Method and communication apparatus

Abstract

The present application relates to a method and a communication apparatus. The method comprises: when a terminal device completes registration in a non-terrestrial network (NTN), the terminal device entering a first mode, wherein the terminal device does not need to initiate periodic registration to a first core network device of the NTN in the first mode. The terminal device completing the registration in the NTN can be understood as the terminal device sending to the first core network device a first message for requesting registration, and receiving, from the first core network device, a second message indicating that a registration request is accepted.

Description

Method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 28, 2023, with application number 202311088410.1 and application name “A Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular to a method and a communication device. Background Art

[0003] In non-terrestrial networks (NTN), terminal devices connect to access and core network equipment within the mobile communication network via satellite. Compared to terrestrial networks (TN), satellites are farther away from ground terminals, so communication between terminal devices and satellites increases their power consumption.

[0004] Summary of the Invention

[0005] Usually, a terminal device that is in the connection management (CM) idle state needs to initiate a periodic registration request to the core network device to maintain the terminal device in a registered state in the network. However, in the NTN communication scenario, if the terminal device periodically performs the registration update process, it will bring a large power consumption overhead to the terminal device. And if the terminal device is a terminal device that uses manual satellite alignment to perform the satellite alignment process, the terminal device cannot automatically perform the satellite alignment process periodically (or it is understood that the terminal device cannot guarantee the initiation of periodic registration updates), which causes the core network to believe that the terminal is unreachable and deregister the terminal device, affecting the timeliness of the terminal device's communication services. In order to solve the above technical problems, the embodiments of the present application provide a method and a communication device that are conducive to reducing the power consumption of terminal devices in NTN communication scenarios.

[0006] In a first aspect, the present application provides a method. Taking a terminal device executing the method as an example, the method includes: upon completion of terminal device registration in an NTN, the terminal device enters a first mode; wherein, in the first mode, the terminal device does not need to initiate periodic registration with a first core network device of the NTN; or, in the first mode, the terminal device initiates periodic registration with the first core network device for a first period, the first period being greater than a second period, the second period being the period for the terminal device to initiate periodic registration with a second core network device of a terrestrial network (TN).

[0007] In the method described in the first aspect, after the terminal device completes registration in the NTN, the terminal device enters a mode in which it does not need to initiate periodic registration with the first core device of the NTN (i.e., the first mode mentioned in this application), or the terminal device enters a mode in which the period for initiating periodic registration is longer, thereby reducing the satellite alignment process performed due to periodic registration, which is beneficial to saving power consumption of the terminal device.

[0008] In one possible implementation, the terminal device sends a first message to the first core network device, where the first message is used to request registration; further, the terminal device receives a second message from the first core network device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0009] In one possible implementation, the first message includes first information indicating that the terminal device cannot guarantee the execution of periodic registration, or the first information indicating that the terminal device requests not to perform periodic registration. By implementing this possible implementation, when the terminal device initiates a registration request to the NTN core network device (i.e., the first core network device), it requests not to perform periodic registration, which helps reduce its own power consumption.

[0010] In a possible implementation, the first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability to support NTN communication, and the second capability information indicates whether the terminal device has the capability of automatic satellite alignment.

[0011] In one possible implementation, the second message includes second information indicating that, after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN. By implementing this possible implementation, the first core network device can indicate whether the terminal device needs to initiate periodic registration in the first mode during the terminal device's registration process with the NTN, thereby increasing the flexibility of the terminal device initiating periodic registration in the first mode.

[0012] In one possible implementation, the second message also includes third information indicating a first duration, which is the duration of a periodic registration timer and is related to the duration of the terminal device's NTN service subscription. Furthermore, in the first mode, the terminal device does not need to initiate periodic registration with the first core network device of the NTN within the first duration. By implementing this possible implementation, the first core network device can indicate to the terminal device whether periodic registration is required in the first mode and the duration for which periodic registration is not required during the terminal device's registration process with the NTN, thereby increasing the flexibility of the terminal device in initiating periodic registration in the first mode.

[0013] In one possible implementation, the third information indicates that the periodic registration timer is inactivated. By implementing this possible implementation, the first core network device can, during the process of the terminal device registering with the NTN, indicate that the periodic registration timer is inactivated, thereby indicating that the terminal device does not need to initiate periodic registration in the first mode. This is conducive to improving the flexibility of the terminal device in determining whether to initiate periodic registration in the first mode.

[0014] In one possible implementation, the terminal device remains in a registered state and / or remains out of service in the first mode. By implementing this possible implementation, the terminal device remains in a registered state and / or remains out of service in the first mode, thereby avoiding the core network device from deregistering the terminal device, which is beneficial to improving the timeliness of terminal device communications (or being understood as facilitating rapid communication of the terminal device).

[0015] In a possible implementation, the terminal device does not need to monitor paging messages from the NTN in the first mode. By implementing this possible implementation, the terminal device does not monitor paging messages from the NTN in the first mode, which is conducive to reducing power consumption of the terminal device.

[0016] In one possible implementation, when a terminal device completes registration with a non-terrestrial network (NTN), the terminal device enters a first mode, including: when the terminal device completes registration and satisfies a first condition, the terminal device enters the first mode; wherein the first condition includes at least one of the following: the terminal device completes data transmission via the NTN; the terminal device transitions from a CM connected state to a CM idle state; the terminal device transitions from a first state to a second state, wherein the terminal device can communicate with the NTN satellite in the first state and cannot communicate with the NTN satellite in the second state; or the terminal device stops using NTN services. By implementing this possible implementation, after the terminal device completes registration with the NTN, the terminal device will only enter the first mode if the terminal device does not require NTN network services (i.e., the first condition is met). The terminal device will not enter the first mode if the terminal device requires NTN network services, thereby ensuring the reliability of terminal device services.

[0017] In one possible implementation, the terminal device transitions from the connection management (CM) connected state to the CM idle state, including: the terminal device transitions from the CM connected state to the CM idle state, and a duration for the terminal device to remain in the CM idle state is greater than a second duration, where the second duration is greater than 0. By implementing this possible implementation, after the terminal device completes registration with the NTN, the terminal device will enter the first mode only if the terminal device does not require NTN network services (i.e., satisfies a first condition). The terminal device will not enter the first mode if the terminal device requires NTN network services, thereby facilitating reliability of terminal device services.

[0018] In one possible implementation, after a terminal device enters the first mode, when the terminal device transitions from the second state to the first state, the terminal device sends a first message to the first core network device, requesting registration or service. In the first state, the terminal device can communicate with the NTN satellite, but in the second state, it cannot. By implementing this possible implementation, after entering the first mode, if the terminal device can communicate with the NTN satellite, the terminal device can still register with the NTN or request service, thereby ensuring the reliability of terminal device services.

[0019] In one possible implementation, after a terminal device enters the first mode, it exits the first mode if a second condition is met. The second condition includes at least one of the following: the terminal device transitions from the second state to the first state, where the terminal device can communicate with NTN's satellite in the first state and cannot communicate with NTN's satellite in the second state; the terminal device transitions from the CM Idle state to the CM Connected state; or the terminal device detects the execution of a satellite pointing operation. By implementing this possible implementation, after entering the first mode, if the terminal device requires NTN network services (e.g., if the second condition is met), the terminal device exits the first mode, thereby ensuring service reliability.

[0020] In a possible implementation, the first core network device only serves the NTN, or the first core network device serves the NTN and the TN.

[0021] In one possible implementation, the first core network device only serves the NTN. In this case, the terminal device sends a first message to the first core network device via the second core network device in the TN. Furthermore, the terminal device receives a second message from the first core network device via the second core network device. This possible implementation improves the flexibility of terminal device registration with the NTN.

[0022] In a possible implementation, the first message further includes a preference for the first mode; and the second message further includes information confirming acceptance of the preference.

[0023] In one possible implementation, the first message also includes a preference for the first mode, including: when the terminal device does not have automatic pointing capabilities, or when the terminal device selects manual pointing, the first message also includes a preference for the first mode. Implementing this possible implementation helps save power consumption for terminal devices using manual pointing.

[0024] In a possible implementation manner, the terminal device receives at least one equivalent public land mobile network EPLMN identifier from the second core network device, where the at least one EPLMN identifier includes a public land mobile network PLMN identifier of an NTN.

[0025] In one possible implementation, the terminal device receives at least one equivalent public land mobile network EPLMN identifier from a third core network device, where the at least one EPLMN identifier includes a public land mobile network PLMN identifier of the NTN. The third core network device is the core network device where the terminal device registers the PLMN.

[0026] In one possible implementation, a terminal device includes a first subscriber identity module (SIM) card and a second SIM card; the first SIM card is subscribed to a TN service, and the second SIM card is subscribed to an NTN service; further, the second SIM card sends a first message through the first SIM card; the first SIM card sends the first message to an access network device of the TN; the first SIM card receives a second message from the access network device of the TN; and the first SIM card sends the second message to the second SIM card.

[0027] In a second aspect, the present application provides a method, taking the first core network device of NTN as an example for executing the method, the method includes: when the terminal device completes registration in NTN, the first core network device of NTN determines that the terminal device enters a first mode; wherein, the terminal device does not need to initiate periodic registration to the first core network device of NTN in the first mode.

[0028] Based on the beneficial effects of the method described in the second aspect, reference can be made to the beneficial effects of the method described in the first aspect, which will not be repeated here.

[0029] In one possible implementation, the first core network device receives a first message from the terminal device, where the first message is used to request registration; further, the first core network device sends a second message to the terminal device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0030] In a possible implementation, the first message includes first information, where the first information indicates that the terminal device cannot guarantee to perform periodic registration, or the first information indicates that the terminal device requests not to perform periodic registration.

