Communication method and apparatus, and device and storage medium

Abstract

Provided in the present application are a communication method and apparatus, and a device and a storage medium. In the method, a first mobility management network element deployed in a terrestrial network generates a second key for a first satellite on the basis of a first key, and sends the second key to a mobility management network element deployed on the first satellite, such that the mobility management network element in the first satellite provides an access service for a terminal device on the basis of the second key, wherein the first key is a key that is for the terminal device and that is received by the first mobility management network element from a home subscriber service network element. On this basis, different keys are provided for different satellites, thereby implementing security isolation between different satellites and establishing a secure connection between a terminal device and a network.

Description

Communication method, apparatus, device, and storage medium

[0001] This application claims priority to the Chinese patent application No. 202411398036.X, filed on October 5, 2024, entitled “Communication method, apparatus, device, and storage medium”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

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

[0003] Due to economic or environmental factors, regions such as deserts, oceans, and remote areas cannot deploy ground networks. In order to provide better network coverage, the 3rd Generation Partnership Project (3GPP) proposes a non-terrestrial network (NTN) communication architecture. NTN communication can use satellites to network to provide network coverage for terminal devices. In the NTN communication scenario, the satellite may not be able to simultaneously transmit data with the terminal device and the ground network device, in which case the satellite needs to provide store and forward (S&F) services. In the S&F service scenario, when the service link is available, i.e., the satellite and the terminal device can transmit data, the satellite receives data from the terminal device and stores it, and then, as the satellite moves, when the satellite and the ground network can transmit data, the satellite transmits the stored data to the ground network. Alternatively, when the feeder link is available, i.e., the satellite and the ground network can communicate, the satellite receives data from the ground network and stores it, and then, as the satellite moves, when the satellite and the terminal device can communicate, the satellite transmits the stored data to the terminal device.

[0004] For S&F services, 3GPP defines a split mobility management entity (MME) architecture. In this architecture, the MME is split into MME-onboard and MME-ground, the access network and MME-onboard are deployed on the satellite, and the MME-ground and other core network elements are deployed on the ground. The MME-onboard and the MME-ground can communicate with each other through a wireless connection. Under the MME split architecture based on S&F services, due to the intermittent unavailability of the feeder link, how to ensure the safe access of the terminal device to the network for secure communication is a problem to be solved. SUMMARY

[0005] The communication method, device, equipment and storage medium provided by the embodiments of the present application enable a terminal device to access a network for secure communication.

[0006] In a first aspect, the embodiments of the present application provide a communication method. The execution subject of the method can be a first mobile management network element in a ground network, or a component (such as a chip, a chip system, a processor, etc.) configured in the mobile management network element, or a logic module or software capable of realizing all or part of the functions of the mobile management network element. For ease of understanding, the first mobile management network element is taken as the execution subject for exemplary description below.

[0007] In the method, the first mobile management network element deployed in the ground network generates a second key for a first satellite based on a first key, and sends the second key to a mobile management network element deployed on the first satellite, so that the mobile management network element in the first satellite provides access service for a terminal device based on the second key, wherein the first key is a key for the terminal device received by the first mobile management network element from a home user service network element, based on which different keys are provided for different satellites, thereby realizing secure isolation between different satellites and establishing a secure connection between the terminal device and the network.

[0008] For example, before generating the second key for the first satellite based on the first key, the first mobile management network element receives an identifier of the terminal device from the mobile management network element on the initial satellite. In this case, when the first mobile management network element determines that the terminal device needs to be authenticated, it sends an authentication data request to the home user service network element, the authentication data request including the identifier of the terminal device, and then receives an authentication data response from the home user service network element, the authentication data response including an initial authentication vector for authenticating the terminal device, the initial authentication vector including a random challenge (RAND), an authentication token (AUTN), an expected response (XRES) and the first key. Based on this, the first mobile management network element obtains the first key from the home user service network element, so as to establish a secure connection between the terminal device and the network in the S&F scenario.

[0009] Exemplarily, the first mobile management network element determines the second satellite as a candidate satellite for providing subsequent access service for the terminal device, and sends an initial authentication vector to the mobile management network element in the second satellite. The first mobile management network element provides different keys to the first satellite and the second satellite, so as to realize key isolation between satellites. Further, the first mobile management network element can send authentication vectors and subscription data to multiple candidate satellites of the terminal device, so that one of the satellites (such as the second satellite) can interact with the terminal device to complete the terminal device access to the core network. The first key of the authentication vector for each candidate satellite is different. Through this method, the success rate of the terminal device accessing the core network or the access delay can be improved.

[0010] Exemplarily, the authentication data request further includes indication information related to S&F operation, the authentication data response further includes subscription data related to S&F operation, and the initial authentication vector is carried in a message sent by the first mobile management network element to the mobile management network element in the second satellite. The message further includes subscription data related to S&F operation and a key identifier. The key identifier is used to identify the second key. The authentication vector, the subscription data, and the key identifier are simultaneously carried in the message sent by the first mobile management network element to the mobile management network element in the second satellite, so that the mobile management network element in the second satellite can authenticate the terminal device based on the message and establish a secure connection, thereby providing secure access service for the terminal device.

[0011] Exemplarily, the message further includes a globally unique temporary identity (GUTI), so that the mobile management network element in the second satellite can configure the GUTI to the terminal device after authentication.

[0012] Exemplarily, the authentication data request carries information indicating to obtain subscription data, and the authentication data request simultaneously indicates to obtain authentication vectors and subscription data, thereby reducing the number of interactions between the first mobile management network element and the home user service network element, and improving communication efficiency.

[0013] Exemplarily, the authentication data request carries information indicating a satellite identifier, and the satellite identifier is used to determine the second key, and / or the authentication data request carries information indicating a number of authentication vectors. The satellite identifier and / or the number of authentication vectors can implicitly indicate to obtain subscription data, based on which signaling overhead can be reduced.

[0014] Exemplarily, the first mobile management network element and the mobile management network element in the first satellite belong to different security domains or trust domains, that is, the first mobile management network element sends the second key to the mobile management network element in the first satellite in the case that the first mobile management network element and the mobile management network element in the first satellite belong to different security domains or trust domains, to realize the secure access of the terminal device, and the first mobile management network element can not derive the second key in the case that the first mobile management network element and the mobile management network element in the first satellite belong to the same security domain or trust domain, for example, the authentication process can be realized based on the current arbitrary implementation scheme. Similarly, when the first mobile management network element sends the corresponding second key to other candidate service satellites, it can be determined whether the satellite belongs to a different security domain from the first mobile management network element.

[0015] Exemplarily, before the first mobile management network element sends the second key to the mobile management network element in the first satellite, the first mobile management network element can also receive indication information from the mobile management network element in the second satellite, the indication information indicating that the authentication for the terminal device is successful, so that the first mobile management network element determines that the terminal device accesses the network through the access service provided by the second satellite, and then synchronizes the first second key to the mobile management network element in the first satellite, to realize the key isolation between the first satellite and the second satellite, thereby ensuring the security of the terminal device communicating through different satellites and preventing key stream reuse.

[0016] Exemplarily, the indication information is also used to indicate the authentication vector corresponding to the second key, and then the first mobile management network element can delete the authentication vector corresponding to the first key, thereby ensuring the freshness of the authentication vector.

[0017] Optionally, the initial satellite and the second satellite are different satellites or the same satellite, which is not limited in the application.

[0018] Optionally, the first satellite and the second satellite are different satellites to realize the access service of the service satellite switching.

[0019] Exemplarily, the first mobile management network element can send the derived authentication vector to the mobile management network element in the first satellite, the derived authentication vector including RAND, AUTN, XRES and the second key. Thus, the first key is prevented from being leaked to the first satellite, and the secure access of the terminal device is realized.

[0020] Optionally, the initial satellite and the first satellite are different satellites or the same satellite, which is not limited in the application.

[0021] Exemplarily, the first mobile management network element can generate the second key using the first key and a first input parameter; wherein the first input parameter comprises one or more of the following: an identity of the first satellite, an identity of the mobile management network element in the first satellite, or a key identifier; wherein the key identifier is used to identify the second key. This makes different second keys generated for different satellites, and realizes key isolation between satellites.

[0022] Exemplarily, the first key is a root key K ASME Based on this, in this embodiment, the second key sent by the first mobile management network element to the mobile management network element in the satellite is derived based on the root key, thereby avoiding leakage of the root key and ensuring that the terminal device securely accesses the network.

[0023] In a second aspect, an embodiment of the present application provides a communication method. The execution subject of the method can be a terminal device, or a component (such as a chip, a chip system, a processor, etc.) configured in the terminal device, or can realize all or part of the functions or software of the terminal device. For ease of understanding, the terminal device is exemplarily described below as the execution subject.

[0024] In the method, the terminal device generates a second key for the first satellite according to a first key in the process of connecting to the mobile management network element in the first satellite; wherein the first key is a key generated in the process of the terminal device attaching to the mobile management network element in the second satellite; and generates a non-access layer (NAS) key according to the second key, the NAS key being used to protect messages between the terminal device and the mobile management network element in the first satellite; wherein the NAS key comprises a NAS encryption key and a NAS integrity protection key. Optionally, the terminal device generates the second key for the first satellite before connecting to the first satellite, and generates the NAS key according to the second key in the process of connecting to the mobile management network element in the first satellite.

[0025] Exemplarily, the terminal device can receive a first NAS message from a mobility management network element in the first satellite, the first NAS message being used to indicate to establish a secure connection; the first NAS message comprises a NAS integrity protection algorithm and a NAS encryption algorithm; and generate a NAS integrity protection key according to the second key and the NAS integrity protection algorithm, and generate a NAS encryption key according to the second key and the NAS encryption algorithm; the method further comprises: the terminal device verifies the integrity of the first NAS message according to the NAS integrity protection key and the NAS integrity protection algorithm, and in the case of passing the integrity verification, sends a second NAS message to the mobility management network element of the first satellite, the second NAS message being used to respond to the indication to establish a secure connection. Exemplarily, the first NAS message can be a security mode command message, and the second NAS message can be a security mode complete message.

[0026] Exemplarily, the first NAS message further comprises a key identifier, wherein the key identifier is used to identify the second key; the terminal device can generate the second key according to the first key and the key identifier.

[0027] Exemplarily, the first NAS message further comprises an identifier of a mobility management network element of the second satellite; the terminal device can generate the second key for the first satellite according to the first key and the identifier of the mobility management network element of the first satellite.

[0028] Exemplarily, the terminal device can receive a broadcast message, the broadcast message comprising an identifier of the first satellite; and generate the second key for the first satellite according to the first key and the identifier of the first satellite.

[0029] Exemplarily, the method further comprises: the terminal device stores the correspondence between the NAS key and the first satellite.

[0030] Exemplarily, the method further comprises: when leaving the first satellite and communicating with the mobility management network element in the first satellite again, the terminal device uses the stored NAS key between the terminal device and the mobility management network element in the first satellite.

[0031] Exemplarily, the first satellite and the second satellite are the same satellite or different satellites.

[0032] Exemplarily, the first key is a root key K ASME .

[0033] In a third aspect, an embodiment of the present application provides a communication method. An execution subject of the method can be a mobility management network element in a first satellite, or a component (such as a chip, a chip system, a processor, etc.) configured in the mobility management network element, or a logic module or software capable of implementing all or part of functions of the mobility management network element. For ease of understanding, the following exemplary description is made with the mobility management network element in the first satellite as the execution subject.

[0034] In one implementation of the method, the mobility management network element in the first satellite receives a second key from a first mobility management network element, the second key being generated based on a first key for the first satellite, the first key being a key for a terminal device received by the first mobility management network element from a home user service network element, and the first satellite being a candidate satellite for subsequently providing access services for the terminal device; the mobility management network element in the first satellite generates a NAS key based on the second key, the NAS key being used to protect messages between the terminal device and the mobility management network element in the first satellite; and the NAS key includes a NAS encryption key and a NAS integrity protection key.

[0035] For example, the mobility management network element in the first satellite generates the NAS encryption key based on the second key and a NAS encryption algorithm, and generates the NAS integrity protection key based on the second key and a NAS integrity protection algorithm; sends a first NAS message protected based on the NAS encryption key and the NAS integrity protection key to the terminal device, the first NAS message being used to indicate establishment of a secure connection, and the first NAS message including the NAS integrity protection algorithm and the NAS encryption algorithm; receives a second NAS message from the terminal device, the second NAS message being used to indicate establishment of the secure connection; and the mobility management network element in the first satellite verifies integrity of the second NAS message based on the NAS integrity protection key and the NAS integrity protection algorithm, thereby completing establishment of the secure mode.

[0036] In another implementation of the method, the mobility management network element in the first satellite receives a NAS key from a first mobility management network element, the NAS key being generated based on a second key for the first satellite, the second key being generated based on a first key for the first satellite, the first key being a key for a terminal device received by the first mobility management network element from a home user service network element, and the first satellite being a candidate satellite for subsequently providing access services for the terminal device.

[0037] For example, the mobile management network element in the first satellite sends a first NAS message protected based on a NAS encryption key and a NAS integrity protection key to the terminal device, the first NAS message is used to indicate to establish a secure connection, the first NAS message includes a NAS integrity protection algorithm and a NAS encryption algorithm; then, the mobile management network element in the first satellite receives a second NAS message from the terminal device, the second NAS message is used to indicate to establish a secure connection; finally, the mobile management network element in the first satellite checks the integrity of the second NAS message according to the NAS integrity protection key and the NAS integrity protection algorithm, thereby completing the establishment of the security mode.

[0038] For example, the mobile management network element in the first satellite can store the correspondence between the NAS key and the terminal device.

[0039] For example, when the terminal device leaves the first satellite and communicates with the mobile management network element in the first satellite again, the mobile management network element in the first satellite can protect the messages between the terminal device and the mobile management network element using the stored NAS key.

