Communication methods, communication device, communication system, storage medium, and program product

Abstract

The present disclosure relates to communication methods, a communication device, a communication system, a storage medium and a program product. A communication method is performed by a first network device. The method comprises: receiving a first message sent by a terminal, the first message being used for the terminal to request establishing a radio resource control (RRC) connection to a first network device; and sending to the terminal one of the following: an RRC connection recovery message, and an RRC connection establishment message, wherein the first network device does not support a first security algorithm which is used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection. The communication method can improve the efficiency of terminals in inactive states accessing networks.

Description

Communication methods, communication equipment, communication systems, storage media and software products Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to a communication method, communication device, communication system, storage medium, and program product. Background Technology

[0002] Currently, network environments have introduced an RRC inactive state in the terminal's radio resource control (RRC) state. When data transmission is not required, the terminal remains in the RRC inactive state, reducing communication with the network, thereby saving power and lowering network connection latency. Summary of the Invention

[0003] Improving the efficiency of terminals accessing the network in an inactive state is a problem that needs to be solved.

[0004] This disclosure provides a communication method, communication device, communication system, storage medium, and program product.

[0005] According to a first aspect of the present disclosure, a communication method is provided, executed by a first network device, the method comprising: receiving a first message sent by a terminal, the first message being used by the terminal to request the establishment of an RRC connection with the first network device; sending to the terminal one of the following: an RRC connection recovery message; an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0006] According to a second aspect of the present disclosure, a communication method is provided, executed by a terminal, the method comprising: sending a first message to a first network device, the first message being used to request the establishment of an RRC connection with the first network device; receiving an RRC connection recovery message or an RRC connection establishment message sent by the first network device; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0007] According to a third aspect of the present disclosure, a communication method is provided, executed by a second network device. The method includes: receiving a context request message sent by a first network device, the context request message including fifth information, the fifth information being used to indicate a security algorithm supported by the first network device; and sending a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to a terminal.

[0008] According to a fourth aspect of the present disclosure, a communication method is proposed, applied to a communication system, the communication system including a first network device and a terminal. The method includes: the terminal sending a first message to the first network device, the first message being used to request the establishment of an RRC connection with the first network device; the first network device sending one of the following to the terminal: an RRC connection recovery message; an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0009] According to a fifth aspect of the present disclosure, a communication method is proposed for use in a communication system, the communication system including a first network device and a second network device. The method includes: the first network device sending a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate a security algorithm supported by the first network device; the second network device sending a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, and the context response message being used to trigger the first network device to send an RRC connection restoration message to a terminal.

[0010] According to a sixth aspect of the present disclosure, a communication apparatus is provided, deployed on a first network device. The communication apparatus includes: a transceiver module, configured to receive a first message sent by a terminal, the first message being for the terminal to request the establishment of an RRC connection with the first network device; and to send to the terminal one of the following: an RRC connection restoration message; or an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0011] According to a seventh aspect of the present disclosure, a communication device is provided, deployed on a terminal. The communication device includes: a transceiver module, configured to send a first message to a first network device, the first message being used to request the establishment of an RRC connection with the first network device; and to receive an RRC connection recovery message or an RRC connection establishment message sent by the first network device; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0012] According to an eighth aspect of the present disclosure, a communication apparatus is provided, deployed on a second network device. The communication apparatus includes: a transceiver module, configured to receive a context request message sent by a first network device, the context request message including fifth information, the fifth information indicating a security algorithm supported by the first network device; and, based on the context request message, to send a context response message to the first network device, the context response message instructing the first network device to restore the RRC connection using a context-free approach, the context response message triggering the first network device to send an RRC connection restoration message to a terminal.

[0013] According to a ninth aspect of the present disclosure, a communication device is provided, comprising: one or more processors, and one or more memories for storing a computer program; wherein the processor executes the computer program to implement the steps of the communication methods described in the first, second, and third aspects.

[0014] According to a tenth aspect of the present disclosure, a communication system is provided, including a first network device and a terminal, wherein the terminal is configured to send a first message to the first network device, the first message being used to request the establishment of an RRC connection with the first network device; the first network device is configured to send one of the following to the terminal: an RRC connection recovery message; an RRC connection establishment message, wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0015] According to an eleventh aspect of the present disclosure, a communication system is provided, including a first network device and a second network device, wherein the first network device is configured to send a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; the second network device is configured to send a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free method, and the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0016] According to a twelfth aspect of the present disclosure, a computer-readable storage medium is provided that stores a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the communication methods described in the first, second, and third aspects above.

[0017] According to a thirteenth aspect of the present disclosure, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the steps of the communication methods described in the first, second, and third aspects above.

[0018] According to a fourteenth aspect of the present disclosure, a computer program is provided that includes code, which, when executed by a processor, implements the steps of the communication methods described in the first, second, and third aspects above.

[0019] The technical solutions provided in this disclosure can improve the efficiency of a terminal accessing the network in an inactive state. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments of the invention.

[0021] Figure 1A is a schematic diagram of the architecture of a communication system according to an embodiment of the present disclosure.

[0022] Figure 1B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0023] Figure 1C is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0024] Figure 1D is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0025] Figure 1E is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0026] Figure 1F is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0027] Figure 1G is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0028] Figure 2A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0029] Figure 2B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0030] Figure 2C is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0031] Figure 2D is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0032] Figure 2E is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0033] Figure 3A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0034] Figure 3B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0035] Figure 3C is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0036] Figure 4A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0037] Figure 4B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0038] Figure 5A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0039] Figure 5B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure.

[0040] Figure 6 is a schematic diagram of the structure of a communication device according to an embodiment of the present disclosure.

[0041] Figure 7A is a schematic diagram of the structure of a communication device according to an embodiment of the present disclosure.

[0042] Figure 7B is a schematic diagram of the chip structure according to an embodiment of the present disclosure. Detailed Implementation

[0043] This disclosure provides a communication method, communication device, communication system, storage medium, and program product.

[0044] In a first aspect, embodiments of this disclosure propose a communication method executed by a first network device. The method includes: receiving a first message sent by a terminal, the first message being used by the terminal to request the establishment of an RRC connection with the first network device; and sending one of the following to the terminal: an RRC connection recovery message; or an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0045] In the above embodiments, if the first network device does not support the first security algorithm used by the terminal before entering the inactive state, it sends an RRC connection recovery message or an RRC connection establishment message to the terminal, so that the terminal can quickly roll back according to the RRC connection establishment message or quickly update the key according to the RRC connection recovery message, thereby reducing the latency of the RRC connection and improving the efficiency of the RRC connection.

[0046] In conjunction with some embodiments of the first aspect, in some embodiments, the above method further includes: sending first information to the terminal, the first information being used to instruct the terminal to use a second security algorithm for security protection and integrity protection, the second security algorithm being different from the first security algorithm.

[0047] In conjunction with some embodiments of the first aspect, in some embodiments, the first information is carried in downlink signaling associated with the transport block (TB) where the RRC connection recovery message is located. The downlink signaling includes one of the following: downlink control information (DCI) for scheduling the TB; medium access control (MAC) control element (CE); and RRC signaling.

[0048] In conjunction with some embodiments of the first aspect, in some embodiments, the downlink signaling is MAC CE or RRC signaling, and the first information is not encrypted.

[0049] In conjunction with some embodiments of the first aspect, in some embodiments, the above method further includes: sending a context request message to a second network device according to a first message, the context request message being used to request context information of the terminal, the first message being an RRC connection recovery request message; receiving the context information of the terminal sent by the second network device according to the context request message, the context information including a first security algorithm; and determining, based on the context information of the terminal, that the first network device does not support the first security algorithm.

[0050] In conjunction with some embodiments of the first aspect, in some embodiments, the above method further includes: using a third security algorithm to perform security and integrity protection on the RRC connection recovery message, wherein the third security algorithm is determined based on predefined information.

[0051] In conjunction with some embodiments of the first aspect, in some embodiments the above method further includes: broadcasting second information, the second information being used to indicate a security algorithm supported by the first network device, and the second information being used to trigger the terminal to send a first message.

[0052] In conjunction with some embodiments of the first aspect, in some embodiments, the security algorithm supported by the first network device does not include the first security algorithm, and the first message is an RRC connection establishment request message.

[0053] In conjunction with some embodiments of the first aspect, in some embodiments, the first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that the first security algorithm is not supported.

[0054] In conjunction with some embodiments of the first aspect, in some embodiments the above method further includes: sending a second message to a second network device, the second message being used to instruct the second network device to release the context information of the terminal.

[0055] In conjunction with some embodiments of the first aspect, in some embodiments, the above method further includes: receiving an RRC connection establishment complete message sent by the terminal according to the RRC connection establishment message, the RRC connection establishment complete message including fourth information, the fourth information being used to instruct the first network device to perform RRC reconfiguration according to the terminal's access layer context information.

[0056] In conjunction with some embodiments of the first aspect, in some embodiments, the above method further includes: sending a context request message to a second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; receiving a context response message sent by the second network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0057] In conjunction with some embodiments of the first aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated one-to-one with a data radio bearer (DRB), and the RRC connection recovery message includes the sixth information.

[0058] In conjunction with some embodiments of the first aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0059] In conjunction with some embodiments of the first aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0060] Secondly, embodiments of this disclosure propose a communication method executed by a terminal. The method includes: sending a first message to a first network device, the first message being used to request the establishment of an RRC connection with the first network device; receiving an RRC connection recovery message or an RRC connection establishment message sent by the first network device; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0061] In the above embodiments, since the first network device sends an RRC connection recovery message or an RRC connection establishment message to the terminal when it does not support the first security algorithm used by the terminal before entering the inactive state, the terminal can quickly roll back according to the RRC connection establishment message or quickly update the key according to the RRC connection recovery message, thereby reducing the latency of the RRC connection and improving the efficiency of the RRC connection.

[0062] In conjunction with some embodiments of the second aspect, in some embodiments, the above method further includes: receiving first information sent by a first network device, the first information being used to instruct the terminal to use a second security algorithm for security protection and integrity protection, the second security algorithm being different from the first security algorithm.

[0063] In conjunction with some embodiments of the second aspect, in some embodiments, the first information is carried in the downlink signaling associated with the TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: DCI, used for scheduling the TB; MAC CE; RRC signaling.

[0064] In conjunction with some embodiments of the second aspect, in some embodiments, the downlink signaling is MAC CE or RRC signaling, and the first information is not encrypted.

[0065] In conjunction with some embodiments of the second aspect, in some embodiments, the RRC connection recovery message is protected for security and integrity by a third security algorithm, which is determined based on predefined information.

[0066] In conjunction with some embodiments of the second aspect, in some embodiments, the above method further includes: receiving second information broadcast by the first network device, the second information being used to indicate the security algorithm supported by the first network device, and the second information being used to trigger the terminal to send a first message.

[0067] In conjunction with some embodiments of the second aspect, in some embodiments, the security algorithm supported by the first network device does not include a first security algorithm, and the first message is an RRC connection establishment request message.

[0068] In conjunction with some embodiments of the second aspect, in some embodiments, the first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that the first security algorithm is not supported.

[0069] In conjunction with some embodiments of the second aspect, in some embodiments, the above method further includes: sending an RRC connection establishment completion message to a first network device according to the RRC connection establishment message, the RRC connection establishment completion message including fourth information, the fourth information being used to instruct the first network device to perform RRC reconfiguration according to the access layer context information of the terminal.

[0070] Thirdly, embodiments of this disclosure propose a communication method executed by a second network device. The method includes: receiving a context request message sent by a first network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; and sending a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0071] In the above embodiments, since the fifth information is used to indicate the security algorithms supported by the first network device, the second network device can determine whether the first network device supports the security algorithms used by the terminal based on the security algorithms supported by the first network device. If it is determined that the first network device does not support the security algorithms used by the terminal, the second network device instructs the first network device to restore the RRC connection using a context-free approach. In this way, there is no need for complex context information synchronization and migration operations between the terminal and the first network device, which can significantly reduce the signaling interaction required during the RRC connection restoration process, thereby reducing signaling overhead. Moreover, due to the reduction in context migration and complex signaling interaction, the terminal can restore to the RRC connection state more quickly, thereby reducing the latency of RRC connection restoration and improving RRC connection efficiency.

[0072] In conjunction with some embodiments of the third aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated with a DRB one-to-one, and the RRC connection recovery message includes the sixth information.

[0073] In conjunction with some embodiments of the third aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0074] In conjunction with some embodiments of the third aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0075] Fourthly, embodiments of this disclosure provide a communication method applied to a communication system, the communication system including a first network device and a terminal, the method including: the terminal sending a first message to the first network device, the first message being used to request the establishment of an RRC connection with the first network device; the first network device sending one of the following to the terminal: an RRC connection recovery message; an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0076] In conjunction with some embodiments of the fourth aspect, in some embodiments, the above method further includes: a first network device sending first information to a terminal, the first information being used to instruct the terminal to use a second security algorithm for security and integrity protection, the second security algorithm being different from the first security algorithm.

[0077] In conjunction with some embodiments of the fourth aspect, in some embodiments, the first information is carried in the downlink signaling associated with the transport block TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: DCI for scheduling TB; MAC CE; RRC signaling.

[0078] In conjunction with some embodiments of the fourth aspect, in some embodiments, the downlink signaling is MAC CE or RRC signaling, and the first information is not encrypted.

[0079] In conjunction with some embodiments of the fourth aspect, in some embodiments, the communication system further includes a second network device, and the above method further includes: the first network device sending a context request message to the second network device according to a first message, the context request message being used to request context information of the terminal, the first message being an RRC connection recovery request message; the second network device sending the context information of the terminal to the first network device according to the context request message, the context information including a first security algorithm; the first network device determining, based on the context information of the terminal, that the first network device does not support the first security algorithm.

[0080] In conjunction with some embodiments of the fourth aspect, in some embodiments, the above method further includes: a first network device using a third security algorithm to perform security and integrity protection on the RRC connection recovery message, wherein the third security algorithm is determined based on predefined information.

[0081] In conjunction with some embodiments of the fourth aspect, in some embodiments, the above method further includes: a first network device broadcasting second information, the second information being used to indicate a security algorithm supported by the first network device, and the second information being used to trigger a terminal to send a first message.

[0082] In conjunction with some embodiments of the fourth aspect, in some embodiments, the security algorithm supported by the first network device does not include the first security algorithm, and the first message is an RRC connection establishment request message.

[0083] In conjunction with some embodiments of the fourth aspect, in some embodiments, the first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that the first security algorithm is not supported.

[0084] In conjunction with some embodiments of the fourth aspect, in some embodiments, the communication system further includes a second network device, and the above method further includes: the first network device sending a second message to the second network device, the second message being used to instruct the second network device to release the context information of the terminal.

[0085] In conjunction with some embodiments of the fourth aspect, in some embodiments, the above method further includes: the terminal sending an RRC connection establishment completion message to the first network device according to the RRC connection establishment message, the RRC connection establishment completion message including fourth information, the fourth information being used to instruct the first network device to perform RRC reconfiguration according to the terminal's access layer context information.

[0086] In conjunction with some embodiments of the fourth aspect, in some embodiments, the communication system further includes a second network device, and the above method further includes: the first network device sending a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; the second network device sending a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, and the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0087] In conjunction with some embodiments of the fourth aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated with a DRB one-to-one, and the RRC connection recovery message includes the sixth information.

[0088] In conjunction with some embodiments of the fourth aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0089] In conjunction with some embodiments of the fourth aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0090] Fifthly, embodiments of this disclosure provide a communication method applied to a communication system, the communication system including a first network device and a second network device. The method includes: the first network device sending a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; the second network device sending a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to a terminal.

[0091] In conjunction with some embodiments of the fifth aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated with a DRB one-to-one, and the RRC connection recovery message includes the sixth information.

[0092] In conjunction with some embodiments of the fifth aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0093] In conjunction with some embodiments of the fifth aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0094] Sixthly, embodiments of this disclosure provide a communication device deployed on a first network device. The communication device includes: a transceiver module, configured to receive a first message sent by a terminal, the first message being used by the terminal to request the establishment of an RRC connection with the first network device; and to send to the terminal one of the following: an RRC connection restoration message; or an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0095] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to send first information to the terminal, the first information being used to instruct the terminal to use a second security algorithm for security protection and integrity protection, the second security algorithm being different from the first security algorithm.

[0096] In conjunction with some embodiments of the sixth aspect, in some embodiments, the first information is carried in the downlink signaling associated with the TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: DCI, used for scheduling the TB; MAC CE; RRC signaling.

[0097] In conjunction with some embodiments of the sixth aspect, in some embodiments, the downlink signaling is MAC CE or RRC signaling, and the first information is not encrypted.

[0098] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to send a context request message to the second network device according to the first message, the context request message being used to request context information of the terminal, the first message being an RRC connection recovery request message; receive the context information of the terminal sent by the second network device according to the context request message, the context information including a first security algorithm; the communication device further includes: a processing module, configured to determine, based on the context information of the terminal, that the first network device does not support the first security algorithm.

