Non-terrestrial network communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. In the method, a terminal device acquires a first identifier used for identifying a first context of the terminal device related to a first network device; when the terminal device has an access layer security context related to the first network device, the first identifier and a first token are sent to a second network device; the terminal device is verified by means of the first token, a first target cell corresponds to the first token, and at least one cell includes the first target cell managed by the second network device, so that the terminal device can access the first target cell. Thus, when the first network device leaves an area covering the terminal device, the second network device covering the terminal device can verify the terminal device on the basis of the first identifier, so that the access efficiency can be improved, and the access time delay can be reduced.

Description

A non-terrestrial network communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on April 3, 2024, with application number 202410408843.9 and invention name “A method and communication device for non-terrestrial network communication”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and more specifically, to a method and a communication device for non-terrestrial network communications. Background Art

[0003] Traditional terrestrial networks (TNs) cannot provide seamless coverage for terminal devices, especially in locations where base stations cannot be deployed, such as in the ocean, deserts, and in the air. The introduction of non-terrestrial networks (NTNs), by deploying base stations or some base station functions on non-terrestrial network devices such as satellites, can provide seamless coverage for terminal devices and improve communication reliability.

[0004] When a terminal accesses a satellite and the core network, simultaneous connectivity between the satellite and the terminal and between the satellite and the core network is required. However, due to satellite mobility, there may be situations where both connections are not available simultaneously. Ensuring secure access to the network, such as authenticating the terminal, is crucial to efficient communication. Summary of the Invention

[0005] The present application provides a method for non-terrestrial network communication, which can quickly achieve access to terminal devices through a first identifier and improve communication efficiency.

[0006] In a first aspect, a method for non-terrestrial network communication is provided. The method can be executed by a terminal device or a component of the terminal device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the terminal device as an example.

[0007] The method includes: obtaining a first identifier, the first identifier is used to identify a first context of a terminal device related to a first network device, the first context includes at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, a next hop chaining count (NCC) corresponding to at least one cell, and an unused NCC; when the terminal device has an access layer security context related to the first network device, sending the first identifier and the first token to a second network device, the first token is used to verify the terminal device, the first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by the second network device; and accessing the first target cell.

[0008] Based on the above scheme, the first identifier can be used to identify the first context of the terminal device related to the first network device. When the first network device stops serving the area of ​​the terminal device and the second network device serves the area of ​​the terminal device, the second network device can verify the terminal device based on the first identifier and re-establish the RRC connection, so that the terminal device can access the first target cell managed by the second network device. This can improve access efficiency, reduce access delay, and thus improve communication efficiency.

[0009] As an implementation manner, obtaining the first identifier includes: receiving the first identifier from a first network device.

[0010] Exemplarily, the first identifier is carried in at least one of the following messages: an access stratum security mode command (AS SMC) message, a radio resource control (RRC) connection establishment (RRCConnectionSetup) message.

[0011] As another implementation method, obtaining the first identifier includes: determining the first identifier based on at least one of a cell identity of the first cell, a physical cell identifier (PCI) of the first cell, and a cell radio network temporary identifier (C-RNTI) allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

[0012] Based on the above scheme, the first network device can indicate the first identifier to the terminal device through an AS SMC message or an RRC connection establishment message, or the terminal device can determine the first identifier based on the information of its service cell, so that the second network device can complete the verification of the terminal device based on the first identifier to ensure communication security.

[0013] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0014] In combination with the first aspect, in one implementation, the method also includes: receiving auxiliary information corresponding to at least one network device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context, and at least one network device includes a second network device; determining that the second network device is about to cover the terminal device based on the auxiliary information, and initiating cell selection.

[0015] Based on the above solution, the first network device sends auxiliary information corresponding to at least one network device to the terminal device, so that the terminal device determines that the second network device is about to cover the terminal device to start cell selection, so that it can select the cell managed by the second network device, so that the access process continues, ensuring the continuity of access and avoiding power consumption caused by invalid and excessive cell selection of the terminal device.

[0016] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0017] In combination with the first aspect, in one implementation, after sending the first token to the second network device, the method further includes: receiving a second identifier from the second network device, where the second identifier is used to identify a second context of a terminal device related to the second network device.

[0018] Based on the above solution, the second network device sends the second identifier to the terminal device, so that the terminal device can update the identifier used to identify the context, ensuring that subsequent communications proceed normally.

[0019] Exemplarily, the second identifier is carried in at least one of the following messages: an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reestablishment message.

[0020] Optionally, the second identifier includes fourth information and / or fifth information, the fourth information is used to identify the second network device, and the fifth information is used to identify the context of the terminal device related to the second network device.

[0021] In a second aspect, a method for non-terrestrial network communication is provided. The method can be performed by a second network device or a component of the second network device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the second network device as an example.

[0022] The method includes: receiving a first identifier and a first token from a terminal device, the first identifier is used to identify a first context of the terminal device related to a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, an unused NCC, a first target cell corresponding to the first token, and at least one cell including the first target cell managed by a second network device; determining a second token based on the first context corresponding to the first identifier; and verifying the terminal device based on the first token and the second token.

[0023] As an implementation method, the method also includes: receiving a first context and a first identifier from a first network device, the first context including a second token; wherein, determining the second token based on the first context corresponding to the first identifier includes: identifying or retrieving the first context based on the first identifier, and obtaining the second token from the first context.

[0024] As another implementation manner, the method also includes: receiving a first context and a first identifier from a first network device, the first context including a first key and a first security algorithm, the first key being a key used by the first cell, and the first security algorithm being a security algorithm used by the first cell; wherein, determining the second token based on the first context corresponding to the first identifier includes: identifying the first context based on the first identifier, obtaining the first key from the first context; and generating the second token based on the first key and the first security algorithm.

[0025] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0026] In combination with the second aspect, in one implementation, the method further includes: determining a second identifier, the second identifier being used to identify a second context of a terminal device related to the second network device, and the second context being used to update the first context.

[0027] In combination with the second aspect, in one implementation, the method further includes: sending first information and a second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0028] Based on the above solution, the second network device can indicate the second context and the correspondence between the first identifier and the second identifier to the core network, so that the core network can update the terminal device context and the corresponding identifier to ensure that subsequent communications proceed normally.

[0029] In combination with the second aspect, in one implementation, the method further includes: sending a second identifier to the terminal device.

[0030] Exemplarily, the second identifier is carried in at least one of the following messages: an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reestablishment message.

[0031] Optionally, the second identifier includes fourth information and / or fifth information, the fourth information is used to identify the second network device, and the fifth information is used to identify the context of the terminal device related to the second network device.

[0032] In a third aspect, a method for non-terrestrial network communication is provided. The method can be performed by a first network device or a component of the first network device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the first network device as an example.

[0033] The method includes: determining a first identifier, the first identifier is used to identify a first context of a terminal device related to a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC; sending the first identifier to the terminal device and the second network device.

[0034] Exemplarily, sending the first identifier to the terminal device includes: carrying the first identifier through at least one of an AS SMC message and an RRC connection establishment message.

[0035] Exemplarily, sending the first identifier to the second network device includes: sending the first identifier to the second network device through non-terminal device related signaling.

[0036] In combination with the third aspect, in one implementation, the method further includes: sending auxiliary information corresponding to at least one network device to the terminal device, at least one network device supports a store and forward function, and / or at least one network device has a first context.

[0037] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0038] In combination with the third aspect, in one implementation, the method further includes: sending the first context and the first identifier to the second network device and / or the core network.

[0039] Based on the above solution, the first network device can send the first context and the first identifier to the second network device, so that the second network device can determine the second token for verifying the terminal device according to the first identifier, thereby ensuring communication security.

[0040] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0041] It should be understood that the beneficial effects of the second to third aspects and any implementation thereof can refer to the first aspect and any implementation thereof.

[0042] In a fourth aspect, a method for non-terrestrial network communication is provided. This method can be executed by a terminal device or by a component of the terminal device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the terminal device as an example.

[0043] The method includes: obtaining a first identifier, the first identifier being used to identify a first context of a terminal device associated with a first network device; receiving a paging message or a physical downlink control channel (PDCCH) command from a second network device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier; determining a paging timing based on the first identifier to monitor the paging message; or decoding the PDCCH command based on the first identifier.

[0044] Based on the above scheme, the first identifier can be used to identify the first context of the terminal device related to the first network device. When the first network device stops serving the area of ​​the terminal device and the second network device serves the area of ​​the terminal device, the second network device can wake up the terminal device for access based on the first identifier, for example, waking up the terminal device to initiate random access and establish an RRC connection. This can improve access efficiency, reduce access delay, and thus improve communication efficiency.

[0045] Exemplarily, the terminal device does not establish an access layer security context related to the first network device.

[0046] As an implementation manner, obtaining the first identifier includes: receiving the first identifier from a first network device.

[0047] Exemplarily, the first identifier is carried in an RRC connection establishment message.

[0048] Based on the above scheme, the first network device indicates the first identifier to the terminal device through the RRC connection establishment message. The terminal device can answer the paging message or decode the PDCCH command based on the first identifier, so that random access can be initiated based on the triggering of the paging message or PDCCH command to ensure that the access process proceeds normally.

[0049] As another implementation method, obtaining the first identifier includes: determining the first identifier based on at least one of the cell identifier of the first cell, the PCI of the first cell, and the C-RNTI allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

[0050] Based on the above scheme, the terminal device determines the first identifier by itself according to the relevant information of the first cell. It can receive the paging message or decode the PDCCH command based on the first identifier, and thus initiate random access based on the triggering of the paging message or PDCCH command to ensure that the access process proceeds normally.

[0051] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0052] In combination with the fourth aspect, in one implementation, the method also includes: receiving auxiliary information corresponding to at least one network device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context, and at least one network device includes a second network device; determining that the second network device is about to cover the terminal device based on the auxiliary information, and initiating cell selection.

[0053] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0054] In combination with the fourth aspect, in one implementation, the method further includes: receiving a second identifier from a second network device, where the second identifier is used to identify a second context of a terminal device related to the second network device.

[0055] Based on the above solution, the second network device sends the second identifier to the terminal device, so that the terminal device can update the identifier used to identify the context, ensuring that subsequent communications proceed normally.

[0056] Exemplarily, the second identifier is carried in at least one of the following messages: AS SMC message, RRC connection establishment message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

[0057] Optionally, the second identifier includes fourth information and / or fifth information, the fourth information is used to identify the second network device, and the fifth information is used to identify the context of the terminal device related to the second network device.

[0058] In a fifth aspect, a method for non-terrestrial network communication is provided. The method can be performed by a second network device or a component of the second network device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the second network device as an example.

[0059] The method includes: receiving a first identifier from a first network device, the first identifier being used to identify a first context of a terminal device related to the first network device; when a second network device covers the terminal device, sending a paging message or a PDCCH command to the terminal device, wherein the paging message includes the first identifier, or the PDCCH command is encrypted by the first identifier.

[0060] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0061] In combination with the fifth aspect, in one implementation, the method further includes: determining a second identifier, the second identifier being used to identify a second context of a terminal device related to the second network device, and the second context being used to update the first context.

[0062] In combination with the fifth aspect, in one implementation, the method further includes: sending first information and a second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0063] Based on the above solution, the second network device can indicate the second context and the correspondence between the first identifier and the second identifier to the core network, so that the core network can update the terminal device context and the corresponding identifier to ensure that subsequent communications proceed normally.

[0064] In combination with the fifth aspect, in one implementation, the method further includes: sending a second identifier to the terminal device.

[0065] Exemplarily, the second identifier is carried in at least one of the following messages: AS SMC message, RRC connection establishment message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

[0066] Optionally, the second identifier includes fourth information and / or fifth information, the fourth information is used to identify the second network device, and the fifth information is used to identify the context of the terminal device related to the second network device.

[0067] In a sixth aspect, a method for non-terrestrial network communication is provided. The method can be performed by a first network device or by a component of the first network device (e.g., a chip, circuit, or chip system). For ease of understanding, the following description uses the first network device as an example.

[0068] The method includes: determining a first identifier, where the first identifier is used to identify a first context of a terminal device related to a first network device; and sending the first identifier to the terminal device and a second network device.

[0069] Exemplarily, sending the first identifier to the terminal device includes: carrying the first identifier through an RRC connection establishment message.

[0070] Exemplarily, sending the first identifier and / or the first context to the second network device includes: sending the first identifier and / or the first context to the second network device through non-terminal device related signaling.

[0071] The first identifier may be included in the first context or exist independently of the first context.

[0072] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0073] In combination with the sixth aspect, in one implementation, the method further includes: sending auxiliary information corresponding to at least one network device to the terminal device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context.

[0074] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0075] In combination with the sixth aspect, in one implementation, the method further includes: sending the first context and the first identifier to the second network device and / or the core network.

