Communication method and communication apparatus

Abstract

A communication method and a communication apparatus, which can be applied to the technical field of satellite communications. The method comprises: when a terminal device leaves the coverage range of a first network device that provides a service for the terminal device, the terminal device changes from a connected state to a first state. When the terminal device is within the coverage range of a second network device, the terminal device sends to the second network device a first request message for requesting to access the second network device. The first state comprises any one of a suspended connected state of an access stratum of the terminal device, a suspended idle state, or an inactive state. Hence, when the terminal device leaves the coverage range of the first network device, the terminal device enters the first state, and the terminal device can still retain context information of the terminal device in the first state, so that the terminal device can correctly access the second network device and normal communication between the terminal device and a network is ensured.

Description

Communication methods and communication devices

[0001] This application claims priority to Chinese Patent Application No. 202410365453.8, filed on March 27, 2024, entitled "Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and more specifically, to a communication method and a communication device. Background Technology

[0003] With the development of communication technology, the fifth-generation mobile network (5G) has introduced satellite communication. Satellite communication can provide communication services to areas that are difficult for terrestrial networks to cover, such as oceans and forests, enhancing the reliability of 5G communication. However, due to the mobility of satellites, their coverage area changes over time. For example, due to satellite mobility, during a certain period, a terminal device may leave the coverage area of ​​the satellite providing its service; that is, the satellite cannot provide service to the terminal device during that time. In this case, the terminal device needs to connect to a new satellite to ensure normal communication between the terminal device and the network.

[0004] To ensure the security of information transmission between terminal devices and satellites, information transmitted between them is often encrypted. In current research scenarios, satellite coverage of terminal devices is discontinuous, while coverage of ground gateway stations is continuous. This means the satellite can connect to the core network equipment in real time through the ground gateway station to obtain relevant information from the terminal devices, ensuring key consistency and normal communication between them. However, in store-and-forward (S&F) scenarios, satellite coverage is discontinuous relative to both ground gateway stations and terminal devices. The satellite cannot simultaneously cover both. Each time a terminal device connects to a new satellite, it re-derives the key, leading to misalignment of transmission keys and hindering normal communication. Therefore, ensuring normal communication between terminal devices and the network in S&F scenarios is a current research focus. Summary of the Invention

[0005] This application provides a communication method and a communication device that can ensure normal communication between terminal devices and the network in S&F scenarios.

[0006] Firstly, a communication method is provided, which can be executed by a terminal device, or by a component of the terminal device (such as a chip or circuit), and this application does not limit this. The following description uses a terminal device as an example.

[0007] The method includes: when a terminal device leaves the coverage area of ​​a first network device providing services to the terminal device, the terminal device changes from a connected state to a first state, the first state including any one of the following: a suspended connected state of the access layer AS of the terminal device, a suspended idle state, or an inactive state; the terminal device sends a first request message to a second network device, the first request message being used to request access to the second network device, the first request message including the identification information of the terminal device, wherein the first network device and the second network device are non-terrestrial network devices.

[0008] It should be understood that the first network device and the second network device may be the same or different network devices.

[0009] [Corrected according to Rule 91, March 2025] It should be understood that the suspended connection state of the access stratum (AS) of a terminal device is a special connection state. In this suspended connection state, the terminal device still retains its context information. This suspended connection state can be understood as the terminal device remaining in the connected state while ceasing AS-level processing operations. For example, the terminal device stops detecting radio link failures (RLFs), stops measurement, stops monitoring paging, etc.

[0010] It should be understood that the suspended idle state is a special type of idle state. In the suspended idle state, the terminal device retains the terminal device's context information but does not release it.

[0011] It should be understood that the first network device and the second network device are non-terrestrial network devices. The first network device and the second network device can be satellites, drones, etc., and this application does not limit them.

[0012] It should be understood that the premise for the terminal device to send the first request information to the second network device is that the terminal device is within the coverage area of ​​the second network device, or in other words, the second network device has moved to an area that can cover the terminal device.

[0013] According to the method provided in this application, when a terminal device leaves the coverage area of ​​a first network device, that is, when the source network device (e.g., the first network device) that provides services to the terminal device no longer provides services to the terminal device, the terminal device changes from a connected state to a first state. In the first state, the terminal device retains its context information, which facilitates correct access to a new target network device that provides services to the terminal device (e.g., the second network device), and ensures normal communication between the terminal device and the network.

[0014] In conjunction with the first aspect, in some possible implementations, the terminal device receives first information from a first network device, the first information including at least one third network device, the at least one third network device including a second network device and / or the first network device, and each of the at least one third network device being a non-terrestrial network device.

[0015] It should be understood that the first network device instructs at least one third network device to the terminal device via first information. The at least one third network device can be understood as a network device that subsequently provides services to the terminal device, or it can also be understood as a potential network device that the terminal device can access (or is allowed to access) subsequently.

[0016] It should also be understood that, if at least one third network device included in the first information is the first network device, the aforementioned terminal device sends a first request to a second network device, wherein the second network device is the same network device as the first network device. Based on the first information, the terminal device requests access to the first network device.

[0017] It should also be understood that, in cases where the first information includes at least one third network device, which includes both the first network device and the second network device, the terminal device sends a first request to the second network device, which is a different network device from the first network device. The terminal device selects the second network device from the first and second network devices to request access.

[0018] In conjunction with the first aspect, in some possible implementations, before the terminal device sends the first request information to the second network device, the method further includes: the terminal device receiving first indication information from the first network device, the first indication information being used to indicate that when the terminal device leaves the coverage area of ​​the first network device and then re-enters the coverage area of ​​the first network device, the terminal device accesses the first network device, wherein the first network device and the second network device are the same network device (or the first network device and the second network device are identical).

[0019] In one possible implementation, the first instruction information is used to instruct the terminal device to access the first network device and to prohibit access to network devices other than the first network device.

[0020] It should be understood that if a terminal device leaves the coverage area of ​​the first network device, according to the first instruction information, the terminal device needs to wait until it re-enters the coverage area of ​​the first network device before it can connect to the first network device. The terminal device cannot connect to any other network device besides the first network device.

[0021] In conjunction with the first aspect, in some possible implementations, the terminal device sends a first request message to the second network device, including: the terminal device receiving indication information from at least one third network device for indicating the available area of ​​each of the at least one third network device; and the terminal device determining, based on the first information and the indication information for indicating the available area of ​​each of the at least one third network device, to send the first request message to the second network device.

[0022] In conjunction with the first aspect, in some possible implementations, the first information further includes indication information for indicating the available area of ​​each of the at least one third network device, and the terminal device sending the first request information to the second network device includes: the terminal device determining, based on the first information, to send the first request information to the second network device.

[0023] It should be understood that, in cases where at least one third network device includes the first network device, the first information includes indication information for indicating the available area of ​​the first network device.

[0024] The above technical solution allows the terminal device to select a second network device from at least one third network device for access through the available area of ​​each of the at least one third network device, enabling the terminal device to reasonably select a new network device for access and ensuring the communication quality of the terminal device.

[0025] In conjunction with the first aspect, in some possible implementations, at least one third network device includes the first network device, and the first information further includes indication information for indicating the available area of ​​the first network device. Based on the first information, determining to send a first request information to the second network device includes: determining to send the first request information to the second network device when the terminal device is not located within the available area of ​​the first network device.

[0026] It should be understood that the first information includes at least one third network device, which in turn includes the first network device and indication information of the available area of ​​the first network device. When the terminal device is not located within the available area of ​​the first network device, the terminal device may send a first request message to other network devices (e.g., a second network device). The terminal device may be located within the coverage area of ​​the second network device, which may be a network device among at least one third network device, or it may not be a network device among at least one third network device; this application does not limit the specific choice of the second network device.

[0027] In conjunction with the first aspect, in some possible implementations, the terminal device sends the first request information to the second network device, including: sending the first request information to the second network device when a first condition is met, the first condition including: the second network device is the network device with the lowest latency among the at least one third network device, and / or, the second network device has the context information of the terminal device.

[0028] In the above technical solution, the terminal device selects a network device (e.g., a second network device) that meets the first condition from the at least one third network device to access the network, thereby enabling the terminal device to reasonably select a new network device to prepare for access and ensuring the communication quality of the terminal device.

[0029] In conjunction with the first aspect, in some possible implementations, the first information may also include one or more of the following: ephemeris information of each of the at least one third network device, location information of each of the at least one third network device connected to the gateway station, time information of each of the at least one third network device connected to the gateway station, or, whether each of the at least one third network device has context information of a terminal device.

[0030] In conjunction with the first aspect, in some possible implementations, the identification information of the terminal device includes: the cell radio network temporary identifier (C-RNTI) of the terminal device in the first cell, wherein the first cell is the cell within the coverage area of ​​the first network device that provides services to the terminal device; the identification information of the terminal device also includes one or more of the following: the physical cell ID (PCI) of the first cell, the location information of the terminal device, the identification information of the first network device, or the identification information of the first cell.

[0031] In conjunction with the first aspect, in some possible implementations, the method further includes: the terminal device receiving first response information from the second network device, the first response information being used to respond to the first request information, the first response information including a next hop chaining count (NCC); the terminal device communicating with the second network device based on a key determined according to the NCC.

[0032] In the above technical solution, the terminal device determines the key based on the NCC in the first response information and uses the key to conduct encrypted communication with the second network device, thereby ensuring secure communication between the terminal device and the second network device.

[0033] In conjunction with the first aspect, in some possible implementations, before the terminal device sends the first request information to the second network device, the method further includes: the terminal device sending the first request information to at least one third network device other than the second network device; and in the event that the terminal device fails to access the network other than the second network device among the at least one third network device, the terminal device sending the first request information to the second network device.

[0034] In the above technical solution, if any one of the at least three third network devices the terminal device is trying to access fails, the terminal device remains in the first state, preserving its context. The terminal device further sends a first request message to the other network devices (excluding the one mentioned in the first message) to request access, thereby ensuring that the terminal device can successfully select a network device for access and guaranteeing normal communication between the terminal device and the network.

[0035] Secondly, a communication method is provided, which can be executed by a first network device, or by a component of the first network device (such as a chip or circuit), and this application does not limit this. The following description uses a first network device as an example.

[0036] The method includes: a first network device sending first indication information to a terminal device, the first indication information indicating that when the terminal device leaves the coverage area of ​​the first network device and then re-enters the coverage area of ​​the first network device, the terminal device accesses the first network device; the first network device receiving first request information from the terminal device, the first request information requesting access to the first network device, wherein the first network device is a non-terrestrial network device.

[0037] According to the method provided in this application, the first network device instructs the terminal device through first instruction information that if the terminal device leaves the coverage area of ​​the first network device, the terminal device needs to wait until it re-enters the coverage area of ​​the first network device before it can access the first network device.

[0038] Thirdly, a communication method is provided, which can be executed by a first network device, or by a component of the first network device (such as a chip or circuit), and this application does not limit this. The following description uses a first network device as an example.

[0039] The method includes: a first network device sending first information to a terminal device, the first information including at least one third network device and indication information of the available area of ​​each of the at least one third network device, the at least one third network device including a second network device and / or the first network device, and each of the at least one third network device being a non-terrestrial network device.

[0040] Fourthly, a communication method is provided, which can be executed by a first network device, or by a component of the first network device (e.g., a chip or circuit), and this application does not limit this. The following description uses a first network device as an example.

[0041] The method includes: a first network device sending first information to a terminal device, the first information including at least one third network device, the at least one third network device including the first network device and a second network device, the first information further including indication information for indicating the available area of ​​the first network device, each of the at least one third network device being a non-terrestrial network device.

[0042] Fifthly, a method for communication is provided, which can be executed by a first network device, or by a component of the first network device (e.g., a chip or circuit), and this application does not limit this. The following description uses a first network device as an example.

[0043] The method includes: a first network device sending first information to a terminal device, the first information including at least one third network device; the first network device sending second information to a core network device, the second information including first context information of the terminal device, the first context information of the terminal device including identification information of the terminal device, wherein the first network device and at least one third network device are non-terrestrial network devices. If the first network device has an unused next hop (HH), the first context information of the terminal device further includes: a key and a next hop chain to calculate the NCC, the key being determined by the first network device based on the NH; or, if the first network device does not have an unused NH, the first context information of the terminal device further includes: second indication information, the second indication information being used to instruct the core network device to determine the NH and the NCC.

[0044] Wherein, the first network device having unused NH can be understood as: the information stored locally by the first network device includes unused NH; similarly, the first network device not having unused NH can be understood as: the information stored locally by the first network device does not include unused NH.

[0045] In one possible implementation, the second indication information is an explicit cell or message, for example: the second indication information indicates that the first network device does not have an unused NH.

[0046] In another possible implementation, the second indication information is that the first network device does not carry the key and / or NCC in the first context message, and the second indication information implicitly instructs the core network device to determine the NH and NCC.

[0047] In conjunction with the fifth aspect, in some possible implementations, before the first network device sends the second information to the core network device, the method further includes: the first network device receiving second request information from the core network device, the second request information requesting to obtain first context information of the terminal device, the second request information including the identification information of the terminal device.

[0048] In conjunction with the fifth aspect, in some possible implementation methods, the identification information of the terminal device includes: the temporary cell radio network identifier (C-RNTI) of the terminal device in the first cell, wherein the first cell is a cell within the coverage area of ​​the first network device that provides services to the terminal device; the identification information of the terminal device also includes one or more of the following: the physical cell identifier (PCI) of the first cell, the location information of the terminal device, the identification information of the first network device, or the identification information of the first cell.

[0049] In conjunction with the fifth aspect, in some possible implementations, the first information may also include one or more of the following: ephemeris information of each of the at least one third network device, location information of each of the at least one third network device connected to the gateway station, time information of each of the at least one third network device connected to the gateway station, or, whether each of the at least one third network device has context information of the terminal device.

[0050] In conjunction with the fifth aspect, in some possible implementations, the second information also includes: identification information of each third network device in at least one third network device.

[0051] Sixthly, a method for communication is provided, which can be executed by a core network device, or by a component of the core network device (e.g., a chip or circuit), and this application does not limit this. The following description uses a core network device as an example.

[0052] The method includes: a core network device receiving second information from a first network device, the second information including first context information of a terminal device, the first context information of the terminal device including identification information of the terminal device; the core network device sending the second context information of the terminal device to at least one third network device, the second context information of the terminal device including a key and an NCC, or the second context information of the terminal device including an NCC and a next-hop NH, wherein the first network device and at least one third network device are non-terrestrial network devices.

[0053] It should be understood that the key included in the second context information of the terminal device is from the first context information of the terminal device, which is determined by the first network device based on its unused NH.

[0054] It should be understood that the sixth aspect corresponds to some of the implementation methods in the first to fifth aspects mentioned above. The technical effects and related introductions can be found in the detailed introductions in the first to fifth aspects mentioned above, and will not be repeated here.

[0055] In conjunction with the sixth aspect, in some possible implementations, where the first network device has an unused NH, the first context information of the terminal device also includes: a key and an NCC.

[0056] In conjunction with the sixth aspect, in some possible implementations, if the first network device does not have an unused NH, the first context information of the terminal device further includes: second indication information, which is used to instruct the core network device to determine the NH and NCC; or, if the first context information of the terminal device does not include the second indication information, the key, and the NCC, the core network device determines the NH and NCC.

[0057] In conjunction with the sixth aspect, in some possible implementations, the core network device sends the second context information of the terminal device to at least one third network device, including: the core network device receiving third request information from the second network device among the at least one third network device, the third request information requesting to obtain the second context information of the terminal device, the third request information including the identification information of the terminal device; and the core network device sending the second context information of the terminal device to the second network device.

