited to, updating the first information based on the cell identifier of the cell to which the first message is transmitted, or updating the first information based on the cell identifier carried in the first message.

[0098] In a possible implementation of the fifth aspect, the first information includes information about a last used cell of the terminal device.

[0099] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0100] In a possible implementation example of the fifth aspect, if any one of the following is met, the terminal device determining that access stratum security between the terminal device and the network device is not activated includes the terminal device determining that a security mode command message is not received, and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed, or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed.

[0101] Based on the above technical solution, the terminal device can determine that the access stratum security between the terminal device and the network device is not activated in the above multiple ways, thereby increasing the flexibility to implement the solution.

[0102] In a possible implementation example of the fifth aspect, the method further includes a step of the terminal device transmitting first capability information, the first capability information indicating that the terminal device supports the PEI.

[0103] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0104] In a possible implementation example of the fifth aspect, the method further includes a step in which the terminal device receives third indication information, the third indication information indicating that the network device supports PEI.

[0105] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0106] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0107] A sixth aspect of the present application provides a communication method. The method may be performed by a network device, or may be performed by a component (e.g., a processor, a chip, or a chip system) within the network device, or may be implemented by a logic module or software capable of implementing all or part of the functions of the network device. In the sixth aspect and possible implementations thereof, an example in which the communication method is performed by the network device is used for explanation. In the method, the network device transmits a first message, and if access stratum security between the terminal device and the network device is not activated, the network device processes second information based on the first message, the second information indicating one or more cells accessed by the terminal device, and the first message indicating releasing a radio resource control (RRC) connection between the terminal device and the network device. The network device releases the RRC connection.

[0108] Based on the aforementioned technical solution, a network device can maintain second information indicating one or more cells accessed by a terminal device. In a scenario in which the network device releases an RRC connection by transmitting a first message indicating the release of the RRC connection between the terminal device and the network device, the network device processes the second information based on the first message. If access stratum security is not activated, the network device can determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in a method in which the network device processes the first information based on the first message, the terminal device and the network device are aligned in their understanding of the first message, reducing the possibility of communication errors.

[0109] In a possible implementation example of the sixth aspect, the network device processing the second information based on the first message includes the network device determining not to update the second information if the first message includes first instruction information, wherein the first instruction information indicates not to update the first information, and the first information indicates a last used cell of the terminal device.

[0110] Based on the aforementioned technical solution, when the first message includes first instruction information indicating not to update the first information, the network device determines not to update the second information, so that the terminal device then performs corresponding operations based on the instruction of the network device to reduce the possibility of communication errors.

[0111] In a possible implementation example of the sixth aspect, the terminal device processing the first information based on the first message includes, if the first message does not include first indication information, the terminal device updating the second information based on a cell corresponding to the first message, wherein the first indication information indicates not to update the first information, and the first information indicates information regarding a last used cell of the terminal device.

[0112] Based on the aforementioned technical solution, if the first message does not include the first instruction information, the network device updates the second information based on the cell corresponding to the first message, so that the terminal device then performs corresponding operations based on the instruction of the network device, thereby reducing the possibility of communication errors.

[0113] It should be understood that the process in which the terminal device updates the first information based on the cell corresponding to the first message includes the terminal device updating the first information based on the cell identifier of the cell from which the first message is transmitted, or the terminal device updating the first information based on the cell identifier carried in the first message. This is not limited in this specification. For example, in the above-mentioned embodiment, the terminal device updates the first information based on the cell identifier of the cell from which the first message is transmitted. In other words, the terminal device updates the information about the last-used cell indicated by the first information as the cell identifier of the cell from which the first message is transmitted.

[0114] In a possible implementation example of the sixth aspect, the first information includes information about a last used cell of the terminal device.

[0115] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0116] In a possible implementation example of the sixth aspect, the second information comprises identifiers of one or more cells accessed by the terminal device.

[0117] Optionally, the identifier of the one or more cells accessed by the terminal device may be CGI, PCI, etc.

[0118] In a possible implementation of the sixth aspect, the method further includes the step of the network device transmitting the second information to the core network device.

[0119] Based on the aforementioned technical solution, the network device can further send second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0120] In a possible implementation example of the sixth aspect, the method further includes the step of the network device determining, based on the first message, whether the terminal device updates the first information.

[0121] Based on the aforementioned technical solution, the network device can further determine whether the terminal device updates the first information based on the first message, so that the network device determines the behavior of the terminal device to avoid communication errors.

[0122] In a possible implementation example of the sixth aspect, the method further includes a step of the network device receiving first capability information, the first capability information indicating that the terminal device supports PEI.

[0123] Based on the aforementioned technical solution, the terminal device can send first capability information indicating that the terminal device supports PEI to the network device, so that the network device determines based on the first capability information that the terminal device supports PEI, and communicates with the terminal device based on the PEI mechanism.

[0124] In a possible implementation example of the sixth aspect, the method further includes a step of the network device sending third indication information, the third indication information indicating that the network device supports the PEI.

[0125] Based on the aforementioned technical solution, the network device can send third indication information to the terminal device, indicating that the network device supports PEI, so that the terminal device determines, based on the third indication information, that the network device supports PEI, and communicates with the network device based on the PEI mechanism.

[0126] Optionally, in addition to the above-mentioned embodiment of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another embodiment. For example, in one embodiment of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0127] A seventh aspect of the present application provides a communication device. The device can implement the method of the first aspect or any one of the possible implementations of the first aspect. The device includes corresponding units or modules configured to execute the aforementioned method. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a terminal device, or a component (e.g., a processor, a chip, or a chip system) within the terminal device, or a logic module or software capable of implementing all or part of the functions of the terminal device. In the seventh aspect and possible implementations of the seventh aspect, an example in which the communication device is a terminal device is used for explanation.

[0128] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit determines not to update first information, the first information indicates a last used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit releases the RRC connection.

[0129] In a possible implementation example of the seventh aspect, the first message includes first indication information, and the first indication information indicates not to update the first information. If access stratum security between the terminal device and the network device is not activated, the processing unit is further configured to ignore the first indication information.

[0130] In a possible implementation example of the seventh aspect, the first message includes second instruction information, the second instruction information indicating a waiting time for accessing the network, and the processing unit is further configured to ignore at least one piece of information in the first message except for the second instruction information, the at least one piece of information including the first instruction information, the first instruction information indicating not to update the first information.

[0131] In a possible implementation example of the seventh aspect, the first information includes information about a last used cell of the terminal device.

[0132] In a possible implementation example of the seventh aspect, if any one of the following is met, the processing unit determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit determining that a security mode command message is not received; and after the transceiver unit receives the security mode command message, the processing unit determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit receives the security mode command message, the processing unit determining that integrity protection verification corresponding to the security mode command message has failed.

[0133] In a possible implementation example of the seventh aspect, the transceiver unit is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0134] In a possible implementation example of the seventh aspect, the transceiver unit is further configured to receive third indication information, the third indication information indicating that the network device supports the PEI.

[0135] In a seventh aspect of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementations of the first aspect and achieve corresponding technical effects. For details, please refer to the first aspect. Details will not be described again in this specification.

[0136] An eighth aspect of the present application provides a communication device. The device can implement the method of the second aspect or any one of the possible implementations of the second aspect. The device includes corresponding units or modules configured to execute the aforementioned method. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a network device, or a component (e.g., a processor, a chip, or a chip system) within a network device, or a logic module or software capable of implementing all or part of the functions of a network device. In the eighth aspect and possible implementations of the eighth aspect, an example in which the communication device is a network device is used for explanation.

[0137] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit transmits a first message and access stratum security between the terminal device and the network device is not activated, the processing unit determines not to update second information, the second information indicating one or more cells accessed by the terminal device, and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit releases the RRC connection.

[0138] In a possible implementation example of the eighth aspect, the first message includes first instruction information, the first instruction information indicates not to update the first information, and the first information indicates a last used cell of the terminal device. If access stratum security between the terminal device and the network device is not activated, the processing unit determines that the terminal device ignores the first instruction information.

[0139] In a possible implementation example of the eighth aspect, the first message includes second indication information, and the second indication information indicates a waiting time for accessing the network. If access stratum security between the terminal device and the network device is not activated, the processing unit determines that the terminal device ignores at least one piece of information in the first message except for the second indication information, and the at least one piece of information includes first indication information, and the first indication information indicates not to update the first information, and the first information indicates a last used cell of the terminal device.

[0140] In a possible implementation example of the eighth aspect, if access stratum security between the terminal device and the network device is not activated, the processing unit determines that the terminal device does not update the first information, and the first information indicates a last used cell of the terminal device.

[0141] In a possible implementation example of the eighth aspect, the first information includes information regarding a last used cell of the terminal device.

[0142] In a possible implementation example of the eighth aspect, the second information comprises identifiers of one or more cells accessed by the terminal device.

[0143] In a possible implementation example of the eighth aspect, the transceiver unit is further configured to transmit the second information to the core network device.

[0144] In a possible implementation example of the eighth aspect, the transceiver unit is further configured to transmit third indication information, wherein the third indication information indicates that the network device supports the PEI.

[0145] In an eighth aspect of the embodiment of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementation of the second aspect and achieve the corresponding technical effect. For details, please refer to the second aspect. The details will not be described again in this specification.

[0146] A ninth aspect of the present application provides a communication device. The device can implement the method of the third aspect or any one of the possible implementations of the third aspect. The device includes corresponding units or modules configured to execute the aforementioned methods. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a terminal device, or a component (e.g., a processor, a chip, or a chip system) within the terminal device, or a logic module or software capable of implementing all or part of the functions of the terminal device. In the ninth aspect and possible implementations of the ninth aspect, an example in which the communication device is a terminal device is used for explanation.

[0147] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit determines not to ignore first indication information in the first message, or the processing unit ignores at least one piece of information in the first message except for the first indication information and second indication information, where the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The processing unit releases the RRC connection.

[0148] In a possible implementation example of the ninth aspect, the processing unit is further configured to determine, based on the first indication information, not to update the first information.

[0149] In a possible implementation example of the ninth aspect, the first information includes information regarding a last used cell of the terminal device.

[0150] In a possible implementation example of the ninth aspect, if any one of the following is met, the processing unit determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit determining that a security mode command message is not received; and after the transceiver unit receives the security mode command message, the processing unit determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit receives the security mode command message, the processing unit determining that integrity protection verification corresponding to the security mode command message has failed.

[0151] In a possible implementation example of the ninth aspect, the transceiver unit is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0152] In a possible implementation example of the ninth aspect, the transceiver unit is further configured to receive third indication information, the third indication information indicating that the network device supports the PEI.

[0153] In a ninth aspect of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementations of the third aspect and achieve corresponding technical effects. For details, please refer to the third aspect. The details will not be described again in this specification.

[0154] A tenth aspect of the present application provides a communication device. The device can implement the method of the fourth aspect or any one of the possible implementations of the fourth aspect. The device includes corresponding units or modules configured to execute the aforementioned methods. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a network device, or a component (e.g., a processor, a chip, or a chip system) within a network device, or a logic module or software capable of implementing all or part of the functions of a network device. In the tenth aspect and possible implementations of the tenth aspect, an example in which the communication device is a network device is used for explanation.

[0155] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit is transmitting a first message and access stratum security between the terminal device and the network device is not activated, the processing unit determines not to ignore first indication information in the first message, or the processing unit ignores at least one piece of information in the first message except for the first indication information and second indication information, where the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The processing unit releases the RRC connection.

[0156] In a possible implementation example of the tenth aspect, the processing unit is further configured to determine, based on the first indication information, not to update the second information, wherein the second information indicates one or more cells accessed by the terminal device.

[0157] In a possible implementation of the tenth aspect, the second information comprises identifiers of one or more cells accessed by the terminal device.

[0158] In a possible implementation of the tenth aspect, the first information includes information regarding a last used cell of the terminal device.

[0159] In a possible implementation example of the tenth aspect, when access stratum security between the terminal device and the network device is not activated, the processing unit determines that the terminal device does not ignore the first indication information in the first message, or the processing unit determines that the terminal device ignores at least one piece of information in the first message excluding the first indication information and the second indication information.

[0160] In a possible implementation example of the tenth aspect, the transceiver unit is further configured to transmit the second information to the core network device.