[0099] In conjunction with some embodiments of the sixth aspect, in some embodiments, the communication device further includes: a processing module for performing security and integrity protection on the RRC connection recovery message using a third security algorithm, the third security algorithm being determined based on predefined information.

[0100] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to broadcast second information, the second information being used to indicate the security algorithm supported by the first network device, and the second information being used to trigger the terminal to send the first message.

[0101] In conjunction with some embodiments of the sixth aspect, in some embodiments, the security algorithm supported by the first network device does not include a first security algorithm, and the first message is an RRC connection establishment request message.

[0102] In conjunction with some embodiments of the sixth aspect, in some embodiments, the first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that the first security algorithm is not supported.

[0103] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to send a second message to the second network device, the second message being used to instruct the second network device to release the context information of the terminal.

[0104] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to receive an RRC connection establishment completion message sent by the terminal according to the RRC connection establishment message. The RRC connection establishment completion message includes fourth information, which is used to instruct the first network device to perform RRC reconfiguration according to the terminal's access layer context information.

[0105] In conjunction with some embodiments of the sixth aspect, in some embodiments, the transceiver module is further configured to send a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; and to receive a context response message sent by the second network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0106] In conjunction with some embodiments of the sixth aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated with a DRB one-to-one, and the RRC connection recovery message includes the sixth information.

[0107] In conjunction with some embodiments of the sixth aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0108] In conjunction with some embodiments of the sixth aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0109] In a seventh aspect, embodiments of this disclosure provide a communication device deployed on a terminal. The communication device includes: a transceiver module, configured to send a first message to a first network device, the first message being used to request the establishment of an RRC connection with the first network device; and to receive an RRC connection recovery message or an RRC connection establishment message sent by the first network device; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security and integrity protection.

[0110] In conjunction with some embodiments of the seventh aspect, in some embodiments, the transceiver module is further configured to receive first information sent by the first network device, the first information being used to instruct the terminal to use a second security algorithm for security protection and integrity protection, the second security algorithm being different from the first security algorithm.

[0111] In conjunction with some embodiments of the seventh aspect, in some embodiments, the first information is carried in downlink signaling associated with the transport block TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: DCI for scheduling TB; MAC CE; RRC signaling.

[0112] In conjunction with some embodiments of the seventh aspect, in some embodiments, the downlink signaling is MAC CE or RRC signaling, and the first information is not encrypted.

[0113] In conjunction with some embodiments of the seventh aspect, in some embodiments, the RRC connection recovery message is protected for security and integrity by a third security algorithm, which is determined based on predefined information.

[0114] In conjunction with some embodiments of the seventh aspect, in some embodiments, the transceiver module is further configured to receive second information broadcast by the first network device, the second information being used to indicate the security algorithm supported by the first network device, and the second information being used to trigger the terminal to send the first message.

[0115] In conjunction with some embodiments of the seventh aspect, in some embodiments, the security algorithm supported by the first network device does not include a first security algorithm, and the first message is an RRC connection establishment request message.

[0116] In conjunction with some embodiments of the seventh aspect, in some embodiments, the first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that the first security algorithm is not supported.

[0117] In conjunction with some embodiments of the seventh aspect, in some embodiments, the transceiver module is further configured to send an RRC connection establishment completion message to the first network device according to the RRC connection establishment message. The RRC connection establishment completion message includes fourth information, which is used to instruct the first network device to perform RRC reconfiguration according to the access layer context information of the terminal.

[0118] According to an eighth aspect of the present disclosure, a communication apparatus is provided, deployed on a second network device. The communication apparatus includes: a transceiver module, configured to receive a context request message sent by a first network device, the context request message including fifth information, the fifth information indicating a security algorithm supported by the first network device; and, based on the context request message, to send a context response message to the first network device, the context response message instructing the first network device to restore the RRC connection using a context-free approach, the context response message triggering the first network device to send an RRC connection restoration message to a terminal.

[0119] In conjunction with some embodiments of the eighth aspect, in some embodiments, the context response message includes sixth information, which indicates the tunnel endpoint assigned to the terminal, the tunnel endpoint being associated with a DRB one-to-one, and the RRC connection recovery message includes the sixth information.

[0120] In conjunction with some embodiments of the eighth aspect, in some embodiments, the context response message further includes seventh information, which is used to indicate context information for non-migrating terminals.

[0121] In conjunction with some embodiments of the eighth aspect, in some embodiments, the second network device is an anchor device of the first network device, and the second network device stores the context information of the terminal.

[0122] In a ninth aspect, embodiments of this disclosure provide a communication device, comprising: one or more processors, and one or more memories for storing a computer program; wherein the processor executes the computer program to implement the steps of the communication methods described in the first, second, and third aspects.

[0123] In a tenth aspect, embodiments of this disclosure provide a communication system including a first network device and a terminal, wherein the terminal is configured to send a first message to the first network device, the first message being used to request the establishment of an RRC connection with the first network device; the first network device is configured to send one of the following to the terminal: an RRC connection recovery message; an RRC connection establishment message, wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection.

[0124] In conjunction with some embodiments of the tenth aspect, in some embodiments, the first network device is further configured to send first information to the terminal, the first information being used to instruct the terminal to use a second security algorithm for security protection and integrity protection, the second security algorithm being different from the first security algorithm.

[0125] In conjunction with some embodiments of the tenth aspect, in some embodiments, the communication system further includes a second network device, wherein the first network device is further configured to send a context request message to the second network device according to a first message, the context request message being used to request context information of the terminal, and the first message being an RRC connection recovery request message; the second network device is configured to send the context information of the terminal to the first network device according to the context request message, the context information including a first security algorithm; the first network device is further configured to determine, based on the context information of the terminal, that the first network device does not support the first security algorithm.

[0126] In some embodiments of the tenth aspect, the first network device is further configured to use a third security algorithm to perform security and integrity protection on the RRC connection recovery message, the third security algorithm being determined based on predefined information.

[0127] In some embodiments of the tenth aspect, the first network device is further configured to broadcast second information, the second information being used to indicate a security algorithm supported by the first network device, and the second information being used to trigger a terminal to send a first message.

[0128] In some embodiments of the tenth aspect, the first network device is further configured to send a second message to the second network device, the second message being configured to instruct the second network device to release the context information of the terminal.

[0129] In some embodiments of the tenth aspect, the communication system further includes a second network device, wherein the second network device is configured to send an RRC connection establishment completion message to the first network device according to the RRC connection establishment message, the RRC connection establishment completion message including fourth information, the fourth information being used to instruct the first network device to perform RRC reconfiguration according to the access layer context information of the terminal.

[0130] In some embodiments of the tenth aspect, the communication system further includes a second network device, wherein the first network device is further configured to send context request information to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; the second network device is configured to send a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, and the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0131] Eleventhly, embodiments of this disclosure provide a communication system including a first network device and a second network device, wherein the first network device is configured to send a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithm supported by the first network device; the second network device is configured to send a context response message to the first network device according to the context request message, the context response message being used to instruct the first network device to restore the RRC connection using a context-free method, and the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0132] In a twelfth aspect, embodiments of this disclosure provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the communication method described in any of the first, second, and third aspects and their possible implementations.

[0133] In a thirteenth aspect, embodiments of this disclosure provide a computer program product, including a computer program that, when executed by a processor, implements the steps of the communication method described in any of the first, second, and third aspects and their possible implementations.

[0134] In a fourteenth aspect, embodiments of this disclosure provide a computer program comprising code that, when executed by a processor, implements the steps of the communication method described in any of the first, second, and third aspects and their possible implementations.

[0135] It is understood that the aforementioned communication equipment, communication system, storage medium, program product, etc., are all used to execute the methods proposed in the embodiments of this disclosure. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods, and will not be repeated here.

[0136] This disclosure provides a communication method, communication device, communication system, storage medium, and program product. In some embodiments, terms such as communication method, information processing method, and paging method can be used interchangeably; terms such as terminal, communication device, information processing device, information transmission device, network device, network function, and network entity can be used interchangeably; and terms such as communication system, information processing system, and information transmission system can be used interchangeably.

[0137] This disclosure is not exhaustive, but merely illustrative of some embodiments, and is not intended to limit the scope of protection of this disclosure. Unless otherwise specified, each step in a particular embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment can be arbitrarily interchanged. Furthermore, the optional implementation methods in a particular embodiment can be arbitrarily combined; moreover, the embodiments can be arbitrarily combined, for example, some or all steps of different embodiments can be arbitrarily combined, and a particular embodiment can be arbitrarily combined with the optional implementation methods of other embodiments. In all embodiments of this disclosure, unless otherwise specified or logically conflicting, the terminology and / or descriptions between the embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0138] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure.

[0139] In this embodiment of the disclosure, unless otherwise stated, elements expressed in the singular form, such as "a," "an," "the," "the," "the," "the," "the," "the," "this," etc., can mean "one and only one," or "one or more," "at least one," etc. For example, when using articles such as "a," "an," "the," etc. in translation, the noun following the article can be understood as either a singular expression or a plural expression.

[0140] In the embodiments disclosed herein, "multiple" refers to two or more.

[0141] In some embodiments, the terms “at least one of A or B, at least one of A and B”, “one or more”, “a plurality of”, “multiple”, etc., may be used interchangeably.

[0142] In some embodiments, the notation "at least one of A and B", "A and / or B", "A in one case, B in another", "in response to one case A, in response to another case B", etc., may include the following technical solutions depending on the situation: in some embodiments, A (execute A regardless of whether there is a branch B); in some embodiments, B (execute B regardless of whether there is a branch A); in some embodiments, execution is selected from A and B (A and B are selectively executed); in some embodiments, both A and B are executed. The same applies when there are more branches such as A, B, C, etc.

[0143] In some embodiments, the notation "A or B" may include the following technical solutions, depending on the situation: in some embodiments, A (execute A regardless of whether a branch B exists); in some embodiments, B (execute B regardless of whether a branch A exists); in some embodiments, execution is selected from A and B (A and B are selectively executed). The same applies when there are more branches such as A, B, and C.

[0144] The prefixes "first," "second," etc., used in the embodiments of this disclosure are merely for distinguishing different descriptive objects and do not impose restrictions on the position, order, priority, quantity, or content of the descriptive objects. The description of the descriptive objects is found in the claims or the context of the embodiments, and the use of prefixes should not constitute unnecessary restrictions. For example, if the descriptive object is a "field," the ordinal numbers preceding "field" in "first field" and "second field" do not restrict the position or order of the "fields." "First" and "second" do not restrict whether the "fields" they modify are in the same message, nor do they restrict the order of "first field" and "second field." Similarly, if the descriptive object is a "level," the ordinal numbers preceding "level" in "first level" and "second level" do not restrict the priority between "levels." Furthermore, the number of descriptive objects is not limited by ordinal numbers and can be one or more. For example, in "first device," the number of "devices" can be one or more. Furthermore, the objects modified by different prefixes can be the same or different. For example, if the object being described is "device", then "first device" and "second device" can be the same device or different devices, and their types can be the same or different. Similarly, if the object being described is "information", then "first information" and "second information" can be the same information or different information, and their content can be the same or different.

[0145] In some embodiments, “including A,” “containing A,” “for indicating A,” and “carrying A” can be interpreted as directly carrying A or indirectly indicating A.

[0146] In some embodiments, terms such as "time / frequency" and "time-frequency domain" refer to the time domain and / or frequency domain.

[0147] In some embodiments, "in response to...", "in response to determining...", "in the case of...", "when...", "when..."

[0148] Terms such as “when”, “if…”, and “if…” can be used interchangeably.

[0149] In some embodiments, the terms “greater than,” “greater than or equal to,” “not less than,” “more than,” “more than or equal to,” “not less than,” “higher than,” “higher than or equal to,” “not lower than,” and “above” can be used interchangeably, as can the terms “less than,” “less than or equal to,” “not greater than,” “less than,” “less than or equal to,” “not more than,” “lower than,” “lower than or equal to,” “not higher than,” and “below”.

[0150] In some embodiments, devices, etc., can be interpreted as physical or virtual, and their names are not limited to the names recorded in the embodiments. Terms such as “device”, “equipment”, “circuit”, “network element”, “node”, “function”, “unit”, “section”, “system”, “network”, “chip”, “chip system”, “entity”, and “subject” can be used interchangeably.

[0151] In some embodiments, "network" can be interpreted as devices included in a network (e.g., access network devices, core network devices, etc.).

[0152] In some embodiments, the terms "access network device (AN device)," "radio access network device (RAN device)," "base station (BS)," "radio base station," "fixed station," "node," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "antenna panel," "antenna array," "cell," "macro cell," "small cell," "femto cell," "pico cell," "sector," "cell group," "serving cell," "carrier," "component carrier," and "bandwidth part (BWP)" can be used interchangeably.

[0153] In some embodiments, the terms "terminal", "terminal device", "user equipment (UE)", "user terminal", "mobile station (MS)", "mobile terminal (MT)", "subscriber station", "mobile unit", "subscriber unit", "wireless unit", "remote unit", "mobile device", "wireless device", "wireless communication device", "remote device", "mobile subscriber station", "access terminal", "mobile terminal", "wireless terminal", "remote terminal", "handset", "user agent", "mobile client", and "client" can be used interchangeably.

[0154] In some embodiments, access network devices, core network devices, or network devices can be replaced by terminals. For example, embodiments of this disclosure can also be applied to structures where communication between access network devices, core network devices, or network devices and terminals is replaced by communication between multiple terminals (e.g., device-to-device (D2D), vehicle-to-everything (V2X), etc.). In this case, the structure can also be configured such that the terminal has all or part of the functions of the access network device. Furthermore, terms such as "uplink" and "downlink" can be replaced with terms corresponding to communication between terminals (e.g., "sidelink"). For example, uplink channel, downlink channel, etc., can be replaced with sidelink channel, and uplink link, downlink, etc., can be replaced with sidelink link.

[0155] In some embodiments, the terminal may be replaced by an access network device, a core network device, or a network device. In this case, the access network device, core network device, or network device may also be configured to have all or some of the functions of the terminal.

[0156] In some embodiments, the acquisition of data, information, etc., may comply with the laws and regulations of the country where the location is situated.

[0157] In some embodiments, data, information, etc., may be obtained with the user's consent.

[0158] Furthermore, each element, each row, or each column in the table of this disclosure can be implemented as an independent embodiment, and any combination of any element, any row, or any column can also be implemented as an independent embodiment.

[0159] Figure 1A is a schematic diagram of the architecture of a communication system according to an embodiment of the present disclosure. As shown in Figure 1A, the communication system 100 includes at least one of a terminal 101, an access network device 102, and a core network device 103.

[0160] In some embodiments, terminal 101 includes, but is not limited to, at least one of the following: mobile phone, wearable device, Internet of Things device, car with communication function, smart car, tablet computer, computer with wireless transceiver function, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal device in industrial control, wireless terminal device in self-driving, wireless terminal device in remote medical surgery, wireless terminal device in smart grid, wireless terminal device in transportation safety, wireless terminal device in smart city, and wireless terminal device in smart home.

[0161] In some embodiments, the access network device 102, such as a node or device for connecting a terminal to a wireless network, may include at least one of, but is not limited to, an evolved node B (eNB), a next-generation eNB (ng-eNB), a next-generation node B (gNB), a node B (NB), a home node B (HNB), a home evolved node B (HeNB), a wireless backhaul device, a radio network controller (RNC), a base station controller (BSC), a base transceiver station (BTS), a base band unit (BBU), a mobile switching center, a base station in a 6G communication system, an open RAN, a cloud RAN, a base station in other communication systems, and an access node in a Wi-Fi system.

[0162] In some embodiments, the technical solutions of this disclosure can be applied to Open Radio Access Network (Open RAN) architectures. In this case, the interfaces between or within access network devices involved in the embodiments of this disclosure can be transformed into internal interfaces of Open RAN. The processes and information interactions between these internal interfaces can be implemented by software or programs.

[0163] In some embodiments, the access network device may be composed of a central unit (CU) and a distributed unit (DU). The CU may also be called a control unit. The CU-DU structure can separate the protocol layer of the access network device. Some of the protocol layer functions are centrally controlled by the CU, while the remaining part or all of the protocol layer functions are distributed in the DU and centrally controlled by the CU. However, this is not the only possibility.

[0164] In some embodiments, the core network device 103 may be a single device comprising one or more network elements, or it may be multiple devices or a group of devices, each comprising all or part of one or more network elements. Network elements may be virtual or physical. The core network may include, for example, at least one of an evolved packet core (EPC) network, a 5G core (5GC) network, and a next-generation core (NGC) network.

[0165] It is understood that the communication system described in this disclosure is for the purpose of more clearly illustrating the technical solutions of this disclosure, and does not constitute a limitation on the technical solutions proposed in this disclosure. As those skilled in the art will know, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions proposed in this disclosure are also applicable to similar technical problems.