[0058] In conjunction with the sixth aspect, in some possible implementations, the method further includes: the core network device receiving third indication information from the second network device among at least one third network device, the third indication information being used to indicate that the terminal device has successfully accessed the second network device; the core network device sending release indication information to other network devices among at least one third network device besides the second network device according to the third indication information, the release indication information being used to indicate the release of the second context information of the terminal device.

[0059] In the above technical solution, when a terminal device accesses a new network device (e.g., a second network device), the second network device sends a third indication message to the core network device to indicate that the terminal device has successfully accessed the second network device. The core network device then sends a release indication message to the other network devices mentioned in the first message to indicate the release of the terminal device's context information, thereby saving resource overhead for other network devices.

[0060] In a seventh aspect, a method for communication is provided, which can be executed by a second network device, or by a component of the second network device (e.g., a chip or circuit), and this application does not limit this. The following description uses a second network device as an example.

[0061] The method includes: a second network device receiving second context information from a terminal device from a core network device; the second network device receiving first request information from the terminal device, the first request information being used to request access to the second network device, the first request information including identification information of the terminal device, wherein the second network device is a non-terrestrial network device.

[0062] It should be understood that the seventh aspect corresponds to some of the implementation methods in the first to sixth aspects mentioned above. The technical effects and related introductions can be found in the detailed introductions in the first to sixth aspects mentioned above, and will not be repeated here.

[0063] In conjunction with the seventh aspect, in some possible implementations, the second network device sends a first response message to the terminal device based on the second context information and the first request information of the terminal device. The first response message includes NCC.

[0064] In conjunction with the seventh aspect, in some possible implementations, before the second network device receives the second context information of the terminal device from the core network device, the method further includes: the second network device receiving the first request information from the terminal device; the second network device sending the second request information to the core network device according to the first request information, the second request information being used to request the acquisition of the second context information of the terminal device, the second request information including the identification information of the terminal device.

[0065] In conjunction with the seventh aspect, in some possible implementations, the NCC in the second context information of the terminal device comes from the first context information of the terminal device, or the NCC is determined by the core network device, wherein the first context information of the terminal device comes from the first network device, which is a network device that provides services to the terminal device before the second network device receives the first request information from the terminal device, and the first network device is a non-terrestrial network device.

[0066] In conjunction with the seventh aspect, in some possible implementations, where the first context information of the terminal device does not include NCC, the first context information of the terminal device includes second indication information, which is used to instruct the core network device to configure NCC and next-hop NH for the terminal device.

[0067] In conjunction with the seventh aspect, in some possible implementation methods, when the terminal device successfully accesses the second network device, the method further includes: the second network device sending third indication information to the core network device, the third indication information being used to indicate that the terminal device has successfully accessed the second network device, the third indication information including the identification information of the terminal device.

[0068] In conjunction with the seventh aspect, in some possible implementations, the method further includes: the second network device sending indication information for indicating the available area of ​​the second network device.

[0069] In conjunction with the seventh aspect, in some possible implementations, the identification information of the terminal device includes: the temporary cell radio network identifier (C-RNTI) of the terminal device in the first cell, wherein the first cell is a cell within the coverage area of ​​the first network device that provides services to the terminal device; the identification information of the terminal device also includes one or more of the following: the physical cell identifier (PCI) of the first cell, the location information of the terminal device, the identification information of the first network device, or the identification information of the first cell.

[0070] In conjunction with the seventh aspect, in some possible implementations, the first request information is a radio resource control (RRC) re-establishment request information or an RRC connection restoration request information; when the first request information is an RRC re-establishment request information, the first request information includes the reason for RRC re-establishment; when the first request information is an RRC connection restoration request information, the first request information includes the reason for RRC connection restoration.

[0071] In conjunction with the seventh aspect, in some possible implementations, when the first request information includes an RRC re-establishment reason, the first request information includes a first reason value, and the first reason value is otherfailure; when the first request information includes an RRC connection restoration reason, the first request information includes a second reason value, and the second reason value is delayTolerantAccess-v1020.

[0072] Eighthly, a communication method is provided, the method comprising: a second network device sending a first message, the first message including a first information element, the first information element being used to indicate whether a first type of terminal device is allowed to access the second network device, the first type of terminal device including a store-and-forward terminal device; the second network device receiving first request information from a terminal device, the first request information being used to request access to the second network device, the terminal device being the first type of terminal device, wherein the second network device is a non-terrestrial network device.

[0073] It should be understood that this method is described executively with the second network device as the execution subject. Of course, the method provided in this application is also applicable to other network devices in at least one third network device (e.g., the third network device itself).

[0074] It should also be understood that the first information element can be called an sfBarred information element. The first message can be a system message, for example, the first message can be a master information block (MIB) or a system information block (SIB), etc., and this application does not limit it.

[0075] It should also be understood that the first type of terminal equipment includes store-and-forward terminal equipment, or terminal equipment that supports S&F functions, or terminal equipment that has the ability to access S&F network equipment.

[0076] It should also be understood that whether the second network device operates in S&F mode can change.

[0077] In one possible implementation, when the second network device is in S&F mode (or when the second network device operates in S&F mode, or when the second network device is an S&F network device), the first information cell is used to indicate that the first type of terminal device is allowed to access the second network device. Therefore, the second network device indicates the access of terminal devices supporting S&F functionality through the first information cell in the first message, thereby ensuring that terminal devices supporting S&F functionality can access the S&F network device.

[0078] In another possible implementation, when the second network device is in non-S&F mode (or when the second network device operates in non-S&F mode, or when the second network device is a non-S&F network device), the first information cell is used to indicate that the first type of terminal device is not allowed / denied from accessing the second network device. The second network device uses the first information cell in the first message to indicate the denial of access by terminal devices supporting S&F functionality, thereby preventing S&F-enabled terminal devices from requesting access to the second network device and saving resource overhead on the terminal devices.

[0079] In conjunction with the eighth aspect, in some possible implementations, in S&F mode, the first information element is a first value, which is used to indicate that the first type of terminal device is allowed to access the second network device.

[0080] As an example, the first value can be "not barred". When the first information cell (sfBarred information cell) is "not barred", the sfBarred information cell is used to indicate that the first type of terminal device is allowed to access the second network device.

[0081] In conjunction with the eighth aspect, in some possible implementations, when the second network device is in non-S&F mode, the first information element is a non-first value, and the first information element is used to indicate that the first type of terminal device is denied access to the second network device.

[0082] As an example, the non-first value can be "barred". When the first information cell (sfBarred information cell) is "barred", the sfBarred information cell is used to indicate that the first type of terminal device is denied access to the second network device.

[0083] It should be understood that the specific values ​​of the first value and non-first value mentioned above are merely examples. The first value and non-first value can also be indicated by one or more combinations of other symbols, numbers, or letters, and this application does not limit them. For example, whether the second network device allows the first type of terminal device to access can be indicated by bit value or binary method, which will not be elaborated on in this application.

[0084] In conjunction with the eighth aspect, in some possible implementations, the first message further includes a second information element and / or a third information element, wherein the second information element is used to indicate whether a second type of terminal device is allowed to access the second network device, and the third information element is used to indicate whether a third type of terminal device is allowed to access the second network device, wherein the second type of terminal device includes terrestrial network terminal devices, and the third type of terminal device includes non-terrestrial network terminal devices.

[0085] It should be understood that terrestrial network terminal equipment is also called normal terminal equipment. Non-terrestrial network terminal equipment is also called NTN terminal equipment, or terminal equipment that supports NTN services, or terminal equipment capable of receiving NTN services.

[0086] It should also be understood that the second information element can be the cellBarred information element in the system message, and the third information element can be the cellBarredNTN information element in the system message; this application does not limit this.

[0087] In conjunction with aspect eight, in some possible implementations, in S&F mode, the second information element is a second value, used to indicate that access to the second type of terminal device is denied; the third information element is a third value, used to indicate that access to the second network device is denied to the third type of terminal device.

[0088] It should be understood that the specific forms of the second and third values ​​are similar to those of the first value mentioned above, and this application does not limit them. For example, the second value can be "barred" and the third value can be "barred".

[0089] Based on the above scheme, in S&F mode, the second and third information elements in the first message of the second network device are used to indicate that the second type of terminal device and the third type of terminal device should refuse to access the second network device, thereby preventing non-S&F terminal devices from accessing the second network device and ensuring that the S&F network device only provides services to terminal devices that support S&F functions.

[0090] In conjunction with aspect eight, in some possible implementations, in non-S&F mode, the second information element is a second value, which is used to indicate that access to the second type of terminal device is denied; the third information element is a non-third value, which is used to indicate that access to the second type of terminal device is allowed.

[0091] It should be understood that non-third values ​​are different from third values, and this application does not limit the specific form of non-third values. For example, a non-second value can be "not barred", and a non-third value can be "not barred".

[0092] [Correction 12.03.2025 based on Rule 91] It should be understood that the second network device is a non-terrestrial network device, that is, the second cell of the second network device is the second value in non-S&F mode or in S&F mode.

[0093] Based on the above scheme, in non-S&F mode, the first information element in the first message of the second network device is used to indicate that access by first-type terminal devices is denied, the second information element is used to indicate that access by second-type terminal devices is denied, and the third information element is used to indicate that access by third-type terminal devices is permitted. When the second network device is not in S&F mode, non-terrestrial network terminal devices are permitted to access the second network device, while terminal devices supporting S&F functionality are denied access, ensuring that terminal devices supporting S&F functionality only access network devices operating in S&F mode.

[0094] A ninth aspect provides a communication method, the method comprising: a terminal device receiving a first message, the first message including a first information element, the first information element being used to indicate whether a first type of terminal device is allowed to access a second network device, the first type of terminal device including a store-and-forward terminal device; when the first information element indicates that the first type of terminal device is allowed to access the second network device, and the terminal device is a first type of terminal device, the terminal device sending first request information to the second network device, the first request information being used to request access to the second network device, wherein the second network device is a non-terrestrial network device.

[0095] It should be understood that the relevant descriptions and technical effects of the ninth aspect are similar to those of the eighth aspect above, and will not be repeated here.

[0096] In conjunction with the ninth aspect, in some possible implementations, in S&F mode, the first information element is a first value, which is used to indicate that the first type of terminal device is allowed to access the second network device.

[0097] In conjunction with the ninth aspect, in some possible implementations, when the second network device is in non-S&F mode, the first information element is a non-first value, and the first information element is used to indicate that the first type of terminal device is denied access to the second network device.

[0098] In conjunction with the ninth aspect, in some possible implementations, the first message further includes a second information element and / or a third information element, wherein the second information element is used to indicate whether a second type of terminal device is allowed to access the second network device, and the third information element is used to indicate whether a third type of terminal device is allowed to access the second network device, wherein the second type of terminal device includes terrestrial network terminal devices, and the third type of terminal device includes non-terrestrial network terminal devices.

[0099] In conjunction with aspect nine, in some possible implementations, the first message further includes the second information element and the third information element. If the terminal device is not the first type of terminal device but is the third type of terminal device, the terminal device ignores the first and second information elements, and the terminal device determines whether to send the first request information to the second network device based on the third information element. Alternatively, if the terminal device is not the first type of terminal device but is the second type of terminal device, the terminal device ignores the first and third information elements, and the terminal device determines whether to send the first request information to the second network device based on the second information element.

[0100] In conjunction with the ninth aspect, in some possible implementations, in S&F mode, the second information element is a second value, which is used to indicate that the second type of terminal device is denied access to the second network device; the third information element is a third value, which is used to indicate that the third type of terminal device is denied access to the second network device.

[0101] In conjunction with the ninth aspect, in some possible implementations, in non-S&F mode, the second information element is a second value, which is used to indicate that access to the second type of terminal device is denied; the third information element is a non-third value, which is used to indicate that access to the second type of terminal device is allowed.

[0102] In one possible implementation, assuming the terminal device is not a first-type terminal device but a third-type terminal device, the terminal device can ignore the values ​​of the first and second information elements. When the third information element is not a third value, the terminal device determines to send the first request information to the second network device based on the value of the third information element. Alternatively, assuming the terminal device is not a first-type terminal device but a second-type terminal device, the terminal device can ignore the values ​​of the first and third information elements. It should be understood that if the second network device is a non-terrestrial network device, the second information element is a second value, and the terminal device determines not to send the first request information to the second network device.

[0103] A tenth aspect provides a communication device comprising a transceiver unit and a processing unit. When a terminal device leaves the coverage area of ​​a first network device providing services to the terminal device, the processing unit is configured to change the state of the communication device from a connected state to a first state, the first state including any one of the following: a suspended connected state of the terminal device's access layer AS, a suspended idle state, or an inactive state; the transceiver unit is configured to send first request information to a second network device, the first request information being used to request access to the second network device, the first request information including identification information of the terminal device, wherein the first network device and the second network device are non-terrestrial network devices.

[0104] It should be understood that the transceiver unit is also used to perform the receiving and transmitting processes as described in the first aspect above. This processing unit can perform other processes described in the first aspect besides receiving and transmitting.

[0105] Eleventhly, a communication device is provided, comprising a transceiver unit. The transceiver unit is configured to send first indication information to a terminal device, the first indication information indicating that when the terminal device leaves the coverage area of ​​the first network device and then re-enters the coverage area of ​​the first network device, the terminal device shall access the first network device; the transceiver unit is further configured to receive first request information from the terminal device, the first request information requesting access to the first network device, wherein the first network device is a non-terrestrial network device.

[0106] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the second aspect above.

[0107] In a twelfth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to transmit first information to a terminal device, the first information including at least one third network device and indication information of the available area of ​​each of the at least one third network device, wherein the at least one third network device includes a second network device and / or the first network device, and each of the at least one third network device is a non-terrestrial network device.

[0108] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the third aspect above.

[0109] In a thirteenth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to transmit first information to a terminal device, the first information including at least one third network device, the at least one third network device including a first network device and a second network device, the first information further including indication information for indicating an available area of ​​the first network device, each of the at least one third network device being a non-terrestrial network device.

[0110] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the fourth aspect above.

[0111] In a fourteenth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to send first information to a terminal device, the first information including at least one third network device; the transceiver unit is further configured to send second information to a core network device, the second information including first context information of the terminal device, the first context information including identification information of the terminal device, wherein the first network device and the at least one third network device are non-terrestrial network devices. If the first network device has an unused next-hop NH, the first context information of the terminal device further includes: a key and a next-hop chain calculation NCC, the key being determined by the first network device based on the NH; or, if the first network device does not have the unused NH, the first context information of the terminal device further includes: second indication information, the second indication information being used to instruct the core network device to determine the NH and the NCC.

[0112] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the fifth aspect above.

[0113] In one possible implementation, the communication device further includes a processing unit that can perform other processing steps besides receiving and transmitting as described in the fifth aspect above.

[0114] In a fifteenth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to receive second information from a first network device, the second information including first context information of a terminal device, the first context information of the terminal device including identification information of the terminal device; the transceiver unit is further configured to transmit the second context information of the terminal device to at least one third network device, the second context information of the terminal device including a key and the NCC, or the second context information of the terminal device including the NCC and a next-hop NH, wherein the key is determined based on the NH, and the first network device and the at least one third network device are non-terrestrial network devices.

[0115] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the sixth aspect above.

[0116] In one possible implementation, the communication device further includes a processing unit that can perform other processing steps besides receiving and transmitting as described in the sixth aspect above.

[0117] In a sixteenth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to receive second context information from a terminal device of a core network device; the transceiver unit is configured to receive first request information from the terminal device, the first request information being used to request access to a second network device, the first request information including identification information of the terminal device, wherein the second network device is a non-terrestrial network device.

[0118] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the seventh aspect above.

[0119] In one possible implementation, the communication device further includes a processing unit that can perform other processing steps besides receiving and transmitting as described in the seventh aspect above.