[0161] In a possible implementation example of the tenth aspect, the transceiver unit is further configured to receive first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0162] In a possible implementation example of the tenth aspect, the transceiver unit is further configured to transmit third indication information, wherein the third indication information indicates that the network device supports the PEI.

[0163] In a tenth aspect of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementations of the third aspect and achieve corresponding technical effects. For details, please refer to the third aspect. The details will not be described again in this specification.

[0164] An eleventh aspect of the present application provides a communication device. The device can implement the method of the fifth aspect or any one of the possible implementations of the fifth aspect. The device includes corresponding units or modules configured to execute the aforementioned methods. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a terminal device, or a component (e.g., a processor, a chip, or a chip system) within the terminal device, or a logic module or software capable of implementing all or part of the functions of the terminal device. In the ninth aspect and possible implementations of the ninth aspect, an example in which the communication device is a terminal device is used for explanation.

[0165] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit processes first information based on the first message, the first information indicating information about a last used cell of the terminal device, and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit releases the RRC connection.

[0166] In a possible implementation example of the eleventh aspect, the processing unit processing the first information based on the first message includes the processing unit determining not to update the first information if the first message includes first instruction information, wherein the first instruction information indicates not to update the first information.

[0167] In a possible implementation example of the eleventh aspect, the processing unit processing the first information based on the first message includes, if the first message does not include first instruction information, the processing unit updating the first information based on a cell corresponding to the first message, and the first instruction information indicates not to update the first information.

[0168] In a possible implementation example of the eleventh aspect, the first information includes information regarding a last used cell of the terminal device.

[0169] In a possible implementation example of the eleventh aspect, if any one of the following is met, the processing unit determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit determining that a security mode command message is not received; and after the transceiver unit receives the security mode command message, the processing unit determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit receives the security mode command message, the processing unit determining that integrity protection verification corresponding to the security mode command message has failed.

[0170] In a possible implementation example of the eleventh aspect, the transceiver unit is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0171] In a possible implementation example of the eleventh aspect, the transceiver unit is further configured to receive third indication information, wherein the third indication information indicates that the network device supports the PEI.

[0172] In an eleventh aspect of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementations of the fourth aspect and achieve corresponding technical effects. For details, please refer to the fourth aspect. The details will not be described again in this specification.

[0173] A twelfth aspect of the present application provides a communication device. The device can implement the method of the sixth aspect or any one of the possible implementations of the sixth aspect. The device includes corresponding units or modules configured to execute the aforementioned methods. The units or modules included in the device can be implemented by software and / or hardware. For example, the device can be a network device, or a component (e.g., a processor, a chip, or a chip system) within a network device, or a logic module or software capable of implementing all or part of the functions of a network device. In the twelfth aspect and possible implementations of the twelfth aspect, an example in which the communication device is a network device is used for explanation.

[0174] The apparatus includes a processing unit and a transceiver unit. When the transceiver unit transmits a first message and access stratum security between the terminal device and the network device is not activated, the processing unit processes second information based on the first message, the second information indicating one or more cells accessed by the terminal device, and the first message indicating releasing a radio resource control (RRC) connection between the terminal device and the network device. The processing unit releases the RRC connection.

[0175] In a possible implementation example of the twelfth aspect, the processing unit processing the second information based on the first message includes the processing unit determining not to update the second information if the first message includes first instruction information, the first instruction information indicating not to update the first information, and the first information indicating information regarding a last used cell of the terminal device.

[0176] In a possible implementation example of the twelfth aspect, the processing of the first information based on the first message by the processing unit includes, if the first message does not include first instruction information, the processing unit updating the second information based on a cell corresponding to the first message, wherein the first instruction information indicates not to update the first information, and the first information indicates information regarding a last used cell of the terminal device.

[0177] In a possible implementation example of the twelfth aspect, the first information includes information regarding a last used cell of the terminal device.

[0178] In a possible implementation example of the twelfth aspect, the second information includes identifiers of one or more cells accessed by the terminal device.

[0179] In a possible implementation example of the twelfth aspect, the processing unit determines, based on the first message, whether the terminal device updates the first information.

[0180] In a possible implementation example of the twelfth aspect, the transceiver unit is further configured to receive first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0181] In a possible implementation example of the twelfth aspect, the transceiver unit is further configured to transmit third indication information, wherein the third indication information indicates that the network device supports the PEI.

[0182] In a twelfth aspect of the present application, the configuration module of the communication device may be further configured to perform the steps performed in the possible implementations of the sixth aspect and achieve corresponding technical effects. For details, please refer to the sixth aspect. The details will not be described again in this specification.

[0183] According to a thirteenth aspect, an embodiment of the present application provides a communications device including at least one processor, the at least one processor connected to a memory, the memory configured to store a program or instruction, and the at least one processor configured to execute the program or instruction, such that the device performs a method according to any possible implementation of any one of the first to sixth aspects.

[0184] According to a fourteenth aspect, an embodiment of the present application provides a communication device including at least one logic circuit and an input / output interface, the logic circuit and the input / output interface configured to perform a method according to any possible implementation of any one of the first to sixth aspects.

[0185] According to a fifteenth aspect, an embodiment of the present application provides a computer-readable storage medium storing one or more computer-executable instructions that, when executed by a processor, cause the processor to perform a method according to any possible implementation of any one of the first to sixth aspects.

[0186] According to a sixteenth aspect, an embodiment of the present application provides a computer program product (also called a computer program), which, when executed by a processor, causes the processor to perform a method according to any possible implementation of any one of the first to sixth aspects.

[0187] According to a seventeenth aspect, an embodiment of the present application provides a chip system, the chip system including at least one processor configured to support a communications device in implementing functions in a method according to any possible embodiment of any one of the first to sixth aspects.

[0188] In a possible design, the chip system may further include a memory configured to store instructions and data necessary for programming the communication device. The chip system may include a chip, or may include a chip and other discrete components. Optionally, the chip system further includes an interface circuit, which provides program instructions and / or data to the at least one processor.

[0189] According to an eighteenth aspect, an embodiment of the present application provides a communication system, wherein the communication system includes the terminal device of the first aspect and the network device of the second aspect, or the communication system includes the terminal device of the third aspect and the network device of the fourth aspect, or the communication system includes the terminal device of the fifth aspect and the network device of the sixth aspect.

[0190] Alternatively, the communication system includes a communication device of the seventh aspect and a communication device of the eighth aspect, or the communication system includes a communication device of the ninth aspect and a communication device of the tenth aspect, or the communication system includes a communication device of the eleventh aspect and a communication device of the twelfth aspect, or the communication system includes a communication device of the thirteenth aspect, or the communication system includes a communication device of the fourteenth aspect.

[0191] For the technical effects provided by any one of the design methods of the seventh to eighteenth aspects, please refer to the technical effects provided by any one of the different design methods of the first to sixth aspects, and the details will not be described again in this specification. [Brief explanation of the drawings]

[0192] [Figure 1a] 1 is a diagram of a communication scenario according to the present application; [Figure 1b] FIG. 2 is another diagram of a communication scenario according to the present application. [Figure 1c] FIG. 2 is another diagram of a communication scenario according to the present application. [Figure 2a] FIG. 1 is a diagram of a paging process according to the present application. [Figure 2b] FIG. 2 is another diagram of a paging process according to the present application. [Figure 3a] FIG. 2 is another diagram of a communication scenario according to the present application. [Figure 3b] FIG. 2 is another diagram of a communication scenario according to the present application. [Figure 4] 1 is a diagram of a communication method according to the present application; [Figure 5] FIG. 2 is another diagram of a communication method according to the present application. [Figure 6] FIG. 2 is another diagram of a communication method according to the present application. [Figure 7] FIG. 2 is another diagram of a communication method according to the present application. [Figure 8] FIG. 2 is another diagram of a communication method according to the present application. [Figure 9] 1 is a diagram of a communication device according to the present application; [Figure 10] FIG. 2 is another diagram of a communication device according to the present application. [Figure 11] FIG. 2 is another diagram of a communication device according to the present application. [Figure 12] FIG. 2 is another diagram of a communication device according to the present application. DETAILED DESCRIPTION OF THE INVENTION

[0193] The following clearly and completely describes the technical solutions of the embodiments of the present application with reference to the accompanying drawings of the embodiments of the present application.

[0194] First, in order to facilitate understanding by those skilled in the art, some terms in the embodiments of the present application will be explained and explained.

[0195] (1) Terminal Device: The terminal device may be a wireless terminal device capable of receiving scheduling and instruction information from a network device. The wireless terminal device may be a device that provides a user with voice and / or data connectivity, a handheld device with wireless connectivity, or another processing device connected to a wireless modem.

[0196] Terminal devices can communicate with one or more core networks or the Internet through a radio access network (RAN). Terminal devices can be portable terminal devices such as cell phones (also called "cellular" or mobile phones), computers, and data cards. For example, terminal devices can be portable, pocket-sized, handheld, computer-integrated, or vehicle-mounted mobile devices that exchange voice and / or data with the radio access network. For example, terminal devices can be devices such as personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), tablet computers (Pads), or computers with wireless transceiver capabilities. A wireless terminal device may also be called a system, subscriber unit, subscriber station, mobile station, mobile station (MS), remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, subscriber station (SS), customer premises equipment (CPE), terminal, user equipment (UE), mobile terminal (MT), etc.The terminal device may alternatively be a wearable device and a terminal device of a next generation communication system, for example a terminal device of a 5G communication system or a terminal device of a future evolved public land mobile network (PLMN).

[0197] (2) Network Device: A network device may be a device in a wireless network. For example, a network device may be a radio access network (RAN) node (or device), or may be called a base station through which a terminal device accesses the wireless network. Currently, some examples of RAN devices are a next-generation Node B (gNodeB), a transmission reception point (TRP), an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved Node B or home Node B (HNB)), a base band unit (BBU), a wireless fidelity (Wi-Fi) access point (AP), etc. in a 5G communication system. Additionally, in the network structure, the access network devices may include a centralized unit (CU) node, a distributed unit (DU) node, or a RAN device including a CU node and a DU node.

[0198] The network device may send configuration information (e.g., carried in a scheduling message and / or an instruction message) to the terminal device. The terminal device further performs network configuration based on the configuration information, resulting in alignment of the network configurations of the network device and the terminal device. Alternatively, the network configurations of the network device and the terminal device are aligned through a network configuration pre-configured in the network device and a network configuration pre-configured in the terminal device. Specifically, "alignment" means that when there is an interaction message between the network device and the terminal device, the network device and the terminal device have a consistent understanding of the carrier frequency for transmitting and receiving the interaction message, the determination of the type of the interaction message, the meaning of field information carried in the interaction message, or another configuration of the interaction message.

[0199] In addition, in another possible case, the network device may be another device that provides wireless communication capabilities to the terminal device. The specific technology and the specific device configuration used by the network device are not limited in the embodiments of the present application. For ease of explanation, this is not limited in the embodiments of the present application.

[0200] The network devices may further include core network devices, such as an access and mobility management function (AMF), a user plane function (UPF), or a session management function (SMF).

[0201] In the embodiments of the present application, the apparatus configured to implement the functions of the network device may be a network device, or may be an apparatus, such as a chip system, that can support the network device in implementing the functions. The apparatus may be installed in the network device. In the technical solutions provided in the embodiments of the present application, an example in which the apparatus configured to implement the functions of the network device is a network device is used to describe the technical solutions provided in the embodiments of the present application.

[0202] (3) Radio resource control (RRC) status: A terminal device has at least three RRC statuses: an RRC connected state, an RRC idle state, and an inactive state.

[0203] RRC connected state (also called connected state for short, "connected state" and "RRC connected state" are the same concept and are interchangeable in this application): The terminal device can transmit data to the network after establishing an RRC connection.

[0204] RRC idle state (also called idle state for short, "idle state" and "RRC idle state" are the same concept and are interchangeable in this specification): the terminal device does not establish an RRC connection to the network and the base station does not store the context of the terminal device. If the terminal device needs to enter the RRC connected state from the RRC idle state, the terminal device must first initiate an RRC connection establishment process.

[0205] RRC inactive state (also referred to as inactive state for short, and the terms "inactivated state", "inactivated state", "inactive state", "RRC inactive state", and "RRC inactivated state" are the same concept and are interchangeable in this specification): After the terminal device previously entered the RRC connected state, the base station released the RRC connection, but the base station still stored the context of the terminal device. When the terminal device needs to enter the RRC connected state again from the RRC inactive state, the terminal device needs to initiate an RRC resumption process (also called an RRC connection resumption process). Compared with the RRC setup process, the RRC resumption process has shorter delay and lower signaling overhead. However, the base station needs to store the context of the terminal device, which results in storage overhead for the base station.