[0040] Optionally, the first satellite and the second satellite are the same satellite or different satellites.

[0041] For example, the first key is a root key K ASME .

[0042] In a fourth aspect, an embodiment of the present application provides a communication method. The execution subject of the method can be a home user service network element, or a component (such as a chip, a chip system, a processor, etc.) configured in the home user service network element, or a logic module or software capable of realizing all or part of the functions of the home user service network element. For ease of understanding, the home user service network element is exemplarily described as the execution subject below.

[0043] In an implementation form of the method, the home user service network element can receive an authentication data request from the first mobile management network element, the authentication data request including an identifier of the terminal device; and send an authentication data response to the first mobile management network element, the authentication data response including an initial authentication vector used to authenticate the terminal device, the initial authentication vector including RAND, AUTN, XRES and a first key, the first key being a key received by the first mobile management network element from the home user service network element for the terminal device.

[0044] In another implementation form of the method, the home user service network element can receive an authentication data request from the first mobile management network element, the authentication data request comprising the identity of the terminal device and the first input parameter; and send an authentication data response to the first mobile management network element, the authentication data response comprising a derived authentication vector for authenticating the terminal device, the derived authentication vector comprising RAND, AUTN, XRES and a second key, the second key being a key generated based on the first key for the first satellite.

[0045] For example, the authentication data request carries information indicating to obtain the subscription data, and correspondingly, the authentication data response further comprises the subscription data of the terminal device.

[0046] For example, the authentication data request carries information indicating the satellite identity and / or information indicating the number of authentication vectors to be obtained.

[0047] For example, the information indicating the satellite identity and / or the information indicating the number of authentication vectors to be obtained carried in the authentication data request is used to implicitly indicate to obtain the subscription data.

[0048] In a fifth aspect, an embodiment of the present application provides a communication apparatus, including: a module for performing the method in the first aspect, the second aspect, the third aspect, the fourth aspect or the possible implementation forms.

[0049] In a sixth aspect, an embodiment of the present application provides a communication apparatus, including: a processor for performing the method in the first aspect, the second aspect, the third aspect, the fourth aspect or the possible implementation forms by running a computer program or by a logic circuit.

[0050] In a possible implementation form, the communication apparatus further includes: a memory for storing the computer program.

[0051] In a possible implementation form, the communication apparatus further includes: a communication interface for inputting and outputting signals.

[0052] In a seventh aspect, an embodiment of the present application provides a chip, including: a processor for calling and running computer instructions from a memory, so that a device installed with the chip performs the method in the first aspect, the second aspect, the third aspect, the fourth aspect or the possible implementation forms.

[0053] In an eighth aspect, an embodiment of the present application provides a computer readable storage medium for storing computer program instructions, the computer program instructions causing a computer to perform the method in the first aspect, the second aspect, the third aspect, the fourth aspect or the possible implementation forms.

[0054] In a ninth aspect, an embodiment of the present application provides a computer program, which causes a computer to execute the method in the first aspect, the second aspect, the third aspect, the fourth aspect, or the possible implementation manners.

[0055] In a tenth aspect, an embodiment of the present application provides a computer program product, which includes computer program instructions, and the computer program instructions cause a computer to execute the method in the first aspect, the second aspect, the third aspect, the fourth aspect, or the possible implementation manners.

[0056] The beneficial effects of the second aspect to the tenth aspect and the possible implementation manners can refer to the beneficial effects brought by the first aspect and the possible implementation manners of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0057] FIG. 1 shows a network architecture diagram of an NTN;

[0058] FIG. 2 is a network architecture diagram of a split MME in an evolved packet system network according to an embodiment of the present application;

[0059] FIG. 3 is a communication link diagram in an NTN scenario according to an embodiment of the present application;

[0060] FIG. 4 is a flow diagram of a terminal device accessing a core network according to an embodiment of the present application;

[0061] FIG. 5 is a flow diagram of a terminal device accessing a core network according to an embodiment of the present application;

[0062] FIG. 6 is a schematic flow diagram of a communication method according to an embodiment of the present application;

[0063] FIG. 7 is a flow diagram of another communication method according to an embodiment of the present application;

[0064] FIG. 8 is a flow diagram of another communication method according to an embodiment of the present application;

[0065] FIG. 9a is a flow diagram of another communication method according to an embodiment of the present application;

[0066] FIG. 9b is a flow diagram of another communication method according to an embodiment of the present application;

[0067] FIG. 10 is a diagram of key generation according to an embodiment of the present application;

[0068] FIG. 11 is a flow diagram of another communication method according to an embodiment of the present application;

[0069] FIG. 12 is a schematic block diagram of a communication apparatus according to an embodiment of the present application;

[0070] FIG. 13 is another schematic block diagram of a communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0071] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0072] FIG. 1 shows a schematic diagram of a network architecture of a non-terrestrial network (NTN). As shown in FIG. 1, in the NTN network architecture, different architectures can be divided according to the nodes deployed on the satellite, for example, a split MME EPS architecture can include a terminal device, a satellite deployed with a base station and MME-onboard, a ground station and a core network including MME-ground, the terminal device accesses to the core network through the base station deployed on the satellite, MME-onboard and the ground station deployed on the ground, wherein the ground station can also be referred to as a gateway station.

[0073] In the network architecture as shown in FIG. 1, the link between the terminal device and the satellite can be referred to as a service link (service link) or a traffic link, and the link between the satellite and the ground station can be referred to as a feeder link (feeder link) or a feeder link.

[0074] In the embodiments of the present application, the terminal device can also be referred to as a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent or a user device.

[0075] The terminal device can be a device providing voice / data, for example, a handheld device with wireless connection function, a vehicle-mounted device, etc. At present, some examples of terminals are: mobile phone, tablet computer, notebook computer, palm computer, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, wearable device, terminal device in a 5G network, or terminal device in a future evolved public land mobile network (PLMN), etc. The embodiments of the present application are not limited thereto.

[0076] By way of example and not limitation, in the embodiments of the present application, the terminal device can also be a wearable device. The wearable device can also be referred to as a wearable smart device, which is a general term for devices that are designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing, and shoes. The wearable device is a portable device that is directly worn on the body or integrated into the user's clothes or accessories. The wearable device is not only a hardware device, but also a device that realizes powerful functions through software support and data interaction and cloud interaction. The general wearable smart device includes devices with full functions, large size, and the ability to realize complete or partial functions without relying on a smart phone, such as smart watches or smart glasses, and devices that focus on a certain application function and need to be used in cooperation with other devices, such as smart phones, such as various smart wristbands and smart jewelry for monitoring vital signs.

[0077] In the embodiments of the present application, the apparatus for implementing the function of the terminal device can be a terminal device, or can be an apparatus capable of supporting the terminal device to implement the function, for example, a chip system, which can be installed in the terminal device or used in matching with the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or can include the chip and other discrete devices. In the embodiments of the present application, only the apparatus for implementing the function of the terminal device is taken as an example for description, and the scheme of the embodiments of the present application is not limited in this way.

[0078] The base station in the embodiments of the present application can be a device for communicating with a terminal device, and the base station can also be referred to as an access network device or a radio access network device. The base station in the embodiments of the present application can refer to a radio access network (RAN) node (or device) for accessing a terminal device to a wireless network. The base station can broadly cover various names in the following or be replaced by the following names, such as: Node B (NodeB), evolved Node B (eNB), next generation Node B (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), primary station, secondary station, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), radio unit (RU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, modem or chip for being arranged in the foregoing device or apparatus. The base station can also be a mobile switching center, a device assuming a base station function in D2D, V2X, M2M communication, a network side device in a 6G network, a device assuming a base station function in a future communication system, etc. The base station can support networks of the same or different access technologies. Optionally, the RAN node can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in vehicle to everything (V2X) technology can be a road side unit (RSU). The embodiments of the present application do not limit the specific technology and specific device form of the network device.In some deployments, the network device mentioned by embodiments of the present application can be a device including a CU, or a DU, or a device including a CU and a DU, or a control plane CU node (central unit-control plane (CU-CP)) and a user plane CU node (central unit-user plane (CU-UP)) and a DU node. For example, the network device can include a gNB-CU-CP, a gNB-CU-UP and a gNB-DU.

[0079] In some deployments, wireless access by a terminal is assisted by cooperation of multiple RAN nodes, and different RAN nodes respectively implement part of the functions of a base station. For example, the RAN node can be a CU, a DU, a CU-CP, a CU-UP, or an RU, etc. The CU and the DU can be separately arranged, or can also be included in the same network element, for example, in a BBU. The RU can be included in a radio frequency device or a radio frequency unit, for example, included in an RRU, an AAU or an RRH.

[0080] The RAN node can support one or more types of front interfaces, and different front interfaces respectively correspond to DUs and RUs with different functions. If the front interface between the DU and the RU is a common public radio interface (CPRI), the DU is configured to implement one or more of the baseband functions, and the RU is configured to implement one or more of the radio frequency functions. If the front interface between the DU and the RU is another interface, compared with the CPRI, part of the baseband functions of the downlink and / or uplink, such as one or more of precoding, digital beamforming (BF), or fast inverse fast Fourier transform (IFFT) / adding a cyclic prefix (CP) for the downlink, or one or more of digital beamforming (BF), or fast Fourier transform (FFT) / removing a cyclic prefix (CP) for the uplink, are moved from the DU to the RU for implementation. In a possible implementation, the interface can be an enhanced common public radio interface (eCPRI). Under the eCPRI architecture, the splitting manner between the DU and the RU is different, corresponding to different categories (Cat) of eCPRI, such as eCPRI Cat A, B, C, D, E, F.

[0081] In a possible design, a processing unit for implementing baseband functions in a BBU is referred to as a base band high (BBH) unit, and a processing unit for implementing baseband functions in an RRU / AAU / RRH is referred to as a base band low (BBL) unit.

[0082] In different systems, the CU (or CU-CP and CU-UP), DU, or RU can also have different names, but a person skilled in the art can understand the meanings thereof. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. Any of the CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0083] In an embodiment of this application, the apparatus for implementing the function of a base station can be a base station, or can be an apparatus capable of supporting the base station to implement the function, for example, a chip system, a hardware circuit, a software module, or a hardware circuit plus a software module. The apparatus can be installed in the base station or used in matching with the base station. In this application, only the base station is taken as an example for description, and the scheme of this application is not limited in this way.

[0084] FIG. 2 is a schematic diagram of a network architecture of a split MME in an evolved packet system (EPS) network according to an embodiment of the present application. As shown in FIG. 2, in the network architecture of the split MME, there are terminal devices, n satellites (e.g., satellite 1 to satellite n), and a core network. On each satellite, there are a radio access network (e.g., an evolved universal terrestrial radio access network (E-UTRAN)) and an MME on the satellite (e.g., an MME-onboard, referred to as an onboard MME). In the core network, there are multiple network elements, including an MME in the ground network (e.g., an MME-ground, referred to as a ground MME), a serving gateway (SGW), a home subscriber server (HSS), a short message service gateway mobile switching center (SMS-GMSC) / interworking mobile switching center (IW MSC) / SMS router, an interworking function (IWF) / service capability exposure function (SCEF), a policy and charging rules function (PCRF), a packet data network gateway (PGW), a data network (DN) / cellular internet of things service (CloT) service. The satellite and the core network can exchange information through a ground station. For example, after receiving a signal from the satellite, the ground station can perform protocol conversion, signal modulation, and the like on the received signal, so that the data from the satellite can be successfully transmitted to the network elements in the core network, such as the ground MME.

[0085] Referring to FIG. 2, the link between the MME-onboard and the MME-ground is a feeder link. The link between the terminal device and the E-UTRAN is a service link.

[0086] The MME-onboard handles signaling and / or data transmitted over the S1 interface between the MME-onboard and the E-UTRAN, and handles non-access stratum (NAS) signaling and / or data received from a terminal device via the onboard E-UTRAN or transmitted to a terminal device via the onboard E-UTRAN.

[0087] The MME-ground handles signaling and / or data transmitted over the interfaces between the MME-ground and other core network functions (e.g., S6a to HSS, SGd to SMS-GMSC / IWMSC / SMS router, T6a to SCEF, T6ai to IWF-SCEF, S11 to SGW). One MME-ground can be associated with one or more MME-onboard.

[0088] The above description of various network elements in the NTN network and interfaces between the various network elements is only exemplary and should not constitute any limitation on the present application. In addition, the various network elements shown in FIG. 2 can be separate devices or can be integrated into the same device to implement different functions. The specific form of the network elements is not limited in the present application. Network elements applied in future communication systems that have the same or similar functions as the above network elements are within the scope of the present application.

[0089] It can be understood that in the NTN network architecture, the movement of the service satellite can cause the service link to be connected and the feeder link to be disconnected, or the feeder link to be connected and the service link to be disconnected. As shown in FIG. 3, at T1, when the satellite moves to position 1, the service link is connected and the feeder link is disconnected; at T2, when the satellite moves to position 2, neither the service link nor the feeder link is connected; at T3, when the satellite moves to position 3, the feeder link is connected and the service link is disconnected. That is, in the NTN network, the service link and / or the feeder link of the satellite can not be available at all times.

[0090] In such a scenario where the feeder link of the service satellite is discontinuous, the 3rd generation partnership project (3GPP) R19 introduces a kind of S&F satellite operation, which is an operation of providing communication services to a terminal device in a time period and / or a physical area where the service satellite is not simultaneously connected to the ground network. The mode in which the terminal device, the radio access network element and the core network element perform the S&F operation can be referred to as the S&F mode.