[0120] In a seventeenth aspect, a communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to transmit a first message, the first message including a first information cell, the first information cell indicating whether access to a second network device by a first type of terminal device is permitted, the first type of terminal device including a store-and-forward terminal device; the transceiver unit is further configured to receive first request information from a terminal device, the first request information being used to request access to the second network device, the terminal device being the first type of terminal device, wherein the second network device is a non-terrestrial network device.

[0121] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the eighth aspect above.

[0122] In one possible implementation, the communication device further includes a processing unit that can perform other processing steps besides receiving and transmitting as described in the eighth aspect above.

[0123] Eighteenth aspect: A communication apparatus is provided, comprising a transceiver unit. The transceiver unit is configured to receive a first message, the first message including a first information cell, the first information cell indicating whether a first type of terminal device is allowed to access a second network device, the first type of terminal device including a store-and-forward terminal device; the transceiver unit is further configured to send a first request message to the second network device, the first request message requesting access to the second network device, the terminal device being the first type of terminal device, wherein the second network device is a non-terrestrial network device.

[0124] It should be understood that the transceiver unit is also used to perform the receiving and sending processes as described in the ninth aspect above.

[0125] In one possible implementation, the communication device further includes a processing unit that can perform other processing steps besides receiving and transmitting as described in the ninth aspect above.

[0126] In a nineteenth aspect, embodiments of this application provide a communication device. This communication device may be a device or apparatus with a chip, or a device or apparatus with integrated circuitry, or a chip, chip system, module, or control unit within the aforementioned devices or apparatuses; specific details are not limited in this application. It should be noted that in this application, the term "communication device" can refer to the communication device itself, or to a chip, functional module, or integrated circuit within the communication device that performs the methods provided in this application; specific details are not limited in this application. This device is used to execute the methods provided in the first to ninth aspects. Specifically, the device may include units and / or modules for executing the methods provided in any of the implementations of the first to ninth aspects, such as a transceiver unit (or transceiver module) and a processing unit (or processing module).

[0127] In some implementations, the processing unit may be at least one processor. The transceiver unit may be a transceiver, or an input / output interface. Optionally, the transceiver may be transceiver circuitry. Optionally, the input / output interface may be input / output circuitry.

[0128] In some implementations, the communication device is a chip, chip system, or circuit in a terminal device or network device. The transceiver module can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit. The processing unit can be at least one processor, processing circuit, or logic circuit.

[0129] In a twentieth aspect, embodiments of this application provide a processor for executing the methods provided in the foregoing aspects. Unless otherwise specified, or if it does not contradict its actual function or internal logic in the relevant description, the transmission and reception operations involved in the processor can be understood as processor output and reception, input, and other operations, or as transmission and reception operations performed by radio frequency circuits and antennas; this application does not limit these operations.

[0130] In a twentieth aspect, embodiments of this application provide a communication system, which includes a terminal device and a network device. The terminal device can execute the method provided in any one of the implementations of the first and ninth aspects described above; the network device can execute the method provided in any one of the implementations of the second, third, fourth, sixth, and seventh aspects described above.

[0131] In one possible implementation, the communication system further includes a core network device that can perform the methods provided in any of the implementations of the fifth aspect described above.

[0132] In a twenty-second aspect, embodiments of this application provide a computer-readable storage medium. This computer-readable storage medium stores instructions or program code that, when executed by a processor, can implement the method provided in any of the implementations of the first to ninth aspects described above.

[0133] In a twentieth aspect, embodiments of this application provide a computer program product containing instructions. When the computer program product is run on a computer, it causes the computer to perform the method provided in any of the implementations of the first to ninth aspects described above.

[0134] In a twentieth aspect, embodiments of this application provide a chip. The chip includes a processor and a communication interface. The processor reads instructions stored in a memory through the communication interface and executes the method provided in any one of the implementations of the first to ninth aspects described above.

[0135] Optionally, as one implementation, the chip also includes a memory storing computer programs or instructions, and a processor is used to execute the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the processor is used to execute the method provided by any one of the implementations of the first to ninth aspects described above.

[0136] The beneficial effects of the third to sixteenth aspects mentioned above can be found in the descriptions of the beneficial effects in the first or second aspects, and will not be repeated here. Attached Figure Description

[0137] Figure 1 is a schematic diagram of the communication system used in the embodiments of this application.

[0138] Figure 2 is a schematic diagram of the network architecture provided in an embodiment of this application.

[0139] Figure 3 is a schematic diagram of the KeNB update method.

[0140] Figure 4 is a schematic diagram of a S&F scenario.

[0141] Figure 5 is a flowchart illustrating a communication method provided in an embodiment of this application.

[0142] Figure 6 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0143] Figure 7 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0144] Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0145] Figure 9 is a schematic diagram of the communication device provided in an embodiment of this application.

[0146] Figure 10 is another schematic diagram of the communication device provided in the embodiments of this application.

[0147] Figure 11 is a schematic diagram of a chip system provided in an embodiment of this application. Detailed Implementation

[0148] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0149] For ease of understanding, the communication system shown in Figure 1 is used as an example to describe the communication systems applicable to the various embodiments of this application.

[0150] As shown in Figure 1, the communication system includes a radio access network (RAN) 100 and a core network (CN) 200. RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal device (120a-120j in Figure 1, collectively referred to as 120). The RAN may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). Terminal device 120 is wirelessly connected to RAN node 110. RAN node 110 is connected to core network 200 wirelessly or via wired connection. The core network devices in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and radio access network logical functions.

[0151] RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G, and 6G mobile communication systems, non-terrestrial network (NTN) systems, or future-oriented evolution systems. RAN 100 can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system, or a communication system that integrates two or more of the above systems.

[0152] In a communication system, a device can send signals to or receive signals from another device. These signals can include information, signaling, or data. The device can also be replaced by an entity, network entity, communication equipment, communication module, node, or communication node; this application describes the example using a device.

[0153] In this application embodiment, the terminal device is a device with wireless transceiver function, which may refer to user equipment (UE), access terminal, subscriber unit, user station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user device.

[0154] In this application embodiment, the terminal device can also be a satellite phone, cellular phone, smartphone, wireless data card, wireless modem, machine-type communication device, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), customer-premises equipment (CPE), point of sale (POS) machine, handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, vehicle-mounted device, communication device mounted on a high-altitude aircraft, wearable device, drone, robot, terminal in device-to-device (D2D) communication, terminal in vehicle-to-everything (V2X) communication, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, and remote medical... Wireless terminals in medical applications, smart grids, transportation safety, smart cities, smart homes, or communication networks evolving after 5G are not limited to this category. In this embodiment, the device used to implement the functions of the terminal device can be the terminal device itself, or a device capable of supporting the terminal device in implementing those functions, such as a chip system or a chip. This device can be installed in the terminal device. In this embodiment, the chip system can consist of chips or include chips and other discrete components.

[0155] In this embodiment of the application, the terminal device may also be a device with communication function in a 6G communication system, and the form or type of the terminal device in 6G and other future communication systems is not limited.

[0156] In this embodiment, RAN node 110 can also be referred to as access network equipment, access node, or RAN entity, and is used to help terminal equipment achieve wireless access. Multiple RAN nodes 110 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal equipment 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminals 120j accessing RAN 100 through network element 120i, network element 120i is a base station; but for base station 110a, network element 120i is a terminal equipment. RAN node 110 and terminal equipment 120 are sometimes referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal functions.

[0157] In one possible scenario, RAN node 110 can also be a network device, which can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system, etc. RAN nodes can be macro base stations (as shown in Figure 1, 110a), micro base stations or indoor stations (as shown in Figure 1, 110b), relay nodes or donor nodes, or radio controllers in CRAN scenarios. Optionally, RAN nodes can also be servers, wearable devices, vehicles, or in-vehicle equipment, etc. For example, network devices in vehicle-to-everything (V2X) technology can be roadside units (RSUs).

[0158] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, with different RAN nodes implementing some of the base station's functions. For example, RAN nodes can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as the baseband unit (BBU). The CU and DU nodes separate the gNB's protocol layers; some protocol layer functions are centrally controlled by the CU, while the remaining partial or complete protocol layer functions are distributed in the DU, which is centrally controlled by the CU. As one implementation, the CU deploys the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, and Service Data Adaptation Protocol (SDAP) layer in the protocol stack; the DU deploys the Radio Link Control (RLC) layer, Media Access Control (MAC) layer, and Physical Layer (PHY) in the protocol stack. Thus, the CU has the processing capabilities of RRC, PDCP, and SDAP. The DU has the processing capabilities of RLC, MAC, and PHY. It is understood that the above functional division is merely an example and does not constitute a limitation on the CU and DU. The RU can be included in radio frequency equipment or radio frequency units, such as in a remote radio unit (RRU), active antenna unit (AAU), or remote radio head (RRH).

[0159] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0160] Optionally, for network elements in the ORAN system, each network element can implement the protocol layer functions shown in Table 1 below.

[0161] Table 1

[0162] It should be noted that in the ORAN system, the network device in this application can be one or more network elements listed in Table 1 above.

[0163] In this embodiment, core network equipment 200 refers to equipment in the core network (CN) that provides service support for terminal equipment 120. Examples of core network equipment include: access and mobility management function (AMF) entities, session management function (SMF) entities, user plane function (UPF) entities, etc., which are not listed here. The AMF entity is responsible for access management and mobility management of the terminal equipment; the SMF entity is responsible for session management, such as user session establishment; and the UPF entity can be a user plane function entity, primarily responsible for connecting to external networks. It should be noted that in this application, entities can also be referred to as network elements or functional entities. For example, an AMF entity can also be called an AMF network element or an AMF functional entity, and an SMF entity can also be called an SMF network element or an SMF functional entity, etc.

[0164] In this embodiment, the apparatus for implementing the functions of a network device can be a network device itself; it can also be an apparatus capable of supporting the network device in implementing those functions, such as a chip system, hardware circuit, software module, or a hardware circuit plus a software module. This apparatus can be installed in the network device or used in conjunction with the network device. In this embodiment, the example of a network device being used to implement the functions of a network device is provided only and does not constitute a limitation on the solutions described in this embodiment.

[0165] It should be noted that the embodiments of this application do not limit the scenario in which the network device / terminal device is located. In addition, the network device / terminal device can be a hardware device or a software function running on dedicated hardware or general-purpose hardware. For example, it can be an entity that includes dedicated or general-purpose hardware devices and software functions. This application does not limit the specific form of the network device / terminal device.

[0166] The following will provide an exemplary description of the scenario architecture, technical terms, and communication methods involved in the methods of this application.

[0167] First, the architecture applicable to the method provided in this application will be described exemplarily with reference to the architectural diagram shown in Figure 2. Of course, the architecture shown in Figure 2 is merely an example, and those skilled in the art can combine or improve upon the architecture provided in this application, which is also applicable to the method provided in this application.

[0168] Figure 2 is a schematic diagram of the network architecture provided in an embodiment of this application.

[0169] Architecture 1: As shown in Figure 2(1), in the transparent satellite scenario, the satellite's role is: wireless frequency filtering, frequency conversion, and amplification. The transparent satellite acts as an L1 relay, regenerating the physical layer signal without any higher protocol layers. The satellite communicates wirelessly with the ground-based NTN gateway, which is connected to the gNB via a wired connection. In this architecture, the satellite can be understood as a remote radio unit of the ground base station (gNB). The satellite simply provides coverage for the physical signal; the remote radio function requires the gateway and the microwave link between the satellite and the gateway to reach the satellite. During transmission, no protocol layer processing is performed, and no logical interface is established.

[0170] Architecture 2: As shown in Figure 2(2), in the regenerated satellite scenario, the regenerated satellite has the processing function of a base station and can perform related processing operations such as storage and forwarding of forwarded data.

[0171] Architecture 3: As shown in Figure 2(3), in a regenerated satellite scenario with inter-satellite links, satellites connect with other satellites via inter-satellite links. In scenarios where local satellites are not visible to ground gateway stations, local satellites can transmit local satellite data to other satellites via inter-satellite links (ISL), and then forward it to the ground gateway station.

[0172] In this architecture, the satellite acts as a base station, possessing all the protocol layer processing functions of a base station. The satellite transmits data back to the ground gateway station via microwave, and the gateway station connects to the 5G core network via wired connection. In the regenerating satellite scenario, the link between the base station and the gateway station is generally referred to as the satellite radio interface (SRI).

[0173] Architecture 4: As shown in Figure 2 (4), in the scenario of a regenerable satellite with DU processing function of a base station, the satellite acts as a gNB-DU and connects to the ground gNB-CU through a ground gateway station.

[0174] Architecture 5: In satellite scenarios with integrated access and backhaul (IAB) functionality, the satellite acts as an IAB node, similar to Architecture 4. However, the difference is that in Architecture 5, in addition to deploying a DU, a mobile terminal (MT) module is also deployed on the satellite. Backhaul is performed using the air interface between the MT and the ground base station, eliminating the need to establish a separate microwave backhaul link between the satellite and the gateway station.

[0175] Secondly, a brief introduction to the security mechanisms of the access layer (AS) of terminal devices will be given.

[0176] Data transmission between the UE and gNB requires encryption and integrity protection, and different messages require different keys. For example, the keys required for data transmission between the UE and gNB include Krrcint (for RRC signaling integrity protection), Krrcenc (for RRC signaling encryption), Kupenc (for user plane encryption), and so on. These keys are all derived from KeNB; therefore, the UE and gNB need to align KeNB values ​​to achieve secure data transmission between them. The following will focus on: 1) how KeNB is obtained when the UE initially accesses the network, 2) how KeNB is updated during handover scenarios, and 3) how KeNB is updated during RRC recovery or RRC re-establishment scenarios.

[0177] 1) Obtaining KeNB in ​​the initial access scenario

[0178] During initial access, both the UE and the core network equipment derive a KeNB (Kevicon New Network) based on the root key Kasme. In this embodiment, the core network equipment is described using a mobility management entity (MME) as an example. The Kasme is derived from the previous-level root key, and the root key Kasme used by the UE and MME to derive the KeNB must be the same. For details, please refer to existing technologies; further explanation is omitted here. The UE obtains the KeNB by calculating it itself based on the Kasme. On the base station side, after the UE establishes an RRC connection with the base station, the base station sends an INITIAL UE MESSAGE to the MME. The core network performs user authentication (or authorization). If the core network successfully authenticates the UE, the MME derives the KeNB and informs the base station via an INITIAL CONTEXT SETUP REQUEST message. At this point, both the UE and the base station have obtained the KeNB value. Next, the base station informs the UE of the encryption algorithm through SMC procedures (such as Security Mode Command messages) and establishes a secure connection with the UE.

[0179] It should be understood that, based on the above description, in the initial access process of the UE, before the SMC process, the communication between the UE and the base station is not encrypted, and after the SMC process, the communication between the UE and the base station is encrypted.

[0180] 2) Switching KeNB updates in the scene

[0181] Handover scenarios include: intra-UE handover (the UE's serving cell is updated, but the base station remains unchanged), inter-UE X2 handover, and inter-UE S1 handover. Intra-UE handover refers to a change in the UE's serving cell, for example, the cell providing service to the UE changes from the source serving cell to the target serving cell, and the base station corresponding to both the source and target serving cells is the same. Inter-UE X2 handover refers to a change in the base station providing service to the UE; that is, X2 handover refers to a switch in the interface between two base stations. Inter-UE S1 handover refers to a change in the interface between the base station providing service to the UE and the MME.

[0182] In the scenario of intra-site handover for the UE, the PCI of the target serving cell, the frequency of the target serving cell, and the previous KeNB or NH are used to determine the updated KeNB. For the aforementioned intra-site handover, since the UE's serving cell has changed—that is, the PCI and frequency of the target serving cell are different from those of the source serving cell—the UE needs to use the updated KeNB for secure communication with the target serving cell after handover.