[0076] In a seventh aspect, a non-terrestrial network communication device is provided, which may be a terminal device or a component of a terminal device (such as a chip or a circuit or a chip system).

[0077] The device includes: a processing unit, used to obtain a first identifier, the first identifier is used to identify a first context of a terminal device related to a first network device, the first context includes at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC; a transceiver unit, used to send the first identifier and the first token to a second network device when the terminal device has an access layer security context related to the first network device, the first token is used to verify the terminal device, the first target cell corresponds to the first token, and at least one cell includes the first target cell managed by the second network device; the processing unit is also used to: access the first target cell.

[0078] As an implementation manner, the processing unit is specifically configured to: receive a first identifier from a first network device.

[0079] Exemplarily, the first identifier is carried in at least one of the following messages: an access layer AS SMC message, and an RRC connection establishment message.

[0080] As another implementation method, the processing unit is specifically used to: determine the first identifier based on at least one of the cell identifier of the first cell, the physical cell identifier of the first cell, and the cell wireless network temporary identifier allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

[0081] In combination with the seventh aspect, in one implementation, the transceiver unit is also used to: receive auxiliary information corresponding to at least one network device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context, and at least one network device includes a second network device; the processing unit is also used to: determine that the second network device is about to cover the terminal device based on the auxiliary information, and start cell selection.

[0082] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0083] In combination with the seventh aspect, in one implementation, the transceiver unit is further used to: receive a second identifier from the second network device, where the second identifier is used to identify a second context of the terminal device related to the second network device.

[0084] Exemplarily, the second identifier is carried in at least one of the following messages: an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reestablishment message.

[0085] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0086] In an eighth aspect, a device for non-terrestrial network communication is provided. The device may be a second network device or a component of the second network device (such as a chip or a circuit or a chip system).

[0087] The device includes: a transceiver unit, used to receive a first identifier and a first token from a terminal device, the first identifier is used to identify a first context of the terminal device related to a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, an unused NCC, a first target cell corresponding to the first token, and at least one cell including the first target cell managed by a second network device; a processing unit, used to: determine a second token based on the first context corresponding to the first identifier; and verify the terminal device based on the first token and the second token.

[0088] As an implementation manner, the processing unit is further configured to: receive a first context and a first identifier from a first network device, the first context including a second token; and the processing unit is specifically configured to: retrieve the second token from the first context according to the first identifier.

[0089] As another implementation method, the processing unit is also used to: receive a first context and a first identifier from a first network device, the first context including a first key and a first security algorithm, the first key is a key used by the first cell, and the first security algorithm is a security algorithm used by the first cell; wherein the processing unit is specifically used to: identify the first context according to the first identifier, obtain the first key from the first context; and generate a second token according to the first key and the first security algorithm.

[0090] In combination with the eighth aspect, in one implementation, the processing unit is further used to: determine a second identifier, the second identifier is used to identify a second context of the terminal device related to the second network device, and the second context is used to update the first context.

[0091] In combination with the eighth aspect, in one implementation, the transceiver unit is further used to: send first information and a second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0092] Based on the above solution, the second network device can indicate the second context and the correspondence between the first identifier and the second identifier to the core network, so that the core network can update the terminal device context and the corresponding identifier to ensure that subsequent communications proceed normally.

[0093] In combination with the eighth aspect, in one implementation, the transceiver unit is further used to: send a second identifier to the terminal device.

[0094] Exemplarily, the second identifier is carried in at least one of the following messages: an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reestablishment message.

[0095] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0096] In a ninth aspect, a non-terrestrial network communication device is provided. The device may be a first network device or a component of the first network device (eg, a chip or a circuit or a chip system).

[0097] The device includes: a processing unit, used to determine a first identifier, the first identifier is used to identify a first context of a terminal device related to a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC; a transceiver unit, used to send the first identifier to the terminal device and the second network device.

[0098] Exemplarily, the transceiver unit is specifically configured to carry the first identifier through at least one of an AS SMC message and an RRC connection establishment message.

[0099] Exemplarily, the transceiver unit is specifically configured to send the first identifier to the second network device via non-terminal device related signaling.

[0100] In combination with the ninth aspect, in one implementation, the transceiver unit is also used to: send auxiliary information corresponding to at least one network device to the terminal device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context.

[0101] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0102] In combination with the ninth aspect, in one implementation, the transceiver unit is further used to: send the first context and the first identifier to the second network device and / or the core network.

[0103] Optionally, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device.

[0104] It should be understood that the beneficial effects of the eighth to ninth aspects and any of their implementations can refer to the seventh aspect and any of its implementations.

[0105] In a tenth aspect, a device for non-terrestrial network communication is provided. The device may be a terminal device or a component of a terminal device (such as a chip or a circuit or a chip system).

[0106] The device includes: a processing unit, used to obtain a first identifier, the first identifier is used to identify a first context of a terminal device related to a first network device; receive a paging message or a PDCCH command from a second network device, wherein the paging message includes the first identifier, or the PDCCH command is encrypted by the first identifier; the processing unit is also used to: determine a paging timing to answer the paging message based on the first identifier; or decode the PDCCH command based on the first identifier.

[0107] Exemplarily, the terminal device does not establish an access layer security context related to the first network device.

[0108] As an implementation manner, the processing unit is specifically configured to: receive a first identifier from a first network device.

[0109] Exemplarily, the first identifier is carried in an RRC connection establishment message.

[0110] As another implementation method, the processing unit is specifically used to: determine the first identifier based on at least one of the cell identifier of the first cell, the PCI of the first cell and the C-RNTI allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

[0111] In combination with the tenth aspect, in one implementation, the device also includes: a transceiver unit for receiving auxiliary information corresponding to at least one network device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context, and at least one network device includes a second network device; the processing unit is used to: determine that the second network device is about to cover the terminal device based on the auxiliary information; and start cell selection.

[0112] Exemplarily, the auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0113] In combination with the tenth aspect, in one implementation, the transceiver unit is further used to: receive a second identifier from the second network device, where the second identifier is used to identify a second context of the terminal device related to the second network device.

[0114] Exemplarily, the second identifier is carried in at least one of the following messages: AS SMC message, RRC connection establishment message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

[0115] In the eleventh aspect, a device for non-terrestrial network communication is provided. The device can be a second network device or a component of the second network device (such as a chip or circuit or chip system).

[0116] The device includes: a transceiver unit for receiving a first identifier from a first network device, the first identifier being used to identify a first context of a terminal device related to the first network device; the transceiver unit is also used to: when the second network device covers the terminal device, send a paging message or a PDCCH command to the terminal device, wherein the paging message includes the first identifier, or the PDCCH command is encrypted by the first identifier.

[0117] In combination with the eleventh aspect, in one implementation, the apparatus further includes: a processing unit, configured to determine a second identifier, the second identifier being used to identify a second context of a terminal device associated with the second network device, the second context being used to update the first context.

[0118] In combination with the eleventh aspect, in one implementation, the transceiver unit is further used to: send first information and a second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0119] In combination with the eleventh aspect, in one implementation, the transceiver unit is further used to: send a second identifier to the terminal device.

[0120] Exemplarily, the second identifier is carried in at least one of the following messages: AS SMC message, RRC connection establishment message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

[0121] In the twelfth aspect, a device for non-terrestrial network communication is provided. The device can be a first network device or a component of the first network device (such as a chip or circuit or chip system).

[0122] The device includes: a processing unit, used for determining a first identifier, where the first identifier is used for identifying a first context of a terminal device related to a first network device; and a transceiver unit, used for sending the first identifier to the terminal device and a second network device.

[0123] Exemplarily, the transceiver unit is specifically configured to carry the first identifier via an RRC connection establishment message.

[0124] Exemplarily, the transceiver unit is specifically configured to send the first identifier to the second network device via non-terminal device related signaling.

[0125] In combination with the twelfth aspect, in one implementation, the transceiver unit is also used to: send auxiliary information corresponding to at least one network device to the terminal device, at least one network device supports storage and forwarding functions, and / or at least one network device has a first context.

[0126] In combination with the twelfth aspect, in one implementation, the transceiver unit is further used to: send the first context and the first identifier to the second network device and / or the core network.

[0127] In a thirteenth aspect, the present application provides a communication device comprising an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory is used to store the necessary computer programs or instructions for implementing the functions involved in the first to seventh aspects above. The one or more processors can execute the computer program or instructions. When the computer program or instructions are executed, the communication device implements the method in any possible design or implementation of the first to seventh aspects above. The interface circuit is used to implement the communication function within the communication device and / or the communication function of the communication device with other devices or components.

[0128] In one possible design, the processor is configured to communicate with other devices or components through the interface circuit.

[0129] In one possible design, the communication device may also include the memory.

[0130] In a fourteenth aspect, the present application provides a processor for executing the methods provided in the above aspects.

[0131] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as processor output, reception, input and other operations, and can also be understood as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0132] In a fifteenth aspect, the present application provides a computer-readable storage medium, which stores program code for execution by a device, and the program code includes a method for executing any of the above aspects or its implementation method.

[0133] In a sixteenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method provided by any one of the above aspects or its implementation.

[0134] In the seventeenth aspect, the present application provides a chip, which includes a processor and a communication interface. The processor reads instructions stored in the memory through the communication interface and executes the method provided by any one of the above aspects or its implementation method.

[0135] Optionally, the processor may be a processing circuit or a logic circuit, and the communication interface may be an input or output interface, wherein the processing circuit or logic circuit is used for information processing, and the input or output interface is used for sending and receiving information or data.

[0136] Optionally, as an implementation method, the chip also includes a memory, in which a computer program or instruction is stored, and the processor is used to execute the computer program or instruction stored in the memory. When the computer program or instruction is executed, the processor is used to execute the method provided by any of the above aspects or its implementation methods.

[0137] It should be understood that the beneficial effects of the seventh to seventeenth aspects and any implementation thereof can be referred to the first to sixth aspects and any implementation thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0138] FIG1 is a schematic diagram of a network architecture applicable to an embodiment of the present application.

[0139] FIG2 is a schematic diagram of the functions implemented by a centralized unit (CU) and a distributed unit (DU).

[0140] FIG3 is another schematic diagram of a network framework applicable to a communication system according to an embodiment of the present application.

[0141] Figure 4 is a schematic diagram of several architectures of satellite communications.

[0142] 5 and 6 are schematic flow charts of the non-terrestrial network communication method provided by the present application.

[0143] FIG7 is a schematic diagram of a paging process.

[0144] FIG8 is a schematic diagram of random access triggered by a PDCCH command.

[0145] 9 and 10 are schematic flow charts of the non-terrestrial network communication method provided by the present application.

[0146] 11 and 12 are schematic structural diagrams of communication devices provided in embodiments of the present application. DETAILED DESCRIPTION

[0147] The technical solution in this application will be described below with reference to the accompanying drawings.

[0148] The technical solution of the present application can be applied to non-terrestrial network (NTN) systems such as satellite communication systems and high altitude platform station (HAPS) communications, for example, integrated communication and navigation (ICaN) systems, global navigation satellite systems (GNSS), etc.

[0149] Satellite communication systems can be integrated with traditional mobile communication systems. For example, the traditional mobile communication systems may be fourth-generation (4G) communication systems, fifth-generation (5G) communication systems, new radio (NR) systems, future mobile communication systems, Internet of Things (IoT) networks, or vehicle-to-everything (V2X) networks.

[0150] The above-mentioned communication system applicable to the present application is only an example, and the communication system applicable to the present application is not limited to this. It is described uniformly here and will not be repeated below.

[0151] It should be understood that since traditional terrestrial networks (TN) cannot provide seamless coverage for terminal devices, especially in places where base stations cannot be deployed, such as the sea, desert, and air, after the introduction of NTN, by deploying base stations or part of the base station functions on high-altitude platforms or NTN devices such as satellites, seamless coverage can be provided for terminal devices, thereby improving system reliability.

[0152] Figure 1 is a schematic diagram of a network architecture applicable to an embodiment of the present application. Taking a 5G network as an example, a ground mobile terminal device accesses the network through a 5G new air interface. The 5G access network equipment is deployed on a satellite and connected to the core network (CN) on the ground through a wireless link. At the same time, there is an inter-satellite link (ISL) between satellites to complete the signaling interaction and user data transmission between access network devices. The various network elements in Figure 1 and their interfaces are described as follows:

[0153] Terminal device: A mobile device that supports the 5G new air interface, typically a mobile phone, tablet, or other mobile device. It can access the satellite network through the air interface and initiate calls, access the Internet, and perform other services.

[0154] 5G access network equipment: mainly provides wireless access services, dispatches wireless resources to access terminals, and provides reliable wireless transmission protocols and data encryption protocols, such as base stations.

