Communication method and related apparatus

Abstract

The present application provides a communication method and a related apparatus, which can be applied to the technical field of communications. In the technical solution provided in the present application, upon determining that an interface connection with a second access network device is about to be disconnected, a first access network device sends a paging message or sends to a core network device a context of a first terminal device, the paging message being used for paging the first terminal device, and a radio network notification area of the second access network device covering a radio network notification area of the first terminal device. In the method, after a terminal device is released to an inactive state, the terminal device can subsequently return to a connected state normally, thereby avoiding the problem that the terminal device cannot transmit data.

Description

Communication method and related apparatus

[0001] This application claims priority from the Chinese patent application No. 202410870195.9 filed on June 28, 2024, and entitled "Communication method and related apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, and in particular, to a communication method and related apparatus. BACKGROUND

[0003] In the current communication system, after a terminal device is released to an inactive state by a first access network device, the terminal device can return to a connected state from the inactive state. For example, when there is downlink data to be sent to the terminal device, the first access network device will issue a paging message, and the terminal device will initiate access to the network and restore the radio resource control (RRC) connection after receiving the paging message. For another example, when the terminal device has uplink data, the terminal device performs cell reselection to access a second access network device, and the second access network device requests the terminal device context from the first access network device to restore the RRC connection.

[0004] However, in a non-terrestrial network (NTN) system, after the terminal device is released to the inactive state, it is difficult for the terminal device to return to the connected state, and thus the terminal device cannot transmit data. SUMMARY

[0005] The present application provides a communication method and related apparatus, so that after the terminal device is released to the inactive state, the terminal device can subsequently return to the connected state normally, thereby avoiding the problem that the terminal device cannot transmit data.

[0006] In a first aspect, the present application provides a communication method, which is applied to a first access network device. The method comprises: in a case where it is determined that an interface connection with a second access network device is about to be disconnected, sending a paging message or sending a context of a first terminal device to a core network device, the paging message being used for paging the first terminal device, and a radio network notification area of the second access network device containing a radio network notification area of the first terminal device.

[0007] In the method, the first access network device can be the access network device that last served the first terminal device before the first terminal device was released to the inactive state, such as a base station that last served the first terminal device.

[0008] Alternatively, the first access network device can be a base station that releases the first terminal device to the inactive state.

[0009] In the method, the second access network device can be any one of the access network devices within the wireless network notification area of the first terminal device, or alternatively, the second access network device can be any one of the access network devices containing the wireless network notification area of the first terminal device.

[0010] In the method, the first access network device can page the first terminal device first to return to the connected state, and then send the context of the first terminal device to the access network devices within the wireless network notification area of the first terminal device, so as to avoid the problem that the first access network device cannot page the first terminal device after the first access network device is disconnected from the access network devices within the wireless network notification area of the first terminal device, resulting in the first terminal device being unable to return to the connected state.

[0011] In addition, the first access network device can also transfer the context of the first terminal device to the core network device first, so that the access network device accessed by the first terminal device subsequently can obtain the context of the first terminal device from the core network device, thereby avoiding the problem that the access network device accessed by the first terminal device cannot obtain the context of the first terminal device from the first access network device after the first access network device is disconnected from the access network devices within the wireless network notification area of the first terminal device, resulting in the first terminal device being unable to return to the connected state.

[0012] In some possible implementation manners, the second access network device is included in a first access network device set, and the wireless network notification area of each access network device in the first access network device set contains the wireless network notification area of the first terminal device.

[0013] The sending of the paging message comprises separately distributing the paging message to each access network device in the first access network device set.

[0014] In this implementation manner, the first access network device can send the paging message to all the access network devices in the first access network device set, so as to ensure that the first terminal device can be paged and the situation that the first terminal device cannot be paged is avoided.

[0015] In some possible implementation manners, the sending of the paging message comprises sending the paging message to the second access network device.

[0016] This implementation manner can be applied to a scenario in which the terminal device moves in a small range.

[0017] In this implementation, the first access network device can not send the paging message to other access network devices except the second access network device, which is beneficial to reduce transmission overhead.

[0018] In some possible implementation, the method further includes: receiving first information, the first information indicating a wireless network notification area of each access network device in the first set of access network devices.

[0019] In this method, the first access network device can determine, through the first information, that the wireless network notification area of each access network device in the first set of access network devices contains the wireless network notification area of the first terminal device, and further determine the timing of sending the paging message by the first access network device, which is beneficial to avoid the problem that the first terminal device cannot return to the connected state.

[0020] In some possible implementation, the first information contains a wireless network notification area identifier of each access network device in the first set of access network devices, and the wireless network notification area identifier of each access network device contains a plurality of wireless network notification area identifiers, the plurality of wireless network notification area identifiers corresponding to a plurality of wireless network notification areas one by one.

[0021] The plurality of wireless network notification areas include a wireless network notification area corresponding to each access network device or a wireless network notification area corresponding to each serving cell of each access network device.

[0022] In this implementation, since the cell range of the access network device in the NTN communication system is large, the cell of one access network device is divided into a plurality of wireless network notification areas, that is, the wireless network notification areas in the cell of the access network device are subdivided, which is beneficial to bind the wireless network notification area with the ground and facilitate the location management of the terminal device.

[0023] In a second aspect, the present application provides a communication method, which is applied to a third access network device. The method can include: in the case that a first access network device and a second access network device are about to disconnect the interface connection or the first access network device and the second access network device have disconnected the interface connection, receiving a context of a first terminal device sent by the first access network device, a wireless network notification area of the second access network device containing a wireless network notification area of the first terminal device; sending a paging message or receiving second information, the paging message being used for paging the first terminal device, and the second information being used for requesting the context of the first terminal device; and sending the context of the first terminal device.

[0024] In the method, after the third access network device sends the paging message to the first terminal device, the first terminal device can first return to the connected state, and then the context of the first terminal device is transferred by the third access network device, or the access network device accessed by the first terminal device can obtain the context of the first UE from the third access network device before the third access network device moves to a farther distance. The problem that the first terminal device cannot return to the connected state is avoided when the third access network device cannot continue to push the context of the first terminal device after the first access network device is disconnected from the access network device within the wireless network notification area of the first terminal device.

[0025] In some possible implementation manners, the second access network device is included in the first access network device set, and the wireless network notification area of each access network device in the first access network device set includes the wireless network notification area of the first terminal device.

[0026] The third access network device belongs to the first access network device set, and the third access network device is connected to any one of the access network devices in the first access network device set except the third access network device; or the third access network device does not belong to the first access network device set, and the third access network device is connected to any one of the access network devices in the first access network device set.

[0027] In the method, the first access network device can obtain the identifier of the access network device connected to each of the plurality of access network devices, and then determine the third access network device connected to any one of the access network devices in the first access network device set, so that the access network device accessed by the first terminal device can obtain the context of the first terminal device from the third access network device, and the problem that the first terminal device cannot return to the connected state is avoided.

[0028] In some possible implementation manners, the context of the first terminal device includes one or more of the following information: a cell identifier under an access network device in the first access network device set and a truncated message authentication code corresponding to the cell under the access network device in the first access network device set, a security context corresponding to each access network device in the first access network device set, identifier information of the first terminal device, or information indicating the wireless network notification area of the first terminal device.

[0029] Any one of the access network devices in the first access network device set can be an access network device that the first terminal device can access subsequently.

[0030] The cells under the access network devices in the first set of access network devices can include each cell under each access network device in the first set of access network devices, and any cell under any access network device in the first set of access network devices can be a cell that the first terminal device can access later.

[0031] The first access network device sends, to the third access network device, the cell identifiers under each access network device in the first set of access network devices and the truncated message authentication codes corresponding to the cells under each access network device. After the first terminal device accesses any access network device in the first set of access network devices, the third access network device can determine the truncated message authentication code corresponding to the cell under the access network device accessed by the first terminal device from the truncated message authentication codes corresponding to the cells under each access network device in the first set of access network devices based on the cell identifier of the cell under the access network device accessed by the first terminal device, and then verify the first terminal device based on the truncated message authentication code corresponding to the cell under the access network device accessed by the first terminal device.

[0032] The first access network device sends, to the third access network device, the security context information corresponding to each access network device in the first set of access network devices. After the first terminal device accesses any access network device in the first set of access network devices, the third access network device can send the security context information corresponding to the access network device accessed by the first terminal device to the access network device accessed by the first terminal device, to ensure secure communication between the access network device accessed by the first terminal device and the first terminal device.

[0033] The identifier information of the first terminal device can include an inactive radio network temporary identifier (I-RNTI) of the first terminal device. The first access network device sends the identifier information of the first UE to the third access network device, to facilitate the third access network device to identify the first terminal device from a plurality of terminal devices.

[0034] The information for indicating the radio network notification area of the first terminal device can include a radio network notification area identifier of the first terminal device, for example, a radio network notification area code of the first terminal device. The first access network device sends the information for indicating the radio network notification area of the first terminal device to the third access network device, to facilitate the third access network device to determine the first set of access network devices and then determine the timing of sending the paging message.

[0035] In some possible implementation manners, the sending of the paging message includes sending the paging message to each access network device in the first set of access network devices, or sending the paging message to any access network device in the first set of access network devices in a case where it is determined that the any access network device will disconnect the interface connection.

[0036] In the method, after the third access network device sends the paging message, the first terminal device can return to the connected state first, thereby avoiding the problem that the first terminal device cannot return to the connected state.

[0037] In some possible implementation manners, before the second information is received, the method further includes: sending third information, the third information indicating that the third access network device has received the context of the first terminal device, and the third information containing identification information of the third access network device and identification information of the first terminal device.

[0038] In this implementation manner, the other access network devices can determine, based on the third information, that the third access network device has received the context of the first terminal device, and the access network device accessed by the first terminal device subsequently can obtain the context of the first terminal device from the third access network device, thereby ensuring that the first terminal device can return to the connected state, improving the efficiency of the access network device accessed by the first terminal device in obtaining the context of the first terminal device, and being beneficial to reducing the time required for the first terminal device to return to the connected state.

[0039] In some possible implementation manners, the method further includes: receiving first information, the first information indicating a radio network notification area of each access network device in the first set of access network devices.

[0040] In the method, the third access network device can determine, by using the first information, that the radio network notification area of each access network device in the first set of access network devices contains the radio network notification area of the first terminal device, and further determine the timing of sending the paging message by the third access network device, thereby being beneficial to avoiding the problem that the first terminal device cannot return to the connected state.

[0041] In some possible implementation manners, the first information contains a radio network notification area identifier of each access network device in the first set of access network devices, and the radio network notification area identifier of each access network device contains a plurality of radio network notification area identifiers, the plurality of radio network notification area identifiers corresponding to a plurality of radio network notification areas in a one-to-one manner.

[0042] The plurality of radio network notification areas include a radio network notification area corresponding to each access network device or a radio network notification area corresponding to each serving cell of each access network device.

[0043] In this implementation manner, since the cell range of the access network device in the NTN communication system is large, the cell of one access network device is divided into a plurality of radio network notification areas, that is, the radio network notification areas in the cell of the access network device are subdivided, thereby being beneficial to binding the radio network notification area with the ground and facilitating location management on the terminal device.

[0044] In some possible implementation manners, the method further includes: the second information includes a radio network notification area identifier of a target cell or a type of radio network notification area update initiated by the first terminal device, the target cell is a cell accessed by the first terminal device, and the type of radio network notification area update initiated by the first terminal device includes periodic radio network notification area update or aperiodic radio network notification area update.

[0045] The sending of the context of the first terminal device includes: if the radio network notification area of the first terminal device is not located in a radio network notification area indicated by the radio network notification area identifier of the target cell or the type of radio network notification area update initiated by the first terminal device is aperiodic radio network notification area update, the context of the first terminal device is sent.