[0031] In one possible implementation, the first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability to support NTN communication, and the second capability information indicates whether the terminal device has the capability of automatic satellite alignment.

[0032] In one possible implementation, the first core network device determines a second message based on the first information; wherein the second message indicates at least one of the following: whether to accept the preferred information; whether the periodic registration timer is activated; when the periodic registration timer is activated, the duration of the periodic registration timer; or whether to perform implicit deregistration on the terminal device.

[0033] In a possible implementation, the second message includes second information, and the second information indicates that after the terminal device enters the first mode, there is no need to initiate periodic registration.

[0034] In one possible implementation, the second message also includes third information, which indicates a first duration, where the first duration is the duration of a periodic registration timer, and the first duration is related to the duration of the NTN service contracted by the terminal device; further, in the first mode, the terminal device does not need to initiate periodic registration to the first core network device of the NTN within the first duration.

[0035] In a possible implementation, the third information further indicates that the periodic registration timer is not activated.

[0036] In a possible implementation, the first core network device keeps the terminal device in the first mode in a registered state and / or out of service.

[0037] In a possible implementation, the first core network device does not need to send a paging message to the terminal device in the first mode.

[0038] In one possible implementation, when the terminal device completes registration in the non-terrestrial network NTN, the first core network device of the NTN determines that the terminal device enters the first mode, including: when the terminal device completes registration in the non-terrestrial network NTN and meets the third condition, the first core network device of the NTN determines that the terminal device enters the first mode; wherein the third condition includes one or more of the following: the terminal device converts from the connection management CM connection state to the CM idle state; the terminal device does not use the network service of the NTN within a third time period, and the third time period is greater than 0; or, the first core network device fails to page the terminal device.

[0039] In one possible implementation, the terminal device converts from the connection management CM connected state to the CM idle state, including: the terminal device converts from the CM connected state to the CM idle state, and the duration of the terminal device in the CM idle state is greater than a second duration, and the second duration is greater than 0.

[0040] In a possible implementation, after determining that the terminal device enters the first mode, the first core network device receives a first message from the terminal device, where the first message is used to request registration or request service.

[0041] In one possible implementation, when the fourth condition is met, the first core network device determines that the terminal device exits the first mode; wherein the fourth condition includes one or more of the following: the first core network device receives a first message from the terminal device, and the first message is used to request registration or request service; or, the terminal device switches from a CM idle state to a CM connected state.

[0042] In a possible implementation, the first core network device only serves the NTN, or the first core network device serves the NTN and the TN.

[0043] In a possible implementation, the first core network device receives a first message from the terminal device through the second core network device of the TN; the first core network device sends a second message to the terminal device through the second core network device.

[0044] In a possible implementation, the first message further includes a preference for the first mode; and the second message further includes information confirming acceptance of the preference.

[0045] In a third aspect, the present application provides a communication device. Exemplarily, the communication device may be a terminal device, a device in a terminal device, or a device that can be used in conjunction with a terminal device. Exemplarily, the communication device may also be a chip system. The communication device may execute the method described in the first aspect. The functions of the communication device may be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more units or modules corresponding to the above functions. The units or modules may be software and / or hardware. The operations performed by the communication device and the beneficial effects thereof may refer to the method and beneficial effects described in the first aspect above.

[0046] In a fourth aspect, the present application provides a communication device, which may be a core network device, a device in a core network device, or a device that can be used in conjunction with a core network device. The communication device may also be a chip system. The communication device may execute the method described in the second aspect. The functions of the communication device may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions. The units or modules may be software and / or hardware. The operations and beneficial effects performed by the communication device may refer to the method and beneficial effects described in the second aspect above.

[0047] In a fifth aspect, the present application provides a communication device, which includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor implements the method as described in the first aspect or the method as described in the second aspect through logic circuits or execution code instructions.

[0048] In a sixth aspect, the present application provides a computer-readable storage medium, in which a computer program or instruction is stored. When the computer program or instruction is executed by a communication device, the method described in the first aspect or the method described in the second aspect is implemented.

[0049] In a seventh aspect, the present application provides a computer program product comprising instructions, which, when read and executed by a communication device, enables the method described in the first aspect or the method described in the second aspect to be implemented.

[0050] In an eighth aspect, the present application provides a communication system, which includes a communication device for executing the method described in the first aspect, and a communication device for executing the method executed by the core network device described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a schematic diagram of a network system architecture provided in an embodiment of the present application;

[0052] FIG2 is a schematic diagram of a CN structure provided in an embodiment of the present application;

[0053] FIG3 a is a schematic diagram of a transparent satellite architecture provided in an embodiment of the present application;

[0054] FIG3 b is a schematic diagram of a regenerative satellite architecture provided in an embodiment of the present application;

[0055] FIG3c is a schematic diagram of a process of implicit deregistration provided in an embodiment of the present application;

[0056] FIG4 is a flow chart of a method provided in an embodiment of the present application;

[0057] FIG5 is a schematic diagram of a process for registering a terminal device in an NTN according to an embodiment of the present application;

[0058] FIG6 is a schematic diagram of third information provided in an embodiment of the present application;

[0059] 7 is a schematic diagram of another terminal device registration process in the NTN provided in an embodiment of the present application;

[0060] FIG8 is a schematic diagram of another terminal device registration process in the NTN provided in an embodiment of the present application;

[0061] FIG9a is a schematic diagram of another terminal device registration process in the NTN provided in an embodiment of the present application;

[0062] FIG9 b is a schematic diagram of another terminal device registration process in the NTN provided in an embodiment of the present application;

[0063] FIG10 is a schematic diagram of another terminal device registration process in the NTN according to an embodiment of the present application;

[0064] FIG11 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0065] FIG12 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] The terms "first" and "second" and the like in the specification, claims, and drawings of this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0067] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It should be understood that the embodiments described herein may be combined with other embodiments.

[0068] In order to facilitate a detailed understanding of the embodiments of the present application, the system architecture involved in the embodiments of the present application is first introduced below.

[0069] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), new radio (NR), the 3rd generation partner project (3GPP) service-based network architecture (SBA), and other fifth generation (5G) communication systems or sixth generation (6G) communication systems and other communication systems evolved after 5G.

[0070] Please refer to Figure 1, which is a schematic diagram of a network system architecture provided by an embodiment of the present application. As shown in Figure 1, a terminal device can access a wireless network to obtain services of an external network (such as a data network (DN)) through the wireless network, or communicate with other devices through the wireless network, such as communicating with other terminal devices. The wireless network includes a (radio) access network ((R)AN) and a core network (CN), wherein the (R)AN (hereinafter described as RAN) is used to access the terminal device to the wireless network, and the CN is used to manage the terminal device and provide a gateway for communicating with the DN. The terminal device, RAN, CN and DN involved in the system architecture in Figure 1 are described in detail below.

[0071] 1. Terminal Equipment

[0072] Terminal devices include devices that provide voice and / or data connectivity to users. For example, a terminal device is a device with wireless transceiver capabilities that can be deployed on land, including indoors or outdoors, handheld, wearable, or vehicle-mounted; it can also be deployed on the water (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons, and satellites, etc.). The terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a vehicle-mounted terminal, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a wearable terminal, etc. The embodiments of the present application do not limit the application scenarios. Terminal equipment may sometimes also be referred to as terminal, user equipment (UE), access terminal, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, mobile station, remote station, remote terminal, mobile device, UE terminal, wireless communication equipment, UE agent or UE device, etc. The terminal may also be fixed or mobile. It will be understood that all or part of the functions of the terminal in this application may also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (such as a cloud platform). The terminal device in this application may be a terminal for 5G or a terminal for 6G, and this application does not limit this.

[0073] 2. RAN

[0074] The RAN may include one or more RAN devices (or access network devices). The interface between the access network device and the terminal device may be a Uu interface (or air interface). Of course, in communications evolved after 5G, the names of these interfaces may remain unchanged or may be replaced by other names, and this application does not limit this.

[0075] Access network equipment is a node or device that connects a terminal device to a wireless network. Examples of access network equipment include, but are not limited to, next generation node B (gNB), evolved node B (eNB), next generation eNB (ng-eNB), wireless backhaul equipment, radio network controller (RNC), node B (NB), home evolved node B (HeNB) or home node B (HNB), baseband unit (BBU), transmitting and receiving point (TRP), transmitting point (TP), mobile switching center, and equipment that performs base station functions in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications in 5G communication systems. It may also include centralized units (C-RAN) in cloud radio access network (C-RAN) systems. The RAN in this application may be a 5G RAN or a 6G RAN, and this application does not limit this.

[0076] 3. CN

[0077] The CN may include one or more CN devices (which may be understood as network element devices or network functions (NFs)). In the following text, the CN devices are collectively referred to as core network devices (eg, the first core network device and the second core network device in the following text).

[0078] Please refer to Figure 2, which is a structural diagram of a CN provided by this application. The CN in Figure 2 is a schematic diagram of the CN in the 5G network architecture. The CN shown in Figure 2 includes multiple CN devices: network slice selection function (NSSF), network exposure function (NEF), network function repository function (NRF), policy control function (PCF), unified data management (UDM), application function (AF), network control function (NCF), network slice specific authentication and authorization function (NSSAAF), authentication server function (AUSF), access and mobility management function (AMF), session management function (SMF), user plane function (UPF), service communication proxy (SCP), network slice admission control function (NSACF). Among them:

[0079] The AMF is a control plane function provided by the operator network, responsible for access control and mobility management of terminal devices accessing the operator network, such as mobility status management, allocating temporary user identities, and authenticating and authorizing users.

