A communication method, a communication device, and a communication system

Abstract

The application provides a communication method, a communication device and a communication system. The method comprises: determining sleep time information of a terminal device according to satellite coverage information of the terminal device, wherein the satellite coverage information indicates a time period during which the terminal device is covered by a satellite network and / or a time period during which the terminal device is not covered by the satellite network, and the sleep time information corresponds to a sleep time period, which comprises the time period during which the terminal device is not covered by the satellite network; and sending the sleep time information to the terminal device. According to the scheme, the sleep time information is determined according to the satellite coverage information of the terminal device, and the sleep time period corresponding to the sleep time information comprises the time period during which the terminal device is not covered by the satellite network, so that the terminal device can be ensured to sleep as much as possible during the time period during which the terminal device is not covered by the satellite network, unnecessary cell selection and other network connection operations are avoided, and the energy consumption of the terminal device is saved.

Description

[0001] This application is a divisional application. The original application has the application number 202111308873.5 and the original application date is November 5, 2021. The entire contents of the original application are incorporated herein by reference.

[0002] This application claims priority to Chinese Patent Application No. 202111178674.7, filed on October 10, 2021, entitled "A Communication Method, Communication Device and Communication System", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method, communication device and communication system. Background Technology

[0004] Currently, in some communication scenarios, such as massive machine-type communications (mMTC) applications, satellite communication has been introduced to ensure network coverage for terminal devices. Satellite communication can enhance network coverage to a certain extent.

[0005] However, since satellites are in motion, there may be periods when terminal devices are not covered by the satellite network. Summary of the Invention

[0006] This application provides a communication method, communication device, and communication system for reducing the energy consumption of terminal equipment or core network equipment (such as mobility management network elements) in satellite communication scenarios.

[0007] In a first aspect, embodiments of this application provide a communication method, which can be executed by a mobility management network element or a module (such as a chip) applied in a mobility management network element. The method includes: determining sleep time information of a terminal device based on satellite coverage information, wherein the satellite coverage information indicates the time period during which the terminal device is covered by a satellite network and / or the time period during which it is not covered by a satellite network, and the sleep time period corresponding to the sleep time information includes the time period during which the terminal device is not covered by a satellite network; and sending the sleep time information to the terminal device.

[0008] In the above scheme, the mobility management network element determines the sleep time information based on the satellite coverage information of the terminal device. The sleep time period corresponding to this sleep time information includes the time period when the terminal device is not covered by the satellite network, thereby ensuring that the terminal device can sleep as much as possible during the time period when it is not covered by the satellite network, avoiding unnecessary network connection operations such as cell selection, and saving the power consumption of the terminal device.

[0009] In one possible implementation, one or more of the eDRX cycle, periodic TAU cycle, or periodic registration cycle of the terminal device are determined based on the satellite coverage information; wherein the hibernation time information includes a hibernation start time, which is located within the eDRX cycle or the periodic TAU cycle.

[0010] In one possible implementation, the hibernation time information includes the hibernation start time and hibernation end time; or, the hibernation time information includes the hibernation start time and hibernation duration.

[0011] The above solution ensures that the terminal device will remain in sleep mode during the sleep period corresponding to the sleep time information, and will not perform any services, including not performing periodic TAU, not performing periodic registration, and not performing uplink data transmission, which can reduce the power consumption of the terminal device.

[0012] In one possible implementation, the satellite coverage information is received; or, the ephemeris information of the satellite cell where the terminal device is located is received, and the satellite coverage information is determined based on the ephemeris information.

[0013] In one possible implementation, the location of the terminal device is determined to be fixed or its movement trajectory is determined to be fixed.

[0014] In one possible implementation, when the deregistration timer corresponding to the terminal device times out, it is determined based on the satellite coverage information that the terminal device is not covered by the satellite network, and therefore deregistration is not performed on the terminal device.

[0015] According to this scheme, when a terminal device is not covered by a satellite network, the mobility management network element will not register the terminal device. This can reduce the number of times the terminal device switches between registration and deregistration, thereby reducing the energy consumption of the terminal device and reducing the frequency of signaling interactions with the network.

[0016] Secondly, embodiments of this application provide a communication method, which can be executed by a mobility management network element or a module (such as a chip) applied in a mobility management network element. The method includes: when a deregistration timer corresponding to a terminal device times out, determining, based on the satellite coverage information of the terminal device, that the terminal device is not covered by a satellite network, wherein the satellite coverage information indicates the time period during which the terminal device is covered by a satellite network and / or the time period during which it is not covered by a satellite network; and in response to the terminal device not being covered by a satellite network, determining not to perform deregistration on the terminal device.

[0017] According to this scheme, when a terminal device is not covered by a satellite network, the mobility management network element does not register the terminal device, which reduces the number of times the terminal device switches between registration and deregistration, thereby reducing the power consumption of the terminal device. In one possible implementation, a first message is sent to the terminal device, indicating that the terminal device should perform uplink transmission according to the satellite network coverage when it has uplink transmission needs.

[0018] In one possible implementation, the first information is the satellite coverage information; specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0019] In one possible implementation, the satellite coverage information is sent to the terminal device; specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0020] In one possible implementation, the uplink transmission requirement includes one or more of periodic TAU, periodic registration, or uplink data transmission.

[0021] In one possible implementation, the satellite coverage information is received; or, the ephemeris information of the satellite cell where the terminal device is located is received, and the satellite coverage information is determined based on the ephemeris information.

[0022] In one possible implementation, the location of the terminal device is determined to be fixed or its movement trajectory is determined to be fixed.

[0023] Thirdly, embodiments of this application provide a communication method, which can be executed by a mobility management network element or a module (such as a chip) applied in a mobility management network element. The method includes: determining satellite coverage information of a terminal device, the satellite coverage information indicating the time period during which the terminal device is covered by a satellite network and / or the time period during which it is not covered by a satellite network; and determining a maximum waiting time based on the satellite coverage information, the maximum waiting time indicating the maximum achievable duration of waiting for the terminal device.

[0024] According to the above scheme, the mobility management network element can determine the reachability based on the satellite coverage information of the terminal device. If the terminal device is unreachable, the maximum waiting time is determined based on the satellite coverage information to ensure that the terminal device is not paged when it is not covered by the satellite network. This can reduce unnecessary signaling interactions between the mobility management network element and the access network device, and at the same time avoid the waste of paging resources of the access network device and the loss of downlink data of the terminal device.

[0025] In one possible implementation, the terminal device is determined to be unreachable based on the satellite coverage information.

[0026] In one possible implementation, the satellite coverage information is received.

[0027] In one possible implementation, the ephemeris information of the satellite cell where the terminal device is located is received; and the satellite coverage information is determined based on the ephemeris information.

[0028] In one possible implementation, a paging message is sent to the access network device. This paging message includes the identification information of the terminal device and indicates that the terminal device is being paged. A first message is received from the access network device. This first message includes a paging failure indication and satellite coverage information. The paging failure indication indicates that the paging failure is due to lack of satellite network coverage. Optionally, the paging failure indication further indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0029] In one possible implementation, a paging message is sent to the access network device, the paging message including the identification information of the terminal device, the paging message indicating that the terminal device is being paged; a first message is received from the access network device, the first message including the satellite coverage information of the terminal device, the satellite coverage information indicating that the paging failure is due to lack of satellite network coverage, optionally, the satellite coverage information also indicating that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0030] In one possible implementation, the location of the terminal device is determined to be fixed or its movement trajectory is determined to be fixed.

[0031] Fourthly, embodiments of this application provide a communication method, which can be executed by a terminal device or a module (such as a chip) applied in the terminal device. The method includes: receiving first information, the first information indicating that the terminal device, when it has an uplink transmission requirement, will perform uplink transmission according to satellite network coverage; when there is an uplink transmission requirement, based on the first information, determining that the terminal device is not covered by a satellite network, and then determining not to perform uplink transmission.