[0166] The following embodiments of this disclosure can be applied to the communication system 100 shown in FIG1A, or some of the main components in the communication system 100, but are not limited thereto. The main components shown in FIG1A are illustrative. The communication system 100 may include all or some of the main components in FIG1A, or may include other main components other than those in FIG1A. The number and form of each main component are arbitrary. Each main component may be physical or virtual. The connection relationship between the main components is illustrative. The main components may not be connected or may be connected. The connection may be in any way, such as direct connection or indirect connection, wired connection or wireless connection.

[0167] The embodiments disclosed herein can be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), Super 3G, International Mobile Telecommunications-Advanced (IMT-Advanced), 4th Generation Mobile Communication System (4G), 5th Generation Mobile Communication System (5G), 5G New Radio (NR), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New Radio Access (NX), Future Generation Radio Access (FX), Global System for Mobile Communications (GSM), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20, ultra-wideband (UWB), Bluetooth (a registered trademark), public land mobile network (PLMN) networks, device-to-device (D2D) systems, machine-to-machine (M2M) systems, internet of things (IoT) systems, vehicle-to-everything (V2X) systems, systems utilizing other communication methods, and next-generation systems built upon them. Furthermore, multiple systems can be combined (e.g., a combination of LTE or LTE-A with 5G).

[0168] In some embodiments, in a 5G network environment, to reduce air interface signaling and quickly restore data services for wireless connections, a new RRC connection state, namely the RRC inactive state (RRC_INACTIVE), is introduced. This state is different from the RRC idle state (RRC_IDLE) and the RRC connected state (RRC_CONNECTED).

[0169] In some embodiments, RRC_IDLE is an access layer state in which a terminal (such as a UE) is camped on a cell but has not established any RRC connection. The UE will enter the RRC_IDLE state when it is disconnected from the network or is in an unregistered state.

[0170] In some embodiments, RRC_CONNECTED indicates that an RRC connection has been established between the UE and the network. The UE enters the RRC_CONNECTED state when it needs to transmit data or is in an active state.

[0171] In some embodiments, RRC_INACTIVE indicates that the UE is connected to the network, but the UE is in an inactive state. When the UE is inactive for a certain period of time, the connection will change from the RRC_CONNECTED state to the RRC_INACTIVE state to save terminal power consumption and reduce signaling load.

[0172] In some embodiments, the characteristics of the RRC_INACTIVE state include: (1) the connection between the RAN and CN is maintained; (2) the UE (e.g., a terminal or IoT device) and at least one gNB retain the access layer context; (3) the UE is reachable from the RAN side, and the relevant parameters are configured by the RAN; (4) when the UE moves within the RAN-based notification area (RNA), it does not need to notify the network side, but when it moves out of the RNA, it needs to notify the network side; (5) the UE moves within the RNA according to the cell selection reselection method; and (6) there are Xn links between gNBs within the RNA.

[0173] In some embodiments, the RAN configures configuration parameters for the RRC state, which may include configuration parameters regarding RRC state transitions, such as configuration information required to transition the UE from the RRC_CONNECTED state to the RRC_INACTIVE state. These configuration parameters allow the UE to enter a low-power RRC_INACTIVE state when data transmission is not required, while maintaining connectivity with the core network, so that the RRC connection can be quickly restored when needed.

[0174] In some embodiments, the configuration parameters of RRC_INACTIVE can be configured through the RRC_Release message and may include one or more of the following: SuspendConfig, device identifier (such as I-RNTI), RNA, RAN discontinuous reception (DRX) period, RAN-based notification area update (RNAU) periodicity configuration, and Next-Hop chaining counter (NCC).

[0175] In some embodiments, SuspendConfig represents configuration information for the RRC_INACTIVE state, including the UE's state in...

[0176] Configuration information that needs to be retained in the RRC_INACTIVE state, such as context information and timer settings.

[0177] In some embodiments, the I-RNTI is a unique identifier for the device (anchor base station) that stores the UE's context information. The I-RNTI may include: I-RNTI (40 bits) and short I-RNTI (24 bits).

[0178] In some embodiments, RNA may include: a list of cells, a list of RAN Area IDs, and a list of TAIs.

[0179] It should be noted that the RAN area code is broadcast in the cell's system broadcast. The RAN area is larger than the cell, but smaller than the Tracking Area (TA). For example, the RAN area code is 8 bits, indicating that there are a maximum of 255 RAN areas within a TA.

[0180] It's important to note that the TAI list contains information on all TAIs within the network, which is crucial for location and mobility management. When a UE moves between different TAIs, a Tracking Area Update (TAU) procedure needs to be performed to notify the network of its current location. Maintaining the TAI list helps ensure that the network can accurately track the UE's location and provide necessary services.

[0181] In some embodiments, the RAN DRX period is used to calculate the paging frame (PF) or paging opportunity (PO) of the initial paging message in the RAN. The DRX period is selected for PF or PO calculation based on the minimum value among the cell default DRX period, UE specific DRX period, and RAN DRX period.

[0182] In some embodiments, the periodic configuration of RNAU can be used to control periodic RNAU.

[0183] In some embodiments, NCC is used as the key for message 4 (e.g., MSG4) during the RRC connection resume process. During the RRC resume process, the key for MSG4 can be encrypted or verified using the NCC algorithm. By calculating the normalized cross-correlation coefficient of the two sequences, NCC can assess their similarity, thereby ensuring the integrity and security of MSG4.

[0184] In some embodiments, the UE transitions from the RRC_INACTIVE state to the RRC_CONNECTED state using the RRC connection recovery process in NR, as follows:

[0185] (1) Triggering reason

[0186] In some embodiments, for a UE in the RRC_INACTIVE state, this process is triggered when uplink data arrives, the periodic RNAU timer times out, or an initial RAN paging is received.

[0187] (2) RRC connection restored to RRC_CONNECTED

[0188] Figure 1B is an interactive schematic diagram of an exemplary communication method provided according to an embodiment of the present disclosure. As shown in Figure 1B, the RRC connection recovery process includes:

[0189] In step S101, the UE is in an RRC inactive state, and it is determined that the RRC connection needs to be restored.

[0190] In some embodiments, the UE is in an RRC inactive state and can camp on a cell provided by the serving base station. In one embodiment, the serving base station can be understood as the base station that provides the UE with the cell to camp on.

[0191] In step S102, the UE sends message 1 (MSG1) to the serving base station. In some embodiments, message 1 includes a random access preamble. In one example, the UE can obtain physical random access channel (PRACH) configuration information from system messages (e.g., SIB1) and send the random access preamble through the PRACH channel. In one example, the configuration information includes the length of the preamble sequence, time-domain resources, and other information.

[0192] In some embodiments, the UE may select a preamble sequence and transmit the preamble sequence to the serving base station on the PRACH channel.

[0193] It should be noted that the term "message" in the embodiments of this disclosure can be replaced by terms such as "information," "signaling," "signaling," and "command." Of course, it can also refer to other transmission forms sent by network devices to terminals to perform certain operations on terminal devices. The embodiments of this disclosure do not specifically limit this.

[0194] In step S103, the serving base station sends message 2 (MSG2) to the UE according to message 1.

[0195] In some embodiments, message 2 may be a random access response (RAR) message.

[0196] In some embodiments, after detecting a preamble sequence, the serving base station sends a RAR response message as message 1 to the UE. In one embodiment, the RAR message may include timing adjustment information, uplink resource allocation information, and other information.

[0197] In step S104, the UE sends message 3 (MSG3) to the serving base station.

[0198] In some embodiments, message 3 may be an RRC Connection Resume Request (RRC Resume Request) message.

[0199] In some embodiments, the UE transmits the following message via the uplink common control channel (UL_CCCH) on Signaling Radio Bearers (SRB) 0: the UE's initial access stratum (AS) identification information, ShortMAC-I, and recovery reason. This message corresponds to MSG3 in the random access procedure. After sending this message, the UE activates security, generates a key, and resumes SRB1 waiting to receive message 4 (MSG4).

[0200] In step S105, the serving base station obtains the UE context message stored on the anchor base station.

[0201] In some embodiments, the anchor base station stores the UE's context information.

[0202] In some embodiments, when the UE is in the RRC_INACTIVE state, the context information stored by the UE and the anchor base station includes: security context information, AS context information, and partial non-access stratum (NAS) context information. The security context information is used to protect the security of communication between the UE and network devices. The AS context information is used to manage the configuration and state of the radio access stratum. The NAS context information is used to manage communication between the UE and the core network.

[0203] In one embodiment, the security context information may include information such as a security algorithm, encryption key, integrity protection key, and security configuration parameters. The security algorithm is used for both security and integrity protection. This security algorithm is the one used by the UE before entering the RRC inactive state.

[0204] In one embodiment, AS context information may include radio bearer configuration, radio resource management information, radio protocol status, cell-related information, etc. In one example, the radio bearer may include DRB and SRB.

[0205] In some embodiments, the serving base station may send a context request message to the anchor base station to obtain the UE's context information. Upon receiving the context request message, the anchor base station sends the UE's context information to the serving base station.

[0206] In step S106, the serving base station sends message 4 (MSG4) to the UE.

[0207] In some embodiments, message 4 may be an RRC Connection Resume or RRC Resume message.

[0208] In some embodiments, the serving base station transmits this message on SRB1 via the downlink dedicated control channel (DL_DCCH), which corresponds to MSG4 of the random access procedure. MSG4 provides security and integrity protection.

[0209] In step S107, the UE enters the RRC connection state.

[0210] In step S108, the UE sends message 5 (MSG5) to the serving base station.

[0211] In some embodiments, message 5 may be an RRC Connection Resume Complete (RRC Connection Resume Complete) message.

[0212] In some embodiments, the UE transmits on SRB1 via the uplink dedicated control channel (UL-DCCH) without carrying any actual information, serving as an RRC layer acknowledgment function.

[0213] At this point, the UE transitions from the RRC inactive state to the RRC connected state.

[0214] In one example, Figure 1C is an interactive schematic diagram of an exemplary communication method provided according to an embodiment of the present disclosure. As shown in Figure 1C, the RRC connection recovery process includes:

[0215] In step S111, the UE sends an RRC connection restoration request message to the network (such as the serving base station).

[0216] In step S112, the network sends an RRC connection restoration message to the UE.

[0217] In step S113, the UE sends an RRC connection restoration complete message to the network.

[0218] (3) RRC connection restored to RRC_INACTIVE

[0219] In some embodiments, if the serving base station decides to release the UE to the RRC_INACTIVE state (e.g., periodic RNAU) after receiving the RRC connection restoration request message, the serving base station carries an RRC release message in message 4, which is used to update the INACTIVE configuration parameters.

[0220] In one example, as shown in Figure 1D, the RRC connection recovery process includes:

[0221] In step S121, the UE sends an RRC connection restoration request message to the network (such as the serving base station);

[0222] In step S122, the network sends an RRC release message to the UE, which carries the suspend configuration (RRCRelease with suspend configuration).

[0223] (4) RRC connection restored to RRC_IDLE

[0224] In some embodiments, if the serving base station decides to release the UE to the RRC_IDLE state after receiving the RRC connection restoration request message, the serving base station carries the RRCRelease message in message 4.

[0225] In one example, Figure 1E is an interactive schematic diagram of an exemplary communication method provided according to an embodiment of the present disclosure. As shown in Figure 1E, the RRC connection recovery process includes:

[0226] In step S131, the UE sends an RRC connection restoration request message to the network (such as the serving base station);

[0227] In step S132, the network sends an RRC release message to the UE.

[0228] (5) RRC connection recovery failed

[0229] In some embodiments, if at least one of the following occurs: the first timer (e.g., T319) for the RRC connection recovery request times out, the integrity protection verification of the RRC connection recovery message (MSG4) fails, or cell reselection occurs during the operation of the second timer (e.g., T310), then the RRC connection reconstruction fails for the above reasons, and the UE returns to the RRC_IDLE state.

[0230] In some embodiments, if there is no UE context information in the network (such as the serving base station), an RRC connection re-establishment (or RRC connection establishment) message is sent on SRB0 via the downlink common control channel (DL_CCCH). Upon receiving this message, the UE deletes the previous context and performs the RRC connection re-establishment process.

[0231] In one example, Figure 1F is an interactive schematic diagram of an exemplary communication method provided according to an embodiment of the present disclosure. As shown in Figure 1F, the RRC connection recovery process includes:

[0232] In step S141, the UE sends an RRC connection restoration request to the network (such as the serving base station);

[0233] In step S142, if there is no UE context information in the network, an RRC connection establishment (RRC Setup) message is sent on SRB0 via DL_CCCH;

[0234] In step S143, the UE establishes an RRC connection and sends an RRC Setup Complete message to the network.

[0235] In some embodiments, the UE receives an RRC connection rejection (RRCReject) message, for example, due to network load control reasons. At this time, the UE returns to the initial RRC_INACTIVE state.

[0236] In one example, Figure 1G is an interactive schematic diagram of an exemplary communication method provided according to an embodiment of the present disclosure. As shown in Figure 1G, the RRC connection recovery process includes:

[0237] In step S151, the UE sends an RRC connection restoration request message to the network (such as the serving base station);

[0238] In step S152, the network sends an RRCReject message to the UE for reasons such as load control.

[0239] At this point, the UE returns to its initial RRC_INACTIVE state.

[0240] It should be noted that both the RRC connection establishment and recovery processes require context information existing on the network side to restore the RRC connection and services. The RRC connection establishment process focuses on restoring the RRC connection, requiring an RRC connection reconfiguration message to configure the bearer. The RRC connection recovery process focuses on restoring the RRC connection and service bearer, therefore it has shorter latency. Furthermore, the RRC connection recovery process offers better security.

[0241] In some embodiments, if the serving base station determines, after receiving the UE's context information, that it does not support the security algorithm used by the UE before entering the RRC inactive state, the serving base station instructs the UE to fall back. This increases the RRC connection latency and also negates the advantage of the UE quickly resuming the RRC connection in the RRC inactive state.

[0242] To address the aforementioned issues, embodiments of this disclosure provide a communication method, communication device, communication system, storage medium, and program product to reduce RRC connection latency, improve RRC connection efficiency, thereby enabling rapid data transmission and reception, and enhancing the robustness of terminal mobility.

[0243] Figure 2A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 2A, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system 100. In one example, the aforementioned communication method includes steps S2101 to S2104.

[0244] In some embodiments, the communication system 100 described above may include a first network device. In one embodiment, the first network device is an access network device. In one embodiment, a terminal accesses the network through the first network device. In one example, the first network device is a base station.

[0245] In step S2101, the first network device broadcasts the second information.

[0246] In some embodiments, the first network device may periodically broadcast second information. In one embodiment, the first network device broadcasts the second information via a physical broadcast channel (PBCH).

[0247] In some embodiments, the terminal may periodically receive second information.

[0248] In some embodiments, the terminal is in an RRC inactive state. In this state, the terminal receives second information to determine whether to perform cell reselection.

[0249] In some embodiments, the second information is used to indicate the security algorithms supported by the first network device. In one embodiment, the security algorithm is used for integrity protection and security protection. In one embodiment, the security algorithm includes an integrity protection algorithm and an encryption algorithm, wherein the integrity protection algorithm is used to ensure that the signaling message is not tampered with during transmission. The encryption algorithm is used to protect the confidentiality of the signaling message content and prevent unauthorized eavesdropping. In one example, the integrity protection algorithm includes algorithms such as Advanced Encryption Standard-Message Authentication Code (AES-CMAC) and Hash-based Message Authentication Code-Secure Hash Algorithm 256-bit (HMAC-SHA256). In one example, the encryption algorithm includes algorithms such as Advanced Encryption Standard 128-bit (AES-128) and Advanced Encryption Standard 256-bit (AES-256).

[0250] In some embodiments, the first network device may carry a field in the broadcast second information that can be used to indicate the security algorithms supported by the first network device.

[0251] In some embodiments, the field carried by the second information may be an identifier of the security algorithm. In this case, the field may also be a first algorithm identifier (ID). In one embodiment, the first algorithm identifier is used to uniquely identify the security algorithm supported by the first network device. In one embodiment, the security algorithm supported by the first network device may include at least one of an integrity protection algorithm and an encryption algorithm. In this case, the field carried by the second information may include at least one of a first integrity protection algorithm identifier and a first encryption algorithm identifier. The first integrity protection algorithm identifier is used to uniquely identify the integrity protection algorithm supported by the first network device, and the first encryption algorithm identifier is used to uniquely identify the encryption algorithm supported by the first network device.

[0252] In one example, the first integrity protection algorithm identifier can be an algorithm identifier such as 128-NIA1 (Snow 3G-based integrity protection algorithm), 128-NIA2 (AES-based integrity protection algorithm), or 128-NIA3 (ZUC-based integrity protection algorithm).

[0253] In one example, the first encryption algorithm identifier can be an algorithm identifier such as 128-NEA1 (encryption algorithm based on Snow 3G), 128-NEA2 (encryption algorithm based on AES), 128-NEA3 (encryption algorithm based on ZUC), etc.