[0091] In S&F satellite operation, the end-to-end exchange of signaling / data traffic is handled as a combination of two or more steps that are not concurrent in time. First, the signaling / data exchange between the terminal device and the satellite takes place, but at this time the satellite is not connected to the ground network via the feeder link. Next, the satellite moves and establishes a connection with the ground network, the satellite and the ground network communicate, and the end-to-end exchange is completed.

[0092] For ease of description, the base station / access device deployed on the satellite are all referred to as base stations, that is, the base station in the following specifically refers to the base station / access device deployed on the satellite.

[0093] After the terminal device initiates the access core network process, under the MME split architecture based on the S&F service, due to the intermittent unavailability of the feeder link, the MME-ground needs to synchronize the context for communication with the terminal device to the MME-onboard serving the satellite during the process of the terminal device accessing the core network. Since at different times, the terminal device can access the network and transmit data through the MME-onboard of different serving satellites, in this scenario, the MME-ground needs to synchronize the context of the terminal device to the MME-onboard of different serving satellites in advance, and the use of the same security context on different MME-onboard will cause the problem of key stream reuse. In this case, how to ensure the security of data transmission of the terminal device through different satellites is a problem to be solved.

[0094] It should be noted that, for ease of description, the terminal device interacts with the MME through the forwarding of the base station, which can be expressed as the terminal device interacting with the MME, such as the terminal device sending information to the MME-onboard through the forwarding of the base station, which can be expressed as the terminal device sending information to the MME-onboard; the MME-onboard sends information to the terminal device through the forwarding of the base station, which can be expressed as the MME-onboard sending information to the terminal device.

[0095] In the embodiments of the present application, the same items or similar items with basically the same functions and roles are distinguished by "first", "second", and the like, and the sequence and number are not limited, and "first", "second", and the like do not necessarily mean different. In the embodiments of the present application, "first", "second", and the like can also distinguish different keys, messages, indication information, network elements, requests, and the like in the following.

[0096] In the embodiments of the present application, "at least one" can include one or more, and "multiple" in the embodiments of the present application includes two or more.

[0097] The communication method provided in the application is described below with reference to the accompanying drawings. The MME-ground provides different keys for different satellites, thereby realizing the secure isolation between different satellites and establishing a secure connection between the terminal device and the network.

[0098] Before describing the communication method provided in the application in detail, the process of terminal device access to the core network is first described in detail below with reference to FIGS. 4 and 5. The process of terminal device access to the core network is also referred to as the network access process of the terminal device.

[0099] FIG. 4 is a flowchart of the process of terminal device access to the core network according to an embodiment of the application. The method shown in FIG. 4 includes S410 to S440. The steps in FIG. 4 are described in detail below.

[0100] S410, when the terminal device accesses the network, the terminal device first performs cell search and selection.

[0101] Optionally, the cell search is that the terminal device detects the broadcast message of the base station. The broadcast message can include a physical cell identifier (PCI), a master information block (MIB), a system information block / system information broadcast. The PCI is used to determine the cell, and one or more of the PCI, the MIB, and the system information block / system information broadcast are combined to be the information necessary for the terminal device to camp on the cell and initiate initial access.

[0102] After the cell search is completed, the terminal device selects a cell and acquires downlink synchronization with the cell.

[0103] For the NTN scenario, through the above broadcast message, the terminal device can perceive the information of the network, such as information that the network supports S&F satellite operation and the identity of the satellite where the base station is located.

[0104] S420, the terminal device performs a random access process.

[0105] The random access process is used for the terminal device to acquire uplink synchronization with the cell.

[0106] For example, in this process, the base station allocates uplink resources for the terminal device to send an RRC setup request (RRC Setup Request). The terminal device can initiate uplink transmission only after obtaining the uplink resources.

[0107] S430, after the terminal device successfully performs the random access, the terminal device establishes an RRC connection with the base station.

[0108] For example, the terminal device sends an RRC Setup Request to the base station on a signaling radio bearer (SRB) 0 (SRB0); the base station sends an RRC Setup to the terminal device after receiving the RRC Setup Request, and the RRC Setup carries detailed information of SRB1 resource configuration; the terminal device sends an RRC Setup Complete to the base station after receiving the RRC Setup to indicate that the terminal device and the base station successfully establish an RRC connection.

[0109] The SRB0 does not need to be established and exists all the time, and is used to carry RRC signaling before the RRC connection is successfully established and is transmitted through a common control channel (CCCH).

[0110] The SRB1 is used to carry RRC signaling after the RRC connection is successfully established and NAS signaling before the SRB2 is established, and is transmitted through a dedicated control channel (DCCH). The SRB2 is used to carry NAS signaling and is transmitted through a DCCH logical channel. The priority of the SRB2 is lower than that of the SRB1, and the SRB2 can be established only after a security mode is activated. The SRB2 is established through RRC reconfiguration. The NAS signaling is signaling for transmitting information between the terminal device and a core network element, and the base station is only responsible for forwarding. The signaling is above the RRC layer, and the NAS signaling can occur only after the RRC connection is successfully established.

[0111] That is, the purpose of establishing the RRC connection is to establish the SRB1, and then the RRC signaling after the RRC connection is successfully established is transmitted through the SRB1.

[0112] After the RRC connection is successfully established, the terminal device and the base station each save a copy of the RRC context, including an identifier of the terminal device, such as a cell radio network temporary identifier (C-RNTI), resource information of the SRB, and the like.

[0113] The steps 410 to 430 can also be referred to as a process of the terminal device accessing the base station. That is, the process of the terminal device accessing the base station includes cell selection, random access, and establishment of the RRC connection.

[0114] S440: The terminal device establishes a connection with the core network to access the core network.

[0115] Exemplarily, a process of establishing a connection between a terminal device and a core network is shown in FIG. 5. In 4G, the process of establishing a connection between a terminal device and a core network is also called an Attach process, and in 5G, the process of establishing a connection between a terminal device and a core network is also called a Registration process. The embodiments of the present application can be applicable to the Attach process in 4G and the Registration process in 5G, and other relevant access processes with other names in future communication systems. FIG. 5 takes the Attach process implemented in 4G as an example for illustration.

[0116] As shown in FIG. 5, the process of establishing a connection between a terminal device and a core network includes S510-S570.

[0117] At T1, the service link between the terminal device and the satellite is available, and the feeder link between the satellite and the ground core network is unavailable.

[0118] S510, the terminal device sends a first Attach Request to the MME-onboard to request access to the core network. The first Attach Request can be an initial Attach Request or an initial access request. Optionally, the Attach Request information can include an international mobile subscriber identity (IMSI), S&F capability information and / or security capability of the terminal device. The S&F capability information can indicate whether the terminal device has S&F capability or whether the terminal device supports S&F operation, or the S&F capability information indicates that the terminal device has S&F capability or the terminal device supports S&F operation, in which case the S&F capability information is carried in the Attach Request information when the terminal device has S&F capability. The security capability of the terminal device is used to indicate the encryption algorithm and / or integrity protection algorithm supported by the terminal device.

[0119] The terminal device can determine to send the first Attach Request to the MME-onboard according to the broadcast message in S410, and include the S&F capability information in the first Attach Request.

[0120] S520, the MME-onboard sends a first Attach Response.

[0121] In the process of initial access of the terminal device, the MME-onboard does not have the context of the terminal device, and the first attachment response can be an attachment rejection (Attach Reject) message. Optionally, the MME-onboard can include S&F waiting timer and / or monitoring list information in the attachment rejection message according to the S&F capability information in the first attachment request. The terminal device can initiate a new attachment request after the S&F waiting timer ends, and cannot initiate a new attachment request before the S&F waiting timer ends. The monitoring list includes information of at least one NTN device that the terminal device can access, such as satellite identification, frequency band, cell information, and one or more information used by the terminal device to determine whether it can access. After receiving the attachment rejection message containing the monitoring list, the terminal device can perform monitoring operations as required to re-initiate an attachment request or obtain other necessary network information at the appropriate time.

[0122] The S&F waiting timer and the monitoring list can be determined based on ephemeris information. The ephemeris information is the motion law information of the satellite, for example, including the orbital parameters, angular velocity, and / or velocity of the satellite, and the MME-onboard can calculate the position of the satellite on the orbit at each moment based on these information. The ephemeris information can be represented as a simple correspondence, for example, the satellite position information corresponding to each moment / time period. The ephemeris information can also be represented as a satellite coverage map, for example, satellite coverage availability information. The satellite coverage map can divide the earth's surface into multiple grid points and show the grid points covered and not covered by the satellite at each moment.

[0123] At T2, the feeder link between the satellite and the ground core network is available, and the service link between the terminal device and the satellite is unavailable.

[0124] S530, the MME-onboard, the MME-ground, and the HSS perform a process of obtaining authentication information and subscription data.

[0125] In S530, the following steps S531-S536 can be included:

[0126] S531, the MME-onboard sends an attach request or trigger message to the MME-ground, which carries information that can be obtained from the first attach request described above, such as the IMSI of the terminal device and / or the S&F capability information. Alternatively, the attach request or trigger message is the first attach request described above, i.e., the MME-onboard forwards the first attach request received from the terminal device to the MME-ground. Optionally, the MME-onboard also sends the identity of the network selected by the terminal device, such as the PLMN ID, to the MME-ground.

[0127] S532, the MME-ground sends an authentication data request to the HSS, which includes the IMSI of the terminal device, part or all of the serving network identity (SN ID) or network type.

[0128] S533, the HSS sends an authentication data response to the MME-ground. The HSS obtains an authentication vector (AV) and sends the authentication data response carrying the AV to the MME-ground.

[0129] Optionally, the AV can include: RAND, AUTN, XRES and a security management entity key K ASME The AV can also include: a cipher key (CK) and an integrity protection key (IK), where K ASME is a root key derived from the CK / IK and the serving network identity.

[0130] S534, when the terminal device is in a communication scenario operating on the S&F satellite, the MME-ground sends an update location request to the HSS to update the location of the terminal device to obtain the subscription data of the terminal device.

[0131] Optionally, the update location request includes an indication that this location update is temporary, i.e., the HSS does not consider the terminal device as registered until it receives the final update location request.

[0132] S535, the HSS sends an update location response to the MME-ground. The update location response carries the subscription data of the terminal device.

[0133] S536, the MME-ground sends a response message to the MME-onboard, which can include the IMSI of the terminal device, authentication information (such as AV) and subscription data.

[0134] At T3, the service link between the terminal device and the satellite is available, and the feeder link between the satellite and the ground core network is unavailable.

[0135] At S540, the terminal device sends a second attach request to the MME-onboard. The second attach request can carry the same information as the first attach request.

[0136] Optionally, after the S&F timer expires, the terminal device can send an initial attach request to the MME-onboard to attempt to re-register to the network.

[0137] At S550, an authentication procedure is performed between the terminal device and the MME-onboard.

[0138] Optionally, the MME-onboard authenticates or authenticates the terminal device using the stored AV from the MME-ground.

[0139] At S550, the following steps S551-S552 can be included:

[0140] At S551, the MME-onboard sends a user authentication request to the terminal device.

[0141] Optionally, the user authentication request can carry the RAND and AUTN in the AV.

[0142] At S552, the terminal device sends a user authentication response to the MME-onboard.

[0143] After the terminal device receives the RAND and AUTN, it checks the validity of the AUTN, such as verifying whether the sequence number (SQN) therein is within an acceptable range. If the sequence number is out of range, it can indicate that the authentication token has expired or there can be a replay attack, and the terminal device will abandon the registration procedure and send an authentication failure message to the MME-onboard.

[0144] The terminal device can also use the stored key and a specific algorithm to verify part of the information in the AUTN to verify the legitimacy of the network. If the calculation result matches certain fields in the AUTN, the network is considered legitimate; otherwise, the terminal device will refuse authentication and send an authentication failure message to the MME-onboard.

[0145] When the terminal device considers the AUTN valid and the verification is passed, the identity authentication process is continued, such as calculating a response value (RES) according to the received RAND, and sending the RES to the MME-onboard. The RES can be carried in the user authentication response described above. Further, after receiving the RES of the terminal device, the MME-onboard compares the XRES in the AV. The XRES and the RES are generated based on the same algorithm and input parameters, for example, the HSS calculates the XRES based on the root key (such as K) shared by the terminal device and the network according to a specific algorithm, and correspondingly, the terminal device calculates the RES based on the root key (such as K) shared by the terminal device and the network according to a specific algorithm. The application does not limit the algorithm used to generate the XRES and the RES, such as the MILENAGE algorithm of the algorithm set specified by 3GPP for authentication and key generation in a mobile communication network. If the XRES and the RES are consistent, the identity authentication is successful; otherwise, the authentication fails.

[0146] S553, the MME-onboard sends an integrity-protected security mode command to the terminal device. The security mode command is used to negotiate a security algorithm and instruct the terminal device to start security protection to protect subsequent communication. The security mode command may, for example, include security algorithm indication and / or key identification information, etc.

[0147] S554, the terminal device sends an integrity-protected and encrypted security mode response to the MME-onboard. Optionally, the security mode response can include confirmation information, such as confirming that the security mode command has been successfully received and processed.

[0148] S560, the MME-onboard sends a second attach response, such as an attach accept, to the terminal device.

[0149] The attach accept information is used to indicate that the core network side accepts the terminal device's request to enter the network, or is also referred to as the core network side allowing the terminal device to enter the network.

[0150] Optionally, the second attach response also includes the GUTI of the terminal device.

[0151] It can be understood that when the terminal device receives the attach accept information sent by the MME-onboard, the terminal device replies to the MME through the base station with an initial access completion message, and after the MME receives this message and performs actions such as configuring a bearer, the initial access process is completed.

[0152] In the S&F satellite operation, S510 and S520 described above can be performed when the service link is connected, S530 described above can be performed when the feeder link is connected, and S540 to S560 described above can be performed when the service link is connected.