[0183] In both X2 and S1 handover scenarios between UEs, the UE also needs to update its KeNB.

[0184] It should be understood that KeNB updates can be performed in two ways: horizontal derivation and vertical derivation, as shown in Figure 3. The following section uses inter-UE X2 handover and inter-UE S1 handover as examples to illustrate the KeNB update process.

[0185] Figure 3 is a schematic diagram of the KeNB update method, where KeNB* represents the updated KeNB. The calculation of KeNB* requires three input parameters: the PCI of the target serving cell, the frequency of the target serving cell, and the KeNB or NH before the update.

[0186] In the scenario of UE inter-site X2 handover, the source base station determines the PCI and frequency of the target cell selected for the UE, and then determines the third parameter (either the KeNB or NH before the update) based on the following principles to obtain KeNB*. Specifically, the principles for the source base station to determine the third parameter include: if the source base station has unused {NH, NCC} locally, the third parameter used to determine KeNB* is NH, and the process of generating KeNB* in this case is called vertical derivation; if not, the third parameter used to determine KeNB* is the KeNB before the update, and the process of generating KeNB* in this case is called horizontal derivation.

[0187] It should be understood that, based on the above method of determining KeNB*, vertical derivation is generally used because it offers higher security than horizontal derivation. Specifically, when the source base station does not have unused{NH,NCC} locally, the source base station uses horizontal derivation to determine KeNB*.

[0188] It should also be understood that the next hop (NH) can be understood as the starting point value for KeNB* derivation, and the next hop chaining count (NCC) can be understood as NH and the number of the KeNB derived horizontally based on NH, as shown in Figure 3. After the source base station determines KeNB* through vertical or horizontal derivation, it will send KeNB* and the NCC corresponding to the third parameter together in the handover request message to the target base station. Accordingly, the target base station obtains KeNB* from the source base station, and KeNB* is the new key subsequently used by the target base station and the UE. At the same time, the target base station can forward the NCC received from the source base station to the UE, and the UE further determines KeNB* based on the received NCC.

[0189] The UE can deduce the KeNB* from the NCC, PCI, and frequency of the target cell carried in the handover command sent by the target base station to the UE. For example, the UE can determine whether the NCC in the handover command is the same as the NCC currently used by the UE. If they are the same, it means that this deduction is a horizontal derivation. The UE will perform a horizontal derivation (or horizontal deduction) based on the old KeNB, as well as the PCI and frequency of the target cell carried in the handover command, to obtain the KeNB*. If they are different, it means that this is a vertical derivation. The NH is newly specified. The UE will first vertically deduce hop by hop to the NH corresponding to the current NCC (wherein, the NCC corresponding to the NH is not necessarily the UE's current NCC+1, because there are unused {NH, NCC} in the source base station, which may not be the NCC+1 corresponding to the UE. Therefore, it may be necessary to perform multiple hop-by-hop deductions to obtain the NH). Then, the UE obtains the KeNB* based on the NH, as well as the PCI and frequency of the target cell carried in the handover command.

[0190] It should be understood that, based on the above description, both the target base station and the UE obtain KeNB*. After the UE handover, the target base station sends a PATH SWITCH REQUEST message to the core network MME, informing the core network that the UE has handover to the target base station. The MME maintains the NCC number corresponding to this target base station, and then in the PATH SWITCH REQUEST ACK message, increments this NCC by 1 to calculate the new NH, and sends the calculated {NH, NCC} to the target base station as a supplement for subsequent KeNB* determination. After receiving this {NH, NCC}, the target base station stores it locally as unused {NH, NCC} for the next handover, and deletes other unused {NH, NCC}. In other words, for each UE that the target base station accepts after handover, the core network allocates a new {NH, NCC} as unused {NH, NCC} for the target base station to use with the UE in the next handover. This UE does not necessarily have to be the UE that just handed over; any UE can be used, and this application does not impose any restrictions.

[0191] The above describes the key update in X2 handover between UEs. It can be seen that in X2 handover, the source base station is responsible for generating the new KeNB*. However, in S1 handover, since the MME is involved, the new key derivation is not the responsibility of the source base station, but rather the responsibility of the MME and the target base station. For example, the source base station sends a HANDOVER REQUIRED message to the MME, which does not carry any KeNB* or NCC information. The MME will increment the NCC of the target base station maintained at the MME by 1 to obtain a new NH. The MME then sends this {NH, NCC}, along with the target cell's PCI and frequency, to the target base station via a HANDOVER REQUEST message. The target base station determines the KeNB* based on these three parameters from the message sent by the MME. Inter-site S1 handover is similar to inter-site X2 handover. The target base station sends the NCC, the PCI of the target cell, and the frequency of the target cell to the UE through the MME and the source base station via a handover command. The UE determines whether to use horizontal or vertical derivation to determine the KeNB based on the NCC. This is similar to the inter-site X2 handover described above. For details, please refer to the detailed introduction of inter-site X2 handover above.

[0192] It should be understood that after an inter-site S1 handover, the core network does not send {NH,NCC} to the target station as a supplement. In other words, the core network informs the target base station in the HANDOVER REQUEST that the {NH,NCC} is used for this UE handover. However, in the inter-site X2 handover scenario, the core network informs the target base station in the PATH SWITCH REQUEST ACK that the {NH,NCC} is used for subsequent handovers.

[0193] In summary, during X2 handover between stations, KeNB* may be determined by vertical or horizontal derivation; while during S1 handover between stations, KeNB* is determined by vertical derivation.

[0194] 3) KeNB updates during RRC connection reestablishment or RRC connection resume.

[0195] When a connected UE detects a radio link failure with the current base station, it will select a new base station to initiate an RRC Connection Reestablishment procedure. For UEs in RRC idle, RRC connected, or RRC inactive states, KeNB* needs to be updated during RRC re-establishment and RRC connection recovery scenarios. The following describes how KeNB* updates are determined in RRC re-establishment / RRC connection recovery scenarios.

[0196] In both scenarios, the first RRC message transmitted by the UE when accessing a new base station (e.g., RRC connection reestablishment request / RRC connection resume request) is unencrypted. This RRC message carries the value of shortMAC-I. This shortMAC-I is used to verify the legitimacy of the UE. ShortMAC-I is calculated based on the Krrcint key using three input parameters: the UE's identifier C-RNTI in the source cell, the source cell's PCI, and the target cell's cell ID. The shortMAC-I is then truncated (note that these three parameters are different from the three parameters used to calculate KeNB*).

[0197] In the re-establishment scenario, the UE reports its shortMAC-I used under the source base station, as well as its C-RNTI and source cell PCI under the source base station in the RRC connection reestablishment request message. The target base station determines the source base station identifier based on the source cell PCI and puts this information together with the target cell cell ID in the RETRIEVE UE CONTEXT REQUEST message and sends it to the source base station. The source base station verifies whether the ShortMAC-I carried in this RETRIEVE UE CONTEXT REQUEST is consistent with the ShortMAC-I it calculates based on the three parameters of the UE's C-RNTI, source cell PCI, and target cell cell ID. If they are consistent, the UE is confirmed to be legitimate and is a UE that the source cell has previously served. The source base station will send the KeNB* and NCC determined by the source base station to the target base station in the RETRIEVE UE CONTEXT RESPONSE message. Then, the target base station sends the NCC to the UE through the RRC message. The method for the source base station and UE to determine KeNB* is the same as that for the inter-site X2 handover scenario described above. For details, please refer to the detailed introduction in the inter-site X2 handover scenario described above. It will not be repeated here.

[0198] For the re-establishment scenario, the UE carries its own shortMAC-I and resumeIdentity used under the source base station in the RRC connection resume request message. The resumeIdentity includes a field representing the source base station identifier (e.g., resumeIdentity = PLMN ID + gNB ID + UE ID). The target base station determines the source base station identifier based on the resumeIdentity and puts the shortMAC-I, resumeIdentity, and the cell ID of the target cell in the RETRIEVE UE CONTEXT REQUEST message and sends it to the source base station. The source base station determines the specific UE based on the resumeIdentity, then determines the ShortMAC-I based on the C-RNTI of the source cell, the PCI of the source cell, and the cell ID of the target cell. This ShortMAC-I is compared with the ShortMAC-I in the RETRIEVE UE CONTEXT REQUEST message. If the ShortMAC-I determined by the base station matches the ShortMAC-I in the RETRIEVE UE CONTEXT REQUEST message, the UE is confirmed as legitimate, meaning it was previously served by the source cell. The source base station will then send the KeNB* and NCC determined by the source base station to the target base station in the RETRIEVE UE CONTEXT RESPONSE message. The target base station then sends the NCC to the UE via an RRC message. The method by which the source base station and UE determine the KeNB* is the same as that used in the inter-site X2 handover scenario described above; please refer to the detailed explanation in the inter-site X2 handover scenario above for further details. This will not be repeated here.

[0199] Next, we will introduce the store and forward (S&F) scenario as an example.

[0200] Within 3GPP, NTN-related topics include New Radio (NR) NTN and Internet of Things (IoT) NTN. They use essentially the same architecture, with some differences in characteristics. IoT NTN is an evolution of LTE, using eNodeBs (eNBs) as base stations. In Release 19, IoT NTN will study store-and-forward (S&F) technology based on a regenerator satellite architecture. The need for S&F stems from the fact that some smaller satellite companies have a limited number of satellites and ground gateway stations, making it impossible to maintain constant ground gateway station connectivity with satellites.

[0201] Figure 4 illustrates a S&F (Service & Default) scenario. When a satellite covers a UE, the satellite cannot connect to the gateway station and cannot communicate with the core network; when the satellite connects to the gateway station and communicates with the core network, there is no UE within the satellite's coverage area. In this scenario, normal real-time services cannot be completed. However, for some non-real-time IoT services (such as sensor data reporting), communication between the satellite and the UE can be initiated when the satellite covers the UE, and then communication between the satellite and the core network can be initiated when the satellite covers the gateway station, in a relay manner. This is the S&F scenario currently under research. In this S&F scenario, the satellite needs to have certain storage and processing capabilities to cache data arriving from the UE or core network and forward it when it re-covers the core network or UE at a future time. Therefore, the satellite in this S&F scenario is a regenerable satellite, for example, it can act as an eNB (eNB).

[0202] The discontinuous coverage scenarios under IoT NTN studied in Release 18 mainly involve situations where, after one satellite departs, a subsequent satellite will only cover the UE after a certain period. In Release 18, the coverage between the satellite and the ground gateway is continuous; the satellite can always connect to the ground gateway. The satellites in Release 18 are pass-through satellites, unlike the regenerable satellites in the S&F scenario. Therefore, Release 18 does not consider the discontinuous coverage situation between the satellite and the ground gateway.

[0203] In the S&F scenario, the satellite coverage is discontinuous relative to the ground gateway station and the UE. The UE cannot align the KeNB value with the base station, which prevents the establishment of a secure connection between the UE and the base station and prevents normal communication between the UE and the network.

[0204] Based on the above-mentioned technical problems, this application provides a communication method that can ensure normal communication between the UE and the network in S&F scenarios.

[0205] Figure 5 is a flowchart illustrating a communication method provided in an embodiment of this application.

[0206] It should be understood that in the method shown in Figure 5, taking network device 1 as the first network device as an example, network device 1 is a non-terrestrial network device, such as a satellite or a drone, and this application does not limit it.

[0207] As shown in Figure 5(a), the method may include the following steps.

[0208] 501-a, The terminal device receives the first instruction information from network device 1.

[0209] Accordingly, network device 1 sends the first instruction information to the terminal device.

[0210] For example, when a terminal device is within the coverage area of ​​network device 1, and network device 1 provides services to the terminal device, network device 1 sends the first indication information to the terminal device. This first indication information is used to instruct the terminal device to access network device 1 when it leaves and re-enters the coverage area of ​​network device 1, or to instruct the terminal device to access network device 1 and prohibit access to network devices other than network device 1.

[0211] 502-a, the terminal device changes from the connected state to the first state.

[0212] It should be understood that when a terminal device leaves the coverage area of ​​network device 1, the terminal device changes from the connected state to the first state.

[0213] As an example, the terminal device leaves the coverage area of ​​network device 1 at a first moment, which may be indicated to the terminal device by network device 1. This first moment may be determined by network device 1 based on its own movement trajectory and the location information of the terminal device, at which time network device 1 ceases to provide services to the terminal device.

[0214] It should also be understood that the first state includes one or more of the following: a suspended connected state, a suspended idle state, or an inactive state of the access layer AS of the terminal device.

[0215] [Corrected according to Rule 91, March 2025] The suspended connection state of the access layer AS of a terminal device is a special type of connection state. In this suspended connection state, the terminal device still retains its context information. This suspended connection state can be understood as the terminal device remaining in the connected state while ceasing all AS-layer processing operations. For example, the terminal device stops detecting RLF, stops measurement, stops monitoring Paging, etc.

[0216] Among them, the suspended idle state is a special type of idle state. In the suspended idle state, the terminal device retains the context information of the terminal device and does not release the context information of the terminal device.

[0217] Even when the terminal device is inactive, it still monitors the network so that it can be reactivated and communicate with the network when needed.

[0218] It should also be understood that step 502-a is an optional step, and the remaining steps in (a) of Figure 5 may exist independently of step 502-a.

[0219] 503-a, The terminal device sends a first request message to network device 1.

[0220] Accordingly, network device 1 receives the first request information from the terminal device.

[0221] For example, when a terminal device receives a first request message from network device 1, and the terminal device leaves the coverage area of ​​network device 1 and changes from a connected state to a first state, when the terminal device re-enters the coverage area of ​​network device 1, the terminal device sends a first request message to network device 1 to request access to network device 1.

[0222] As shown in Figure 5(b), the method may include the following steps.

[0223] 501-b, The terminal device receives the first information from network device 1.

[0224] Accordingly, network device 1 sends the first information to the terminal device.

[0225] For example, when the terminal device is within the coverage area of ​​network device 1, and network device 1 provides services to the terminal device, network device 1 sends the first information to the terminal device. This first information is used to instruct network device 1.

[0226] Optionally, the first information includes indication information for indicating the available area of ​​network device 1. Optionally, the range of the available area may be smaller than the cell covered by network device 1, or in other words, the available area is a part of the cell provided by network device 1 (e.g., the cell center area).

[0227] 502-b, the terminal device changes from the connected state to the first state.

[0228] It should be understood that when a terminal device leaves the coverage area of ​​network device 1, the terminal device changes from the connected state to the first state.

[0229] It should also be understood that step 502-b is an optional step, and the remaining steps in (b) of Figure 5 may exist independently of step 502-b.

[0230] 503-b, The terminal device sends a first request message to network device 1.

[0231] Accordingly, network device 1 receives the first request information from the terminal device.

[0232] For example, when a terminal device is located in an available area of ​​network device 1, the terminal device sends a first request message to network device 1 based on the first information. The first request message is used to request access to network device 1.

[0233] It should be understood that the terminal device is located in the available area indicated by network device 1, and the example described is the terminal device sending a first request message to network device 1 in step 503-b. Of course, assuming the terminal device is not located in the available area indicated by network device 1, but is within the coverage area of ​​another network device (e.g., network device 2), the terminal device can send a first request message to network device 2, as shown in step 503-b':

[0234] 503-b', The terminal device sends the first request information to network device 2.

[0235] Accordingly, network device 2 receives the first request information from the terminal device.

[0236] The terminal device is located within the coverage area of ​​network device 2.