[0155] 5G core network: used to implement functions such as user access control, mobility management, session management, user security authentication, and billing management. For these functions, the 5G core network implements them through corresponding functional units, and these functional units can be divided into control plane functional entities and user plane functional entities. For example, the access and mobility management function (AMF) network element is responsible for user intervention management, security authentication, mobility management and other functions belonging to the control plane. The session management function (SMF) network element is used to support customized mobility management solutions together with the AMF network element. The user plane function (UPF) network element is responsible for managing user plane data transmission, traffic statistics and other functions. Among them, functional network elements can also be called functional entities or network elements.

[0156] Ground station: responsible for forwarding signaling and service data between 5G access network equipment and 5G core network.

[0157] 5G New Air Interface: The wireless link between the terminal and access network equipment.

[0158] Xn interface: The interface between 5G access network devices, mainly used for signaling interaction such as switching.

[0159] NG interface: The interface between 5G access network equipment and 5G core network, mainly used for signaling such as the non-access stratum (NAS) of the core network and user service data.

[0160] It should be understood that the terminal devices mentioned in the embodiments of the present application include various handheld devices, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem with wireless communication functions, and may specifically refer to user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device may also be a satellite phone, a cellular phone, a smart phone, a wireless data card, a wireless modem, a machine type communication device, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a terminal device in a 5G network or a future communication network, etc.

[0161] The satellite mentioned in the embodiments of the present application may also be a satellite base station, or a network-side device carried on a satellite. The satellite in the present application may also be a centralized unit (CU), a distributed unit (DU) or a radio unit (RU), or an open radio access network (O-RAN) node carried on a satellite. The CU and DU may be two independent satellite nodes, or they may be integrated into the same satellite node, for example, integrated into a baseband unit (BBU). The RU may be included in a radio frequency device, for example, in a remote radio unit (RRU) or an active antenna unit (AAU). The CU can be further divided into two types of nodes: the CU-control plane (CU-CP) and the CU-user plane (CU-UP).

[0162] FIG2 is a schematic diagram of the functions implemented by the CU and DU.

[0163] As shown in Figure 2(a), the CU can implement the functions of the radio resource control (RRC), packet data convergence protocol (PDCP), and service data adaptation protocol (SDAP) layers in the 3GPP standard. The DU can implement the functions of the radio link control (RLC) and medium access control (MAC) layers in the 3GPP standard, and can also complete some or all of the physical layer (PHY) functions. For detailed descriptions of the above-mentioned protocol layers, please refer to the relevant technical specifications of 3GPP. The RU can be used to implement the transmission and reception functions of radio frequency signals.

[0164] As shown in Figure 2(b), when the CU is divided into the CU-CP and the CU-UP, the CU-CP implements the functions of the RRC layer and the control plane (PDCP-C) functions of the PDCP layer. The CU-UP implements the functions of the SDAP layer and the user plane (PDCP-U) functions of the PDCP layer.

[0165] In Figure 2, E1 is the interface between CU-CP and CU-UP, F1 is the interface between CU and DU, F1-C is the interface between CU-CP and DU, and F1-U is the interface between CU-UP and DU.

[0166] In different systems, CU (or CU-CP and CU-UP), DU, or RU may also have different names. For example, in the O-RAN system, CU may also be called open CU (open CU, O-CU), DU may also be called open DU (open DU, O-DU), and RU may be called open RU (open RU, O-RU). CU-CP may also be called open CU-CP (open CU-CP, O-CU-CP), and CU-UP may also be called open CU-UP (open CU-UP, O-CU-UP). It should be understood that the O-RAN system is designed to realize an intelligent and open access network. The main feature of the O-RAN system is the separation of software and hardware, which realizes the virtualization of network functions and the standardization of hardware. In addition, the O-RAN system can also introduce artificial intelligence (AI) or machine learning (ML).

[0167] FIG3 is another schematic diagram of a network framework applicable to a communication system according to an embodiment of the present application.

[0168] As shown in Figure 3, the communication system includes a radio access network (RAN) intelligent controller (RIC). The RIC can be an AI module for implementing AI-related functions. The RIC includes near-real time RIC (near-real time RIC, near-RT RIC or nRT RIC) and non-real time RIC (non-real time RIC, non-RT RIC or NRT RIC). Among them, non-real-time RIC mainly processes non-real-time information, such as data that is not sensitive to delay, and the delay of the data can be in the order of seconds. Real-time RIC mainly processes near real-time information, such as data that is relatively sensitive to delay, and the delay of the data is in the order of tens of milliseconds.

[0169] Near-real-time RIC is used to implement near-real-time intelligent management of the RAN. Through data collection and related operations, it enables near-real-time control and optimization of O-RAN modules and resources. Near-real-time RIC can exchange information with RAN nodes (such as CU, CU-CP, CU-UP, DU, and / or RU) and / or terminals. Non-real-time RIC is used to implement non-real-time intelligent management of RAN functions. It can implement AI / ML workflows including model training and model updates, and guide applications or functions in near-real-time RIC based on policies.

[0170] The near-real-time RIC and non-real-time RIC can also be set up as separate network elements. Optionally, the near-real-time RIC and non-real-time RIC can also be part of other devices. For example, the near-real-time RIC is set up in the RAN node (e.g., CU, DU), while the non-real-time RIC is set up in the OAM, cloud server, core network equipment, or other network equipment.

[0171] It should be understood that the above network architecture is only an example, and the embodiments of the present application can also be applied to other network architectures.

[0172] As communication requirements continue to increase, traditional terrestrial networks (TNs) are unable to provide seamless coverage for terminal devices, especially in areas where base stations cannot be deployed, such as in the ocean, deserts, and in the air. The introduction of non-terrestrial networks (NTNs), by deploying base stations or some base station functions on non-terrestrial network devices such as satellites, can provide seamless coverage for terminal devices and improve communication reliability.

[0173] According to the satellite altitude, that is, the satellite orbit altitude, the satellite system can be divided into high-orbit satellites and medium- and low-orbit satellites. Among them, high-orbit satellites are also called geostationary earth orbit (GEO) satellites. Their movement speed is the same as the earth's rotation system, so the satellite remains stationary relative to the ground. Correspondingly, the cells of GEO satellites are also stationary. The coverage of GEO satellite cells is relatively large, and the general cell diameter is 500km. Medium- and low-orbit satellites include medium earth orbit (MEO) satellites and low earth orbit (LEO) satellites. Medium-orbit satellites and low-orbit satellites move faster relative to the ground, so the service coverage areas provided by medium-orbit satellites and low-orbit satellites also move accordingly. Therefore, for medium- and low-orbit satellites, the cells covered by the satellites can be divided into two types:

[0174] (1) Quasi-earth-fixed cell: A moving satellite forms a cell by adjusting its beam. The position of the formed cell on the ground remains stationary for a certain period of time.

[0175] (2) Earth-moving cell: The satellite does not dynamically adjust its beam direction. The cell covered by the satellite's beam moves as the satellite moves.

[0176] Satellites are generally classified into two categories based on their operating mode: The first type is transparent satellites, which retransmit radio frequency signals from base stations located on the ground. The second type is regenerative satellites, which have all or part of the functions of a base station. This means that a base station or a portion of its functions are deployed on the satellite. This is illustrated below with reference to Figure 4, where (a) corresponds to a transparent satellite, and (b) through (d) correspond to regenerative satellites.

[0177] Figure 4 is a schematic diagram of several satellite communication architectures. The architectures shown in (a) to (d) of Figure 4 can be collectively referred to as NTN-based NG-RAN architectures.

[0178] The architecture shown in Figure 4(a) is a transparent satellite RAN architecture. As shown in Figure 4(a), in this architecture, the satellite forwards the radio frequency signal of the base station located on the ground. The role of the satellite is to implement radio frequency filtering, frequency conversion and amplification. That is, the satellite mainly acts as a layer 1 relay (L1 relay), regenerating the physical layer signal, and does not have other higher protocol layers. Therefore, the satellite copies the NR Uu radio interface signal from the feeder link (between the NTN gateway and the satellite) to the service link (between the satellite and the UE), and vice versa. The satellite radio interface (SRI) on the feeder link transmits the NR Uu interface signal, that is, the satellite does not terminate the NR Uu interface signal, but copies the signal. The NTN gateway supports all necessary functions for forwarding the NR Uu interface signal. Different transmission satellites can be connected to the same ground base station (such as the next generation NodeB (gNB) or evolved NodeB (eNB) in the 5G system). The SRI interface is a transmission link between the NTN gateway and the satellite. In this architecture, the satellite and NTN gateway can be regarded as a remote radio unit.

[0179] The architecture shown in Figure 4(b) is a regenerative satellite without an ISL. In this architecture, the satellite acts as a base station, regenerating signals received from the ground. Specifically, the NR Uu radio interface signal is transmitted over the service link between the UE and the satellite, and the SRI signal is transmitted over the feeder link between the NTN gateway and the satellite. The NG interface signal is transmitted to the NTN gateway via the SRI interface, and then forwarded by the NTN gateway to the core network equipment on the ground. The process of transmitting the NG interface signal from the ground core network equipment to the satellite base station is similar and will not be repeated here.

[0180] The architecture shown in Figure 4(c) is a regenerative satellite with ISL architecture. In this architecture, the satellite also functions as a base station. The difference from the architecture shown in Figure 4(b) is the presence of an ISL. The ISL is an inter-satellite transmission link. As shown in Figure 4(b), a UE served by an onboard base station can access the 5G core network via the ISL. Base stations on different satellites can connect to the same terrestrial 5G core network.

[0181] The architecture shown in Figure 4(d) is the NG-RAN with a regenerative satellite based on gNB-DU architecture. In this architecture, the CU and DU of the base station are separated. The satellite is on board as the DU of the base station. The satellite regenerates the signals received from the ground, that is, the service link between the UE and the satellite transmits the NR Uu radio interface signal, and the feeder link between the NTN gateway and the satellite transmits the SRI signal. The SRI is a transmission link that can transmit the 3GPP standard logical interface F1 signal. The F1 protocol signal is transmitted on the SRI. The satellite can provide inter-satellite links (ISLs) between satellites. The NTN gateway is a transmission network layer node and supports all necessary transmission protocols. DUs on different satellites can be connected to the same ground CU.

[0182] The above RAN architecture is only for illustrative purposes. The embodiments of the present application may also be used in other NTN architectures, or 4G, 5G, and future wireless network architectures.

[0183] The architecture shown in Figure 4 (b) to (d) can be divided into two scenarios based on the coverage of NTN gateways (also called gateway stations):

[0184] Scenario 1: The NTN gateway can cover all satellites in orbit, that is, all satellites can establish an interface (S1 / NG interface) with the core network through the NTN gateway.

[0185] Scenario 2: Due to operator planning or geographical restrictions (e.g., deployment at sea), the NTN gateway cannot cover all satellites. Satellites in certain areas cannot establish feeder links with the NTN gateway, and thus cannot exchange information with the core network. Ultimately, this results in the inability to initiate NAS connections to the core network via satellite, and the satellite cannot exchange terminal signaling with the core network. In other words, terminals in this area cannot enjoy network services. In this scenario, two satellites may have an intersatellite link between them, but they cannot connect to the NTN gateway through the intersatellite link. Scenario 2 is also known as a discontinuous coverage scenario.

[0186] To address the aforementioned discontinuous coverage scenario, the standard proposes a store and forward (S&F) communication method. Specifically, for data sent by a terminal to a satellite that needs to be sent to the core network, if the satellite cannot communicate with the core network through the NTN gateway, the satellite first stores the data. When the satellite moves to an area where it can communicate with the core network through the NTN gateway, the satellite then sends the stored data to the core network. For data that the core network needs to send to a terminal via satellite, if the satellite can communicate with the core network through the NTN gateway, the core network sends the data to the satellite. The satellite then stores the data and sends the stored data to the terminal when the satellite moves to an area where it can communicate with the terminal. This scenario is referred to as discontinuous coverage.

[0187] Due to the mobility of satellites, the satellite providing services to a terminal may change during the process of connecting to the satellite and the core network. Therefore, the terminal access process in satellite communication scenarios, such as security verification, will be different from that in terrestrial communication.

[0188] To facilitate understanding, we first briefly explain the UE status and access process in terrestrial communications, such as the security verification process, including the security verification during RRC (connection) recovery and the security verification during RRC (connection) re-establishment.

[0189] 1.UE status

[0190] The RRC state of the UE includes RRC connected state and RRC idle state. There is also a special state in the RRC idle state called RRC suspended state. Specifically,

[0191] (1) When the UE is in the RRC connected state, the UE and the base station establish an RRC connection. After the access stratum (AS) security is activated, the RRC connected UE will initiate the RRC (connection) reestablishment process after detecting radio link failure, handover failure, integrity check failure, or RRC reconfiguration failure.