[0032] According to the above scheme, when the terminal device is not covered by the satellite network, it will not perform uplink transmission even if there is an uplink transmission requirement. This can avoid unnecessary network connection operations such as cell scanning and cell selection, thereby saving the energy consumption of the terminal device.

[0033] In one possible implementation, the first information is satellite coverage information, which indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0034] In one possible implementation, satellite coverage information is received, which indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; the first information is specifically used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0035] In one possible implementation, the uplink transmission requirement includes one or more of periodic TAU, periodic registration, or uplink data transmission.

[0036] Fifthly, embodiments of this application provide a communication method, which can be executed by a terminal device or a module (such as a chip) applied in the terminal device. The method includes: receiving sleep time information, wherein the sleep time information corresponds to a sleep period including a period during which the terminal device is not covered by a satellite network, the sleep time information being determined based on the satellite coverage information of the terminal device, the satellite coverage information indicating the period during which the terminal device is covered by a satellite network and / or the period during which it is not covered by a satellite network; and performing sleep mode based on the sleep time information.

[0037] The above solution allows terminal devices to hibernate during periods when they are not covered by the satellite network, avoiding unnecessary network connection operations such as cell scanning and cell selection, thereby saving energy consumption of the terminal devices.

[0038] In one possible implementation, the sleep time information includes a sleep start time, which is located within the eDRX cycle of the terminal device, the periodic TAU cycle of the terminal device, or the periodic registration cycle of the terminal device.

[0039] In one possible implementation, the hibernation time information includes the hibernation start time and hibernation end time; or, the hibernation time information includes the hibernation start time and hibernation duration.

[0040] Sixthly, embodiments of this application provide a communication method, which can be executed by an access network device or a module (such as a chip) applied in the access network device. The method includes: acquiring satellite coverage information or ephemeris information of a satellite cell, the satellite coverage information indicating the time period during which the satellite cell is covered by a satellite network and / or the time period during which it is not covered by a satellite network; and sending the satellite coverage information or ephemeris information of the satellite cell to a mobility management network element.

[0041] In one possible implementation, during the N2 interface establishment process, satellite coverage information or ephemeris information corresponding to the satellite cell of the access network device is sent to the mobility management network element.

[0042] In one possible implementation, during the registration process of the terminal device, satellite coverage information or ephemeris information of the satellite cell where the terminal device is located is sent to the mobility management network element.

[0043] In one possible implementation, a paging message is received from the mobility management network element. The paging message includes identification information of the terminal device and indicates that the terminal device is being paged. Based on the satellite coverage information of the satellite cell where the terminal device is located, it is determined that the satellite cell has no network coverage. A first message is then sent to the mobility management network element. The first message includes a paging failure indication and the satellite coverage information of the satellite cell where the terminal device is located. The paging failure indication is used to indicate that the paging failure is due to lack of satellite network coverage. Optionally, the paging failure indication also indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0044] In one possible implementation, a paging message is received from the mobility management network element. The paging message includes identification information of the terminal device and indicates that the terminal device is being paged. Based on the satellite coverage information of the satellite cell where the terminal device is located, it is determined that the satellite cell has no network coverage. A first message is then sent to the mobility management network element. The first message includes the satellite coverage information of the satellite cell where the terminal device is located. The satellite coverage information of the satellite cell where the terminal device is located is the satellite coverage information of the terminal device. The satellite coverage information is used to indicate that the reason for the paging failure is that the device is not covered by the satellite network. Optionally, the satellite coverage information also indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0045] In a seventh aspect, embodiments of this application provide a communication method, which can be executed by a mobility management network element or a module (such as a chip) applied in a mobility management network element. The method includes: determining a periodic TAU period of the terminal device based on satellite coverage information of the terminal device, and sending the periodic TAU period to the terminal device; or, determining a periodic registration period of the terminal device based on satellite coverage information of the terminal device, and sending the periodic registration period to the terminal device; wherein the satellite coverage information indicates the time period during which the terminal device is covered by a satellite network and / or the time period during which it is not covered by a satellite network.

[0046] In the above scheme, the mobility management network element determines the periodic TAU period or periodic registration period based on the satellite coverage information of the terminal device. This ensures that the time period corresponding to the periodic TAU period or the periodic registration period includes the time period when the terminal device is not covered by the satellite network. This ensures that the terminal device can avoid performing the periodic TAU process or periodic registration process as much as possible during the time period when it is not covered by the satellite network, thereby avoiding unnecessary network connection operations such as cell selection and saving the terminal device's energy consumption.

[0047] In one possible implementation, the time period corresponding to the periodic TAU period includes the time period during which the terminal device is not covered by the satellite network; or, the time period corresponding to the periodic registration period includes the time period during which the terminal device is not covered by the satellite network.

[0048] In one possible implementation, based on the satellite coverage information, an instruction message is sent to the access network device, which instructs the access network device to perform the terminal device release procedure.

[0049] In one possible implementation, a first duration is determined based on the satellite coverage information of the terminal device. This first duration is the duration after the terminal device enters an idle state and before it enters a sleep state. The first duration is then sent to the terminal device.

[0050] In one possible implementation, a cause value is sent to the terminal device, which is satellite discontinuous coverage.

[0051] In one possible implementation, the reason value is also used to instruct the terminal device not to perform uplink transmissions during sleep.

[0052] In one possible implementation, a GUTI reallocation command is sent to the terminal device, the GUTI reallocation command including the periodic TAU period; or, a TAU acceptance message is sent to the terminal device, the TAU acceptance message including the periodic TAU period.

[0053] In one possible implementation, a configuration update command is sent to the terminal device, the configuration update command including the periodic registration period; or, a mobile registration update acceptance message is sent to the terminal device, the mobile registration update acceptance message including the periodic registration period.

[0054] Eighthly, embodiments of this application provide a communication method, which can be executed by a terminal device or a module (such as a chip) applied in the terminal device. The method includes: receiving a periodic TAU period from a mobility management network element, and performing a periodic TAU according to the periodic TAU period, wherein the time period corresponding to the periodic TAU period includes a time period during which the terminal device is not covered by a satellite network; or, receiving a periodic registration period from a mobility management network element, and performing a periodic registration according to the periodic registration period, wherein the time period corresponding to the periodic registration period includes a time period during which the terminal device is not covered by a satellite network.

[0055] The above scheme ensures that the time period corresponding to the periodic TAU cycle or the periodic registration cycle received by the terminal device includes the time period when the terminal device is not covered by the satellite network. This ensures that the terminal device can avoid performing the periodic TAU process or the periodic registration process as much as possible during the time period when it is not covered by the satellite network, thereby avoiding unnecessary network connection operations such as cell selection and saving the terminal device's energy consumption.

[0056] In one possible implementation, the periodic TAU period or the periodic registration period is determined based on the satellite coverage information of the terminal device, which indicates the time periods during which the terminal device is covered by the satellite network and / or the time periods during which it is not covered by the satellite network.

[0057] In one possible implementation, before receiving a periodic TAU period from the mobility management network element, a TAU request is sent to the mobility management network element based on the satellite coverage information of the terminal device; or, before receiving a periodic registration period from the mobility management network element, a mobile registration update request is sent to the mobility management network element based on the satellite coverage information of the terminal device; wherein the satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network.

[0058] In one possible implementation, a first duration is received from the mobility management network element. This first duration is the duration after the terminal device enters the idle state and before it enters the sleep state. The first duration is determined based on the satellite coverage information of the terminal device.

[0059] In one possible implementation, a cause value is received from the mobility management network element, where the cause value is satellite discontinuous coverage.

[0060] In one possible implementation, the cause value is used to instruct the terminal device not to perform uplink transmission during sleep; when there is an uplink transmission requirement, it is determined not to perform uplink transmission based on the cause value.