[0153] Hereinafter, the communication method provided by the present application is described in detail.

[0154] FIG. 6 is a schematic flowchart of a communication method provided by an embodiment of the present application. FIG. 6 is described from the perspective of the interaction between the terminal device, the mobility management network element in the first satellite, the first mobility management network element, and the home user service network element, without constituting any limitation on the execution subject of the present application.

[0155] For example, the terminal device in FIG. 6 can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the terminal device, or a logic module or software capable of realizing all or part of the functions of the terminal device; the mobility management network element (such as the mobility management network element in the first satellite or the first mobility management network element) can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the mobility management network element, or a logic module or software capable of realizing all or part of the functions of the first mobility management network element; and the home user service network element can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the home user service network element, or a logic module or software capable of realizing all or part of the functions of the home user service network element.

[0156] The first mobility management network element can be, for example, the MME deployed in the ground network, such as MME-ground, and the mobility management network element in the first satellite can be, for example, the MME-onboard deployed in the first satellite. The first satellite can be a candidate satellite for providing access services for the terminal device.

[0157] The method shown in FIG. 6 includes S601 to S604, and each step of the method shown in FIG. 6 is described in detail below.

[0158] S601, the home user service network element sends a first key to the first mobility management network element.

[0159] The first key can be any key synchronized between the first mobility management network element and the terminal device. For example, the first key can be a root key between the terminal device and the first mobility management network element, such as K ASME . The derivation mode of K ASME can refer to the description in the foregoing examples, and will not be described again for brevity.

[0160] S602, the first mobility management network element generates a second key for the first satellite according to the first key.

[0161] S603, the first mobility management network element sends the second key to the mobility management network element in the first satellite.

[0162] To ensure the terminal device communicates securely through different satellites, the first mobile management network element generates a second key, such as K ASME , for the first satellite according to a first key, such as K ASME* . That is, K AMSE* = KDF{K ASME}, KDF is a key derivation function (KDF). Then, the first message carrying the second key K ASME* is sent to the mobile management network element in the first satellite, so that the mobile management network element in the first satellite is not aware of the first key, and the communication key is securely isolated between satellites.

[0163] The present application does not limit the derivation algorithm for generating the second key for the first satellite based on the first key, nor the input parameter (such as the first input parameter) for deriving the second key. For example, the first input parameter can include but is not limited to one or more of the following: a satellite identifier corresponding to the first satellite, an identifier of the mobile management network element in the first satellite, a key identifier (such as a key set identifier for access security management entity (KSI ASME )) or a fixed string. For example, the second key can satisfy: K AMSE* = KDF{K ASME , SAT ID}, where SAT ID is the satellite identifier of the first satellite. The key identifier is used to identify the second key generated for the first satellite.

[0164] Optionally, the first mobile management network element can generate the key identifier, such as KSI ASME .

[0165] Optionally, the first mobile management network element can obtain the identifier of the mobile management network element in the first satellite or the satellite identifier of the first satellite by interacting with the mobile management network element in the first satellite. Or the first mobile management network element can determine the satellite identifier of the first satellite and / or the identifier of the mobile management network element in the first satellite according to pre-configured information.

[0166] S604, the mobile management network element in the first satellite and the terminal device generate a NAS key, and protect the messages of the terminal device and the mobile management network element in the first satellite based on the NAS key.

[0167] For the mobility management network element in the first satellite, the NAS key can be generated based on the received second key. The NAS key is used to encrypt and / or protect the integrity of information transmitted between the terminal device and the mobility management network element in the first satellite, such as NAS signaling / data. For example, the NAS key may include an integrity protection key K. NASint and / or encryption key K NASenc Integrity protection key K NASint It can be used to protect the integrity of information transmitted between terminal equipment and mobility management network elements in the first satellite, with encryption key K. NASenc It can be used to encrypt and protect information transmitted between terminal devices and second mobile associated network elements.

[0168] This application does not limit the method of generating the NAS key. For example, you can refer to Appendix A.7 of 3GPP TS33.501, where the input of the NAS key is the root key K. ASME Replace with the first key K ASME* This yields the NAS key in this embodiment.

[0169] For the terminal device, it can deduce the second key and, based on the second key, deduce the NAS key. For example, the terminal device uses the same method as the first mobility management network element, such as the same deduction algorithm and the same input parameters, to deduce the second key from the first key. Further, the terminal device can use the same method as the mobility management network element in the first satellite, such as the same deduction algorithm and the same input parameters, to deduce the NAS key from the second key.

[0170] Optionally, the terminal device may generate a second key for the first satellite before connecting to the first satellite, and generate a NAS key based on the second key during the process of connecting to the mobility management network element in the first satellite.

[0171] For example, when the terminal device determines that it is in S&F mode, it generates the aforementioned NAS key. For example, the terminal device determines that it is in S&F mode based on S&F mode indication information received from a broadcast message from the first satellite, and thus derives the aforementioned NAS key. Optionally, the terminal device derives the aforementioned NAS key based on whether the accessed satellite and the home terrestrial network are in different security domains (or trust domains).

[0172] Based on this, the mobile management network element in the first satellite encrypts the NAS message sent to the terminal device based on the NAS key, and decrypts the NAS message received from the terminal device based on the NAS key; correspondingly, the terminal device encrypts the NAS message sent to the first satellite based on the NAS key, and decrypts the NAS message received from the first satellite based on the NAS key. Thus, the communication transmission between the terminal device and the mobile management network element in the first satellite is realized based on the NAS key protection.

[0173] Further, the terminal device can store the correspondence between the NAS security context and the first satellite, which for example includes the SAT ID and the NAS security context corresponding to each SAT ID. The NAS security context may, for example, include but is not limited to at least one of the following: a NAS encryption key, an encryption algorithm; a NAS integrity protection key, an integrity protection algorithm; and a key identifier. That is, the terminal device can obtain the corresponding NAS key, algorithm, and other security information for protecting the NAS message according to the identifier of the satellite and the corresponding relationship stored locally. When the terminal device leaves the third satellite and accesses the third satellite again, the NAS key can be obtained according to the identifier of the third satellite, and the NAS key is directly used to protect the NAS message between the terminal device and the mobile management entity in the third satellite.

[0174] In this embodiment, in the case of service link connectivity, the terminal device and the mobile management network element of the first satellite can transmit the NAS message protected based on the NAS key.

[0175] For example, in the process of the terminal device accessing the core network, the terminal device and the mobile management network element in the first satellite can perform a NAS security mode command (SMC) process to activate the NAS security, and the related examples will be described below.

[0176] Optionally, in the embodiment of the present application, the process of the terminal device accessing the core network can further include other related steps. For example, before S601, S510 and S520 in FIG. 5 can be further included, before S640, S540 in FIG. 5 and the authentication process (such as the interaction of the user authentication request and the user authentication response) in S550 can be further included, and after S640, S560 in FIG. 5 can be further included. It should be noted that the present application does not limit whether other related steps are performed and the implementation manner of the related steps.

[0177] Based on the above process, after receiving the attach accept message, the terminal device can send an initial access complete message to the mobility management network element in the first satellite, the mobility management network element in the first satellite can forward the initial access complete message to the first mobility management network element, thereby completing the access process. In this embodiment, it can be the initial access process of the terminal device, or it can be the access process after the initial access, such as access caused by service satellite switching. The present application does not limit this.

[0178] Optionally, after the terminal device completes the access process, it can send NAS data protected based on a NAS key, such as a NAS protocol data unit (PDU), to the mobility management network element in the first satellite, and the mobility management network element in the first satellite can verify the integrity of the NAS data based on the NAS key and decrypt the data packet.

[0179] Therefore, in the embodiment of the present application, the first mobility management network element deployed in the ground network generates a second key for the first satellite based on a first key, and sends the second key to the mobility management network element deployed on the first satellite, so that the mobility management network element in the first satellite provides access services for the terminal device based on the second key, wherein the first key is a key for the terminal device received by the first mobility management network element from the home user service network element. Based on this, different keys are provided for different satellites, thereby realizing the security isolation between different satellites and establishing a secure connection between the terminal device and the network.

[0180] FIG. 7 is a flowchart of another communication method provided by an embodiment of the present application. FIG. 7 takes the terminal device, the mobility management network element in the initial satellite, the mobility management network element in the first satellite, the first mobility management network element, and the home user service network element as an example for illustration, without constituting any limitation on the execution subject of the present application.

[0181] It can be understood that the service satellite of the terminal device can be switched in the attach process, such as the initial satellite being the service satellite when the terminal device starts the attach request process, and the first satellite being the service satellite that interacts with the terminal device to complete the authentication and access to the core network. Of course, the service satellite of the terminal device can not be switched in the attach process, in which case the first satellite and the initial satellite can be the same satellite, that is, the mobility management network element in the first satellite and the mobility management network element in the initial satellite are the same network element.

[0182] The embodiment can include part or all of the steps in the method shown in FIG. 7.

[0183] Referring to S701 in FIG. 7, the mobile management network element in the initial satellite can send an attach request message to the first mobile management network element. The attach request message is used to indicate that the terminal device requests to access the core network. The information carried by the attach request message can include, but is not limited to, at least one of the following: the identity (such as IMSI) of the terminal device, S&F capability information, or security capability information. The mobile management network element in the initial satellite can also send the identity of the network selected by the terminal device, such as the PLMN ID, to the first mobile management network element.

[0184] The information carried by the attach request message can be obtained through interaction between the mobile management network element in the initial satellite and the terminal device. For example, before the mobile management network element in the initial satellite sends the attach request message to the first mobile management network element, the terminal device can send a first attach request to the mobile management network element in the initial satellite, and the mobile management network element in the initial satellite sends a first attach response to the terminal device in response to the first attach request. The specific implementation of S510 and S520 in FIG. 5 can be referred to, and will not be repeated here for brevity.

[0185] The above S701 is executed in the case of feeder link connectivity. If the feeder link is not connected, the mobile management network element in the initial satellite stores the information (such as at least one of the IMSI of the terminal device, the S&F capability information, or the security capability information), and waits to send when the feeder link is connected.

[0186] Referring to S702 in FIG. 7, the first mobile management network element can send an authentication data request to the home user service network element.

[0187] For example, in the case of determining that the terminal device needs to be authenticated according to the attach request message, the authentication data request is sent to the home user service network element, and the authentication data request includes the identity of the terminal device, such as the IMSI. The authentication data request can also include the identity of the service network, such as the PLMN ID.

[0188] Referring to S703 in FIG. 7, the home user service network element can send an authentication data response to the first mobile management network element. The authentication data response includes an initial authentication vector for authenticating the terminal device, and the initial authentication vector includes RAND, AUTN, XRES, and the first key, such as K ASME It can be understood that in S703, the home user service network element sends the initial authentication vector to the first mobile management network element, that is, the first key is sent to the first mobile management network element.

[0189] In the first implementation, the authentication data request is used to request at least one authentication vector, such as an AV. In this case, the authentication data response carries the at least one authentication vector. Further, the first mobile management network element also sends an update location request to the home user service network element to obtain the subscription data of the terminal device. At this time, the bi-directional authentication procedure is not performed between the network and the terminal device.

[0190] In the second and third implementations, the authentication data request further includes indication information related to the S&F operation, and the authentication data response further includes subscription data related to the S&F operation.

[0191] In the second implementation, the authentication data request is used to request at least one authentication vector and the subscription data of the terminal device. In this case, the authentication data request can carry first indication information indicating the subscription data of the terminal device. Correspondingly, the authentication data response carries the at least one authentication vector and the subscription data.

[0192] Optionally, the first indication information can be referred to as S&F indication, which is carried in the authentication data request in the case that the terminal device has S&F capability.

[0193] Optionally, the home user service network element obtains the subscription data of the terminal device based on the first indication information, and includes the subscription data in the authentication data response according to the subscription data, when the terminal device is authorized to use the S&F satellite operation. The subscription data carried in the authentication data response can be part or all of the subscription data of the terminal device obtained by the home user service network element.

[0194] In the third implementation, the authentication data request can implicitly indicate the obtaining of the subscription data through second indication information. In one possible example of the third implementation, the second indication information indicates the satellite identifier of a service satellite (such as a first satellite), in which case the satellite identifier can implicitly indicate the obtaining of the subscription data. In another possible example of the third implementation, the second indication information indicates the number N (an integer greater than 1) of authentication vectors, in which case the number of authentication vectors is used to implicitly indicate the obtaining of the subscription data.

[0195] It can be understood that, in the above third implementation, if the second indication information indicates the satellite identifier of a service satellite, the home user service network element can also generate a first key based on the satellite identifier, which will be described in detail below. In the above third implementation, if the second indication information indicates the number of authentication vectors, the home user service network element can generate N authentication vectors according to the indication of the second indication information, and obtain the subscription data.

[0196] The second implementation manner and the third implementation manner can be combined, for example, the first indication information indicates to acquire the subscription data, and the second indication information indicates the satellite identifier and / or the number of authentication vectors, that is, the second indication information can implicitly indicate the subscription data.

[0197] Based on the second implementation manner or the third implementation manner, the authentication data request simultaneously indicates to acquire the authentication vectors and the subscription data, the number of interactions between the first mobile management network element and the home user service network element is reduced, and the communication efficiency is improved.

[0198] It should be understood that the number of authentication vectors is not limited by the embodiments of the present application. As mentioned above, each authentication vector can include RAND, AUTN, XRES and K ASME . That is, each authentication vector in the authentication data response sent by the home user service network element to the first mobile management network element can include the root key between the terminal device and the first mobile management network element, such as K ASME .

[0199] Referring to S704 in FIG. 7, the first mobile management network element derives the authentication vectors.