[0192] (2) When the UE is in the RRC idle state, no RRC connection is established between the UE and the base station.

[0193] (3) When the UE is in the RRC suspend state, the UE suspends the RRC connection, including all signaling radio bearers (SRBs) and data radio bearers (DRBs), and the UE suspends data processing, but the base station still maintains the AS context of the UE. The AS context may include one or more of the UE's current RRC configuration, current security context, C-RNTI of the source cell, cell identity of the source cell, and PCI. As an example, when the UE supports preconfigured uplink resource (PUR) data transmission or early data transmission (EDT) based on the user plane (UP), the base station may indicate a resume identity and RRC suspend in the RRC connection release message, so that the UE can leave the RRC connection state and enter the RRC suspend state. The resume identity is used to identify the suspended UE context, which is used for the UE to resume the RRC connection. When the UE resumes a suspended RRC connection, for example, when the UE needs to initiate a PUR or EDT transmission based on the user plane, or when the UE is a narrowband internet of things (NB-IoT) UE, the UE initiates an RRC (connection) resumption request.

[0194] 2. Security Verification during RRC Recovery

[0195] During RRC recovery, the UE sends an RRCConnectionResumeRequest message to the target cell (i.e., the cell selected by the UE during RRC recovery). This message includes a token (hereinafter referred to as shortMAC-I or shortResumeMAC-I). The network side verifies the UE based on the token. Specifically, the UE should set the content of the RRCConnectionResumeRequest message as follows:

[0196] (1) Indicates the recovery flag, i.e., the recovery flag indicated in the RRC connection release message;

[0197] (2) Set shortMAC-I to the 16 least significant bits of the message authentication code-integrity (MAC-I). MAC-I is determined as follows:

[0198] (a) VarShortMAC-Input is encoded using abstract syntax notation one (ASN.1), where VarShortMAC-Input includes the C-RNTI of the UE in the source cell, the PCI of the source cell, and the cell identifier of the target cell.

[0199] (b) The ASN.1 encoding result is integrity protected using the UE's Krrcint key and integrity protection algorithm in the source cell to generate a MAC-I, where all bits of the counter (count), bearer identifier (bearer), and direction (direction) required as inputs in the integrity protection algorithm are set to 1.

[0200] The UE submits the RRC Connection Resumption Request message to the underlying transport layer and sends it to the target cell. The base station corresponding to the target cell (denoted as base station 2) sends the resume identity, shortMAC-I, and cell identifier (cell ID) of the target cell in the RRC Connection Resumption Request to the base station corresponding to the source cell (denoted as base station 1). For example, base station 2 can send the above information to base station 1 in a Get UE Context Request message.

[0201] Base station 1 obtains a shortMAC-I based on the C-RNTI assigned to the UE by the source cell, the PCI of the source cell, the cell identifier of the target cell, the Krrcint key, and the integrity protection algorithm for the UE. It then compares the shortMAC-I with the shortMAC-I received from the UE by the target cell. If they are identical, verification succeeds; otherwise, verification fails. If verification succeeds, base station 1 indicates the success to base station 2, for example, by sending a Get UE Context Response message. If verification fails, base station 1 indicates the failure to base station 2, for example, by sending a Get UE Context Failure message.

[0202] 3. Security Verification in RRC Reestablishment

[0203] During the RRC reestablishment process, the UE may select a cell for reestablishment and send an RRCConnectionReestablishmentRequest message. This cell is called the new cell, and it may not be the target cell for the handover request initiated by the network. To ensure communication security, the network needs to verify the UE, or perform security authentication. This is generally done through the UE identifier and token (shortMAC-I below). The RRCConnectionReestablishmentRequest message includes the UE identifier and token, which may include the PCI and C-RNTI of the source cell.

[0204] Specifically, the UE shall set the content of the RRC connection reestablishment request message as follows, including the UE identity (including C-RNTI, PCI) and shortMAC-I:

[0205] (1) Set the c-RNTI to the C-RNTI used by the source cell (in the case of handover and mobility failure on the E-UTRA side), or the C-RNTI used by the cell that triggered the re-establishment procedure (in other cases).

[0206] (2) The PCI is set to the physical cell identity of the source cell (in the case of handover and mobility failure on the E-UTRA side), or the physical cell identity used by the cell that triggered the re-establishment process (in other cases).

[0207] (3) Set shortMAC-I to the 16 least significant bits of MAC-I. The method for determining MAC-I refers to the RRC recovery process above.

[0208] The UE submits the RRC connection reestablishment request message to the underlying transport layer and sends it to the new cell.

[0209] One approach is: the base station corresponding to the new cell (denoted as base station 3) sends the C-RNTI, PCI, shortMAC-I, and the cell identifier of the new cell in an RRC connection reestablishment request message to the base station corresponding to the source cell (denoted as base station 1). For example, base station 3 sends this information to base station 1 in a request message to obtain UE context. Base station 1 obtains a shortMAC-I based on the C-RNTI, PCI, the cell identifier of the new cell, the Krrcint key, and the integrity protection algorithm for the UE, and compares it with the shortMAC-I received from the UE by base station 3. If they are the same, the UE passes authentication. Otherwise, authentication fails.

[0210] If the verification succeeds, base station 1 indicates the verification success to base station 3, for example, by sending a Get UE Context Response message. Furthermore, base station 3 sends an RRC Connection Reestablishment message to the UE, which may include the NCC received from base station 1. If the verification fails, base station 1 indicates the verification failure to base station 3, for example, by sending a Get UE Context Failure message. Furthermore, base station 3 sends an RRC Connection Reestablishment Reject message to the UE. The RRC Connection Reestablishment Request message, RRC Connection Reestablishment message, and RRC Connection Reestablishment Reject message are not integrity protected.

[0211] Another method is RRC re-establishment due to handover failure. During handover preparation, base station 1 does not know in which cell the UE will perform RRC re-establishment. Base station 1 will send multiple cell-specific keys (such as KeNB*) and shortMAC-I to the target base station.

[0212] For X2 handover, the target base station uses KeNB* sent by base station 1. For S1 handover, the target base station discards KeNB* sent by base station 1 and uses the new {NH, NCC} pair sent by the core network to derive a KeNB*. The UE and the target base station then use the KeNB* to derive other keys, such as Krrcint, Krrcenc, Kupenc, etc.

[0213] As can be seen above, during RRC recovery or re-establishment, the base station on the ground must establish a connection not only with the UE but also with the core network. However, in satellite communications, for the aforementioned discontinuous coverage scenario, when a satellite moves to an area where it can serve the UE, it may not be able to communicate with the core network through the NTN gateway. Alternatively, when the satellite can communicate with the core network through the NTN gateway, it may not be able to provide service to the UE. In this case, how the satellite completes security authentication for the UE to access the satellite is crucial for the UE's subsequent communications.

[0214] In view of this, the present application provides an NTN communication method and communication device, which can quickly achieve terminal access through a first identifier and improve communication efficiency.

[0215] It should be understood that the embodiments shown below use terminal devices and network devices as examples of the execution subjects of the interactive illustration to illustrate the method, but the present application does not limit the execution subjects of the interactive illustration, as long as it can communicate according to the method provided in the embodiment of the present application by running the program of the code of the method provided in the embodiment of the present application. The execution subjects of the method provided in the embodiment of the present application can be terminal devices and network devices, or functional modules in terminal devices and network devices that can call programs and execute programs. For example, the network device in Figure 5 can also be a chip, chip system, or processor that supports the method that can be implemented by the network device, and can also be a logic module or software that can implement all or part of the network device functions; the terminal device in Figure 5 can also be a chip, chip system or processor that supports the method that can be implemented by the terminal device, and can also be a logic module or software that can implement all or part of the terminal device functions.

[0216] FIG5 is a schematic flow chart of a method for NTN communication provided by the present application. As shown in FIG5 , the method 400 includes the following steps.

[0217] S410: The terminal device obtains a first identifier.

[0218] The first identifier is used to identify a first context of a terminal device related to the first network device.

[0219] Specifically, the first context is a context established by the first network device for the terminal device. For example, a terminal device context (UE context) within an eNB is an information block within the eNB associated with a UE in an active state (or, RRC connected state). This information block is necessary to maintain the services provided by the evolved universal terrestrial radio access (E-UTRAN) to the active UE, and may include: UE status information, security information, UE capability information, the association between the UE and the S1 logical connection, the association between the UE and the X2 logical connection, etc. The eNB UE context is established after the UE enters the active state; alternatively, the eNB UE context is established after the handover target eNB completes the handover resource allocation (handover preparation phase). Security information may include the current KeNB*, the current RRC integrity protection key, and UE status information may include the robustness header compression status, the context of Ethernet header compression, the uplink data compression status, the mapping rules between the saved QoS (Quality of Service) flow and DRB (Data Air Interface Bearer), and one or more of the C-RNTI, cell identifier, and physical cell identifier of the source cell.

[0220] It should be understood that the above terminal device context is only for illustration and this application does not limit its specific content.

[0221] The network device in this application may refer to a satellite, which may have all or part of the functions of a base station.

[0222] The first context may further include at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC. An unused NCC is an NCC that is not used by the first network device, and there may or may not be an unused NCC. The first network device may determine at least one cell that will cover the terminal device based on auxiliary information from multiple satellites, that is, determine at least one cell that can cover the terminal device.

[0223] In this application, a token may also be referred to as a flag (token), a security token, or an integrity protection token. The token corresponding to a cell may refer to shortMAC-I or shortResumeMAC-I. For example, shortMAC-I or shortResumeMAC-I may consist of the 16 least significant bits of the MAC-I of the cell.

[0224] In this application, the key corresponding to the cell may refer to the access layer key KeNB*, which is used to derive the encryption protection and integrity protection keys of the user plane data and RRC signaling, and derive the integrity protection token based on the integrity protection key. For example, KeNB* can be used to derive the integrity protection token short-MACI.

[0225] The next hop (NH) is derived by the core network and the terminal device. This means the NH generated this time will be used to generate the next NH, and the core network will provide the derived NH to the network device. The NCC is the NH link counter, issued by the core network and associated with each network device and next hop. It counts the number of NH key chain derivations and synchronizes the key chains between the terminal device and the network device. This is used to determine whether the next KeNB* is derived from the current KeNB or a new NH.

[0226] Taking the first cell as an example, the key corresponding to the first cell is the access layer key KeNB* of the first cell, and the NCC corresponding to the first cell is the NCC corresponding to the key of the first cell.

[0227] It should be understood that the key and NCC corresponding to each cell can be collectively referred to as AS security information corresponding to the cell.

[0228] As an implementation manner, the terminal device obtains the first identifier, including: the terminal device receives the first identifier from the first network device.

[0229] Specifically, the first identifier may be determined by the first network device and sent to the terminal device. For example, the first network device sends an AS SMC message or an RRC connection establishment message to the terminal device, and the message carries the first identifier.

[0230] Optionally, while the first network device sends the first identifier to the terminal device, the first network device and the terminal device each establish an AS security context for access layer security protection of communication between the first network device and the terminal device.

[0231] As another implementation method, the terminal device obtains the first identifier, including: the terminal device determines the first identifier based on at least one of the cell identifier of the first cell, the PCI of the first cell, and the C-RNTI allocated to the terminal device by the first cell, wherein the first cell is the service cell of the terminal device, and the first cell is managed by the first network device.

[0232] Specifically, the terminal device can obtain the cell identifier, PCI, etc. from the broadcast message of the first cell, and obtain the C-RNTI allocated to it by the first cell during the process of establishing an RRC connection with the first network device, so that the first identifier can be determined based on the above information.

[0233] Optionally, after S410, the first network device leaves the area covering the terminal device. One possibility is that the terminal device leaves the RRC connection state and enters the RRC suspension state. Another possibility is that the terminal device is in the RRC connection state, but it is a special RRC connection state. The terminal device suspends all wireless signaling bearers and wireless data bearers, and stops all running timers except T302, T320, T322, T323, T325, T330, and T331.

[0234] It should be understood that in this application, the terminal device obtains the first identifier, which does not include the terminal device obtaining the first identifier from the RRC release message, or in other words, the first network device leaves the area covering the terminal device and does not send an RRC release message to the terminal device.

[0235] In the present application, the network device leaves the area covering the terminal device, which can also be said to be the area where the network device stops serving the terminal device, or the network device stops providing services for the area where the terminal device is located.

[0236] S420: The terminal device sends a first identifier and a first token to the second network device. Correspondingly, the second network device receives the first identifier and the first token.

[0237] Specifically, when the terminal device has an AS security context related to the first network device, the terminal device may send a first identifier and a first token to the second network device, and the first token may be used to verify the terminal device.