[0206] (4) System information (SI) It should be understood that system information is a message sent by a base station and includes information required for UE initialization and information related to some other functions / features. System information is classified into minimum system information (minimum SI) and other system information (other SI, OSI). Minimum system information includes master information block (MIB) and system information block 1 (SIB1). SIB1 is also called remaining minimum system information (RMSI).

[0207] Optionally, the MIB is periodically broadcast on a broadcast channel (BCH). The SIB1 is periodically broadcast on a downlink shared channel (DL-SCH) or is sent to terminal devices in RRC connected mode (RRC_CONNECTED) using dedicated signaling.

[0208] The other system information includes other SIBs such as SIB 2 to SIB 9. The other SIBs are either broadcast periodically on the DL-SCH, or broadcast on-demand on the DL-SCH (i.e., the network device broadcasts the SIBs only if a terminal device in RRC_IDLE or RRC_INACTIVE state requests them; otherwise, the network device does not send them), or are sent to the UE in RRC connected mode using dedicated signaling.

[0209] Optionally, the basic procedure for a terminal device in RRC idle mode and RRC inactive mode to acquire system information is as follows: the terminal device first acquires an MIB, acquires SIB1 based on the scheduling information in the MIB, and then acquires another SIB based on the scheduling information in SIB1.

[0210] Optionally, parameters such as a default paging cycle T, the number of PFs in the paging cycle (N), a PF offset (PF_offset), and the number of POs corresponding to one PF (Ns) are configured in SIB1.

[0211] (5) Configuration and Pre-Configuration: In this application, both configuration and pre-configuration are used. Configuration means that a network device / server sends configuration information or parameter values of some parameters to a terminal using a message or signaling, and as a result, the terminal determines communication parameters or resources to be used for transmission based on the values or information. Similar to configuration, pre-configuration may be parameter information or parameter values pre-negotiated with a terminal device by a network device / server, parameter information or parameter values used by a base station / network device or terminal device and specified in a standard protocol, or parameter information or parameter values pre-stored in a base station / server or terminal device. This is not limited in this application.

[0212] Additionally, these values and parameters may be changed or updated.

[0213] (6) In the embodiments of this application, the terms "system" and "network" may be used interchangeably. "At least one" means one or more, and "multiple" means two or more than two. "And / or" describes a relationship between related objects and indicates that three relationships may exist. For example, A and / or B can indicate three cases: when only A exists, when both A and B exist, and when only B exists, and A and B may be singular or plural. The character " / " typically indicates an "or" relationship between related objects. "At least one of the following items (parts)" or similar expressions refers to any combination of these items, including any combination of a single item (part) or multiple items (parts). For example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC. Additionally, unless otherwise specified, ordinal numbers such as "first" and "second" in the embodiments of this application are used to distinguish between multiple objects and are not used to limit the order, chronology, priority, or importance of the multiple objects.

[0214] In this application, unless otherwise specified, the same or similar parts of the embodiments shall refer to each other. In the embodiments and methods / designs / implementations in the embodiments of this application, unless otherwise specified or logical contradictions arise, the terms and / or descriptions between different embodiments and between the methods / designs / implementations in the embodiments shall be consistent and may be mutually referenced, and different embodiments and technical features in the methods / designs / implementations in the embodiments may be combined to form new embodiments, methods, or implementations based on their internal logical relationships. The following implementation forms of this application shall not constitute limitations on the protection scope of this application.

[0215] Fig. 1a is a diagram of a communication system according to the present application. Fig. 1a shows an example of one network device 101 and six terminal devices. The six terminal devices are terminal device 1, terminal device 2, terminal device 3, terminal device 4, terminal device 5, and terminal device 6. In the example shown in Fig. 1a, an example is used for explanation, in which terminal device 1 is a smart teacup, terminal device 2 is a smart air conditioner, terminal device 3 is a smart fuel dispenser, terminal device 4 is a means of transportation, terminal device 5 is a mobile phone, and terminal device 6 is a printer.

[0216] As shown in FIG. 1a, in the communication process, the signal transmitting device (or called the transmitting end or transmitting end device) may be a network device, and the signal receiving device (or called the receiving end or receiving end device) may be a terminal device, or the signal transmitting device may be a terminal device and the signal receiving device may be a network device, or the signal transmitting device and the signal receiving device may each be a network device, or both the signal transmitting device and the signal receiving device may each be a terminal device.

[0217] This application may be applied to a long term evolution (LTE) system, a new radio (NR) system, or a post-5G evolved communication system (e.g., 6G). The communication system includes at least one network device and / or at least one terminal device.

[0218] In one implementation example, Figure 1b is a diagram of a 5G NR system architecture. The 5G core network (5GC) may include network elements such as an access and mobility management function (AMF) and a user plane function (UPF). The 5G radio access network (NG-RAN) may include network elements such as a 5G access network (denoted as gNB) and a 4G access network (denoted as ng-eNB) connected to the 5GC.

[0219] Optionally, in the example shown in FIG. 1b, the serving base station gNB of the terminal device is responsible for providing the terminal device with 5G NR user plane and control plane protocol functions, and the serving base station ng-eNB of the terminal device is responsible for providing the terminal device with 4G E-UTRA user plane and control plane protocol functions.

[0220] In another implementation example, Figure 1c is a diagram of an architecture of an LTE system. The 4G core network may be an evolved packet core (EPC) and include network elements such as a mobility management entity (MME) and a serving gateway (S-GW). The 4G radio access network may be an E-UTRAN and include network elements such as 4G base stations (denoted as eNBs) and 5G base stations (denoted as en-gNBs) connected to the EPC.

[0221] Optionally, in the example shown in FIG. 1c, the serving base station eNB of the terminal device is responsible for providing the UE with LTE user plane and control plane protocol functions, and the serving base station en-gNB of the terminal device is responsible for providing the terminal device with 5G NR user plane and control plane protocol functions.

[0222] In any of the embodiments shown in Figures 1a to 1c, the network device can initiate paging to the terminal device. Paging means that the network device sends a page to the terminal device at a paging occasion (PO) calculated by the network device, and the terminal device receives the paging message at the same PO. In this way, the purpose of searching for a specific terminal device in the network is achieved.

[0223] Paging also supports discontinuous reception (DRX). In this way, a terminal device can wake up for a certain period of time to receive paging messages and sleep for another period of time, thereby reducing power consumption and extending battery life. For example, each wake-up cycle is a DRX cycle. One DRX cycle includes one or more paging frames (PFs), and one PF corresponds to one or more POs on which one terminal device needs to receive paging messages.

[0224] Optionally, the PF and PO for paging are determined in the following manner.

[0225] The system frame number of the PF (expressed as (SFN+PF_offset) mod T) is determined as follows. (SFN+PF_offset)mod T=(T div N)*(Terminal Device_ID mod N)

[0226] The index of a PO (denoted as i_s) is determined as follows. i_s=floor(terminal_device_ID / N)mod Ns

[0227] Each parameter is defined as follows: T: DRX cycle of the terminal device. N: Number of PFs in a paging cycle. PF_offset:PF offset. UE_ID:5G-S-TMSI mod 1024.

[0228] For example, Figure 2a is a diagram of a basic paging procedure. The overall procedure for initiating paging by the core network is as follows:

[0229] 1. A core network element (e.g., AMF) sends an NGAP paging message to an access network element (e.g., gNB), where the NGAP paging message carries a paging record list of the terminal device, and the paging record list including a 5G-s-Temporary mobile subscription identifier (5G-s-TMSI) is sent to the network device.

[0230] 2. After receiving the NGAP paging message, the access network element can calculate a specific PF and PO location based on the paging parameters and 5G-S-TMSI.

[0231] 3. The terminal device calculates the specific PF and PO location for paging based on the terminal device identifier 5G-S-TMSI, and uses the current paging-radio network temporary identifier (P-RNTI) to descramble and decode the paging physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH (paging message)).

[0232] In paging processing, when multiple terminal devices are monitoring the same paging occasion (PO), if paging is performed on only some of the terminal devices among the multiple terminal devices, the terminal devices that are not paged will receive unnecessary paging and will consume unnecessary power. This case is called a paging false alarm.

[0233] From the above-mentioned implementation example of the paging process, it can be seen that one of the main reasons for generating false paging alarms is that multiple terminal devices monitor the same PO. According to the calculation formula specified in the protocol, the 5G-S-TMSIs assigned to one core network may be different, but the UE_ID (i.e., 5G-S-TMSI mod 1024) may be the same. From the above-mentioned method for determining the PF and PO, it can be seen that the PO positions calculated by different terminal devices may be the same. In addition, in the paging mechanism, the terminal device obtains scheduling information for the paging message when receiving paging downlink control information (DCI), but cannot know whether the current paging message is a paging message for the terminal device. In this case, the terminal device can only determine whether the current paging is intended for the terminal device after subsequently receiving and decoding the paging message on the PDSCH based on the terminal device identifier information in the paging message. Therefore, when multiple terminal devices monitor the same PO, if paging is performed for only some terminal devices, unnecessary paging reception will occur for terminal devices that are not actually paged, resulting in unnecessary power consumption of the terminal devices.

[0234] Currently, a mechanism for grouping terminal devices is one of the techniques for reducing paging false alarms. The basic concept of this technique is to group terminal devices monitoring the same PO (i.e., divide terminal devices on the same PO into different groups). When a network device performs paging, the PEI indicates the number of the PO for which the current paging is performed, and indicates that the terminal devices are divided into different terminal device subgroups in each PO. In this way, before receiving a paging PDCCH and paging PDSCH (paging message), the terminal device knows whether it needs to receive a paging this time. This reduces the probability that the terminal device unnecessarily receives and decodes a paging message, and further reduces the power consumption generated when the terminal device decodes a paging PDCCH and paging PDSCH (paging message) that is not intended for the terminal device.

[0235] Optionally, the PEI indicates the terminal devices using a PDCCH in format (DCI2-7). The PEI can indicate whether subgroups of terminal devices in several subsequent POs and each PO need to monitor the paging PDCCH and paging PDSCH (paging message). An implementation example is shown in FIG. 2b. Terminal device 1 (denoted as UE1 in the figure) and terminal device 4 (denoted as UE4 in the figure) are terminal device subgroup 1 in the first PO. The first subgroup in the M subgroups to which the first PO belongs is indicated by the PEI as "1," indicating that terminal device 1 and terminal device 4 need to monitor the PDCCH at the location of the first PO and decode the PDSCH (paging message) based on the scheduling information indicated by the paging DCI after the paging DCI is decoded. Terminal device 2 (denoted as UE2 in the figure) and terminal device 3 (denoted as UE3 in the figure) are terminal device subgroup 2 in the first PO. The first subgroup among the M subgroups to which the first PO belongs is indicated by the PEI as "0", indicating that terminal device 2 and terminal device 3 do not need to monitor the PDCCH at the location of the first PO.

[0236] In addition, indication information (for example, the indication information may be a lastUsedCellOnly-r17 information element in the pei-Config-r17 information element) is added to the SIB1 sent by the network device. If the indication information exists, the terminal device needs to determine whether to monitor the PEI based on whether the current cell is the last used cell of the terminal device. However, for the terminal device, how to determine the last used cell of the terminal device is an urgent technical problem to be solved.

[0237] In a possible implementation, the terminal device can determine its last used cell based on the status of the RRC release message. Specifically, the cell via the RRCRelease message most recently received by the terminal device, which does not include the noLastCellUpdate-r17 information element, is the terminal device's last used cell. That is, the noLastCellUpdate-r17 information element is added to the RRCRelease message. If the noLastCellUpdate-r17 information element is present, the last used cell used for the PEI is not updated. Otherwise, the last used cell is updated to the current cell. However, for a terminal device, an incorrect update process may occur in the process of determining the last used cell based on this implementation. Below, a description is provided with reference to the implementation examples of Figure 3a (hereinafter referred to as Scenario 1) and Figure 3b (hereinafter referred to as Scenario 2).