[0046] This implementation manner is applicable to a scenario in which the radio network notification area identifier of each access network device in the first set of access network devices includes multiple radio network notification areas, and the multiple radio network notification areas are radio network notification areas corresponding to the each access network device.

[0047] Since the multiple radio network notification areas of the access network device include the radio network notification area corresponding to the access network device, the radio network notification area of the first terminal device is at a cell level, and the third access network device cannot determine whether the radio network notification area of the first terminal device is located in the multiple radio network notification areas of a certain access network device, and thus cannot determine whether to send the context of the first terminal device. When the second information includes the radio network notification area identifier of the target cell or the type of radio network notification area update initiated by the first terminal device, the third terminal device can determine whether to send the context of the first terminal device based on the second information, and thus it is beneficial to ensure that the third access network device can accurately send the context of the first terminal device.

[0048] In a third aspect, a communication method is provided. The method is applied to a first access network device. The method can include: in a case where it is determined that the first access network device and a second access network device are about to disconnect an interface connection or the first access network device and the second access network device have disconnected an interface connection, sending, to a third access network device, a context of a first terminal device, a radio network notification area of the second access network device including a radio network notification area of the first terminal device; and sending third information, the third information indicating that the third access network device has received the context of the first terminal device, the third information including identification information of the third access network device and identification information of the first terminal device.

[0049] In some possible implementation manners, the third access network device belongs to a first set of access network devices, a wireless network notification area of each access network device in the first set of access network devices contains a wireless network notification area of the first terminal device, and the third access network device is connected to any one of the access network devices in the first set of access network devices except the third access network device.

[0050] Alternatively, the third access network device does not belong to the first set of access network devices, and the third access network device is connected to any one of the access network devices in the first set of access network devices.

[0051] In some possible implementation manners, the context of the first terminal device contains one or more of the following information: a cell identifier under an access network device in the first set of access network devices and a truncated message authentication code corresponding to the cell under the access network device in the first set of access network devices, security context information corresponding to each access network device in the first set of access network devices, identification information of the first terminal device, or information used to indicate the wireless network notification area of the first terminal device.

[0052] In some possible implementation manners, the method further includes: receiving first information, the first information indicating a wireless network notification area of each access network device in a first set of access network devices.

[0053] In some possible implementation manners, the first information contains a wireless network notification area identifier of each access network device in the first set of access network devices, and the wireless network notification area identifier of each access network device contains a plurality of wireless network notification area identifiers, the plurality of wireless network notification area identifiers corresponding to a plurality of wireless network notification areas in one-to-one manner.

[0054] The plurality of wireless network notification areas include a wireless network notification area corresponding to each access network device or a wireless network notification area corresponding to each serving cell of each access network device.

[0055] In a fourth aspect, the present application provides a communication method, which is applied to a fourth access network device. The method can include: sending second information, the second information being used for requesting a context of a first terminal device, the second information containing a radio network notification area identifier of a target cell or a type of radio network notification area update initiated by the first terminal device, the target cell being a cell of the fourth access network device, the type of radio network notification area update initiated by the first terminal device containing a periodic radio network notification area update or an aperiodic radio network notification area update; and receiving the context of the first terminal device if the radio network notification area of the first terminal device is not located in a radio network notification area indicated by the radio network notification area identifier of the target cell or the type of radio network notification area update initiated by the first terminal device is the aperiodic radio network notification area update.

[0056] In some possible implementation manners, the method further includes: releasing the first terminal device to an inactive state after receiving the context of the first terminal device.

[0057] In a fifth aspect, the present application provides a communication apparatus, which can be used for the first access network device in the first aspect, the communication apparatus can be the first access network device, or a device (for example, a chip, a chip system, or a circuit) in the first access network device, or can be a logic module or software capable of realizing all or part of the functions of the first access network device. In a possible implementation, modules or units for realizing the method in the first aspect and any possible implementation manner of the first aspect are included. For example, modules or units corresponding to the method / operation / step / action described in the first aspect can be included, which can be hardware circuits, software, or a combination of hardware circuits and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0058] In a sixth aspect, the present application provides a communication apparatus, which can be used for the third access network device in the second aspect, the communication apparatus can be the third access network device, or a device (for example, a chip, a chip system, or a circuit) in the third access network device, or can be a logic module or software capable of realizing all or part of the functions of the third access network device. In a possible implementation, modules or units for realizing the method in the second aspect and any possible implementation manner of the second aspect are included. For example, modules or units corresponding to the method / operation / step / action described in the second aspect can be included, which can be hardware circuits, software, or a combination of hardware circuits and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0059] In a seventh aspect, the present application provides a communication apparatus, which can be used in the first access network device of the third aspect. The communication apparatus can be the first access network device, or a device (e.g., a chip, a chip system, or a circuit) in the first access network device, or a logic module or software capable of realizing all or part of the functions of the first access network device. In a possible implementation, the communication apparatus includes modules or units for implementing the methods in the third aspect and any possible implementation of the third aspect. For example, the communication apparatus can include modules or units corresponding to the methods / operations / steps / actions described in the third aspect, which can be hardware circuits, software, or a combination of hardware circuits and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0060] In an eighth aspect, the present application provides a communication apparatus, which can be used in the fourth access network device of the fourth aspect. The communication apparatus can be the fourth access network device, or a device (e.g., a chip, a chip system, or a circuit) in the fourth access network device, or a logic module or software capable of realizing all or part of the functions of the fourth access network device. In a possible implementation, the communication apparatus includes modules or units for implementing the methods in the fourth aspect and any possible implementation of the fourth aspect. For example, the communication apparatus can include modules or units corresponding to the methods / operations / steps / actions described in the fourth aspect, which can be hardware circuits, software, or a combination of hardware circuits and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0061] In a ninth aspect, the present application provides a communication apparatus, which includes a processor for executing a computer program (or computer executable instructions) stored in a memory and / or a logic circuit to enable the apparatus to perform the methods in any one of the first aspect to the fourth aspect and any possible implementation of the first aspect to the fourth aspect.

[0062] In a possible implementation, the apparatus further includes a memory.

[0063] In a possible implementation, the processor and the memory are integrated together.

[0064] In another possible implementation, the memory is located outside the communication apparatus.

[0065] In a possible implementation, the communication apparatus further includes a communication interface for the communication apparatus to communicate with other devices, such as transmitting or receiving data and / or signals. For example, the communication interface can be a transceiver, a circuit, a bus, a module, or other types of communication interfaces.

[0066] In a tenth aspect, the present application provides a computer readable storage medium storing computer programs or instructions for execution by a communication device, which when run on the communication device, cause the method of any one of the first aspect to the fourth aspect and any possible implementation thereof to be implemented.

[0067] In an eleventh aspect, the present application provides a computer program product containing instructions, which when run on a communication device, cause the method of any one of the first aspect to the fourth aspect and any possible implementation thereof to be implemented.

[0068] In a twelfth aspect, the present application provides a communication system comprising a first access network device. The first access network device is configured to implement the method of the first aspect and any possible implementation thereof.

[0069] Optionally, the communication system comprises a third access network device, the first access network device and a fourth access network device. The third access network device is configured to implement the method of the second aspect and any possible implementation thereof, the first access network device is configured to implement the method of the third aspect and any possible implementation thereof, and the fourth access network device is configured to implement the method of the fourth aspect and any possible implementation thereof.

[0070] It can be understood that the effects of the third aspect to the twelfth aspect can refer to the description of the first aspect and the second aspect, and will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0071] FIG. 1 is a schematic diagram of a communication system to which embodiments of the present application are applicable;

[0072] FIG. 2 is a schematic diagram of an open radio access network (O-RAN) system architecture;

[0073] FIG. 3 is a schematic diagram of a first NTN communication system architecture;

[0074] FIG. 4 is a schematic diagram of a second NTN communication system architecture;

[0075] FIG. 5 is a schematic diagram of a third NTN communication system architecture;

[0076] FIG. 6 is a schematic diagram of a fourth NTN communication system architecture;

[0077] FIG. 7 is a schematic diagram of a method flow for a terminal device to return from a deactivated state to a connected state;

[0078] FIG. 8 is a schematic diagram of a method flow for a network triggered terminal device to return from a deactivated state to a connected state;

[0079] FIG. 9 is a flowchart of a communication method according to an embodiment of the present application;

[0080] FIG. 10 is a flowchart of a communication method according to another embodiment of the present application;

[0081] FIG. 11 is a flowchart of a communication method according to yet another embodiment of the present application;

[0082] FIG. 12 is a flowchart of a communication method according to yet another embodiment of the present application;

[0083] FIG. 13 is a flowchart of a communication method according to yet another embodiment of the present application;

[0084] FIG. 14 is a flowchart of a method for a first access network device to send a context of a first terminal device to a fourth access network device according to an embodiment of the present application;

[0085] FIG. 15 is a flowchart of a method for a first base station to transmit a radio network notification area identifier of the first base station to a second base station according to an embodiment of the present application;

[0086] FIG. 16 is a flowchart of a method for a first base station to transmit an identifier of a base station connected to the first base station to a second base station according to an embodiment of the present application;

[0087] FIG. 17 is a schematic diagram of a communication apparatus according to an embodiment of the present application;

[0088] FIG. 18 is a schematic diagram of a communication apparatus according to another embodiment of the present application;

[0089] FIG. 19 is a schematic diagram of a communication apparatus according to yet another embodiment of the present application. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0091] In order to clearly describe the technical solutions in the embodiments of the present application, in the embodiments of the present application, the same items or similar items with basically the same functions and effects are distinguished by using “first”, “second”, etc. For example, the first information and the second information are only used to distinguish different information, and the order is not limited. Those skilled in the art can understand that the “first”, “second”, etc. do not limit the quantity and execution order, and the “first”, “second”, etc. also do not necessarily mean different.

[0092] In the embodiments of this application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and (or) c can represent: a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, and c can be single or multiple.

[0093] The technical solutions of the present application can be applied to a fifth generation (5th generation, 5G) communication system, such as a 5G new radio (new radio, NR) communication system, or to various communication systems evolved after 5G, such as future communication network systems. The method provided in the embodiments of the present application can also be applied to a wireless fidelity (wireless WiFi) system, a long range Internet of Things (long range, LoRa) system, or a vehicle Internet of Things system. The method provided in the embodiments of the present application can also be applied to a satellite communication system, or a non-terrestrial network (non-terrestrial networks, NTN) communication system. The satellite communication system can be integrated with the above-mentioned communication system, which is not limited in the present application.

[0094] In the following, the embodiments of the present application are described in detail in combination with the drawings.

[0095] In order to facilitate understanding of the embodiments of the present application, first, a communication system suitable for the embodiments of the present application is described in combination with FIG. 1. As shown in FIG. 1, the communication system includes a radio access network 100. The radio access network 100 can include at least one network device (such as 110a, 110b and 110c in FIG. 1), and can also include at least one terminal (such as 120a to 120g in FIG. 1).

[0096] In the communication system, the network device can include a wireless access network (RAN) device and a core network device. The terminal can be connected to the wireless access network device in a wireless manner. The wireless access network device is connected to the core network device in a wireless or wired manner. The core network device and the wireless access network device can be independent and different physical devices. Alternatively, the core network device and the wireless access network device can be integrated into the same physical device. Alternatively, the core network device and the wireless access network device can be integrated into a physical device. The terminal and the terminal can be connected to each other in a wired or wireless manner. The wireless access network device and the wireless access network device can be connected to each other in a wired or wireless manner. FIG. 1 is a schematic diagram. The communication system can also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in FIG. 1.