[0237] It should be understood that, assuming the terminal device is not located in the available area indicated by network device 1, but is located in the coverage area of ​​another network device (e.g., network device 2), the terminal device can send a first request message to network device 2. Specifically, when the terminal device determines, based on the first message, that it is not in the available area indicated by network device 1, it can select another network device covering it to request access. The specific process by which the terminal device selects a network device from those covering it for access is not limited in this application. For example, the terminal device can select any network device covering it to request access.

[0238] It should be understood that in the methods shown in Figure 5(a) and Figure 5(b), network device 1 instructs the terminal device to access network device 1 through first indication information, or network device 1 instructs the terminal device to access network device 1 through first information including only the first network device. Network device 1 possesses the context information of the terminal device, thereby avoiding changes in the serving network device of the terminal device due to the movement of network device 1, and saving the resource overhead of network device 1 in forwarding the context information of the terminal device. Simultaneously, when the terminal device leaves the coverage area of ​​network device 1, the terminal device enters a first state from a connected state. In the first state, the terminal device retains its context information, thereby enabling the terminal device to correctly access the network device subsequently, ensuring secure communication between the terminal device and the network.

[0239] Figure 6 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0240] It should be understood that in the method shown in Figure 6, the first network device is network device 1, and at least one third network device is network device 2 and network device 3, respectively. Network device 2 can be the second network device among the at least one third network device, and network device 3 can be any other network device among the at least one third network device besides the second network device. Network device 1, network device 2, and network device 3 are all non-terrestrial network devices; for example, network device 1, network device 2, and network device 3 can be satellites or drones, and this application does not limit them. As shown in Figure 6, the method may include the following steps.

[0241] 601, Network device 1 sends T_service information to terminal device.

[0242] Accordingly, the terminal device receives T_service information from network device 1.

[0243] It should be understood that network device 1 is the source service network device providing services to the terminal device. Due to the mobility of network device 1, the terminal device may be outside the coverage area of ​​network device 1 at a certain moment, meaning that network device 1 cannot provide services to the terminal device at that moment. The time indicated by the T_service information (e.g., the first moment) is the time when terminal device 1 leaves the coverage area of ​​network device 1. Alternatively, it can be understood that the first moment indicated by the T_service information is the time when network device 1 ceases to provide services to the terminal device, or it can be understood as the deadline for network device 1 to provide services to the terminal device.

[0244] It should also be understood that step 601 is an optional step. Network device 1 may not need to separately indicate the t_service information to the terminal device. When the terminal device determines that it is not within the coverage area of ​​network device 1, or when the terminal device cannot connect to network device 1, the terminal device can update its own status.

[0245] 602, Network device 1 sends the first information to the terminal device.

[0246] Accordingly, the terminal device receives the first information from network device 1.

[0247] It should be understood that the first information includes one or more network devices (e.g., at least one third network device), which is a potential target network device for providing services to the terminal device. For example, the at least one third network device includes network device 2 and network device 3.

[0248] In one possible implementation, the first information includes one or more of the following: ephemeris information of network device 2, ephemeris information of network device 3, time information of network device 2 connecting to the ground gateway station, time information of network device 3 connecting to the ground gateway station, location information of network device 2 connecting to the ground gateway station, or location information of network device 3 connecting to the ground gateway station.

[0249] In another possible implementation, the first information may further include: indication information for indicating the available area of ​​network device 2, and / or, indication information for indicating the available area of ​​network device 3.

[0250] It should be understood that this application does not limit the execution order of steps 602 and 601. For example, step 601 may be executed before step 602, or step 602 may be executed after step 601, or steps 601 and 602 may be executed simultaneously. Where steps 601 and 602 may be executed simultaneously, the T_service information and the first information sent by the network device 1 may be transmitted in the same message or in different messages; this application does not limit this.

[0251] 603, the terminal device changes from connected state to first state.

[0252] For example, when a terminal device receives a T_service message from network device 1, after the time indicated by the T_service message (e.g., the first time) is reached, the terminal device changes from the connected state to the first state; or, when the terminal device determines that it is leaving the coverage area of ​​network device 1, the terminal device changes from the connected state to the first state.

[0253] The first state includes any one of the following: a suspended connection state of the terminal device's access layer, a special idle state (e.g., a suspended idle state), an inactive state, or an idle state.

[0254] [Corrected according to Rule 91, March 2025] It should be understood that when the terminal device is in a connected state with the access layer suspended in the first state, and the terminal device leaves the coverage area of ​​network device 1, the terminal device changes from the connected state to the connected state with the access layer suspended. The terminal device stops access layer operations, for example, the terminal device stops detecting RLF, stops measurement, stops monitoring paging, etc. Optionally, the terminal device can stop all access layer operations. The terminal device retains its context information to facilitate correct access to new network devices later.

[0255] It should be understood that when the first state is a special idle state or inactive state, the special idle state can be a suspended idle state (e.g., IDLE with suspended). When the terminal device changes from the connected state to the suspended idle state or inactive state, the terminal device retains the terminal device's context information to facilitate the correct access to new network devices in the future.

[0256] It should be understood that step 603 refers to the change in the state of the terminal device when the terminal device leaves the coverage area of ​​network device 1, which can be regarded as an internal operation of the terminal device. In the actual implementation process, step 603 may not be reflected in the actual operation.

[0257] 604, Network device 1 sends the second message to the core network device.

[0258] Accordingly, the core network equipment receives the second information from network equipment 1.

[0259] For example, when network device 1 covers a ground gateway station, network device 1 sends second information to the core network device through the ground gateway station. This second information includes first context information of the terminal device, which includes the UE's identification information.

[0260] Optionally, the second information may also include the identification information of network device 2 and the identification information of network device 3.

[0261] In one possible implementation, when the network device 1 has an unused NH, the first context information of the terminal device includes key #1 and NCC. The key #1 is determined by the network device 1 based on the unused NH. The specific determination method is similar to the determination method of KeNB* in the KeNB update in the handover scenario described above (e.g., vertical derivation). Please refer to the detailed description above for details.

[0262] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device includes second indication information, which is used to instruct the core network device to determine the NH and NCC.

[0263] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device does not include key #1, NCC and second indication information.

[0264] 605, the core network device sends the second context information of the terminal device to network device 2 and network device 3.

[0265] Accordingly, network device 2 and network device 3 receive second context information from the terminal device of the core network device.

[0266] For example, the core network device receives first context information from the terminal device in network device 1. Based on the first context information, the core network device sends second context information of the terminal device to network device 2 and network device 3. The second context information of the terminal device includes the terminal device's identification information and NCC, as well as key #1 or NH.

[0267] In one possible implementation, when the terminal device's first context information includes key #1 and NCC, the core network device forwards the terminal device's first context information to network device 2 and network device 3 via the terminal device's second context information. The terminal device's second context information includes key #1 and NCC.

[0268] In another possible implementation, when the first context information of the terminal device includes the second indication information, the core network device generates NH and NCC according to the second indication information, and sends the second context information of the terminal device carrying NH and NCC to network device 2 and network device 3.

[0269] In another possible implementation, when the first context information of the terminal device does not include key #1, NCC, and second indication information, the core network device generates NH and NCC, and sends the second context information of the terminal device carrying NH and NCC to network device 2 and network device 3.

[0270] It should be understood that the core network device sends the second context information of the terminal device to network device 2 and network device 3. The second context information of the terminal device is carried in the same message and sent to network device 2 and network device 3 at the same time, or the second context information of the terminal device is carried in different messages and sent to network device 2 and network device 3 in turn. This application does not limit this.

[0271] It should also be understood that when the core network device sends the second context information of the terminal device to network device 2 and network device 3, the core network device is within the coverage area of ​​network device 2 and network device 3, respectively, and can wirelessly communicate with network device 2 and network device 3. For example, when network device 2 moves to cover a ground gateway station, the core network device sends the second context information of the terminal device to network device 2 through the ground gateway station.

[0272] 606, Network device 2 and Network device 3 send indication information to the terminal device to indicate the available area of ​​Network device 2 and the available area of ​​Network device 3.

[0273] Accordingly, the terminal devices receive indication information from network device 2 and network device 3, respectively, indicating the available areas of their respective network devices.

[0274] It should be understood that, taking network device 2 as an example, network device 2 can broadcast indication information in system messages to indicate the available area of ​​network device 2. When a terminal device enters the coverage area of ​​network device 2, the terminal device can receive the indication information indicating the available area of ​​network device 2. For example, the system message can be a master information block (MIB) or a system information block (SIB).

[0275] It should also be understood that sending indication information indicating the available area of ​​network device 2 and network device 3 to the terminal device is an optional step. If the first information in step 602 includes indication information indicating the available area of ​​network device 2 and network device 3, then step 606 does not need to be executed again.

[0276] 607, The terminal device sends the first request information to network device 2.

[0277] Accordingly, network device 2 receives a first request from the terminal device. This first request includes the terminal device's identification information.

[0278] For example, the terminal device selects network device 2 as the target network device to provide services to the terminal device based on a certain rule or a certain preset condition. This application does not limit the nature of this rule or preset condition; it may be predetermined by the system, pre-configured by the protocol, or determined by the terminal device itself.

[0279] Suppose that the terminal device selects network device 2 as the target network device based on the available areas of multiple network devices (e.g., network device 2, network device 3) and sends a first request message to network device 2 to request access to network device 2.

[0280] Furthermore, suppose that the terminal device determines the transmission delay of network device 2 and network device 3 based on parameters such as the ephemeris information, location information connected to the gateway station, and time information of the network device (e.g., network device 2 and network device 3) indicated in the received first information, selects the network device with the smallest delay (e.g., network device 2) as the target network device, and sends a first request information to network device 2 to request access to network device 2.

[0281] In one possible implementation, the first request information can be an RRC re-establishment request (e.g., an RRC connection re-establishment request) or an RRC connection resumption request. When the first request information is an RRC re-establishment request, it may further include a reason value indicating the re-establishment; this reason value can be "otherfailure," or it can be a reason value related to the terminal device accessing network device 2, and this reason value is related to the S&F scenario. When the first request information is an RRC connection resume request (e.g., an RRC connection resume request), it may further include a reason value indicating the resumption of the resumption; this reason value can be "delayTolerantAccess-v1020," or it can be a reason value related to the terminal device accessing network device 2, and this reason value is related to the S&F scenario. In one implementation, when the first state is a connection state suspended at the access layer, the first request message can be an RRC re-establishment request; when the first state is a special idle state or inactive state, the first request message can be an RRC connection resumption request.

[0282] It should be understood that the identification information of the terminal device includes: the Cell Radio Network Temporary Identifier (C-RNTI) of the terminal device within the first cell, wherein the first cell is a cell within the coverage area of ​​network device 1 that provides services to the terminal device. The first cell may also be referred to as the source serving cell that provides services to the terminal device. Optionally, the identification information of the terminal device may also include one or more of the following: the Physical Cell Identifier (PCI) of the first cell, the location information of the terminal device, the identification information of the first network device, or the identification information of the first cell.

[0283] 608, Network device 2 sends the first response information to the terminal device.

[0284] Accordingly, the terminal device receives the first response information from network device 2.

[0285] For example, after receiving the first request information from the terminal device, network device 2 authenticates (or authorizes) the terminal device based on the terminal device's identification information in the first request information and the terminal device's identification information in the terminal device's second context information received in step 605. If network device 2 successfully authenticates the terminal device and determines it to be a legitimate device, it sends a first response information to the terminal device, which is used to respond to the first request information.

[0286] It should be understood that when network device 2 determines that the terminal device is a legitimate device, network device 2 accepts the access of the terminal device and sends the first response information to the terminal device. The first response information includes NCC. The NCC is the NCC in the second context information of the terminal device received by network device 2 from the core network device. The NCC may come from network device 1 or be determined by the core network device. This application does not limit this.

[0287] It should also be understood that when network device 2 determines that the terminal device is not a legitimate device, it is not necessary to execute step 608 and subsequent steps.

[0288] 609. The terminal device and network device 2 communicate securely.

[0289] It should be understood that after receiving the first response information from network device 2, the terminal device determines the key (e.g., key #1) for secure communication with network device 2 based on the NCC in the first response information. The key #1 determined by network device 2 may be determined by network device 1, or the key #1 determined by network device 2 based on the NH and NCC determined by the core network.

[0290] It should also be understood that the specific methods by which the terminal device determines key #1 based on NCC, and the network device 2 determines key #1 based on NCC, are similar to the method of determining KeNB* in the KeNB update in the above-mentioned 2) handover scenario (e.g., vertical derivation). Please refer to the detailed introduction above for details, which will not be repeated here.

[0291] It should also be understood that the terminal device and network device 2 use key #1 for secure communication.

[0292] 610, Network device 2 sends a third instruction message to the core network device.

[0293] Accordingly, the core network equipment receives the third instruction information from network equipment 2.

[0294] For example, when network device 2 determines that a terminal device has successfully accessed network device 2, network device 2 can send third indication information to the core network device. This third indication information indicates that the terminal device has successfully accessed the second network device. The third indication information includes the terminal device's identification information, such as the UE NGapplication protocol identifier (UE NGAP ID). The third indication information may also include the identification information of network device 3, such as the eNB ID, satellite identifier, or IP address of network device 3. Optionally, if the third indication information includes the identification information of network device 3, the terminal device's identification information can use the identification information of the terminal device under network device 3, such as C-RNTI. This method eliminates the need for the core network device to modify the terminal device's identification; the core network device only needs to obtain the identification information of network device 3 to indicate the terminal device to network device 3 by carrying the terminal device's identification information that network device 3 can recognize.

[0295] 611, the core network device sends a release instruction message to network device 3.

[0296] Accordingly, network device 3 receives release instruction information from the core network device.

[0297] For example, after receiving the third indication information from network device 2, the core network device determines that the terminal device has successfully accessed network device 2 based on the third indication information. The core network device then determines to send release indication information to network device 3. This release indication information is used to indicate the release of the terminal device's second context information. The release indication information includes the terminal device's identification information, such as the terminal device's UE NGAP ID or the terminal device's C-RNTI under network device 3.

[0298] It should also be understood that after receiving the third indication information from network device 2, the core network device can determine at least one third network device based on the identification information of at least one third network device included in the second information in step 604, and send the release indication information to other network devices (e.g., network device 3) among the at least one third network device besides network device 2. Accordingly, after receiving the release indication information from the core network device, network device 3 releases the context information of the terminal device based on the identification information of the terminal device in the release indication information.

[0299] According to the method shown in Figure 6 above, when the terminal device leaves the coverage area of ​​network device 1, that is, when the source network device (e.g., network device 1) that provides services to the terminal device no longer provides services to the terminal device, the terminal device changes from the connected state to the first state. In the first state, the terminal device can retain its context information, which facilitates correct access to a new target network device that provides services to the terminal device (e.g., network device 2). Simultaneously, when network device 1 covers a gateway station, it forwards the terminal device's first context information to the potential target network devices in the first information through the core network device. This facilitates accurate and rapid access when the terminal device subsequently initiates a request to the target network device, ensuring normal communication between the terminal device and the network. Furthermore, when the terminal device accesses a new network device (e.g., network device 2), network device 2 sends a third indication message to the core network device to indicate that the terminal device has successfully accessed network device 2. The core network device then sends a release indication message to the other network devices in the first information to indicate the release of the terminal device's context information, saving resource overhead for other network devices.

[0300] Based on the method shown in Figure 6 above, when the terminal device leaves the coverage area of ​​network device 1, the terminal device changes from the connected state to the first state. This first state may also include an idle state. When the terminal device is in the idle state, it can also release its context information and enter the idle state when leaving the coverage area of ​​network device 1. When a subsequent terminal device enters the coverage area of ​​a network device (e.g., network device 2), the terminal device selects network device 2 to initiate the initial access procedure. Accordingly, the terminal device and network device 2 use a key derived from the root key Kasme for encrypted communication, based on the key acquisition method in the initial access scenario. The key acquisition between the terminal device and network device 2 in the initial access scenario is similar to the acquisition of the KeNB by the terminal device and the base station in scenario 1) above. The terminal device derives the KeNB from the root key Kasme, and the base station receives the KeNB derived from the root key Kasme from the MME. The terminal device and the base station use the KeNB for encrypted communication. For details, please refer to the detailed description above; it will not be repeated here.