[0238] Consider scenario 1 shown in Figure 3a. A terminal device supporting PEI capability first camps on cell A and then establishes a connection. After the terminal device receives an RRCRelease message from cell A and receives SIB1 broadcasted by cell A, if the PEI configuration includes the lastUsedCellOnly-r17 information element and the noLastCellUpdate-r17 information element is not present in the RRCRelease message from cell A, the terminal device stores the last used cell as cell A.

[0239] In this case, if there is a cell B nearby (for example, the cell B may be located in one or more cells corresponding to the fake base station), the downlink power is higher and the signal received by the terminal device from the cell B is better, so the terminal device can camp on the cell B in a reselection / redirection manner and then initiate link establishment in the cell B. After the link establishment is successful, non-access stratum (NAS) and access stratum (AS) authentication is performed. After the authentication fails, the cell B delivers an RRCRelease message over the air interface.

[0240] Scenario 2 shown in Figure 3b is considered. Similar to the implementation process of Scenario 1, a terminal device supporting PEI capability first camps on cell A of the NR network device and then establishes a connection. The terminal device receives an RRCRelease message over the air interface from the gNB and receives SIB1 broadcast by cell A. If the PEI configuration includes the lastUsedCellOnly-r17 information element and the noLastCellUpdate-r17 information element is not present in the RRCRelease message over the air interface, the terminal device stores the last used cell as cell A.

[0241] In this case, if there is a common cell B nearby (e.g., cell B may be located in one or more cells corresponding to a normally operating base station (i.e., the base station is not a fake base station)), the terminal device can camp on cell B in a reselection / redirection manner and then initiate link establishment with cell B. Because the access network element is temporarily overloaded or because the access network element temporarily discovers that the core network element is overloaded, the connection between the access network element and the core network element cannot be established and AS security cannot be activated. In this case, cell B broadcasts an RRCRelease message over the air interface to release the terminal device and uses noLastCellUpdate to indicate to the terminal device that it will not update the last used cell.

[0242] For Scenario 1 shown in Figure 3a: In one aspect, since the terminal device receives the RRCRelease message via the air interface on cell B of the fake base station, if AS security is not activated, the terminal device ignores the content carried in the RRCRelease message except for the waitTime parameter according to the protocol / standard. Regardless of whether the RRCRelease message via the air interface carries the noLastCellUpdate-r17 information element, the last used cell is incorrectly updated to cell B. Therefore, in the subsequent process of reselecting cell A from cell B, the last used cell is cell B, not cell A, and therefore the PEI function cannot be used normally.

[0243] For scenario 2 shown in Figure 3b: When the terminal device receives the RRCRelease message via the air interface on cell B, if AS security is not activated, the terminal device ignores the contents of the RRCRelease message except for the waitTime parameter, as specified in the protocol / standard. Although the RRCRelease message via the air interface carries the noLastCellUpdate-r17 information element, the last used cell is incorrectly updated to cell B according to the protocol. Therefore, in the subsequent reselection process from cell B to cell A, the PEI function cannot be used normally because the last used cell is cell B, not cell A.

[0244] From the above, it can be seen that how to determine the last used cell of a terminal device is an urgent technical problem to be solved. In addition, the implementation used in the implementation examples shown in Figures 3a and 3b easily causes a problem that the PEI function cannot be used normally. In view of this, to solve the above problem, the present application provides a communication method and a communication device for avoiding paging errors caused by unauthorized updates of the terminal device, enhancing the PEI function implemented by the terminal device based on first information, and reducing the power consumption of the terminal device. The following provides further explanation with reference to the accompanying drawings.

[0245] FIG. 4 is a diagram of an implementation of the communication method according to the present application.

[0246] S401: A network device transmits a first message.

[0247] In this embodiment, the network device sends a first message in step S401, and correspondingly, the terminal device receives the first message in step S401. The first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device.

[0248] In the present application, the message name of the first message indicating the release of the RRC connection between the terminal device and the network device may be an RRC Release (RRCReleace) message, and the name is the name in the current communication system. In the future communication system, the name of the message indicating the release of the RRC connection between the terminal device and the network device may change with the evolution of the communication system.

[0249] S402: The terminal device determines not to update the first information.

[0250] In this embodiment, if access stratum (AS) security between the terminal device and the network device is not activated, the terminal device determines not to update the first information in step S402. The first information indicates the last used cell of the terminal device.

[0251] It should be understood that the last used cell of the terminal device indicated by the first information may be referred to as the most recently accessed cell of the terminal device, the cell most recently accessed by the terminal device, the cell from which the connection of the terminal device was released, the cell from which the first message was sent to the terminal device, the cell last served by the terminal device, etc.

[0252] It should be noted that in step S402, the terminal device deciding not to update the first information may be expressed as the terminal device not updating the first information, or as the terminal device deciding not to update the first information without identifying whether the first message carries instruction information indicating to update (or not update) the first information, or as the terminal device not performing an update of the first information, or as the terminal device maintaining the first information without changing it, or as the first information maintained by the terminal device remaining unchanged.

[0253] In a possible implementation form, the first information that the terminal device decides not to update in step S402 includes information about the last used cell of the terminal device.

[0254] Optionally, the first information may include an identifier of a last-use cell of the terminal device. For example, the identifier may be a cell global identifier (CGI) or a physical cell identifier (PCI).

[0255] In one implementation example, the last-used cell indicated by the first information maintained by the terminal device before step S401 is cell 1. Then, the terminal device receives a first message from cell 2 in step S401 (cell 2 is located in one or more cells corresponding to the network device that sent the first message in step S401). In step S402, the terminal device determines not to update the first information, specifically, the terminal device determines in step S402 that there is no need to update the maintained first information, and maintains the last-used cell indicated by the first information as cell 1.

[0256] In another implementation example, the last-used cell indicated by the first information maintained by the terminal device before step S401 is empty (i.e., the terminal device does not maintain the first information of the terminal device). Then, the terminal device receives a first message from cell 2 in step S401 (cell 2 is located in one or more cells corresponding to the network device that sent the first message in step S401). In step S402, the terminal device determines not to update the first information, specifically, in step S402, the terminal device determines that the maintained first information does not need to be updated, and still maintains that the last-used cell indicated by the first information is empty (i.e., cell 2 is not maintained as the last-used cell indicated by the first information).

[0257] In a possible implementation, after the network device sends the first message in step S401, if access stratum security between the terminal device and the network device is not activated, the network device determines (after step S401, for example, in step S402) that the terminal device will not update the first information, and the first information indicates the last used cell of the terminal device. Specifically, if access stratum security between the terminal device and the network device is not activated, the network device may determine that the network device cannot communicate with the terminal device based on the access stratum security mechanism. In consideration of this, the network device determines that the terminal device will not update the first information, so that the network device and the terminal device have aligned and harmonized understandings of the first information, reducing the possibility of communication errors.

[0258] In a possible implementation, the first message received by the terminal device in step S401 includes first indication information, and the first indication information indicates not to update the first information. Correspondingly, in step S402, if access stratum security between the terminal device and the network device is not activated, the terminal device ignores the first indication information. Specifically, if access stratum security between the terminal device and the network device is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, the terminal device may ignore the first indication information carried in the first message and determine not to update the first information. In other words, to avoid paging errors caused by unauthorized updates of the terminal device, the terminal device may determine not to update the first information without identifying whether the first message carries indication information indicating to update (or not update) the first information.

[0259] It should be understood that in the present application, the name of the first indication information may be a noLastCellUpdate information element / field / domain / parameter. The name is the name in the current communication system. In the future communication system, the name of the first indication information may change with the evolution of the communication system.

[0260] In a possible implementation, the first message received by the terminal device in step S401 includes second instruction information, which indicates a wait time for accessing the network. Correspondingly, in step S402, the terminal device ignores at least one piece of information in the first message except for the second instruction information, and the at least one piece of information includes first instruction information, which indicates not to update the first information. Specifically, the first message received by the terminal device may include second instruction information indicating a wait time for accessing the network, so that the terminal device can subsequently re-establish a connection to the network device based on the second instruction information. In addition, if access stratum security between the terminal device and the network device is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, the terminal device may ignore at least one piece of information in the first message except for the second instruction information.

[0261] Optionally, the terminal device ignoring at least one piece of information in the first message except for the second instruction information may include the terminal device ignoring information in the first message except for the second instruction information.

[0262] Optionally, the second indication information may alternatively be expressed in other ways, including: the second indication information indicating the time duration of timer T302 (T302 indicating the waiting time for the terminal device to re-establish or resume the RRC connection); the second indication information indicating the waiting time for an access attempt of the terminal device; the second indication information indicating the waiting time for controlling the terminal device to establish the RRC connection.

[0263] It should be understood that in this application, the name of the second indication information may be a waitTime information element / field / domain / parameter. The name is the name in the current communication system. In future communication systems, the name of the second indication information may change with the evolution of the communication system.

[0264] Optionally, after step S401, if access stratum security between the terminal device and the network device is not activated, the network device determines that the terminal device will ignore at least one piece of information in the first message except for the second instruction information, where the at least one piece of information includes first instruction information, the first instruction information indicating not to update the first information, and the first information indicating a last-used cell of the terminal device. Specifically, the first message sent by the network device in step S401 may include second instruction information indicating a waiting time for accessing the network, so that the terminal device can subsequently re-establish a connection to the network device based on the second instruction information. In addition, if access stratum security between the terminal device and the network device is not activated, the network device may determine that the network device cannot communicate with the terminal device based on the access stratum security mechanism. In consideration of this, the network device may determine that the terminal device will ignore at least one piece of information in the first message except for the second instruction information, so that the network device and the terminal device are aligned in their understanding of the first message and reduce the possibility of communication errors.

[0265] In a possible implementation form, if any one of the following is satisfied, the terminal device determining in step S402 that access stratum security between the terminal device and the network device is not activated includes: the terminal device determining that a security mode command message is not received; and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed; or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed. Specifically, in order to increase the flexibility of implementing the solution, the terminal device can determine that access stratum security between the terminal device and the network device is not activated in the above-mentioned multiple manners.

[0266] In a possible implementation, before step S401, the method further includes a step in which the terminal device transmits first capability information, where the first capability information indicates that the terminal device supports the PEI. Specifically, the terminal device can transmit the first capability information indicating that the terminal device supports the PEI to the network device, so that the network device determines that the terminal device supports the PEI based on the first capability information and communicates with the terminal device based on the PEI mechanism.

[0267] 4 (before or after any step), the method further includes a step in which the terminal device receives third indication information, where the third indication information indicates that the network device supports the PEI. Specifically, the network device can send third indication information indicating that the network device supports the PEI to the terminal device, so that the terminal device determines that the network device supports the PEI based on the third indication information and communicates with the network device based on the PEI mechanism.

[0268] Optionally, in addition to the above-mentioned implementation of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another implementation. For example, in one implementation of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0269] The above describes an implementation process that may be performed by the terminal device in step S402 when access stratum security between the terminal device and the network device is not activated. The following describes an example of an implementation process that may be performed by the network device in this case.

[0270] In a possible implementation, when the network device sends the first message sent in step S401 and it is determined that access stratum security between the terminal device and the network device is not activated, in step S403, the network device determines not to update the second information, and the second information indicates one or more cells accessed by the terminal device.

[0271] Specifically, the network device may maintain second information indicating one or more cells accessed by the terminal device. In a scenario in which the network device transmits a first message indicating the release of the RRC connection between the terminal device and the network device to release the RRC connection, if access stratum security between the terminal device and the network device is not activated, the network device may determine not to update the second information. If access stratum security is not activated, the network device may determine, based on the access stratum security mechanism, that the network device cannot communicate with the terminal device. Therefore, in a manner in which the network device determines not to update the second information, the network device does not update the second information based on the cell from which the first message was transmitted (in this case, the cell is located in one or more cells corresponding to the network device), thereby avoiding paging errors caused by unauthorized updates of the network device, enhancing the PEI function implemented by the network device based on the second information, and reducing the power consumption of the network device.

[0272] Optionally, the network device determining not to update the second information may be expressed as the network device not updating the second information, or the network device determining not to update the second information without identifying whether the first message carries instruction information indicating to update (or not update) the first information, or the network device not performing an update of the second information, or the network device keeping the second information unchanged, or the second information maintained by the network device remaining unchanged.