[0061] Ninthly, embodiments of this application provide a communication method, which can be executed by an access network device or a module (such as a chip) applied in the access network device. The method includes: sending a context release request to a mobility management network element (MLE) based on satellite coverage information of a terminal device, the context release request being used to request the MLE to release the context of the terminal device, the satellite coverage information indicating the time period during which the terminal device is covered by a satellite network and / or the time period during which it is not covered by a satellite network; receiving a periodic TAU period from the MLE and sending the periodic TAU period to the terminal device, the time period corresponding to the periodic TAU period including the time period during which the terminal device is not covered by a satellite network; or, receiving a periodic registration period from the MLE and sending the periodic registration period to the terminal device, the time period corresponding to the periodic registration period including the time period during which the terminal device is not covered by a satellite network.

[0062] In a tenth aspect, embodiments of this application provide a communication device, which may be a mobility management network element or a module (such as a chip) applied in a mobility management network element. The device has the function of implementing any of the implementation methods of the first to third and seventh aspects described above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0063] Eleventhly, embodiments of this application provide a communication device, which may be a terminal device or a module (such as a chip) applied in a terminal device. The device has the function of implementing any of the methods described in the fourth, fifth, or eighth aspects above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0064] In a twelfth aspect, embodiments of this application provide a communication device, which may be an access network device or a module (such as a chip) applied in an access network device. The device has the function of implementing any of the methods described in the sixth or ninth aspect above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions.

[0065] In a thirteenth aspect, embodiments of this application provide a communication device, including a processor and a memory; the memory is used to store computer instructions, and when the device is running, the processor executes the computer instructions stored in the memory to cause the device to perform any of the implementation methods in the first to ninth aspects described above.

[0066] In a fourteenth aspect, embodiments of this application provide a communication apparatus including units or means for performing various steps of any of the implementation methods in the first to ninth aspects described above.

[0067] In a fifteenth aspect, embodiments of this application provide a communication device, including a processor and an interface circuit. The processor is configured to communicate with other devices via the interface circuit and execute any of the implementation methods described in the first to ninth aspects. The processor may include one or more devices.

[0068] In a sixteenth aspect, embodiments of this application provide a communication device including a processor coupled to a memory, the processor being configured to invoke a program stored in the memory to execute any of the implementation methods described in the first to ninth aspects. The memory may be located within or outside the device. Furthermore, the processor may be one or more.

[0069] In a seventeenth aspect, embodiments of this application also provide a computer-readable storage medium storing instructions that, when executed on a communication device, cause any of the implementation methods of the first to ninth aspects to be performed.

[0070] In an eighteenth aspect, embodiments of this application also provide a computer program product, which includes a computer program or instructions that, when executed by a communication device, cause any of the implementation methods in the first to ninth aspects to be executed.

[0071] In a nineteenth aspect, embodiments of this application also provide a chip system, including: a processor for executing any of the implementation methods in the first to sixth aspects described above.

[0072] In a twentieth aspect, embodiments of this application also provide a communication system, including: a mobility management network element and an access network device. The mobility management network element is used to execute any implementation method of the first to third aspects. The access network device is used to send satellite coverage information of the cell where the terminal device is located to the mobility management network element.

[0073] In a twentieth aspect, embodiments of this application also provide a communication system, including: a mobility management network element and an access network device. The mobility management network element is used to execute any implementation method of the seventh aspect. The access network device is used to execute any implementation method of the ninth aspect. Attached Figure Description

[0074] Figure 1(a) is a schematic diagram of a 5G network architecture based on a service-oriented architecture; Figure 1(b) is a schematic diagram of a 5G network architecture based on a point-to-point interface; Figure 2A flowchart illustrating a communication method provided in an embodiment of this application; Figure 3(a) is a schematic diagram of the periodic TAU cycle provided in the embodiment of this application; Figure 3(b) is a schematic diagram of the eDRX cycle provided in the embodiment of this application; Figure 3(c) is a schematic diagram of the sleep time period provided in the embodiment of this application; Figure 4 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 5 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 6 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 7 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 8 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 9 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 10 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 11 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 12 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 13(a) is a schematic diagram of a periodic TAU cycle or a periodic registration cycle provided in the embodiments of this application; Figure 13(b) is another schematic diagram of the periodic TAU cycle or periodic registration cycle provided in the embodiments of this application; Figure 14 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 15 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 16(a) is a flowchart illustrating a communication method provided in an embodiment of this application; Figure 16(b) is a flowchart illustrating a communication method provided in an embodiment of this application; Figure 17 A schematic diagram of a communication device provided in an embodiment of this application; Figure 18 This is a schematic diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0075] To address the challenges of wireless broadband technology and maintain the leading edge of the 3rd Generation Partnership Project (3GPP) network, the 3GPP standards group developed the next-generation mobile communication network system architecture, known as the 5th generation (5G) network architecture. This architecture not only supports radio access technologies defined by the 3GPP standards group (such as Long Term Evolution (LTE) and 5G Radio Access Network (RAN)) to access the 5G core network (CN), but also supports access to the core network using non-3GPP access technologies through non-3GPP interworking functions (N3IWF) or next-generation packet data gateways (ngPDG).

[0076] Figure 1(a) is a schematic diagram of a service-based 5G network architecture. The 5G network architecture shown in Figure 1(a) may include terminal devices, access network devices, and core network devices. Terminal devices access the data network (DN) through access network devices and core network devices. The core network equipment includes, but is not limited to, some or all of the following network elements: authentication server function (AUSF) network element (not shown in the figure), unified data management (UDM) network element, unified data repository (UDR) network element, network repository function (NRF) network element (not shown in the figure), network exposure function (NEF) network element (not shown in the figure), application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, binding support function (BSF) network element (not shown in the figure), and network data analysis function (NWDAF) network element (not shown in the figure).

[0077] Terminal devices can be user equipment (UE), mobile stations, mobile terminals, etc. They can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can include mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, urban air mobility vehicles (such as drones and helicopters), ships, robots, robotic arms, and smart home devices.

[0078] Access network equipment can be either Radio Access Network (RAN) equipment or Wired Access Network (FAN) equipment. RAN equipment includes 3GPP access network equipment, untrusted non-3GPP access network equipment, and trusted non-3GPP access network equipment. 3GPP access network equipment includes, but is not limited to: evolved NodeBs (eNodeBs) in LTE, next-generation NodeBs (gNBs) in 5G mobile communication systems, base stations in future mobile communication systems, or modules or units that perform some base station functions, such as central units (CUs) and distributed units (DUs). Untrusted non-3GPP access network equipment includes, but is not limited to: untrusted non-3GPP access gateways or N3IWF devices, untrusted wireless local area network (WLAN) access points (APs), switches, and routers. Trusted non-3GPP access network equipment includes, but is not limited to: trusted non-3GPP access gateways, trusted WLAN APs, switches, and routers. Wired access network equipment includes, but is not limited to: wireline access gateway, fixed telephone network equipment, switches, and routers.

[0079] Access network equipment and terminal equipment can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites.

[0080] The AMF (Automatic Mobility Management) network element includes functions such as mobility management and access authentication / authorization. In addition, it is responsible for transmitting user policies between terminal devices and the PCF (Programmable Default Function) network element.

[0081] The SMF network element includes functions such as performing session management, executing control policies issued by the PCF network element, selecting the UPF network element, and allocating Internet Protocol (IP) addresses to terminal devices.

[0082] UPF network elements include functions such as user plane data forwarding, session / flow-based billing and statistics, and bandwidth limiting.

[0083] UDM network elements include functions such as managing contracted data and authorizing user access.

[0084] UDR network elements include functions for storing and retrieving data of various types, such as contract data, policy data, and application data.

[0085] NEF network elements are used to support the opening of capabilities and events.

[0086] AF (Application Provider) network elements convey application-side requests to the network side, such as QoS requirements or user state event subscriptions. AF network elements can be third-party functional entities or application services deployed by operators, such as IP Multimedia Subsystem (IMS) voice call services.

[0087] PCF network elements include policy control functions responsible for billing at the session and service flow levels, QoS bandwidth guarantee and mobility management, and terminal policy decision-making. PCF network elements include access and mobility management policy control function (AM PCF) network elements and session management policy control function (SM PCF) network elements. AM PCF network elements can provide mobility management policies, while SM PCF network elements can provide session management policies.