[0097] The wireless access network device can be a device with wireless transceiver function. The wireless access network device can be a device providing wireless communication function service, which is usually located at the network side, including but not limited to: a next-generation base station (gNodeB, gNB) in a 5G communication system, a base station in a future mobile communication system or an access node in a WiFi system, an evolved node B (eNB) in a long term evolution (LTE) system, a radio network controller (RNC), a home base station (for example, a home evolved NodeB or a home Node B, HNB), a baseband unit (BBU), a transmission reception point (TRP), a transmitting point (TP), etc.

[0098] The wireless access network device provides services for a cell. The user equipment uses the transmission resource of the cell to communicate with the base station. The cell can be a cell corresponding to the base station. The cell can belong to a macro base station or a base station corresponding to a small cell. The small cell can include a metro cell, a micro cell, a pico cell, a femto cell, etc.

[0099] The wireless access network device can also be a device assuming a base station function in device to device (D2D) communication, vehicle to everything (V2X) communication, unmanned plane communication, and machine communication. Optionally, the wireless access network device can be a satellite, a macro base station, a micro base station or an indoor station, a relay node or a donor node, a device providing wireless communication services for a user equipment, a wireless controller in a cloud radio access network (CRAN) scenario, a server, a relay station, a vehicle or a vehicle-mounted device, a wearable device, and a network device in future evolution networks, etc. For example, the wireless access network device in vehicle to everything (V2X) technology can be a road side unit (RSU).

[0100] In another possible scenario, multiple wireless access network devices cooperate to assist a terminal to implement wireless access, and different wireless access network devices respectively implement part of the functions of a base station. For example, the wireless access network device can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can be included in the same network element, such as a BBU. The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It can be understood that the wireless access network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the wireless access network device, or the CU can be divided into a network device in the core network device, which is not limited here.

[0101] The CU (or CU-CP and CU-UP), DU or RU can also have different names in different systems, but those skilled in the art can understand their meanings. For example, in an open-radio access network (O-RAN) system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0102] As an example, an O-RAN system architecture can be shown in FIG. 2. The O-RAN system architecture can include an O-RAN intelligent controller (RIC) and a radio access network device. In this example, the radio access network device is taken as a base station for example, the base station can be a base station supporting O-RAN functions, and supports base station-CU and base station-DU separation, the base station-CU and the base station-DU can communicate through an F1 interface, the RIC can be used to collect network information and perform necessary optimization tasks, and it communicates with the base station through an E2 interface, the RIC can interface the base station-CU and the base station-DU.

[0103] In the embodiments of the present application, the form of the radio access network device is not limited, and the device for realizing the function of the radio access network device can be the radio access network device; it can also be a device capable of supporting the radio access network device to realize the function, such as a chip system. The device can be installed in the radio access network device or used with the radio access network device. In the following, the radio access network device will be taken as a base station for example.

[0104] In this application, the terminal can also be referred to as a terminal device, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc., or a device used to provide voice or data connectivity to a user, which can also be an Internet of Things device. For example, the terminal device includes a handheld device with wireless connection function, a vehicle-mounted device, etc. At present, the terminal device can be: a mobile phone, a tablet computer, a notebook computer, a palm computer, a mobile internet device (MID), a wearable device (such as a smart watch, a smart bracelet, a pedometer, smart glasses, etc.), a vehicle-mounted device (such as a car, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a satellite terminal, a virtual reality (VR) device, an augmented reality (AR) device, a smart point of sale (POS) machine, a customer-premises equipment (CPE), a light terminal device (light UE), a reduced capability user equipment (REDCAP UE), a wireless terminal in industrial control, a smart home device (such as a refrigerator, a television, an air conditioner, an electricity meter, etc.), a smart robot, a mechanical arm, a workshop device, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, or a wireless terminal in a smart home, a flight device (such as a smart robot, a hot air balloon, a drone, an airplane), etc. The terminal device can also be a vehicle device, such as a whole vehicle device, a vehicle-mounted module, a vehicle-mounted chip, an on board unit (OBU), or a telematics box (T-BOX), etc. The terminal device can also be other devices with terminal functions, for example, the terminal device can also be a device that plays a terminal function in D2D communication.

[0105] In the embodiments of the present application, the device for implementing the function of the terminal can be a terminal, or a device capable of supporting the terminal to implement the function, such as a chip system, or a communication module, or a modem, etc., which can be installed in the terminal. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal.

[0106] In this application, the base station and the terminal can be fixed in position or mobile. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; and can also be deployed on aircraft, balloons and satellites in the air. Embodiments of the present application do not limit the application scenarios of the base station and the terminal.

[0107] The roles of the base station and the terminal can be relative, for example, the helicopter or the unmanned aerial vehicle 120c in FIG. 1 can be configured as a mobile base station, and for those terminals 120d that access the wireless access network 100 through 120c, the terminal 120c is a base station; but for the satellite 110a, 120c is a terminal, that is, 110a and 120c communicate through a wireless air interface protocol. Of course, 110a and 120c can also communicate through an interface protocol between base stations and base stations, at this time, relative to 110a, 120c is also a base station. Therefore, the base station and the terminal can be collectively referred to as a communication device, and 110a, 110b, 110c and 120a-120g in FIG. 1 can be referred to as communication devices with their respective corresponding functions, such as a communication device with base station function or a communication device with terminal function.

[0108] The base station and the terminal, the base station and the base station, and the terminal and the terminal can communicate through licensed spectrum, unlicensed spectrum, or both. The base station and the terminal, and the terminal and the terminal can communicate through sub-6G (sub 6G) spectrum, or through spectrum above 6G (above 6G) spectrum, or through both sub-6G spectrum and above 6G spectrum. Embodiments of the present application do not limit the spectrum resources used between the wireless access network device and the terminal.

[0109] In the NTN communication system, the wireless access network device can include a satellite, which can implement transparent payload transmission or regenerative payload transmission. Optionally, the wireless access network device in the NTN communication system can also include other devices, such as unmanned aerial vehicles, etc.

[0110] Hereinafter, the wireless access network device in the NTN communication system will be taken as an example for illustration.

[0111] FIG. 3 is a schematic diagram of a first NTN communication system architecture. The NTN communication system can be applicable to a transparent satellite scenario. In this example, the satellite supports functions such as radio frequency filtering, frequency conversion, and amplification, i.e., the satellite mainly acts as a relay (e.g., L1 relay) that regenerates physical layer signals and does not have other higher protocol layers.

[0112] In the NTN communication system, the UE communicates with the ground base station through a user-universal terrestrial radio access network (Uu) interface, and the satellite can implement transparent payload transmission between the user and the ground base station. The satellite and the NTN gateway can be considered as a radio frequency remote unit (RRU) of the ground base station, and implement transparent forwarding of signals. The forwarding of the satellite is transparent to the terminal device. The ground base station and the core network (CN) can communicate through a next generation (NG) interface, and exchange non-access stratum (NAS) signaling of the core network and service data of the UE through the NG interface.

[0113] The satellite can communicate with the NTN gateway through a wireless signal, and the NTN gateway and the ground base station can be connected through a wired connection.

[0114] Optionally, the NTN gateway in the embodiments of the present application can also be referred to as an NTN gateway.

[0115] FIG. 4 is a schematic diagram of a second NTN communication system architecture. The NTN communication system can be applicable to a regenerative satellite scenario without inter-satellite links (ISLs). In this example, the satellite has part or all of the functions of a radio access network device, which can be referred to as a satellite base station, and can provide radio access services and schedule radio resources for terminal devices accessing the network through the satellite base station.

[0116] In the NTN communication system, the satellite base station communicates with the UE through the Uu interface. The satellite base station and the CN can communicate through the NG interface, and the satellite base station and the core network can exchange NAS signaling and service data of the UE through the NG interface.

[0117] The link between the satellite base station and the NTN gateway can be referred to as a satellite radio interface (SRI) or a feeder link. In FIG. 4, the SRI can implement communication interaction between the satellite and the core network as part of the NG interface.

[0118] FIG. 5 is a schematic diagram of a third NTN communication system architecture. The NTN communication system can be applied to a regenerative satellite scenario with ISL. In this example, the satellite has part or all of the functions of a radio access network device, which can be referred to as a satellite base station, and can provide radio access services and schedule radio resources for terminal devices accessing the network through the satellite base station.

[0119] In the NTN communication system, the satellite base station has similar functions to the satellite base station shown in FIG. 4, which will not be described again here. The difference is that the satellite base station in the NTN network can establish an interface connection with another satellite base station, for example, an Xn interface. When a satellite base station cannot communicate with the NTN gateway, it can transmit data to another satellite base station through the Xn interface to transmit data to the ground through another satellite base station.

[0120] FIG. 6 is a schematic diagram of a fourth NTN communication system architecture. In this example, the satellite has the DU processing function of a base station. For example, the satellite can be a base station-distributed unit (gNB-DU), and the satellite can connect to the ground base station-centralized unit (gNB-CU) through the NTN gateway.

[0121] Optionally, in other NTN network architectures, the satellite can also have an integrated access and backhaul (IAB) function, and the satellite can act as an IAB node. In the NTN communication system, the satellite can not only deploy a DU, but also deploy an MT module. The satellite can perform backhaul with the ground base station based on the NR air interface of the MT module, without establishing a connection with the NTN gateway.

[0122] In existing communication systems, a UE can be released to an inactive state by a first access network device. In the inactive state, the RRC connection is released, but the UE and the first access network device both retain part of the UE context, and the NG interface protocol (NGAP) connection between the first access network device and the core network about the UE is not released, and the core network does not perceive the inactive state and considers that the UE is still under the service of the first access network device in the connected state. The first access network device here is the last access network device that serves the UE before the UE is released to the inactive state by the first access network device, which can be the last serving gNB (last serving gNB) of the UE.

[0123] After the UE is released to the inactive state by the first access network device, the UE can also return to the connected state from the inactive state.

[0124] For example, when the core network has downlink data to send to the terminal device, the core network transmits the downlink data to the first access network device, the first access network device sends a paging message within the radio network notification area (RAN Notification Area, RNA) of the UE, and the terminal device initiates access to the network and restores the radio resource control (RRC) connection after receiving the paging message.

[0125] The RNA represents a geographical area, and can be represented by a cell ID list or a RAN notification area code (RANAC).

[0126] For another example, when the terminal device has uplink data, the UE performs cell reselection to access the second access network device, the second access network device requests the UE context from the first access network device, and restores the RRC connection. The second access network device can be the base station where the UE is camped before cell reselection, or the base station where the UE initiates connection after cell reselection.

[0127] In some scenarios, the cell accessed by the UE during cell reselection can be located in the RNA of the UE, in which case the second access network device can be the first access network device, and the UE context request can not be performed.

[0128] In other scenarios, the cell accessed by the UE during cell reselection can not be located in the RNA of the UE, in which case the UE can initiate a RAN notification area update (RNAU) to restore the connection with the network, so as to migrate the UE context from the first access network device to the second access network device, thereby enabling the UE to return to the connected state from the deactivated state.

[0129] Optionally, the UE can also periodically initiate the RNAU to confirm the state of the UE to the network.

[0130] In the prior art, a method for returning the UE from the deactivated state to the connected state can be as shown in FIG. 7.

[0131] S701, the UE sends an RRC resume connection request message (RRCResumeRequest) to the second access network device, the RRC resume connection request message indicating that the reason for restoring the RRC connection is the RNAU. Correspondingly, the second access network device receives the RRC resume connection request message.

[0132] The RRC connection resume request message can include an inactive radio network temporary identifier (I-RNTI), and the I-RNTI can include an identifier of the first access network device and an identifier of the UE context.

[0133] The first access network device can send the I-RNTI to the UE when releasing the UE to the inactive state, and the I-RNTI can be carried in a SuspendConfig information element in an RRC release message.

[0134] In this embodiment, the UE sending the RRC connection resume request message can also be understood as the UE initiating an RNAU.