[0200] Optionally, the first mobile management network element can derive a second key based on the first key in the authentication vector, and then form a new authentication vector by combining the second key with other elements in the authentication information, such as RAND, AUTN and XRES. The new authentication vector can be referred to as a star authentication vector (AV) for example.

[0201] In an implementation, when the authentication data response sent by the home user service network element to the first mobile management network element includes a plurality of initial authentication vectors, the first mobile management network element can determine one or more initial authentication vectors from the plurality of initial authentication vectors, and generate a new authentication vector for each initial authentication vector, for example, derive a second key K ASME from the first key K ASME* in the initial authentication vector, and then form a new authentication vector by combining the second key K ASME* and other elements in the authentication vector, which is referred to as a derived authentication vector.

[0202] Optionally, the first mobile management network element can determine one or more initial authentication vectors with the smallest SQN from the plurality of initial authentication vectors to derive the second key.

[0203] Referring to S705 in FIG. 7, the first mobile management network element can send the derived authentication vector to the mobile management network element in the first satellite. It can be understood that the first mobile management network element sends the derived authentication vector to the mobile management network element in the first satellite, that is, the second key is sent to the mobile management network element in the first satellite.

[0204] For example, the first mobile management network element can first determine the serving satellite of the terminal device, and send the first message to the first satellite when the first satellite is determined as the serving satellite of the terminal device and the feeder link between the first mobile management network element and the first satellite is available. For example, the first mobile management network element can determine the serving satellite of the terminal device according to the ephemeris information. The ephemeris information has been described in the foregoing examples, and will not be described again for the sake of brevity. Optionally, the serving satellite of the terminal device is determined by the first mobile management network element according to the information sent by the initial satellite, for example, the information sent by the initial satellite in step S701 also contains the candidate satellite information of the terminal device. It can be understood that the serving satellite of the terminal device can not have changed, that is, the initial satellite sending the attach request message is still the serving satellite, in which case, the first mobile management network element can send the first message to the initial satellite when the feeder link between the first mobile management network element and the initial satellite is available, and then the initial satellite interacts with the terminal device to perform the related process of accessing the core network by the terminal device.

[0205] Optionally, the new authentication vector derived above can be carried in the first message sent by the first mobile management network element to the mobile management network element in the first satellite, in which case, S705 can be implemented as the first mobile management network element sending the first message to the mobile management network element in the first satellite.

[0206] Optionally, the first message also includes subscription data related to the S&F operation, for example, the first mobile management network element can obtain the subscription data related to the S&F operation from the authentication data response.

[0207] Optionally, the first message can also include a key identifier, such as KSI ASME . The key identifier is used to indicate the second key.

[0208] Optionally, the first mobile management network element can generate a GUTI, and the first message can carry the GUTI.

[0209] It can be understood that the first mobile management network element and the mobile management network element in the first satellite can belong to the same or different security domains (or trust domains), for example, the first mobile management network element and the mobile management network element in the first satellite belong to the same operator, and thus are considered to belong to the same security domain (or trust domain). Of course, the definition of the security domain (or trust domain) is not limited in the present application, for example, the security domain or trust domain can also be defined based on encryption algorithms, access control, etc. In order to reduce the processing complexity, the first mobile management network element can derive the second key, or in other words, derive the new authentication vector, when the first mobile management network element and the mobile management network element in the first satellite belong to different security domains (or trust domains).

[0210] In this embodiment, the first mobile management network element performs S704 and S705 when the feeder link is connected, or performs S704 first and then performs S705 after the feeder link is connected when the feeder link is not connected.

[0211] Further, the mobile management network element in the first satellite receives the derived authentication vector, generates the NAS key based on the second key therein, and the terminal device derives the second key based on the same derivation manner as the first mobile management network element, and then derives the NAS key based on the same derivation manner as the mobile management network element in the first satellite, and then protects the message based on the NAS key to realize secure communication.

[0212] For example, in the process that the terminal device accesses the core network by interacting with the first satellite, steps S706 to S709 shown in FIG. 7 can also be included.

[0213] In S706, the mobile management network element in the first satellite generates the NAS key based on the second key.

[0214] In S707, the mobile management network element in the first satellite sends the first NAS message protected based on the NAS key to the terminal device.

[0215] The first NAS message is used to instruct the terminal device to establish a secure connection. For example, the first NAS message can be the security mode command in the foregoing example.

[0216] Optionally, the first NAS message includes the NAS integrity protection algorithm and the NAS encryption algorithm.

[0217] Optionally, in this embodiment, the first NAS message can also include a key identifier (such as KSI ASME ) and / or an identifier of the mobile management network element of the first satellite. Specifically, the first NAS message can include an encryption key set identifier (eKSI), which can be set as the value of the key identifier (such as KSI ASME ) or generated by the mobile management network element of the first satellite.

[0218] Optionally, the first NAS message can include a message authentication code (MAC), such as NAS-MAC.

[0219] S708, the terminal device generates the NAS key.

[0220] For example, the terminal device can receive a broadcast message sent by a base station in the first satellite, and the broadcast message comprises the satellite identifier of the first satellite. For example, the terminal device can receive the satellite identifier from the base station in a process of establishing an RRC connection based on S410 to S430 in the embodiment shown in FIG. 4. For example, the terminal device can receive the broadcast message from the base station in a cell search and selection process, and thereby obtain the satellite identifier. ASME ) and / or the identifier of the mobile management network element in the first satellite can be used as the input parameter for the terminal device to derive the second key.

[0221] For example, the terminal device can receive the satellite identifier from the base station in a process of establishing an RRC connection based on S410 to S430 in the embodiment shown in FIG. 4. For example, the terminal device can receive the broadcast message from the base station in a cell search and selection process, and thereby obtain the satellite identifier.

[0222] For example, the terminal device can derive the NAS integrity protection key from the second key based on the NAS integrity protection algorithm indicated in the first NAS message, and derive the NAS encryption key from the second key based on the NAS encryption algorithm indicated in the first NAS message.

[0223] Accordingly, the terminal device can decode the first NAS message based on the NAS encryption key and the NAS algorithm, and verify the integrity of the first NAS message based on the NAS integrity protection key and the NAS integrity protection algorithm. Thus, in a case where the integrity verification is passed, the terminal device establishes a secure connection based on the indication in the first NAS message.

[0224] In an implementation manner, the terminal device can perform the following S709 in a case where the integrity verification is passed.

[0225] S709, the terminal device sends a second NAS message protected based on a NAS key to the mobile management network element in the first satellite.

[0226] For example, the second NAS message can comprise an indication of successful establishment of the secure connection, or an indication of failure of establishment of the secure connection. For example, the second NAS message can be the security mode response in the foregoing example, and the security mode response can refer to the description in the foregoing example, which is not repeated here for brevity.

[0227] The mobile management network element in the first satellite can decode the second NAS message and perform integrity verification on the second NAS message based on the NAS key, so that the security establishment process and the authentication process are completed based on the second NAS message when the integrity verification is passed.

[0228] It can be understood that the process of the terminal device accessing the core network in the embodiments of the present application can further include other related steps. For example, before S701, S510 and S520 in FIG. 5 can be further included, such as that the terminal device sends a first attach request to the mobile management network element in the initial satellite, and the mobile management network element in the initial satellite sends a first attach response to the terminal device; before S706, S540 in FIG. 5 can be further included, such as that the terminal device sends a second attach request to the mobile management network element in the first satellite, and the authentication process in S550, such as that the mobile management network element in the first satellite sends a user authentication request to the terminal device, and the terminal device sends a user authentication response to the mobile management network element in the first satellite; after S709, S560 in FIG. 5 can be further included, such as that the mobile management network element of the first satellite sends a second attach response to the terminal device. It should be noted that the present application does not limit whether other related steps are performed and the implementation manner of the related steps.

[0229] Further optionally, the terminal device stores the correspondence between the NAS security context and the first satellite, such as SAT ID, NAS security context (such as NAS encryption key, encryption algorithm, integrity protection key, integrity protection algorithm, key identifier, etc.), that is, the terminal device can obtain the corresponding NAS key, algorithm, etc. for protecting the security information of the NAS message according to the identifier of the satellite and the corresponding relationship stored locally. When the terminal device accesses the third satellite again after leaving the third satellite, the NAS key can be obtained according to the identifier of the third satellite, and the NAS key is directly used to protect the NAS message between the terminal device and the mobile management entity in the third satellite.

[0230] As mentioned above, the IMSI of the terminal device can be carried in the first attach request, sent by the terminal device to the mobility management network element in the initial satellite, and sent by the mobility management network element in the initial satellite to the first mobility management network element through the attach request message, and then carried by the first mobility management network element in the first message to the mobility management network element in the first satellite. This way exposes the user permanent identity multiple times in the air interface, which brings risks to the security of user information. Based on this, in some embodiments, the mobility management network element in the initial satellite can allocate a temporary user identifier to the terminal device, for example, the mobility management network element in the initial satellite can carry the temporary user identifier through the first attach response, send the temporary user identifier to the terminal device, and carry the temporary user identifier in the attach request message sent by the mobility management network element in the initial satellite to the first mobility management network element, and carry the temporary user identifier in the first message sent by the first mobility management network element to the mobility management network element in the first satellite. Further, the terminal device carries the temporary user identifier obtained from the first attach response in the second attach request and sends it to the mobility management network element in the first satellite, thereby reducing the number of times the user permanent identity is exposed in the air interface. In this case, the mobility management network element in the first satellite can obtain the local authentication vector according to the temporary identifier.

[0231] Other elements in the derived authentication vector, such as RAND, AUTN, and XRES, can be used to implement a user authentication process, in which RAND, AUTN, and XRES in the derived authentication vector can be used. For example, the user authentication request can carry RAND and AUTN. It should be understood that if the mobility management network element of the first satellite receives multiple authentication vectors sent by the first mobility management network element, the mobility management network element of the first satellite can determine an authentication vector from the multiple authentication vectors, such as the authentication vector with the smallest SQN, and then carry RAND and AUTN in the authentication vector in the user authentication request.

[0232] As mentioned above, the second key can be derived based on the first input parameter and the first key. When the first input parameter includes a key identifier (such as KSI ASME ), the user authentication request can carry the key identifier (such as KSI ASME ) to synchronize the key identifier (such as KSI ASME ) with the terminal device, so as to facilitate the terminal device to derive the key. In some embodiments, the above-mentioned key identifier (such as KSI ASME ) can be indicated by the first mobility management network element, such as being carried in the first message sent by the first mobility management network element. In other embodiments, the mobility management network element in the first satellite can generate the key identifier (such as KSI ASME ).

[0233] The implementation of the authentication procedure can refer to S551 and S552 in the foregoing embodiments, and details are not described herein for simplicity.

[0234] Optionally, the second attach response can carry a GUTI to allocate the GUTI to the terminal device. The GUTI can be obtained by the mobile management network element in the first satellite from the first message of the first mobile management network element, or the mobile management network element in the first satellite can generate the GUTI, for example, the mobile management network element in the first satellite can generate the GUTI according to the identifier of the first mobile management network element.

[0235] The deduction of the second key by the first mobile management network element is only one possible example, and in another embodiment, the home user service network element sends the first key in the authentication data response to the first mobile management network element, that is, the home user service network element can deduce the second key based on the first key in the authentication vector, and then carries the deduced new authentication vector, such as the on-board AV, in the authentication data response and sends it to the first mobile management network element. The implementation of the home user service network element to deduce the second key is similar to that of the first mobile management network element to deduce the second key, and details are not described herein for simplicity.

[0236] Optionally, when the home user service network element deduces the second key, the authentication data request sent by the first mobile management network element to the home user service network element can carry the satellite identifier of the first satellite if the satellite identifier of the first satellite is used as an input parameter.

[0237] Optionally, when the home user service network element deduces the first key, the authentication data request sent by the first mobile management network element to the home user service network element can carry the key identifier (such as KSI ASME ) if the key identifier (such as KSI ASME ) is used as an input parameter.

[0238] FIG. 8 is a flow diagram of another communication method according to an embodiment of the present application. FIG. 8 is described from the perspective of the interaction between the terminal device, the mobile management network element in the first satellite, the mobile management network element in the second satellite, the first mobile management network element, and the home user service network element, and does not constitute any limitation on the execution subject of the present application.

[0239] To improve the success rate of terminal device accessing the core network or reduce the access delay, the first mobile management network element can send the authentication vector and the subscription data to multiple candidate serving satellites of the terminal device at the same time, so that one of the satellites (such as the second satellite) can interact with the terminal device to complete the terminal device accessing the core network. Based on this, the first satellite and the second satellite in FIG. 8 are different candidate satellites. The first satellite can be the same satellite as the initial satellite in the foregoing example or can be a different satellite, and the second satellite can be the same satellite as the initial satellite in the foregoing example or can be a different satellite, which is not limited in the present application. FIG. 8 only takes the first mobile management network element sending the authentication information and the subscription data to the first satellite and the second satellite as an example for description, but it should be understood that when the first mobile management network element sends the authentication vector and the subscription data to more satellites, the implementation mode of the first satellite and the second satellite can be referred to for execution.

[0240] It should also be understood that the present embodiment can be implemented in combination with any of the embodiments shown in FIG. 6 or FIG. 7, and FIG. 8 only takes the implementation of the present embodiment based on the embodiment shown in FIG. 7 as an example for description.

[0241] Referring to FIG. 8, the method can include the following S801 to S806.

[0242] S801, the first mobile management network element sends an authentication data request to the home user service network element;

[0243] S802, the home user service network element sends an authentication data response to the first mobile management network element;

[0244] S803-1, the first mobile management network element derives an authentication vector for the first satellite;

[0245] S804-1, the first mobile management network element sends the authentication vector derived for the first satellite to the mobile management network element of the first satellite;

[0246] S803-2, the first mobile management network element derives an authentication vector for the second satellite;

[0247] S804-2, the first mobile management network element sends the authentication vector derived for the second satellite to the mobile management network element of the second satellite;

[0248] S805, the terminal device and the mobile management network element of the second satellite generate a NAS key and protect the messages between the terminal device and the mobile management network element of the second satellite based on the NAS key;

[0249] S806, the mobile management network element of the second satellite sends third indication information to the first mobile management network element, and the third indication information indicates that the authentication for the terminal device is successful.