[0238] As an example, the first context may include an AS security context. The terminal device has an AS security context related to the first network device, which means that an AS security context is established between the terminal device and the first network device. The AS security context established by the terminal device and the AS security context established by the first network device may include AS security information (such as KeNB* and NCC), security algorithms, security capabilities, etc. used by the terminal device in the service cell. In addition, the AS security context established by the first network device may also include an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC.

[0239] The at least one cell includes a first target cell managed by the second network device, and the first target cell corresponds to a first token. In other words, the token corresponding to the at least one cell includes the first token corresponding to the first target cell.

[0240] Optionally, when the terminal device initiates cell selection, selects the first target cell, and attempts to access the first target cell, according to the above description, one possibility is that the current state of the terminal device is the RRC suspension state, and the terminal device can carry the first identifier and the first token through an RRC connection resumption request (RRCConnectionResumeRequest) message. Another possibility is that the current state of the terminal device is the RRC connection state, and the terminal device can carry the first identifier and the first token through an RRC connection reestablishment request (RRCConnectionReestablishmentRequest) message.

[0241] It should be understood that in this application, the second network device may be the same as or different from the first network device, depending on the mobility of the network device, and this application does not limit it.

[0242] S430: The second network device verifies the terminal device according to the first token and the second token.

[0243] Specifically, the second network device may verify the terminal device according to whether the first token and the second token are identical. If they are identical, the verification is successful; otherwise, the verification fails.

[0244] The second token is determined according to the first context corresponding to the first identifier. There are two possible ways to obtain the second token corresponding to the first target cell in the terminal device context stored in the second network device:

[0245] In one possible implementation, the first context includes the second token. In this implementation, the second network device obtains the second token based on the second token included in the first context. Specifically, the first token identifies the first context, and the first context includes the second token.

[0246] For example, the terminal device derives the first token based on one or more of the stored AS context (which may include the key corresponding to the first cell, the integrity protection algorithm, etc.), the CRNTI allocated by the first cell, the PCI of the first cell, and the cell identifier of the first target cell. The first context sent by the first network device to the second network device includes the token corresponding to the first target cell, which is called the second token for the sake of distinction.

[0247] In another possible implementation, the first context includes a first key. In this implementation, the second network device derives the second token and / or the key of the target cell based on the first context. Specifically, the second network device identifies the first context based on the first identifier, the first context including the first key and the first security algorithm. Further, the second network device generates the second token based on one or more of the first key, the first security algorithm, the CRNTI allocated by the first cell, the PCI of the first cell, and the cell identifier of the first target cell. The second network device determines whether to horizontally or vertically derive the key corresponding to the first target cell based on the first key, the first security algorithm, and an unused NCC.

[0248] The first key is a key used by the first cell, and the first security algorithm is an encryption and / or integrity protection algorithm corresponding to the first cell, that is, a security algorithm used by the first cell. For example, the first key is KeNB* used by the first cell.

[0249] Exemplarily, the second network device directly determines the second token based on the first key included in the AS security context, or the second network device generates the second token based on one or more of the first key, the security algorithm used by the first cell, the CRNTI allocated by the first cell, the PCI of the first cell, and the cell identifier of the first target cell, and / or the second network device determines the key of the first target cell based on the first key included in the AS security context, the security algorithm used by the first cell, and one or more of the possible unused NCCs.

[0250] Optionally, the first context may include both the second token and the first key.

[0251] S440, the terminal device accesses the first target cell.

[0252] Specifically, when the second network device passes the verification, the terminal device can access the first target cell.

[0253] Based on the above scheme, the first identifier can be used to identify the context of the terminal device related to the first network device. When the first network device leaves the area covering the terminal device or stops serving the terminal device, when the second network device covers the terminal device, the terminal device can be verified based on the first identifier and the RRC connection can be re-established, so that the terminal device can access the first target cell managed by the second network device. This can improve access efficiency, reduce access delay, and thus improve communication efficiency.

[0254] On the other hand, the first network device can indicate the first identifier to the terminal device through an AS SMC message or an RRC connection establishment message, or the terminal device can determine the first identifier based on at least one of the cell identifier, PCI and C-RNTI of the first cell, and the second network device can complete the verification of the terminal device based on the first identifier to ensure communication security.

[0255] Optionally, before S410, the method 400 further includes: S401, the first network device sends auxiliary information corresponding to at least one network device to the terminal device, and accordingly, the terminal device receives the auxiliary information.

[0256] The at least one network device supports a store and forward function, and / or the at least one network device has a first context, and the at least one network device includes the second network device and may also include the first network device.

[0257] Specifically, the at least one network device may be a satellite having a store-and-forward communication mode or function, or a satellite having a first context. The assistance information corresponding to the at least one network device may also be referred to as satellite assistance information.

[0258] The auxiliary information includes at least one of the following: satellite footprint information, satellite ephemeris parameter information, satellite service start time information, satellite identification information, and satellite frequency information.

[0259] (a) Satellite footprint information indicates the coverage provided by the satellite cell, such as the elevation angle range and / or radius of an earth moving cell, and the reference point and radius of a quasi-earth fixed cell, where the radius is the distance from the edge of coverage to the reference point.

[0260] (b) Satellite ephemeris parameter information indicates the satellite orbit and satellite position, mainly including the satellite orbit semi-major axis, satellite orbit eccentricity, satellite orbit plane inclination, ascending node right ascension, the angle between the ascending node and perigee, and the time when the satellite passes perigee.

[0261] (c) Satellite service start time information may also be referred to as satellite service information, which indicates the time information at which the satellite provides coverage, such as indicating the ephemeris parameters of an Earth mobile cell to estimate the time from entering coverage to leaving coverage, and indicating the service start time of an Earth-like fixed cell.

[0262] (d) The satellite identifier may be a single identifier corresponding to or shared by multiple satellites, or each satellite may have its own identifier to indicate multiple satellites supporting the store and forward function.

[0263] (e) Satellite frequency information indicates the operating frequency range of the satellite.

[0264] The first network device may send the auxiliary information to the terminal device by broadcasting a system message (such as a system information block (SIB) message).

[0265] Optionally, when the terminal device is in the RRC connection state, the first network device may also send the auxiliary information to the terminal device via an RRC message.

[0266] It should be understood that in the present application, the above auxiliary information can be used by the terminal device to determine that the network device that will provide coverage service to it is the second network device.

[0267] Optionally, before S420, the method 400 further includes: the terminal device determines, based on the auxiliary information, that the second network device is about to cover the terminal device, and then the terminal device initiates cell selection.

[0268] Specifically, when the first network device leaves the area covering the terminal device, the terminal device can determine the network device that will soon cover the terminal device based on the auxiliary information, or determine the time of the next coverage. For example, the terminal device determines that the second network device will next provide coverage for it. Therefore, the terminal device can set and start a timer based on the time when the next coverage will arrive. After the timer expires, the terminal device initiates cell selection and selects the first target cell.

[0269] When the terminal device selects the first target cell, the terminal device may send the first token and the first identifier to the second network device that manages the first target cell to complete the verification of the terminal device, ie, execute S420 and subsequent steps.

[0270] It should be understood that the terminal device determines the network device to be covered and starts cell selection. The terminal device can start cell selection when the next coverage is about to come or when the next coverage starts, and this application does not limit this.

[0271] Based on the above solution, the first network device sends auxiliary information corresponding to at least one network device to the terminal device, so that the terminal device determines that the second network device is about to cover the terminal device to start cell selection, so that it can select the cell managed by the second network device, ensuring the continuity of access and avoiding power consumption caused by excessive invalid cell selection by the terminal device.

[0272] Optionally, before S410, the method 400 further includes: the first network device determining a first identifier.

[0273] In the present application, the first identifier may be referred to as a resume identity (resume ID), which may be used to identify or index a context of a terminal device associated with the first network device.

[0274] Exemplarily, the first network device may determine the first identifier based on at least one of the cell identifier of the serving cell (ie, the first cell) of the terminal device, the PCI of the first cell, and the C-RNTI allocated by the first cell to the terminal device.

[0275] As an embodiment, the first identifier includes second information and / or third information, the second information is used to identify the first network device, and the third information is used to identify the context of the terminal device related to the first network device, or in other words, to identify the context of the terminal device established by the first network device for the terminal device or stored by the first network device.

[0276] For example, the first identifier is a 40-bit field, 20 bits of which are used to identify the eNB (an example of the first network device), and 20 bits of which are used to identify the UE context stored by the eNB. For another example, the first identifier is a 24-bit field, 12 bits of which are used to identify the eNB, and 12 bits of which are used to identify the UE context stored by the eNB. For another example, the first identifier consists of two fields, one field for identifying the eNB, and the other field for identifying the UE context stored by the eNB. For another example, the first identifier consists of one field, which identifies the eNB ID.

[0277] Optionally, the method 400 further includes: the first network device sending the first identifier and the first context to the second network device, and correspondingly, the second network device receiving the first identifier and the first context.

[0278] Specifically, the first network device may send the first context and the first identifier to the target network device via an X2 interface, or may send the first context and the first identifier to the core network via an S1 interface, and the core network may send them to the target network device.

[0279] It should be understood that the first context includes the AS security context, which may include the identifier of at least one cell, so that the core network can send the first identifier and the first context to the network device that manages each cell in the at least one cell, that is, the target network device.

[0280] It should also be understood that when the first identifier and the first context are sent on the X2 interface or the S1 interface, they may be sent through non-terminal device related signaling or through terminal device related signaling.

[0281] Alternatively, the first identifier may be understood as part of the first context, or the first context may include the first identifier. In this case, the first network device sending the first identifier and the first context to the second network device may be replaced by the first network device sending the first context to the second network device, the first context including the first identifier.

[0282] The target network device may be one or more than one target network device, and the target network device includes the second network device.

[0283] Based on the above solution, the first network device sends the first identifier and the first context to the second network device, so that the second network device can verify the terminal device according to the above information to ensure the communication security of the terminal device.

[0284] Optionally, after S440 , the method 400 further includes: the second network device determining a second identifier, where the second identifier is used to identify a second context of a terminal device related to the second network device, and the second context is used to update the first context.

[0285] Specifically, after the terminal device accesses the first target cell managed by the second network device, the context of the terminal device will change and will include relevant information of the second network device and / or the first target cell. Therefore, the second network device can determine a second identifier to identify the latest context it has established for the terminal device, i.e., the second context.

[0286] Among them, the second context can be understood as the new context of the terminal device, and the first context can be understood as the old context of the terminal device. According to the second context, the core network can delete the first context and save the second context. Therefore, the second context can be understood as being used to update the first context.

[0287] Exemplarily, the second identifier includes fourth information and / or fifth information, the fourth information is used to identify the second network device, and the fifth information is used to identify the context of the terminal device related to the second network device.

[0288] For a detailed description of the second identifier, please refer to the first identifier above.

[0289] Optionally, the method 400 further includes: the second network device sending a second identifier to the terminal device.

[0290] The second identifier is carried in at least one of the following messages: an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reconstruction message.

[0291] Optionally, the message carrying the second identifier may also indicate to the terminal device that verification is successful, and the message may be in response to the message sent in S420. In one possibility, when the terminal device sends an RRC connection recovery request in S420, the second network device may send the second identifier via an RRC connection recovery message. In another possibility, when the terminal device sends an RRC connection reestablishment request message in S420, the second network device may send the second identifier via an RRC connection reestablishment message.

[0292] Specifically, the second network device may indicate a second identifier to the terminal device, which is used to identify the context of the terminal device related to the second network device. In other words, the second identifier may be used to update the first identifier.

[0293] Based on the above solution, the second network device can determine the second identifier and indicate the second identifier to the terminal device, so that the terminal device can update the identifier to ensure that subsequent communications proceed normally.

[0294] Optionally, the method 400 further includes: the second network device sending the first information and the second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0295] Specifically, the second network device indicates the correspondence between the first identifier and the second identifier to the core network. Further, the core network can update the context of the terminal device to the second context based on the correspondence, and save the second identifier corresponding to the context, that is, update the identifier corresponding to the terminal device context.

[0296] Based on the above solution, the second network device can indicate the second context and the correspondence between the first identifier and the second identifier to the core network, so that the core network can update the terminal device context and the corresponding identifier to ensure that subsequent communications proceed normally.

[0297] FIG6 is another schematic flow chart of a method for NTN communication provided by the present application. As shown in FIG6 , the method 500 includes the following steps.

[0298] S510: The terminal device obtains a first identifier.

[0299] The first identifier is used to identify a first context of a terminal device related to the first network device.

[0300] Specifically, the specific meaning of the first context can refer to method 400. The difference from method 400 is that in method 500, the first context may not include the identifier of at least one cell that is about to cover the terminal device, the token corresponding to at least one cell, the key corresponding to at least one cell, the NCC corresponding to at least one cell, and the unused NCC.