[0301] Figure 7 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0302] It should be understood that in the method shown in Figure 7, the first network device is network device 1, and at least one third network device is network device 2 and network device 3, respectively. Network device 2 can be the second network device among the at least one third network device, and network device 3 can be any other network device among the at least one third network device besides the second network device. Network device 1, network device 2, and network device 3 are all non-terrestrial network devices; for example, network device 1, network device 2, and network device 3 can be satellites or drones, and this application does not limit them. As shown in Figure 7, the method may include the following steps.

[0303] 701, Network device 1 sends T_service information to terminal device.

[0304] Accordingly, the terminal device receives T_service information from network device 1.

[0305] 702, Network device 1 sends the first information to the terminal device.

[0306] Accordingly, the terminal device receives the first information from network device 1.

[0307] 703, the terminal device changes from connected state to first state.

[0308] For example, when a terminal device receives a T_service message from network device 1, after the time indicated by the T_service message (e.g., the first time) is reached, the terminal device changes from the connected state to the first state.

[0309] It should be understood that steps 701 to 703 above are similar to steps 601 to 603 in Figure 6 above. For details, please refer to the detailed description of steps 601 to 603 above.

[0310] 704, The terminal device sends the first request information to network device 2.

[0311] Accordingly, network device 2 receives the first request information from the terminal device.

[0312] For example, when network device 2 covers a terminal device, the terminal device sends a first request message to network device 2, which is used to request access to network device 2.

[0313] In one possible implementation, the terminal device can select network device 2 from multiple network devices according to a certain rule or a certain preset condition, and send a first request message to network device 2.

[0314] It should be understood that a certain rule or condition may be predetermined by the system, pre-configured by the protocol, or determined by the terminal device itself; this application does not impose any restrictions on this.

[0315] For example, a terminal device selects a network device based on the availability zones of multiple network devices and sends a first request message to that network device. This indication of the network device's availability zone can be carried in the first message, or in system information broadcast by the network device, etc.

[0316] For example, the terminal device selects the network device with the lowest latency based on the latency of multiple network devices and sends a first request message to that network device. The latency of these multiple network devices can be determined by the terminal device based on information such as ephemeris information, time information, and location information included in the first message.

[0317] For example, the terminal device selects a network device that has the terminal device's context information based on whether each of the multiple network devices has the terminal device's context information, and sends a first request message to that network device. The terminal device can determine which network device to select based on the information in the first message indicating whether each of the multiple network devices has the terminal device's context information.

[0318] It should be understood that the terminal device may select network device 2 based on any of the above examples and send the first request information to network device 2, or select network device 2 based on any two or three of the above examples and send the first request information to network device 2. This application does not limit this.

[0319] It should also be understood that after receiving the first request information from the terminal device, network device 2, assuming it has the context information of the terminal device, further determines whether to accept the access request from the terminal device based on the first request information, as shown in Case 1 below. Alternatively, assuming network device 2 does not have the context information of the terminal device, after receiving the first request information, network device 2 can request the core network device to obtain the context information of the terminal device, as shown in Case 2 below.

[0320] Scenario 1

[0321] 705, Network device 2 sends the first response information to the terminal device.

[0322] Accordingly, the terminal device receives the first response information from network device 2.

[0323] For example, after receiving a first request from a terminal device, network device 2 authenticates the terminal device based on the first request and the local stored context information of the terminal device. If network device 2 successfully authenticates the terminal device, it sends a first response to the terminal device. This first response is used to respond to the first request and includes NCC (Neutral Control Center) information.

[0324] It should be understood that the context information of the terminal device stored in network device 2 may be sent by network device 1 through the core network device, such as step 605 in the method shown in Figure 6 above, where network device 2 receives the second context information of the terminal device sent from the core network device and stores the second context information of the terminal device locally in network device 2. Network device 2 may also obtain the context information of the terminal device through other means, which will not be described in detail in this application.

[0325] 706, Network device 2 communicates securely with terminal devices.

[0326] It should be understood that after the terminal device receives the first response information from the network device 2, the terminal device determines the key (e.g., key #1) for secure communication with the network device 2 based on the NCC in the first response information. The key #1 of the network device 2 may come from the source network device (e.g., network device 1) that provides services to the terminal device, or it may be determined by the network device 2 itself based on the NH and NCC. This application does not limit this.

[0327] It should also be understood that the specific methods by which the terminal device determines key #1 based on NCC and the network device 2 determines key #1 are similar to the methods described above for the terminal device to determine KeNB*. Please refer to the above description for details, which will not be repeated here.

[0328] It should also be understood that the terminal device and network device 2 use key #1 for secure communication.

[0329] 707, Network device 2 sends a third instruction message to the core network device.

[0330] Accordingly, the core network equipment receives the third instruction information from network equipment 2.

[0331] For example, if network device 2 determines that a terminal device has successfully connected to network device 2, network device 2 sends a third indication message to the core network device. This third indication message indicates that the terminal device has successfully connected to the second network device. The third indication message includes the terminal device's identification information.

[0332] 708, the core network device sends a release instruction message to network device 3.

[0333] Accordingly, network device 3 receives release instruction information from the core network device.

[0334] For example, after receiving the third indication information from network device 2, the core network device determines that the terminal device has successfully accessed network device 2 based on the third indication information. The core network device then determines to send a release indication information to network device 3. This release indication information is used to indicate the release of the terminal device's second context information. The release indication information includes the terminal device's identification information.

[0335] It should be understood that the core network device can send the release instruction information to the network device (e.g., network device 3) that has the context information of the terminal device, based on the third instruction information. Steps 707 and 708 are optional steps. When other network devices have not received the context information of the terminal device, and / or have not stored the context information of the terminal device locally on the network device side, that is, steps 707 and 708 do not need to be executed.

[0336] Scenario 2

[0337] At 705', network device 2 sends a second request message to the core network device.

[0338] Accordingly, the core network device receives the second request information from network device 2.

[0339] For example, after receiving the first request information from the terminal device, the network device 2 does not have the context information of the terminal device. The network device 2 sends a second request information to the core network device according to the first request information. The second request information is used to request the acquisition of the context information of the terminal device. The second request information includes the identification information of the terminal device.

[0340] It should be understood that when network device 2 covers a ground gateway station, network device 2 sends the second request information to the core network device through the ground gateway station.

[0341] 706', the core network device sends a third request message to network device 1.

[0342] Accordingly, network device 1 receives a third request from the core network device.

[0343] For example, after the core network device receives the second request information from the network device 2, if the network device 1 covers the ground gateway station, the core network device sends a third request information to the network device 1 through the ground gateway station. The third request information is used to request the acquisition of the context information of the terminal device, and the third request information includes the identification information of the terminal device.

[0344] 707', Network device 1 sends the first context information of the terminal device to the core network device.

[0345] Accordingly, the core network device receives the first context information from the terminal device of network device 1.

[0346] It should be understood that after receiving the third request information from the core network equipment, network device 1 authenticates the terminal device based on the terminal device identification information in the third request information. Upon successful authentication of the terminal device and when network device 1 reaches the ground gateway station, network device 1 sends the terminal device's first context information to the core network equipment through the ground gateway station.

[0347] In one possible implementation, when the network device 1 has an unused NH, the first context information of the terminal device includes key #1 and NCC. The key #1 is determined by the network device 1 based on the unused NH. The specific determination method is similar to the determination method of KeNB* in the KeNB update in the handover scenario described above (e.g., vertical derivation). Please refer to the detailed description above for details.

[0348] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device includes second indication information, which is used to instruct the core network device to determine the NH and NCC.

[0349] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device does not include key #1, NCC, and second indication information.

[0350] It should also be understood that when network device 1 authenticates the terminal device based on the terminal device identification information in the third request information and determines that the terminal device is not a legitimate device, it is not necessary to execute step 707' and subsequent steps.

[0351] 708', the core network device sends the second context information of the terminal device to network device 2.

[0352] Accordingly, network device 2 receives second context information from the terminal device of the core network device.

[0353] For example, the core network device receives the first context information from the terminal device of network device 1, and sends the second context information of the terminal device to network device 2 based on the first context information of the terminal device.

[0354] In one possible implementation, when the first context information of the terminal device includes key #1 and NCC, the core network device forwards the first context information of the terminal device to the network device 2 through the second context information of the terminal device, which includes key #1 and NCC.

[0355] In another possible implementation, when the first context information of the terminal device includes the second indication information, the core network device determines the NH and NCC according to the second indication information, and sends the second context information of the terminal device carrying the NH and NCC to the network device 2 according to the first context information of the terminal device.

[0356] In another possible implementation, when the first context information of the terminal device does not include key #1, NCC, and second indication information, the core network device generates NH and NCC, and sends the second context information of the terminal device carrying NH and NCC to the network device 2 according to the first context information of the terminal device.

[0357] It should be understood that when the core network device sends the second context information of the terminal device to network device 2, the core network device is within the coverage area of ​​network device 2 and is able to wirelessly communicate with network device 2. For example, when network device 2 moves to cover a ground gateway station, the core network device sends the second context information of the terminal device to network device 2 through the ground gateway station.

[0358] 709', Network device 2 sends an indication message to indicate its own available area.

[0359] Accordingly, the terminal device receives indication information from network device 2 indicating its own available area.

[0360] It should be understood that when a terminal device is within the coverage area of ​​network device 2, the terminal device may receive a system message broadcast by network device 2. This system message may include indication information for indicating its own available area, or the network device 2 may send the indication information for indicating its own available area through a separate message.

[0361] It should also be understood that step 709' is an optional step. If the first information in step 702 includes indication information for indicating the available area of ​​network device 2, then step 709' does not need to be performed again.

[0362] 710', The terminal device sends the first request information to the network device 2.

[0363] Accordingly, network device 2 receives the first request information from the terminal device.

[0364] For example, when a terminal device enters the coverage area of ​​network device 2, the terminal device sends a first request message to network device 2, which is used to request access to network device 2.

[0365] It should be understood that step 710' is similar to step 607 in Figure 6 and step 704 in Figure 7. For details, please refer to the detailed descriptions of step 607 in Figure 6 and step 704 in Figure 7.

[0366] 711', Network device 2 sends the first response information to the terminal device.

[0367] Accordingly, the terminal device receives the first response information from network device 2.

[0368] For example, after receiving a first request from a terminal device, network device 2 sends a first response to the terminal device based on the first request. This first response is used to respond to the first request. The first response includes the NCC from the terminal device's second context information.

[0369] It should be understood that when network device 2 accepts the access of the terminal device, network device 2 sends the first response information to the terminal device. The first response information includes NCC. The NCC is the NCC in the second context information of the terminal device received by network device 2 from the core network device. The NCC may come from network device 1, or the NCC may be determined by the core network device. This application does not limit this.

[0370] 712', The terminal device and network device 2 communicate securely.

[0371] It should be understood that after receiving the first response information from network device 2, the terminal device determines the key (e.g., key #1) for secure communication with network device 2 based on the NCC in the first response information. The key #1 determined by network device 2 may be determined by network device 1, or the key #1 determined by network device 2 based on the NH and NCC determined by the core network.

[0372] It should also be understood that the specific methods by which the terminal device determines key #1 based on NCC, and the network device 2 determines key #1 based on NCC, are similar to the method of determining KeNB* in the KeNB update in the above-mentioned 2) handover scenario (e.g., vertical derivation). Please refer to the detailed introduction above for details, which will not be repeated here.

[0373] It should also be understood that the terminal device and network device 2 use key #1 for secure communication.

[0374] According to the method shown in Figure 7 above, due to the mobility of network device 1, when the terminal device leaves the coverage area of ​​network device 1, the terminal device changes from a connected state to a first state and sends a first request message to network device 2 to request access. Considering that network device 2 has the context information of the terminal device, after receiving the first request message, network device 2 authenticates the terminal device based on the terminal device identification information in the first request message. If authentication is successful, network device 2 sends a first response message to the terminal device. The terminal device and network device 2 then communicate securely based on key #1, thereby ensuring secure communication between the terminal device and the network. Considering that network device 2 does not have the context information of the terminal device, network device 2 requests the context information of the terminal device from the core network device. The core network device requests the context information of the terminal device from network device 1, and network device 1 authenticates the terminal device. If authentication is successful, network device 1 sends the first context information of the terminal device to the core network device, and the core network device further sends the second context information of the terminal device to network device 2. Network device 2 and terminal device communicate securely based on key #1, thereby ensuring secure communication between terminal device and network.

[0375] Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application.

[0376] It should be understood that in the method shown in Figure 8, the first network device is network device 1, and at least one third network device is network device 2 and network device 3, respectively. Network device 2 can be the second network device among the at least one third network device, and network device 3 can be any other network device among the at least one third network device besides the second network device. Network device 1, network device 2, and network device 3 are all non-terrestrial network devices; for example, network device 1, network device 2, and network device 3 can be satellites or drones, and this application does not limit them. As shown in Figure 8, the method may include the following steps.

[0377] 801, Network device 1 sends T_service information to terminal device.

[0378] Accordingly, the terminal device receives T_service information from network device 1.

[0379] 802, Network device 1 sends the first information to the terminal device.

[0380] Accordingly, the terminal device receives the first information from network device 1.

[0381] 803, the terminal device changes from connected state to first state.

[0382] For example, when a terminal device receives a T_service message from network device 1, after the time indicated by the T_service message (e.g., the first time) is reached, the terminal device changes from the connected state to the first state.

[0383] It should be understood that steps 801 to 803 above are similar to steps 601 to 603 in Figure 6 above. For details, please refer to the detailed description of steps 601 to 603 above.

[0384] 804, Network device 1 sends the first context information of the terminal device to the core network device.

[0385] Accordingly, the core network device receives the first context information from the terminal device of network device 1.

[0386] For example, when network device 1 covers a ground gateway station, network device 1 sends the first context information of the terminal device to the core network device through the ground gateway station. The first context information of the terminal device includes the identification information of the UE.

[0387] In one possible implementation, when the network device 1 has an unused NH, the first context information of the terminal device includes key #1 and NCC. The key #1 is determined by the network device 1 based on the unused NH. The specific determination method is similar to the determination method of KeNB* in the KeNB update in the handover scenario described above (e.g., vertical derivation). Please refer to the detailed description above for details.

[0388] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device includes second instruction information, which is used to instruct the core network device to configure the NH and NCC for the terminal device.

[0389] In another possible implementation, if the network device 1 does not have an unused NH, the first context information of the terminal device does not include key #1, NCC, and second indication information.

[0390] 805, Network device 2 and Network device 3 send indication information to the terminal device to indicate the available area of ​​Network device 2 and the available area of ​​Network device 3.

[0391] It should be understood that step 805 is similar to step 606 in Figure 6 above, and both are optional steps. For details, please refer to the description in Figure 6 above.

[0392] 806, The terminal device sends the first request information to network device 2.

[0393] Accordingly, network device 2 receives the first request information from the terminal device.

[0394] It should be understood that step 806 is similar to step 607 in Figure 6 above, and the details can be found in the description in Figure 6 above.

[0395] 807, Network device 2 sends a second request message to the core network device.

[0396] Accordingly, the core network device receives the second request information from network device 2.