[0254] In some embodiments, the fields carried by the second information may include one or more parameters, which may be parameters associated with a security algorithm to indicate the security algorithm supported by the first network device. In one embodiment, these parameters may include parameters such as algorithm type, key length, and algorithm version.

[0255] In one example, if the parameters carried in the second information include: the algorithm type is an encryption algorithm and the key length is 128 bits, it can be determined that the security algorithm supported by the first network device is AES-128.

[0256] In some embodiments, the first network device may support one or more security algorithms. In one example, the second information may be a list of security algorithms.

[0257] In step S2102, the terminal determines whether the security algorithm supported by the first network device includes the first security algorithm.

[0258] In some embodiments, when a terminal is in an RRC inactive state, it can select a cell to camp on in order to restore the RRC connection on that cell. In one embodiment, when a terminal in an RRC inactive state has uplink data to send, it selects a cell to camp on. In another embodiment, when a terminal in an RRC inactive state receives a paging message from the network side and determines to respond to the paging message, it selects a cell to camp on. In yet another embodiment, when a terminal in an RRC inactive state experiences a tracking area update, it selects a cell to camp on. Of course, the terminal can also select a cell to camp on in other situations, and this disclosure does not specifically limit this.

[0259] In some embodiments, the terminal may select a cell to camp on. In one embodiment, the cell may be a cell that the terminal accessed before entering the RRC inactive state, a new cell that the terminal reselected, or the cell that the terminal is currently in. Of course, the cell may also be other types, and this disclosure does not specifically limit this.

[0260] In some embodiments, the aforementioned cell is provided by a first network device. In one embodiment, after the terminal camps on a cell provided by the first network device, the terminal can listen to and receive system information broadcast by the first network device, the system information including second information.

[0261] In some embodiments, the first security algorithm is the security algorithm used by the terminal before entering the RRC inactive state, i.e., when the terminal was last in the connected state. Therefore, the terminal can preferentially select a cell that supports the first security algorithm to camp on based on the second information. If none of the cells support the first security algorithm, the terminal can choose any cell to camp on.

[0262] In some embodiments, step S2102 can also be described as: the terminal determines whether the security algorithm supported by the first network device includes the security algorithm it used before entering the RRC inactive state, the terminal determines whether the first network device supports the security algorithm it used before entering the RRC inactive state, and the terminal determines whether the first network device supports the first security algorithm.

[0263] In some embodiments, after step S2101, the terminal receives second information and determines, based on the second information, whether the security algorithm supported by the first network device includes the first security algorithm. In some embodiments, the terminal can determine, based on the second information, whether the security algorithm supported by the first network device includes the security algorithm it used before entering the RRC inactive state. In one embodiment, the terminal can determine, based on the second information, whether the first network device supports the security algorithm it used before entering the RRC inactive state. In one embodiment, the terminal can determine, based on the second information, whether the first network device supports the first security algorithm.

[0264] In some embodiments, when the terminal is in an RRC inactive state, the terminal locally stores its own context information. In one embodiment, the context information includes at least one of the following: security context information, AS context information, and partial NAS context information.

[0265] In one embodiment, the security context information includes information such as the security algorithm, encryption key, integrity protection key, and security configuration parameters. In one example, the security algorithm is the first security algorithm used by the terminal before entering the RRC inactive state.

[0266] In one embodiment, the AS context information includes radio bearer configuration, radio resource management information, radio protocol status, cell-related information, etc. In one example, the radio bearer may include DRB and SRB.

[0267] In one embodiment, the NAS context information includes information such as the terminal's identifier and some mobility information.

[0268] In some embodiments, after receiving the second information, the terminal can match the security algorithm supported by the first network device included in the second information with the stored first security algorithm to determine whether the security algorithm supported by the first network device includes the first security algorithm, and then determine whether to trigger the RRC connection establishment process or the RRC connection recovery process.

[0269] In some embodiments, when the first network device supports multiple security algorithms, the terminal can match each of the multiple security algorithms with the first security algorithm one by one. If the first security algorithm matches one of the multiple security algorithms, the terminal can determine that the multiple security algorithms include the first security algorithm, and in this case, the first network device supports the first security algorithm used by the terminal. If the first security algorithm does not match any of the multiple security algorithms, the terminal can determine that the multiple security algorithms do not include the first security algorithm, and in this case, the first network device does not support the first security algorithm used by the terminal.

[0270] In some embodiments, if the first network device supports a security algorithm, the terminal can match the security algorithm with a first security algorithm. If they match, the terminal can determine that the first network device supports the first security algorithm used by the terminal. If they do not match, the terminal can determine that the first network device does not support the first security algorithm used by the terminal.

[0271] In some embodiments, if the security algorithm supported by the first network device does not include the first security algorithm, step S2103 is executed (see solid line in 2A); if the security algorithm supported by the first network device includes the first security algorithm, step S2104 is executed (see dashed line in 2A).

[0272] In step S2103, the terminal and the first network device perform an RRC connection establishment process.

[0273] In some embodiments, if the terminal determines that the first network device does not support the first security algorithm, it falls back to an idle state and initiates an RRC connection establishment process. In one embodiment, during the RRC connection establishment process, the terminal sends an RRC connection establishment request message to the first network device. The first network device responds to the RRC connection establishment request message by sending an RRC connection establishment message to the terminal. The terminal then sends an RRC connection establishment complete message to the first network device based on the RRC connection establishment message.

[0274] In some embodiments, the RRC connection establishment request message is the first message. In one example, the RRC connection establishment request message can be an RRC Connection Setup Request message or an RRC Setup Request message.

[0275] In some embodiments, if the first network device does not support a first security algorithm, the terminal determines that the first network device does not support the first security algorithm used by the terminal. In this case, the terminal can perform a fallback. In one embodiment, during the fallback process, the terminal can transition from an RRC inactive state to an RRC idle state, and then trigger an RRC connection establishment process, i.e., the terminal sends an RRC connection establishment request message to the first network device while in the idle state. In this way, through the RRC connection establishment process, the terminal can negotiate a new security algorithm with the first network device, thereby optimizing network resource utilization.

[0276] In one example, the RRC connection setup complete message can be either an RRC Connection Setup Complete message or an RRC Setup Complete message.

[0277] In some embodiments, after the RRC connection is established, the terminal is in the RRC connected state. At this time, the first network device can update the terminal's configuration information according to the network requirements and changes in the terminal's state.

[0278] In some embodiments, the RRC connection establishment completion message may include fourth information, which instructs the first network device to perform RRC reconfiguration based on the terminal's AS context information.

[0279] In some embodiments, after the terminal sends an RRC connection establishment complete message, the first network device can reconfigure the terminal's context information. If the RRC connection establishment complete message includes fourth information, the first network device can directly use the terminal's AS context information in the RRC inactive state according to the instructions of the fourth information, without needing to reconfigure the AS context information. That is, the first network device does not need to configure all the context information for the terminal, thereby reducing signaling overhead and improving configuration efficiency.

[0280] In step S2104, the terminal and the first network device perform an RRC connection restoration process.

[0281] In some embodiments, if the terminal determines that the first network device supports the first security algorithm, it initiates an RRC connection recovery process. In one embodiment, during the RRC connection recovery process, the terminal sends an RRC connection recovery request message to the first network device. The first network device responds to the RRC connection recovery request message by sending an RRC connection recovery message to the terminal. The terminal then sends an RRC connection recovery complete message to the first network device based on the RRC connection recovery message.

[0282] In some embodiments, the RRC connection recovery request message is the first message. In one example, the RRC connection recovery request message can be an RRC Connection Resume Request message or an RRC Resume Request message.

[0283] In some embodiments, where the first network device supports a security algorithm including a first security algorithm, the terminal determines that the first network device supports the first security algorithm used by the terminal. In this case, the terminal can trigger an RRC connection recovery process, that is, the terminal sends an RRC connection recovery request message to the first network device while in an inactive state. In this way, the terminal can quickly restore the RRC connection and enter the connected state through the RRC connection recovery process.

[0284] In some embodiments, the RRC connection recovery request message carries an I-RNTI, which identifies the base station storing the terminal's context information in the RRC inactive state. Thus, the first network device can obtain the terminal's context information based on the I-RNTI and send an RRC connection recovery message to the terminal. The terminal then recovers its context information based on the RRC connection recovery message. Afterward, an RRC connection recovery completion message is sent to the first network device to complete the RRC connection recovery process.

[0285] In some embodiments, the terminal may send an RRC connection restoration request message to the first network device on SRB0 via the UL uplink common control channel (UL_CCCH).

[0286] This completes the process of establishing an RRC connection between the terminal and the first network device. Here, "establish" can be understood as "new", "rebuild", or "restore".

[0287] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0288] Figure 2B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 2B, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the aforementioned communication method includes steps S2201 to S2204.

[0289] In some embodiments, the communication system 100 may further include a first network device. In one embodiment, the first network device is an access network device. In one embodiment, a terminal accesses the network through the first network device. In one example, the first network device is a base station.

[0290] In step S2201, the terminal sends an RRC connection recovery request message to the first network device.

[0291] In some embodiments, the terminal sends an RRC connection restoration request message. In some embodiments, the RRC connection restoration request message may be sent by the terminal, but is not limited to this, and may also be sent by other entities.

[0292] In some embodiments, the first network device receives an RRC connection restoration request message. In some embodiments, the RRC connection restoration request message may be received by the first network device, but is not limited to this; it may also be received by other entities.

[0293] In some embodiments, when a terminal is in an RRC inactive state, it can select a cell to camp on in order to restore the RRC connection on that cell. In one embodiment, when a terminal in an RRC inactive state has uplink data to send, it selects a cell to camp on. In another embodiment, when a terminal in an RRC inactive state receives a paging message from the network side and determines to respond to the paging message, it selects a cell to camp on. In yet another embodiment, when a terminal in an RRC inactive state experiences a tracking area update, it selects a cell to camp on. Of course, the terminal can also select a cell to camp on in other situations, and this disclosure does not specifically limit this.

[0294] In some embodiments, the terminal may select a cell to camp on. In one embodiment, the cell may be a cell that the terminal accessed before entering the RRC inactive state, a new cell that the terminal reselected, or the cell that the terminal is currently in. Of course, the cell may also be other types, and this disclosure does not specifically limit this.

[0295] In some embodiments, the aforementioned cell is provided by a first network device.

[0296] In some embodiments, after the terminal camps on a cell, it can send an RRC connection restoration request message on that cell.

[0297] In some embodiments, the RRC connection recovery request message is the first message. In one example, the RRC connection recovery request message can be an RRC Connection Resume Request message or an RRC Resume Request message.

[0298] In some embodiments, a terminal in an RRC inactive state camps on a cell provided by a first network device. When the terminal initiates a RAN location area update, it sends an RRC connection restoration request message to the first network device to restore the RRC connection. In one embodiment, the terminal sends an RRC connection restoration request message to the first network device when periodically initiating a RAN location update. In another embodiment, the terminal sends an RRC connection restoration request message to the first network device when initiating a tracking area update.

[0299] In some embodiments, the RRC connection restoration request message may include third information, which indicates the security algorithm used by the terminal before entering the RRC inactive state, namely a first security algorithm. In one embodiment, the first security algorithm is used for integrity protection and security protection.

[0300] In some embodiments, the terminal may carry a field in the third information that can be used to indicate the first security algorithm.

[0301] In some embodiments, the field carried by the third information can be an identifier of the security algorithm. In this case, the field can also be a second algorithm identifier (ID). In one embodiment, the second algorithm identifier is used to uniquely identify the first security algorithm. In one embodiment, the first security algorithm may include at least one of an integrity protection algorithm and an encryption algorithm. In this case, the field carried by the third information may include at least one of a second integrity protection algorithm identifier and a second encryption algorithm identifier. Specifically, the second integrity protection algorithm identifier is used to uniquely identify the integrity protection algorithm used by the terminal before entering the RRC inactive state, and the second encryption algorithm identifier is used to uniquely identify the encryption algorithm used by the terminal before entering the RRC inactive state.

[0302] In one example, the second integrity protection algorithm identifier can be an algorithm identifier such as 128-NIA1 (Snow 3G-based integrity protection algorithm), 128-NIA2 (AES-based integrity protection algorithm), or 128-NIA3 (ZUC-based integrity protection algorithm).

[0303] In one example, the second encryption algorithm identifier can be an algorithm identifier such as 128-NEA1 (encryption algorithm based on Snow 3G), 128-NEA2 (encryption algorithm based on AES), or 128-NEA3 (encryption algorithm based on ZUC).

[0304] In some embodiments, the fields carried by the third information may include one or more parameters, which may be parameters associated with a security algorithm to indicate the security algorithm used by the terminal before entering the RRC inactive state. In one embodiment, these parameters may include parameters such as algorithm type, key length, and algorithm version.

[0305] In one example, if the parameters carried by the third information include: the algorithm type is an encryption algorithm and the key length is 128 bits, it can be determined that the security algorithm supported by the first network device is AES-128.

[0306] In some embodiments, the RRC connection recovery request message may include eighth information, which is used to indicate the device storing the context information of the terminal in the anchor access network device.

[0307] In some embodiments, the eighth information carries the device identifier of the device storing the context information of the terminal, such as I-RNTI.

[0308] In some embodiments, the first message includes at least one of a third message and an eighth message. The third message indicates the security algorithm used by the terminal before entering the RRC inactive state, and the eighth message indicates the device storing the terminal's context information.

[0309] In step S2202, the first network device determines that it does not support the first security algorithm.

[0310] In some embodiments, after receiving an RRC connection restoration request message, the first network device determines, based on third information, the first security algorithm used by the terminal before entering the RRC inactive state, and matches its own supported security algorithms with the first security algorithm used by the terminal to determine whether the first network device supports the first security algorithm used by the terminal.

[0311] In some embodiments, when the first network device supports multiple security algorithms, the first network device can match each of the supported security algorithms with the first security algorithm one by one. If the first security algorithm matches one of the multiple security algorithms, that is, the first security algorithm is included among the multiple security algorithms, then the first network device can determine that it supports the first security algorithm. If the first security algorithm does not match any of the multiple security algorithms, that is, the first security algorithm is not included among the multiple security algorithms, then the first network device can determine that it does not support the first security algorithm.

[0312] In some embodiments, if the first network device supports a security algorithm, the first network device may match the supported security algorithm with the first security algorithm. If they match, the first network device may determine that it supports the first security algorithm. If they do not match, the first network device may determine that it supports the first security algorithm.

[0313] In some embodiments, if the first network device determines that it supports the first security algorithm, it can use the first security algorithm to protect the RRC connection recovery message before sending it to the terminal. Thus, after receiving the RRC connection recovery message, the terminal can use the first security algorithm to decode it to obtain the radio bearer configuration, and after completing the RRC connection recovery, send an RRC connection recovery completion message to the first network device.

[0314] In step S2203, the first network device sends an RRC connection establishment message to the terminal.

[0315] In some embodiments, the first network device sends an RRC connection establishment message. In some embodiments, the RRC connection establishment message may be sent by the first network device, but is not limited thereto, and may also be sent by other entities.

[0316] In some embodiments, the terminal receives an RRC connection establishment message. In some embodiments, the RRC connection establishment message may be received by the terminal, but is not limited to this; it may also be received by other entities.

[0317] In one example, the RRC connection establishment message can be either an RRC Connection Setup message or an RRC Setup message.

[0318] In some embodiments, if the first network device determines that it does not support the first security algorithm, the first network device may send an RRC connection establishment message to the terminal to instruct the terminal to directly perform a fallback. In this way, after receiving the RRC connection establishment message, the terminal can quickly execute the RRC connection establishment process, reducing the latency of the terminal waiting for the first network device to obtain context information, avoiding the terminal being in a high-power waiting state for a long time, thereby reducing the terminal's power consumption.

[0319] In some embodiments, if the first network device determines that it does not support the first security algorithm, it may also send a second message to the second network device, the second message being used to instruct the second network device to release the local storage context information of the terminal.

[0320] In some embodiments, when the RRC connection recovery request message includes the eighth information, after determining that the first network device does not support the first security algorithm, the first network device can determine the context information of the second network device stored based on the eighth information, and then send a second message to the second network device to instruct the second network device to release the stored context information of the terminal. This reduces the storage resource consumption of the second network device and improves system resource utilization.

[0321] In step S2204, the terminal sends an RRC connection establishment complete message to the first network device.

[0322] In some embodiments, the terminal sends an RRC connection establishment complete message. In some embodiments, the RRC connection establishment complete message can be sent by the terminal, but is not limited to this; it can also be sent by other entities.

[0323] In some embodiments, the first network device receives an RRC connection establishment complete message. In some embodiments, the RRC connection establishment complete message may be received by the first network device, but is not limited thereto, and may also be received by other entities.

[0324] In one example, the RRC connection setup complete message can be either an RRC Connection Setup Complete message or an RRC Setup Complete message.

[0325] In some embodiments, after completing the RRC connection recovery process, the terminal enters the RRC connection state to prepare for data transmission.