[0301] As an implementation manner, S510, the terminal device obtains the first identifier, including: the terminal device receives the first identifier from the first network device.

[0302] Specifically, the first identifier may be determined by the first network device and sent to the terminal device. For example, the first network device sends an RRC connection establishment message to the terminal device, and the message carries the first identifier.

[0303] As another implementation, S510, the terminal device obtains the first identifier, including: the terminal device determines the first identifier according to at least one of the cell identifier of the first cell, the PCI of the first cell, and the C-RNTI allocated by the first cell to the terminal device.

[0304] Specifically, the terminal device can obtain the cell identifier, PCI, etc. from the broadcast message of the first cell, and obtain the C-RNTI allocated to it by the first cell during the process of establishing an RRC connection with the first network device, so that the first identifier can be determined based on the above information.

[0305] Optionally, after S510, the first network device leaves the area covering the terminal device. One possibility is that the terminal device leaves the RRC connection state and enters the RRC suspension state. Another possibility is that the terminal device is in the RRC connection state, but it is a special RRC connection state. The terminal device suspends all wireless signaling bearers and wireless data bearers, and stops all running timers except T302, T320, T322, T323, T325, T330, and T331.

[0306] It should be understood that, in the present application, the terminal device obtains the first identifier, which does not include the terminal device obtaining the first identifier from the RRC release message, or in other words, the terminal device does not receive the RRC release message.

[0307] S520: The second network device sends a paging message or a PDCCH command to the terminal device. Correspondingly, the terminal device receives the paging message or the PDCCH command.

[0308] In one implementation, when the second network device covers the terminal device, the second network device may wake up the terminal device through a PDCCH command to initiate random access.

[0309] Figure 7 is a schematic diagram of a paging process. As shown in Figure 7, the process includes all or part of the following steps.

[0310] S601, UE is in RRC idle state.

[0311] Specifically, when the UE initiates access, the core network will include the UE's tracking area (TA) list in the NAS message of the registration acceptance. After the UE enters the RRC connected state and the inactivity timer expires, the UE will enter the RRC idle state.

[0312] S602: The core network sends a paging message.

[0313] When the core network needs to page a UE, it sends a paging message to all cells in the TA identity (TAI) list where the UE is located. The paging message includes the UE's international mobile subscriber identity (IMSI) or service-temporary mobile subscriber identity (S-TMSI).

[0314] S603: Establish an RRC connection.

[0315] After receiving the paging message, if the IMSI or S-TMSI in the paging message matches the UE, the UE initiates random access to enter the RRC connected state.

[0316] The above is the core network paging mechanism of LTE. In addition to the core network paging mechanism, 5G also introduces RAN paging. When the RAN side needs to page a UE, it will send a paging message containing the UE's inactive radio network temporary identifier (I-RNTI) to all cells in the RNA where the UE is located. After the UE receives this paging message, if the I-RNTI in the paging message matches it, the RRC recovery process is initiated to enter the RRC connected state.

[0317] In this implementation, the first identifier may be included in the paging message, for example, the IMSI, S-TMSI or I-RNTI in S602 is replaced with the first identifier, and the terminal device is paged via the first identifier to wake up the terminal device and initiate random access.

[0318] In another implementation, when the second network device covers the terminal device, the second network device may wake up the terminal device through a PDCCH command to initiate random access.

[0319] For example, if a UE is in an RRC connected state and experiences uplink desynchronization, and has downlink data to transmit, the base station initiates a PDCCH command. When the UE blindly detects the PDCCH and finds it to be a PDCCH command, it triggers random access. The blind detection process includes: the UE determines the PDCCH (downlink control information (DCI)) range through predefined parameters or signaling messages. Within this range, the UE attempts to use many different types of parameters (such as control channel element (CCE) index, aggregation level, and radio network temporary identifier (RNTI)) to decode the PDCCH or DCI based on a trial-and-error method. Specifically, the UE calculates the corresponding CCE index based on information in the search space and decodes candidate PDCCHs one by one based on the CCE index. If the cyclic redundancy check (CRC) is correct, the UE determines that the PDCCH is valid, processes the corresponding information, and successfully obtains the DCI. If the check fails, the UE determines that the candidate PDCCH is invalid or occupied by another UE and attempts to decode other candidate PDCCHs.

[0320] Figure 8 is a schematic diagram of a random access process triggered by a PDCCH command. As shown in Figure 8, the process includes all or part of the following steps.

[0321] S701: The UE is in the RRC connected state and starts a timer.

[0322] When a UE is in the RRC Connected state and has no data transmission, the UE starts the Timing Advance Timer (TAT). Due to the lack of data activity, the RRC Inactive Timer (RRC Inactive Timer) also starts. Assuming the RRC Inactive Timer has not expired and the RRC Connected state remains intact for the entire duration, if the TAT times out, the UE is considered to have lost uplink synchronization. At this point, the UE releases all PUCCH (including scheduling resources, channel quality indication (CQI) configuration) and sounding reference signal (SRS) resources, but remains in the RRC Connected state. When the eNB has downlink data to send, the UE needs to reacquire uplink time synchronization and reconfigure PUCCH / SRS resources for the UE.

[0323] S702: The eNB sends a PDCCH command to the UE using a DCI format to instruct the UE to use a random access (RA) preamble included in the DCI to perform contention-free RA.

[0324] S703: The UE detects the PDCCH command scrambled by the C-RNTI, and sends a random access preamble.

[0325] S704, the eNB sends a random access channel (RACH) response with a timing advance (TA) value so that the UE can achieve uplink synchronization.

[0326] S705 , the eNB sends an RRC reconfiguration message, which carries the PUCCH or SRS.

[0327] S706: The UE sends an RRC reconfiguration complete message to confirm the resumption of uplink / downlink data transmission.

[0328] In this implementation, the first identifier may be used to scramble the PDCCH command, for example, the C-RNTI used in S703 is replaced with the first identifier, so as to wake up the terminal device and initiate random access.

[0329] S530, the terminal device receives the paging message according to the first identifier; or decodes the PDCCH command according to the first identifier.

[0330] Specifically, the terminal device may determine a paging occasion (PO) based on the first identifier, thereby receiving a paging message at the paging occasion. Alternatively, the terminal device may use the first identifier as a scrambling code to descramble the PDCCH command, thereby obtaining the content of the PDCCH command.

[0331] Based on the above scheme, the first identifier can be used to identify the first context of the terminal device related to the first network device. When the first network device stops serving the area of ​​the terminal device and the second network device serves the area of ​​the terminal device, the second network device can wake up the terminal device for access based on the first identifier, for example, waking up the terminal device to initiate random access and establish an RRC connection. This can improve access efficiency, reduce access delay, and thus improve communication efficiency.

[0332] Optionally, in method 500, the terminal device does not have an AS security context associated with the first network device. In other words, since the terminal device does not have an AS security context associated with the first network device, the second network device can wake up the terminal device through S520 to initiate random access, establish an RRC connection, and establish an AS security context with the second network device.

[0333] Optionally, in method 500, the terminal device has an AS security context associated with the first network device. In other words, when the terminal device has an AS security context associated with the first network device, the terminal device can actively initiate cell selection (specifically, refer to method 400) to access the first target cell, or the second network device can wake up the terminal device through S520 to initiate random access, thereby allowing the terminal device to access the first target cell managed by the second network device.

[0334] Optionally, before S510, the method 500 further includes: S501, the first network device sends auxiliary information corresponding to at least one network device to the terminal device, and accordingly, the terminal device receives the auxiliary information.

[0335] For details of S501, please refer to S401 and will not be described in detail here.

[0336] Optionally, the method 500 further includes: the terminal device determines, based on the auxiliary information, that the second network device is about to cover the terminal device, and then the terminal device initiates cell selection.

[0337] Specifically, when the first network device leaves the area covering the terminal device, the terminal device can determine the network device that will soon cover the terminal device based on the auxiliary information, or determine the time of the next coverage. For example, the terminal device determines that the second network device will next provide coverage for it. Therefore, the terminal device can set and start a timer based on the time when the next coverage will arrive. After the timer expires, the terminal device initiates cell selection.

[0338] It should be understood that the terminal device determines the network device to be covered and starts cell selection. The terminal device can start cell selection when the next coverage is about to come or when the next coverage starts, and this application does not limit this.

[0339] Optionally, the method 500 further includes: the first network device determining a first identifier. The specific method for the first network device to determine the first identifier can refer to the method 400 and will not be described in detail here.

[0340] Optionally, the method 500 further includes: the first network device sending the first identifier and the first context to the second network device, and correspondingly, the second network device receiving the first identifier and the first context.

[0341] The specific process of the first network device sending the first identifier and the first context to the second network device can be referred to method 400 and will not be described in detail here.

[0342] Optionally, the method 500 further includes: the second network device determining a second identifier, the second identifier being used to identify a second context of a terminal device related to the second network device, and the second context being used to update the first context.

[0343] Exemplarily, in method 500 , the second context may include an AS security context of a terminal device related to the second network device. For specific content of the AS security context, reference may be made to method 400 .

[0344] In one implementation, the second identifier may be used to update the first identifier.

[0345] Optionally, the method 400 further includes: the second network device sending a second identifier to the terminal device.

[0346] The second identifier is carried in at least one of the following messages: AS SMC message, RRC connection establishment message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

[0347] In one example, since the terminal device has not established an AS security context in the first cell, the second network device may also indicate the second identifier through an AS SMC message when establishing an AS security context with the terminal device; in another example, since the terminal device has established an AS security context in the first cell, RRC connection reconstruction or RRC connection recovery is initiated in S603, and the second network device may indicate the second identifier through an RRC reconfiguration message, an RRC connection recovery message, or an RRC connection reconstruction message.

[0348] Optionally, the method 400 further includes: the second network device sending the first information and the second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

[0349] The specific method for the second network device to send the first information and the second context to the core network can refer to method 400 and will not be described in detail here.

[0350] FIG9 is a schematic flow chart of a method for NTN communication provided in the present application. The method 800 shown in FIG9 can be regarded as a specific implementation of the method 400. As shown in FIG9 , the method 800 includes the following steps.

[0351] S801, UE (an example of terminal equipment) obtains auxiliary information of at least one satellite.

[0352] For example, eNB1 (an example of the first network device, also referred to as satellite 1) indicates the auxiliary information to the UE via a broadcast system message. For another example, eNB1 indicates the auxiliary information to the UE in the RRC connected state via an RRC message.

[0353] Among them, S801 may refer to S401 for details.

[0354] S802, the UE requests to establish a connection, initiates access, and establishes an RRC connection with eNB1.

[0355] The UE-initiated access process specifically includes:

[0356] 1) The UE sends message 1 (Msg1) to initiate RA. Message 1 includes an RA preamble.

[0357] 2) eNB1 sends message 2 (Msg2), ie, RA response, to the UE.

[0358] 3) The UE sends an RRC Connection Request message to the eNB1, which carries the UE identifier.

[0359] It should be understood that this message corresponds to message 3 (Msg3) of the RA process, and during the RRC establishment process, Msg3 transmits an RRC connection request message).

[0360] In addition, the UE identifier carried in Msg3 varies depending on the UE status and application scenario. For example, if the UE has previously connected to a cell, the UE identifier can be the C-RNTI of the cell, which is unique in the cell. For another example, if the UE has not previously connected to a cell, the UE identifier can be the S-TMSI or a random number. Specifically, if the upper layer provides the S-TMSI, the UE identifier can be the S-TMSI information; otherwise, the UE can generate a random number as the UE identifier.

[0361] After the UE sends Msg3, eNB1 establishes a context for the UE and allocates SRB1 resources. If SRB1 resource allocation fails, eNB1 responds with an RRCConnectionReject message to the UE, indicating that the RRC connection establishment process failed. If RRC establishment succeeds, proceed to step 4).

[0362] 4) eNB1 replies to the UE with an RRC Connection Establishment message, which carries detailed information about the SRB1 resource configuration and is used to establish SRB1. This message corresponds to Message 4 (Msg4) in the RA process. During the RRC establishment process, Msg4 transmits the RRC Connection Establishment message.

[0363] Optionally, as an implementation manner, the RRC connection establishment message includes an identifier #1 (an example of the first identifier in method 400), which is used to identify the context established by eNB1 for the UE. For details, please refer to S410.

[0364] 5) The UE configures radio resources according to the SRB1 resource information indicated in the RRC connection setup message, and then sends an RRC connection setup complete (RRCConnectionSetupComplete) message to eNB1. After eNB1 receives the message, the RRC connection setup is completed.

[0365] Optionally, if the UE is in the RRC connected state in S801, S802 does not need to be executed.