[0397] For example, after receiving the first request information from the terminal device, the network device 2 does not have the context information of the terminal device. The network device 2 sends a second request information to the core network device according to the first request information. The second request information is used to request the acquisition of the context information of the terminal device. The second request information includes the identification information of the terminal device.

[0398] It should be understood that when network device 2 covers a gateway station, network device 2 sends a second request message to the core network device through the gateway station.

[0399] 808, the core network device sends the second context information of the terminal device to network device 2.

[0400] Accordingly, network device 2 receives second context information from the terminal device of the core network device.

[0401] For example, after receiving the second request information from network device 2, the core network device authenticates the terminal device based on the terminal device's identification information in the second request information. If authentication is successful, when network device 2 covers a ground gateway station, the core network device sends the terminal device's second context information to network device 2 through the ground gateway station.

[0402] It should be understood that the core network device determines the second context information of the terminal device based on the first context information of the terminal device received in step 804. For a detailed explanation of how the core network device determines the second context information of the terminal device based on the first context information of the terminal device, please refer to the detailed explanation in step 708' in Figure 7 above, which will not be repeated here.

[0403] 809, The terminal device sends the first request information to network device 2.

[0404] Accordingly, network device 2 receives the first request information from the terminal device.

[0405] For example, when a terminal device enters the coverage area of ​​network device 2, the terminal device receives a system message broadcast by network device 2. After receiving the system message from network device 2, the terminal device can send a first request message to network device 2, which is used to request access to network device 2.

[0406] It should be understood that step 809 is similar to step 607 in Figure 6 and step 806 in Figure 8. For details, please refer to the detailed descriptions of step 607 in Figure 6 and step 806 in Figure 8.

[0407] 810, Network device 2 sends the first response information to the terminal device.

[0408] Accordingly, the terminal device receives the first response information from network device 2.

[0409] For example, after receiving a first request from a terminal device, network device 2 sends a first response to the terminal device based on the first request. This first response is used to respond to the first request. The first response includes the NCC from the terminal device's second context information.

[0410] It should be understood that when network device 2 accepts the access of the terminal device, network device 2 sends the first response information to the terminal device. The first response information includes NCC. The NCC is the NCC in the second context information of the terminal device received by network device 2 from the core network device. The NCC may come from network device 1, or the NCC may be determined by the core network device. This application does not limit this.

[0411] 811, The terminal device and network device 2 communicate securely.

[0412] It should be understood that after the terminal device receives the first response information from the network device 2, the terminal device determines the key (e.g., key #1) for secure communication with the network device 2 based on the NCC in the first response information. The key #1 determined by the network device 2 may be determined by the network device 1, or the key #1 determined by the network device 2 based on the NH determined by the core network and the NCC. This application does not limit this.

[0413] It should also be understood that the specific methods by which the terminal device determines key #1 based on NCC, and the network device 2 determines key #1 based on NCC, are similar to the method of determining KeNB* in the KeNB update in the above-mentioned 2) handover scenario (e.g., vertical derivation). Please refer to the detailed introduction above for details, which will not be repeated here.

[0414] It should also be understood that the terminal device and network device 2 use key #1 for secure communication.

[0415] According to the method shown in Figure 8 above, due to the mobility of network device 1, when the terminal device leaves the coverage area of ​​network device 1, the terminal device changes from a connected state to a first state and sends a first request message to network device 2 to request access. When network device 1 covers a ground gateway station, network device 1 can send the first context information of the terminal device to the core network device. When the core network device receives a request from another network device (e.g., network device 2) to obtain the context information of the terminal device, the core network device authenticates the terminal device. When authentication is successful, the core network device determines to send the second context information of the terminal device, determined based on the first context information of the terminal device, to network device 2, enabling network device 2 and the terminal device to communicate based on key #1, ensuring secure communication between the terminal device and the network.

[0416] Referring to the S&F scenario shown in Figure 4, to ensure that network devices in the S&F scenario only provide services to specific types of terminal devices, only S&F terminal devices can request access to network devices in the S&F scenario. Other terminal devices (such as legacy UEs or terminal devices from versions prior to R19) are not allowed / prohibited from accessing network devices in the S&F scenario. Referring to the methods shown in Figures 6 to 8, network devices 2 and 3 are network devices in the S&F scenario shown in Figure 4, and the terminal devices are S&F terminal devices.

[0417] For example, in step 606 of Figure 6, step 709' of Figure 7, and step 805 of Figure 8, the cellBarred information element in the system message (e.g., MIB message / SIB message) broadcast by network device 2 and network device 3 is set to barred. This cellBarred is used to indicate that all normal UEs (non-NTN UEs) are denied access.

[0418] It should be understood that NR introduces two special types of terminal devices: IAB-MT and NCR-MT. These two types of terminal devices may ignore the cellBarred information element in the system messages broadcast by network devices. The method provided in this application introduces the iab-support and ncr-support information elements for IAB-MT and NCR-MT in the protocols included in the system messages. The iab-support and ncr-support information elements can be located in SIB messages and are used to indicate whether the cell allows IAB-MT or NCR-MT access. For example, network devices 2 and 3 set the values ​​corresponding to the iab-support and ncr-support information elements in the SIB messages to "not support".

[0419] It should be understood that for R17 / R18 versions of NTN, the system message introduces the cellBarredNTN element, which is used to restrict NTN UE access. If the value of cellBarredNTN is notBarred, it indicates that the cell supports NTN UE access; if the value of cellBarredNTN is Barred, it indicates that the cell does not support NTN UE access. Optionally, for R19 S&F satellites, for example, in step 606 of Figure 6, step 709' of Figure 7, and step 805 of Figure 8, the cellBarredNTN element in the system message (e.g., MIB message / SIB message) broadcast by network device 2 and network device 3 is set to barred to indicate that the cell does not support ordinary NTN terminal access.

[0420] The method provided in this application introduces an indication that the cell supports S&F terminal device access. For example, a new information element (e.g., sfBarred) is introduced into the system message. This application does not limit the information element name; the value of the sfBarred information element can be "barred (prohibited)" or "not barred (not prohibited)". A value of "barred" (prohibited) for the sfBarred information element indicates that the cell does not support S&F terminal device access, while a value of "not barred" (not prohibited) indicates that the cell supports S&F terminal device access. Generally, for cells within the coverage area of ​​S&F network equipment, the value of sfBarred in the system message is set to "not barred".

[0421] Optionally, the value of the sfBarred information cell in the system message can change. If a satellite is determined to be operating in S&F mode at certain times, the value of the sfBarred information cell can be set to "not barred," indicating that the satellite provides S&F services or supports S&F terminal equipment access. However, the satellite may be determined not to be operating in S&F mode (operating in normal communication mode) at other times. For example, if the satellite can simultaneously connect to the core network and cover certain terminal equipment at certain times, then the satellite will set the value of the sfBarred information cell to "barred," indicating that the satellite does not provide S&F services or does not support S&F terminal equipment access, or that the satellite provides ordinary access services. Optionally, the cellBarredNTN cell in the system message can also be changed. When the satellite is operating in S&F mode, the values ​​of the cellBarredNTN cell and the cellBarred cell can be set to "barred". When the satellite is not operating in S&F mode, the value of the cellBarredNTN cell can be set to "not barred" and the value of the cellBarred cell can be set to "barred".

[0422] Accordingly, for terminal devices in versions prior to R19, the system message is received, and based on cellBarred=barred in the system message, it is determined that the cell is not allowed to be accessed. Consequently, the terminal device will not access the network device corresponding to that cell, i.e., it will not initiate an access request to that S&F network device. For IAB-MT and NCR-MT, the system message is received, and based on iab-support and ncr-support in the system message, it is determined that the cell is not allowed to be accessed. Consequently, IAB-MT and NCR-MT will not access the network device corresponding to that cell.

[0423] For terminal devices in R19 and later versions, if the terminal device supports S&F functionality, when determining whether the cell allows its access, it determines whether to send a first request message to the corresponding network device based on the value of the sfBarred signaling in the system message. Specifically, if the terminal device receives a system message with sfBarred = not barred, it indicates that the cell supports S&F terminal device access, or that the S&F function is enabled, meaning the cell allows access, and consequently, the terminal device can access the cell, i.e., the terminal device can send a first request message to the corresponding network device. Whether the S&F terminal device necessarily needs to read the cellBarred and / or cellBarredNTN information cells in the system message is not limited in this application.

[0424] The S&F terminal device determines whether it can request access to the network device based on system messages, including the following two possible implementations:

[0425] 1) The S&F terminal device can first read the cellBarred or cellBarredNTN information element according to the system message. If cellBarred = not barred or cellBarredNTN = not barred, the terminal device directly sends the first request information to the corresponding network device. If cellBarred = barred or cellBarredNTN = barred, the terminal device then reads the sfBarred information element in the system message to determine whether the cell allows access.

[0426] 2) S&F terminal equipment can ignore the values ​​of cellBarred and cellBarredNTN information cells, and directly read the value of sfBarred information cell in the system message to determine whether the cell allows access.

[0427] For R19 and later versions of terminal equipment, if the terminal equipment is an NTN terminal equipment that does not support S&F functionality, the cellBarred and sfBarred cells are ignored. The terminal equipment determines whether the cell allows the terminal equipment to access the cell solely based on the value of the cellBarredNTN cell. If the value of the cellBarredNTN cell is "not barred," the cell allows the terminal equipment to access the cell. If the value of the cellBarredNTN cell is "barred," the cell does not allow the terminal equipment to access the cell.

[0428] For terminal devices in Release 19 and later versions, if the terminal device is a non-NTN terminal device (e.g., a terrestrial network terminal device, a terminal device that does not support NTN functionality, or a terminal device that does not support receiving NTN network services), then the `cellBarredNTN` and `sfBarred` cells are ignored. The terminal device determines whether the cell allows the terminal device to access the cell solely based on the value of the `cellBarred` cell. If the value of the `cellBarred` cell is "not barred," the cell allows the terminal device to access the cell. If the value of the `cellBarred` cell is "barred," the cell does not allow the terminal device to access the cell.

[0429] It should be understood that the system messages broadcast by network devices in S&F scenarios combine the existing cellBarred and cellBarredNTN mechanisms to indicate that access by non-NTN UEs and non-S&F NTN UEs is denied. At the same time, the sfBarred information element has been added to the system messages broadcast by network devices. Only S&F terminal devices are allowed to access network devices in S&F scenarios, ensuring that S&F network devices only provide services to specific types of terminal devices.

[0430] The methods shown in Figures 6 to 8 above, combined with the ORAN architecture shown in Figure 1, can also be presented in the following ways in the embodiments of this application.

[0431] It should be understood that in the ORAN architecture, the RAN intelligent controller (RIC) is responsible for network device management, operation and maintenance, etc., and this RIC is similar to the Operations, Administration and Maintenance (OAM) in the existing ORAN architecture. Therefore, some OAM configuration or pre-configured information for network devices can be sent to the network devices by the RIC through the E2 interface.

[0432] For example, in conjunction with the method shown in Figure 6 above, before step 601, i.e., before network device 1 sends the T_service information to the terminal device, network device 1 receives the T_service information sent by its RIC via the E2 interface. Before step 602, i.e., before network device 1 sends the first information to the terminal device, network device 1 receives the first information sent by its RIC via the E2 interface. Before step 606, i.e., before network devices 2 and 3 send indication information for indicating available areas, network device 2 receives indication information for indicating available areas sent by its RIC via the E2 interface, and network device 3 receives indication information for indicating available areas sent by its RIC via the E2 interface.

[0433] For example, in conjunction with the method shown in Figure 7 above, before step 701, i.e., before network device 1 sends the T_service information to the terminal device, network device 1 receives the T_service information sent by its RIC via the E2 interface. Before step 702, i.e., before network device 1 sends the first information to the terminal device, network device 1 receives the first information sent by its RIC via the E2 interface. Before step 709', i.e., before network device 2 sends the indication information for indicating the available area of ​​network device 2, network device 2 receives the indication information for indicating the available area of ​​network device 2 sent by its RIC via the E2 interface.

[0434] For example, in conjunction with the method shown in Figure 8 above, before step 801, i.e., before network device 1 sends the T_service information to the terminal device, network device 1 receives the T_service information sent by its RIC via the E2 interface. Before step 802, i.e., before network device 1 sends the first information to the terminal device, network device 1 receives the first information sent by its RIC via the E2 interface. Before step 805, i.e., before network devices 2 and 3 send indication information for indicating available areas, network device 2 receives indication information for indicating available areas sent by its RIC via the E2 interface, and network device 3 receives indication information for indicating available areas sent by its RIC via the E2 interface.

[0435] It should be understood that the methods shown in Figures 6 to 8, combined with the ORAN architecture, consider how network devices can obtain relevant information through the E2 interface under the ORAN architecture. For example, the RIC of network device 1 can inform network device 1 of the T_service information and first information indicating that it is ceasing to provide services to the terminal device. The RICs of network device 2 and network device 3 can inform network device 2 and network device 3 of their corresponding available areas, thereby enabling the network devices to correctly send relevant information to the terminal device and ensuring the accuracy of the transmitted information.

[0436] The communication method provided by the embodiments of this application has been illustrated above with reference to Figures 1 to 8. In the various embodiments of this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between the various embodiments are consistent and can be referenced mutually. Technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships. For example, any two or all of Figures 5, 6, 7 and 8 can be combined.

[0437] The communication device provided in the embodiments of this application will be described in detail below with reference to Figures 9 to 11. It should be understood that the description of the device embodiments corresponds to the description of the method embodiments. Therefore, for content not described in detail, please refer to the method embodiments above. For the sake of brevity, it will not be repeated here.

[0438] Figure 9 is a schematic block diagram of a communication device 2000 provided in an embodiment of this application. The device 2000 includes a transceiver unit 2010 (or transceiver module) and a processing unit 2020 (or processing module). The transceiver unit 2010 can be used to implement corresponding transceiver functions, and the processing unit 2020 can be used to implement corresponding processing functions. The communication device can be used to execute the methods executed by the terminal device or network device in any of the embodiments shown in Figures 5 to 8.

[0439] Optionally, the transceiver unit 2020 may include a sending unit and a receiving unit. The sending unit is used to perform the sending operation in the above method embodiments. The receiving unit is used to perform the receiving operation in the above method embodiments.

[0440] Optionally, the communication device 2000 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 2020 can read the instructions and / or data in the storage unit so that the device can perform the relevant actions executed by the terminal device or network device in the aforementioned method embodiments.

[0441] In some implementations, the communication device 2000 is used to perform the actions performed by the terminal device in any of the embodiments shown in Figures 5 to 8.

[0442] For example, when a terminal device leaves the coverage area of ​​the first network device providing services to the terminal device, the processing unit 2020 is used to change the state of the communication device from a connected state to a first state, the first state including any one of the following: a suspended connected state of the access layer AS of the terminal device, a suspended idle state, or an inactive state; the transceiver unit 2010 is used to send a first request information to the second network device, the first request information being used to request access to the second network device, the first request information including the identification information of the terminal device, wherein the first network device and the second network device are non-terrestrial network devices.

[0443] The transceiver unit 2010 is also used to perform the receiving and sending processes of the terminal device in the embodiments shown in Figures 5 to 8 above; the processing unit 2020 is also used to perform other processes of the terminal device in the embodiments shown in Figures 5 to 8 above besides receiving and sending.

[0444] In some implementations, the communication device 2000 is used to perform the actions performed by the network device 1 in any of the embodiments shown in Figures 5 to 8.

[0445] For example, transceiver unit 2010 is used to send first indication information to terminal device, the first indication information being used to indicate that when the terminal device leaves the coverage area of ​​the first network device and then re-enters the coverage area of ​​the first network device, the terminal device accesses the first network device; the transceiver unit is also used to receive first request information from the terminal device, the first request information being used to request access to the first network device, wherein the first network device is a non-terrestrial network device.