[0080] SMF is a control plane function provided by the operator network, responsible for managing the protocol data unit (PDU) sessions of terminal devices. A PDU session is a channel for transmitting PDUs. Terminal devices need to transmit PDUs to and from the DN through PDU sessions. The SMF is responsible for establishing, maintaining, and deleting PDU sessions. SMF includes session management (such as session establishment, modification, and release, including tunnel maintenance between the UPF and RAN), UPF selection and control, service and session continuity (SSC) mode selection, roaming, and other session-related functions.

[0081] The PCF is a control plane function provided by the operator, including user subscription data management, policy control, charging policy control, and Quality of Service (QoS) control. It is mainly used to provide PDU session policies to the SMF. Among them, the policies may include charging-related policies, QoS-related policies, and authorization-related policies.

[0082] The UPF is a gateway provided by the operator, serving as the gateway for communication between the operator's network and the DN. The UPF includes user-plane-related functions such as packet routing and transmission, packet inspection, quality of service (QoS) processing, uplink packet inspection, and downlink packet storage.

[0083] The UDM is primarily used to manage user subscription and authentication data, as well as perform authentication credit processing, user identity processing, access authorization, registration / mobility management, subscription management, and short message management. In some embodiments, the UDM may also include a unified data repository (UDR). Alternatively, in other embodiments, the 3GPP SBA of the 5G system may also include a UDR. The UDR is used to provide storage and retrieval for PCF policies, storage and retrieval of open structured data, and storage of user information requested by application functions.

[0084] NRF is mainly used to register, manage, and detect the status of other NFs to achieve automated management of all NFs. When each NF is started, it must register with NRF before it can provide services. The registration information includes NF type, address, service list, etc.

[0085] NEF is mainly used to support secure interaction between the network and third-party applications. The network can securely expose network capabilities and events to third parties through NEF to enhance or improve the quality of application services. In addition, the network can securely obtain relevant data from third parties through NEF to enhance the network's intelligent decision-making. At the same time, NEF supports recovering structured data from UDR or storing structured data in UDR.

[0086] AF is mainly used to support interaction with the core network to provide services, such as influencing data routing decisions, policy control functions, or providing some third-party services to the network side.

[0087] The above-mentioned CN devices may also be referred to as network elements or functional network elements. In a 5G communication system, each functional network element may be the name of each functional network element shown in FIG2 . In a communication system evolved after 5G (such as a 6G communication system), each functional network element may still be the name of each functional network element shown in FIG2 , or may have other names. For example, in a 5G communication system, a policy control network element may be a PCF. In a communication system evolved after 5G (such as a 6G communication system), the policy control function may still be a PCF, or may have other names, which is not limited in this application.

[0088] In Figure 2, Npcf, Nudm, Naf, Namf, Nsmf, N1, N2, N3, N4, and N6 are interface serial numbers. The meanings of these interface serial numbers can be found in the definitions of relevant standard protocols and are not limited here.

[0089] 4. DN

[0090] DN, also known as packet data network (PDN), is a network located outside the operator network. The operator network can access multiple DNs. Application servers corresponding to various services can be deployed in the DN to provide a variety of possible services for terminal devices.

[0091] It should be noted that the system architecture shown in FIG1 is merely illustrative and cannot be regarded as a specific limitation on the technical solution of the present application.

[0092] In order to facilitate understanding of the relevant contents of the embodiments of the present application, some of the terms involved in the embodiments of the present application are explained below. This part is only for ease of understanding and cannot be regarded as a disclosure or specific limitation of the technical solution of the present application.

[0093] 1. NTN

[0094] NTN is a communication system that provides communication services (such as wireless access or backhaul) to terminal devices through non-terrestrial network equipment (such as ships, high-altitude platforms, drones or satellites), thereby achieving seamless communication coverage to improve the reliability of the communication system. For example, 5G NTN or NRNTN and future 6G NTN systems can help meet the demand for wireless connection anytime and anywhere by providing wider regional coverage and ensuring service availability, continuity and scalability. It should be noted that, for ease of understanding, the following text only uses the example of a satellite as the non-terrestrial network device in NTN, which should not be regarded as a specific limitation of this application.

[0095] When non-terrestrial network devices are satellites, these involve low Earth orbit (LEO), medium Earth orbit (MEO), and geostationary Earth orbit (GEO) satellites. The role of the satellite can also vary depending on the different access methods provided by the NTN. For example, in a transparent satellite architecture shown in Figure 3a, the satellite provides access technology connecting terminal devices to the terrestrial network. The satellite's role is to perform radio frequency filtering, frequency conversion, and amplification. In this transparent satellite architecture, the satellite primarily serves as a Layer 1 (L1) relay device between the terminal and the ground base station, regenerating the physical layer signal (i.e., radio frequency filtering, frequency conversion, and amplification processing), without any other higher protocol layers. In a regenerative satellite architecture shown in Figure 3b, some or all of the base station's functions are integrated into the satellite. It should be noted that in a regenerative satellite architecture, some or all of the base station's functions, as well as some or all of the core network's functions, can also be integrated into the satellite, thereby providing shorter transmission latency.

[0096] Typically, satellites in an NTN communicate with the ground network (including access network equipment and / or core network equipment) through a gateway station (such as the gateway station shown in Figure 3a or Figure 3b). The gateway station (also referred to as a ground station) mentioned in this application can be understood as the gateway in the NTN.

[0097] 2. The process of satellite alignment of terminal equipment

[0098] In NTN communication scenarios, due to the long distance between ground terminals and satellites and limited link budget, when communicating with satellites, terminal devices need to perform a satellite alignment process to improve signal gain and ensure effective communication with the satellite.

[0099] The satellite pointing process of the terminal device can be understood as the process in which the terminal device adjusts the antenna attitude so that the radiation direction of the antenna is aligned with the target satellite, so that the terminal device can communicate with the satellite; adjusting the antenna attitude can be understood as the process in which the terminal device adjusts the azimuth, elevation and polarization angles of the antenna so that the center of the antenna beam of the terminal device is aligned with the satellite.

[0100] In NTN communication scenarios, terminal devices must first perform a satellite alignment process so that they can communicate with NTN's satellites (or the terminal device is in the alignment state). Only then can the terminal device connect to access network equipment and core network equipment to obtain NTN services (or network services). If the terminal device does not perform the satellite alignment process, that is, the terminal device cannot communicate with NTN's satellites (or the terminal device is in the non-aligned state), the terminal device cannot obtain NTN services.

[0101] 3. Periodic registration

[0102] A terminal device must successfully register with the core network equipment of a communication network before it can receive communication services provided by that communication network. The communication network includes, but is not limited to, an NTN or a terrestrial network (TN). After a registered terminal device enters an idle state, the core network equipment of the communication network can determine whether the terminal device is reachable by checking whether the terminal device has performed periodic registrations. This ensures that the terminal device can subsequently communicate normally with the network.

[0103] Specifically, the terminal device is configured with a periodic registration timer, and the terminal device initiates periodic registration according to the periodic registration timer. It can be understood that when the terminal device enters the idle state, the periodic registration timer is started; when the periodic registration timer times out, the terminal device sends a periodic registration request to the core network device, so that the core network device knows that the terminal device is still reachable; after the terminal device sends the periodic registration request, it resets the periodic registration timer after entering the idle state again, and waits for the next time the periodic registration timer times out again, and then sends the periodic registration request again. If the terminal device does not send a periodic registration request to the core network device after the periodic registration timer times out, or it is understood that the core network device has not received the periodic registration request, it is deemed that the terminal device has not performed periodic registration on time.

[0104] 4. Register

[0105] Deregistration is the process by which the network (e.g., core network equipment) releases the relevant information of the terminal device (e.g., session information, context information, etc.). After the terminal device is deregistered, it needs to obtain services from the communication network again and must register again (i.e., perform the initial registration process).

[0106] It should be noted that the implicit deregistration mentioned in this application can be understood as the situation where the core network device performs deregistration on the terminal device without notifying the terminal device. For a detailed explanation of implicit deregistration, please refer to 3GPP TS23.501.

[0107] Please refer to Figure 3c, which is a schematic diagram of an implicit deregistration process provided by an embodiment of the present application. In Figure 3c, the core network device is configured with a mobile reachable timer and an implicit deregistration timer, wherein the value of the mobile reachable timer is greater than the value of the periodic registration timer. When the terminal device enters the idle state, the core network device starts the mobile reachable timer; if the mobile reachable timer times out and the core network device still does not receive the registration request message sent by the terminal device, the network side considers that the terminal device is unreachable and starts the implicit deregistration timer; if the implicit deregistration timer times out and the terminal device still does not send a registration request message to the core network device, the core network device implicitly deregisters the terminal device and deletes the relevant information of the terminal device.

[0108] After the terminal device enters the CM idle state, it needs to periodically perform the registration update process according to the requirements of the core network (such as the periodic registration update timer) to ensure that the core network considers the terminal device reachable so that the terminal device can subsequently communicate normally with the network. In the NTN communication scenario, if the terminal device periodically performs the registration update process, it is necessary to periodically perform the satellite alignment process, which brings a large power consumption overhead to the terminal device. In addition, when the terminal device uses manual satellite alignment to perform the satellite alignment process, the terminal device cannot automatically perform the satellite alignment process periodically (or it is understood that the terminal device cannot guarantee to initiate periodic registration updates), which causes the core network to consider the terminal unreachable and deregister the terminal device, affecting the timeliness of the terminal device's communication services.