[0088] NRF network elements can be used to provide network element discovery functionality, providing network element information corresponding to the network element type based on requests from other network elements. NRF network elements also provide network element management services, such as network element registration, updates, deregistration, and network element status subscription and push.

[0089] BSF network elements can provide functions such as BSF service registration / deregistration / update, connection detection with NRF network elements, session binding information creation, terminal device information acquisition, and session binding information query for duplicate IP addresses.

[0090] The AUSF network element is responsible for authenticating users to determine whether to allow users or devices to access the network.

[0091] The NWDAF network element is primarily used to collect data (including one or more of the following: terminal device data, access network device data, core network data, and third-party application data), and to provide data analysis services based on machine learning models. It can output data analysis results for use by the network, network management, and applications in policy decision-making. The NWDAF network element can be a standalone element or shared with other network elements, such as being integrated into a PCF or AMF network element.

[0092] A Domain Provider (DN) is a network located outside the carrier's network. A carrier's network can connect to multiple DNs, and various services can be deployed on a DN, providing data and / or voice services to terminals. For example, a DN might be the private network of a smart factory. Sensors installed in the workshop can act as terminals, and a control server for these sensors is deployed within the DN. The control server provides services to the sensors. Sensors can communicate with the control server, receive instructions from it, and transmit the collected sensor data back to the control server accordingly. Another example is a DN serving as an internal office network for a company. Employees' mobile phones or computers can act as terminals, accessing information and data resources on the company's internal office network.

[0093] In Figure 1(a), Npcf, Nufr, Nudm, Naf, Namf, and Nsmf are the service interfaces provided by PCF, UDR, UDM, AF, AMF, and SMF, respectively, used to call the corresponding service operations. N1, N2, N3, N4, and N6 are interface sequence numbers, and the meanings of these interface sequence numbers are as follows: 1) N1: The interface between the AMF and the terminal device, which can be used to transmit non-access stratum (NAS) signaling (such as QoS rules from the AMF) to the terminal device.

[0094] 2) N2: The interface between the AMF and the access network equipment, which can be used to transmit radio bearer control information from the core network side to the access network equipment.

[0095] 3) N3: The interface between the access network device and the UPF, mainly used to transmit uplink and downlink user plane data between the access network device and the UPF.

[0096] 4) N4: The interface between SMF and UPF, which can be used to transmit information between the control plane and the user plane, including the distribution of forwarding rules, QoS rules, traffic statistics rules, etc. from the control plane to the user plane, as well as the reporting of information from the user plane.

[0097] 5) N6: The interface between UPF and DN, used to transmit uplink and downlink user data streams between UPF and DN.

[0098] Figure 1(b) is a schematic diagram of a 5G network architecture based on point-to-point interfaces. The functions of the network elements can be referred to the corresponding functions of the network elements in Figure 1(a), and will not be repeated here. The main difference between Figure 1(b) and Figure 1(a) is that the interfaces between the control plane network elements in Figure 1(a) are service-oriented interfaces, while the interfaces between the control plane network elements in Figure 1(b) are point-to-point interfaces.

[0099] In the architecture shown in Figure 1(b), the interface names and functions between the various network elements are as follows: 1) The meanings of interfaces N1, N2, N3, N4 and N6 can be found in the previous description.

[0100] 2) N5: The interface between AF and PCF, which can be used for application service request issuance and network event reporting.

[0101] 3) N7: The interface between PCF and SMF, which can be used to issue protocol data unit (PDU) session granularity and business data stream granularity control strategies.

[0102] 4) N8: The interface between AMF and UDM, which can be used by AMF to obtain access and mobility management related subscription data and authentication data from UDM, as well as by AMF to register terminal device mobility management related information with UDM.

[0103] 5) N9: User plane interface between UPFs, used to transmit uplink and downlink user data streams between UPFs.

[0104] 6) N10: The interface between SMF and UDM, which can be used by SMF to obtain session management-related subscription data from UDM, and by SMF to register terminal device session-related information with UDM.

[0105] 7) N11: The interface between SMF and AMF, which can be used to transmit PDU session tunnel information between access network equipment and UPF, transmit control messages sent to terminal equipment, and transmit radio resource control information sent to access network equipment, etc.

[0106] 8) N15: The interface between PCF and AMF, which can be used to issue terminal policies and access control related policies.

[0107] 9) N35: The interface between UDM and UDR, which can be used by UDM to obtain user subscription data information from UDR.

[0108] 10) N36: The interface between PCF and UDR, which can be used by PCF to obtain policy-related contract data and application data related information from UDR.

[0109] It is understood that the aforementioned network element or function can be a network component in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the aforementioned network element or function can be implemented by one device, multiple devices working together, or a functional module within a single device; this application embodiment does not specifically limit this.

[0110] In this application embodiment, the mobility management network element can be a mobility management entity (MME) in a fourth-generation (4G) network, an AMF network element in a 5G network, or other network elements with the functions of an MME or AMF network element in a future communication system.

[0111] In this application embodiment, the access network device can be an access network device in a 4G network (such as an eNB), an access network device in a 5G network (such as a gNB), or other network elements in a future communication system that have the functions of an access network device in a 4G network or an access network device in a 5G network.

[0112] In this embodiment of the application, the policy control network element can be a policy and charging rules function (PCRF) network element in a 4G network, a PCF network element in a 5G network, or other network elements in a future communication system that have the functions of a PCRF network element or a PCF network element.

[0113] In this embodiment of the application, the storage network element can be the home subscriber server (HSS) in a 4G network, the UDR network element in a 5G network, or other network elements with the functions of HSS or UDR network elements in future communication systems.

[0114] In this embodiment of the application, periodic tracking area update (TAU) and periodic registration have the same meaning. Periodic TAU is the term used in 4G, and periodic registration is the term used in 5G.

[0115] In this embodiment, the periodic TAU period can be represented by a periodic TAU timer, and the periodic registration period can be represented by a periodic registration timer. Here, the periodic TAU timer is the term used in 4G, and the periodic registration timer is the term used in 5G.

[0116] In this embodiment of the application, the terms "de-attachment process" and "de-registration process" have the same meaning. "De-attachment process" is the term used in 4G, while "de-registration process" is the term used in 5G.

[0117] In this embodiment of the application, the maximum waiting time can be the downlink buffer duration in a 4G network, the maximum waiting time in a 5G network, or other parameters in a future communication system that have a downlink buffer duration or a maximum waiting time.

[0118] mMTC is one of the important application scenarios for 5G networks, mainly targeting various Internet of Things (IoT) business applications based on cellular networks, such as maritime / land / railway / air transportation, oil and gas extraction and measurement, environmental monitoring, and mining development. To meet these needs, in the 4G era, 3GPP defined narrowband Internet of Things (NB-IoT) and enhanced machine-type communication (eMTC) (also known as Long Term Evolution Machine Type Communication (LTE-M)).

[0119] However, to ensure wider network coverage and achieve seamless global coverage, low-Earth orbit (LEO) satellites have emerged. LEO satellites can assist NB-IoT / eMTC in achieving global IoT coverage, thereby avoiding network coverage problems caused by insufficient terrestrial network infrastructure deployment.

[0120] Taking 5G as an example, for terminal devices in NB-IoT / eMTC scenarios, when they enter an idle state, they may enter a sleep state. At this time, the terminal device and the AMF on the core network side will maintain a coarse synchronization to ensure that the AMF can sense when the terminal device enters a sleep state. When downlink data from a terminal device arrives, the UPF will notify the SMF, and then the SMF will notify the AMF. If the AMF finds that the terminal device is still in a sleep state and unreachable, it will estimate a maximum waiting time based on the sleep time of the terminal device and return this maximum waiting time to the SMF to instruct the SMF to wait for the maximum waiting time before performing downlink paging. The SMF will also determine the maximum buffer time based on the maximum waiting time and buffer the downlink data of the terminal device according to the maximum buffer time, waiting for the terminal device to become available.