[0250] For S801 and S802 above:

[0251] In the first implementation, the authentication data request is used to request a plurality of authentication vectors. In this case, the authentication data response carries the plurality of authentication vectors. Further, the first mobile management network element sends an update location request to the home user service network element to update the location of the terminal device to obtain the subscription data of the terminal device.

[0252] In the second implementation, the authentication data request is used to request a plurality of authentication vectors and the subscription data of the terminal device. In this case, the authentication data request can carry first indication information indicating the subscription data of the terminal device. Correspondingly, the response message of the authentication data request carries the plurality of authentication vectors and the subscription data.

[0253] The manner in which the home user service network element obtains the subscription data of the terminal device based on the first indication information and the manner in which the home user service network element obtains the subscription data of the terminal device based on the implicit indication of the second indication information have been described in the foregoing examples, and will not be described again for brevity.

[0254] The plurality of authentication vectors can include one or more authentication vectors corresponding to each candidate serving satellite of the terminal device, such as the first satellite and the second satellite.

[0255] As an example, the number of authentication vectors carried in the authentication data response can be determined based on the number of candidate serving satellites. For example, the authentication data request can also carry information indicating the number of authentication vectors, and the home user service network element can send the authentication vectors and the subscription data to the corresponding data through the authentication data response. As another example, the number of authentication vectors carried in the authentication data response can be preset, such as being agreed in a protocol or being preconfigured. In this case, part or all of the candidate serving satellites can be selected from the number of authentication vectors, and the authentication vectors and the subscription data are sent to the selected candidate serving satellites. The authentication vectors are described in the foregoing examples, and will not be described again for brevity.

[0256] In the above steps, the execution order of S803-1, S803-2, S804-1, and S804-2 is not limited.

[0257] In S803-1 to S804-2, in order to ensure that the terminal device communicates securely through different satellites, the first mobile management network element derives a second key for the first satellite according to the first key in the authentication vector corresponding to the first satellite, and then sends the derived authentication vector including the second key to the mobile management network element in the first satellite; the first mobile management network element derives a second key for the second satellite according to the first key in the authentication vector corresponding to the second satellite, and then sends the derived authentication vector including the second key to the mobile management network element in the second satellite. The mobile management network elements on each satellite are all unaware of the root key, and the root key is securely isolated between satellites.

[0258] The derivation method of the second key has been described in the foregoing examples, and will not be repeated here for brevity. It should be noted that the second key for the first satellite and the second key for the second satellite are derived based on the root key in different authentication vectors. For example, the second key for the first satellite is derived based on the first key in the first AV, and the first on-satellite AV including the second key is obtained by replacing the first key in the first AV with the second key. The second key for the second satellite is derived based on the first key in the second AV, and the second on-satellite AV including the second key is obtained by replacing the first key in the second AV with the second key.

[0259] In order to achieve secure isolation between satellites, the second key for the first satellite and the second key for the second satellite are different. For example, the second key for the first satellite and the second key for the second satellite can be determined based on different types of input parameters. For example, the second key for the first satellite is derived based on the first key, and the second key for the second satellite is derived based on the satellite identifier of the second satellite and the first key. For another example, the input parameters of the second key for the first satellite and the second key for the second satellite have different parameter values. For example, the second key for the first satellite is derived based on the satellite identifier of the first satellite and the first key, and the second key for the second satellite is derived based on the satellite identifier of the second satellite and the first key.

[0260] Optionally, one of the second key for the first satellite and the second key for the second satellite can be the first key, such as the root key K ASME For example, the second key of the second satellite can be the first key, and the second key for the first satellite can be a second key derived based on the first key. Correspondingly, the authentication vector for the second satellite can be the initial authentication vector.

[0261] Optionally, the first mobile management network element can send one or more second keys corresponding to the first satellite to the mobile management network element in the first satellite, or in other words, the first mobile management network element can send one or more authentication vectors corresponding to the first satellite to the mobile management network element in the first satellite, each authentication vector including a second key.

[0262] Optionally, the first mobile management network element can send one or more second keys corresponding to the second satellite to the mobile management network element in the second satellite, or in other words, the first mobile management network element can send one or more authentication vectors corresponding to the second satellite to the mobile management network element in the second satellite, each authentication vector including a second key.

[0263] Optionally, the authentication vector derived for the first satellite can be carried in the second message sent by the first mobile management network element to the mobile management network element in the first satellite; the authentication vector derived for the second satellite can be carried in the third message sent by the first mobile management network element to the mobile management network element in the second satellite.

[0264] Optionally, the second message can carry fourth indication information indicating the identity of each authentication vector corresponding to the first satellite, such as AV ID.

[0265] Optionally, the third message can carry fifth indication information indicating the identity of each authentication vector corresponding to the second satellite, such as AV ID.

[0266] Optionally, the first mobile management network element can store the identity of the authentication vector corresponding to each candidate serving satellite.

[0267] Optionally, the first mobile management network element can generate a key identifier, such as KSI ASME The key identifier can be carried in the second message and the third message.

[0268] It can be understood that the second message can also include the related information in the first message in the embodiment shown in Figure 7, such as the subscription data related to the S&F operation, and the third message can also include the related information in the first message in the embodiment shown in Figure 7, such as the subscription data related to the S&F operation. Correspondingly, the authentication data request can also include the related information in the authentication data request in the embodiment shown in Figure 7, such as the indication information related to the S&F operation.

[0269] In an implementation, the first mobile management network element can determine one or more authentication vectors corresponding to each candidate serving satellite from the multiple authentication vectors carried by the authentication data response, and generate a new authentication vector for each of the determined one or more authentication vectors. Optionally, the first mobile management network element can determine one or more authentication vectors with the minimum SQN from the multiple authentication vectors corresponding to the first satellite for derivation of the second key; and determine one or more authentication vectors with the minimum SQN from the multiple authentication vectors corresponding to the second satellite for derivation of the second key.

[0270] The first mobile management network element can first determine the candidate serving satellites for the terminal device, and send the second message to the first satellite and the third message to the second satellite when the first satellite and the second satellite are determined as the candidate serving satellites for the terminal device. For example, the first mobile management network element can determine the candidate serving satellites for the terminal device according to the ephemeris information. The ephemeris information has been described in the foregoing examples, and thus will not be described again for the sake of brevity.

[0271] In the embodiment, the first mobile management network element can send the second message to the mobile management network element in the first satellite when the feeder link between the first mobile management network element and the first satellite is connected. The first mobile management network element can send the third message to the mobile management network element in the second satellite when the feeder link between the first mobile management network element and the second satellite is connected.

[0272] In the embodiment, the implementation of S805 is similar to S604 in FIG. 6 or S707 to S709 in FIG. 7, and thus will not be described again for the sake of brevity.

[0273] Further, the terminal device can interact with one of the candidate serving satellites, such as the second satellite, to complete the initial attach procedure.

[0274] In S806, the mobile management network element in the second satellite can send sixth indication information to the first mobile management network element, where the sixth indication information indicates that the authentication for the terminal device is successful.

[0275] Optionally, the sixth indication information can be included in the fourth message sent by the mobile management network element in the second satellite to the first mobile management network element.

[0276] Optionally, the fourth message can further include the context of the terminal device, which can be referred to as a security context. It can be understood that the security context is information required for message decryption and / or integrity verification, for example, can include the NAS key, and optionally, can further include the first key, the security capability of the terminal device, the uplink and downlink NAS COUNT value, and the like.

[0277] For example, the mobile management network element in the second satellite can send the fourth message to the first mobile management network element when the feeder link is connected. In this case, the mobile management network element in the second satellite can store the context of the terminal device. For the mobile management network element in the second satellite, storing the context of the terminal device can also enable the terminal device to attach to the mobile management network element in the second satellite again, and enable the terminal device to implement subsequent access services by using the stored NAS key.

[0278] FIGS. 9a and 9b are flow diagrams of another communication method provided by the embodiments of the present application. FIGS. 9a and 9b are described from the perspective of the interaction between the terminal device, the mobile management network element in the first satellite, the mobile management network element in the second satellite, the first mobile management network element, and the home user service network element, and do not constitute any limitation on the execution subject of the present application.

[0279] The second satellite can be a satellite that provides access services for the terminal device, and the first satellite can be a satellite that provides access services for the terminal device after the service satellite of the terminal device is switched. It can be understood that the access services provided by the second satellite for the terminal device can be initial access, but the present application does not make any limitation thereon. In the case where the second satellite provides initial access services for the terminal device, the first satellite can be a satellite that provides subsequent access services for the terminal device after the terminal device completes the initial access. The first satellite and the second satellite can be different satellites, or the first satellite can be the same as the second satellite. For example, the terminal device attaches to the mobile management network element in the second satellite again after leaving the second satellite, and the second satellite in the embodiment can be replaced with the first satellite in the embodiment shown in FIG. 6. The first satellite can be the same as or different from the first satellite in the foregoing example, and the first satellite can be the same as or different from the initial satellite in the foregoing example, and the present application does not make any limitation thereon.

[0280] It should also be understood that the embodiments can be implemented in combination with any of the embodiments shown in FIGS. 6 to 8.

[0281] Referring to FIG. 9a, the method can include the following S901a to S903a.

[0282] S901a, the mobile management network element in the second satellite sends sixth indication information to the first mobile management network element, indicating that the authentication for the terminal device is successful;

[0283] S902a, the first mobile management network element sends a NAS key for the first satellite to the mobile management network element in the first satellite;

[0284] S903a, the terminal device and the mobile management network element in the first satellite protect the messages between the terminal device and the mobile management network element in the second satellite based on the NAS key.

[0285] S901a can be seen in S806 in the foregoing examples, and will not be described again for brevity.

[0286] In S902a, the first mobile management network element can send, to the management network element in the first satellite, the NAS key for the first satellite in response to the sixth indication information.

[0287] For example, the first mobile management network element can determine the third key according to the second input parameter and the first key, the third key can be understood as a second key generated for the first satellite, and further, the first mobile management network element generates the NAS key for the first satellite according to the third key. In some embodiments, the second input parameter can include, but is not limited to, at least one of the following: a satellite identifier corresponding to the first satellite, an identifier of the mobile management network element in the first satellite, a key identifier such as KSI ASME , or a fixed string. In another embodiment, the third key is the same as the second key generated for the second satellite, in which case the second input parameter can include, but is not limited to, at least one of the following: a satellite identifier corresponding to the second satellite, an identifier of the mobile management network element in the second satellite, a key identifier such as KSI ASME , or a fixed string.

[0288] It should be noted that the first mobile management network element deduces the third key in a similar manner to deducing the second key. In order to achieve security isolation between satellites, the third key and the second key can be different, and the second input parameter for deducing the third key and the first input parameter for deducing the second key should be different. In some embodiments, the first input parameter and the second input parameter can be different in parameter type, for example, the second input parameter can include a satellite identifier such as a satellite identifier of the first satellite, and the first input parameter does not include a satellite identifier, and for example, the first input parameter includes a fixed string, and the second input parameter includes a key identifier such as KSI ASME . In another embodiment, the first input parameter and the second input parameter can be different in parameter value, for example, the first input parameter and the second input parameter both include a satellite identifier, the first input parameter includes a satellite identifier of the first satellite, and the second input parameter includes a satellite identifier of the first satellite.

[0289] Optionally, the first mobile management network element can obtain the second key for the second satellite by obtaining the context of the terminal device, and then determine the NAS key for the first satellite based on the second key for the second satellite.

[0290] The fourth message carrying the sixth indication information can also carry the context of the terminal device. The first mobile management network element can obtain the context of the terminal device through the fourth message, or the first mobile management network element can update the context of the terminal device stored in the ground network based on the context carried in the fourth message to obtain the context of the terminal device. The first mobile management network element can send the context of the terminal device to the mobile management network element in the first satellite, and the NAS key for the first satellite can be carried in the sent context. Thus, it is convenient to perform secure transmission after the terminal device is connected to the mobile management network element in the second satellite.

[0291] For example, in the case of the same satellite for the first satellite and the second satellite, the NAS key for the first satellite sent by the first mobile management network element to the mobile management network element in the first satellite, i.e., the NAS key for the second satellite sent by the first mobile management network element to the mobile management network element in the second satellite, can be obtained by the first mobile management network element based on the following possible implementation manners:

[0292] Implementation manner one, the NAS key is obtained from the fourth message sent by the mobile management network element in the second satellite.

[0293] Implementation manner two, the first mobile management network element generates the NAS key based on a second key generated for the second satellite. The second key can be derived by the first mobile management network element in S602 described above, and the manner in which the first mobile management network element generates the NAS key based on the second key can refer to the manner of generating the NAS key in the foregoing examples, which will not be described again for brevity.

[0294] Optionally, the first mobile management network element can derive a new second key for the second satellite based on the first key, and then generate the NAS key based on the new second key. For example, the input parameters for deriving the new second key can be different from the input parameters for deriving the second key in S602 described above, for example, the satellite identifier of the second satellite is used as an input parameter when deriving the new second key, and the input parameters for deriving the first key in S602 described above can not include the satellite identifier.

[0295] Implementation manner three, the NAS key generated for the second satellite includes a terminal device verification code and a network device verification code, which can be determined based on MAC, such as NAS-MAC. The MAC can be the same as or different from the MAC carried in the first NAS message described above, which is not limited in the present application.