[0109] In order to reduce the power consumption overhead of the terminal device and improve the timeliness of the communication services of the terminal device, the present application provides a method and a communication device. The method and communication device provided by the embodiment of the present application are described in detail below in conjunction with the accompanying drawings. Figure 4 is a flow chart of a method provided by an embodiment of the present application. As shown in Figure 4, the method includes the following steps S401, and the method execution subject shown in Figure 4 is illustrated by taking the terminal device and the first core network device of NTN as an example. It can be understood that the method execution subject shown in Figure 4 can also be a module (for example, a chip) in the terminal device and a module (for example, a chip) in the first core network device. Wherein:

[0110] S401: When the terminal device completes registration in the NTN, the terminal device enters the first mode. Accordingly, when the terminal device completes registration in the NTN, the first core network device of the NTN determines that the terminal device enters the first mode.

[0111] For the terminal device, after the terminal device enters the first mode, the terminal device does not need to initiate periodic registration with the first core network device of NTN in the first mode; or, it is understood that the period for the terminal device to initiate periodic registration with the first core network device in the first mode (hereinafter referred to as the first period for the sake of ease of description) is greater than the period for the terminal device to initiate periodic registration with the second core network device of TN (hereinafter referred to as the second period for the sake of ease of description). In a possible implementation, the terminal device also has one or more of the following features in the first mode: ① Maintaining a registered state and / or maintaining no service, ② No need to monitor paging messages from NTN. Among them, maintaining no service can be understood as the terminal device entering a no service state.

[0112] For the first core network device of NTN, the terminal device configured in the first mode by the first core network device does not need to send a periodic registration to the first core network device of NTN; or, the first period configured by the first core network device is greater than the second period. In one possible implementation, after the first core network device determines that the terminal device has entered the first mode, it may also perform one or more of the following operations: ① Maintain the registration status of the terminal device in the first mode and / or maintain no service. It can be understood that the first core network device will not trigger the process of implicit deregistration of the terminal device, or the first core network device sets the implicit deregistration timer to infinity (or understood as a larger value, or understood as deactivating the implicit registration timer). ② There is no need to send a paging message to the terminal device, or it is understood that there is no need to page the terminal device.

[0113] In one possible implementation, after the terminal device enters the first mode, when the terminal device transitions from the second state to the first state, the terminal device sends a first message to the first core network device. The terminal device can communicate with the NTN satellite in the second state, but cannot communicate with the NTN satellite in the first state. For example, the second state is a state where the terminal device is not aligned with the satellite (or called an unaligned state), while the first state is a state where the terminal device is aligned with the satellite (or called an aligned state). The first message is used to request registration or service, for example, a registration request message or a service request message. That is, after the terminal device enters the first mode, if the terminal device requires NTN services, the terminal device can transition from the second state to the first state. After the terminal device transitions to the first state, the terminal device sends the first message to the first core network device via the NTN satellite to request registration or service.

[0114] It should be noted that the timing at which the terminal device enters the first mode and the timing at which the first core network device determines that the terminal device enters the first mode may be the same as or different from each other, and this application does not specifically limit this. Correspondingly, the timing at which the terminal device exits the first mode and the timing at which the first core network device determines that the terminal device exits the first mode may be the same as or different from each other, and this application does not specifically limit this.

[0115] The following describes the timing when the terminal device enters the first mode, the timing when the terminal device exits the first mode, the timing when the first core network device determines that the terminal device enters the first mode, and the timing when the first core network device determines that the terminal device exits the first mode.

[0116] 1. The timing when the terminal device enters the first mode.

[0117] In one case, after the terminal device completes registration in the NTN, the terminal device can enter the first mode. That is, in this case, the terminal device can enter the first mode if it meets the condition of completing registration in the NTN.

[0118] In another case, in addition to meeting the conditions for completing registration in the NTN, the terminal device will enter the first mode only if a first condition is met. The first condition includes at least one of the following conditions:

[0119] Condition 1: The terminal device completes data transmission via the NTN. It should be understood that Condition 1 includes either of the following two interpretations: ① When the terminal device completes data transmission via the NTN; ② When the terminal device completes data transmission via the NTN and does not transmit data via the NTN within a fourth time period, where the fourth time period is greater than 0.

[0120] Condition 2: The connection management state of the terminal device transitions from the CM-Connected state to the CM-Idle state. It should be understood that Condition 2 includes either of the following two interpretations: ① When the terminal device transitions from the CM-Connected state to the CM-Idle state; or ② When the terminal device transitions from the CM-Connected state to the CM-Idle state, and the duration of the terminal device's stay in the CM-Idle state is greater than a second duration, where the second duration is greater than 0.

[0121] Condition 3: The terminal device transitions from a first state to a second state, wherein in the first state the terminal device can communicate with NTN's satellite, and in the second state the terminal device cannot communicate with NTN's satellite. It should be understood that Condition 3 includes either of the following two interpretations: ① When the terminal device transitions from the first state to the second state; or ② When the terminal device transitions from the first state to the second state, and the duration of the terminal device's stay in the second state is greater than a fifth duration, where the fifth duration is greater than 0.

[0122] Condition 4: The terminal device ceases to use NTN services. It should be understood that Condition 4 includes either of the following two interpretations: ① When the terminal device transitions from using NTN services to ceasing to use NTN services; or ② When the terminal device transitions from using NTN services to ceasing to use NTN services, and the terminal device continues to not use NTN services within a sixth period, where the sixth period is greater than zero.

[0123] 2. The timing for the terminal device to exit the first mode.

[0124] After the terminal device enters the first mode, the terminal device exits the first mode if a second condition is met; wherein the second condition includes at least one of the following conditions:

[0125] Condition 5: The terminal device switches from the second state to the first state, wherein in the first state the terminal device can communicate with the NTN satellite, and in the second state the terminal device cannot communicate with the NTN satellite.

[0126] Condition 6: When the terminal device needs to switch from the CM idle state to the CM connected state, for example, when the terminal device has uplink signaling or data transmission requirements.

[0127] Condition 7: The terminal device detects that a satellite alignment operation is being performed; that is, the terminal device is performing operations related to the satellite alignment process.

[0128] 3. The first core network device determines the timing for the terminal device to enter the first mode.

[0129] In one case, when the terminal device completes registration in the NTN, the first core network device determines that the terminal device has entered the first mode. In other words, in this case, if the condition of completing registration in the NTN is met, the first core network device determines that the terminal device has entered the first mode.

[0130] In another case, in addition to the condition of registration completion in the NTN, the first core network device determines that the terminal device has entered the first mode only when a third condition is met. The third condition includes at least one of the following conditions:

[0131] Condition 8: The connection management state of the terminal device transitions from the CM-connected state to the CM-idle state. It should be understood that Condition 8 includes either of the following two interpretations: ① The first core network device detects that the connection management state of the terminal device transitions from the CM-connected state to the CM-idle state; ② The first core network device detects that the terminal device transitions from the CM-connected state to the CM-idle state, and the duration of the terminal device being in the CM-idle state is greater than a second duration, where the second duration is greater than 0.

[0132] Condition 9: The first core network device detects that the terminal device has not used the NTN network service within a third time period, and the third time period is greater than 0.

[0133] Condition 10: When the first core network device fails to page the terminal device. This condition 10 can be understood as when the terminal device is in the CM idle state, the first core network device fails to send a paging message to the terminal device, for example, the first core network device does not receive a response from the terminal device after sending a paging message to the terminal device.

[0134] 4. The first core network device determines the timing for the terminal device to exit the first mode.

[0135] After the first core network device determines that the terminal device enters the first mode, the first core network device determines that the terminal device exits the first mode if a fourth condition is met. The fourth condition includes one or more of the following conditions:

[0136] Condition 11: The first core network device receives a first message from the terminal device, where the first message is used to request registration or service.

[0137] Condition 12: The first core network device detects that the connection management state of the terminal device is changed from CM idle state to CM connected state.

[0138] To sum up, in the method described in Figure 4, after the terminal device completes registration in the NTN, the terminal device can enter a mode in which it does not need to initiate periodic registration to the first core device of the NTN (that is, the first mode mentioned in this application), or the terminal device enters a mode in which the period for initiating periodic registration is longer, thereby reducing the satellite alignment process performed due to periodic registration, which is beneficial to saving power consumption of the terminal device.

[0139] In the method described in Figure 4 , the terminal device completes registration with the NTN, which can be understood as the terminal device performing a registration process with the NTN. This process primarily includes the following two steps: S1. The terminal device sends a first message to a first core network device of the NTN, requesting registration; S2. The terminal device receives a second message from the first core network device, instructing the first core network device to accept the terminal device's registration request. In the method described in Figure 4 , the first core network device can serve only the NTN (which can be understood as the NTN core network device when the NTN core network device is different from the TN core network device), or it can serve both the NTN and the TN (which can be understood as the NTN core network device when the NTN and the TN share all or some of the same core network devices). The following describes the terminal device registration process with the NTN in detail, divided into the following scenarios, using the method described in Figure 4 .

[0140] Case 1: The operator corresponding to NTN can be an exclusive operator of NTN, mainly operating NTN. In this case, it can be understood that the first core network device only serves NTN. The registration process of the terminal device in NTN can be shown in Figure 5. Among them:

[0141] S501. The terminal device sends a first message to the first core network device, where the first message is used to request registration.

[0142] After the terminal device performs the satellite alignment process, the terminal device sends a first message (e.g., a registration request message) to the NTN access network device for requesting registration. The NTN access network device then forwards the first message to the first core network device. It should be noted that the NTN access network device may or may not be deployed on a satellite, and this application does not specifically limit this. For ease of understanding, in this application, after the terminal device performs the satellite alignment process, it can be understood that the terminal device can communicate with the NTN access network device.