[0121] There are two main energy-saving methods for terminal devices: Power Saving Model (PSM) and Extended Discontinuous Reception (eDRX). PSM refers to a terminal device entering a sleep state after a period of time in an idle state, until there is uplink traffic or periodic registration / periodic TAU. eDRX refers to a terminal device entering a sleep state at fixed times when there is no traffic transmission, and waking up at a specified time to listen for paging information from the network side. At this time, the terminal device is reachable and can receive paging messages from the network side. Unless otherwise specified, the eDRX discussed in this article refers to idle-state eDRX.

[0122] 3GPP has introduced NB-IoT and eMTC into its satellite network architecture, enabling satellites to support 4G NB-IoT and eMTC. Meanwhile, 5G satellite architecture has been under research since Release 16 (5G), aiming to achieve the integration of 5G architecture with satellites.

[0123] Unlike terrestrial coverage, satellite coverage is constantly in motion because satellites need to orbit the Earth regularly. The R17 5G satellite architecture study continues to use the concept of fixed cells from terrestrial coverage. This means that although the cells covered by satellites are moving, the ground access network equipment maps the satellite-covered cells to fixed terrestrial cells based on the correspondence between satellite coverage and fixed terrestrial cells. This ensures that the core network side perceives the cell where the terminal device is located as a fixed terrestrial cell.

[0124] Furthermore, during the initial deployment of satellites or for cost considerations, there may be scenarios where coverage is discontinuous for a specific ground area. For example, at an oil field deep in the desert, while one or more satellites are orbiting the Earth regularly, they may only provide network communication services to the oil field during specific time periods, such as for data collection and reporting from various sensors. In other words, the network communication service provided by satellites to ground-based terminal devices is discontinuous; the terminal devices will be covered by the satellite network during some periods and will not be covered during others.

[0125] The existence of non-contiguous coverage will lead to the following problems: Question 1: Terminal devices may remain uncovered by satellite networks for extended periods. Traditional NB-IoT or eMTC eDRX sleep cycles are too short for this scenario. In other words, following the traditional sleep cycle pattern of NB-IoT or eMTC eDRX, the terminal device may still be out of satellite network coverage after waking up from its sleep cycle.

[0126] Question 2: When downlink data arrives on the network side, the core network cannot determine whether the terminal device is reachable, making it difficult to ensure successful paging.

[0127] In the embodiments of this application, the satellite coverage information of the terminal device indicates the time periods during which the terminal device is covered by the satellite network and / or the time periods during which it is not covered by the satellite network. For example, the satellite coverage information of the terminal device indicates that the terminal device is not covered by the satellite network from 8:00 AM to 9:00 AM every day, and / or indicates that the terminal device is covered by the satellite network from 0:00 AM to 8:00 AM and from 9:00 AM to 0:00 AM every day. The satellite coverage information of the terminal device can be the satellite coverage information corresponding to the location of the terminal device, or the satellite coverage information of the satellite cell where the terminal device is located, or the satellite coverage information corresponding to the tracking area (TA) where the terminal device is located. For example, if the terminal device is located in cell 1, then the satellite coverage information of the terminal device can be the satellite coverage information of cell 1. As another example, if the terminal device is located in cell 2, then the satellite coverage information of the terminal device can be the satellite coverage information of cell 2. Alternatively, the satellite coverage information of the terminal device in the embodiments of this application can also be ephemeris information.

[0128] In the embodiments of this application, the ephemeris information of a cell refers to the regularity of the satellite's orbit around the Earth corresponding to that cell. For example, ephemeris information includes satellite orbital plane parameters, satellite parameters such as satellite speed, satellite direction of movement, satellite orbital distance from the ground, reference time points, etc. Based on the ephemeris information of one or more satellites corresponding to a satellite cell, the time period during which the cell is covered by the satellite network and / or the time period during which it is not covered by the satellite network can be determined. The satellite coverage information of a cell indicates the time period during which the cell is covered by the satellite network and / or the time period during which it is not covered by the satellite network. For example, if there are three satellite cells under the access network device, namely satellite cell 1, satellite cell 2, and satellite cell 3, then the N2 establishment message includes the identification information of satellite cell 1, the ephemeris information 1 or satellite coverage information 1 corresponding to satellite cell 1, the identification information of satellite cell 2, the ephemeris information 2 or satellite coverage information 2 corresponding to satellite cell 2, the identification information of satellite cell 3, and the ephemeris information 3 or satellite coverage information 3 corresponding to satellite cell 3.

[0129] refer to Figure 2 This is a flowchart illustrating a communication method provided in an embodiment of this application. This method can be used to solve the aforementioned problem 1. The method includes the following steps: Step 201: The mobility management network element determines the sleep time information of the terminal device based on the satellite coverage information of the terminal device.

[0130] As one implementation method, after the access network device powers on, it needs to establish a connection with the mobility management network element (MLE). Taking a 5G network as an example, this interface is the N2 interface. Therefore, the access network device sends an N2 establishment message to the MLE. This N2 establishment message can carry the identification information of the satellite cells under the access network device, as well as the ephemeris information or satellite coverage information of the satellites corresponding to each satellite cell. Subsequently, when the terminal device registers with the network, the MLE can obtain the satellite cell information where the terminal device is located. For example, if the terminal device is located in satellite cell 1 under the access network device, the MLE determines that the satellite coverage information of cell 1 is the satellite coverage information of the terminal device. If the MLE receives the ephemeris information of the satellite corresponding to cell 1 from the access network device, the MLE also needs to determine the satellite coverage information of cell 1 based on the ephemeris information of the satellite corresponding to cell 1. Optionally, the MLE can also save this satellite coverage information as the satellite coverage information of the terminal device accessing the network from cell 1.

[0131] As another implementation method, during the terminal device's registration with the network, the access network device can send the ephemeris information or satellite coverage information of the satellite corresponding to the satellite cell where the terminal device is located to the mobility management network element. For example, the terminal device sends a registration request message to the access network device. After receiving the registration request message, the access network device, while sending the registration request message to the mobility management network element, also sends the ephemeris information or satellite coverage information of the satellite corresponding to the satellite cell where the terminal device is located, that is, adds the ephemeris information or satellite coverage information of the satellite corresponding to the satellite cell where the terminal device is located to the initial N2 message. If the access network device sends the ephemeris information of the satellite corresponding to the satellite cell where the terminal device is located, the mobility management network element needs to determine the satellite coverage information of the satellite cell where the terminal device is located based on the ephemeris information. Then, the mobility management network element uses the satellite coverage information of that cell as the satellite coverage information of the terminal device.

[0132] As another implementation method, a third-party network element, such as an application server outside the core network or a network element within the core network dedicated to satellite interaction or satellite management, can send the ephemeris information or satellite coverage information of the satellite cell where the terminal device is located to the mobility management network element. If the third-party network element sends the ephemeris information of the satellite cell where the terminal device is located, the mobility management network element needs to determine the satellite coverage information of the satellite cell where the terminal device is located based on the ephemeris information. Then, the mobility management network element uses the satellite coverage information of that cell as the satellite coverage information of the terminal device.

[0133] The sleep time information includes the sleep period when the terminal device is not covered by the satellite network.