[0446] It should be understood that the transceiver unit 2010 is also used to perform the receiving and sending processes of the first network device as shown in Figure 5 above.

[0447] For example, transceiver unit 2010 is used to send first information to a terminal device, the first information including at least one third network device; transceiver unit 2010 is also used to send second information to a core network device, the second information including first context information of the terminal device, the first context information of the terminal device including identification information of the terminal device, wherein the first network device and at least one third network device are non-terrestrial network devices. If the first network device has an unused next-hop NH, the first context information of the terminal device further includes: a key and a next-hop chain calculation NCC, the key being determined by the first network device based on the NH; or, if the first network device does not have an unused NH, the first context information of the terminal device further includes: second indication information, the second indication information being used to instruct the core network device to determine the NH and NCC.

[0448] The transceiver unit 2010 is also used to perform the receiving and sending processes of the first network device in the embodiments shown in Figures 6 to 8 above.

[0449] Optionally, the communication device 2000 may further include a processing unit 2020, which is used to perform other processing of the first network device in the embodiments shown in Figures 6 to 8, in addition to receiving and transmitting.

[0450] In some implementations, the communication device 2000 is used to perform the actions performed by the core network device in any of the embodiments shown in Figures 5 to 8.

[0451] For example, transceiver unit 2010 is configured to receive second information from a first network device, the second information including first context information of a terminal device, the first context information of the terminal device including identification information of the terminal device; transceiver unit 2010 is also configured to send the second context information of the terminal device to at least one third network device, the second context information of the terminal device including a key and an NCC, or the second context information of the terminal device including an NCC and a next-hop NH, wherein the key is determined according to the NH, and the first network device and at least one third network device are non-terrestrial network devices.

[0452] The transceiver unit 2010 is also used to perform the receiving and transmitting processes of the core network equipment as shown in the embodiments of Figures 6 to 8 above.

[0453] Optionally, the communication device 2000 may further include a processing unit 2020, which is used to perform other processing of the core network equipment in the embodiments shown in Figures 6 to 8, in addition to receiving and transmitting.

[0454] In some implementations, the communication device 2000 is used to perform the actions performed by the network device 2 in any of the embodiments shown in Figures 5 to 8.

[0455] For example, transceiver unit 2010 is used to receive second context information from a terminal device in the core network device; transceiver unit 2010 is used to receive first request information from the terminal device, the first request information being used to request access to the second network device, the first request information including the identification information of the terminal device, wherein the second network device is a non-terrestrial network device.

[0456] The transceiver unit 2010 is also used to perform the receiving and sending processes of the second network device in the embodiments shown in Figures 6 to 8 above.

[0457] Optionally, the communication device 2000 may further include a processing unit 2020, which is used to perform other processing of the second network device in the embodiments shown in Figures 6 to 8, in addition to receiving and transmitting.

[0458] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0459] It should also be understood that the device 2000 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 2000 can be specifically the communication device in the above embodiments, and can be used to execute the various processes and / or steps corresponding to the communication device in the above method embodiments; to avoid repetition, these will not be described again here.

[0460] The apparatus 2000 of each of the above-described schemes has the function of implementing the corresponding steps performed by the communication device (such as a terminal device or a network device) in the above-described methods. The function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the transmitting unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, each executing the transceiver operations and related processing operations in the respective method embodiments.

[0461] In addition, the transceiver unit 2020 may also be a transceiver circuit (for example, it may include a transmitting circuit or a receiving circuit), and the processing unit 2020 may be a processing circuit.

[0462] It should be noted that the device in Figure 9 can be the communication device (such as a terminal device or network device) in the foregoing embodiments, or it can be a chip or a chip system, such as a system on a chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. No limitations are imposed here.

[0463] Figure 10 shows a schematic diagram of another communication device 2100 provided in an embodiment of this application. The device 2100 includes a processor 2110 coupled to a memory 2120. The memory 2120 is used to store computer programs or instructions and / or data. The processor 2110 is used to execute the computer programs or instructions stored in the memory 2120, or to read the data stored in the memory 2120, to execute the methods in the above method embodiments.

[0464] Optionally, the processor 2110 may be one or more.

[0465] Optionally, the memory 2120 may be one or more.

[0466] Alternatively, the memory 2120 can be integrated with the processor 2110, or it can be set separately.

[0467] Optionally, as shown in FIG10, the device 2100 further includes a transceiver 2130 for receiving and / or transmitting signals. For example, a processor 2110 is used to control the transceiver 2130 to receive and / or transmit signals.

[0468] As an example, processor 2110 may have the functions of processing unit 2020 shown in FIG7, memory 2120 may have the functions of storage unit, and transceiver 2130 may have the functions of transceiver unit 2020 shown in FIG7.

[0469] As one option, the device 2100 is used to implement the operations performed by the communication device (such as a terminal device or a network device) in the various method embodiments described above.

[0470] For example, processor 2110 is used to execute computer programs or instructions stored in memory 2120 to implement the relevant operations of the communication device in the various method embodiments described above.

[0471] In some implementations, when device 2100 is a terminal device, transceiver 2130 may include a transmitter, receiver, radio frequency circuitry, antenna, and input / output devices. Processor 2110 is primarily used for processing communication protocols and data, controlling the terminal device, executing software programs, and processing software program data. Memory 2120 is primarily used for storing software programs and data. Radio frequency circuitry is primarily used for converting baseband signals to radio frequency signals and processing radio frequency signals. Antenna is primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves. Input / output devices (e.g., touchscreen, display screen, keyboard, etc.) are primarily used for receiving user input data and outputting data to the user. It should be noted that some types of terminal devices may not have input / output devices.

[0472] When data needs to be sent, the processor performs baseband processing on the data to be sent and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit then processes the baseband signal and transmits it outward as electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor. The processor then converts the baseband signal back into data and processes it.

[0473] In other implementations, when device 2100 is a network device, such as a base station, processor 2110 is mainly used for baseband processing and controlling the base station; processor 2110 is typically the control center of the base station, used to control the base station to perform the processing operations on the network device side in the above method embodiments. Memory 2120 is mainly used to store computer program code and data. Transceiver 2130 is mainly used for transmitting and receiving radio frequency signals and converting radio frequency signals to baseband signals; transceiver 2130 may include an antenna and radio frequency circuitry (not shown in the figure), wherein the radio frequency circuitry is mainly used for radio frequency processing.

[0474] In the embodiments of this application, the antenna and radio frequency circuit with transceiver function can be regarded as the transceiver module of the terminal device or network device, and the processor with processing function can be regarded as the processing module of the terminal device or network device.

[0475] In some implementations, the processor 2110 may also be referred to as a processing unit, processing board, processing module, processing device, etc. The transceiver 2130 may also be referred to as a transceiver unit, transceiver, transceiver device, etc.

[0476] When the device 2100 is a chip, the chip includes a processor, a memory, and a transceiver. The transceiver can be an input / output circuit or a communication interface; the processor can be a processing module integrated on the chip, a microprocessor, or an integrated circuit. In the above method embodiments, the sending operation of the terminal device can be understood as the output of the chip, and the receiving operation of the terminal device in the above method embodiments can be understood as the input of the chip.

[0477] It should be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0478] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0479] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) can be integrated into the processor.

[0480] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0481] Figure 11 shows a schematic diagram of a chip system 2200 provided in an embodiment of this application. The chip system 2200 (or may also be referred to as a processing system) includes logic circuitry 2210 and an input / output interface 2220.

[0482] The logic circuit 2210 can be a processing circuit in the chip system 2200. The logic circuit 2210 can be coupled to a memory unit, calling instructions from the memory unit, enabling the chip system 2200 to implement the methods and functions of the embodiments of this application. The input / output interface 2220 can be an input / output circuit in the chip system 2200, outputting processed information from the chip system 2200, or inputting data or signaling information to be processed into the chip system 2200 for processing.

[0483] As one approach, the chip system 2200 is used to implement the operations performed by the communication device (such as a terminal device or a network device) in the various method embodiments described above.

[0484] For example, logic circuit 2210 is used to implement processing-related operations performed by a communication device (such as a terminal device or a network device) in the above method embodiments; input / output interface 2220 is used to implement sending and / or receiving-related operations performed by a communication device (such as a terminal device or a network device) in the above method embodiments.

[0485] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by a communication device (such as a terminal device or a network device) in the above-described method embodiments.

[0486] For example, when the computer program is executed by a computer, it enables the computer to implement the methods executed by the communication device (such as a terminal device) in the various embodiments of the above methods.

[0487] This application also provides a computer program product comprising instructions which, when executed by a computer, implement the methods described above that are executed by a communication device (such as a terminal device or a network device).

[0488] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the explanations and beneficial effects of the relevant content in any of the communication devices provided above can be referred to the corresponding method embodiments provided above, and will not be repeated here.

[0489] To facilitate understanding of the embodiments of this application, the following points will be explained first.

[0490] I. Unless otherwise stated, “at least one” means one or more, and “more than one” means two or more.

[0491] 2. Unless otherwise specified or in case of logical conflict, the terms and / or descriptions in different embodiments of this application are consistent and can be referenced in each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0492] III. The various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of protection of this application. The magnitude of the serial numbers used in this application does not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic. For example, the terms "first," "second," "third," "fourth," and other various terminology (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0493] Furthermore, any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0494] IV. The terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or that are inherent to such process, method, product or device.

[0495] V. In this application, "for indicating" can be understood as "enabling". "Enabling" can include direct enabling and indirect enabling. When describing information for enabling A, it can include whether the information directly enables A or indirectly enables A, but it does not mean that the information necessarily carries A.

[0496] The information that enables the information is called the information to be enabled. In the specific implementation process, there are many ways to enable the information to be enabled, such as, but not limited to, directly enabling the information to be enabled, such as the information to be enabled itself or its index. It can also be indirectly enabled by enabling other information, where there is a relationship between the other information and the information to be enabled. It can also enable only a part of the information to be enabled, while the other parts are known or pre-agreed upon. For example, enabling specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various pieces of information, thereby reducing enabling overhead to some extent. Simultaneously, common parts of various pieces of information can be identified and enabled uniformly to reduce the enabling overhead caused by individually enabling the same information.

[0497] VI. In this application, "pre-configuration" may include pre-defined terms, such as protocol definitions. These "pre-defined terms" can be implemented by pre-storing corresponding codes, tables, or other means of indicating relevant information in the device (e.g., including various network elements). This application does not limit the specific implementation method.

[0498] VII. The term "storage" or "preservation" in this application can refer to storage in one or more memory devices. These memory devices can be separately configured or integrated into an encoder or decoder, processor, or communication device. Alternatively, some memory devices can be separately configured, while others can be integrated into a decoder, processor, or communication device. The type of memory can be any form of storage medium, and this is not limited.

[0499] 8. The "protocol" used in this application may refer to standard protocols in the field of communications, such as fourth-generation (4G) protocols. th Generation 4G network, fifth generation (5G) network th Generation 5G network protocol, New Radio (NR) protocol, 5.5G network protocol, sixth generation (6G) network protocol th This application does not limit the scope of network protocols (generation, 6G) and related protocols applied in future communication systems.

[0500] 9. The arrows or boxes indicated by dashed lines in the schematic diagrams in the accompanying drawings of this application represent optional steps or optional modules.

[0501] 10. Unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can mean A or B. In this application, "and / or" is merely a description of the relationship between the related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural.

[0502] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0503] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0504] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0505] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the essential contribution of the technical solution of this application, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0506] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A communication method, characterized in that, include: The second network device sends a first message, the first message including a first information element, the first information element being used to indicate whether a first type of terminal device is allowed to access the second network device, the first type of terminal device including a store-and-forward terminal device; The second network device receives a first request message from a terminal device, the first request message being used to request access to the second network device, the terminal device being a first type of terminal device, wherein the second network device is a non-terrestrial network device.

2. The method according to claim 1, characterized in that, The first message is a System Information Block (SIB).

3. The method according to claim 1 or 2, characterized in that, The first information cell is used to indicate that the first type of terminal device is allowed to access the second network device, and the second network device is operating in store-and-forward mode.

4. The method according to any one of claims 1 to 3, characterized in that, The first message also includes a second information element and / or a third information element, wherein the second information element is used to indicate whether a second type of terminal device is allowed to access the second network device, and the third information element is used to indicate whether a third type of terminal device is allowed to access the second network device. The second type of terminal equipment includes terrestrial network terminal equipment, and the third type of terminal equipment includes non-terrestrial network terminal equipment.

5. The method according to claim 4, characterized in that, In store-and-forward mode, the third information element of the second network device is a third value, which is used to indicate that the third type of terminal device is denied access to the second network device.

6. A communication method, characterized in that, include: The terminal device receives a first message, the first message including a first information element, the first information element being used to indicate whether a first type of terminal device is allowed to access the second network device, the first type of terminal device including a store-and-forward terminal device; When the first information element is used to indicate that a first type of terminal device is allowed to access the second network device, and the terminal device is a first type of terminal device, the terminal device sends a first request information to the second network device. The first request information is used to request access to the second network device, wherein the second network device is a non-terrestrial network device.

7. The method according to claim 6, characterized in that, The first message also includes a second information element and / or a third information element, wherein the second information element is used to indicate whether a second type of terminal device is allowed to access the second network device, and the third information element is used to indicate whether a third type of terminal device is allowed to access the second network device, wherein the second type of terminal device includes terrestrial network terminal devices, and the third type of terminal device includes non-terrestrial network terminal devices.

8. The method according to claim 7, characterized in that, The first message includes the second information element and the third information element. When the terminal device is the first type of terminal device, the terminal device ignores the values ​​of the second information element and the third information element in the first message, and the terminal device determines whether to send the first request information to the second network device based on the first information element.

9. The method according to claim 7, characterized in that, The first message includes the second information element and the third information element. If the terminal device is not the first type of terminal device and is the third type of terminal device, the terminal device ignores the first information element and the second information element, and the terminal device determines whether to send the first request information to the second network device based on the third information element.

10. The method according to claim 7, characterized in that, The first message includes the second information element and the third information element. If the terminal is not the first type of terminal device and the terminal device is the second type of terminal device, the terminal device ignores the first information element and the third information element, and the terminal device determines whether to send the first request information to the second network device based on the second information element.

11. A communication device, characterized in that, It includes modules for performing the method as described in any one of claims 1 to 5, or for performing the method as described in any one of claims 6 to 10.

12. A communication device, characterized in that, It includes a transceiver unit and a processing unit, wherein the transceiver unit and the processing unit are used to perform the method as described in any one of claims 1 to 5, or to perform the method as described in any one of claims 6 to 10.

13. A communication device, characterized in that, The device includes at least one processor coupled to at least one memory, the at least one processor being configured to execute a computer program or instructions stored in the at least one memory to cause the communication device to perform the method as described in any one of claims 1 to 5, or to perform the method as described in any one of claims 6 to 10.

14. A communication system, characterized in that, This includes terminal equipment and network equipment; The network device is used to perform the communication method as described in any one of claims 1 to 5; The terminal device is used to perform the communication method as described in any one of claims 6 to 10.

15. A computer-readable storage medium, characterized in that, It stores instructions or program code thereon, which, when executed by a processor, cause the processor to implement the method as described in any one of claims 1 to 5, or the method as described in any one of claims 6 to 10.

16. A chip, characterized in that, The chip includes a processor and a communication interface, the communication interface being used to send information to and / or receive information from other communication devices besides the communication device including the chip, and the processor being used to perform the method as described in any one of claims 1 to 5, or to perform the method as described in any one of claims 6 to 10.

17. A computer program product, characterized in that, The computer program product includes a computer program or instructions for performing the method as described in any one of claims 1 to 10.

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