[0143] In one possible implementation, the first message includes at least one of the following: a preference for the first mode, first information, first capability information, or second capability information. The first information indicates that the terminal device cannot guarantee periodic registration, or that the terminal device requests not to perform periodic registration; the first capability information indicates whether the terminal device has the capability to support NTN communications; and the second capability information indicates whether the terminal device has the capability for automatic satellite pointing. It is understood that, in addition to the first information, the first message may also include other information (e.g., a preference for the first mode, registration request information, etc.).

[0144] When the first message includes a preference for the first mode, it indicates that the terminal device expects to subsequently enter the first mode if conditions are met. That is, if the terminal device expects to subsequently enter the first mode if conditions are met, the first message may include a preference for the first mode. In one possible implementation, the first message includes a preference for the first mode only when the terminal device does not have automatic tracking capabilities (or is understood to have only automatic tracking capabilities) or when the user selects manual tracking for the terminal device. Otherwise, the first message may not include a preference for the first mode. For example, when the terminal device detects an NTN, it outputs a prompt message through the user interface (UI) indicating whether to enter the first mode and whether calls cannot be received in the first mode. After the user enters confirmation information according to the prompt message, it can be understood that the user selects manual tracking for the terminal device. In this case, the first message sent by the terminal device to the first core network includes a preference for the first mode.

[0145] In Example 1, the first message includes a preference for the first mode. In this case, after receiving the first message, the first core network device can determine whether to accept the terminal device's preference for the first mode based on the terminal device's NTN subscription information. For example, if the terminal device's NTN subscription information includes subscription information that allows entry into the first mode, the first core network device determines to accept the terminal device's preference for the first mode.

[0146] When the first message includes at least one of the first information, the first capability information, or the second capability information, the first core network device can determine at least one of the following based on the first information: ① whether the terminal device can enter the first mode after completing registration with the NTN (which can also be understood as determining whether the terminal device's preference for the first mode is accepted); ② whether the periodic registration timer is activated; ③ if the periodic registration timer is activated, the duration of the periodic registration timer; ④ whether to perform implicit deregistration on the terminal device; or, ⑤ if the periodic registration timer is not activated, not activating the reachable timer and the implicit deregistration timer, thereby not performing the implicit deregistration process. In one possible implementation, when the second capability information indicates that the terminal device does not have the capability of automatic satellite alignment, it can be understood that the second capability information also indicates that the terminal device cannot guarantee the execution of periodic registration. When the first capability information indicates that the terminal device has the capability of NTN communication and the second capability information indicates that the terminal device does not have the capability of automatic satellite alignment, the first capability information and the second capability information indicate that the terminal device cannot guarantee the execution of periodic registration. It can be understood that, in this possible implementation, the content indicated by the first information is indicated by the first capability information and / or the second capability information, that is, it can be understood that the first information includes the first capability information and / or the second capability information.

[0147] In Example 2, the first message includes first capability information, which indicates that the terminal device has the ability to support NTN communication. In this case, the first core network device can determine that after the terminal device completes registration in the NTN based on the first capability information, the terminal device can enter the first mode. In one possibility of Example 2, the first core network device can also determine to activate the periodic registration timer corresponding to the terminal device based on the terminal device's subscription information about NTN (for example, the duration of the terminal device's subscription to the NTN service), and determine the duration of the periodic registration timer to be the first duration; it can also determine to activate a reachable timer and an implicit deregistration timer, and the duration of the reachable timer is greater than the first duration, and the duration of the implicit deregistration timer is greater than the first duration; and the terminal device is not implicitly deregistered before the implicit deregistration timer times out.

[0148] In Example 3, the first message includes second capability information, which indicates that the terminal device does not have the ability to automatically align with the satellite, or indicates that the terminal device can only perform the alignment process through manual operation (that is, it indicates that the terminal device only has the ability to manually align with the satellite). In this case, the first core network device can determine, based on the second capability information, that after the terminal device completes registration in the NTN, the terminal device can enter the first mode. In one possibility of Example 3, the first core network device can also determine to activate the periodic registration timer corresponding to the terminal device based on the contract information of the terminal device about the NTN (for example, the duration of the terminal device's contract for the NTN service), and determine the duration of the periodic registration timer to be the first duration; it can also determine to activate the reachable timer and the implicit deregistration timer, and the duration of the reachable timer is greater than the first duration, and the duration of the implicit deregistration timer is greater than the first duration; and the terminal device is not implicitly deregistered before the implicit deregistration timer times out.

[0149] It should be noted that the first capability information described in this application indicates whether a terminal device has the ability to support NTN communications, including both explicit and implicit indications. The second capability information also indicates whether a terminal device has the ability to automatically point to a satellite, including both explicit and implicit indications. For ease of understanding, the following description uses the explicit and implicit indications corresponding to the first capability information as examples.

[0150] For example, the first capability information corresponds to field 1. In an explicit indication mode, when the value of field 1 is 0, the first capability information indicates that the terminal device has the capability to support NTN communications; when the value of field 1 is 1, the first capability information indicates that the terminal device does not have the capability to support NTN communications. In an implicit indication mode, when field 1 is included in the first message, the first capability information indicates that the terminal device has the capability to support NTN communications; when field 1 is not included in the first message, the first capability information indicates that the terminal device does not have the capability to support NTN communications. Alternatively, in another implicit indication mode, when field 1 is included in the first message, the first capability information indicates that the terminal device does not have the capability to support NTN communications; when field 1 is not included in the first message, the first capability information indicates that the terminal device has the capability to support NTN communications.

[0151] S502. The terminal device receives a second message from the first core network device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0152] After the first core network device receives the first message through the NTN access network device, the first core network device determines to accept the terminal device's registration request based on the terminal device's NTN subscription information. Furthermore, the first core network device sends a second message (e.g., a registration acceptance message) to the NTN access network device, which then forwards the second message to the terminal device.

[0153] In one possible implementation, the second message includes at least one of the following information: information confirming acceptance of the terminal device's preference for the first mode, second information, or third information. The second information indicates that after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN; the third information indicates a first duration (i.e., the duration of the periodic registration timer, which is related to the duration of the terminal device's contracted NTN service), and / or the third information indicates whether the periodic registration timer is activated. In one possible implementation of the third information, the third information consists of two parts: a first part indicating the length of the periodic registration timer, and a second part indicating a multiple (i.e., the unit corresponding to the length of the periodic registration timer, such as 10s, 10min, 1h, etc.); when the second part is the first value, the third information indicates that the periodic registration timer is not activated; when the second part is another value (i.e., not the first value), the third information indicates that the periodic registration timer is activated, and the value of the second part (i.e., the other value) indicates the multiple. For example, the third information is shown in Figure 6. When the second part indicates 111 (i.e., the first value), the third information indicates that the periodic registration timer is not activated; when the second part indicates 100, the second part indicates that the periodic registration timer is activated, and the multiple is 1h. If the first part indicates that the length of the periodic registration timer is 60, the third information indicates that the first duration is 60h.

[0154] It is understood that when the second message includes information confirming acceptance of the terminal device's preference for the first mode, or includes the second information, the terminal device can subsequently enter the first mode if the conditions for entering the first mode (such as the aforementioned first condition) are met. When the second message includes the third information, after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device within the first duration indicated by the third information.

[0155] For example, continuing with Example 1 in S501 , the second message includes information for determining the preference of the receiving terminal device for the first mode.

[0156] For example, following Example 2 in S501, the second message includes the second information. In a possible implementation, the second message also includes third information indicating the activation period registration timer and the first duration.

[0157] For example, following Example 3 in S501, the second message includes the second information. In a possible implementation, the second message also includes third information indicating the activation period registration timer and the first duration.

[0158] Case 2: The operator corresponding to the NTN is different from the operator corresponding to the TN. The operator corresponding to the NTN has a cooperative relationship with the operator corresponding to the TN. This means that the first core network device and the second core network device have a communication connection and can communicate with each other. In this case, it can be understood that the first core network device only serves the NTN. The registration process of the terminal device in the NTN can be seen in Figure 7. Among them:

[0159] S701. The terminal device sends a first message to the first core network device through the second core network device, where the first message is used to request registration.

[0160] That is, the terminal device sends the first message to the second core network device through the TN access network device, and further, the second core network device forwards the first message to the first core network device. For the specific description of the first message, please refer to the specific description of the first message in S501, which will not be repeated here.

[0161] In one possible implementation, the terminal device includes a first subscriber identity module (SIM) card and a second SIM card. The first SIM card is subscribed to TN services, and the second SIM card is subscribed to NTN services. In this case, the implementation process of S701 is shown in Figure 8, including: the terminal device sends a first message to the first SIM card via the second SIM card; the first SIM card sends the first message to a TN access network device; the TN access network device sends the first message to a second core network device; and the second core network device forwards the first message to the first core network device.

[0162] In a possible implementation, at least one of the first SIM card or the second SIM card is an embedded SIM (eSIM) card.

[0163] S702. The terminal device receives a second message from the first core network device through the second core network device. The second message indicates that the registration request of the terminal device is accepted.

[0164] That is, after the first core network device receives the first message, it determines to accept the terminal device's registration request based on the terminal device's NTN subscription information. Furthermore, the first core network device sends a second message to the second core network device, which in turn sends the second message to the TN access network device. The TN access network device then sends the second message to the terminal device. For a detailed description of the second message, refer to the detailed description of the second message in S502 and will not be repeated here.

[0165] In one possible implementation, the terminal device includes a first SIM card and a second SIM card. The first SIM card is subscribed to TN services, and the second SIM card is subscribed to NTN services. In this case, the implementation process of S702 is shown in Figure 8 , including: the first core network device sends a second message to the second core network device; the second core network device sends the second message to the TN access network device; the TN access network device sends the second message to the first SIM card, and the first SIM card sends the second message to the second SIM card. After the second SIM card receives the second message, it is considered that the terminal device in S702 has received the second message.