[0326] In some embodiments, after the RRC connection is established, the terminal is in the RRC connected state. At this time, the first network device can update the terminal's configuration information according to the network requirements and changes in the terminal's state.

[0327] In some embodiments, the RRC connection establishment completion message may include fourth information, which instructs the first network device to perform RRC reconfiguration based on the terminal's AS context information.

[0328] In some embodiments, after the terminal sends an RRC connection establishment complete message, the first network device can reconfigure the terminal's context information. If the RRC connection establishment complete message includes fourth information, the first network device can directly use the terminal's AS context information in the RRC inactive state according to the instructions of the fourth information, without needing to reconfigure the AS context information. That is, the first network device does not need to configure all the context information for the terminal, thereby reducing signaling overhead and improving configuration efficiency.

[0329] This completes the process of establishing an RRC connection between the terminal and the first network device.

[0330] In this embodiment, when the terminal sends an RRC connection recovery request message to the first network device, the message carries a first security algorithm used by the terminal before entering the RRC inactive state. If the first network device determines that it does not support the first security algorithm, it will not execute the process of obtaining the terminal's context information and will instead send an RRC connection establishment message to instruct the terminal to directly proceed with the fallback process. In this way, after receiving the RRC connection establishment message, the terminal can quickly execute the RRC connection establishment process, thus reducing the time the terminal spends waiting for the first network device to obtain context information and avoiding the terminal being in a high-power waiting state for an extended period, thereby reducing the terminal's power consumption.

[0331] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0332] Figure 2C is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 2C, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the aforementioned communication method includes steps S2301 to S2306.

[0333] In some embodiments, the communication system 100 described above may include a first network device. In one embodiment, the first network device is an access network device. In one embodiment, a terminal accesses the network through the first network device. In one example, the first network device is a base station.

[0334] In some embodiments, the communication system 100 may further include a second network device. In one embodiment, the second network device is an anchor device of the first network device. The second network device stores the context information of the terminal.

[0335] In some embodiments, the second network device may be deployed in an access network or a core network. In one embodiment, the second network device is deployed in the access network and may be an anchor base station. In another embodiment, the second network device is deployed in the core network and may be used to manage access, such as an AMF (Access Management Function).

[0336] In step S2301, the terminal sends an RRC connection recovery request message to the first network device.

[0337] In some embodiments, the terminal sends an RRC connection restoration request message. In some embodiments, the RRC connection restoration request message may be sent by the terminal, but is not limited to this, and may also be sent by other entities.

[0338] In some embodiments, the first network device receives an RRC connection restoration request message. In some embodiments, the RRC connection restoration request message may be received by the first network device, but is not limited to this; it may also be received by other entities.

[0339] In some embodiments, when a terminal is in an RRC inactive state, it can select a cell to camp on in order to restore the RRC connection on that cell. In one embodiment, when a terminal in an RRC inactive state has uplink data to send, it selects a cell to camp on. In another embodiment, when a terminal in an RRC inactive state receives a paging message from the network side and determines to respond to the paging message, it selects a cell to camp on. In yet another embodiment, when a terminal in an RRC inactive state experiences a tracking area update, it selects a cell to camp on. Of course, the terminal can also select a cell to camp on in other situations, and this disclosure does not specifically limit this.

[0340] In some embodiments, the terminal may select a cell to camp on. In one embodiment, the cell may be a cell that the terminal accessed before entering the RRC inactive state, a new cell that the terminal reselected, or the cell that the terminal is currently in. Of course, the cell may also be other types, and this disclosure does not specifically limit this.

[0341] In some embodiments, the aforementioned cell is provided by a first network device.

[0342] In some embodiments, after the terminal camps on a cell, it can send an RRC connection restoration request message on that cell.

[0343] In some embodiments, the RRC connection recovery request message is the first message. In one example, the RRC connection recovery request message can be an RRC Connection Resume Request message or an RRC Resume Request message.

[0344] In some embodiments, the first message includes eighth information, which is used to indicate the anchor device (such as a second network device) for storing the context information of the terminal.

[0345] In some embodiments, the eighth information may be the device identifier of the storage terminal's context information, such as I-RNTI.

[0346] In step S2302, the first network device sends a context request message to the second network device.

[0347] In some embodiments, the first network device sends a context request message. In some embodiments, the context request message may be sent by the first network device, but is not limited to this, and may also be sent by other entities.

[0348] In some embodiments, the second network device receives a context request message. In some embodiments, the context request message may be received by the second network device, but is not limited thereto, and may also be received by other entities.

[0349] In some embodiments, after receiving an RRC connection recovery request message, the first network device determines the device (e.g., the second network device) that stores the context information of the terminal according to the eighth information, and triggers a context request process to the second network device to obtain the context information of the terminal stored in the second network device.

[0350] In some embodiments, the first network device may send a context request message to the second network device, the context request message being used to request context information of the terminal.

[0351] In some embodiments, the context request message may carry the identifier of the terminal (e.g., a first identifier).

[0352] In step S2303, the second network device sends the terminal's context information to the first network device.

[0353] In some embodiments, the second network device sends the terminal's context information. In some embodiments, the terminal's context information may be sent by the second network device, but is not limited to this; it may also be sent by other entities.

[0354] In some embodiments, the first network device receives context information of the terminal. In some embodiments, the context information of the terminal may be received by the first network device, but is not limited thereto, and may also be received by other entities.

[0355] In some embodiments, after receiving a context request message, the second network device can determine which terminal's context information the first network device is requesting based on the first identifier, and then send the context information of the terminal associated with the first identifier to the first network device in preparation for subsequent recovery of the RRC connection.

[0356] In some embodiments, the context information of the terminal may include security context information, AS context information, partial NAS context information, and other information.

[0357] In one embodiment, the security context information includes information such as the security algorithm, encryption key, integrity protection key, and security configuration parameters. In one example, the security algorithm is the first security algorithm used by the UE before entering the RRC inactive state.

[0358] In one embodiment, the AS context information includes radio bearer configuration, radio resource management information, radio protocol status, cell-related information, etc. In one example, the radio bearer may include DRB and SRB.

[0359] In one embodiment, the NAS context information includes information such as the terminal's identifier and some mobility information.

[0360] In step S2304, the first network device determines that it does not support the first security algorithm.

[0361] In some embodiments, the first network device determines whether the security algorithms it supports include the first security algorithm. If it determines that the security algorithms it supports do not include the first security algorithm, it determines that it does not support the first security algorithm.

[0362] In some embodiments, after obtaining the context information of the terminal, the first network device can determine the first security algorithm used by the terminal based on the security context in the context information. Therefore, the first network device can match the first security algorithm with the security algorithms it supports to determine whether the first network device supports the first security algorithm used by the terminal.

[0363] In some embodiments, when the first network device supports multiple security algorithms, the first network device can match each of the supported security algorithms with the first security algorithm one by one. If the first security algorithm matches one of the multiple security algorithms, that is, the first security algorithm is included among the multiple security algorithms, then the first network device can determine that it supports the first security algorithm. If the first security algorithm does not match any of the multiple security algorithms, that is, the first security algorithm is not included among the multiple security algorithms, then the first network device can determine that it does not support the first security algorithm.

[0364] In some embodiments, if the first network device supports a security algorithm, the first network device may match the supported security algorithm with the first security algorithm. If they match, the first network device may determine that it supports the first security algorithm. If they do not match, the first network device may determine that it supports the first security algorithm.

[0365] In step S2305, the first network device sends an RRC connection recovery message to the terminal.

[0366] In some embodiments, the first network device sends an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be sent by the first network device, but is not limited to this; it may also be sent by other entities.

[0367] In some embodiments, the terminal receives an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be received by the terminal, but is not limited to this; it may also be received by other entities.

[0368] In one example, the RRC connection recovery message can be either an RRC Connection Resume message or an RRC Resume message.

[0369] In some embodiments, the first network device sends an RRC connection restoration message to the terminal to restore the RRC connection and establish radio bearers such as SRB1, SRB2, and DRB. SRB1 and SRB2 are used for signaling transmission, while DRB is used for user data transmission, ensuring that the terminal can communicate efficiently with the network.

[0370] In some embodiments, RRC connection recovery messages may be protected for security and integrity using a third security algorithm.

[0371] In some embodiments, the third security algorithm may be the same as or different from the first security algorithm, and this disclosure does not specifically limit this.

[0372] In some embodiments, the third security algorithm is determined based on predefined information. In one example, the third security information may be determined according to a protocol. Therefore, the third security algorithm can be understood as the default security algorithm.

[0373] In some embodiments, the first network device sends a ninth message to the terminal, which triggers the terminal to use a third security algorithm for security and integrity protection.

[0374] In some embodiments, the ninth message may be sent together with the RRC connection recovery message. In one embodiment, the ninth message may be sent on the same resource as the RRC connection recovery message. In one example, the ninth message may be sent on the same transport block (TB) as the RRC connection recovery message. In one embodiment, the ninth message may be sent on adjacent resources as the RRC connection recovery message. In one example, the ninth message may be sent on the (i-1)th TB, and the RRC connection recovery message may be sent on the i-th TB, where i is a positive integer.

[0375] In some embodiments, the ninth information may be carried in the downlink signaling associated with the TB containing the RRC connection recovery message. In one embodiment, the downlink signaling carrying the ninth information may include DCI, MAC CE, or RRC signaling for scheduling the TB. In one embodiment, the ninth information is included in the scheduling information of the RRC connection recovery message. In one example, the ninth information is carried in a DCI used to schedule the TB containing the RRC connection recovery message. In one embodiment, the ninth information is included in other messages within the TB containing the RRC connection recovery message. In one example, the ninth information is carried in the MAC CE or RRC signaling contained in the TB containing the RRC connection recovery message.

[0376] In some embodiments, the ninth information is carried in the DCI contained in the TB where the RRC connection recovery message is located, and the DCI is used to schedule the TB where the RRC connection recovery message is located.

[0377] In some embodiments, the ninth information is carried in the MAC CE contained in the TB where the RRC connection recovery message is located.

[0378] In some embodiments, the ninth information is carried in the RRC signaling contained in the TB where the RRC connection recovery message is located.

[0379] In some embodiments, the second network device may add a field to the DCI to indicate that the terminal uses a second security algorithm.

[0380] In some embodiments, the second network device may include a MAC CE in the TB where the RRC connection recovery message is located, through which the MAC CE instructs the terminal to use a third security algorithm.

[0381] In some embodiments, when the downlink signaling is MAC CE or RRC signaling, the ninth information is not encrypted. Thus, when the terminal receives the ninth information based on MAC CE or RRC signaling, it can decode the ninth information to determine whether to use the third security algorithm.

[0382] In some embodiments, the RRC connection restoration message sent by the first network device to the terminal may include radio bearer configuration. For example, the radio bearer configuration is used to reactivate or configure SRB1, SRB2, and DRB.

[0383] In some embodiments, after receiving the RRC connection restoration message, the terminal can use a third security algorithm to obtain the RRC connection restoration message according to the instructions of the ninth information, and then obtain the radio bearer configuration. Afterwards, the terminal can activate the radio bearer, restore SRB1, SRB2, and DRB, and complete the RRC restoration process.

[0384] In some embodiments, steps S2302 to S2304 can be omitted. In this case, the first network device and the terminal use the third security algorithm by default. In this case, the step of the first network device sending the ninth information to the terminal can also be omitted.

[0385] In step S2306, the terminal sends an RRC connection restoration complete message to the first network device.

[0386] In some embodiments, the terminal sends an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message can be sent by the terminal, but is not limited to this; it can also be sent by other entities.

[0387] In some embodiments, the first network device receives an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message may be received by the first network device, but is not limited thereto, and may also be received by other entities.

[0388] In some embodiments, after receiving an RRC connection recovery message protected by a third security algorithm, the terminal uses the third security algorithm to decode the message to obtain the RRC connection recovery message.

[0389] In some embodiments, after completing the RRC connection recovery process, the terminal enters the RRC connection state to prepare for data transmission.

[0390] This completes the process of restoring the RRC connection between the terminal and the first network device.

[0391] In this embodiment of the disclosure, the first network device may not perform the operation of determining whether the security algorithm used by the terminal is supported, but directly use the default third security algorithm for integrity protection and security protection. In this way, the latency of RRC connection recovery can be reduced, while the probability of successful RRC connection recovery can be increased, and the robustness of terminal mobility can be improved.

[0392] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0393] Figure 2D is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 2D, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the aforementioned communication method includes steps S2401 to S2406.

[0394] In some embodiments, the communication system 100 described above may include a first network device and a second network device. In one embodiment, the first network device is an access network device. In one embodiment, a terminal accesses the network through the first network device. In one example, the first network device is a base station.

[0395] In one embodiment, the second network device is an anchor device of the first network device. The second network device stores the context information of the terminal.

[0396] In some embodiments, the second network device may be deployed in an access network or a core network. In one embodiment, the second network device is deployed in the access network and may be an anchor base station. In another embodiment, the second network device is deployed in the core network and may be used to manage access, such as an AMF (Access Management Function).

[0397] In step S2401, the terminal sends an RRC connection recovery request message to the first network device.

[0398] The optional implementation of step S2401 can be found in the optional implementation of step S2301 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0399] In step S2402, the first network device sends a context request message to the second network device.

[0400] The optional implementation of step S2402 can be found in the optional implementation of step S2302 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0401] In step S2403, the second network device sends the terminal's context information to the first network device.

[0402] The optional implementation of step S2403 can be found in the optional implementation of step S2303 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0403] In step S2404, the first network device determines that it does not support the first security algorithm.

[0404] The optional implementation of step S2404 can be found in the optional implementation of step S2304 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0405] In step S2405, the first network device sends an RRC connection recovery message to the terminal.

[0406] In some embodiments, the first network device sends an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be sent by the first network device, but is not limited to this; it may also be sent by other entities.

[0407] In some embodiments, the terminal receives an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be received by the terminal, but is not limited to this; it may also be received by other entities.

[0408] In some embodiments, the first network device sends an RRC connection restoration message to the terminal to restore the RRC connection and establish radio bearers such as SRB1, SRB2, and DRB. SRB1 and SRB2 are used for signaling transmission, while DRB is used for user data transmission, ensuring that the terminal can communicate efficiently with the network.

[0409] In one example, the RRC connection recovery message can be either an RRC Connection Resume message or an RRC Resume message.

[0410] In some embodiments, the first network device sends first information to the terminal, the first information instructing the terminal to use a second security algorithm for security and integrity protection, the second security algorithm being different from the first security algorithm. In one embodiment, the second security algorithm is a security algorithm currently being used by the first network device. In another embodiment, the second security algorithm is one of the security algorithms supported by the first network device.

[0411] In some embodiments, the first information may be sent together with the RRC connection recovery message. In one embodiment, the first information may be sent on the same resource as the RRC connection recovery message. In one example, the first information may be sent on the same transport block (TB) as the RRC connection recovery message. In one embodiment, the first information may be sent on adjacent resources as the RRC connection recovery message. In one example, the first information may be sent on the (i-1)th TB, and the RRC connection recovery message may be sent on the i-th TB, where i is a positive integer.

[0412] In some embodiments, the first information may be carried in the downlink signaling associated with the TB containing the RRC connection recovery message. In one embodiment, the downlink signaling carrying the first information may include DCI, MAC CE, or RRC signaling for scheduling the TB. In one embodiment, the first information is included in the scheduling information of the RRC connection recovery message. In one example, the first information is carried in a DCI used to schedule the TB containing the RRC connection recovery message. In one embodiment, the first information is included in other messages within the TB containing the RRC connection recovery message. In one example, the first information is carried in the MAC CE or RRC signaling contained in the TB containing the RRC connection recovery message.

[0413] In some embodiments, the first information is carried in the DCI contained in the TB where the RRC connection recovery message is located, and the DCI is used to schedule the TB where the RRC connection recovery message is located.

[0414] In some embodiments, the first information is carried in the MAC CE contained in the TB where the RRC connection recovery message is located.

[0415] In some embodiments, the first information is carried in the RRC signaling contained in the TB where the RRC connection recovery message is located.

[0416] In some embodiments, the first network device may add a field to the DCI to indicate that the terminal uses a second security algorithm.

[0417] In some embodiments, the first network device may include a MAC CE in the TB where the RRC connection recovery message is located, through which the MAC CE instructs the terminal to use a second security algorithm.

[0418] In some embodiments, when the downlink signaling is MAC CE or RRC signaling, the first information is not encrypted. Thus, when the terminal receives the first information based on MAC CE or RRC signaling, it can decode the first information to determine the second security algorithm indicated by the first network device.

[0419] In some embodiments, the RRC connection restoration message sent by the first network device to the terminal may include a second security algorithm and radio bearer configuration. For example, the radio bearer configuration is used to reactivate or configure SRB1, SRB2, and DRB.

[0420] In some embodiments, after receiving the RRC connection restoration message, the terminal can obtain the RRC connection restoration message according to the second security algorithm indicated by the first information, and then obtain the radio bearer configuration. Afterwards, the terminal can activate the radio bearer, restore the configuration of SRB1, SRB2, and DRB, and complete the RRC restoration process.