[0135] The second access network device sends a UE context request message to the first access network device to request the UE context, and the first access network device receives the UE context request message.

[0136] In this method, the second access network device can first determine the first access network device based on the identifier of the first access network device in the I-RNTI, and then send the UE context request message to the first access network device.

[0137] Optionally, the second access network device can establish an interface connection with the first access network device. For example, the second access network device can establish an Xn interface connection with the first access network device, and the second access network device can send the UE context request message to the first access network device based on the Xn interface.

[0138] In this method, the UE context request message can include the I-RNTI.

[0139] The first access network device determines whether to send the UE context to the second access network device.

[0140] Optionally, the first access network device can determine whether to send the UE context to the second access network device based on the type of the RNAU initiated by the UE.

[0141] The type of the RNAU initiated by the UE can include a periodic RNAU and an aperiodic RNAU. The periodic RNAU indicates that the RNAU is periodically initiated by the UE, and the aperiodic RNAU indicates that the RNAU is initiated when the cell accessed by the UE during cell reselection is not located in the RNA range of the UE.

[0142] Optionally, the UE context request message can further comprise a target cell ID of the second access network device, the target cell ID being used to indicate a cell of the second access network device accessed by the UE. The first access network device can determine whether the UE-initiated RNAU is a periodic RNAU or an aperiodic RNAU based on the target cell ID.

[0143] For example, assuming that the RNA of the UE is represented by a cell ID list, if the target cell ID is within the RNA range configured by the first access network device for the UE, the first access network device can determine that the UE-initiated RNAU is a periodic RNAU; if the target cell ID is not within the RNA range configured by the first access network device for the UE, the first access network device can determine that the UE-initiated RNAU is an aperiodic RNAU.

[0144] For another example, assuming that the RNA of the UE is represented by a RANAC, the first access network device can obtain the RANAC corresponding to each cell of the second access network device from the second access network device, and then determine the RANAC corresponding to the cell of the target cell ID based on the target cell ID, and then determine whether the RANAC is the same as the RANAC configured by the first access network device for the UE. If the RANAC is the same as the RANAC configured by the first access network device for the UE, the first access network device can determine that the UE-initiated RNAU is a periodic RNAU; if the RANAC is not the same as the RANAC configured by the first access network device for the UE, the first access network device can determine that the UE-initiated RNAU is an aperiodic RNAU.

[0145] When the UE-initiated RNAU is a periodic RNAU, the first access network device determines that the UE context can be sent to the second access network device or the UE context can not be sent to the second access network device.

[0146] When the UE-initiated RNAU is an aperiodic RNAU, the first access network device determines that the UE context can be sent to the second access network device.

[0147] In S704, the first access network device verifies whether the UE is legal.

[0148] In the method, the RRC connection resume request message sent by the UE to the second access network device can further carry a first short message authentication code (shortMAC-I), which can be calculated by the UE.

[0149] As an example, the UE can retain a source cell radio network temporary identifier (source C-RNTI), a source physical cell ID (source PCI) and a first key (e.g., Krrcint) when being released to the INACTIVE deactivated state. After re-accessing the second access network device, the UE can take the source C-RNTI, the source PCI and a target cell ID of the re-accessed second access network device as input parameters, and calculate a first truncated message authentication code based on the first key.

[0150] Optionally, the source C-RNTI herein can be a C-RNTI of the UE under the first access network device, and the source PCI herein can be a PCI of the UE under the first access network device.

[0151] The UE context request message sent by the second access network device to the first access network device can carry the first truncated message authentication code, the target cell ID and the I-RNTI. After receiving the UE context request message, the first access network device can determine the source C-RNTI, the source PCI and the first key of the UE based on the identifier of the UE context in the I-RNTI, and then calculate a second truncated message authentication code based on the source C-RNTI, the source PCI, the target cell ID and the first key. If the second truncated message authentication code is the same as the first truncated message authentication code, the first access network device determines that the UE is legitimate. If the second truncated message authentication code is different from the first truncated message authentication code, the first access network device determines that the UE is not legitimate.

[0152] S705, in the case of determining to send the UE context to the second access network device and the UE being legitimate, the first access network device sends the UE context to the second access network device.

[0153] Optionally, the first access network device can establish an interface connection with the second access network device. For example, the first access network device can establish an Xn interface connection with the second access network device, and then the first access network device can send the UE context to the second access network device based on the Xn interface.

[0154] In the method, if the UE performs the periodic RNAU but the first access network device decides not to send the UE context to the second access network device, the first access network device can update the source C-RNTI of the UE to the C-RNTI of the UE under the second access network device, and can update the source PCI of the UE to the PCI of the UE under the second access network device.

[0155] In the method, the C-RNTI of the UE under the second access network device and the PCI of the UE under the second access network device can be carried in the UE context request message.

[0156] In the method shown in FIG. 7, the procedure of the UE returning from the deactivated state to the connected state is triggered by the UE. Alternatively, the procedure of the UE returning from the deactivated state to the connected state can also be triggered by the network.

[0157] FIG. 8 is a schematic flow diagram of a method of the network triggering the UE returning from the deactivated state to the connected state.

[0158] S801, the first access network device sends a paging message to all access network devices within the RNA range of the UE, and the paging message is used to page the UE.

[0159] In the method, the I-RNTI of the UE can be carried in the paging message.

[0160] Alternatively, the first access network device can establish an interface connection with each of all access network devices within the RNA range of the UE. For example, the first access network device can establish an Xn interface connection with each of all access network devices within the RNA range of the UE, and the first access network device can send the paging message to each of all access network devices within the RNA range of the UE based on the Xn interface.

[0161] As an example, assuming that all access network devices within the RNA range of the UE include the second access network device and the third access network device, the first access network device can send the paging message to the second access network device and the third access network device respectively.

[0162] S802, all access network devices within the RNA range of the UE send the paging message to the UE. Correspondingly, the UE receives the paging message from the second access network device.

[0163] In the method, the second access network device is located within the RNA range of the UE, and the second access network device is the access network device currently camped by the UE.

[0164] S803, the UE sends a connection resumption request message to the second access network device. Correspondingly, the second access network device receives the RRC connection resumption request message.

[0165] S804, the second access network device sends a UE context request message to the first access network device, for requesting the UE context. Correspondingly, the first access network device receives the UE context request message.

[0166] S805, the first access network device determines whether to send the UE context to the second access network device.

[0167] S806, the first access network device verifies whether the UE is legal.

[0168] S807, in the case that the UE is determined to be legal, the first access network device sends the UE context to the second access network device.

[0169] In the method, S803 to S807 are consistent with the method flow shown in FIG. 7, which will not be described here.

[0170] In the method, the paging message and the UE context need to be sent through the communication interface. That is, when the UE returns from the deactivated state to the connected state, it is necessary to ensure that there is a communication interface between the access network devices within the same RNA range.

[0171] In some NTN communication systems, communication interfaces can be established between satellites. The communication interface can be established through an inter-satellite direct link or through a ground gateway. However, in the NTN communication system, when the distance between satellites is far, for example, there is no direct link between satellites, or the same ground gateway cannot be connected between satellites, the communication interface between satellites cannot be established. In this case, when there is downlink data to be sent to the UE, if the UE does not actively trigger the RNAU, the UE context is still on the first access network device, and when the first access network device moves to a far distance, the first access network device and the second access network device where the UE currently resides do not have a communication interface, and the first access network device cannot page the UE through the second access network device, thereby causing the UE to be unable to return to the connected state, and the UE cannot receive the downlink data. In addition, when the UE has uplink data, the second access network device currently accessed by the UE and the first access network device do not have a communication interface, so that the second access network device cannot obtain the UE context from the first access network device, thereby causing the UE to be unable to return to the connected state, and the core network cannot receive the uplink data.

[0172] Currently, the first access network device can actively push the UE context to another access network device, which is beneficial to avoid the problem that the UE cannot return to the connected state when the UE context is always on the first access network device. However, in this method, when the other access network device moves to a far distance, the problem that the UE cannot return to the connected state still occurs.

[0173] It is found through research that the reason why the UE cannot return to the connected state after the other access network device moves to a farther distance is that, based on security considerations, the other access network device cannot obtain the key of the first access network device and cannot authenticate the UE. In this way, after the first access network device pushes the UE context to the other access network device, if the other access network device is disconnected from the access network device within the RNA range of the UE before the UE returns to the connected state, the other access network device cannot push the UE context to other access network devices, and the other access network devices cannot obtain the UE context from the other access network device, thereby causing the UE to be unable to return to the connected state.

[0174] To this end, the present application can provide a technical solution for solving the problem that the UE in the NTN communication system cannot return to the connected state from the deactivated state.

[0175] In the technical solution of the present application, the first access network device can send a paging message to page the first UE before any one of the access network devices within the RNA range of the first UE is disconnected from the interface, and then send the context of the first UE.

[0176] In the method, the first access network device can page the first UE to make the first UE return to the connected state first, and then send the context of the first UE to the access network device within the RNA range of the first UE, thereby avoiding the problem that the first access network device cannot page the first UE after the first access network device is disconnected from the interface with the access network device within the RNA range of the first UE, and the first UE cannot return to the connected state.

[0177] Next, the present application will be described in detail in conjunction with FIGS. 9 to 11.

[0178] FIG. 9 is a flowchart of a communication method provided by an embodiment of the present application. The communication method can be applied to an NTN communication system, and the access network device in the NTN communication system can be a satellite.

[0179] S901, the first access network device sends a paging message when it is determined that the interface connection with the second access network device will be disconnected, and the paging message is used to page the first UE, and the RNA of the second access network device contains the RNA of the first UE.

[0180] In the method, the first access network device can be the last access network device that serves the first UE before the first UE is released to the deactivated state, such as the gNB that last serves the first UE.

[0181] Alternatively, the first access network device can be a gNB that releases the first UE to an access network device in the deactivated state.

[0182] In the method, the second access network device is included in the first access network device set, and the second access network device can be any one of the first access network device set. The first access network device set can include at least one access network device, and the RNA of each access network device in the at least one access network device includes the RNA of the first UE.

[0183] In the embodiments of the present application, for any one access network device, the access network device can obtain information indicating the RNA of another access network device from the another access network device.

[0184] The information indicating the RNA of the another access network device can include the RNA identifier of the another access network device.

[0185] In a possible implementation, for any one access network device, the RNA information of the access network device can include a plurality of RNA identifiers, the plurality of RNA identifiers correspond to a plurality of RNAs one-to-one, and each RNA identifier in the plurality of RNA identifiers is used to indicate the RNA corresponding to the RNA identifier.

[0186] In some examples, the plurality of RNAs can include the RNA corresponding to the access network device. That is, the granularity of the RNA of the access network device can be the access network device level, or the base station level.

[0187] In other examples, the plurality of RNAs can include the RNA corresponding to each serving cell of the access network device. That is, the granularity of the RNA of the access network device can be the cell level.

[0188] Optionally, the RNA identifier of the access network device can be indicated in the form of a list. For any one access network device, the RNA identifier of the access network device can correspond to an RNA identifier list (RNA list), and each RNA identifier list can include a plurality of RNA identifiers.

[0189] Optionally, the RNA identifier can be represented by RANAC. For example, for any one access network device, the RNA identifier list of the access network device can include a plurality of RANACs.

[0190] In the implementation, since the cell range of the access network device in the NTN communication system is large, the cell of one access network device is divided into multiple RNAs, that is, the RNAs in the cell of the access network device are subdivided, which is beneficial to binding the RNAs to the ground and facilitating the location management of the UE.

[0191] In another possible implementation, for any one access network device, the RNA identifier of the access network device can include one, which is used to indicate the RNA corresponding to the access network device.

[0192] Optionally, the information used to indicate the RNA of the access network device can be carried in a system information block (SIB). For example, the information used to indicate the RNA of the access network device can be carried in SIB1.