[0166] Case 3: The public land mobile network (PLMN) corresponding to the NTN is different from the PLMN corresponding to the TN. For example, the same operator operates both the TN and NTN, and the TN and NTN correspond to different PLMNs. Alternatively, the operator to which the NTN belongs is different from the operator to which the TN belongs, but the operator to which the NTN belongs has a roaming agreement with the operator to which the TN belongs. For example, users of the operator to which the TN belongs can roam to the NTN with a roaming agreement, and users of the operator to which the NTN belongs can also roam to the TN with a roaming agreement. In this case, it can be understood that the first core network device only serves the NTN. The registration process of the terminal device in the NTN can be shown in Figure 9a or Figure 9b.

[0167] In the process diagram shown in Figure 9a:

[0168] S901. The second core network device sends at least one equivalent public land mobile network (EPLMN) identifier to the terminal device.

[0169] In Figure 9a, the second core network device is the core network device with which the terminal device registers its PLMN. That is, during the process of registering with the TN, the terminal device can receive at least one EPLMN identifier sent by the second core network device of the TN. The at least one EPLMN identifier includes the PLMN identifier of the NTN.

[0170] Specifically, the terminal device sends a registration request message to the second core network device, and the registration request message is used to register the TN (which can be understood as registering in the PLMN of the TN network). The second core network device sends a registration acceptance message to the terminal device based on the contract information of the terminal device, and the registration acceptance message indicates receiving the registration request of the terminal device, and the registration acceptance message includes at least one EPLMN identifier, and the EPLMN identifier includes the PLMN identifier of the NTN (for example, when the contract information of the terminal device includes the NTN contract, the PLMN identifier includes the PLMN identifier of the NTN). Subsequently, when the terminal device needs to obtain NTN services, for example, when the terminal device moves to an area without coverage of the registered network, the terminal device performs a satellite operation and registers in the NTN based on the PLMN identifier of the NTN. The registration process in the NTN based on the PLMN identifier of the NTN may include any of the following methods one or two.

[0171] S902 (optional method 1): The terminal device sends a first message to the first core network device, where the first message is used to request registration.

[0172] That is, after the terminal device completes registration with the TN, if the terminal device needs to obtain NTN services, for example, if it moves to an area without TN coverage, the terminal device can send a first message requesting NTN registration to the first core network device through the NTN access network device. For a detailed description of the first message, please refer to the detailed description of the first message in S501 and will not be repeated here.

[0173] S903 (optional method 1): The terminal device receives a second message from the first core network device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0174] That is, after receiving the first message, the first core network device determines to accept the terminal device's registration request based on the terminal device's NTN subscription information. Furthermore, the first core network device sends a second message to the terminal device via the NTN access network device. For a detailed description of the second message, refer to the detailed description of the first message in S501 and are not repeated here.

[0175] S904 (optional method 2): The terminal device sends a first message to the first core network device through the second core network device, where the first message is used to request registration.

[0176] That is, after the terminal device completes registration in the TN, the terminal device can also send the first message to the second core network device through the TN access network device. Further, the second core network device forwards the first message to the first core network device. For a detailed description of the first message, please refer to the detailed description of the first message in S501, which will not be repeated here.

[0177] S905 (optional method 2): The terminal device receives a second message from the first core network device through the second core network device, where the second message indicates acceptance of the registration request of the terminal device.

[0178] That is, after the first core network device receives the first message, it determines to accept the terminal device's registration request based on the terminal device's NTN subscription information. Furthermore, the first core network device sends a second message to the second core network device, which in turn sends the second message to the TN access network device. The TN access network device then sends the second message to the terminal device. For a detailed description of the second message, refer to the detailed description of the second message in S502 and will not be repeated here.

[0179] In the flow diagram shown in FIG9b:

[0180] S911. The third core network device sends at least one EPLMN identifier to the terminal device.

[0181] In Figure 9b, the third core network device is the core network device used when the terminal device registers with the TN's PLMN. That is, during the terminal device's registration with the TN, it can receive at least one EPLMN identifier sent from the third core network device of the TN. The at least one EPLMN identifier includes the PLMN identifier of the NTN.

[0182] Specifically, the terminal device sends a registration request message to the third core network device, where the registration request message is used to register the TN. The third core network device sends a registration acceptance message to the terminal device based on the terminal device's subscription information. The registration acceptance message indicates receipt of the terminal device's registration request, and the registration acceptance message includes at least one EPLMN identifier, where the EPLMN identifier includes the PLMN identifier of the NTN. Subsequently, when the terminal device needs to obtain NTN services, for example, after leaving the coverage area of ​​the TN, the terminal device performs a satellite alignment operation and registers with the NTN based on the PLMN identifier of the NTN. The registration process in the NTN based on the PLMN identifier of the NTN may include either the following method 1 or method 2.

[0183] S912 (optional method one): the terminal device sends a first message to the first core network device, where the first message is used to request registration.

[0184] S913 (optional method 1): The terminal device receives a second message from the first core network device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0185] S914 (optional method 2): The terminal device sends a first message to the first core network device through the second core network device, where the first message is used to request registration.

[0186] S915 (optional method 2): The terminal device receives a second message from the first core network device through the second core network device, where the second message indicates acceptance of the registration request of the terminal device.

[0187] Among them, regarding the specific implementation of S912 to S915, reference can be made to the specific implementation of S902 to S905 in the aforementioned Figure 9a, which will not be repeated here. It should be noted that the difference between Figure 9a and Figure 9b is that: in Figure 9a, the second core network device in the second method (i.e., the TN core network device involved in S904 and S905 in Figure 9a) is the same as the core network device used when the terminal device registers the TN PLMN (i.e., the TN core network device involved in S901 in Figure 9a); while in Figure 9b, the second core network device in the second method (i.e., the TN core network device involved in S914 and S915 in Figure 9b) is different from the core network device used when the terminal device registers the TN PLMN (i.e., the TN core network device involved in S911 in Figure 9b).

[0188] Case 4: NTN and TN correspond to different access technologies under the same PLMN, for example, NTN and TN belong to the same operator. In this case, it can be understood that the first core network device can serve both NTN and TN at the same time, and the terminal device can be connected to the first core network device through NTN access or TN access. The registration process of the terminal device in NTN can be seen in Figure 10. Among them:

[0189] S1001: A terminal device sends a first message to a first core network device, where the first message is used to request registration. For an explanation of the first message, refer to the explanation of the first message in S501 above, which will not be repeated here.

[0190] Since the first core network device serves both the NTN and the TN, the terminal device can send a first message to the first core network device via the access network device (which can be either the NTN access network device or the TN access network device). The first message can be used to request registration with the NTN, or to request registration with both the TN and the NTN.

[0191] S1002: The terminal device receives a second message from the first core network device, the second message indicating that the first core network device accepts the registration request of the terminal device. For the description of the second message, please refer to the description of the second message in S502 above, which will not be repeated here.

[0192] Furthermore, the terminal device may receive the second message from the first core network device through an access network device (which may be an NTN access network device or a TN access network device).

[0193] In a possible implementation of the fourth situation, the period for the terminal device to initiate periodic registration to the first core network device in the first mode (i.e., the first period mentioned in this application) is greater than the period for the terminal device to initiate periodic registration to the first core network device after exiting the first mode (i.e., the period for the terminal device to initiate periodic registration in the TN, i.e., the second period mentioned in this application). It can be understood that the duration of the periodic timer configured by the first core network device for the terminal device in the first mode (such as the aforementioned first duration) is greater than the duration of the periodic timer configured by the first core network device for the terminal device exiting the first mode; or, the duration of the reachable timer corresponding to the terminal device in the first mode in the first core network device is greater than the duration of the reachable timer corresponding to the terminal device exiting the first mode in the first core network device; or, the duration of the implicit de-registration timer corresponding to the terminal device in the first mode in the first core network device is greater than the duration of the implicit de-registration timer corresponding to the terminal device exiting the first mode in the first core network device.

[0194] It is understandable that in order to implement the functions in the above embodiments, the terminal device includes hardware structures and / or software modules corresponding to the execution of each function. It should be readily apparent to those skilled in the art that, in combination with the units and method steps of the various examples described in the embodiments disclosed in this application, this application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software transceiver components driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0195] Figures 11 and 12 are schematic diagrams of the structures of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal device in the above-mentioned method embodiments, and thus can also achieve the beneficial effects possessed by the above-mentioned method embodiments. In the embodiments of the present application, the communication device can be a terminal device, or a module (such as a chip) applied to the terminal device, or the communication device can be a first core network device, or a module (such as a chip) applied to the first core network device.

[0196] As shown in Figure 11, a communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the functions of the terminal device in the method embodiment of any of Figures 4 and 7 to 10, or to implement the functions of the first core network device in the method embodiment of any of Figures 4 and 7 to 10.

[0197] When the communication device 1100 is used to implement the functions of the terminal device in the embodiment of the present application: when the terminal device completes registration in the non-terrestrial network NTN, the processing unit 1110 is used to control the terminal device to enter the first mode; wherein, the terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode.

[0198] In one possible implementation, the transceiver unit 1120 is used to send a first message to the first core network device, where the first message is used to request registration; the transceiver unit 1120 is also used to receive a second message from the first core network device, where the second message indicates that the first core network device accepts the registration request of the terminal device.

[0199] In a possible implementation, the first message includes first information, where the first information indicates that the terminal device cannot guarantee to perform periodic registration, or the first information indicates that the terminal device requests not to perform periodic registration.

[0200] In one possible implementation, the first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability to support NTN communication, and the second capability information indicates whether the terminal device has the capability to automatically point to the satellite.