[0421] In step S2406, the terminal sends an RRC connection restoration complete message to the first network device.

[0422] In some embodiments, the terminal sends an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message can be sent by the terminal, but is not limited to this; it can also be sent by other entities.

[0423] In some embodiments, the first network device receives an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message may be received by the first network device, but is not limited thereto, and may also be received by other entities.

[0424] In some embodiments, after receiving the RRC connection recovery message protected by the second security algorithm and the first information, the terminal uses the second security algorithm to decode the message according to the instruction of the first information to obtain the RRC connection recovery message.

[0425] In some embodiments, after completing the RRC connection recovery process, the terminal enters the RRC connection state to prepare for data transmission.

[0426] In some embodiments, after step S2403, the first network device may determine that it supports the first security algorithm. In this case, the first network device may use the first security algorithm to protect the RRC connection recovery message before sending the RRC connection recovery message to the terminal. Thus, after receiving the RRC connection recovery message, the terminal can use the first security algorithm to decode the message to obtain the radio bearer configuration, and after completing the RRC connection recovery, send an RRC connection recovery completion message to the first network device.

[0427] This completes the process of restoring the RRC connection between the terminal and the first network device.

[0428] In this embodiment of the disclosure, if the first network device determines that it does not support a first security algorithm used by the terminal, it instructs the terminal to use a specific security algorithm. Thus, after receiving the RRC connection recovery message, the terminal can use the specific security algorithm for security and integrity protection. This reduces the latency of RRC connection recovery, increases the probability of successful RRC connection recovery, and improves the robustness of terminal mobility.

[0429] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0430] Figure 2E is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 2E, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the aforementioned communication method includes steps S2501 to S2505.

[0431] In some embodiments, the communication system 100 described above may include a first network device and a second network device. In one embodiment, the first network device is an access network device. In one embodiment, a terminal accesses the network through the first network device. In one example, the first network device is a base station.

[0432] In one embodiment, the second network device is an anchor device of the first network device. The second network device stores the context information of the terminal.

[0433] In some embodiments, the second network device may be deployed in an access network or a core network. In one embodiment, the second network device is deployed in the access network and may be an anchor base station. In another embodiment, the second network device is deployed in the core network and may be used to manage access, such as an AMF (Access Management Function).

[0434] In step S2501, the terminal sends an RRC connection recovery request message to the first network device.

[0435] The optional implementation of step S2501 can be found in the optional implementation of step S2301 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0436] In step S2502, the first network device sends a context request message to the second network device.

[0437] In some embodiments, the first network device sends a context request message. In some embodiments, the context request message may be sent by the first network device, but is not limited to this, and may also be sent by other entities.

[0438] In some embodiments, the second network device receives a context request message. In some embodiments, the context request message may be received by the second network device, but is not limited thereto, and may also be received by other entities.

[0439] In some embodiments, after receiving an RRC connection recovery request message, the first network device determines the device storing the terminal's context information (e.g., the second network device) based on the eighth information, and initiates a context request process to that device to obtain the terminal's context information.

[0440] In some embodiments, the first network device may send a context request message to the second network device, the context request message being used to request context information of the terminal.

[0441] In some embodiments, the context request message includes fifth information, which indicates the security algorithms supported by the first network device.

[0442] In some embodiments, the first network device may carry a field in the fifth information that can be used to indicate the security algorithms supported by the first network device.

[0443] In some embodiments, the field carried by the fifth information may be an identifier of a security algorithm. In this case, the field may also be a first algorithm identifier. In one embodiment, the first algorithm identifier is used to uniquely identify the security algorithm supported by the first network device. In one embodiment, the security algorithm supported by the first network device may include at least one of an integrity protection algorithm and an encryption algorithm. In this case, the field carried by the second information may include at least one of a first integrity protection algorithm identifier and a first encryption algorithm identifier. The first integrity protection algorithm identifier is used to uniquely identify the integrity protection algorithm supported by the first network device, and the first encryption algorithm identifier is used to uniquely identify the encryption algorithm supported by the first network device.

[0444] In one example, the first integrity protection algorithm identifier can be an algorithm identifier such as 128-NIA1 (Snow 3G-based integrity protection algorithm), 128-NIA2 (AES-based integrity protection algorithm), or 128-NIA3 (ZUC-based integrity protection algorithm).

[0445] In one example, the first encryption algorithm identifier can be an algorithm identifier such as 128-NEA1 (encryption algorithm based on Snow 3G), 128-NEA2 (encryption algorithm based on AES), 128-NEA3 (encryption algorithm based on ZUC), etc.

[0446] In some embodiments, the fields carried by the fifth information may include one or more parameters, which may be parameters associated with a security algorithm to indicate the security algorithm supported by the first network device. In one embodiment, these parameters may include parameters such as algorithm type, key length, and algorithm version.

[0447] In one example, if the parameters carried in the fifth information include: the algorithm type is an encryption algorithm and the key length is 128 bits, it can be determined that the security algorithm supported by the first network device is AES-128.

[0448] In some embodiments, the first network device may support one or more security algorithms. In one example, the fifth piece of information may be a list of security algorithms.

[0449] In some embodiments, the context request message includes fifth information and the identifier of the terminal (e.g., a first identifier).

[0450] In some embodiments, the context request message includes tenth information, which indicates a tunnel endpoint available in the first network device, such as a first tunnel endpoint.

[0451] In some embodiments, the tenth information carries a tunnel endpoint identifier, which is used to identify the GPRS Tunneling Protocol (GTP) and is an identifier for data transmission between the core network (e.g., the second network device) and the base station (e.g., the first network device).

[0452] In some embodiments, the context request message includes fifth information, tenth information, and the identifier of the terminal.

[0453] In some embodiments, after receiving a context request message, the second network device can determine which terminal's context information the first network device is requesting based on the terminal's identifier, thereby obtaining the context information of the terminal associated with the terminal's identifier.

[0454] In some embodiments, the context information of the terminal may include security context information, AS context information, partial NAS context information, and other information.

[0455] In one embodiment, the security context information includes information such as the security algorithm, encryption key, integrity protection key, and security configuration parameters. In one example, the security algorithm is the first security algorithm used by the UE before entering the RRC inactive state.

[0456] In one embodiment, the AS context information includes radio bearer configuration, radio resource management information, radio protocol status, cell-related information, etc. In one example, the radio bearer may include DRB and SRB.

[0457] In one embodiment, the NAS context information includes information such as the terminal's identifier and some mobility information.

[0458] In some embodiments, the second network device, upon obtaining the terminal's context information and the security algorithms supported by the first network device, determines whether the security algorithms supported by the first network device include the first security algorithm used by the terminal before entering the RRC inactive state, and thus determines whether the first network device supports the first security algorithm used by the terminal before entering the RRC inactive state. In some embodiments, the second network device, upon obtaining the terminal's context information and the security algorithms supported by the first network device, determines whether the security algorithms supported by the first network device include the first security algorithm used by the terminal, and thus determines whether the first network device supports the first security algorithm used by the terminal.

[0459] In some embodiments, if the second network device determines that the first network device does not support the first security algorithm used by the terminal before entering the RRC inactive state, when it determines that the security algorithm supported by the first network device does not include the first security algorithm. In one embodiment, if the second network device determines that the first network device does not support the first security algorithm used by the terminal, when it determines that the security algorithm supported by the first network device does not include the first security algorithm.

[0460] In some embodiments, after receiving a context request message, the second network device can obtain the context message of the terminal corresponding to the terminal's identifier based on the terminal's identifier. Then, the second network device can match the security algorithms supported by the first network device with the first security algorithm used by the terminal to determine whether the first network device supports the first security algorithm used by the terminal, and thus determine whether to use context migration to restore the RRC connection.

[0461] In some embodiments, when the first network device supports multiple security algorithms, the second network device can match the multiple security algorithms with the first security algorithm. If the first security algorithm matches one of the multiple security algorithms, i.e., the multiple security algorithms include the first security algorithm, then the first network device supports the first security algorithm used by the terminal. If the first security algorithm does not match any of the multiple security algorithms, i.e., the multiple security algorithms do not include the first security algorithm, then the first network device does not support the first security algorithm used by the terminal.

[0462] In some embodiments, if the first network device supports a security algorithm, the second network device can match the security algorithm with the first security algorithm. If they match, it indicates that the first network device supports the first security algorithm used by the terminal. If they do not match, it indicates that the first network device does not support the first security algorithm used by the terminal.

[0463] In step S2503, the second network device sends a context response message to the first network device.

[0464] In some embodiments, the second network device sends a context response message. In some embodiments, the context response message may be sent by the second network device, but is not limited to this, and may also be sent by other entities.

[0465] In some embodiments, the first network device receives a context response message. In some embodiments, the context response message may be received by the first network device, but is not limited to this, and may also be received by other entities.

[0466] In some embodiments, after receiving a context request message, the second network device sends a context response message to the first network device to trigger the first network device to send an RRC connection recovery message to the terminal.

[0467] In some embodiments, if the second network device determines that the first network device does not support the first security algorithm used by the terminal, the context response message is used to instruct the first network device to resume the RRC connection in a context-free manner.

[0468] In some embodiments, the first network device restores the RRC connection without context migration, without migrating the terminal's context information from the second network device to the first network device.

[0469] In some embodiments, the context response message includes sixth information indicating the tunnel endpoint assigned to the terminal. In one embodiment, when the second network device instructs the first network device to restore the RRC connection using a context-free approach, the tunnel endpoint is associated with a DRB one-to-one.

[0470] In some embodiments, the sixth information may be at least one tunnel endpoint (such as a second tunnel endpoint) among the first tunnel endpoints. When the second network device determines that the first network device is resuming the RRC connection using a context-free approach, it may select at least one tunnel endpoint from the available tunnel endpoints in the first network device, with each tunnel endpoint associated with a DRB. Since the tunnel endpoints are used to identify data transmission between the core network (e.g., the second network device) and the base station (e.g., the first network device), and the DRB is used to identify the data bearer between the terminal and the base station (e.g., the first network device), ensuring that data can be correctly transmitted over the radio interface, a new data transmission path can be established through the association of the tunnel endpoints with the DRB, ensuring continuous data transmission between the first network device and the terminal.

[0471] In some embodiments, the sixth information may also indicate at least one tunnel endpoint on the second network device side, with each tunnel endpoint associated with a DRB. Thus, by associating the tunnel identifier with the DRB, data can be transmitted between the terminal, the second network device, and the first network device.

[0472] In some embodiments, the sixth information may be a tunnel endpoint identifier of at least one tunnel endpoint, with each tunnel endpoint identifier associated with a DRB identifier, which is used to identify a DRB.

[0473] In some embodiments, if the second network device determines that the first network device does not support the first security algorithm used by the terminal, the context response message may further include seventh information, which is used to instruct the first network device not to migrate the terminal's context information.

[0474] In some embodiments, when the second network device determines that the first network device supports the first security algorithm used by the terminal, the context response message is used to instruct the first network device to resume the RRC connection by using context migration.

[0475] In some embodiments, the first network device restores the RRC connection by using context migration, migrating the terminal's context information from the second network device to the first network device.

[0476] In one embodiment, when the second network device instructs the first network device to resume the RRC connection using context migration, the tunnel endpoint is associated with a protocol data unit (PDU) session.

[0477] In some embodiments, the sixth information may be at least one of the first tunnel endpoints. When the second network device determines that the first network device is resuming the RRC connection using context migration, it may select at least one tunnel endpoint available in the first network device, with each tunnel endpoint associated with a PDU session. Since tunnel endpoints are used to identify data transmission between the core network (e.g., the second network device) and the base station (e.g., the first network device), and PDU sessions are used to distinguish different sessions in the core network, associating tunnel endpoints with PDU sessions ensures that the data flow of each PDU session is correctly identified and processed in the core network. This helps to preserve the original session information during context migration and ensures session continuity.

[0478] In some embodiments, the context response message includes eleventh information, which instructs the first network device to release the remaining tunnel endpoints in the first tunnel endpoints, excluding the tunnel endpoint allocated to the terminal. This reduces the storage resource consumption of the second network device and improves its resource utilization.

[0479] In step S2504, the first network device sends an RRC connection recovery message to the terminal.

[0480] In some embodiments, the first network device sends an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be sent by the first network device, but is not limited to this; it may also be sent by other entities.

[0481] In some embodiments, the terminal receives an RRC connection restoration message. In some embodiments, the RRC connection restoration message may be received by the terminal, but is not limited to this; it may also be received by other entities.

[0482] In some embodiments, after receiving the sixth information, the first network device may send an RRC connection recovery message to the terminal based on the sixth information.

[0483] In some embodiments, when the tunnel endpoint indicated by the sixth information is associated with the DRB one-to-one, the first network device determines to restore the RRC connection using a context-free method. In this case, the RRC connection restoration message sent by the first network device to the terminal may include a seventh message. In this way, the terminal can transmit data on a new data transmission path through the association between the tunnel endpoint and the DRB.

[0484] In some embodiments, when the tunnel endpoint indicated by the sixth information is associated with a PDU session, the first network device determines to restore the RRC connection using context migration. In this case, the RRC connection restoration message sent by the first network device to the terminal may include a seventh message. In this way, the terminal can ensure the continuity of the session through the association between the tunnel endpoint and the PDU session.

[0485] In step S2505, the terminal sends an RRC connection restoration complete message to the first network device.

[0486] In some embodiments, the terminal sends an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message can be sent by the terminal, but is not limited to this; it can also be sent by other entities.

[0487] In some embodiments, the first network device receives an RRC connection restoration complete message. In some embodiments, the RRC connection restoration complete message may be received by the first network device, but is not limited thereto, and may also be received by other entities.

[0488] In some embodiments, through step S2504, the terminal sends an RRC connection recovery request message to the first network device to initiate an RRC connection recovery process. The first network device, based on the RRC connection recovery request message, sends an RRC connection recovery message to the terminal. After completing the RRC connection recovery process, the terminal sends an RRC connection recovery completion message to the first network device, causing the first network device to confirm that the RRC connection has been restored.

[0489] In some embodiments, after completing the RRC connection recovery process, the terminal enters the RRC connection state to prepare for data transmission.

[0490] This completes the process of restoring the RRC connection between the terminal and the first network device.

[0491] In this embodiment, the first network device includes a security algorithm supported by the first network device in the context request message sent to the second network device. The second network device then determines whether the first network device supports the security algorithm used by the terminal. If it is determined that the first network device does not support the security algorithm used by the terminal, the RRC connection can be restored using a non-contextual migration method. This reduces signaling interaction between the first and second network devices, speeds up the RRC connection restoration process, and reduces the signaling load on the network.

[0492] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0493] In some embodiments, the terms "uplink", "uplink", and "physical uplink" can be used interchangeably, as can the terms "downlink", "downlink", and "physical downlink".

[0494] In some embodiments, "acquire," "get," "obtain," "receive," "transmit," "bidirectional transmission," and "send and / or receive" can be used interchangeably and can be interpreted as receiving from other entities, acquiring from protocols, acquiring from higher layers, obtaining through self-processing, or autonomous implementation. Protocols include, for example, at least one of the 3GPP protocol, Wi-Fi protocol, and audio and / or video protocols.

[0495] In some embodiments, terms such as “send,” “transmit,” “report,” “distribute,” “transmit,” “bidirectional transmission,” “send and / or receive” can be used interchangeably.

[0496] Figure 3A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 3A, the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the communication method includes steps S3101 and S3102.

[0497] In step S3101, the first network device broadcasts the second information.

[0498] The optional implementation of step S3101 can be found in the optional implementation of step S2101 in Figure 2A, as well as other related parts in the embodiments involved in Figure 2A, which will not be repeated here.

[0499] In some embodiments, if the security algorithm supported by the first network device does not include the first security algorithm, step S3102 is performed.

[0500] In step S3102, the terminal and the first network device perform the RRC connection establishment process.

[0501] The optional implementation of step S3102 can be found in the optional implementations of steps S2102 and S2103 in Figure 2A, as well as other related parts in the embodiments involved in Figure 2A, which will not be repeated here.

[0502] In this embodiment of the disclosure, the first network device directly broadcasts the security algorithms it supports. In this way, the terminal residing on the first network device can determine whether the first network device supports the security algorithm used by the terminal based on the security algorithms supported by the first network. If it is determined that the first network device does not support the security algorithm used by the terminal, the terminal can quickly fall back and initiate the RRC connection establishment process, thereby reducing latency and quickly establishing a secure connection with the network.

[0503] Figure 3B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 3B, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the aforementioned communication method includes steps S3201 and S3202.

[0504] In step S3201, the first network device broadcasts the second information.

[0505] The optional implementation of step S3201 can be found in the optional implementation of step S2101 in Figure 2A, as well as other related parts in the embodiments involved in Figure 2A, which will not be repeated here.