[0134] As one implementation method, the mobility management network element also determines one or more of the eDRX cycle, periodic TAU cycle, or periodic registration cycle of the terminal device based on satellite coverage information. The sleep time period corresponding to the sleep time information is included within the sleep time range of the eDRX cycle, periodic TAU cycle, or periodic registration cycle. In this implementation method, the sleep time information here includes the sleep start time, which is located within the eDRX cycle, periodic TAU cycle, or periodic registration cycle. Referring to Figure 3(a), it is a schematic diagram of a periodic TAU cycle. At the beginning of a periodic TAU cycle, the terminal device executes the periodic TAU procedure to initiate a network connection. Subsequently, the terminal device enters a sleep state from the sleep start time, and the sleep time period of the terminal device within the periodic TAU cycle includes the time period when the terminal device is not covered by the satellite network. This ensures that the terminal device enters a sleep state during the time period when it is not covered by the satellite network, avoiding the terminal device performing the periodic TAU procedure during the time period without network coverage, and reducing the power consumption of the terminal device. The sleep duration is greater than or equal to the duration when the terminal device is not covered by the satellite network. Referring to Figure 3(a), time T1 is the sleep start time, and time T2 is the sleep end time. T2 is also the end time of this TAU cycle. The difference between T2 and T1 equals the duration during which the terminal device is not covered by the satellite network. The sleep time information determined in step 201 is the sleep start time in the example of Figure 3(a). In 4G networks, this process is generally called a periodic TAU process, while in 5G networks it is called a periodic registration process. Referring to Figure 3(b), a schematic diagram of a certain eDRX cycle is shown. Within a paging time window after the start of an eDRX cycle, the terminal device performs listening according to the DRX cycle. If there is no network connection requirement after the paging time window arrives, it will enter sleep mode at the sleep start time. The sleep time period of the terminal device within this eDRX cycle includes the period during which the terminal device is not covered by the satellite network, thus ensuring that the terminal device enters sleep mode during the period without satellite network coverage. This avoids the terminal device waking up to listen for paging messages during periods without satellite network coverage, reducing the terminal device's power consumption. The sleep duration is greater than or equal to the duration during which the terminal device is not covered by the satellite network. Referring to Figure 3(b), time T1 is the sleep start time, and time T2 is the sleep end time. T2 is also the end time of this eDRX cycle. The difference between T2 and T1 is equal to or greater than the duration during which the terminal device is not covered by the satellite network. The sleep time information determined in step 201 includes the sleep start time in the example of Figure 3(b).

[0135] As another implementation method, the sleep time information includes a sleep start time and a sleep end time, and the sleep period between the sleep start time and the sleep end time includes the time period during which the terminal device is not covered by the satellite network. Alternatively, the sleep time information includes a sleep start time and a sleep duration, and the sleep end time can be obtained from the sleep start time and sleep duration. During the sleep period corresponding to the sleep time information, the terminal device will continuously sleep and will not perform any services, including not executing periodic TAU or periodic registration processes. In this method, the time period during which the terminal device is not covered by the satellite network, indicated by the satellite coverage information, is not included in any eDRX cycle or TAU cycle, but is a separate sleep period. Refer to Figure 3(c), which is a schematic diagram of the sleep period. The sleep time information indicates a separate sleep period, which coincides with or is longer than the time period during which the terminal device is not covered by the satellite network. During this sleep period, the terminal device enters a sleep state, ensuring that it enters a sleep state during the time period during which it is not covered by the satellite network, avoiding unnecessary and ineffective network connections, and reducing the terminal device's power consumption. Referring to Figure 3(c), time T1 is the sleep start time, and time T2 is the sleep end time. The time period from T1 to T2 coincides with or exceeds the time period during which the terminal device is not covered by the satellite network. Optionally, after this sleep period, an eDRX cycle begins. This eDRX cycle can be determined according to existing schemes, and it also includes a sleep period, which can be called a regular eDRX sleep period. The sleep time information determined in step 201 includes the sleep start time and sleep end time in the example of Figure 3(c). Alternatively, the sleep time information determined in step 201 includes the sleep start time and sleep duration in the example of Figure 3(c).

[0136] Step 202: The mobility management network element sends sleep time information to the terminal device. Correspondingly, the terminal device receives this sleep time information.

[0137] As one implementation method, the mobility management network element can carry the sleep time information in the registration acceptance message sent to the terminal device. Optionally, the registration acceptance message may also include one or more of the eDRX period, the periodic registration period, or the periodic TAU period. Taking a 4G network as an example, the sleep time information can be carried in the attach acceptance message or the TAU acceptance message sent to the terminal device.

[0138] Step 203: The terminal device goes into sleep mode based on the sleep time information.

[0139] Specifically, the terminal device enters a sleep state within the sleep time period corresponding to the sleep time information. This sleep time period includes the time period during which the terminal device is not covered by the satellite network.

[0140] Step 204: When the deregistration timer (or deattachment timer) corresponding to the terminal device times out, the mobility management network element determines that the terminal device is not covered by the satellite network based on the satellite coverage information, and determines not to perform deregistration (or deattachment) on the terminal device.

[0141] Step 204 is an optional step.

[0142] Not performing deregistration on the terminal device can also be understood as keeping the terminal device's registration status unchanged. Similarly, not performing detachment on the terminal device can be understood as keeping the terminal device's attachment status unchanged.

[0143] In 4G networks, when the detach timer (or implicit detach timer) for a terminal device times out, if the Mobility Management Element (MME) determines, based on satellite coverage information, that the terminal device is not covered by the satellite network, it will not perform detachment, maintaining the terminal device's current mobility management state as attached or EMM-registered. Conversely, if the MME determines, based on satellite coverage information, that the terminal device is covered by the satellite network, it will perform detachment, changing the terminal device's current mobility management state to detach or EMM-deregistered. This scheme reduces the number of times the terminal device's state switches between attached and detached, or between registered and unregistered, thus reducing signaling interaction between the terminal device and the network and lowering the terminal device's power consumption. This is because when a terminal device is not covered by a satellite network, its power consumption is relatively low. If the mobility management network element removes the terminal device, the terminal device will have to reattach after it is covered by a satellite network, resulting in more signaling interactions and increased power consumption.

[0144] In 5G networks, when the deregistration timer (or implicit deattachment timer) for a terminal device times out, if the Mobility Management Element (AMF) determines, based on satellite coverage information, that the terminal device is not covered by the satellite network, it will not perform deregistration. Conversely, if the AMF determines, based on satellite coverage information, that the terminal device is covered by the satellite network, it will not perform registration, thus maintaining the terminal device in a registered state. According to this scheme, when a terminal device is not covered by the satellite network, the AMF does not deregister it, reducing the number of times the terminal device switches between registered and deregister states, thereby reducing signaling interactions between the terminal device and the network and lowering the terminal device's power consumption. This is because when a terminal device is not covered by the satellite network, its power consumption is relatively low. If the AMF were to deregister the terminal device, it would have to re-register after being covered by the satellite network, resulting in more signaling interactions and increased power consumption.

[0145] In the above scheme, the mobility management network element determines the sleep time information based on the satellite coverage information of the terminal device. The sleep time period corresponding to this sleep time information includes the time period when the terminal device is not covered by the satellite network, thereby ensuring that the terminal device can sleep as much as possible during the time period when it is not covered by the satellite network, avoiding unnecessary network connection operations such as cell scanning and cell selection, so as to save the power consumption of the terminal device.

[0146] refer to Figure 4 This is a flowchart illustrating a communication method provided in an embodiment of this application. This method can be used to solve the aforementioned problem 1. The method includes the following steps: Step 401: When the deregistration timer (or deattachment timer) corresponding to the terminal device times out, the mobility management network element determines that the terminal device is not covered by the satellite network based on the satellite coverage information of the terminal device.

[0147] The method for determining the satellite coverage information of the terminal device by the mobility management network element can be referred to the description of step 201 above, and will not be repeated here.

[0148] The deregistration timer can also be an implicit deregistration timer; this is not a limitation in this paper. Similarly, the detach timer can also be an implicit detach timer; this is not a limitation in this paper.

[0149] Step 402: The mobility management network element determines that it will not perform deregistration (or deattachment) on the terminal device.

[0150] Not performing deregistration on the terminal device can be understood as keeping the terminal device's registration status unchanged. Similarly, not performing detachment on the terminal device can be understood as keeping the terminal device's attachment status unchanged, i.e., keeping the terminal device in EMM registration status. Optionally, not performing deregistration on the terminal device may occur in response to the terminal device not being covered by the satellite network.