[0273] Optionally, after step S401, if access stratum security between the terminal device and the network device is not activated, in step S403, the network device determines that the terminal device will ignore the first indication information. Specifically, if access stratum security between the terminal device and the network device is not activated, the network device may determine that the network device cannot communicate with the terminal device based on the access stratum security mechanism. In consideration of this, the network device determines that the terminal device will ignore the first indication information, so that the network device and the terminal device are aligned in their understanding of the first information, reducing the possibility of communication errors.

[0274] In a possible implementation, the network device transmits the second information to the core network device. Specifically, the network device can further transmit the second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0275] S404: Release the RRC connection between the terminal device and the network device.

[0276] In this embodiment, after the network device sends the first message in step S401, the network device releases the RRC connection to the terminal device in step S404. After the terminal device receives the first message in step S401, the terminal device releases the RRC connection to the network device in step S404.

[0277] It should be noted that both step S402 and step S404 are executed after step S401. However, the execution order of step S402 and step S404 is not limited in this embodiment. For example, step S402 may be executed after step S404, or step S404 may be executed after step S402.

[0278] Similarly, when the network device executes step S403, both step S403 and step S404 are executed after step S401. However, the execution order of step S403 and step S404 is not limited in this embodiment. For example, step S403 may be executed after step S404, and step S404 may be executed after step S403.

[0279] It should be understood that in step S404, the terminal device releasing the RRC connection may be understood as the terminal device exiting the RRC connected mode and the terminal device entering a state other than the RRC connected mode, for example, an idle state or an inactive state.

[0280] Optionally, if access stratum security between the terminal device and the network device is not activated, the terminal device may enter an idle state.

[0281] Based on the technical solution shown in FIG. 4, a terminal device can maintain first information indicating a last-used cell of the terminal device. In a scenario in which the terminal device receives a first message indicating the release of the RRC connection between the terminal device and the network device in step S401 and releases the RRC connection in step S404, if access stratum security between the terminal device and the network device is not activated, the terminal device determines not to update the first information in step S402. If access stratum security is not activated, the terminal device can determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in the manner in which the terminal device determines not to update the first information, the terminal device does not update the first information based on the cell to which the first message was transmitted (the cell is located in one or more cells corresponding to the network device), thereby avoiding paging errors caused by unauthorized updating of the terminal device, enhancing the PEI function implemented by the terminal device based on the first information, and reducing the power consumption of the terminal device.

[0282] It can be seen from the embodiment shown in FIG. 4 that if access stratum security between the terminal device and the network device is not activated, the terminal device determines in step S402 not to update the first information (or the network device determines in step S403 that the terminal device does not update the first information). In this way, the terminal device (or the network device) can ignore the related instruction information (e.g., the above-mentioned first instruction information) in the first message indicating that the first information should be updated (or not updated). In other words, in the embodiment shown in FIG. 4, the terminal device (or the network device) can determine by default that the terminal device does not update the first information without reading the related instruction information in the first message indicating that the first information should be updated (or not updated). As a result, paging errors caused by unauthorized updates of the terminal device can be avoided, the PEI function implemented by the terminal device based on the first information can be enhanced, and the power consumption of the terminal device can be reduced, thereby solving the aforementioned technical problem of "a method for determining a last-used cell of a terminal device." Hereinafter, another embodiment provided in the present application to solve the technical problem will be described with reference to the embodiments shown in FIGS. 5 and 6.

[0283]

[0033] It should be noted that, unlike the implementation form of the embodiment shown in Figure 4, in which the terminal device (or network device) determines by default not to update the first information without reading the related instruction information in the first message indicating to update (or not update) the first information, in the following embodiments shown in Figures 5 and 6, the terminal device (or network device) needs to read the related instruction information in the first message indicating to update (or not update) the first information, and perform corresponding operations based on the related instruction information. Detailed descriptions are provided below with reference to the accompanying drawings.

[0284] FIG. 5 is a diagram of an implementation of the communication method according to the present application.

[0285] It should be noted that the implementation process of step S501 and step S504 in Figure 5 can be referred to the implementation process of step S401 and step S404 in Figure 4, and the corresponding technical effects can be achieved, which will not be described in detail below.

[0286] S501: A network device transmits a first message.

[0287] In this embodiment, in step S501, the network device sends a first message, and correspondingly, in step S501, the terminal device receives a first message, which indicates releasing a radio resource control (RRC) connection between the terminal device and the network device.

[0288] S502: The terminal device determines not to ignore the first instruction information in the first message, or the terminal device ignores at least one piece of information in the first message other than the first instruction information and the second instruction information.

[0289] In this embodiment, if access stratum (AS) security between the terminal device and the network device is not activated, in step S502, the terminal device determines not to ignore the first indication information in the first message, or the terminal device ignores at least one piece of information in the first message except the first indication information and the second indication information, where the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network.

[0290] In a possible implementation, for a network device, after the first message is sent in step S501, if access stratum security between the terminal device and the network device is not activated, the network device determines (after step S501, for example, in step S502) that the terminal device will not ignore the first indication information in the first message, or the network device determines (after step S501, for example, in step S502) that the terminal device will ignore at least one piece of information in the first message excluding the first indication information and the second indication information. Specifically, if access stratum security between the terminal device and the network device is not activated, the network device may determine that the network device cannot communicate with the terminal device based on the access stratum security mechanism. In consideration of this, the network device determines that the terminal device will not ignore the first indication information in the first message (or the network device determines that the terminal device will ignore at least one piece of information in the first message excluding the first indication information and the second indication information), so that the network device and the terminal device are aligned in their understanding of the first information, reducing the possibility of communication errors.

[0291] Optionally, the terminal device ignoring at least one information in the first message other than the first instruction information and the second instruction information may include the terminal device ignoring other information in the first message other than the first instruction information and the second instruction information.

[0292] In a possible implementation, the method further includes a step in which the terminal device determines not to update the first information based on the first indication information. Specifically, the process in which the terminal device determines not to ignore the first indication information may include the terminal device determining not to update the first information based on the first indication information, and as a result, the terminal device determining not to update the first information based on the first indication information sent by the network device. In this way, the terminal device and the network device are aligned in their understanding of the first indication information, reducing the possibility of communication errors.

[0293] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0294] Optionally, the first information may include an identifier of a final use cell of the terminal device. For example, the identifier may be a CGI, a PCI, etc.

[0295] In a possible implementation form, if any one of the following is satisfied, the terminal device determining in step S502 that access stratum security between the terminal device and the network device is not activated includes: the terminal device determining that a security mode command message is not received; and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed; or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed. Specifically, in order to increase the flexibility of implementing the solution, the terminal device can determine that access stratum security between the terminal device and the network device is not activated in the above-mentioned multiple manners.

[0296] The above describes an implementation process that may be performed by the terminal device in step S502 when access stratum security between the terminal device and the network device is not activated. The following describes an example of an implementation process that may be performed by the network device in this case.

[0297] In a possible implementation, if access stratum security between the terminal device and the network device is not activated, in step S503, the network device decides not to ignore the first indication information in the first message, or the network device decides to ignore at least one piece of information in the first message excluding the first indication information and the second indication information.

[0298] Specifically, if access stratum security is not activated, the network device may determine, based on the access stratum security mechanism, that the network device cannot communicate with the terminal device. Therefore, in a manner in which the network device determines not to ignore the first indication information in the first message (or the network device ignores at least one piece of information in the first message other than the first indication information and the second indication information), the network device determines that the terminal device will not update the first information based on the cell through which the first message is transmitted (in this case, the cell is located in one or more cells corresponding to the network device), thereby enhancing the PEI function implemented by the terminal device based on the first information and reducing the power consumption of the terminal device, thereby avoiding paging errors caused by unauthorized updates of the terminal device.

[0299] Additionally, in a manner in which the network device decides not to ignore the first instruction information in the first message (or the network device ignores at least one piece of information in the first message other than the first instruction information and the second instruction information), the terminal device and the network device are aligned in their understanding of the first instruction information, which can reduce the possibility of communication errors.

[0300] Optionally, the network device ignoring at least one information in the first message except for the first instruction information and the second instruction information may include the network device ignoring information in the first message except for the first instruction information and the second instruction information.

[0301] In a possible implementation, in the aforementioned implementation, the method further includes a step of the network device determining, based on the first indication information, not to update the second information, where the second information indicates one or more cells accessed by the terminal device. Specifically, the network device can determine, based on the first indication information, not to update the second information indicating one or more cells accessed by the terminal device, so that the terminal device and the network device are aligned in their understanding of the first indication information, reducing the possibility of communication errors.

[0302] In a possible implementation, the second information includes an identifier of one or more cells accessed by the terminal device. Optionally, the identifier of the one or more cells accessed by the terminal device may be a CGI, a PCI, etc.

[0303] In a possible implementation, in the aforementioned implementation, the method further includes a step in which the network device transmits second information to the core network device. Specifically, the network device can further transmit second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0304] In a possible implementation, before step S501, the method further includes a step in which the terminal device transmits first capability information, where the first capability information indicates that the terminal device supports a paging early notification PEI. Specifically, the terminal device can transmit the first capability information indicating that the terminal device supports a PEI to the network device, so that the network device determines that the terminal device supports a PEI based on the first capability information and communicates with the terminal device based on a PEI mechanism.

[0305] 5 (before or after any step), the method further includes a step in which the terminal device receives third indication information, where the third indication information indicates that the network device supports the PEI. Specifically, the network device can send the third indication information indicating that the network device supports the PEI to the terminal device, so that the terminal device determines that the network device supports the PEI based on the third indication information and communicates with the network device based on the PEI mechanism.

[0306] Optionally, in addition to the above-mentioned implementation of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another implementation. For example, in one implementation of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0307] S504: Release the RRC connection between the terminal device and the network device.

[0308] In this embodiment, after the network device sends a first message in step S501, the network device releases the RRC connection with the terminal device in step S504. After the terminal device receives the first message in step S501, the terminal device releases the RRC connection to the network device in step S504.

[0309] It should be noted that step S502 and step S504 are both executed after step S501. However, the execution order of step S502 and step S504 is not limited in this embodiment. For example, step S502 may be executed after step S504, or step S504 may be executed after step S502.

[0310] Similarly, when the network device executes step S503, both step S503 and step S504 are executed after step S501. However, the execution order of step S503 and step S504 is not limited in this embodiment. For example, step S503 may be executed after step S504, and step S504 may be executed after step S503.

[0311] 5, the terminal device may maintain first information indicating a last-used cell of the terminal device. In a scenario in which the terminal device receives a first message indicating release of an RRC connection between the terminal device and a network device in step S501 and releases the RRC connection in step S504, if access stratum security between the terminal device and the network device is not activated, the terminal device may determine not to ignore the first indication information in the first message in step S502, or may ignore at least one piece of information in the first message excluding the first indication information and the second indication information. If access stratum security is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in a manner in which the terminal device decides not to ignore the first instruction information in the first message (or the terminal device ignores at least one piece of information in the first message excluding the first instruction information and the second instruction information), the terminal device does not update the first information based on the cell (in this case, the cell is located in one or more cells corresponding to the network device) from which the first message is transmitted, so that paging errors caused by unauthorized updates of the terminal device can be avoided, the PEI function implemented by the terminal device based on the first information is enhanced, and the power consumption of the terminal device is reduced.

[0312] Additionally, in a manner in which the terminal device determines in step S502 not to ignore the first instruction information in the first message (or the terminal device ignores at least one piece of information in the first message other than the first instruction information and the second instruction information), the terminal device and the network device are aligned in their understanding of the first instruction information, reducing the possibility of communication errors.

[0313] FIG. 6 is a diagram of an implementation of the communication method according to the present application.

[0314] It should be noted that the implementation process of step S601 and step S604 in Figure 6 can be referred to the implementation process of step S401 and step S404 in Figure 4, and the corresponding technical effects can be achieved, which will not be described in detail below.

[0315] S601: A network device sends a first message.

[0316] In this embodiment, in step S601, the network device sends a first message, and correspondingly, in step S601, the terminal device receives a first message, which indicates releasing a radio resource control (RRC) connection between the terminal device and the network device.

[0317] S602: The terminal device processes first information based on the first message.

[0318] In this embodiment, if access stratum (AS) security between the terminal device and the network device is not activated, in step S602, the terminal device processes first information based on the first message, where the first information indicates a last-used cell of the terminal device.

[0319] In a possible implementation, in step S602, the terminal device processes the first information based on the first message includes: if the first message includes first instruction information, the terminal device determines not to update the first information, where the first instruction information indicates not to update the first information. Specifically, if the first message includes first instruction information indicating not to update the first information, the terminal device determines not to update the first information, so that the terminal device performs a corresponding operation based on the instruction of the network device to reduce the possibility of communication errors.