[0193] Optionally, the access network device can obtain the information used to indicate the RNA of another access network device from the other access network device through a communication interface. For example, the information used to indicate the RNA of the other access network device can be obtained from the other access network device through an Xn interface.

[0194] In the method, the first access network device can receive first information, which can indicate the RNA of each access network device in the first access network device set.

[0195] In the method, the first access network device can determine, through the first information, that the radio network notification area of each access network device in the first access network device set includes the radio network notification area of the first terminal device, and further determine the timing of sending the paging message by the first access network device, which is beneficial to avoiding the problem that the first terminal device cannot return to the connected state.

[0196] Optionally, the first information can include the RNA information of one or more access network devices. After receiving the first information, the first access network device can determine whether the RNA identifier in the RNA information of each access network device in the one or more access network devices includes the RNA identifier of the first UE, and then determine at least one access network device in the one or more access network devices whose RNA identifier in the RNA information includes the RNA of the first UE as the first access network device set.

[0197] Optionally, the number of the first information can be one or more, and one or more first information can correspond to one or more access network devices one by one. Each first information in the one or more first information can include the RNA information of the corresponding access network device.

[0198] In the method, the RNA information of the one or more access network devices can include the RNA information of each access network device in the first set of access network devices. Alternatively, the RNA information of each access network device in the first set of access network devices is a subset of the RNA information of the one or more access network devices.

[0199] In the method, the RNA information of each access network device in the first set of access network devices can include one or more RNA identifiers.

[0200] Alternatively, when the RNA information of each access network device in the first set of access network devices includes a plurality of RNA identifiers, the RNA information of each access network device can correspond to a list of RNA identifiers. In this case, the RNA of each access network device in the first set of access network devices includes the RNA of the first UE can be understood as that the RNA identifier of the first UE is included in the list of RNA identifiers of each access network device in the first set of access network devices.

[0201] Correspondingly, the RNA of the second access network device includes the RNA of the first UE can be understood as that the RNA identifier of the first UE is included in the list of RNA identifiers of the second access network device.

[0202] Alternatively, when the RNA information of each access network device in the first set of access network devices includes one RNA identifier, the RNA of each access network device in the first set of access network devices includes the RNA of the first UE can be understood as that the RNA identifier of each access network device in the first set of access network devices is the same as the RNA identifier of the first UE.

[0203] Correspondingly, the RNA of the second access network device includes the RNA of the first UE can be understood as that the RNA of the second access network device is the same as the RNA of the first UE.

[0204] In the method, a communication interface can be established between the first access network device and the second access network device. For example, the first access network device and the second access network device can establish a communication interface through an inter-satellite direct link. For another example, the first access network device and the second access network device can be connected to a same ground gateway station, and the first access network device and the second access network device can establish a communication interface based on the ground gateway station.

[0205] Alternatively, the first access network device can determine whether the interface connection between the first access network device and the second access network device will be disconnected based on ephemeris information. The ephemeris information can include parameters such as the position or the movement speed of the satellite.

[0206] Alternatively, the interface connection time and the interface disconnection time between the first access network device and the second access network device can be pre-configured based on the positions of the first access network device and the second access network device.

[0207] In a possible implementation, the first access network device can send the paging message to each access network device in the first set of access network devices respectively. Alternatively, the first access network device can send the paging message to all access network devices of the RNA containing the first UE respectively.

[0208] In this implementation, the communication method can be as shown in FIG. 10.

[0209] S1001, the first access network device determines that the interface connection with the access network device 1 is about to be disconnected, and sends a paging message to the access network device 1 and the access network device 2 respectively. Correspondingly, the access network device 1 and the access network device 2 can receive the paging message.

[0210] In this example, the first set of access network devices can include the access network device 1 and the access network device 2. The access network device 1 can be the second access network device.

[0211] Optionally, for any one of the access network device 1 and the access network device 2, the RNA of the access network device can include one or more.

[0212] Optionally, when the RNA of the access network device includes multiple RNAs, the multiple RNAs of the access network device can include the RNA corresponding to the access network device or the RNA of each serving cell of the access network device.

[0213] S1002, the access network device 1 and the access network device 2 send the paging message to the first UE respectively. Correspondingly, the first UE receives the paging message sent by the access network device 2.

[0214] In this method, the paging message received by the first UE can be sent by the access network device in which the first UE currently resides. In this embodiment, it is assumed that the first UE currently resides in the access network device 2, and the first UE receives the paging message sent by the access network device 2.

[0215] S1003, the first UE establishes a connection with the access network device 2.

[0216] S1004, the access network device 2 sends second information to the first access network device, and the second information is used to request the context of the first UE. Correspondingly, the first access network device receives the second information.

[0217] Optionally, the access network device 2 can first receive the RRC connection resume request message from the first UE. After receiving the RRC connection resume request message from the first UE, the access network device 2 sends the second information to the first access network device.

[0218] S1005, the first access network device sends the context of the first UE to the access network device 2. Correspondingly, the access network device 2 receives the context of the first UE.

[0219] In the method, before the first access network device sends the context of the first UE to the access network device 2, the first UE can be verified. In the case that the first UE is verified successfully, the context of the first UE is sent.

[0220] In the method, after the access network device 2 receives the context of the first UE, the first UE can be released to the inactive state.

[0221] Since there is no actual service generated at present for the first UE, after the first UE is released to the inactive state, the resource and power consumption of the first UE can be saved.

[0222] In the embodiment shown in FIG. 10, the first UE currently resides under the access network device 2 is taken as an example for description.

[0223] Optionally, in another embodiment, the first UE can currently reside under the access network device 1. In this case, the first UE can receive the paging message sent by the access network device 1, and the access network device 1 can obtain the context of the first UE from the first access network device. The method that the access network device 1 obtains the context of the first UE from the first access network device can refer to S1004 and S1005, which will not be described herein.

[0224] In the implementation, the first access network device can send the paging message to all the access network devices in the access network device set of the first UE, so that the first UE can be paged and the situation that the first UE cannot be paged can be avoided.

[0225] Optionally, in the implementation, the RNA of the second access network device can contain the RNA of multiple UEs. In this case, when the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device can send the paging message of each UE to all the access network devices in the access network device set corresponding to the UE. The RNA of each access network device in the access network device set corresponding to each UE contains the RNA of the UE.

[0226] For example, it is assumed that the RNA of the second access network device contains the RNA of the first UE and the RNA of the second UE, the set of access network devices corresponding to the first UE is the first set of access network devices, and the set of access network devices corresponding to the second UE is the second set of access network devices. When the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device can send a paging message for paging the first UE to all access network devices in the first set of access network devices, and can send a paging message for paging the second UE to all access network devices in the second set of access network devices.

[0227] In another possible implementation, the first access network device can send a paging message to the second access network device.

[0228] In this implementation, the communication method can be as shown in FIG. 11.

[0229] S1101, when the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device sends a paging message to the second access network device. Correspondingly, the second access network device receives the paging message.

[0230] In this example, the first set of access network devices can contain the second access network device.

[0231] Optionally, for the second access network device, the RNA of the second access network device can contain one or more.

[0232] Optionally, when the RNA of the second access network device contains multiple RNAs, the multiple RNAs of the second access network device can include the RNA corresponding to the second access network device or the RNA of each serving cell of the second access network device.

[0233] S1102, the second access network device sends a paging message to the first UE. Correspondingly, the first UE receives the paging message.

[0234] In this method, the paging message received by the first UE can be sent by the access network device currently camped by the first UE. In this embodiment, it is assumed that the first UE currently camps under the second access network device, and the first UE receives the paging message sent by the second access network device.

[0235] S1103, the first UE establishes a connection with the second access network device.

[0236] S1104, the second access network device sends second information to the first access network device, and the second information is used to request the context of the first UE. Correspondingly, the first access network device receives the second information.

[0237] Optionally, the method that the second access network device sends the second information to the first access network device can refer to the related content of the foregoing S1004 that the access network device 2 sends the second information to the first access network device, and details are not described herein again.

[0238] S1105, the first access network device sends the context of the first UE to the second access network device. Correspondingly, the second access network device receives the context of the first UE.

[0239] In the method, the method that the first access network device sends the context of the first UE to the second access network device can also refer to the related content of S1005 that the first access network device sends the context of the first UE to the access network device 2, and details are not described herein again.

[0240] In the method, after the second access network device receives the context of the first UE, the first UE can also be released to the inactive state.

[0241] Since no actual service is generated at present for the first UE, after the first UE is released to the inactive state, the resource and power consumption of the first UE can be saved.

[0242] In the implementation manner, the implementation manner can be applied to a scenario in which the UE moves in a small range.

[0243] In the implementation manner, the first access network device can not send the paging message to other access network devices except the second access network device, which is beneficial to reduce the transmission overhead.

[0244] Optionally, in the implementation manner, the RNA of the second access network device can include the RNAs of multiple UEs. In this case, when the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device can send the paging message for paging each UE of the multiple UEs to the second access network device respectively.

[0245] For example, it is assumed that the RNA of the second access network device includes the RNA of the first UE and the RNA of the second UE. When the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device can send the paging message for paging the first UE and the paging message for paging the second UE to the second access network device.

[0246] In the method, the first access network device can page the first UE first to return to the connected state, and then send the context of the first UE to the access network device within the RNA range of the first UE, so as to avoid the problem that the first access network device cannot page the first UE after the first access network device disconnects the interface connection with the access network device within the RNA range of the first UE, and the first UE cannot return to the connected state.

[0247] In the communication method, the first access network device can further send the context of the first UE to the core network device when determining that the interface connection with the second access network device is about to be disconnected.

[0248] The first access network device can further send a key of the first access network device, such as Krrcint of the first access network device, to the core network device.

[0249] Optionally, the key of the first access network device can be carried in the context of the first UE.

[0250] Optionally, the RNA of the second access network device can contain the RNAs of multiple UEs. In this case, when the first access network device determines that the interface connection with the second access network device is about to be disconnected, the first access network device can send the context of each UE of the multiple UEs to the core network device.

[0251] In the method, the first access network device can further transfer the context of the first UE to the core network device in advance, so that the access network device accessed by the first UE subsequently can obtain the context of the first UE from the core network device, thereby avoiding the problem that the access network device accessed by the first UE cannot obtain the context of the first UE from the first access network device after the first access network device disconnects the interface connection with the access network device within the RNA range of the first UE, resulting in the first UE being unable to return to the connected state.

[0252] In the technical solution of the present application, the first access network device can further push the context of the first UE to another access network device before or after disconnecting the interface connection with any one of the access network devices within the RNA range of the first UE, and then the another access network device sends a paging message to the first UE, or the access network device accessed by the first UE can obtain the context of the first UE from the first access network device before the another access network device moves to a farther distance.

[0253] In the method, the another access network device is an access network device within the RNA range of the first UE, and the another access network device and the first access network device have an interface connection.

[0254] In the method, after the another access network device sends a paging message to the first UE, the first UE can first return to the connected state, and then the another access network device transfers the context of the first UE, or the access network device accessed by the first UE can obtain the context of the first UE from the another access network device before the another access network device moves to a farther distance. This avoids the problem that the first UE cannot return to the connected state when the another access network device cannot continue to push the context of the first UE after the first access network device disconnects the interface connection with the access network device within the RNA range of the first UE.

[0255] Next, the technical solution will be described in detail in combination with FIG. 12 to FIG. 14.

[0256] FIG. 12 is a flowchart of a communication method provided by another embodiment of the present application. The communication method can be applied to an NTN communication system, and the access network device in the NTN communication system can be a satellite.

[0257] In S1201, the first access network device sends the context of the first UE to a third access network device in a case where it is determined that the interface connection with the second access network device is about to be disconnected or has been disconnected, and the RNA of the second access network device contains the RNA of the first UE.