[0151] In 4G networks, when the detach timer for a terminal device times out, if the Mobility Management Element (MME) determines, based on satellite coverage information, that the terminal device is not covered by the satellite network, it will not perform detachment, maintaining the terminal device's current Mobility Management state as attached or EMM-registered. Conversely, if the MME determines, based on satellite coverage information, that the terminal device is covered by the satellite network, it will perform detachment, changing the terminal device's current Mobility Management state to detach or EMM-deregistered. This scheme reduces the number of times the terminal device switches between attached and detach states when it is not covered by the satellite network, thus reducing signaling interactions between the terminal device and the network and lowering the terminal device's energy consumption. This is because when the terminal device is not covered by the satellite network, its energy consumption is relatively low. If the MME detaches the terminal device, it will have to reattach after being covered by the satellite network, resulting in more signaling interactions and increased energy consumption.

[0152] In 5G networks, when the deregistration timer for a terminal device times out, if the Mobility Management Element (AMF) determines, based on satellite coverage information, that the terminal device is not covered by the satellite network, it will not perform deregistration. Conversely, if the AMF determines, based on satellite coverage information, that the terminal device is covered by the satellite network, it will not perform registration, thus maintaining the terminal device in a registered state. According to this scheme, when a terminal device is not covered by the satellite network, the AMF does not deregister it, reducing the number of times the terminal device switches between registration and deregistration, thereby reducing signaling interactions between the terminal device and the network and lowering the terminal device's power consumption. This is because when a terminal device is not covered by the satellite network, its power consumption is relatively low. If the AMF were to register the terminal device, it would have to re-register once it is covered by the satellite network, resulting in more signaling interactions and increased power consumption.

[0153] According to the above scheme, by reducing the switching between registration and deregistration, or between attachment and detachment of the terminal device, the signaling interaction between the terminal device and the network can be reduced, thereby reducing the energy consumption of the terminal device.

[0154] As one implementation method, after step 402 above, steps 403 and 404 can also be performed.

[0155] Step 403: The mobility management network element sends first information to the terminal device. Correspondingly, the terminal device receives the first information.

[0156] The first information indicates that when the terminal device has an uplink transmission requirement, it should perform uplink transmission based on the satellite network coverage.

[0157] Step 404: When there is an uplink transmission requirement, the terminal device determines that it is not covered by the satellite network based on the first information, and then determines not to perform uplink transmission.

[0158] The uplink transmission requirements here include, but are not limited to: periodic TAU, periodic registration, and uplink data transmission.

[0159] As one implementation method, the first information is the satellite coverage information of the terminal device described in step 401 above. The mobility management network element sends the satellite coverage information of the terminal device to the terminal device to instruct the terminal device to perform uplink transmission according to the satellite coverage information when it has uplink transmission needs. Therefore, when the terminal device has uplink transmission needs, it determines whether the terminal device currently has satellite network coverage based on the satellite coverage information. If it is not covered by a satellite network, it is determined that uplink transmission will not be performed. If it is covered by a satellite network, it is determined that uplink transmission will be performed.

[0160] As another implementation method, the first information is an indication message, specifically instructing the terminal device to automatically check satellite network coverage when it has uplink transmission needs, and to perform uplink transmission based on the satellite network coverage status. Therefore, when the terminal device has uplink transmission needs, it first checks whether it is currently covered by a satellite network. If it is not covered by a satellite network, it determines not to perform uplink transmission. If it is covered by a satellite network, it determines to perform uplink transmission.

[0161] As another implementation method, in step 403 above, while the mobility management network element sends the first information to the terminal device, it also sends the terminal device's satellite coverage information. In this case, the first information is an indication, specifically instructing the terminal device to perform uplink transmission based on the satellite coverage information when it has uplink transmission needs. Therefore, when the terminal device has uplink transmission needs, it determines whether it is covered by the satellite network based on the satellite coverage information. If it is not covered by the satellite network, it determines not to perform uplink transmission. If it is covered by the satellite network, it determines to perform uplink transmission.

[0162] According to the schemes in steps 403 and 404 above, when the terminal device is not covered by the satellite network, even if there is an uplink transmission requirement, uplink transmission will not be performed. This can avoid unnecessary and invalid network connection operations such as cell scanning and cell selection, thereby saving the energy consumption of the terminal device.

[0163] refer to Figure 5 This is a flowchart illustrating a communication method provided in an embodiment of this application. This method can be used to solve problem 2 mentioned above. The method includes the following steps: Step 501: The mobility management network element determines the satellite coverage information of the terminal device.

[0164] As one implementation method, the mobility management network element can determine the satellite coverage information of the terminal device according to the method described in step 201 above.

[0165] As another implementation method, the mobility management network element can also determine the satellite coverage information of the terminal device through the following method: The mobility management network element sends a paging message to the access network device. This paging message includes the identification information of the idle terminal device and indicates that the terminal device is being paged. Then, the access network device pagees the terminal device. If the access network device determines that the cell where the terminal device is located is not currently covered by the satellite network, the access network device will fail to page the terminal device. Therefore, the access network device sends a first message to the mobility management network element. This first message includes a paging failure indication and the satellite coverage information of the satellite cell where the terminal device is located. The paging failure indication is used to indicate that the reason for the paging failure is that the terminal device is not covered by the satellite network. Optionally, the paging failure indication also indicates that the mobility management network element needs to perform a reachability determination / paging based on the satellite coverage information. The satellite coverage information of the satellite cell where the terminal device is located is the satellite coverage information of the terminal device.

[0166] As another implementation method, the mobility management network element can also determine the satellite coverage information of the terminal device through the following method: The mobility management network element sends a paging message to the access network device. The paging message includes the identification information of the idle terminal device and indicates that the terminal device is being paged. Then, the access network device pagees the terminal device. If the access network device determines that the cell where the terminal device is located is not currently covered by the satellite network, the access network device will fail to page the terminal device. Therefore, the access network device sends a first message to the mobility management network element. The first message includes the satellite coverage information of the satellite cell where the terminal device is located. The satellite coverage information of the satellite cell where the terminal device is located is the satellite coverage information of the terminal device. The satellite coverage information is used to indicate that the reason for the paging failure is that the terminal device is not covered by the satellite network. Optionally, the satellite coverage information also indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0167] As one implementation method, when the mobility management network element is a 5G AMF network element, the AMF network element can execute step 501 after receiving the downlink data arrival notification from the SMF network element. That is, the downlink data arrival notification triggers the mobility management network element to execute step 501.

[0168] As one implementation method, when the mobility management network element is a 4G MME, the MME can execute step 501 after determining that there is downlink data to be transmitted on the user plane.

[0169] Step 502: The mobility management network element determines the maximum waiting time based on satellite coverage information. The maximum waiting time indicates the maximum duration that the waiting terminal device can reach.

[0170] The maximum waiting time here needs to cover the period during which the terminal device is not covered by the satellite network; or, in other words, the terminal device should be covered by the satellite network after the maximum waiting time has elapsed. This maximum waiting time can be the downlink buffer duration in 4G or the maximum waiting time in 5G.

[0171] Optionally, before step 502, the mobility management network element may also determine that the terminal device is unreachable based on satellite coverage information.

[0172] In 4G networks, the mobility management element is the MME. After determining the maximum waiting time, the MME can determine the downlink data buffer timeout based on this maximum waiting time. This timeout is used to indicate whether the core network side currently has data cached for the terminal device. After the downlink data buffer timeout expires, the MME will determine that there is no longer any downlink buffered data for the terminal device. In 4G networks, the maximum waiting time can also be referred to as the downlink data buffer time.

[0173] In 5G networks, this mobility management element is the AMF element. After determining the maximum waiting time, the AMF element can send the maximum waiting time to the SMF element. The SMF element can then determine the extended buffer time based on the maximum waiting time. This extended buffer time indicates the specific duration for which the user plane element buffers downlink data. If the extended buffer time expires and the buffered data has not yet been sent to the terminal device, the SMF will discard the corresponding buffered data. In 5G networks, the maximum waiting time can also be referred to as the estimated maximum waiting time.