[0201] In a possible implementation, the second message includes second information, where the second information indicates that after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN.

[0202] In a possible implementation, the second message also includes third information, which indicates a first duration, where the first duration is the duration of the periodic registration timer, and the first duration is related to the duration of the NTN service contract signed by the terminal device; the aforementioned terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode, including: the terminal device does not need to initiate periodic registration with the first core network device of the NTN within the first duration in the first mode.

[0203] In a possible implementation, the third information indicates that the periodic registration timer is not activated.

[0204] In a possible implementation, the processing unit 1110 is configured to control the terminal device to maintain a registered state and / or to maintain a no-service state in the first mode.

[0205] In a possible implementation, the terminal device does not need to monitor the paging message from the NTN in the first mode.

[0206] In one possible implementation, when the terminal device is registered and a first condition is satisfied, the processing unit 1110 is configured to control the terminal device to enter the first mode; wherein the first condition includes at least one of the following:

[0207] The terminal device completes data transmission via NTN;

[0208] The terminal device transitions from the connection management (CM) connected state to the CM idle state;

[0209] The terminal device switches from a first state to a second state, wherein in the first state the terminal device can communicate with the NTN satellite and in the second state the terminal device cannot communicate with the NTN satellite; or,

[0210] The terminal equipment stops using NTN services.

[0211] In one possible implementation, the terminal device converts from the connection management CM connected state to the CM idle state, including: the terminal device converts from the CM connected state to the CM idle state, and the duration of the terminal device in the CM idle state is greater than a second duration, and the second duration is greater than 0.

[0212] In one possible implementation, after the terminal device enters the first mode, when the terminal device switches from the second state to the first state, the terminal transceiver unit 1120 is used to send a first message to the first core network device; wherein the first message is used to request registration or request service; in the first state, the terminal device can communicate with the NTN satellite, and in the second state, the terminal device cannot communicate with the NTN satellite.

[0213] In one possible implementation, when a second condition is met, the processing unit 1110 is configured to control the terminal device to exit the first mode; wherein the second condition includes at least one of the following: the terminal device transitions from the second state to the first state, wherein the terminal device can communicate with the NTN satellite in the first state, and cannot communicate with the NTN satellite in the second state; the terminal device transitions from the CM idle state to the CM connected state; or the terminal device detects that a satellite pointing operation is being performed.

[0214] In a possible implementation, the first core network device only serves the NTN, or the first core network device serves the NTN and the TN.

[0215] In one possible implementation, the first core network device only serves NTN; the transceiver unit 1120 is used to send a first message to the first core network device through the second core network device of TN; the transceiver unit 1120 is used to receive a second message from the first core network device through the second core network device.

[0216] In a possible implementation, the first message further includes a preference for the first mode; and the second message further includes information confirming acceptance of the preference.

[0217] In a possible implementation, when the terminal device does not have the capability of automatic pointing, or the terminal device is selected to perform the pointing operation using manual pointing, the first message further includes a preference for the first mode.

[0218] In a possible implementation, the transceiver unit 1120 is configured to receive at least one equivalent public land mobile network EPLMN identifier from the second core network device, where the at least one EPLMN identifier includes a public land mobile network PLMN identifier of the NTN.

[0219] In one possible implementation, the transceiver unit 1120 is used to receive at least one equivalent public land mobile network EPLMN identifier from a third core network device, where the at least one EPLMN identifier includes the public land mobile network PLMN identifier of the NTN. The third core network device is the core network device for registering the PLMN of the terminal device.

[0220] In one possible implementation, a terminal device includes a first SIM card and a second SIM card; the first SIM card is subscribed to a TN service, and the second SIM card is subscribed to an NTN service; the second SIM card sends a first message to the first SIM card; the first SIM card sends the first message to an access network device of the TN; the first SIM card receives a second message from the access network device; and the first SIM card sends the second message to the second SIM card.

[0221] For a more detailed description of the above-mentioned transceiver unit 1120 and processing unit 1110, please refer to the relevant description of the terminal device in the embodiment of the present application.

[0222] When the communication device 1100 is used to implement the function of the first core network device in the embodiment of the present application: when the terminal device completes registration in the non-terrestrial network NTN, the processing unit 1110 is used to determine that the terminal device enters the first mode; wherein, the terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode.

[0223] In one possible implementation, the transceiver unit 1120 is used to receive a first message from the terminal device, where the first message is used to request registration; the transceiver unit 1120 is also used to send a second message to the terminal device, where the second message instructs the first core network device to accept the registration request of the terminal device.

[0224] In a possible implementation, the first message includes first information, where the first information indicates that the terminal device cannot guarantee to perform periodic registration, or the first information indicates that the terminal device requests not to perform periodic registration.

[0225] In one possible implementation, the first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability to support NTN communication, and the second capability information indicates whether the terminal device has the capability to automatically point to the satellite.

[0226] In one possible implementation, the processing unit 1110 is further configured to determine a second message based on the first information; wherein the second message indicates at least one of the following:

[0227] Whether to receive preferred information;

[0228] Whether the periodic registration timer is activated;

[0229] If the periodic registration timer is activated, the duration of the periodic registration timer; or

[0230] Whether to perform implicit deregistration on the terminal device.

[0231] In a possible implementation, the second message includes second information, where the second information indicates that after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN.

[0232] In a possible implementation, the second message also includes third information, which indicates a first duration, where the first duration is the duration of the periodic registration timer, and the first duration is related to the duration of the NTN service contracted by the terminal device; the aforementioned terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode, including: the terminal device does not need to initiate periodic registration with the first core network device of the NTN within the first duration in the first mode.

[0233] In a possible implementation, the third information indicates that the periodic registration timer is not activated.

[0234] In a possible implementation, the first core network device keeps the terminal device in the first mode in a registered state and / or keeps it out of service.

[0235] In a possible implementation, the first core network device does not need to send a paging message to the terminal device in the first mode.

[0236] In one possible implementation, when the terminal device completes registration in the non-terrestrial network NTN and satisfies a third condition, the processing unit 1110 is further configured to determine whether the terminal device enters the first mode; wherein the third condition includes one or more of the following:

[0237] The terminal device transitions from the connection management (CM) connected state to the CM idle state;

[0238] The terminal device does not use NTN's network services within the third time period, and the third time period is greater than 0; or

[0239] When the first core network device fails to page the terminal device.

[0240] In one possible implementation, the terminal device converts from the connection management CM connected state to the CM idle state, including: the terminal device converts from the CM connected state to the CM idle state, and the duration of the terminal device in the CM idle state is greater than the second duration, and the second duration is greater than 0.

[0241] In a possible implementation, after determining that the terminal device enters the first mode, the transceiver unit 1120 is configured to receive a first message from the terminal device, where the first message is used to request registration or service.

[0242] In one possible implementation, when the fourth condition is met, the processing unit 1110 is also used to determine whether the terminal device exits the first mode; wherein the fourth condition includes at least one of the following: the first core network device receives a first message from the terminal device, and the first message is used to request registration or request service; or, the terminal device switches from a CM idle state to a CM connected state.

[0243] In a possible implementation, the first core network device only serves the NTN, or the first core network device serves the NTN and the TN.

[0244] In one possible implementation, the first core network device only serves NTN; the transceiver unit 1120 is also used to receive a first message from the terminal device through the second core network device of TN; the transceiver unit 1120 is also used to send a second message to the terminal device through the second core network device.

[0245] In a possible implementation, the first message further includes a preference for the first mode; and the second message further includes information confirming acceptance of the preference.

[0246] For a more detailed description of the above-mentioned transceiver unit 1120 and processing unit 1110, please refer to the relevant description of the first core network device in the embodiment of the present application.

[0247] As shown in Figure 12, communication device 1200 includes a processor 1210 and an interface circuit 1220. Processor 1210 and interface circuit 1220 are coupled to each other. It is understood that interface circuit 1220 may be a transceiver or an input / output interface. Optionally, communication device 1200 may further include a memory 1230 for storing instructions executed by processor 1210, input data required by processor 1210 to execute instructions, or data generated by processor 1210 after executing instructions.

[0248] When the communication device 1200 is used to implement the method shown in the diagram of the embodiment of the present application, the processor 1210 is used to implement the functions of the above-mentioned processing unit 1110, and the interface circuit 1220 is used to implement the functions of the above-mentioned transceiver unit 1120.

[0249] When the above-mentioned communication device is a chip applied to a terminal device, the terminal chip implements the functions of the terminal device in the above-mentioned method embodiment. When the terminal chip receives information from the base station, it can be understood that the information is first received by other modules in the terminal device (such as a radio frequency module or antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to the base station, it can be understood that the information is first sent to other modules in the terminal device (such as a radio frequency module or antenna) and then sent to the base station by these modules.

[0250] When the communication device is a chip implemented in a first core network device, the chip implements the functions of the first core network device in the above-described method embodiment. When the first core network device chip receives information from a terminal device, it can be understood that the information is first received by other modules in the first core network device (such as a radio frequency module or antenna) and then transmitted to the first core network device chip by these modules. When the first core network device chip sends information to a terminal, it can be understood that the information is transmitted to other modules in the network device (such as a radio frequency module or antenna) and then transmitted to the terminal by these modules.

[0251] In this application, when entity A sends information to entity B, it can be done directly from A to B or indirectly through another entity. Similarly, when entity B receives information from entity A, it can be done directly from entity B or indirectly through another entity. Entities A and B herein can be RAN nodes or terminals, or modules within a RAN node or terminal. The sending and receiving of information can be information exchange between a RAN node and a terminal, for example, between a base station and a terminal; the sending and receiving of information can also be information exchange between two RAN nodes, for example, between a CU and a DU; the sending and receiving of information can also be information exchange between different modules within a device, for example, between a terminal chip and other modules in the terminal, or between a base station chip and other modules within the base station.