[0506] In some embodiments, if the security algorithm supported by the first network device includes a first security algorithm, step S3202 is executed.

[0507] In step S3202, the terminal and the first network device perform an RRC connection restoration process.

[0508] The optional implementation of step S3202 can be found in the optional implementations of steps S2102 and S2104 in Figure 2A, as well as other related parts in the embodiments involved in Figure 2A, which will not be repeated here.

[0509] In this embodiment of the disclosure, the first network device broadcasts the security algorithms it supports. In this way, the terminal residing on the first network device can determine whether the first network device supports the security algorithm used by the terminal based on the security algorithms supported by the first network. If it is determined that the first network device does not support the security algorithm used by the terminal, the terminal can send an RRC connection recovery request message to the first network device to quickly establish an RRC connection. This can reduce latency and quickly establish a secure connection with the network.

[0510] Figure 3C is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 3C, the embodiment of the present disclosure relates to a communication method executed by the aforementioned communication system. In one example, the communication method includes steps S3301 to S3306.

[0511] In step S3301, the first network device broadcasts the second information.

[0512] The optional implementation of step S3301 can be found in the optional implementations of steps S2101 and S2102 in Figure 2A, as well as other related parts in the embodiments involved in Figure 2A, which will not be repeated here.

[0513] In some embodiments, if the security algorithm supported by the first network device does not include the first security algorithm, step S3302 or step S3303 is executed.

[0514] In step S3302, the terminal sends an RRC connection recovery request message to the first network device.

[0515] In some embodiments, the RRC connection restoration request message carries third information. In this case, the optional implementation of step S3302 can be found in the optional implementation of step S2201 in FIG2B, as well as other related parts in the embodiments involved in FIG2B, which will not be repeated here.

[0516] In some embodiments, when the RRC connection recovery request message does not carry third information, the optional implementation of step S3302 can be found in the optional implementation of step S2301 in FIG2C, as well as other related parts in the embodiments involved in FIG2C, which will not be repeated here.

[0517] In some embodiments, when the RRC connection recovery request message does not carry third information, the optional implementation of step S3302 can be found in the optional implementation of step S2401 in FIG2D, as well as other related parts in the embodiments involved in FIG2D, which will not be repeated here.

[0518] In some embodiments, when the RRC connection recovery request message does not carry third information, the optional implementation of step S3302 can be found in the optional implementation of step S2501 in FIG2E, as well as other related parts in the embodiments involved in FIG2E, which will not be repeated here.

[0519] In some embodiments, if the RRC connection recovery request message carries third information, steps S3303 to S3304 (corresponding to a in FIG3C) are executed after step S3302.

[0520] In some embodiments, if the RRC connection recovery request message does not carry third information, steps S3305 to S3306 (corresponding to b in FIG3C) are executed after step S3302.

[0521] In step S3303, the first network device sends an RRC connection establishment message to the terminal.

[0522] The optional implementation of step S3303 can be found in the optional implementation of steps S2202 to S2203 in Figure 2B, as well as other related parts in the embodiments involved in Figure 2B, which will not be repeated here.

[0523] In step S3304, the terminal sends an RRC connection establishment complete message to the first network device.

[0524] The optional implementation of step S3304 can be found in the optional implementation of step S2204 in Figure 2B, as well as other related parts in the embodiments involved in Figure 2B, which will not be repeated here.

[0525] In step S3305, the first network device sends an RRC connection recovery message to the terminal.

[0526] In some embodiments, after step S3302, the first network device sends a context request message to the second network device, the second network device sends the terminal's context information to the first network device, and the first network device determines that it does not support the first security algorithm. Then, step S3305 is executed. In this case, optional implementations of the above steps can be found in the optional implementations of steps S2302 to S2305 in FIG2C, and other related parts in the embodiments involved in FIG2C, which will not be repeated here.

[0527] In some embodiments, after step S3302, the first network device sends a context request message to the second network device, the second network device sends the terminal's context information to the first network device, and the first network device determines that it does not support the first security algorithm. Then, step S3305 is executed. In this case, optional implementations of the above steps can be found in the optional implementations of steps S2402 to S2405 in FIG. 2D, and other related parts in the embodiments involved in FIG. 2D, which will not be repeated here.

[0528] In some embodiments, after step S3302, the first network device sends a context request message to the second network device, the second network device sends a context response message to the first network device, and then step S3305 is executed. In this case, the optional implementations of the above steps can be found in the optional implementations of steps S2502 to S2504 of FIG. 2E, as well as other related parts in the embodiments involved in FIG. 2E, which will not be repeated here.

[0529] In step S3306, the terminal sends an RRC connection restoration complete message to the first network device.

[0530] The optional implementation of step S3306 can be found in the optional implementation of step S2306 in Figure 2C, as well as other related parts in the embodiments involved in Figure 2C, which will not be repeated here.

[0531] Figure 4A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 4A, the communication method includes steps S4101 to S4102.

[0532] In step S4101, the terminal sends a first message to the first network device.

[0533] In some embodiments, the first message is used for the terminal to request the establishment of an RRC connection with the first network device.

[0534] In some embodiments, the first message is an RRC connection establishment request message.

[0535] In some embodiments, the first network device does not support the first security algorithm used by the terminal before entering the inactive state, the first security algorithm being used for security protection and integrity protection.

[0536] In some embodiments, the first network device broadcasts second information, which includes a security algorithm supported by the first network device, and the second information is used to trigger the terminal to send a first message.

[0537] When the first message is an RRC connection establishment request message, the optional implementation of step S4101 can be found in the optional implementation of steps S2101 to S2103 in Figure 2A, as well as other related parts in the embodiment involved in Figure 2A, which will not be repeated here.

[0538] In some embodiments, the first message is an RRC connection recovery request message.

[0539] In some embodiments, the first message includes third information, which is used to indicate the first security algorithm.

[0540] In some embodiments, when the first message is an RRC connection recovery request message, the optional implementation of step S4101 can be found in the optional implementation of steps S2101 to S2102 and step S2104 in FIG2A, as well as other related parts in the embodiments involved in FIG2A, which will not be repeated here.

[0541] In some embodiments, when the first message is an RRC connection recovery request message and the first message includes third information, the optional implementation of step S4101 can be found in the optional implementation of step S2201 in FIG2B, as well as other related parts in the embodiments involved in FIG2B, which will not be repeated here.

[0542] In some embodiments, when the first message is an RRC connection recovery request message, the optional implementation of step S4101 can be found in the optional implementation of step S2301 in FIG2C, as well as other related parts in the embodiments involved in FIG2C, which will not be repeated here.

[0543] In some embodiments, when the first message is an RRC connection recovery request message, the optional implementation of step S4101 can be found in the optional implementation of step S2401 in FIG2D, as well as other related parts in the embodiments involved in FIG2D, which will not be repeated here.

[0544] In some embodiments, when the first message is an RRC connection recovery request message, the optional implementation of step S4101 can be found in the optional implementation of step S2501 in FIG2E, as well as other related parts in the embodiments involved in FIG2E, which will not be repeated here.

[0545] In step S4102, the first network device sends an RRC connection establishment message or an RRC connection recovery message to the terminal.

[0546] In some embodiments, when the first network device sends an RRC connection establishment message to the terminal, after step S4101, the first network device determines that it does not support the first security algorithm, and then executes step S4102. In this case, the optional implementations of the above steps can be found in the optional implementations of steps S2202 to S2203 in FIG2B, as well as other related parts in the embodiments involved in FIG2B, which will not be repeated here.

[0547] In some embodiments, when the first network device sends an RRC connection recovery message to the terminal, after step S4101, the first network device sends a context request message to the second network device, the second network device sends the terminal's context information to the first network device, and the first network device determines that it does not support the first security algorithm. Then, step S4102 is executed. In this case, optional implementations of the above steps can be found in the optional implementations of steps S2302 to S2305 in FIG2C, and other related parts in the embodiments involved in FIG2C, which will not be repeated here.

[0548] In some embodiments, when the first network device sends an RRC connection recovery message to the terminal, after step S4101, the first network device sends a context request message to the second network device, the second network device sends the terminal's context information to the first network device, and the first network device determines that it does not support the first security algorithm. Then, step S4102 is executed. In this case, optional implementations of the above steps can be found in the optional implementations of steps S2402 to S2405 in FIG. 2D, and other related parts in the embodiments involved in FIG. 2D, which will not be repeated here.

[0549] In some embodiments, when the first network device sends an RRC connection recovery message to the terminal, after step S4101, the first network device sends a context request message to the second network device, the second network device sends a context response message to the first network device, and then step S4102 is executed. In this case, optional implementations of the above steps can be found in the optional implementations of steps S2502 to S2504 in FIG2E, as well as other related parts in the embodiments involved in FIG2E, which will not be repeated here.

[0550] Figure 4B is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in Figure 4, the communication method includes steps S4201 to S4202.

[0551] In step S4201, the first network device sends a context request message to the second network device.

[0552] In some embodiments, the context request message includes fifth information, which indicates the security algorithms supported by the first network device.

[0553] The optional implementation of step S4201 can be found in the optional implementation of step S2502 in Figure 2E, as well as other related parts in the embodiments involved in Figure 2E, which will not be repeated here.

[0554] In step S4202, the second network device sends a context response message to the first network device.

[0555] In some embodiments, the context response message is used by the first network device to restore the RRC connection using a non-contextual migration approach, and the context response message is used to trigger the first network device to send an RRC connection restoration message to the terminal.

[0556] The optional implementation of step S4202 can be found in the optional implementation of step S2503 in Figure 2E, as well as other related parts in the embodiments involved in Figure 2E, which will not be repeated here.

[0557] In the following, specific embodiments of the present disclosure will be described by way of example.

[0558] In some embodiments, Scheme 1 is provided: the base station broadcasts its own list of supported security algorithms, and the UE preferentially camps on the security algorithms that it supports before entering RRC_INACTIVE. If the camped cell does not support the security algorithms to be used, the UE triggers the RRC connection establishment process, but before initiating the RRCSetupRequest, it first returns to the idle state and then initiates the RRC connection establishment process.

[0559] In some embodiments, Scheme 2 is provided: When the UE initiates an RRCResumeRequst message, the message carries the security algorithm ID used last time. If the current serving base station finds that it does not support the algorithm ID, it does not perform the process of requesting the security context from the anchor base station, but directly performs the fallback process, that is, sends an RRCsetup message to the UE. Optionally, the anchor base station is instructed to release the UE's context.

[0560] In some embodiments, for scheme 1 / 2, the UE carries indication information in the RRCSetupComplete message (MSG5), which indicates that the delta configuration can be performed based on the previous UE AS context in the first subsequent RRCReconfiguration message.

[0561] In some embodiments, Scheme 3 is provided: the system specifies a default security algorithm or a designated security algorithm broadcast by the system. During the RRC connection recovery process, MSG4 uses the key generated by the default security algorithm for encryption and integrity protection.

[0562] In some embodiments, Scheme 4 is provided: During the RRC connection recovery process, the current serving base station is allowed to change its security algorithm. A key is generated based on the security algorithm selected by the current serving base station for encryption and integrity protection of MSG4. Simultaneously, the security algorithm used by the current serving base station is indicated in the TB containing the RRCResume message, for example, through scheduling information in the TB containing the RRCResume message, in the DCI, or by including a MAC CE or RRC signaling in the TB containing the RRCResume message to indicate the security algorithm used by MSG4. The MAC CE or RRC signaling can use the new key to perform integrity protection, but without encryption.

[0563] In some embodiments, FIG5A is an exemplary interactive schematic diagram of a communication method according to an embodiment of the present disclosure. As shown in FIG5A, the following embodiment process is given based on scheme 3 / 4:

[0564] 1. UE 501 initiates an RRCResumeRequest message to the current serving base station, triggering the RRC connection recovery process.

[0565] 2. The current serving base station 502 determines the gNB ID (identifier of the anchor gNB) of the base station storing the UE context based on the I-RNTI carried in the RRCResumeRequest message, and initiates the context request process by sending a context request message to the anchor base station 503. The anchor base station 503 then sends the UE's context information to the current serving base station 502 based on the context request message.

[0566] 3. After obtaining the UE's context information (e.g., the UE's security context), the current serving base station 502 determines whether it supports the currently used security algorithm. The current serving base station 502 can:

[0567] Option 1: Use the system's default security algorithm for MSG4 security protection;

[0568] Option 2: Use the currently used security algorithm for the security protection of MSG4;

[0569] Option 3: Use a security algorithm supported by the current base station 502, which is different from the security algorithm used by the previous UE 501 for the security protection of MSG4.

[0570] 4. The current serving base station 502 sends an RRCResume message to the UE 501. The RRCResume message corresponds to the DCI of the TB, or the MAC CE within the TB, or the RRC signaling, indicating the security algorithm used by MSG4.

[0571] In one embodiment, the downlink signaling in the TB corresponding to the RRC Resume message includes one of the following: DCI; MAC CE; RRC signaling.

[0572] 5. UE 501 sends an RRCResumeComplete message to the current serving base station 502, at which point RRC recovery is successful.

[0573] In some embodiments, scheme 5 is provided: When the UE initiates an RRCResumeRequest message to the current serving base station, the current serving base station requests an AS Context Request message from the anchor base station, the message containing the security algorithms supported by the current serving base station. If the anchor base station finds that the current serving base station does not support the security algorithm being used, the anchor base station decides to use RRC connection recovery without context migration.

[0574] In some embodiments, FIG5B is an exemplary interaction diagram of a communication method according to an embodiment of the present disclosure. As shown in FIG5B, the following embodiment process is given based on scheme 5:

[0575] 1. UE 511 sends an RRCResumeRequest message to the current serving base station 512, triggering the RRC connection recovery process.

[0576] 2. The current serving base station 512 determines the gNB ID (identifier of the anchor gNB) of the base station storing the UE context based on the I-RNTI carried in the RRCResumeRequest message, and initiates the context request process by sending a context request message to the anchor base station 513. After obtaining the security context, the current serving base station carries a list of security algorithm IDs it supports and / or a list of available GTP TEI IDs allocated by the current serving base station in the context request message.

[0577] 3. After receiving the context request message, anchor base station 513 determines whether the security algorithm previously used by UE 511 is supported by the current serving base station. If not, the anchor base station decides to restore the RRC connection using a non-context migration approach. In the context response message, it indicates at least one GTP TEI ID used, with each GTP TEI ID associated with a DRB ID. Simultaneously, anchor base station 513 allocates at least one GTP TEI ID on its own side, which is also associated with a DRB ID. Optionally, it may carry an indication indicating a non-context migration. If context migration is required, anchor base station 513 indicates the used GTP TEI ID, which is associated with a PDU session ID. If no GTP TEI ID is used, the current serving base station 512 releases it.

[0578] 4. The current serving base station 512 sends an RRRCResume message to UE 511.

[0579] 5. UE 511 sends an RRCResumeComplete message to the current serving base station 512, at which point RRC recovery is successful.

[0580] In this embodiment of the disclosure, when the current serving base station does not support the security algorithm previously used by the UE, a fallback process or key update can be quickly implemented, thereby reducing the RRC connection recovery latency, quickly realizing subsequent data transmission and reception, and improving the probability of successful RRC connection recovery, thus enhancing the robustness of terminal mobility.

[0581] In the embodiments disclosed herein, some or all of the steps and their optional implementations may be arbitrarily combined with some or all of the steps in other embodiments, or may be arbitrarily combined with the optional implementations in other embodiments.

[0582] This disclosure also proposes an apparatus (also referred to as a communication device, etc.) for implementing any of the above methods. For example, an apparatus is proposed that includes units or modules for implementing the steps performed by the terminal in any of the above methods. Furthermore, another apparatus is also proposed...

[0583] The device includes units or modules for implementing the steps performed by the network device (e.g., the first network device, the second network device, etc.) in any of the above methods.

[0584] It should be understood that the division of units or modules in the above device is only a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, the units or modules in the device can be implemented by a processor calling software: for example, the device includes a processor connected to a memory containing instructions. The processor calls the instructions stored in the memory to implement any of the above methods or to implement the functions of the units or modules in the above device. The processor can be, for example, a general-purpose processor, such as a central processing unit (CPU) or a microprocessor, and the memory can be internal or external to the device. Alternatively, the units or modules in the device can be implemented in the form of hardware circuits. The functionality of some or all of the units or modules can be achieved through the design of these hardware circuits, which can be understood as one or more processors. For example, in one implementation, the hardware circuit is an application-specific integrated circuit (ASIC). The functionality of some or all of the units or modules is achieved through the design of the logical relationships between the components within the circuit. In another implementation, the hardware circuit can be implemented using a programmable logic device (PLD). Taking a field-programmable gate array (FPGA) as an example, it can include a large number of logic gates. The connection relationships between the logic gates are configured through a configuration file, thereby achieving the functionality of some or all of the units or modules. All units or modules of the above device can be implemented entirely through processor-called software, entirely through hardware circuits, or partially through processor-called software with the remaining parts implemented through hardware circuits.