[0366] After the RRC connection is established, when eNB1 is connected to the CN, the UE and eNB1 establish an AS security context, which specifically includes S803-S807.

[0367] S803, eNB1 transparently transmits the NAS message between the UE and the CN, completing the NAS security mode and registration process.

[0368] S804: CN sends an initial context establishment request message to eNB1.

[0369] The message includes the access layer key KeNB, and the message can be used to start the initial context establishment process. KeNB can be used to derive KeNB*.

[0370] S805, eNB1 sends an AS SMC message to the UE.

[0371] The message includes integrity protection and encryption algorithms, and can be used to notify the UE to start the integrity protection and encryption process.

[0372] Optionally, as another implementation manner, the AS SMC message includes an identifier #1, which is used to identify the context established by eNB1 for the UE. For details, please refer to S410.

[0373] S806: eNB1 and UE establish an AS security context.

[0374] Specifically, the UE derives a key based on the integrity protection and encryption algorithm indicated by the AS SMC message, and eNB1 and the UE establish an AS security context. The AS security context of the UE and eNB1 may include the AS security information (such as KeNB* and NCC), security algorithm, and security capabilities used by the UE in the serving cell (an example of the first cell). It may also include one or more cells that will cover the UE (which may be one or more), the shortMAC-I corresponding to the cell, the AS security information corresponding to the cell (such as KeNB* and NCC), and unused NCC.

[0375] The AS security context is included in the UE context. In other words, the identifier #1 can be used to identify the AS security context established by eNB1 for the UE.

[0376] Optionally, as another implementation method, the UE generates identifier #1 based on one or more of the cell identifier of the serving cell, PCI and C-RNTI allocated by the serving cell, which is used to identify the context established by eNB1 for the UE. For details, please refer to S410.

[0377] Optionally, the UE context also includes identifier #1.

[0378] S807, eNB1 sends the identifier #1 and the UE context to the target base station, for example, the target base station includes eNB2 (an example of the second network device, also referred to as satellite 2).

[0379] Specifically, the eNB1 may send the message directly to the target base station, or may first send the message to the CN and then forward the message to the target base station by the CN.

[0380] Furthermore, the target base station may save the identifier #1 and the UE context.

[0381] Among them, eNB2 can be the same as or different from eNB1.

[0382] Specifically, S807 may refer to the process in method 400 where the first network device sends the first identifier and the first context to the second network device.

[0383] S808: The UE initiates cell selection.

[0384] When eNB1 is about to enter or stop service, one possibility is that the UE leaves the RRC connected state and enters the RRC suspended state. Another possibility is that the UE remains in the RRC connected state, but suspends all SRBs and DRBs and stops all running timers except T302, T320, T322, T323, T325, T330, and T331, which is a special RRC connected state.

[0385] The UE determines the time of next coverage based on the auxiliary information obtained in S801 to start cell selection. For example, the UE selects cell #1 managed by eNB2 (ie, an example of the first target cell).

[0386] After the UE completes cell selection, the eNB2 verifies the UE based on the AS security context, specifically including S809 and S810.

[0387] S809, the UE sends the identifier #1 and shortMAC-I #1 (an example of the first token) to the eNB2.

[0388] The shortMAC-I#1 may be obtained by the UE based on the AS security context established for it by the eNB1.

[0389] Specifically, according to the RRC state of the UE in S808, if the UE is in the RRC suspended state, the UE sends the identifier #1 and shortMAC-I#1 through the RRC connection recovery request message; if the UE is in the RRC connected state, the UE sends the identifier #1 and shortMAC-I#1 through the RRC connection reestablishment request (RRCConnectionReestablishmentRequest) message.

[0390] Among them, S809 may refer to S420 for details.

[0391] S810, eNB2 verifies the UE based on identity #1.

[0392] Specifically, eNB2 can retrieve its stored UE context based on identifier #1, where the UE context includes the shortMAC-I of cell #1 (denoted as shortMAC-I#2, an example of the second token), or the UE context includes the KeNB* of cell #1 (an example of the first key). eNB2 determines shortMAC-I#2 based on the KeNB* of cell #1. Further, based on whether shortMAC-I#2 is the same as shortMAC-I#1, it can determine whether the UE is authenticated. If the authentication is successful, S811 can be executed. If the authentication fails, eNB2 can indicate the authentication failure to the UE through an RRC message.

[0393] Among them, S810 may refer to S430 for details.

[0394] S811, eNB2 indicates identifier #2 (an example of the second identifier of method 400) to the UE.

[0395] Identifier #2 identifies the context established by eNB2 for the UE, which can be used to update the context established by eNB1 for the UE. In other words, after eNB1 establishes the context for the UE, the UE selects cell #1 managed by eNB2. Therefore, the new UE context will include relevant information about eNB2 and / or cell #1.

[0396] Specifically, identifier #2 can be sent through an RRC reconfiguration message, or through an RRC connection recovery message or an RRC connection reconstruction message, and the RRC connection recovery message and the RRC connection reconstruction message respectively respond to the RRC connection recovery request message or the RRC connection reconstruction request message sent by the UE in S809.

[0397] Optionally, when eNB2 indicates identifier #2 to the UE, it may also indicate to the UE that the verification is successful.

[0398] S812: CN and / or other target base stations update UE context.

[0399] Specifically, eNB2 can send the new UE context and identity #2 to the CN. eNB2 can also indicate the correspondence between identity #2 and identity #1 to the CN. Based on the correspondence between identity #2 and identity #1, the CN can process the historical UE context, for example, deleting the UE context corresponding to identity #1 and saving identity #2 and the new UE context. Other target base stations can process the historical UE context through the network. For example, the CN notifies other target base stations to process the historical UE context. Alternatively, eNB2 can also send the new UE context and identity #2 to other target base stations, and indicate the correspondence between identity #2 and identity #1.

[0400] FIG10 is a schematic flow chart of a method for NTN communication provided in the present application. The method 900 shown in FIG10 can be regarded as a specific implementation of the method 500. As shown in FIG10 , the method 900 includes the following steps.

[0401] S901, UE (an example of a terminal device) obtains auxiliary information of at least one satellite.

[0402] Specifically, S901 may refer to S801 and S501.

[0403] S902, the UE initiates access and establishes an RRC connection with eNB1.

[0404] For details about SS902, please refer to SS802.

[0405] Among them, the RRC connection establishment message includes identifier #3 (an example of the first identifier in method 500), which is used to identify the context established by eNB1 for the UE, or the UE generates identifier #3 based on one or more of the cell identifier, PCI and C-RNTI allocated to it by the serving cell. For details, please refer to S410, S510 and S802.

[0406] In method 900, after the RRC connection is established, the UE and eNB1 do not establish an AS security context. For example, after the RRC connection is established, eNB1 is not connected to the core network, and eNB1 cannot complete the initial UE context establishment process, and thus the UE and eNB1 cannot establish an AS security context.

[0407] S903, eNB1 sends identifier #3 and UE context to the target base station. For example, the target base station includes eNB2 (an example of the second network device, also called satellite 2). The UE context does not include the AS security context.

[0408] Among them, S903 may refer to S807 for details.

[0409] S904: The UE initiates cell selection.

[0410] Among them, S904 can refer to S808.

[0411] Next, the eNB2 wakes up the UE to initiate random access, which specifically includes S905 and S906.

[0412] S905, eNB2 sends a paging message or a PDCCH command to the UE.

[0413] The paging message includes the identifier #3, or the PDCCH command is scrambled by the identifier #3.

[0414] Among them, S905 may refer to S520 for details.

[0415] S906: The UE receives a paging message or decodes a PDCCH command based on the identifier #1.

[0416] Among them, S906 may refer to S530 for details.

[0417] S907: The UE initiates random access and establishes a context for the UE with the eNB2 and the CN.

[0418] Specifically, the UE may initiate random access according to the configuration information in the PDCCH command of the paging message and access the cell #2 managed by eNB2. For the specific random access process, please refer to S802.

[0419] Furthermore, the UE, eNB2 and CN may jointly establish a context for the UE, for example, establish an AS security context. For details, please refer to S803-S807.

[0420] During the process of establishing the UE context, the UE and / or eNB2 may determine identifier #4 (an example of the second identifier of method 500 ), which is used to identify the context established by eNB2 for the UE. Optionally, the context includes an AS security context.

[0421] S908, eNB2 indicates identifier #4 to the UE.

[0422] S909: CN and / or other target base stations update UE context.

[0423] For details of S908 and S909, please refer to S811 to S812.

[0424] It is understood that, in order to implement the functions in the above embodiments, the base station and the terminal include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in conjunction with the units and method steps of the various examples described in the embodiments disclosed in this application, this application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0425] Figures 11 and 12 are schematic diagrams of the structures of communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal or base station in the above-mentioned method embodiments, thereby also achieving the beneficial effects possessed by the above-mentioned method embodiments. In the embodiments of the present application, the communication device can be a terminal device as shown in Figure 1 or Figure 2, or a satellite as shown in Figure 1 or Figure 2, or a module (such as a chip) applied to a terminal device or satellite.

[0426] As shown in FIG. 11 , the communication device 2000 includes a processing unit 2010 and a transceiver unit 2020 .

[0427] In one implementation, the communication apparatus 2000 is used to implement the functions of the terminal device or the network device in the method 400 shown in FIG. 5 or the method 800 shown in FIG. 9 .

[0428] For example, the communication device 2000 is used to implement the functions of the terminal device in the method 400 shown in Figure 5 or the method 800 shown in Figure 9. Specifically, the processing unit 2010 is used to: obtain a first identifier, the first identifier is used to identify a first context of the terminal device related to the first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC; the transceiver unit 2020 is used to: when the terminal device has an access layer security context related to the first network device, send the first identifier and the first token to the second network device, the first token is used to verify the terminal device, the first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by the second network device; the processing unit 2010 is also used to: access the first target cell.

[0429] It should be understood that the transceiver unit 2010 and the processing unit 2020 can also perform other operations performed by the terminal device in the above-mentioned method 400 or method 800, which are not described in detail here.

[0430] For another example, the communication device 2000 is used to implement the functions of the second network device in the method 400 shown in Figure 5 or the method 800 shown in Figure 9. Specifically, the transceiver unit 2020 is used to: receive a first identifier and a first token from the terminal device, the first identifier is used to identify a first context of the terminal device related to the first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, an unused NCC, the first target cell corresponding to the first token, and at least one cell including the first target cell managed by the second network device; the processing unit 2010 is used to: determine the second token based on the first context corresponding to the first identifier, and verify the terminal device based on the first token and the second token.

[0431] It should be understood that the transceiver unit 2010 and the processing unit 2020 may also perform other operations performed by the second network device in the above method 400 or method 800, which are not described in detail here.

[0432] For another example, the communication device 2000 is used to implement the functions of the first network device in the method 400 shown in Figure 5 or the method 800 shown in Figure 9. Specifically, the processing unit 2010 is used to: determine a first identifier, the first identifier is used to identify a first context of a terminal device related to the first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to at least one cell, a key corresponding to at least one cell, an NCC corresponding to at least one cell, and an unused NCC; and the transceiver unit 2020 is used to: send the first identifier to the terminal device and the second network device.

[0433] It should be understood that the transceiver unit 2010 and the processing unit 2020 may also perform other operations performed by the first network device in the above method 400 or method 800, which are not described in detail here.

[0434] In another implementation, the communication apparatus 2000 is used to implement the functions of the terminal device or the network device in the method 500 shown in FIG. 6 or the method 900 shown in FIG. 10 .

[0435] For example, the communication device 2000 is used to implement the functions of the terminal device in the method 500 shown in FIG6 or the method 900 shown in FIG10. Specifically, the processing unit 2010 is used to: obtain a first identifier, the first identifier being used to identify a first context of the terminal device associated with the first network device; the transceiver unit 2020 is used to: receive a paging message or a PDCCH command from the second network device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier; the processing unit 2010 is further used to: receive the paging message according to the first identifier; or decode the PDCCH command according to the first identifier.

[0436] It should be understood that the transceiver unit 2010 and the processing unit 2020 can also perform other operations performed by the terminal device in the above-mentioned method 500 or method 900, which are not described in detail here.

[0437] For another example, the communication device 2000 is used to implement the functions of the second network device in the method 500 shown in Figure 6 or the method 900 shown in Figure 10. Specifically, the transceiver unit 2020 is used to receive a first identifier from the first network device, where the first identifier is used to identify a first context of a terminal device associated with the first network device; and the processing unit 2010 is used to: when the second network device covers the terminal device, send a paging message or a PDCCH command to the terminal device, where the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier.

[0438] It should be understood that the transceiver unit 2010 and the processing unit 2020 may also perform other operations performed by the second network device in the above method 500 or method 900, which are not described in detail here.