[0258] In the method, the first access network device can be the access network device that last served the first UE before releasing the first UE to the inactive state, such as the gNB that last served the first UE.

[0259] Alternatively, the first access network device can be the access network device that released the first UE to the inactive state, such as the gNB that released the first UE to the inactive state.

[0260] In the method, the second access network device is included in a first access network device set, and the second access network device can be any one of the access network devices in the first access network device set. The first access network device set can include at least one access network device, and the RNA of each access network device in the at least one access network device contains the RNA of the first UE.

[0261] In the embodiments of the present application, for any one access network device, the access network device can obtain information for indicating the RNA of another access network device from the another access network device.

[0262] The information for indicating the RNA of the another access network device can include the RNA identifier of the another access network device.

[0263] In a possible implementation, for any one access network device, the RNA information of the access network device can include a plurality of RNA identifiers, the plurality of RNA identifiers correspond to a plurality of RNAs one by one, and each RNA identifier in the plurality of RNA identifiers is used to indicate the RNA corresponding to the RNA identifier.

[0264] In some examples, the plurality of RNAs can include the RNA corresponding to the access network device. That is, the granularity of the RNA of the access network device can be the access network device level, or the base station level.

[0265] In some examples, the plurality of RNAs can include an RNA corresponding to each serving cell of the access network device. That is, the granularity of the RNA of the access network device can be cell level.

[0266] Optionally, the RNA identifier of the access network device can be indicated by a list. For any access network device, the RNA identifier of the access network device can correspond to an RNA list, and each RNA list can include a plurality of RNA identifiers.

[0267] Optionally, the RNA identifier can be represented by a RANAC. For example, for any access network device, the RNA identifier list of the access network device can include a plurality of RANACs.

[0268] In this implementation, since the cell range of the access network device in the NTN communication system is large, the cell of the access network device is divided into a plurality of RNAs, that is, the RNAs in the cell of the access network device are subdivided, which is conducive to binding the RNA to the ground and facilitating the location management of the UE.

[0269] In another possible implementation, for any access network device, the RNA identifier of the access network device can include one, and the RNA identifier is used to indicate the RNA corresponding to the access network device.

[0270] Optionally, the information for indicating the RNA of the access network device can be carried in a system information block (SIB). For example, the information for indicating the RNA of the access network device can be carried in SIB1.

[0271] Optionally, the access network device can obtain the information for indicating the RNA of the other access network device from the other access network device through a communication interface. For example, the information for indicating the RNA of the other access network device can be obtained from the other access network device through an Xn interface.

[0272] Optionally, the first access network device can receive first information, and the first information can indicate the RNA of each access network device in the first access network device set.

[0273] In a possible implementation, the first information can include the RNA information of one or more access network devices. After receiving the first information, the first access network device can determine whether the RNA identifier corresponding to the RNA information of each access network device in the one or more access network devices includes the RNA of the first UE, and then determine at least one access network device in the one or more access network devices whose RNA identifier includes the RNA of the first UE as the first access network device set.

[0274] Optionally, the number of the first information can be one or more, and the one or more first information can correspond to one or more access network devices one by one, and each of the one or more first information can contain RNA information of the corresponding access network device.

[0275] In the method, the RNA information of the one or more access network devices can contain RNA information of each access network device in the first set of access network devices. Alternatively, the RNA information of each access network device in the first set of access network devices is a subset of the RNA information of the one or more access network devices.

[0276] Optionally, in a possible implementation, for any one access network device, the RNA information of the access network device can contain a plurality of RNA identifiers, the plurality of RNA identifiers correspond to a plurality of RNAs one by one, and each of the plurality of RNA identifiers is used to indicate the RNA corresponding to each RNA identifier.

[0277] In some examples, the plurality of RNAs can include the RNA corresponding to each access network device. That is, the granularity of the RNA of the access network device can be device level.

[0278] In other examples, the plurality of RNAs can include the RNA corresponding to each serving cell of each access network device. That is, the granularity of the RNA of the access network device can be cell level.

[0279] Optionally, the RNA identifier of the access network device can be indicated by a list. For any one access network device, the RNA identifier of the access network device can correspond to an RNA identifier list (RNA list), and each RNA identifier list can contain a plurality of RNA identifiers.

[0280] Optionally, the RNA identifier can be represented by RANAC. For example, for any one access network device, the RNA identifier list of the access network device can contain a plurality of RANACs.

[0281] In the implementation, the RNA of each access network device in the first set of access network devices containing the RNA of the first UE can be understood as: the RNA identifier list of each access network device in the first set of access network devices containing the RNA of the first UE.

[0282] Correspondingly, the RNA of the second access network device containing the RNA of the first UE can be understood as: the RNA identifier list of the second access network device containing the RNA of the first UE.

[0283] In another possible implementation, for any one access network device, the RNA identifier of the access network device can contain one used to indicate the RNA to which the access network device corresponds.

[0284] In this implementation, the RNA of each access network device in the first set of access network devices containing the RNA of the first UE can be understood as that the RNA of each access network device in the first set of access network devices is the same as the RNA of the first UE.

[0285] Correspondingly, the RNA of the second access network device containing the RNA of the first UE can be understood as that the RNA of the second access network device is the same as the RNA of the first UE.

[0286] In this method, a communication interface can be established between the first access network device and the second access network device. For example, the first access network device and the second access network device can establish a communication interface through an inter-satellite direct link. For another example, the first access network device and the second access network device can be connected to a same ground gateway station, and the first access network device and the second access network device can establish a communication interface based on the ground gateway station.

[0287] Optionally, the first access network device can determine whether the interface connection between the first access network device and the second access network device is to be disconnected based on ephemeris information. The ephemeris information can contain parameters such as the position or the movement speed of the satellite.

[0288] Optionally, the interface connection time and the interface disconnection time between the first access network device and the second access network device can be preconfigured based on the positions of the first access network device and the second access network device.

[0289] In this method, the third access network device is a node receiving the context of the first UE. In some embodiments, the third access network device can also be referred to as a receiving node.

[0290] Optionally, in some embodiments, the third access network device can belong to the first set of access network devices, or in other words, the third access network device can be contained in the first set of access network devices. In this case, the third access network device can have an interface connection with any one access network device in the first set of access network devices except the third access network device.

[0291] Optionally, in some other embodiments, the third access network device can not belong to the first set of access network devices. In this case, the third access network device can have an interface connection with any one access network device in the first set of access network devices.

[0292] Optionally, for any two access network devices, the two access network devices can interact with the identifiers of the access network devices with which the two access network devices have interface connections through an interface.

[0293] As an example, it is assumed that the network system comprises access network device 1, access network device 2, access network device 3 and access network device 4. Among them, the access network device 1 is in interface connection with the access network device 2 and the access network device 3, and the access network device 2 is in interface connection with the access network device 1, the access network device 3 and the access network device 4. Then the access network device 1 can send the identifier of the access network device 2 and the identifier of the access network device 3 to the access network device 2, and the access network device 2 can send the identifier of the access network device 1, the identifier of the access network device 3 and the identifier of the access network device 4 to the access network device 1.

[0294] In the method, the first access network device can obtain the identifier of the access network device in interface connection with each of the plurality of access network devices from the each of the plurality of access network devices, and further determine the third access network device in interface connection with any one of the first set of access network devices, so that the access network device accessed by the first UE subsequently can obtain the context of the first UE from the third access network device, avoiding the problem that the first UE cannot return to the connected state subsequently.

[0295] In the method, the context of the first UE can comprise one or more of the following information: the cell identifier under the access network device in the first set of access network devices and the truncated message authentication code corresponding to the cell under the access network device in the first set of access network devices, the security context information corresponding to each of the access network devices in the first set of access network devices, the identifier information of the first UE, or the information indicating the RNA of the first UE.

[0296] Among them, any one of the access network devices in the first set of access network devices can be the access network device that the first UE can access subsequently.

[0297] The cells under the access network devices in the first set of access network devices can comprise each cell under each of the access network devices in the first set of access network devices, and any one of the cells under any one of the access network devices in the first set of access network devices can be the cell that the first UE can access subsequently.

[0298] Optionally, the truncated message authentication code corresponding to the cells under the access network devices in the first set of access network devices can comprise the truncated message authentication code corresponding to the cells under each of the access network devices in the first set of access network devices, and the truncated message authentication code corresponding to the cells under each of the access network devices in the first set of access network devices is calculated based on the cell identifier of the each cell by the first access network device.

[0299] The first access network device sends, to the third access network device, cell identities under each access network device in the first set of access network devices and corresponding truncated message authentication codes of the cells under each access network device. After the first UE accesses any access network device in the first set of access network devices, the third access network device can determine the corresponding truncated message authentication code of the cell under the access network device accessed by the first UE from the corresponding truncated message authentication codes of the cells under each access network device in the first set of access network devices based on the cell identity of the cell under the access network device accessed by the first UE, and then verify the first UE based on the corresponding truncated message authentication code of the cell under the access network device accessed by the first UE.

[0300] The security context information corresponding to each access network device in the first set of access network devices can include at least one of a key (e.g., K NG-RAN * ) and a next-hop chaining count (NCC) of each access network device in the first set of access network devices.

[0301] For any access network device, the key and the next-hop chaining count of the access network device can be calculated based on the PCI and the frequency of the access network device.

[0302] Specifically, the security context information corresponding to each access network device can include a list, which can include one or more parameters, and each parameter in the one or more parameters can include a combination of a PCI of a target cell and a frequency of the target cell to which the first UE can access and at least one of a key and a NCC corresponding to the combination of the PCI of the target cell and the frequency of the target cell.

[0303] The first access network device sends, to the third access network device, the security context information corresponding to each access network device in the first set of access network devices. After the first UE accesses any access network device in the first set of access network devices, the third access network device can send the security context information corresponding to the access network device accessed by the first UE to the access network device accessed by the first UE, to ensure secure communication between the access network device accessed by the first UE and the first UE.

[0304] The identification information of the first UE can include an I-RNTI of the first UE. The first access network device sends, to the third access network device, the identification information of the first UE, to facilitate the third access network device to identify the first UE from a plurality of UEs.

[0305] The information for indicating the RNA of the first UE can include an RNA identifier of the first UE, for example, can include an RANAC of the first UE.

[0306] S1202, the third access network device sends a paging message, where the paging message is used for paging the first UE.

[0307] In the method, the paging message can be sent by the third access network device actively.

[0308] In a possible implementation, the third access network device can send the paging message to each access network device in the first access network device set after receiving the context of the first UE.

[0309] In another possible implementation, the third access network device can send the paging message to any one of the first access network device set in a case where it is determined that the interface connection with the any one of the first access network device set is about to be disconnected.

[0310] In the two implementations, the third access network device needs to determine the first access network device set before sending the paging message.

[0311] Optionally, the context of the first UE can include information used for indicating the RNA of the first UE, and the third access network device can further receive information used for indicating the RNA of the plurality of access network devices from the plurality of access network devices respectively, and the third access network device can determine the first access network device set based on the information used for indicating the RNA of the first UE and the information used for indicating the RNA of the plurality of access network devices.

[0312] Optionally, the third access network device can further receive the first access network device set sent by the first access network device.

[0313] Optionally, the third access network device can further receive information used for indicating the RNA of the plurality of access network devices from the plurality of access network devices respectively, and then the third access network device can determine the first access network device set as the access network device set having the same or intersecting RNA as the third access network device.

[0314] The RNA of the access network device can refer to related content in the embodiment shown in FIG. 9, which is not described herein again.

[0315] As an example, the third access network device can page the first UE through a fourth access network device in the first access network device set, and the fourth access network device is the access network device camped by the first UE. Then, the first UE accesses the fourth access network device, and the fourth access network device can send the second information to the third access network device. After receiving the second information from the fourth access network device, the third access device can send the context of the first UE to the fourth access network device.