[0320] In a possible implementation, in step S602, the terminal device processes the first information based on the first message includes: if the first message does not include first instruction information, the terminal device updates the first information based on a cell corresponding to the first message, and the first instruction information indicates not to update the first information. Specifically, if the first message does not include the first instruction information, the terminal device updates the first information based on a cell corresponding to the first message, so that the terminal device performs a corresponding operation based on an instruction from the network device to reduce the possibility of communication errors.

[0321] It should be understood that the process in which the terminal device updates the first information based on the cell corresponding to the first message includes the terminal device updating the first information based on the cell identifier of the cell from which the first message is transmitted, or the terminal device updating the first information based on the cell identifier carried in the first message. This is not limited herein. For example, in the above-mentioned embodiment, the terminal device updates the first information based on the cell identifier of the cell from which the first message is transmitted. In other words, the terminal device updates information about the last-used cell indicated by the first information as the cell identifier of the cell from which the first message is transmitted.

[0322] In a possible implementation, the first information includes information about a last-used cell of the terminal device. Optionally, the first information may include an identifier of the last-used cell of the terminal device. For example, the identifier may be CGI, PCI, etc.

[0323] In a possible implementation form, if any one of the following is satisfied, the terminal device determining in step S602 that access stratum security between the terminal device and the network device is not activated includes: the terminal device determining that a security mode command message is not received; and after the terminal device receives the security mode command message, the terminal device determining that a process of deriving a key based on the security mode command message has failed; or after the terminal device receives the security mode command message, the terminal device determining that integrity protection verification corresponding to the security mode command message has failed. Specifically, in order to increase the flexibility of implementing the solution, the terminal device can determine that access stratum security between the terminal device and the network device is not activated in the above-mentioned multiple manners.

[0324] The above describes an implementation process that may be performed by the terminal device in step S602 if access stratum security between the terminal device and the network device is not activated. The following describes an example of an implementation process that may be performed by the network device in this case.

[0325] In a possible implementation, after the network device sends the first message in step S601, the network device determines whether the terminal device updates the first information based on the first message. Specifically, the network device can further determine whether the terminal device updates the first information based on the first message, so that the network device determines the behavior of the terminal device to avoid communication errors.

[0326] In a possible implementation, in step S601, if the network device sends a first message and access stratum security between the terminal device and the network device is not activated, in step S603, the network device processes second information based on the first message, and the second information indicates one or more cells accessed by the terminal device.

[0327] Specifically, the network device may maintain second information indicating one or more cells accessed by the terminal device. In a scenario in which the network device releases the RRC connection by transmitting a first message indicating release of the RRC connection between the terminal device and the network device, the network device processes the second information based on the first message. If access stratum security is not activated, the network device may determine, based on the access stratum security mechanism, that the terminal device cannot communicate with the network device. Therefore, in a manner in which the network device processes the first information based on the first message, the terminal device and the network device are aligned in their understanding of the first message, reducing the possibility of communication errors.

[0328] Optionally, similar to the implementation process of the terminal device in step S602, the network device processing the second information based on the first message includes: if the first message includes first instruction information, the network device determines not to update the second information, where the first instruction information indicates not to update the first information, and the first information indicates information about the last used cell of the terminal device. Specifically, if the first message includes first instruction information indicating not to update the first information, the network device determines not to update the second information, so that the terminal device continues to perform a corresponding operation based on the instruction of the network device, thereby reducing the possibility of communication errors.

[0329] Optionally, similar to the implementation process of the terminal device in step S602, the terminal device's processing of the first information based on the first message includes: if the first message does not include first instruction information, the terminal device updates the second information based on a cell corresponding to the first message, where the first instruction information indicates not to update the first information, and the first information indicates information about the last-used cell of the terminal device. Specifically, if the first message does not include the first instruction information, the network device updates the second information based on the cell corresponding to the first message, so that the terminal device then performs a corresponding operation based on the instruction of the network device to reduce the possibility of communication errors.

[0330] It should be understood that the process of the network device updating the second information based on the cell corresponding to the first message includes: the network device updating the second information based on a cell identifier of the cell to which the first message is transmitted; or the network device updating the second information based on a cell identifier carried in the first message, which is not limited herein.

[0331] In a possible implementation, the method further includes the step of the network device transmitting second information to the core network device. Specifically, the network device can further transmit the second information indicating one or more cells accessed by the terminal device to the core network device, so that the core network device and the network device are aligned in their understanding of the second information, reducing the possibility of communication errors.

[0332] In a possible implementation, before step S601, the method further includes a step in which the terminal device transmits first capability information, where the first capability information indicates that the terminal device supports the PEI. Specifically, the terminal device can transmit the first capability information indicating that the terminal device supports the PEI to the network device, so that the network device determines that the terminal device supports the PEI based on the first capability information and communicates with the terminal device based on the PEI mechanism.

[0333] 6 (before or after any step), the method further includes a step in which the terminal device receives third indication information, where the third indication information indicates that the network device supports the PEI. Specifically, the network device can send third indication information indicating that the network device supports the PEI to the terminal device, so that the terminal device determines that the network device supports the PEI based on the third indication information and communicates with the network device based on the PEI mechanism.

[0334] Optionally, in addition to the above-mentioned implementation of the interaction between the first capability information and the third instruction information, the terminal device and the network device can further learn each other's capability information in another implementation. For example, in one implementation of the interaction between the terminal device and another device, the other device may be a core network device, a sidelink device, a server, etc. In another example, the implementation is pre-configured using a protocol / standard.

[0335] S604: Release the RRC connection between the terminal device and the network device.

[0336] In this embodiment, after the network device sends a first message in step S601, the network device releases the RRC connection to the terminal device in step S604. After the terminal device receives the first message in step S601, the terminal device releases the RRC connection to the network device in step S604.

[0337] It should be noted that step S602 and step S604 are both executed after step S601. However, the execution order of step S602 and step S604 is not limited in this embodiment. For example, step S602 may be executed after step S604, and step S604 may be executed after step S602.

[0338] Similarly, when the network device executes step S603, both step S603 and step S604 are executed after step S601. However, the execution order of step S603 and step S604 is not limited in this embodiment. For example, step S603 may be executed after step S604, and step S604 may be executed after step S603.

[0339] Based on the technical solution shown in FIG. 6, a terminal device can maintain first information indicating a last-used cell of the terminal device. In a scenario in which the terminal device receives a first message indicating release of an RRC connection between the terminal device and a network device in step S601 and releases the RRC connection in step S604, the terminal device processes the first information based on the first message in step S602. If access stratum security is not activated, the terminal device may determine that the terminal device cannot communicate with the network device based on the access stratum security mechanism. Therefore, in the method in which the terminal device processes the first information based on the first message, the terminal device and the network device are aligned in their understanding of the first message, reducing the possibility of communication errors.

[0340] In the implementation shown in FIG. 4, if AS security is not activated, it can be seen from the implementation processes shown in FIGS. 4 to 6 that the terminal device ignores the first indication information in the first message and does not update the first information. In this way, the first information is not updated to an inappropriate cell, thereby enhancing the PEI function of the UE and reducing energy consumption. In the implementation examples shown in FIGS. 5 and 6, if AS security is not activated, the first indication information in the first message is not ignored, and it is still determined not to update the first information based on the first indication information in the first message. In this way, the first information is not updated to an inappropriate cell, thereby enhancing the PEI function of the terminal device and reducing energy consumption.

[0341] In the following, an example will be used to describe the embodiment shown in FIG. 4 with respect to the implementation process shown in FIG. 7 , and an example will be used to describe the implementation forms shown in FIGS. 5 and 6 with respect to the implementation process shown in FIG. 8 .

[0342] 7 and 8, it should be understood that the first message is an RRCRelease message, and the first indication information in the first message is a noLastCellUpdate information element / field / domain / parameter. An example in which the first information is a last used cell information element / field / field / parameter is used for explanation.

[0343] As shown in FIG. 7, in the implementation example of the implementation form shown in FIG. 4, the implementation example includes the following processes:

[0344] 1. When AS security is activated, a terminal device supporting the PEI function updates the last used cell based on noLastCellUpdate in the RRCRelease message over the air interface.

[0345] If noLastCellUpdate is not included, the terminal device updates the last used cell to the current cell.

[0346] If noLastCellUpdate is included, the terminal device does not update the last used cell.

[0347] 2. If AS security is not activated, the terminal device directly ignores the noLastCellUpdate information element and does not update the last used cell.

[0348] It can be seen from the embodiment shown in FIG. 7 that in Scenario 1 shown in FIG. 3a, after the terminal device receives an RRCRelease message from the fake base station via the air interface, AS security is not activated, so the last used cell can be prevented from being updated to the cell served by the fake base station. In Scenario 2 shown in FIG. 3b, in a scenario where an access network element or a core network element is temporarily overloaded, a connection cannot be established between the access network element or the core network element, so AS security is not activated. After the RRCRelease message via the air interface is received, the last used cell is prevented from being updated to the cell served by the overloaded base station. Therefore, the PEI function of the terminal device can be enhanced, and the power-saving performance of the terminal device can be ensured. In addition, if AS security is not activated, the terminal device directly ignores the noLastCellUpdate and does not update the last used cell. In this way, the last used cell is not updated to an inappropriate cell.

[0349] As shown in FIG. 8, in the implementation example of the implementation form shown in FIG. 5 and FIG. 6, the implementation example includes the following processes:

[0350] 1. When AS security is activated, a terminal device supporting the PEI function updates the last used cell based on noLastCellUpdate in the RRCRelease message over the air interface.

[0351] If noLastCellUpdate is not included, the terminal device updates the last used cell to the current cell.

[0352] If noLastCellUpdate is included, the terminal device does not update the last used cell.

[0353] 2. If AS security is not activated, the noLastCellUpdate information element in the RRCRelease message over the air interface is not ignored, and the last used cell is still updated based on the noLastCellUpdate information element.

[0354] If noLastCellUpdate is not included, the terminal device updates the last used cell to the current cell.

[0355] If noLastCellUpdate is included, the terminal device does not update the last used cell.

[0356] As can be seen from the embodiment of FIG. 8, in Scenario 2 shown in FIG. 3b, in a scenario where an access network element or a core network element is temporarily overloaded, a connection between the access network element or the core network element cannot be established, and therefore AS security is not activated. After an RRCRelease message is received over the air interface, the last used cell is prevented from being updated to a cell served by the overloaded base station. Therefore, the PEI function of the terminal device can be enhanced, and the power-saving performance of the terminal device can be ensured. In addition, when AS security is not activated, the terminal device does not ignore noLastCellUpdate and still updates the last used cell based on noLastCellUpdate. In this way, the last used cell is not updated to an inappropriate cell due to the gNB or the core network being temporarily overloaded.

[0357] The above describes the present application from the perspective of the method. In the following, the communication device provided in the present application will be described.

[0358] Please refer to Figure 9. An embodiment of the present application provides a communication device 900. The communication device 900 can implement the functions of the terminal device or the network device in the above-mentioned method embodiments, and thus can also achieve the beneficial effects of the above-mentioned method embodiments. In this embodiment of the present application, the communication device 900 may be a terminal device or a network device, or may be an integrated circuit, an element, etc. in a terminal device or a network device, for example, a chip. In the following embodiments, an example in which the communication device 900 is a terminal device or a network device is used for description.

[0359] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the terminal device in the above-described embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines not to update the first information, the first information indicates a last-used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit 901 releases the RRC connection.

[0360] In one possible implementation, the first message includes first indication information, and the first indication information indicates not to update the first information. If access stratum security between the terminal device and the network device is not activated, the processing unit 901 is further configured to ignore the first indication information.

[0361] In one possible implementation, the first message includes second instruction information, the second instruction information indicating a waiting time for accessing the network. The processing unit 901 is further configured to ignore at least one piece of information in the first message except for the second instruction information, the at least one piece of information including the first instruction information, the first instruction information indicating not to update the first information.

[0362] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0363] In a possible implementation, if any of the following is met, the processing unit 901 determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit 901 determining that a security mode command message is not received; and after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that integrity protection verification corresponding to the security mode command message has failed.