[0585] In this embodiment, the processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction read and execute capabilities, such as a CPU, microprocessor, graphics processing unit (GPU) (which can be understood as a microprocessor), or digital signal processor (DSP). In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. The logical relationships of the aforementioned hardware circuits are fixed or reconfigurable. For example, the processor is a hardware circuit implemented by an ASIC or PLD, such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the process of the processor loading instructions to implement the functions of some or all of the above units or modules. Furthermore, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as a neural network processing unit (NPU), tensor processing unit (TPU), deep learning processing unit (DPU), etc.

[0586] Figure 6 is a schematic diagram of a communication device according to an embodiment of the present disclosure. As shown in Figure 6, the communication device 600 may include a transceiver module 601.

[0587] In some embodiments, the communication device 600 may be a first network device. In some embodiments, the transceiver module 601 is configured to receive a first message sent by a terminal, the first message being a request from the terminal to establish a Radio Resource Control (RRC) connection with the first network device; and to send to the terminal one of the following: an RRC connection restoration message; or an RRC connection establishment message; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security and integrity protection. Optionally, the transceiver module 601 is used to perform at least one of the communication steps (e.g., steps S2101, S2103 to S2104, S2201, S2203 to S2204, S2301 to S2303, S2305 to S2306, S2401 to S2404, S2405 to S2406, S2501 to S2505, but not limited thereto) performed by the first network device in any of the above methods, which will not be elaborated here. In some embodiments, the communication device 600 may further include a processing module, which is used to perform at least one of the other steps (e.g., steps S2202, S2304, S2404, but not limited thereto) performed by the first device in any of the above methods, which will not be elaborated here.

[0588] In some embodiments, the communication device 600 may be a second network device. In some embodiments, the transceiver module 601 is configured to receive a context request message sent by the first network device, the context request message including sixth information, the sixth information being used to indicate the security algorithm supported by the first network device; according to the context request message, to send a context response message to the first network device, the context response message being used to instruct the first network device to restore the RRC connection using a context-free approach, the context response message being used to trigger the first network device to send an RRC connection restoration message to the terminal. Optionally, the transceiver module 601 is configured to perform at least one of the communication steps such as sending and / or receiving performed by the second device in any of the above methods (e.g., steps S2302 to S2303, steps S2402 to S2403, steps S2502 to S2503, but not limited thereto), which will not be elaborated here.

[0589] In some embodiments, the communication device 600 may be a terminal. In some embodiments, the transceiver module 601 is configured to send a first message to a first network device, the first message being used to request the establishment of an RRC connection with the first network device; and to receive an RRC connection recovery message or an RRC connection establishment message sent by the first network device; wherein the first network device does not support a first security algorithm used by the terminal before entering an inactive state, the first security algorithm being used for security protection and integrity protection. Optionally, the transceiver module 601 is configured to perform at least one of the communication steps (e.g., steps S2101, S2103 to S2104, S2201, S2203 to S2204, S2301, S2305 to S2306, S2401, S2405 to S2406, S2501, S2504 to S2505, but not limited thereto) performed by the first device in any of the above methods, which will not be elaborated here. In some embodiments, the communication device 600 may further include a processing module for performing at least one of the other steps (e.g., step S2102, but not limited thereto) performed by the first device in any of the above methods, which will not be described in detail here.

[0590] In some embodiments, the transceiver module may include a transmitting module and / or a receiving module, which may be separate or integrated. Optionally, the transceiver module may be interchangeable with a transceiver.

[0591] In some embodiments, the processing module may be a single module or may include multiple sub-modules. Optionally, the multiple sub-modules may each perform all or part of the steps required by the processing module.

[0592] In some embodiments, the processing module can be replaced by the processor, and the transceiver module can be replaced by the transceiver.

[0593] Figure 7A is a schematic diagram of the structure of a communication device according to an embodiment of the present disclosure. The communication device 7100 can be a network device (e.g., a first network device, a second network device, etc.), a terminal (e.g., a user equipment, etc.), a chip, chip system, or processor that supports the network device in implementing any of the above methods, or a chip, chip system, or processor that supports the terminal in implementing any of the above methods. The communication device 7100 can be used to implement the methods described in the above method embodiments; for details, please refer to the descriptions in the above method embodiments.

[0594] As shown in Figure 7A, the communication device 7100 is used to execute any of the above methods. In some embodiments, the communication device 7100 includes one or more processors 7101. The processor 7101 may be a general-purpose processor or a special-purpose processor, such as a baseband processor or a central processing unit. The baseband processor may be used to process communication protocols and communication data, and the central processing unit may be used to control communication devices (e.g., base stations, baseband chips, terminal devices, terminal device chips, DUs or CUs, etc.), execute programs, and process program data. Optionally, the communication device 7100 is used to execute any of the above methods. Optionally, one or more processors 7101 are used to invoke instructions to cause the communication device 7100 to execute any of the above methods.

[0595] In some embodiments, the communication device 7100 further includes one or more transceivers 7102. When the communication device 7100 includes one or more transceivers 7102, the transceivers 7102 perform at least one of the communication steps such as sending and / or receiving in the above method (e.g., steps S2101, S2103 to S2104, S2201, S2203 to S2204, S2301 to S2303, S2305 to S2306, S2401 to S2403, S2405 to S2406, S2501 to S2505, but not limited thereto), and the processor 7101 performs at least one of other steps (e.g., steps S2102, S2202, S2304, S2404, but not limited thereto). In optional embodiments, the transceiver may include a receiver and / or a transmitter, which may be separate or integrated. Optionally, the terms transceiver, transceiver unit, transceiver, transceiver circuit, interface circuit, interface, etc., can be used interchangeably; the terms transmitter, transmitting unit, transmitter, transmitting circuit, etc., can be used interchangeably; the terms receiver, receiving unit, receiver, receiving circuit, etc., can be used interchangeably.

[0596] In some embodiments, the communication device 7100 further includes one or more memories 7103 for storing data and / or instructions. Optionally, one or more processors 7101 are used to invoke instructions stored in the memory 7103 to cause the communication device 7100 to perform any of the above methods. Optionally, all or part of the memory 7103 may also be located outside the communication device 7100. In an optional embodiment, the communication device 7100 may include one or more interface circuits 7104. Optionally, the interface circuit 7104 is connected to the memory 7102 and can be used to receive data and / or instructions from the memory 7102 or other devices, and can be used to send data and / or instructions to the memory 7102 or other devices. For example, the interface circuit 7104 can read data and / or instructions stored in the memory 7102 and send the data and / or instructions to the processor 7101.

[0597] The communication device 7100 described in the above embodiments may be a network device or a terminal, but the scope of the communication device 7100 described in this disclosure is not limited thereto, and the structure of the communication device 7100 may not be limited by FIG. 7A. The communication device may be a standalone device or may be part of a larger device. For example, the communication device may be: (1) a standalone integrated circuit IC, or chip, or chip system or subsystem; (2) a collection of one or more ICs, optionally, the IC collection may also include storage components for storing data, programs and / or instructions; (3) an ASIC, such as a modem; (4) a module that can be embedded in other devices; (5) a receiver, terminal device, smart terminal device, cellular phone, wireless device, handheld device, mobile unit, vehicle device, network device, cloud device, artificial intelligence device, etc.; (7) others, etc.

[0598] Figure 7B is a schematic diagram of the structure of a chip according to an embodiment of the present disclosure. For cases where the communication device 7100 can be a chip or a chip system, please refer to the schematic diagram of the chip 7200 shown in Figure 7B, but it is not limited thereto.

[0599] Chip 7200 includes one or more processors 7201. Chip 7200 is used to perform any of the above methods.

[0600] In some embodiments, chip 7200 further includes one or more interface circuits 7202. Optionally, terms such as interface circuit, interface, and transceiver pin can be used interchangeably. In some embodiments, chip 7200 further includes one or more memories 7203 for storing data and / or instructions. Optionally, all or part of the memories 7203 may be located outside of chip 7200. Optionally, the interface circuit 7202 is connected to the memories 7203, and the interface circuit 7202 can be used to receive data and / or instructions from the memories 7203 or other devices, and the interface circuit 7202 can be used to send data and / or instructions to the memories 7203 or other devices. For example, the interface circuit 7202 can read data and / or instructions stored in the memories 7203 and send the data and / or instructions to the processor 7201.

[0601] In some embodiments, the interface circuit 7202 performs at least one of the communication steps such as sending and / or receiving in the above-described method (e.g., steps S2101, S2103 to S2104, S2201, S2203 to S2204, S2301 to S2303, S2305 to S2306, S2401 to S2403, S2405 to S2406, S2501 to S2505, but not limited thereto). The interface circuit 7202 performing the communication steps such as sending and / or receiving in the above-described method refers, for example, to the interface circuit 7202 performing data and / or instruction interaction between the processor 7201, the chip 7200, the memory 7203, or the transceiver device. In some embodiments, the processor 7201 performs at least one of other steps (e.g., steps S2102, S2202, S2304, S2404, but not limited thereto).

[0602] The modules and / or devices described in the various embodiments, such as virtual devices, physical devices, and chips, can be combined or separated arbitrarily as needed. Optionally, some or all steps can also be performed collaboratively by multiple modules and / or devices, which is not limited here.

[0603] This disclosure also proposes a storage medium storing instructions that, when executed on a communication device, cause the communication device to perform any of the methods described above. Optionally, the storage medium is an electronic storage medium. Optionally, the storage medium is a computer-readable storage medium, but not limited thereto; it may also be a storage medium readable by other devices. Optionally, the storage medium may be a non-transitory storage medium, but not limited thereto; it may also be a temporary storage medium.

[0604] This disclosure also provides a program product, including a program and / or instructions, which, when executed by a communication device, cause the communication device to perform any of the above methods. Optionally, the program product is a computer program product. Optionally, the program product is stored on the storage medium.

[0605] This disclosure also proposes a computer program that, when run on a computer, causes the computer to perform any of the above methods.

[0606] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0607] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A communication method, performed by a first network device, the method comprising: The receiving terminal sends a first message, which is used by the terminal to request the establishment of a Radio Resource Control (RRC) connection with the first network device. Send one of the following to the terminal: RRC connection restoration message; RRC connection establishment message; The first network device does not support the first security algorithm used by the terminal before entering the inactive state. The first security algorithm is used for security protection and integrity protection.

2. The method according to claim 1, wherein, The method further includes: Send a first message to the terminal, the first message being used to instruct the terminal to use a second security algorithm for security and integrity protection, the second security algorithm being different from the first security algorithm.

3. The method according to claim 2, wherein, The first information is carried in the downlink signaling associated with the transport block TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: Downlink control information (DCI) is used to schedule the TB. Media access control MAC control unit CE; RRC signaling.

4. The method according to claim 3, wherein, The downlink signaling is either the MAC CE or the RRC signaling, and the first information is not encrypted.

5. The method according to any one of claims 2 to 4, wherein, The method further includes: According to the first message, a context request message is sent to the second network device. The context request message is used to request the context information of the terminal. The first message is an RRC connection recovery request message. The terminal receives context information sent by the second network device according to the context request message, wherein the context information includes the first security algorithm; Based on the context information of the terminal, it is determined that the first network device does not support the first security algorithm.

6. The method according to claim 1, wherein, The method further includes: The RRC connection recovery message is protected for security and integrity using a third security algorithm, which is determined based on predefined information.

7. The method according to claim 1, wherein, The method further includes: Broadcast a second message, which indicates the security algorithm supported by the first network device and triggers the terminal to send the first message.

8. The method according to claim 7, wherein, The security algorithm supported by the first network device does not include the first security algorithm, and the first message is an RRC connection establishment request message.

9. The method according to claim 1, wherein, The first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that it does not support the first security algorithm.

10. The method according to claim 9, wherein, The method further includes: A second message is sent to a second network device, the second message being used to instruct the second network device to release the context information of the terminal.

11. The method according to any one of claims 7 to 10, wherein, The method further includes: The first network device receives an RRC connection establishment complete message sent by the terminal based on the RRC connection establishment message. The RRC connection establishment complete message includes fourth information, which is used to instruct the first network device to perform RRC reconfiguration based on the access layer context information of the terminal.

12. The method according to claim 1, wherein, The method further includes: Send a context request message to the second network device, the context request message including fifth information, the fifth information being used to indicate the security algorithms supported by the first network device; The first network device receives a context response message sent by the second network device based on the context request message. The context response message is used to instruct the first network device to restore the RRC connection using a context-free approach. The context response message is also used to trigger the first network device to send the RRC connection restoration message to the terminal.

13. The method according to claim 11, wherein, The context response message includes a sixth piece of information, which indicates the tunnel endpoint assigned to the terminal. The tunnel endpoint is associated with a Data Radio Bearer (DRB) and the RRC connection recovery message includes the sixth piece of information.

14. The method according to claim 12 or 13, wherein, The context response message also includes a seventh message, which indicates that the context information of the terminal should not be migrated.

15. The method according to any one of claims 5 to 14, wherein, The second network device is the anchor device of the first network device, and the second network device stores the context information of the terminal.

16. A communication method, executed by a terminal, the method comprising: Send a first message to the first network device, the first message being used to request the establishment of a Radio Resource Control (RRC) connection with the first network device; Receive an RRC connection recovery message or an RRC connection establishment message sent by the first network device; The first network device does not support the first security algorithm used by the terminal before entering the inactive state. The first security algorithm is used for security protection and integrity protection.

17. The method according to claim 16, wherein, The method further includes: The terminal receives first information sent by the first network device, the first information being used to instruct the terminal to use a second security algorithm for security and integrity protection, the second security algorithm being different from the first security algorithm.

18. The method according to claim 17, wherein, The first information is carried in the downlink signaling associated with the transport block TB where the RRC connection recovery message is located, and the downlink signaling includes one of the following: Downlink control information (DCI) is used to schedule the TB. Media access control MAC control unit CE; RRC signaling.

19. The method according to claim 18, wherein, The downlink signaling is either the MAC CE or the RRC signaling, and the first information is not encrypted.

20. The method of claim 16, wherein, The RRC connection recovery message is protected for security and integrity by a third security algorithm, which is determined based on predefined information.

21. The method according to claim 16, wherein, The method further includes: The terminal receives second information broadcast by the first network device, the second information being used to indicate the security algorithms supported by the first network device, and the second information being used to trigger the terminal to send the first message.

22. The method according to claim 21, wherein, The security algorithm supported by the first network device does not include the first security algorithm, and the first message is an RRC connection establishment request message.

23. The method according to claim 16, wherein, The first message includes third information, which is used to indicate the first security algorithm; the RRC connection establishment message is sent by the first network device when it determines, based on the third information, that it does not support the first security algorithm.

24. The method according to any one of claims 16 to 23, wherein, The method further includes: Based on the RRC connection establishment message, an RRC connection establishment complete message is sent to the first network device. The RRC connection establishment complete message includes fourth information, which is used to instruct the first network device to perform RRC reconfiguration based on the access layer context information of the terminal.

25. A communication method performed by a second network device, the method comprising: Receive a context request message sent by a first network device, the context request message including fifth information, the fifth information being used to indicate the security algorithms supported by the first network device; Based on the context request message, a context response message is sent to the first network device. The context response message is used to instruct the first network device to restore the Radio Resource Control (RRC) connection using a non-transfer context approach. The context response message is also used to trigger the first network device to send an RRC connection restoration message to the terminal.

26. The method according to claim 25, wherein, The context response message includes a sixth piece of information, which indicates the tunnel endpoint assigned to the terminal. The tunnel endpoint is associated with a Data Radio Bearer (DRB) and the RRC connection recovery message includes the sixth piece of information.

27. The method according to claim 25 or 26, wherein, The context response message also includes a seventh message, which indicates that the context information of the terminal should not be migrated.

28. The method according to any one of claims 25 to 27, wherein, The second network device is the anchor device of the first network device, and the second network device stores the context information of the terminal.

29. A communication method applied to a communication system, the communication system including a first network device and a terminal, the method comprising: The terminal sends a first message to the first network device, the first message being used to request the establishment of a Radio Resource Control (RRC) connection with the first network device; The first network device sends one of the following to the terminal: an RRC connection recovery message; an RRC connection establishment message; wherein the first network device does not support the first security algorithm used by the terminal before entering the inactive state, the first security algorithm being used for security protection and integrity protection.

30. A communication device for performing the communication method according to any one of claims 1 to 15, 16 to 24, and 25 to 28.

31. A communication system comprising a first network device, a second network device, and a terminal, wherein the first network device is configured to implement the communication method of any one of claims 1 to 15, the terminal is configured to implement the communication method of any one of claims 16 to 24, and the second network device is configured to implement the communication method of any one of claims 25 to 28.

32. A storage medium storing instructions that, when executed on a communication device, cause the communication device to perform the communication method as described in any one of claims 1 to 15, 16 to 24, and 25 to 28.

33. A program product comprising at least one of a program and instructions, wherein the program and instructions, when executed by a communication device, implement the communication method according to any one of claims 1 to 15, 16 to 24, and 25 to 28.

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