[0296] The first mobile management network element can generate the terminal device verification code and the network device verification code according to an agreed manner. For example, the MAC includes M bits, the terminal device verification code can be the first X bits, and the network verification code can be the last M-X bits, or the network verification code can be the first X bits, and the terminal device verification code can be the last M-X bits. For example, in a 32-bit MAC, the first 16 bits are signed as the terminal device verification code, and the last 16 bits are signed as the network verification code.

[0297] It can be understood that when the NAS key for the second satellite includes the terminal device verification code and the network verification code, the terminal device verification code and the network verification code used for verifying the integrity of the transmission information can include that the NAS message sent by the terminal device to the mobile management network element in the second satellite can carry the terminal device verification code, the mobile management network element in the second satellite performs integrity check on the NAS message based on the terminal device verification code, the NAS message sent by the mobile management network element in the second satellite to the terminal device can carry the network verification code, and the terminal device performs integrity check on the NAS message based on the network verification code, so as to ensure that the identities of the two communication parties are legal and the transmission information is complete.

[0298] The application does not limit the acquisition manner of the MAC. For example, referring to FIG. 10, the MAC can be generated based on an algorithm related to an integrity key Key, a network identity and authentication information (NIA), wherein the input parameters can include part or all of the following: a message, a bearer identifier (BEARER), a transmission direction, or a counter value (COUNT) related to a specific bearer and direction. The message can be a satellite identity; the transmission direction indicates whether it is uplink transmission or downlink transmission; the BEARER is an identifier of a dedicated radio bearer (DRB), and the value allocation manner is defined by 3GPP TS 38.323; and the COUNT is used to prevent replay attacks and ensure the order of transmission data packets.

[0299] Further, the terminal device can store a correspondence relationship between the NAS security context and the first satellite, which for example includes a SAT ID and a NAS security context corresponding to each SAT ID. The NAS context may, for example, include at least one of the following: a NAS encryption key, an encryption algorithm; a NAS integrity protection key, an integrity protection algorithm; a key identifier, and the like. That is, the terminal device can obtain the corresponding NAS key, algorithm, and the like for protecting the security of the NAS message according to the identifier of the satellite and the locally stored correspondence relationship. When the terminal device accesses the first satellite again after leaving the first satellite, the NAS key can be obtained according to the identifier of the first satellite, and the NAS message between the terminal device and the mobility management entity in the first satellite is directly protected by using the NAS key.

[0300] S903a is similar to S604 in the embodiment shown in FIG. 6, and will not be described again for brevity.

[0301] Referring to FIG. 9b, the method can include the following S901b-S903b.

[0302] S901b, the mobility management network element in the second satellite sends sixth indication information to the first mobility management network element, indicating that the authentication for the terminal device is successful;

[0303] S902b, the first mobility management network element sends a second key for the first satellite to the mobility management network element in the first satellite;

[0304] S903b-1, the mobility management network element in the first satellite sends a first NAS message protected based on a NAS key to the terminal device;

[0305] S903b-2, the terminal device generates a second key for the third satellite;

[0306] S903b-3, the terminal device generates a NAS key according to the second key;

[0307] S903b-4, the terminal device sends a second NAS message protected based on a NAS key to the mobility management network element in the first satellite.

[0308] The difference between FIG. 9b and FIG. 9a described above is that after the second satellite provides access services for the terminal device, the first mobility management network element can synchronize the second key for the second satellite to the first satellite, and then the terminal device and the mobility management network element in the first satellite can activate the NAS key of the first satellite by performing the NAS SMC process.

[0309] For example, in the process that the terminal device attaches to the mobility management network element in the first satellite, the mobility management network element in the first satellite can derive the NAS key based on the received second key, protect the first NAS message based on the NAS key, and then send the first NAS message protected based on the NAS key to the terminal device; the terminal device can generate the second key according to the first key, derive the NAS key according to the second key, verify the integrity of the first NAS message based on the NAS key, protect the second NAS message based on the NAS key, and finally send the second NAS message protected based on the NAS key to the mobility management network element in the first satellite; the mobility management network element in the first satellite verifies the integrity of the second NAS based on the NAS key.

[0310] In an example, the second key for the first satellite sent by the first mobility management network element to the mobility management network element in the first satellite can be the same as the second key for the second satellite, such as the input parameters used in the process of generating the second key for the first satellite can include but not limited to: the satellite identifier corresponding to the second satellite and / or the identifier of the mobility management network element in the second satellite. Correspondingly, the terminal device derives the second key for the first satellite based on the same algorithm and input parameters, such as the input parameters can include but not limited to: the satellite identifier corresponding to the second satellite and / or the identifier of the mobility management network element in the second satellite.

[0311] In another example, the second key for the first satellite sent by the first mobility management network element to the mobility management network element in the first satellite can be different from the second key for the second satellite, such as the input parameters used in the process of generating the second key for the first satellite can include but not limited to: the satellite identifier corresponding to the first satellite and / or the identifier of the mobility management network element in the first satellite. Correspondingly, the terminal device derives the second key for the first satellite based on the same algorithm and input parameters, such as the input parameters can include but not limited to: the satellite identifier corresponding to the first satellite and / or the identifier of the mobility management network element in the first satellite.

[0312] It should be noted that S903b-1 to S903b-4 in the embodiment are only to illustrate the NAS key used by the first satellite when providing access services subsequently. The NAS SMC process implemented in S903b-1 to S903b-4 can refer to S707 to S709 and related embodiments in the embodiment shown in FIG. 7, and will not be described in detail.

[0313] Further, the terminal device can store a correspondence relationship between the NAS security context and the first satellite, which for example includes the SAT ID and the NAS security context corresponding to each SAT ID. The NAS context may, for example, include at least one of the following: a NAS encryption key, an encryption algorithm; a NAS integrity protection key, an integrity protection algorithm; a key identifier, and the like. That is, the terminal device can obtain the corresponding NAS key, algorithm, and the like for protecting the security information of the NAS message according to the identifier of the satellite and the locally stored correspondence relationship. When the terminal device accesses the first satellite again after leaving the first satellite, the NAS key can be obtained according to the identifier of the first satellite, and the NAS message between the terminal device and the mobility management entity in the first satellite is directly protected using the NAS key.

[0314] It can be understood that S901a in the above FIG. 9a can be performed when the feeder link between the second satellite and the first mobility management network element is connected; S902a can be performed when the feeder link between the first satellite and the first mobility management network element is connected; and S903a can be performed when the service link between the terminal device and the first satellite is connected. S901b in the above FIG. 9b can be performed when the feeder link between the second satellite and the first mobility management network element is connected; S902b can be performed when the feeder link between the first satellite and the first mobility management network element is connected; and S903b-1 to S903b-4 can be performed when the service link between the terminal device and the first satellite is connected.

[0315] In this embodiment, after the service satellite is switched, the first mobility management network element can synchronize the context of the terminal device, such as the NAS key or the second key used to generate the NAS key, to the satellite that subsequently provides the access service, thereby facilitating the terminal device to quickly access after the service satellite is switched.

[0316] In the above S901a or S901b, the sixth indication information sent by the mobility management network element in the second satellite to the first mobility management network element can be carried in the fourth message, that is, the fourth message is sent by the mobility management network element in the second satellite to the first mobility management network element to realize the transmission of the sixth indication information.

[0317] In some embodiments, the fourth message sent by the mobility management network element in the second satellite to the first mobility management network element can further include seventh indication information, which indicates the authentication vector corresponding to the second key generated for the second satellite, such as the identifier of the authentication vector corresponding to the first key, such as the AV ID.

[0318] In the above example, the first mobile management network element determines, based on the seventh indication information, that the corresponding authentication vector is an invalid authentication vector, i.e., an authentication vector that has been used, and deletes the authentication vector. Further, in order to ensure the freshness of the authentication vector, the first mobile management network element can regard, as invalid authentication vectors, authentication vectors that have a local stored SQN less than the SQN of the authentication vector indicated by the seventh indication information, and deletes these invalid authentication vectors.

[0319] In the embodiment, the fourth message is sent by the mobile management network element in the second satellite to the first mobile management network element when the feeder link between the second satellite and the first mobile management network element is in communication.

[0320] FIG. 11 is a schematic flowchart of a communication method according to an embodiment of the present application. FIG. 11 is described from the perspective of the terminal device, the mobile management network element in the first satellite, the first mobile management network element, and the home user service network element interacting with each other, without constituting any limitation on the execution subject of the present application.

[0321] For example, the terminal device in FIG. 11 can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the terminal device, or a logic module or software capable of implementing all or part of the functions of the terminal device; the mobile management network element (such as the mobile management network element in the first satellite or the first mobile management network element) can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the mobile management network element, or a logic module or software capable of implementing all or part of the functions of the first mobile management network element; and the home user service network element can be replaced by a component (such as a chip, a chip system, a processor, etc.) configured in the home user service network element, or a logic module or software capable of implementing all or part of the functions of the home user service network element.

[0322] The embodiment shown in FIG. 11 further includes a second satellite. The second satellite can be another satellite that provides access services for the terminal device, for example, can provide access services for the terminal device when the service satellite of the terminal device is switched from the first satellite to the second satellite.

[0323] The method shown in FIG. 11 includes some or all of S1001 to S1018, and each step of the method shown in FIG. 11 is described in detail below.

[0324] When the service link between the first satellite and the terminal device is in communication, but the feeder link between the EPC is not in communication, the following S1001 to S1003 can be performed.

[0325] In S1001, if the terminal device identifies that the current serving cell supports the S&F mode and the user equipment is allowed to use the S&F mode, the terminal device sends a first attach request to the network (such as a mobility management network element in the first satellite). The request contains the IMSI and S&F capability information.

[0326] In S1002, if the mobility management network element in the first satellite does not have the terminal device context to authenticate the terminal device, the mobility management network element in the first satellite stores the first attach request, or the information (such as the IMSI and S&F capability information) in the first attach request.

[0327] In S1003, the mobility management network element in the first satellite rejects the attachment by sending an attach reject message with an S&F wait timer and a monitoring list to the terminal device.

[0328] When the service link between the first satellite and the terminal device is not connected, but the feeder link between the first satellite and the EPC is connected, the following S1004 to S1008 can be performed.

[0329] In S1004, the mobility management network element in the first satellite sends an attach request message (or called a registration request message) to the first mobility management network element.

[0330] In S1005, the first mobility management network element sends an authentication data request to the home user service network element, which includes the IMSI, SN ID, network type, and S&F indication.

[0331] In S1006, when the home user service network element determines that the terminal device supports the S&F operation, one or more authentication vectors are generated according to the agreement in 3GPP TS33.401 [3], and an authentication data response is sent, which includes one or more authentication vectors and S&F operation related subscription data.

[0332] In S1007, the first mobility management network element determines to provide access services for the user equipment using the first satellite. To prevent multiple satellites from providing access services for the terminal device, the first mobility management network element obtains the key (i.e., the first key) of the first mobility management network element or the key (i.e., the second key for the satellite) of the mobility management network element on other satellites, and stores the first key, such as K ASME , and derives the second key for the first satellite, such as K ASME* , using the first key and the satellite identifier of the first satellite. Optionally, the mobility management network element in the first satellite also allocates the GUTI and KSI ASME .

[0333] In S1008, the first mobile management network element sends a terminal device information notification message to the mobile management network element in the first satellite, which includes IMSI, authentication vectors (such as RAND, AUTN, XRES and K ASME* ), subscription data, GUTI and KSI ASME .

[0334] When the first satellite is in communication with the terminal device via a service link but not in communication with the EPC via a feeder link, the following S1009 to S1016 can be performed.

[0335] In S1009, the terminal device sends a second attach request to the network (such as the mobile management network element in the first satellite), which includes IMSI and S&F capability information.

[0336] In S1010, the mobile management network element in the first satellite determines that it has the authentication vector of the terminal device, and initiates an authentication procedure by sending a user authentication request to the terminal device, which includes RAND, AUTN and KSI ASME .

[0337] In S1011, the terminal device sends a user authentication response containing RES to the mobile management network element in the first satellite.

[0338] In S1012, the mobile management network element in the first satellite derives the NAS key based on the second key, such as K ASME* , according to the provisions of 3GPP TS33.401 [3].

[0339] In S1013, the mobile management network element in the first satellite sends a NAS security mode command that is integrity protected.

[0340] In S1014, the terminal device derives the second key for the first satellite, such as K ASME* , using the same method as the mobile management network element in the first satellite, and derives the NAS key using the same method as the mobile management network element in the first satellite.

[0341] In S1015, the terminal device verifies the NAS security mode command. If the verification is successful, the terminal device should use this security context to initiate NAS integrity protection and encryption / decryption, and send an encrypted and integrity protected NAS security mode complete message to the mobile management network element in the first satellite.

[0342] In S1016, the mobile management network element in the first satellite sends a second attach response to the terminal device, which carries the GUTI received in S1008 above.

[0343] When the service link between the first satellite and the terminal device is not connected, but the feeder link between the first satellite and the EPC is connected, the following S1017 to S1018 can be performed.

[0344] In S1017, the mobile management network element in the first satellite verifies the NAS message and decrypts the protocol data unit (PDU), and sends a terminal device information synchronization (UE info Sync) carrying the data protocol data unit if the data protocol data unit (data PDU) is received from the terminal device.

[0345] In S1018, the first mobile management network element sends a location update indication to the home user service network element, indicating that the terminal device has been successfully authenticated. Further, if the data protocol data unit (data PDU) is received from the mobile management network element in the first satellite, an arbitrary data transmission process is further performed.

[0346] It should be understood that each step in the embodiment shown in FIG. 11 can also be explained in combination with the description in any of the foregoing embodiments, and will not be repeated here for brevity. It should also be understood that each embodiment in the present application can be combined with each other to implement the communication method proposed in the present application without logical conflict.