[0316] Optionally, the fourth access network device can send the second information to the third access network device after receiving the RRC connection resume request message sent by the first UE.

[0317] The method for the fourth access network device to send the second information to the third access network device can refer to the related content of the access network device 2 sending the second information to the first access network device in the embodiment shown in FIG. 10, which will not be repeated here.

[0318] The method for the third access network device to send the context of the first UE to the fourth access network device can refer to the step of the first access network device sending the context of the first UE to the access network device 2 in the embodiment shown in FIG. 10, which will not be repeated here.

[0319] In the method, after the third access network device sends the paging message to the first UE, the first UE can first return to the connected state, and then the third access network device transfers the context of the first terminal device. This avoids the problem that the first UE cannot return to the connected state when the third access network device cannot continue to push the context of the first UE after the first access network device disconnects the interface connection with the access network device within the wireless network notification area range of the first UE.

[0320] FIG. 13 is a flow diagram of a communication method provided by another embodiment of the present application. The communication method can be applied to an NTN communication system, and the access network device in the NTN communication system can be a satellite.

[0321] S1301, the first access network device sends the context of the first UE to the third access network device in a case where it is determined that the interface connection with the second access network device is about to be disconnected or has been disconnected, and the RNA of the second access network device contains the RNA of the first UE.

[0322] In the method, the first access network device sending the context of the first UE to the third access network device can refer to the related content in S1301, which will not be repeated here.

[0323] S1302, the fourth access network device sends second information to the third access network device, and the second information is used to request the context of the first UE. Correspondingly, the third access network device receives the second information.

[0324] In the method, the fourth access network device can be an access network device accessed by the first UE.

[0325] In the method, after the third access network device receives the context of the first UE, all access network devices in the first access network device set can receive third information, the third information indicating that the third access network device has received the context of the first UE. In this case, after the first UE accesses the fourth access network device, the fourth access network device can send second information to the third access network device.

[0326] The third information can include identification information (for example, gNB ID and / or IP address) of the third access network device and identification information (for example, I-RNTI) of the first UE.

[0327] Optionally, the third information can be sent by the first access network device or by the third access network device.

[0328] For example, after the first access network device sends the context of the first UE to the third access network device, the first access network device can send the third information to all access network devices in the first access network device set respectively.

[0329] This example can be applied to the case where the first access network device and the second access network device are about to disconnect the interface connection.

[0330] For another example, after the third access network device receives the context of the first UE, the third access network device can send the third information to all access network devices in the first access network device set respectively.

[0331] In this implementation, the fourth access network device can be included in the first access network device set.

[0332] Optionally, the fourth access network device can send the second information to the third access network device after receiving the RRC connection resume request message sent by the first UE, that is, the fourth access network device can send the second information to the third access network device after receiving the RNAU initiated by the first UE.

[0333] Optionally, if the fourth access network device has multiple RNAs and the multiple RNAs of the fourth access network device include the RNA corresponding to the fourth access network device, the second information can further include the RNA identifier of the target cell or the type of the RNAU initiated by the first UE.

[0334] The target cell can be a cell accessed by the first UE, that is, a cell of the fourth access network device accessed by the first UE.

[0335] The type of the RNAU initiated by the first UE can include a periodic RNAU or an aperiodic RNAU.

[0336] Optionally, the type of the RNAU initiated by the first UE can be carried in the RRC resume connection request message, and the fourth access network device can determine the type of the RNAU initiated by the first UE based on the received RRC resume connection request message.

[0337] Optionally, the first access network device configures a reasonable periodic RNAU period for the UE, to ensure that the UE performs a periodic RNAU before the third access network device receives the context and before the third access network device disconnects the interface connection with the access network devices in the first access network set.

[0338] Optionally, if the RNA of the fourth access network device contains one, or the RNA of the fourth access network device contains multiple, and the multiple RNAs of the fourth access network device include the RNA corresponding to each serving cell of the fourth access network device, the second information can refer to the related content of the UE context request message in the prior art, which will not be described here.

[0339] In the method, the other access network devices can determine that the third access network device has received the context of the first UE based on the third information, and the fourth access network device can obtain the context of the first UE from the third access network device, which can improve the efficiency of the access network device accessed by the first UE in obtaining the context of the first UE, and is conducive to reducing the time required for the first UE to return to the connected state.

[0340] S1303, the third access network device sends the context of the first UE to the fourth access network device. Correspondingly, the fourth access network device receives the context of the first UE.

[0341] In the method, before the third access network device sends the context of the first UE to the fourth access network device, it can also determine whether to send the context of the first UE to the fourth access network device and verify the first UE. Only when it is determined to send the context of the first UE to the fourth access network device and the first UE is verified successfully, the context of the first UE is sent.

[0342] Optionally, if the RNA of the fourth access network device contains multiple, and the multiple RNAs of the fourth access network device include the RNA corresponding to the fourth access network device, the third access network device can determine whether to send the context of the first UE to the fourth access network device based on the RNA identifier of the target cell or the type of the RNAU initiated by the first UE contained in the second information.

[0343] Optionally, after receiving the second information, the third access network device determines to transfer the context of the first UE to the fourth access network device, and does not need to determine whether to transfer the context based on the RNA information.

[0344] Optionally, if the RNA of the fourth access network device contains multiple RNAs and the multiple RNAs of the fourth access network device include the RNA corresponding to the fourth access network device (i.e., the multiple RNAs of the fourth access network device are device-level RNAs rather than cell-level RNAs), the method in which the third access network device sends the context of the first UE to the fourth access network device can be as shown in FIG. 14.

[0345] S1401. The first UE sends an RRC connection resume request message to the fourth access network device, where the RRC connection resume request message indicates that the reason for resuming the RRC connection is an RNAU. Correspondingly, the fourth access network device receives the RRC connection resume request message.

[0346] Optionally, the RRC connection resume request message can contain indication information used to indicate the type of the RNAU initiated by the first UE, where the type of the RNAU includes a periodic RNAU and an aperiodic RNAU.

[0347] S1402. The fourth access network device sends second information to the third access network device, where the second information is used to request the context of the first UE. Optionally, the second information contains the RNA identifier of the target cell or the type of the RNAU initiated by the first UE. Correspondingly, the third access network device receives the second information.

[0348] S1403. The third access network device can determine whether to send the context of the first UE to the fourth access network device based on the second information.

[0349] For example, assuming that the second information contains the RNA identifier of the target cell, if the RNA of the first UE is located in the RNA indicated by the RNA identifier of the target cell, the third access network device determines not to send the context of the first UE to the fourth access network device; if the RNA of the first UE is not located in the RNA indicated by the RNA identifier of the target cell, the third access network device determines to send the context of the first UE to the fourth access network device.

[0350] For another example, assuming that the second information contains the type of the RNAU initiated by the first UE, if the type of the RNAU initiated by the first UE is a periodic RNAU, the third access network device determines not to send the context of the first UE to the fourth access network device; if the type of the RNAU initiated by the first UE is an aperiodic RNAU, the third access network device determines to send the context of the first UE to the fourth access network device.

[0351] Optionally, if the RNA of the fourth access network device contains one, or the RNA of the fourth access network device contains multiple, and the multiple RNAs of the fourth access network device include the RNA of the fourth access network device, the third access network device determines whether to send the context of the first UE to the fourth access network device can refer to the method of the third access network device determining whether to send the context of the UE in the prior art, which will not be described here.

[0352] S1404, the third access network device verifies whether the first UE is legal.

[0353] Optionally, the method of the third access network device verifying the first UE can also refer to the method of the first access network device verifying the UE in the prior art, which will not be described here.

[0354] S1405, in the case of determining to send the context of the first UE to the fourth access network device and the first UE being legal, the third access network device sends the context of the first UE to the fourth access network device.

[0355] In this method, since the multiple RNAs of the fourth access network device include the RNA corresponding to the fourth access network device, and the RNA of the first UE is at the cell level, the third access network device cannot determine whether the RNA of the first UE is located in the multiple RNAs of the target cell, and thus cannot determine whether to send the context of the first UE. When the second information contains the RNA identifier of the target cell or the type of the RNAU initiated by the first UE, the first terminal device can determine whether to send the context of the first UE based on the second information, thereby facilitating the third access network device to accurately send the context of the first UE.

[0356] In this method, after the fourth access network device receives the context of the first UE, the fourth access network device can also release the first UE to the inactive state.

[0357] Since the first UE currently has no actual traffic, after releasing the first UE to the inactive state, the resources and power consumption of the first UE can be saved.

[0358] Optionally, in some embodiments, when the type of the RNAU initiated by the first UE is a periodic RNAU, the period of the RNAU initiated by the first UE can be preconfigured, and the period of the RNAU initiated by the first UE can be less than or equal to a first time interval, which can be a time interval between a time when the third access network device receives the context of the first UE and a time when the third access network device disconnects the interface connection with any one of the set of first access network devices. In this way, the problem that the fourth access network device cannot obtain the context of the first UE from the third access network device after the third access network device moves to a relatively far distance can be avoided.

[0359] In the method, after the third access network device sends the paging message to the first terminal device, the first terminal device can first return to the connected state, and then the context of the first terminal device is transferred by the third access network device, or before the third access network device moves to a farther distance, the access network device (i.e., the fourth access network device) accessed by the first terminal device can obtain the context of the first UE from the third access network device. The problem that the first terminal device cannot return to the connected state is avoided when the third access network device cannot continue to push the context of the first terminal device after the first access network device is disconnected from the access network device within the wireless network notification area range of the first terminal device.

[0360] Optionally, in some possible implementation manners, whether the RNAU initiated by the first UE is a periodic RNAU or a non-periodic RNAU, the third access network device determines to send the context of the first UE to the fourth access network device after receiving the second information. For example, in the case that the third access network device is an access network device in the NTN (such as a satellite base station), whether the RNAU initiated by the first UE is a periodic RNAU or a non-periodic RNAU, the third access network device determines to send the context of the first UE to the fourth access network device after receiving the second information, and for ordinary access network devices in the ground network, whether to send the context of the first UE can be determined based on the RNAU type of the first UE.

[0361] Optionally, the implementation manner can exist independently, that is, it can not depend on any step described in the foregoing embodiments of the present application. Through the implementation manner, when there is an opportunity to transfer the UE context in the NTN, the UE context should be transferred as much as possible to avoid the case that the UE context cannot be transferred after the Xn interface is disconnected due to the large-scale movement of the satellite base station. Optionally, in some scenarios, the first access network device can not push the context of the first UE to the third access network device.

[0362] For example, when the first access network device is disconnected from any access network device in the first access network device set, the first UE can access the fourth access network device, and then the fourth access network device can request the context of the first UE from the first access network device. In this case, the method in which the fourth access network device obtains the context of the first UE from the first access network device can refer to the method in which the fourth access network device obtains the context of the first UE from the third access network device in FIG. 14, which will not be described herein again.

[0363] Optionally, the technical solutions of the present application can also be applied to other communication system architectures, such as the O-RAN architecture. In the O-RAN architecture, when the access network devices transmit their respective RNA identifiers, or when the access network devices transmit the identifiers of the access network devices connected to their respective interfaces, the transmission can be performed through the RIC in the O-RAN architecture.

[0364] As an example, assuming that the O-RAN architecture includes a first base station and a second base station, the method in which the first base station transmits the RNA identifier of the first base station to the second base station can be as shown in FIG. 15.

[0365] S1501, the first base station sends first indication information to the RIC, and the first indication information includes the RNA identifier of the first base station. Correspondingly, the RIC receives the first indication information.

[0366] In this method, the first base station can include a first base station-CU and a first base station-DU.