[0364] In a possible implementation, the transceiver unit 902 is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0365] In a possible implementation, the transceiver unit 902 is further configured to receive third indication information, where the third indication information indicates that the network device supports the PEI.

[0366] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the network device in the above embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 is transmitting a first message and access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines not to update second information, the second information indicating one or more cells accessed by the terminal device, and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit 901 releases the RRC connection.

[0367] In one embodiment, the first message includes first instruction information, the first instruction information indicates not to update the first information, and the first information indicates a last-used cell of the terminal device. If access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines that the terminal device ignores the first instruction information.

[0368] In a possible implementation, the first message includes second indication information, and the second indication information indicates a waiting time for accessing the network. If access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines that the terminal device ignores at least some information in the first message except for the second indication information, and the at least some information includes first indication information, and the first indication information indicates not to update the first information, and the first information indicates a last-used cell of the terminal device.

[0369] In a possible implementation, if access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines that the terminal device does not update the first information, and the first information indicates the last used cell of the terminal device.

[0370] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0371] In a possible implementation, the second information includes identifiers of one or more cells accessed by the terminal device.

[0372] In a possible implementation, the transceiver unit 902 is further configured to transmit the second information to the core network device.

[0373] In a possible implementation, the transceiver unit 902 is further configured to transmit third indication information, where the third indication information indicates that the network device supports the PEI.

[0374] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the terminal device in the aforementioned embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines not to ignore first indication information in the first message, or the processing unit 901 ignores at least one piece of information in the first message except for the first indication information and the second indication information, where the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The processing unit 901 releases the RRC connection.

[0375] In a possible implementation form, the processing unit 901 is further configured to determine, based on the first indication information, not to update the first information.

[0376] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0377] In a possible implementation, if any of the following is met, the processing unit 901 determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit 901 determining that a security mode command message is not received; and after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that integrity protection verification corresponding to the security mode command message has failed.

[0378] In a possible implementation, the transceiver unit 902 is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0379] In a possible implementation, the transceiver unit 902 is further configured to receive third indication information, where the third indication information indicates that the network device supports the PEI.

[0380] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the network device in the aforementioned embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 is transmitting a first message and access stratum security between the network device and the terminal device is not activated, the processing unit 901 determines not to ignore first indication information in the first message, or the processing unit 901 ignores at least one piece of information in the first message except for the first indication information and the second indication information, where the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The processing unit 901 releases the RRC connection.

[0381] In a possible implementation, the processing unit 901 is further configured to determine, based on the first indication information, not to update the second information, where the second information indicates one or more cells accessed by the terminal device.

[0382] In a possible implementation, the second information includes identifiers of one or more cells accessed by the terminal device.

[0383] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0384] In a possible implementation, if access stratum security between the terminal device and the network device is not activated, the processing unit 901 determines that the terminal device does not ignore the first indication information in the first message, or the processing unit 901 determines that the terminal device ignores at least one piece of information in the first message excluding the first indication information and the second indication information.

[0385] In a possible implementation, the transceiver unit 902 is further configured to transmit the second information to the core network device.

[0386] In a possible implementation, the transceiver unit 902 is further configured to receive first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0387] In a possible implementation, the transceiver unit 902 is further configured to transmit third indication information, where the third indication information indicates that the network device supports the PEI.

[0388] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the terminal device in the above-described embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 receives a first message and access stratum security between the terminal device and the network device is not activated, the processing unit 901 processes first information based on the first message, where the first information indicates information about a last-used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The processing unit 901 releases the RRC connection.

[0389] In a possible implementation, the processing unit 901 processing the first information based on the first message includes the processing unit 901 determining not to update the first information if the first message includes first instruction information, where the first instruction information indicates not to update the first information.

[0390] In a possible implementation, the processing unit 901 processing the first information based on the first message includes, if the first message does not include first instruction information, the processing unit 901 updating the first information based on a cell corresponding to the first message, and the first instruction information indicates not to update the first information.

[0391] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0392] In a possible implementation, if any of the following is met, the processing unit 901 determining that access stratum security between the terminal device and the network device is not activated includes: the processing unit 901 determining that a security mode command message is not received; and after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that a process of obtaining a key based on the security mode command message has failed; or after the transceiver unit 902 receives the security mode command message, the processing unit 901 determining that integrity protection verification corresponding to the security mode command message has failed.

[0393] In a possible implementation, the transceiver unit 902 is further configured to transmit first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0394] In a possible implementation, the transceiver unit 902 is further configured to receive third indication information, where the third indication information indicates that the network device supports the PEI.

[0395] In a possible implementation, when the apparatus 900 is configured to perform the method performed by the network device in the above embodiment, the apparatus includes a processing unit 901 and a transceiver unit 902. When the transceiver unit 902 transmits a first message and access stratum security between the terminal device and the network device is not activated, the processing unit 901 processes second information based on the first message, where the second information indicates one or more cells accessed by the terminal device, and the first message indicates releasing a radio resource control (RRC) connection between the terminal device and the network device. The processing unit 901 releases the RRC connection.

[0396] In a possible implementation, the processing unit 901 processing the second information based on the first message includes the processing unit 901 determining not to update the second information if the first message includes first instruction information, where the first instruction information indicates not to update the first information, and the first information indicates information regarding a last used cell of the terminal device.

[0397] In a possible implementation, the processing unit 901 processing the first information based on the first message includes, if the first message does not include first instruction information, the processing unit 901 updating the second information based on a cell corresponding to the first message, where the first instruction information indicates not to update the first information, and the first information indicates information regarding a last-used cell of the terminal device.

[0398] In a possible implementation, the first information includes information about a last used cell of the terminal device.

[0399] In a possible implementation, the second information includes identifiers of one or more cells accessed by the terminal device.

[0400] In a possible implementation form, the processing unit 901 determines, based on the first message, whether the terminal device updates the first information.

[0401] In a possible implementation, the transceiver unit 902 is further configured to receive first capability information, where the first capability information indicates that the terminal device supports a paging progress indication PEI.

[0402] In a possible implementation, the transceiver unit 902 is further configured to transmit third indication information, where the third indication information indicates that the network device supports the PEI.

[0403] Please note that for the contents such as information execution processes of the units of the communication device 900, please specifically refer to the description of the preceding method embodiments in the present application, and the details will not be described again in this specification.

[0404] 10 is another diagram of the structure of a communication device 1000 according to the present application. The communication device 1000 includes at least an input / output interface 1002. The communication device 1000 may be a chip or an integrated circuit.

[0405] Optionally, the communication device further comprises a logic circuit 1001 .

[0406] The transceiver unit 902 shown in Figure 9 may be a communication interface. The communication interface may be the input / output interface 1002 of Figure 10, which may include an input interface and an output interface. Alternatively, the communication interface may be a transceiver circuit, which may include an input interface circuit and an output interface circuit.

[0407] Optionally, when the communications apparatus 1000 is a terminal device (or a component within the device) in the above-described embodiment, and the input / output interface 1002 receives the first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 determines not to update the first information, the first information indicates a last used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The logic circuit 1001 releases the RRC connection.

[0408] Optionally, when the communications apparatus 1000 is a network device (or a component within a device) in the above-described embodiment, and the input / output interface 1002 is sending a first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 determines not to update the second information, the second information indicating one or more cells accessed by the terminal device, and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device. The logic circuit 1001 releases the RRC connection.

[0409] Optionally, when the communication apparatus 1000 is a terminal device (or a component within the device) in the above-described embodiment, and the input / output interface 1002 receives the first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 determines not to ignore first indication information in the first message, or ignores at least one piece of information in the first message except for the first indication information and the second indication information. The first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The logic circuit 1001 releases the RRC connection.

[0410] Optionally, when the communication apparatus 1000 is a network device (or a component within the device) in the above-described embodiment, the input / output interface 1002 is transmitting a first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 determines not to ignore first indication information in the first message, or the logic circuit 1001 ignores at least one piece of information in the first message except for the first indication information and the second indication information. The first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update the first information, the first information indicates a last-used cell of the terminal device, and the second indication information indicates a waiting time for accessing the network. The logic circuit 1001 releases the RRC connection.

[0411] Optionally, when the communications apparatus 1000 is a terminal device (or a component within the device) in the above-described embodiment, and the input / output interface 1002 receives a first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 processes first information based on the first message, where the first information indicates information about a last-used cell of the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The logic circuit 1001 releases the RRC connection.

[0412] Optionally, when the communications apparatus 1000 is a network device (or a component within a device) in the above-described embodiment, and the input / output interface 1002 is sending a first message, and access stratum security between the terminal device and the network device is not activated, the logic circuit 1001 processes second information based on the first message, where the second information indicates one or more cells accessed by the terminal device, and the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device. The logic circuit 1001 releases the RRC connection.

[0413] The logic circuit 1001 and the input / output interface 1002 can further perform other steps performed by the network device in any of the embodiments to achieve corresponding beneficial effects, and the details will not be described again in this specification.

[0414] In a possible implementation, the processing unit 901 shown in FIG. 9 may be the logic circuit 1001 of FIG.

[0415] Optionally, logic circuitry 1001 may be a processing unit, and some or all of the functionality of the processing unit may be implemented by software. Some or all of the functionality of the processing unit may be implemented via software.

[0416] Optionally, the processing device may include a memory and a processor, wherein the memory is configured to store a computer program, and the processor reads and executes the computer program stored in the memory to perform corresponding processes and / or steps in any method embodiment.

[0417] Optionally, the processing device may include only a processor. A memory configured to store a computer program is located external to the processing device, and the processor is connected to the memory via circuits / wires to read and execute the computer program stored in the memory. The memory and the processor may be integrated together or may be physically separate.

[0418] Optionally, the processing device may be one or more chips or one or more integrated circuits. For example, the processing device may be one or more field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), systems on chips (SoCs), central processing units (CPUs), network processors (NPs), digital signal processors (DSPs), microcontroller units (MCUs), programmable logic devices (PLDs) or other integrated chips, or any combination of the aforementioned chips or processors.

[0419] 11 illustrates a communication device 1100 in the aforementioned embodiment according to an embodiment of the present application. Specifically, the communication device 1100 may be a communication device that functions as a terminal device in the aforementioned embodiment. The example illustrated in FIG. 11 is an example in which the terminal device is implemented as a terminal device (or a component within a terminal device).

[0420] In a possible illustration of the logical structure of the communication device 1100, the communication device 1100 may include, but is not limited to, at least one processor 1101 and a communication port 1102.

[0421] Further, optionally, the device may include at least one of a memory 1103 and a bus 1104. In this embodiment of the present application, the at least one processor 1101 is configured to perform control processes for the operation of the communication device 1100.

[0422] Additionally, the processor 1101 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor may implement or be implemented with various exemplary logic blocks, modules, and circuits described with reference to the contents disclosed in this application. Alternatively, the processor may be a combination of processors that implement a computing function, such as a combination of one or more microprocessors, or a combination of a digital signal processor and a microprocessor. For the sake of convenience, those skilled in the art may clearly understand that the detailed operation processes of the above-mentioned systems, devices, and units may refer to the corresponding processes in the above-mentioned method embodiments. Details will not be described again in this specification.

[0423] It should be noted that the communication device 1100 shown in Fig. 11 may be specifically configured to implement the steps implemented by the terminal device in the above-mentioned method embodiments and to implement the corresponding technical effects for the terminal device. For the specific implementation form of the communication device shown in Fig. 11, please refer to the description of the above-mentioned method embodiments. Details will not be described again in this specification.

[0424] 12 is a diagram of the structure of a communication device 1200 in the aforementioned embodiment according to one embodiment of the present application. The communication device 1200 may specifically be a communication device used as a network device in the aforementioned embodiment. In the example shown in FIG. 12, the network device is implemented using a network device (or a component within a network device). For the configuration of the communication device, please refer to the configuration shown in FIG. 12.

[0425] The communication device 1200 includes at least one processor 1211 and at least one network interface 1214. Optionally, the communication device further includes at least one memory 1212, at least one transceiver 1213, and one or more antennas 1215. The processor 1211, the memory 1212, the transceiver 1213, and the network interface 1214 are connected, for example, via a bus. In this embodiment of the present application, the connection may include various interfaces, transmission lines, buses, or the like. This is not limited to this embodiment. The antenna 1215 is connected to the transceiver 1213. The network interface 1214 is configured to enable the communication device to communicate with another communication device over a communication link. For example, the network interface 1214 may include a network interface between the communication device and a core network device, such as an S1 interface. The network interface may include a network interface between the communication device and another communication device (e.g., another network device or a core network device), such as an X2 or Xn interface.