[0439] For another example, the communication device 2000 is configured to implement the functions of the first network device in the method 500 shown in FIG6 or the method 900 shown in FIG10. Specifically, the processing unit 2010 is configured to: determine a first identifier, the first identifier being used to identify a first context of a terminal device associated with the first network device; and the transceiver unit 2020 is configured to send the first identifier to the terminal device and the second network device.

[0440] It should be understood that the transceiver unit 2010 and the processing unit 2020 may also perform other operations performed by the first network device in the above method 500 or method 900, which are not described in detail here.

[0441] As shown in Figure 12, the communication device 3000 includes a processor 3010 and an interface circuit 3020. The processor 3010 and the interface circuit 3020 are coupled to each other. It is understood that the interface circuit 3020 can be a transceiver or an input / output interface. Optionally, the communication device 3000 may also include a memory 3030 for storing instructions executed by the processor 3010, or storing input data required by the processor 3010 to execute instructions, or storing data generated after the processor 3010 executes instructions. Sometimes, the interface circuit 3020 can also be understood as part of the processor 3010, in which case the communication device 3000 includes the processor 3010.

[0442] When the communication device 3000 is used to implement the method shown in any one of Figures 5 to 10, the processor 3010 is used to implement the functions of the above-mentioned processing unit 2010, and the interface circuit 3020 is used to implement the functions of the above-mentioned transceiver unit 2020.

[0443] When the above-mentioned communication device is a chip applied to a terminal device (referred to as a terminal chip for short), the terminal chip implements the functions of the terminal device in the above-mentioned method embodiment. When the terminal chip receives information from other devices (such as the first network device or the second network device), it can be understood that the information is first received by other modules in the terminal device (such as a radio frequency module or an antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to other devices, it can be understood that the information is first sent to other modules in the terminal device (such as a radio frequency module or an antenna) and then sent to other devices by these modules.

[0444] When the above-mentioned communication device is a chip applied to the first network device or the second network device (referred to as a network chip for short), the network chip implements the functions of the first network device or the second network device in the above-mentioned method embodiment. The network chip receives information from other devices (such as terminal devices or core networks), which can be understood as the information being first received by other modules (such as radio frequency modules or antennas) in the first network device or the second network device, and then sent to the network chip by these modules. The network chip sends information to other devices, which can be understood as the information being first sent to other modules (such as radio frequency modules or antennas) in the first network device or the second network device, and then sent to other devices by these modules.

[0445] In the present application, when device A sends information to device B, it can be that A sends it directly to B, or that A sends it indirectly to B through other devices. Similarly, when device B receives information from device A, it can be that device B directly receives the information sent by device A, or that device B indirectly receives the information sent by device A through other devices. Devices A and B here can be network devices or terminal devices, or modules inside network devices or terminal devices. The sending and receiving of information can be information interaction between network devices or terminal devices, for example, information interaction between a satellite and a UE; the sending and receiving of information can also be information interaction between two network devices, for example, information interaction between a CU and a DU; the sending and receiving of information can also be information interaction between different modules within a device, for example, information interaction between a terminal chip and other modules on the terminal device, or information interaction between a network chip and other modules in the network device.

[0446] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0447] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM 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. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0448] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may 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 program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0449] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0450] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0451] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

[0452] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for non-terrestrial network communication, characterized in that: include: Obtain a first identifier, where the first identifier is used to identify a first context of a terminal device associated with a first network device, where the first context includes at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; When the terminal device has an access layer security context associated with the first network device, sending the first identifier and a first token to the second network device, where the first token is used to verify the terminal device, a first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by the second network device; Access the first target cell.

2. The method according to claim 1, characterized in that The obtaining of the first identifier includes: Receive the first identifier from the first network device.

3. The method according to claim 2, characterized in that The first identifier is carried in at least one of the following messages: Access layer security mode command message, RRC connection establishment message.

4. The method according to claim 1, wherein The obtaining of the first identifier includes: The first identifier is determined based on at least one of a cell identifier of a first cell, a physical cell identifier of the first cell, and a cell radio network temporary identifier allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: receiving auxiliary information corresponding to at least one network device, where the at least one network device supports a store and forward function and / or the at least one network device has the first context, and the at least one network device includes the second network device; determining, according to the auxiliary information, that the second network device is about to cover the terminal device; Start cell selection.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: Receive a second identifier from the second network device, where the second identifier is used to identify a second context of the terminal device related to the second network device, and the second identifier is carried in at least one of the following messages: an access layer security mode command message, an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reconstruction message.

7. A method for non-terrestrial network communication, characterized in that: include: Receiving a first identifier and a first token from a terminal device, where the first identifier is used to identify a first context of the terminal device associated with a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; a first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by a second network device; determining a second token according to the first context corresponding to the first identifier; The terminal device is authenticated based on the first token and the second token.

8. The method according to claim 7, characterized in that The method further comprises: receiving the first context and the first identifier from the first network device, the first context including the second token; The determining the second token according to the first context corresponding to the first identifier includes: The second token is retrieved from the first context according to the first identifier.

9. The method according to claim 7, characterized in that The method further comprises: receiving the first context and the first identifier from the first network device, wherein the first context includes a first key; The determining the second token according to the first context corresponding to the first identifier includes: Retrieving the first key from the first context according to the first identifier; The second token is generated according to the first key.

10. The method according to any one of claims 7 to 9, characterized in that The method further comprises: Determine a second identifier, where the second identifier is used to identify a second context of the terminal device associated with the second network device, and the second context is used to update the first context; The second identifier is sent to the terminal device, where the second identifier is carried in at least one of the following messages: an access layer security mode command message, an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reconstruction message.

11. The method according to claim 10, characterized in that The method further comprises: Sending first information and the second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

12. A method for non-terrestrial network communication, characterized in that: include: Determine a first identifier, where the first identifier is used to identify a first context of a terminal device associated with a first network device, where the first context includes at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; Send the first identifier to the terminal device and the second network device.

13. The method according to claim 12, characterized in that The first identifier is carried in at least one of the following messages: Access layer security mode command message, RRC connection establishment message.

14. The method according to claim 12 or 13, characterized in that The method further comprises: Auxiliary information corresponding to at least one network device is sent to the terminal device, where the at least one network device supports a store and forward function and / or the at least one network device has the first context.

15. The method according to any one of claims 12 to 14, characterized in that The method further comprises: Send the first context and the first identifier to the second network device and the core network.

16. A method for non-terrestrial network communication, characterized in that: include: Obtaining a first identifier, where the first identifier is used to identify a first context of a terminal device associated with the first network device; receiving a paging message or a PDCCH command from a second network device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier; Answer the paging message according to the first identifier; or The PDCCH command is decoded according to the first identifier.

17. A method for non-terrestrial network communication, characterized in that: include: Receiving a first identifier from a first network device, where the first identifier is used to identify a first context of a terminal device associated with the first network device; When the second network device covers the terminal device, a paging message or a PDCCH command is sent to the terminal device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier.

18. A method for non-terrestrial network communication, characterized in that: include: Determining a first identifier, where the first identifier is used to identify a first context of a terminal device associated with the first network device; The first identifier is sent to the terminal device and the second network device, and the first network device and / or the second network device supports a store and forward function.

19. A communication device, characterized in that: include: A processing unit, configured to obtain a first identifier, where the first identifier is used to identify a first context of a terminal device associated with a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; a transceiver unit, configured to send the first identifier and a first token to the second network device when the terminal device has an access layer security context associated with the first network device, wherein the first token is used to verify the terminal device, the first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by the second network device; The processing unit is further configured to: access the first target cell.

20. The device according to claim 19, characterized in that The processing unit is specifically configured to: Receive the first identifier from the first network device.

21. The device according to claim 20, characterized in that The first identifier is carried in at least one of the following messages: Access layer security mode command message, RRC connection establishment message.

22. The device according to claim 19, characterized in that The processing unit is specifically configured to: The first identifier is determined based on at least one of a cell identifier of a first cell, a physical cell identifier of the first cell, and a cell radio network temporary identifier allocated by the first cell to the terminal device, wherein the first cell is a service cell of the terminal device managed by the first network device.

23. The device according to any one of claims 19 to 22, characterized in that The transceiver unit is further configured to: receive auxiliary information corresponding to at least one network device, the at least one network device supporting a store and forward function, and / or the at least one network device having the first context, the at least one network device including the second network device; The processing unit is further configured to: determine, based on the auxiliary information, that the second network device is about to cover the terminal device, and initiate cell selection.

24. The device according to any one of claims 19 to 23, characterized in that The transceiver unit is further configured to: Receive a second identifier from the second network device, where the second identifier is used to identify a second context of the terminal device related to the second network device, and the second identifier is carried in at least one of the following messages: an access layer security mode command message, an RRC reconfiguration message, an RRC connection recovery message, and an RRC connection reconstruction message.

25. A communication device, characterized in that: include: A transceiver unit, configured to receive a first identifier and a first token from a terminal device, where the first identifier is used to identify a first context of the terminal device associated with a first network device, the first context including at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; a first target cell corresponds to the first token, and the at least one cell includes the first target cell managed by a second network device; a processing unit, configured to determine a second token according to the first context corresponding to the first identifier; The terminal device is verified according to the first token and the second token.

26. The device according to claim 25, characterized in that The transceiver unit is further configured to: receive the first context and the first identifier from the first network device, wherein the first context includes the second token; The processing unit is specifically configured to retrieve the second token from the first context according to the first identifier.

27. The device according to claim 25, characterized in that The transceiver unit is further configured to: receive the first context and the first identifier from the first network device, where the first context includes a first key; The processing unit is specifically configured to: retrieve the first key from the first context according to the first identifier; and generate the second token according to the first key.

28. The device according to any one of claims 25 to 27, characterized in that The processing unit is further configured to: determine a second identifier, the second identifier being used to identify a second context of the terminal device associated with the second network device, the second context being used to update the first context; The transceiver unit is also used to: send the second identifier to the terminal device, and the second identifier is carried in at least one of the following messages: access layer security mode command message, RRC reconfiguration message, RRC connection recovery message, and RRC connection reconstruction message.

29. The device according to claim 28, characterized in that The transceiver unit is further configured to: Sending first information and the second context to the core network, where the first information is used to indicate a correspondence between the first identifier and the second identifier.

30. A communication device, characterized in that: include: a processing unit, configured to determine a first identifier, where the first identifier is used to identify a first context of a terminal device associated with a first network device, where the first context includes at least one of the following: an identifier of at least one cell that will cover the terminal device, a token corresponding to the at least one cell, a key corresponding to the at least one cell, an NCC corresponding to the at least one cell, and an unused NCC; A transceiver unit is used to send the first identifier to the terminal device and the second network device.

31. The device according to claim 30, characterized in that The first identifier is carried in at least one of the following messages: Access layer security mode command message, RRC connection establishment message.

32. The device according to claim 30 or 31, characterized in that The transceiver unit is further configured to: Auxiliary information corresponding to at least one network device is sent to the terminal device, where the at least one network device supports a store and forward function and / or the at least one network device has the first context.

33. The device according to any one of claims 30 to 32, characterized in that The transceiver unit is further configured to: Send the first context and the first identifier to the second network device and the core network.

34. A communication device, characterized in that: include: A processing unit, configured to obtain a first identifier, where the first identifier is used to identify a first context of a terminal device associated with a first network device; a transceiver unit, configured to receive a paging message or a PDCCH command from a second network device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier; The processing unit is further configured to: answer the paging message according to the first identifier; or decode the PDCCH command according to the first identifier.

35. A communication device, characterized in that: include: a transceiver unit, configured to receive a first identifier from a first network device, where the first identifier is used to identify a first context of a terminal device associated with the first network device; The transceiver unit is further configured to: when the second network device covers the terminal device, send a paging message or a PDCCH command to the terminal device, wherein the paging message includes the first identifier, or the PDCCH command is scrambled by the first identifier.

36. A communication device, characterized in that include: a processing unit, configured to determine a first identifier for identifying a first context of a terminal device associated with a first network device; The transceiver unit is used to send the first identifier to the terminal device and the second network device, and the first network device and / or the second network device support a store and forward function.

37. A communication device, characterized in that: The device comprises one or more processors configured to execute computer programs or instructions stored in a memory, so that the device performs the method according to any one of claims 1 to 18.

38. A chip or a chip system, characterized in that: The system comprises a processor coupled to a memory, the memory being used to store a computer program, and the processor being used to execute the computer program stored in the memory to implement the method according to any one of claims 1 to 18.

39. A computer-readable storage medium, characterized in that The storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 18 is implemented.

40. A computer program product, characterized in that The invention comprises a computer program which, when being executed, implements the method according to any one of claims 1 to 18.

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