[0367] In this method, the RNA identifier of the first base station is used to indicate the RNA of the first base station. Optionally, the RNA identifier of the first base station can include one or more.

[0368] When the RNA identifier of the first base station includes multiple, the RNA indicated by the RNA identifier of the first base station can include the RNA corresponding to the first base station, or can include the RNA corresponding to each serving cell of the first base station.

[0369] Optionally, when the RNA indicated by the RNA identifier of the first base station includes the RNA corresponding to the first base station, the first base station can send the first indication information to the RIC through the first base station-CU.

[0370] Optionally, when the RNA indicated by the RNA identifier of the first base station includes the RNA corresponding to each serving cell of the first base station, the first base station can send the first indication information to the RIC through the first base station-CU or the first base station-DU.

[0371] S1502, the RIC sends the first indication information to the second base station. Correspondingly, the second base station receives the first indication information.

[0372] In this method, the second base station can include a second base station-CU and a second base station-DU.

[0373] Optionally, when the RNA indicated by the RNA identifier of the first base station includes the RNA corresponding to the first base station, the RIC can send the first indication information to the second base station-CU.

[0374] Optionally, when the RNA indicated by the RNA identifier of the first base station comprises an RNA corresponding to each serving cell of the first base station, the RIC can send the first indication information to the second base station-CU or the second base station-DU.

[0375] As an example, assuming that the O-RAN architecture comprises the first base station and the second base station, the method for the first base station to transmit the identifier of the base station connected with the first base station to the second base station can be as shown in FIG. 16.

[0376] S1601, the first base station sends second indication information to the RIC, and the second indication information comprises the identifier of the base station connected with the first base station. Correspondingly, the RIC receives the second indication information.

[0377] In the method, the first base station can comprise a first base station-CU and a first base station-DU.

[0378] In the method, the identifier of the base station connected with the first base station is used to indicate the base station connected with the first base station.

[0379] In the method, the first base station can send the second indication information to the RIC through the first base station-CU.

[0380] S1602, the RIC sends the second indication information to the second base station. Correspondingly, the second base station receives the second indication information.

[0381] In the method, the second base station can comprise a second base station-CU and a second base station-DU.

[0382] In the method, the RIC can send the second indication information to the second base station-CU.

[0383] FIG. 17 is a structural schematic diagram of a communication apparatus provided by an embodiment of the present application. As shown in FIG. 17, the communication apparatus 1700 can comprise a sending module 1701, a processing module 1702 and a receiving module 1703.

[0384] As an example, the communication apparatus 1700 can be used to implement the communication method of the embodiment shown in FIG. 9. In this case, the sending module 1701 can be used to perform S901.

[0385] As another example, the communication apparatus 1700 can be used to implement the communication method of the embodiment shown in FIG. 10. In this case, the sending module 1701 can be used to perform S1001 and S1005, and the receiving module 1703 can be used to perform S1004.

[0386] As a further example, the communication apparatus 1700 can be configured to implement the communication method of the embodiment shown in Fig. 11. Wherein, the sending module 1701 can be configured to perform S1101 and S1105, and the receiving module 1703 can be configured to perform S1104.

[0387] As a further example, the communication apparatus 1700 can be configured to implement the communication method of the embodiment shown in Fig. 12. Wherein, the sending module 1701 can be configured to perform S1201.

[0388] As a further example, the communication apparatus 1700 can be configured to implement the communication method of the embodiment shown in Fig. 13. Wherein, the sending module 1701 can be configured to perform S1301.

[0389] As a further example, the communication apparatus 1700 can be configured to implement the communication method of the embodiment shown in Fig. 14. Wherein, the receiving module 1703 can be configured to perform S1402, the processing module 1702 can be configured to perform S1403 and S1404, and the sending module 1701 can be configured to perform S1405.

[0390] Optionally, the communication apparatus 1700 can be applied in a first access network device.

[0391] Fig. 18 is a structure diagram of a communication apparatus provided by another embodiment of the present application. As shown in Fig. 18, the communication apparatus 1800 can include a receiving module 1801 and a sending module 1802.

[0392] As an example, the communication apparatus 1800 can be configured to implement the communication method of the embodiment shown in Fig. 12. Wherein, the receiving module 1801 can be configured to perform S1201, and the sending module 1802 can be configured to perform S1202.

[0393] As another example, the communication apparatus 1800 can be configured to implement the communication method of the embodiment shown in Fig. 13. Wherein, the receiving module 1801 can be configured to perform S1301 and S1302, and the sending module 1802 can be configured to perform S1303.

[0394] Optionally, the communication apparatus 1800 can be applied in a third access network device.

[0395] Figure 19 is a structural schematic diagram of a communication apparatus provided by another embodiment of the present application. As shown in Figure 19, the communication apparatus 1900 includes a processor 1901 and an interface circuit 1902. The processor 1901 and the interface circuit 1902 are coupled with each other. It can be understood that the interface circuit 1902 can be a transceiver or an input / output interface. Optionally, the communication apparatus 1900 can further include a memory 1903 for storing instructions executed by the processor 1901 or storing input data required by the processor 1901 for executing instructions or storing data generated by the processor 1901 after executing instructions.

[0396] As an example, the processor 1901 can be configured to implement the functions of the processing module 1702, and the interface circuit 1902 can be configured to implement the functions of the transmitting module 1701 and the receiving module 1703.

[0397] As another example, the processor 1901 can be configured to implement the functions of the processing module 1702, and the interface circuit 1902 can be configured to implement the functions of the receiving module 1801 and the transmitting module 1802.

[0398] In this example, the communication apparatus 1900 can be an access network device, or a chip or chip system applied in an access network device.

[0399] Optionally, when the communication apparatus 1900 is a chip or chip system applied in an access network device, the transmitting / receiving can correspond to signal transmitting or receiving related behaviors, which can be understood as transmitting / receiving behaviors of radio frequency signals in an analog / intermediate frequency / radio frequency domain, or can be understood as operations of starting or controlling transmitting / receiving in a digital domain, or a combination of the two. For example, when the access network device transmits or receives various signals, the processor in the access network device transmits or receives the signals by driving or controlling radio frequency circuits. Therefore, during signal transmission and reception, the processor is the decision maker or controller of the transmission and reception operations, and the radio frequency circuit is the specific executioner of the transmission and reception, and the two cooperate with the antenna to jointly implement the transmission and reception operations.

[0400] The processor can be one or more central processing units (CPUs), which can be a single core processor or a multiple core processor in the case of a single CPU. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a graphics processing unit (GPU), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor.

[0401] The radio frequency circuit can include, but is not limited to, a radio frequency chip, a radio frequency front end, a radio frequency power amplifier (PA), a low noise amplifier (LNA), a mixer, a filter, a duplexer, etc. Optionally, the radio frequency circuit can also include an antenna integrated with the radio frequency circuit.

[0402] The method steps in the embodiments of the present application can be implemented in the form of hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in a memory or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal. Of course, the processor and the storage medium can also exist as discrete components in the network device or the terminal.

[0403] In this application, the memory can include cache, random access memory (RAM), flash memory, read-only memory (ROM), synchronous dynamic random access memory (SDRAM), programmable read-only memory, erasable programmable ROM (EPROM), electrically erasable programmable ROM, register, hard disk drive (HDD), or solid-state drive (SSD), mobile hard disk, or compact disc read-only memory (CD-ROM) and the like. The memory is any medium capable of storing or carrying the desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory in the embodiments of the present application can also be a circuit or any other device capable of realizing the storage function, used for storing computer programs or instructions, and / or data.

[0404] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are performed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment or other programmable apparatus. The computer programs or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another, for example, the computer programs or instructions can be transferred from one website site, computer, server or data center to another website site, computer, server or data center through wired or wireless manner. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center and the like integrated with one or more available media. The available media can be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape; an optical medium, such as a digital video disc; and a semiconductor medium, such as a solid-state disk.

[0405] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program or instructions, and the computer program or instructions are executed by a computer (for example, a processor) to implement part or all steps of any one of the methods performed by any device in the embodiments of the present application.

[0406] The embodiment of the present application further provides a computer program product including a computer program or a set of instructions, which, when executed on a computer, implements part or all steps of any one of the methods performed by any device in the embodiments of the present application.

[0407] In various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be referred to each other if there is no special description and logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0408] It can be understood that various numbers involved in the embodiments of the present application are only distinguished for convenience of description, and are not used to limit the scope of the embodiments of the present application. The size of the serial number of the above processes does not mean the execution order, and the execution order of the processes should be determined according to their functions and inherent logic.

Claims

1. A communication method characterized by comprising: The method applied to a first access network device comprises: In a case where it is determined that an interface connection with a second access network device is to be disconnected, sending a paging message or sending a context of a first terminal device to a core network device, the paging message being used to page the first terminal device, a radio network notification area of the second access network device comprising a radio network notification area of the first terminal device.

2. The method of claim 1, wherein, The second access network device is included in a first access network device set, a radio network notification area of each access network device in the first access network device set comprising a radio network notification area of the first terminal device; The sending of the paging message comprises: distributing the paging message to each access network device in the first access network device set respectively; or sending the paging message to the second access network device.

3. The method according to claim 1 or 2, characterized in that, The method further comprises: receiving first information, the first information comprising radio network notification area identifiers of each access network device in the first access network device set, the radio network notification area identifiers of each access network device comprising a plurality, the plurality of radio network notification area identifiers corresponding to a plurality of radio network notification areas one by one; the plurality of radio network notification areas comprising a radio network notification area corresponding to each access network device or a radio network notification area corresponding to each serving cell of each access network device.

4. A communication method characterized by comprising: The method applied to a third access network device comprises: In a case where a first access network device and a second access network device are to disconnect an interface connection or the first access network device and the second access network device have disconnected an interface connection, receiving a context of a first terminal device sent by the first access network device, a radio network notification area of the second access network device comprising a radio network notification area of the first terminal device; sending a paging message or receiving second information, the paging message being used to page the first terminal device, the second information being used to request a context of the first terminal device; sending the context of the first terminal device.

5. The method of claim 4, wherein, The second access network device is included in a first access network device set, a radio network notification area of each access network device in the first access network device set comprising a radio network notification area of the first terminal device; The third access network device belongs to the first access network device set, the third access network device having an interface connection with any one access network device in the first access network device set except the third access network device; or, the third access network device does not belong to the first access network device set, the third access network device having an interface connection with any one access network device in the first access network device set.

6. The method according to claim 4 or 5, characterized in that, The context of the first terminal device comprises one or more of the following information: a cell identifier under an access network device in the first access network device set and a truncated message authentication code corresponding to the cell under the access network device in the first access network device set, security context information corresponding to the access network device in the first access network device set, identification information of the first terminal device, or information used to indicate a radio network notification area of the first terminal device.

7. The method according to any one of claims 4 to 6, characterized in that, The second information includes a radio network notification area identifier of a target cell or a type of radio network notification area update initiated by the first terminal device, the target cell being a cell accessed by the first terminal device, and the type of radio network notification area update initiated by the first terminal device including a periodic radio network notification area update or an aperiodic radio network notification area update.

8. A communication device, characterized by comprising functional modules for implementing the method of any one of claims 1 to 3, or comprising functional modules for implementing the method of any one of claims 4 to 7.

9. A communication device, characterized by comprising: a memory and a processor; the memory being configured to store program instructions; the processor being configured to cause the apparatus to perform the method of any one of claims 1 to 3, or to cause the apparatus to perform the method of any one of claims 4 to 7, by executing the computer program or instructions stored in the memory and / or by logic circuitry.

10. A computer readable storage medium characterized by, the computer readable storage medium stores computer executable instructions that, when executed on a communications apparatus, cause the method of any one of claims 1 to 3 to be implemented, or cause the method of any one of claims 4 to 7 to be implemented.

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