[0252] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0253] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0254] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0255] In the various embodiments of this application, unless otherwise specified or logically conflicting, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. The combined technical solutions are also within the scope of this application.

[0256] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0257] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A method, characterized in that The method comprises: When the terminal device completes registration in the non-terrestrial network NTN, the terminal device enters the first mode; Wherein, the terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode; The terminal device is registered in the non-terrestrial network NTN, including: The terminal device sends a first message to the first core network device, where the first message is used to request registration; The terminal device receives a second message from the first core network device, and the second message indicates that the first core network device accepts the registration request of the terminal device.

2. The method according to claim 1, characterized in that: The first message includes first information; wherein, The first information indicates that the terminal device cannot guarantee to perform periodic registration, or, The first information indicates that the terminal device requests not to perform periodic registration.

3. The method according to claim 2, characterized in that: The first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability of supporting NTN communication, and the second capability information indicates whether the terminal device has the capability of automatic satellite alignment.

4. The method according to any one of claims 1 to 3, characterized in that: The second message includes second information, and the second information indicates that after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN; or, The second message includes third information, the third information indicates a first duration, the first duration is the duration of the periodic registration timer, and the first duration is related to the duration of the NTN service contracted by the terminal device; The terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode, including: the terminal device does not need to initiate periodic registration with the first core network device of the NTN within the first time period in the first mode; or, The second message includes third information, and the third information indicates that the periodic registration timer is not activated.

5. The method according to any one of claims 1 to 4, characterized in that: The terminal device remains in a registered state and / or remains out of service in the first mode; And / or, the terminal device does not need to monitor a paging message from the NTN in the first mode.

6. The method according to any one of claims 1 to 5, characterized in that: When the terminal device completes registration in the non-terrestrial network NTN, the terminal device enters the first mode, including: when the terminal device completes registration and satisfies a first condition, the terminal device enters the first mode; Wherein, the first condition includes at least one of the following: The terminal device completes data transmission via the NTN; The terminal device is converted from a connection management CM connected state to a CM idle state; The terminal device is converted from a first state to a second state, in which the terminal device can communicate with the satellite of the NTN and in which the terminal device cannot communicate with the satellite of the NTN; or, The terminal device stops using the service of the NTN.

7. The method according to claim 6, characterized in that: The terminal device is converted from the connection management CM connected state to the CM idle state, including: the terminal device is converted from the CM connected state to the CM idle state, and the duration of the terminal device being in the CM idle state is greater than a second duration, and the second duration is greater than 0.

8. The method according to any one of claims 1 to 7, characterized in that After the terminal device enters the first mode, the method includes: When the terminal device is converted from the second state to the first state, the terminal device sends a first message to the first core network device; The first message is used to request registration or service; in the first state, the terminal device can communicate with the satellite of the NTN, and in the second state, the terminal device cannot communicate with the satellite of the NTN.

9. The method according to any one of claims 1 to 8, characterized in that: The method further comprises: When a second condition is met, the terminal device exits the first mode; wherein the second condition includes at least one of the following: The terminal device is converted from a second state to a first state, in which the terminal device can communicate with the satellite of the NTN, and in which the terminal device cannot communicate with the satellite of the NTN; The terminal device is converted from the CM idle state to the CM connected state; or, The terminal device detects that a satellite alignment operation is performed.

10. The method according to any one of claims 1 to 9, characterized in that: The first core network device only serves the NTN, or the first core network device serves the NTN and the terrestrial network TN.

11. The method according to any one of claims 1 to 10, characterized in that: The first message also includes a preference for the first mode; the second message also includes information confirming acceptance of the preference.

12. The method according to any one of claims 1 to 11, characterized in that: In the case that the terminal device does not have the capability of automatic alignment, or the terminal device is selected to use manual alignment to perform the alignment operation, the first message further includes a preference for the first mode.

13. The method according to any one of claims 1 to 12, characterized in that: The method further comprises: The terminal device receives at least one equivalent public land mobile network EPLMN identifier from the second core network device, and the at least one EPLMN identifier includes a public land mobile network PLMN identifier of the NTN.

14. The method according to any one of claims 1 to 13, characterized in that: The method further comprises: The terminal device receives at least one equivalent public land mobile network EPLMN identifier from a third core network device, wherein the at least one EPLMN identifier includes a public land mobile network PLMN identifier of the NTN, and the third core network device is a core network device for registering the PLMN for the terminal device.

15. The method according to any one of claims 1 to 14, characterized in that: The first core network device only serves the NTN; The terminal device sending the first message to the first core network device includes: the terminal device sending the first message to the first core network device through the second core network device of the land network TN; The terminal device receives the second message from the first core network device, including: the terminal device receives the second message from the first core network device through the second core network device.

16. The method according to claim 15, characterized in that: The terminal device includes a first subscriber identity module SIM card and a second SIM card; the first SIM card subscribes to the TN service, and the second SIM card subscribes to the NTN service; the method further includes: The second SIM card sends a first message to the first SIM card; The first SIM card sends the first message to the access network device of the TN; The first SIM card receives a second message from the access network device of the TN; The first SIM card sends the second message to the second SIM card.

17. A method, characterized in that The method comprises: When the terminal device completes registration in the non-terrestrial network NTN, the first core network device of the NTN determines that the terminal device enters the first mode; Wherein, the terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode; The terminal device is registered in the non-terrestrial network NTN, including: The first core network device receives a first message from the terminal device, where the first message is used to request registration; The first core network device sends a second message to the terminal device, and the second message indicates that the first core network device accepts the registration request of the terminal device.

18. The method according to claim 17, characterized in that: The first message includes first information; wherein, The first information indicates that the terminal device cannot guarantee to perform periodic registration, or, The first information indicates that the terminal device requests not to perform periodic registration.

19. The method according to claim 18, characterized in that: The first information includes first capability information and / or second capability information; wherein the first capability information indicates whether the terminal device has the capability of supporting NTN communication, and the second capability information indicates whether the terminal device has the capability of automatic satellite alignment.

20. The method according to claim 18 or 19, characterized in that: The method further comprises: The first core network device determines at least one of the following according to the first information: Whether to accept the information of the stated preferences; Whether the periodic registration timer is activated; When the periodic registration timer is activated, the duration of the periodic registration timer; or Whether to perform implicit deregistration on the terminal device.

21. The method according to any one of claims 17 to 20, characterized in that: The second message includes second information, and the second information indicates that after the terminal device enters the first mode, it is not necessary to initiate periodic registration with the first core network device of the NTN; or, The second message further includes third information, where the third information indicates a first duration, where the first duration is the duration of a periodic registration timer, and the first duration is related to the duration of a contract for an NTN service signed by the terminal device; The terminal device does not need to initiate periodic registration with the first core network device of the NTN in the first mode, including: the terminal device does not need to initiate periodic registration with the first core network device of the NTN within the first time period in the first mode; or, The third information indicates that the periodic registration timer is not activated.

22. The method according to any one of claims 17 to 21, characterized in that: The first core network device keeps the terminal device in the first mode in a registered state and / or out of service; Alternatively, the first core network device does not need to send a paging message to the terminal device in the first mode.

23. The method according to any one of claims 17 to 22, characterized in that: When the terminal device completes registration in the non-terrestrial network NTN, the first core network device of the NTN determines that the terminal device enters the first mode, including: when the terminal device completes registration in the non-terrestrial network NTN and satisfies the third condition, the first core network device of the NTN determines that the terminal device enters the first mode; The third condition includes one or more of the following: The terminal device is converted from a connection management CM connected state to a CM idle state; The terminal device does not use the network service of NTN within a third time period, and the third time period is greater than 0; or, When the first core network device fails to page the terminal device.

24. The method according to claim 23, characterized in that: The terminal device is converted from a connection management CM connected state to a CM idle state, including: The terminal device is converted from the CM connected state to the CM idle state, and the duration of the terminal device being in the CM idle state is greater than a second duration, and the second duration is greater than 0.

25. The method according to any one of claims 23 or 24, characterized in that After the first core network device determines that the terminal device enters the first mode, the method further includes: The first core network device receives the first message from the terminal device, where the first message is used to request registration or request service.

26. The method according to any one of claims 17 to 25, characterized in that: The method further comprises: When the fourth condition is met, the first core network device determines that the terminal device exits the first mode; The fourth condition includes one or more of the following: The first core network device receives a first message from the terminal device, where the first message is used to request registration or service; Alternatively, the terminal device switches from the CM idle state to the CM connected state.

27. The method according to any one of claims 17 to 26, characterized in that: The first core network device only serves NTN, or the first core network device serves NTN and TN.

28. The method according to any one of claims 17 to 27, characterized in that: The first core network device only serves the NTN; The first core network device receiving the first message from the terminal device includes: the first core network device receiving the first message from the terminal device through the second core network device of the TN; The first core network device sends the second message to the terminal device, including: the first core network device sends the second message to the terminal device through the second core network device.

29. The method according to any one of claims 17 to 28, characterized in that: The first message also includes a preference for the first mode; the second message also includes information confirming acceptance of the preference.

30. A communication device, characterized in that: It includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor, or send signals from the processor to other communication devices outside the communication device, and the processor implements the method as described in any one of claims 1 to 16 or the method as described in any one of claims 17 to 29 through a logic circuit or executing code instructions.

31. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instructions, and when the computer program or instructions are executed by the communication device, the method according to any one of claims 1 to 16, or the method according to any one of claims 17 to 29 is implemented.

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