[0347] FIG. 12 is a schematic block diagram of a communication apparatus according to an embodiment of the present application. The communication apparatus 1100 can correspond to the first mobile management network element, the mobile management network element in any satellite, the home user service network element, or the terminal device in the foregoing method embodiments. As shown in FIG. 12, the apparatus 1100 can include a transceiver module 1110 and a processing module 1120.

[0348] When the communication apparatus 1100 corresponds to the first mobile management network element in the foregoing method embodiments, the processing module 1120 can be configured to generate a second key for the first satellite according to a first key, wherein the first satellite is a candidate satellite for subsequently providing access service for a terminal device; the first key is a key for the terminal device received by the first mobile management network element from a home user service network element; and the transceiver module 1110 can be configured to send the second key to a mobile management network element in the first satellite.

[0349] When the communication apparatus 1100 corresponds to the terminal device in the above method embodiments, the processing module 1120 can be configured to generate, in a process of attaching to a mobility management network element in a first satellite, a second key for the first satellite according to a first key, wherein the first key is a key generated in a process of attaching to a mobility management network element in a second satellite by the terminal device, and generate a non-access stratum (NAS) key according to the second key, wherein the NAS key is used to protect messages between the terminal device and the mobility management network element in the first satellite, and the NAS key comprises a NAS encryption key and a NAS integrity protection key.

[0350] When the communication apparatus 1100 corresponds to the mobility management network element in the first satellite in the above method embodiments, the transceiver 1110 can receive a second key from a first mobility management network element, wherein the second key is generated for a first satellite based on a first key, the first key is a key for a terminal device received by the first mobility management network element from a home user service network element, and the first satellite is a candidate satellite for providing access service for the terminal device in the future, and the processing module 1120 can be configured to generate a NAS key according to the second key, wherein the NAS key is used to protect messages between the terminal device and the mobility management network element in the first satellite, and the NAS key comprises a NAS encryption key and a NAS integrity protection key.

[0351] When the communication apparatus 1100 corresponds to the home user service network element in the above method embodiments, the transceiver 1110 can be configured to receive an authentication data request from a first mobility management network element, wherein the authentication data request comprises an identifier of a terminal device, and send an authentication data response to the first mobility management network element, wherein the authentication data response comprises an initial authentication vector used to authenticate the terminal device, and the initial authentication vector comprises RAND, AUTN, XRES and a first key, wherein the first key is a key for the terminal device received by the first mobility management network element from the home user service network element.

[0352] It should be understood that the specific processes performed by each module have been described in detail in the above method embodiments, and for the sake of brevity, will not be described here.

[0353] The transceiver 1110 in the communication apparatus 1100 can be implemented by a transceiver, for example, can correspond to the transceiver 1220 in the communication apparatus 1200 shown in FIG. 13, and the processing module 1120 in the communication apparatus 1100 can be implemented by at least one processor, for example, can correspond to the processor 1210 in the communication apparatus 1200 shown in FIG. 13.

[0354] When the communication apparatus 1100 is a chip or a chip system configured in a communication device, the transceiver module 1110 in the communication apparatus 1100 can be implemented by an input / output interface, a circuit, or the like, and the processing module 1120 in the communication apparatus 1100 can be implemented by a processor, a microprocessor, an integrated circuit, or the like integrated on the chip or the chip system.

[0355] FIG. 13 is another schematic block diagram of a communication apparatus provided by an embodiment of the present application. As shown in FIG. 13, the communication apparatus 1200 can include a processor 1210. The processor 1210 can be configured to execute the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element, or the terminal device in the above method embodiments.

[0356] In some possible implementation manners, the communication apparatus 1200 can include a transceiver 1220. The transceiver 1220 can communicate with the processor 1210 through an internal connection path. The processor 1210 can control the transceiver 1220 to send and / or receive signals.

[0357] In some possible implementation manners, the communication apparatus 1200 can include a memory 1230. The memory 1230 can communicate with the processor 1210 through an internal connection path. The memory 1230 and the processor 1210 can be integrated together or arranged separately. The memory 1230 can also be a memory outside the apparatus. The memory 1230 is configured to store instructions, and the processor 1210 is configured to execute the instructions stored in the memory 1230 to perform the methods in the above method embodiments.

[0358] It should be understood that the communication apparatus 1200 can correspond to the first mobility management network element, the mobility management network element in any satellite, the home user service network element, or the terminal device in the above method embodiments, and can be configured to perform various steps and / or processes performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element, or the terminal device in the above method embodiments. Optionally, the memory 1230 can include a read-only memory and a random access memory, and provide instructions and data for the processor. A part of the memory can also include a non-volatile random access memory. The memory 1230 can be one separate device, or integrated in the processor 1210. The processor 1210 can be configured to execute the instructions stored in the memory 1230, and when the processor 1210 executes the instructions stored in the memory, the processor 1210 is configured to perform various steps and / or processes of the above method embodiments corresponding to the first mobility management network element, the mobility management network element in any satellite, the home user service network element, or the terminal device.

[0359] The transceiver 1220 can include a transmitter and a receiver. The transceiver 1220 can further include an antenna, and the number of the antenna can be one or more. The processor 1210 and the memory 1230 and the transceiver 1220 can be integrated on different chips. For example, the processor 1210 and the memory 1230 can be integrated on a baseband chip, and the transceiver 1220 can be integrated on a radio frequency chip. The processor 1210 and the memory 1230 and the transceiver 1220 can also be integrated on the same chip. The present application does not make a limitation in this regard.

[0360] Alternatively, the transceiver 1220 can also be a communication interface, such as an input / output interface, a circuit, etc. The transceiver 1220, the processor 1210 and the memory 1230 can be integrated on the same chip, such as a baseband chip.

[0361] The present application also provides a communication apparatus, including at least one processor, the at least one processor is configured to execute a computer program or a logic circuit, so that the processing apparatus executes the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device in the above method embodiments. The above communication apparatus can also include a memory, and the memory is configured to store the above computer program.

[0362] The embodiments of the present application also provide a communication apparatus, including a processor and an input / output interface. The input / output interface is coupled to the processor. The input / output interface is configured to input and / or output information. The information includes at least one of instructions and data. The processor is configured to execute a computer program, so that the processing apparatus executes the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device in the above method embodiments.

[0363] The embodiments of the present application also provide a communication apparatus, including a processor and a memory. The memory is configured to store a computer program, and the processor is configured to call and execute the computer program from the memory, so that the processing apparatus executes the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device in the above method embodiments.

[0364] It should be understood that the processing device described above can be one or more chips. For example, the processing device can be a field programmable gate array (FPGA), can be an application specific integrated circuit (ASIC), can also be a system on chip (SoC), can also be a central processor unit (CPU), can also be a network processor (NP), can also be a digital signal processor (DSP), can also be a micro controller unit (MCU), can also be a programmable logic device (PLD) or other integrated chip.

[0365] In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in the processor or the instructions in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution completion, or executed by hardware and software modules in the processor. The software module can be located in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0366] It should be noted that the processor in the embodiments of the present application can be an integrated circuit chip with a signal processing capability. In the implementation process, the steps of the above method embodiments can be completed by an integrated logic circuit or an instruction in the form of software in the processor. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The disclosed methods, steps and logic block diagrams in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor or the like. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register or other mature storage medium in the art. The storage medium is located in the storage, and the processor reads the information in the storage, and combines the hardware to complete the steps of the above method.

[0367] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM). It should be noted that the memory of the system and method described herein is intended to include but not limited to these and any other suitable types of memory.

[0368] According to the method provided by the embodiments of the present application, the present application further provides a computer program product, which comprises a computer program or a set of instructions, and when the computer program or the set of instructions run on a computer, the computer program or the set of instructions make the computer execute the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device in the above method embodiments.

[0369] According to the method provided by the embodiments of the present application, the present application further provides a computer readable storage medium, which stores a program, and when the program runs on a computer, the program makes the computer execute the method performed by the first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device in the above method embodiments.

[0370] According to the method provided by the embodiments of the present application, the present application further provides a communication system, which can comprise the above-mentioned first mobility management network element, the mobility management network element in any satellite, the home user service network element or the terminal device.

[0371] Those skilled in the art can understand that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software mode depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0372] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the above method embodiments, which will not be described here.

[0373] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: A first mobile management network element applied to a ground network, comprising: generating a second key for a first satellite according to a first key; wherein the first satellite is a candidate satellite for providing subsequent access service for a terminal device; the first key is a key for the terminal device received by the first mobile management network element from a home user service network element; sending the second key to a mobile management network element in the first satellite.

2. The method of claim 1, wherein, Before the step of generating the second key for the first satellite according to the first key, the method further comprises: receiving an identity of the terminal device from a mobile management network element on an initial satellite; when it is determined that the terminal device needs to be authenticated, sending an authentication data request to the home user service network element, the authentication data request comprising the identity of the terminal device; receiving an authentication data response from the home user service network element, the authentication data response comprising an initial authentication vector for authenticating the terminal device, the initial authentication vector comprising a random number RAND, an authentication token AUTN, an expected response XRES and the first key.

3. The method of claim 2, wherein, The method further comprises: determining that a second satellite is a candidate satellite for providing subsequent access service for the terminal device; sending the initial authentication vector to a mobile management network element in the second satellite.

4. The method of claim 3, wherein, The authentication data request further comprises indication information related to S&F operation; the authentication data response further comprises subscription data related to S&F operation; The initial authentication vector is carried in a message sent by the first mobile management network element to the mobile management network element in the second satellite, wherein the message further comprises the subscription data related to S&F operation and a key identifier; wherein the key identifier is used to identify the second key.

5. The method according to claim 3 or 4, characterized in that, Before the step of sending the second key to the mobile management network element in the first satellite, the method further comprises: receiving indication information from the mobile management network element in the second satellite, the indication information indicating that authentication for the terminal device is successful.

6. The method of claim 5, wherein, The initial satellite and the second satellite are different satellites or the same satellite, and the first satellite and the second satellite are different satellites.

7. The method of claim 2, wherein, The step of sending the second key to the mobile management network element in the first satellite specifically comprises: sending a deduced authentication vector to the mobile management network element in the first satellite; the deduced authentication vector comprising RAND, AUTN, XRES and the second key.

8. The method of claim 7, wherein, The initial satellite and the first satellite are different satellites or the same satellite.

9. The method according to any one of claims 1 to 8, characterized in that, The step of generating the second key for the first satellite according to the first key comprises: generating the second key using the first key and a first input parameter; wherein the first input parameter comprises one or more of the following: an identity of the first satellite, an identity of the mobile management network element in the first satellite or a key identifier; wherein the key identifier is used to identify the second key.

10. The method according to any one of claims 1 to 9, characterized in that, The first key is a root key K shared between the terminal device and the first mobile management network element ASME .

11. A communication method characterized by comprising: The method is applied to a terminal device, comprising: generating a second key for the first satellite according to the first key; wherein the first key is a key generated in a process that the terminal device attaches to a mobility management network element in the second satellite; and generating a non-access stratum (NAS) key according to the second key, the NAS key being used to protect messages between the terminal device and the mobility management network element in the first satellite; wherein the NAS key comprises a NAS ciphering key and a NAS integrity protection key.

12. The method of claim 11, wherein, The generating the NAS key according to the second key comprises: receiving a first NAS message from the mobility management network element in the first satellite, the first NAS message being used to indicate establishment of a secure connection; the first NAS message comprising a NAS integrity protection algorithm and a NAS ciphering algorithm; generating the NAS integrity protection key according to the second key and the NAS integrity protection algorithm, and generating the NAS ciphering key according to the second key and the NAS ciphering algorithm; The method further comprises: verifying integrity of the first NAS message according to the NAS integrity protection key and the NAS integrity protection algorithm; in case of successful integrity verification, sending a second NAS message to the mobility management network element of the first satellite, the second NAS message being used to respond to the indication of establishment of the secure connection.

13. The method of claim 12, wherein, The first NAS message further comprises a key identifier, wherein the key identifier is used to identify the second key; The generating the second key for the first satellite according to the first key comprises: generating the second key according to the first key and the key identifier.

14. The method of claim 12, wherein, The first NAS message further comprises an identity of the mobility management network element of the second satellite; The generating the second key for the first satellite according to the first key comprises: generating the second key for the first satellite according to the first key and the identity of the mobility management network element of the first satellite.

15. The method of claim 12, wherein, The method further comprises: receiving a broadcast message, the broadcast message comprising an identity of the first satellite; The generating the second key for the first satellite according to the first key comprises: generating the second key for the first satellite according to the first key and the identity of the first satellite.

16. The method of any one of claims 11-15, wherein, The method further comprises: storing a correspondence between the NAS key and the first satellite.

17. The method of claim 16, wherein, The method further comprises: when leaving the first satellite and communicating with the mobility management network element in the first satellite again, using the stored NAS key for messages between the terminal device and the mobility management network element in the first satellite.

18. The method according to any one of claims 11-17, characterized in that, The first satellite and the second satellite are the same satellite or different satellites.

19. The method according to any one of claims 11-18, characterized in that, The first key is a root key K shared between the terminal device and a first mobility management network element in the ground network ASME .

20. A communications device, characterized by comprises: a module for performing the method according to any one of claims 1 to 10, or a module for performing the method according to any one of claims 11 to 19.

21. A communication system, characterized by comprises: a communication device for performing the method according to any one of claims 1 to 10, and a communication device for performing the method according to any one of claims 11 to 19.

22. A computer-readable storage medium, characterized in that, A computer program product for storing computer program instructions, the computer program causing a computer to perform the method of any one of claims 1 to 19.

23. A computer program product, characterised in that, A computer program product comprising computer program instructions causing a computer to perform the method of any one of claims 1 to 19.

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