[0426] The processor 1211 is primarily configured to process communication protocols and communication data, control the entire communication device, execute software programs, and process data of the software programs, for example, to support the communication device in performing the operations described in the embodiments. The communication device may include a baseband processor and a central processing unit. The baseband processor is primarily configured to process communication protocols and communication data. The central processing unit is primarily configured to control the entire terminal device, execute software programs, and process data of the software programs. The functions of the baseband processor and the central processing unit may be integrated into the processor 1211 in FIG. 12. Those skilled in the art will understand that the baseband processor and the central processing unit may alternatively be independent processors and interconnected using technology such as a bus. Those skilled in the art will understand that a terminal device may include multiple baseband processors to accommodate different network standards, multiple central processing units to increase the processing capabilities of the terminal device, and components of the terminal device may be connected using various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The central processing unit may also be referred to as a central processing circuit or a central processing chip. The functionality for processing communication protocols and communication data may be built into the processor or may be stored in memory in the form of a software program, which the processor executes to implement the baseband processing functionality.

[0427] The memory is mainly configured to store software programs and data. The memory 1212 may exist independently and be connected to the processor 1211. Optionally, the memory 1212 may alternatively be integrated with the processor 1211. For example, the memory 1212 and the processor 1211 are integrated into one chip. The memory 1212 can store program codes for implementing the technical solutions in the embodiments of the present application, and the processor 1211 controls the execution of the program codes. Various types of computer program codes that are executed may also be considered as drivers for the processor 1211.

[0428] FIG. 12 shows only one memory and one processor. In an actual terminal device, there may be multiple processors and multiple memories. The memory may also be referred to as a storage medium, a storage device, or the like. The memory may be a storage element on the same chip as the processor, i.e., an on-chip storage element, or may be an independent storage element. This is not limited to this embodiment of the present application.

[0429] The transceiver 1213 may be configured to support reception or transmission of radio frequency signals between a communication device and a terminal, and the transceiver 1213 may be connected to an antenna 1215. The transceiver 1213 includes a transmitter Tx and a receiver Rx. Specifically, the one or more antennas 1215 can receive radio frequency signals. The receiver Rx of the transceiver 1213 is configured to receive the radio frequency signals from the antenna, convert the radio frequency signals to digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or digital intermediate frequency signals to the processor 1211, so that the processor 1211 performs further processing, such as demodulation and decoding, on the digital baseband signals or digital intermediate frequency signals. In addition, the transmitter Tx of the transceiver 1213 is further configured to receive modulated digital baseband signals or modulated digital intermediate frequency signals from the processor 1211, convert the modulated digital baseband signals or modulated digital intermediate frequency signals to radio frequency signals, and transmit the radio frequency signals via the one or more antennas 1215. Specifically, the receiver Rx can selectively perform one-level or multi-level down-frequency mixing and analog-to-digital conversion on the radio frequency signal to obtain a digital baseband signal or a digital intermediate frequency signal. The sequence of the down-frequency mixing and analog-to-digital conversion is adjustable. The transmitter Tx can selectively perform one-level or multi-level up-frequency mixing and digital-to-analog conversion on the modulated digital baseband signal or the digital intermediate frequency signal to obtain a radio frequency signal. The order of the up-frequency mixing and digital-to-analog conversion is adjustable. The digital baseband signal and the digital intermediate frequency signal are sometimes collectively referred to as a digital signal.

[0430] The transceiver 1213 may also be referred to as a transceiver unit, a transceiver machine, a transceiver device, etc. Optionally, a component configured to implement a receiving function within the transceiver unit may be considered a receiving unit, and a component configured to implement a transmitting function within the transceiver unit may be considered a transmitting unit. In other words, the transceiver unit includes a receiving unit and a transmitting unit. The receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc. The transmitting unit may be referred to as a transmitter machine, a transmitter, a transmitting circuit, etc.

[0431] It should be noted that the communication device 1200 shown in Fig. 12 may be specifically configured to implement the steps implemented by the network device in the above-mentioned method embodiments, and achieve technical effects corresponding to the technical effects achieved by the network device. For specific implementation forms of the communication device 1200 shown in Fig. 12, please refer to the description of the above-mentioned method embodiments. Details will not be described again in this specification.

[0432] An embodiment of the present application further provides a computer-readable storage medium storing one or more computer-executable instructions, which, when executed by a processor, cause the processor to perform a method in a possible implementation of the terminal device in the aforementioned embodiment.

[0433] An embodiment of the present application further provides a computer-readable storage medium storing one or more computer-executable instructions, which, when executed by a processor, cause the processor to perform a method in a possible implementation of the network device in the aforementioned embodiment.

[0434] An embodiment of the present application further provides a computer program product (also called a computer program) storing one or more computer programs, which, when executed by a processor, causes the processor to perform a method in a possible implementation of the aforementioned terminal device.

[0435] An embodiment of the present application further provides a computer program product storing one or more computer programs, which, when executed by a processor, causes the processor to perform a method in a possible implementation of the aforementioned network device.

[0436] An embodiment of the present application further provides a chip system. The chip system includes at least one processor configured to support the communication device in implementing functions in a possible implementation of the above-described communication device. Optionally, the chip system further includes an interface circuit, which provides program instructions and / or data to the at least one processor. In a possible design, the chip system may further include a memory. The memory is configured to store instructions and data required for programming the communication device. The chip system may include a chip, or may include a chip and another discrete component. The communication device may specifically be a terminal device in the above-described method embodiment.

[0437] An embodiment of the present application further provides a chip system. The chip system includes at least one processor configured to support the communication device in implementing functions in a possible implementation of the communication device described above. Optionally, the chip system further includes an interface circuit, which provides program instructions and / or data to the at least one processor. In a possible design, the chip system may further include a memory. The memory is configured to store program instructions and data required for the communication device. The chip system may include a chip or may include a chip and another discrete component. The communication device may specifically be a network device in the embodiment of the method described above.

[0438] An embodiment of the present application further provides a communication system, the communication system including the terminal device and the network device in any one of the preceding embodiments.

[0439] In some embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. For example, the described device embodiments are merely examples. For example, the division into units is merely a division of logical functions, and other divisions may occur in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electronic or other forms.

[0440] Units described as separate parts may or may not be physically separate, and parts presented as units may or may not be physical units, i.e., located in one location or distributed across multiple network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0441] The functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The integrated unit may be implemented in the form of hardware or in the form of a software functional unit. When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may essentially be implemented in the form of a software product, or a portion of the technical solution may be implemented in the form of a software product. The computer software product may be stored in a storage medium and include instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to perform all or part of the steps of the method described in the embodiments of the present application. The storage medium may include any medium capable of storing program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk. [Explanation of symbols]

[0442] 1 Terminal Devices, System Information Blocks, Terminal Devices Subgroup 2 Terminal Devices, Terminal Devices subgroup 3 Terminal Devices 4 Terminal Devices 5 Terminal Devices 6 Terminal Devices 900 Communication Equipment 901 Processing Unit 902 Transceiver Unit 1000 Communication Equipment 1001 Logic Circuit 1002 Input / Output Interface 1100 Communication equipment 1101 processor 1102 communication port 1103 Memory 1104 Bus 1200 Communication Equipment 1211 processor 1212 memory 1213 Transceiver 1214 Network Interface 1215 Antenna

Claims

1. 1. A communication method comprising: a terminal device receiving a first message and determining not to update first information if access stratum security between the terminal device and the network device is not activated, the first information indicating a last used cell of the terminal device and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device; releasing the RRC connection; A method comprising:

2. the first message includes first indication information, the first indication information indicating that the first information should not be updated, and the method further comprises: ignoring the first indication information if the access stratum security between the terminal device and the network device is not activated. The method of claim 1 further comprising:

3. the first message includes second instruction information, the second instruction information indicating a waiting time for accessing a network, and the method further comprises: ignoring at least one piece of information in the first message except for the second instruction information, the at least one piece of information including the first instruction information, the first instruction information indicating not to update the first information; 3. The method of claim 1 or 2, further comprising:

4. The method according to claim 1 , wherein the first information includes information about the last used cell of the terminal device.

5. 1. A communication method comprising: determining not to update second information when a network device is sending a first message and access stratum security between a terminal device and the network device is not activated, the second information indicating one or more cells accessed by the terminal device and the first message indicating to release a radio resource control (RRC) connection between the terminal device and the network device; releasing the RRC connection; A method comprising:

6. the first message includes first indication information, the first indication information indicates that the first information is not to be updated, the first information indicates a last used cell of the terminal device, and the method includes: determining that the terminal device ignores the first indication information if the access stratum security between the terminal device and the network device is not activated; 6. The method of claim 5, further comprising:

7. the first message includes second instruction information, the second instruction information indicating a waiting time for accessing a network, and the method further comprises: determining, when the access stratum security between the terminal device and the network device is not activated, that the terminal device ignores at least one information in the first message except for the second indication information, the at least one information including the first indication information, the first indication information indicating not to update the first information, and the first information indicating the last used cell of the terminal device; 7. The method of claim 5 or 6, further comprising:

8. determining by the terminal device not to update the first information if the access stratum security between the terminal device and the network device is not activated, the first information indicating the last used cell of the terminal device; 8. The method of claim 5, further comprising:

9. The method according to claim 5 , wherein the first information comprises information about the last used cell of the terminal device.

10. 10. The method according to claim 5, wherein the second information comprises identifiers of the one or more cells accessed by the terminal device.

11. 1. A communication method comprising: a terminal device receiving a first message, and when access stratum security between the terminal device and the network device is not activated, deciding not to ignore first indication information in the first message or to ignore at least one piece of information in the first message except first indication information and second indication information, wherein the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update first information, the first information indicates a last used cell of the terminal device, and the second indication information indicates a waiting time for accessing a network; releasing the RRC connection; A method comprising:

12. determining, by the terminal device, based on the first indication information, not to update the first information; 12. The method of claim 11, further comprising:

13. The method according to claim 11 or 12, wherein the first information includes information about the last used cell of the terminal device.

14. 1. A communication method comprising: determining, when a network device is sending a first message and access stratum security between a terminal device and the network device is not activated, not to ignore first indication information in the first message or to ignore at least one piece of information in the first message except first indication information and second indication information, wherein the first message indicates to release a radio resource control (RRC) connection between the terminal device and the network device, the first indication information indicates not to update first information, the first information indicates a last used cell of the terminal device, and the second indication information indicates a waiting time for accessing a network; releasing the RRC connection; A method comprising:

15. determining, based on the first indication information, not to update second information, the second information indicating one or more cells accessed by the terminal device; 15. The method of claim 14, further comprising:

16. The method of claim 15 , wherein the second information includes identifiers of the one or more cells accessed by the terminal device.

17. 17. The method according to claim 14, wherein the first information comprises information about the last used cell of the terminal device.

18. determining by the network device that the terminal device will not ignore the first indication information in the first message, or that the terminal device will ignore at least one piece of information in the first message excluding the first indication information and the second indication information, when the access stratum security between the terminal device and the network device is not activated; 18. The method of any one of claims 14 to 17, further comprising:

19. A communication device comprising a processing unit and a transceiver unit, The processing unit and the transceiver unit are configured to perform the method of any one of claims 1 to 18. Communication equipment.

20. A communication device comprising: a logic circuit; and an input / output interface; The logic circuit and the input / output interface are configured to perform the method of any one of claims 1 to 18. Communication equipment.

21. 1. A communications device, comprising: at least one processor coupled to a memory; the memory is configured to store programs and / or instructions; The at least one processor is configured to enable the communication device to perform the method according to any one of claims 1 to 18 based on the program and / or the instructions. Communication equipment.

22. 19. A computer-readable storage medium having stored thereon instructions that, when executed by a computer, perform the method of any one of claims 1 to 18.

23. 19. A computer program product comprising instructions that, when executed on a computer, enable the computer to carry out the method of any one of claims 1 to 18.

24. A communication system comprising a terminal device and a network device, The terminal device is configured to perform the method according to any one of claims 1 to 4 and the network device is configured to perform the method according to any one of claims 5 to 10, or The terminal device is configured to perform the method according to any one of claims 11 to 13, and the network device is configured to perform the method according to any one of claims 14 to 18. Communication system.

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