[0174] According to the above scheme, the mobility management network element can determine the reachability based on the satellite coverage information of the terminal device. If the terminal device is unreachable, the maximum waiting time is determined based on the satellite coverage information to ensure that the terminal device is not paged or sent downlink data when it is not covered by the satellite network. This can reduce the energy consumption of the mobility management network element and reduce data loss.

[0175] As one implementation method, before step 201, before step 401, and / or before step 501, the mobility management network element further determines that the location of the terminal device is fixed or its movement trajectory is fixed. Alternatively, this can be understood as the mobility management network element determining that the terminal device is a fixed-location terminal device or a terminal device with a fixed movement trajectory. For example, the mobility management network element can obtain the subscription information of the terminal device and determine whether the location of the terminal device is fixed or its movement trajectory is fixed based on this subscription information. That is, the mobility management network element only performs the above-mentioned procedures for terminal devices with fixed locations or fixed movement trajectories. Figure 2 , Figure 4 and / or Figure 5 The corresponding implementation scheme. Here, "fixed movement trajectory" can be understood as the terminal device having a certain degree of mobility, but its movement trajectory is predictable, and the network side can perceive the geographical location of the terminal device.

[0176] The above solutions are illustrated below with specific examples. These solutions are applicable to 4G networks, 5G networks, or future communication networks such as 6G networks.

[0177] refer to Figure 6 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 2 One specific implementation of the corresponding embodiment.

[0178] The method includes the following steps: Step 601: The access network device sends an N2 setup message to the mobility management network element. Correspondingly, the mobility management network element receives the N2 setup message.

[0179] The N2 establishment message is sent after the access network equipment is powered on, during the process of establishing an N2 interface with the mobility management network element. If the current network is a 4G network, then this N2 interface corresponds to the S1-MME interface in the 4G network.

[0180] Optionally, the N2 establishment message includes the identification information of the satellite cells under the access network device and the ephemeris information or satellite coverage information of the satellites corresponding to each satellite cell.

[0181] Step 602: The terminal device sends a registration request message to the access network device. Correspondingly, the access network device receives the registration request message.

[0182] This registration request message is used to request registration with the network.

[0183] The registration request message can be a registration request message in a 5G network, or an attach message or TAU request message in a 4G network.

[0184] Step 603: The access network device sends the registration request message and access network (AN) parameters to the mobility management network element. Correspondingly, the mobility management network element receives the registration request message and the AN parameters. The registration request message is carried by the terminal device in the NAS message sent to the mobility management network element, and the AN parameters are added by the access network device in the initial N2 message and sent to the mobility management network element along with the registration request message.

[0185] If the N2 establishment message in step 601 above does not carry the identification information of the satellite cell under the access network device and the ephemeris information or satellite coverage information corresponding to each satellite cell, then in the subsequent registration process of the terminal device, the AN parameter added by the access network device may include the ephemeris information or satellite coverage information corresponding to the satellite cell where the terminal device is located.

[0186] Step 604: The mobility management network element determines whether the location of the terminal device is fixed or its movement trajectory is fixed.

[0187] Alternatively, it can be understood that the mobility management network element determines whether the terminal device is a fixed-location terminal device or a terminal device with a fixed movement trajectory.

[0188] As one implementation method, the mobility management network element can obtain the subscription information of the terminal device and determine whether the terminal device's location is fixed or its movement trajectory is fixed based on the subscription information.

[0189] Step 604 is an optional step.

[0190] Step 605: The mobility management network element determines the terminal device's hibernation start time, as well as one or more of the periodic TAU period, periodic registration period, or eDRX period, based on the ephemeris information or satellite coverage information corresponding to the satellite cell where the terminal device is located.

[0191] Specifically, if the mobility management network element receives ephemeris information corresponding to the satellite cell where the terminal device is located from the access network equipment, the mobility management network element determines the satellite coverage information corresponding to the satellite cell where the terminal device is located based on the ephemeris information.

[0192] In 5G networks, periodic TAU corresponds to a periodic registration process, while in 4G networks, it corresponds to a periodic TAU process.

[0193] The satellite coverage information corresponding to the satellite cell where the terminal device is located is the satellite coverage information of that terminal device.

[0194] As one implementation method, the time periods not covered by the satellite network as indicated by the satellite coverage information of the terminal device are included in a certain periodic registration period, or it can be understood that the dormant time periods within the periodic registration period include the time periods not covered by the satellite network as indicated by the satellite coverage information of the terminal device. A specific example of this implementation method can be found in Figure 3(a) above.

[0195] As one implementation method, the time period not covered by the satellite network as indicated by the satellite coverage information of the terminal device is included in a certain eDRX cycle, or it can be understood that the sleep time period within the eDRX cycle includes the time period not covered by the satellite network as indicated by the satellite coverage information of the terminal device. A specific example of this implementation method can be found in Figure 3(b) above.

[0196] Step 606, other steps in the registration process.

[0197] Step 607: The mobility management network element sends a non-access stratum (NAS) message to the terminal device. The terminal device then receives the NAS message.

[0198] The NAS message includes the hibernation start time, as well as one or more of the periodic TAU cycle, eDRX cycle, or periodic registration cycle.

[0199] As one implementation, the NAS message includes a registration accept message, an attach accept message, or a TAU accept message, which includes a hibernation start time, and also includes one or more of a periodic registration cycle, a periodic TAU cycle, or an eDRX cycle.

[0200] Step 608: The terminal device goes into hibernation during a periodic TAU cycle, a periodic registration cycle, or an eDRX cycle, depending on the hibernation start time.

[0201] As one implementation method, the terminal device enters a sleep state from the start time of a periodic TAU cycle and ends the sleep state at the end of the periodic TAU cycle. The sleep period of the terminal device includes the time period during which the terminal device is not covered by the satellite network. For example, the terminal device can enter sleep state according to the method shown in Figure 3(a).

[0202] As one implementation method, the terminal device enters a sleep state from the start time of the sleep period within the eDRX cycle and ends the sleep state at the end of the eDRX cycle. The sleep period of the terminal device includes the time period during which the terminal device is not covered by the satellite network. For example, the terminal device can enter sleep state according to the method shown in Figure 3(b).

[0203] In the above scheme, during the registration process of the terminal device, the mobility management network element determines the hibernation start time based on the ephemeris information or satellite coverage information corresponding to the cell provided by the access network device, and determines one or more of the eDRX period, periodic TAU period, or periodic registration period, thereby ensuring that the terminal device can hibernate as much as possible during the time period when it is not covered by the satellite network, avoiding unnecessary cell scanning, cell selection and other network connection operations, so as to save the power consumption of the terminal device.

[0204] refer to Figure 7 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 2 A specific implementation of the corresponding embodiment. The method includes the following steps: Steps 701 to 704 are the same as steps 601 to 604 above.

[0205] Step 704 is an optional step.

[0206] Step 705: The mobility management network element determines the sleep time information of the terminal device based on the ephemeris information or satellite coverage information corresponding to the satellite cell where the terminal device is located.

[0207] Specifically, if the mobility management network element receives ephemeris information corresponding to the satellite cell where the terminal device is located from the access network equipment, the mobility management network element determines the satellite coverage information corresponding to the satellite cell where the terminal device is located based on the ephemeris information. The satellite coverage information corresponding to the satellite cell where the terminal device is located is the satellite coverage information of the terminal device.

[0208] As one implementation method, the sleep time information includes sleep start time and sleep end time, and the sleep time period between the sleep start time and sleep end time is the time period during which the terminal device is not covered by the satellite network.

[0209] As one implementation method, the hibernation time information includes a hibernation start time and a hibernation end time, and the hibernation period between the hibernation start time and the hibernation end time includes the period during which the terminal device is not covered by the satellite network, that is, the hibernation period specified by the hibernation start time and the hibernation end time is greater than the period during which the terminal device is not covered by the satellite network.

[0210] As another implementation method, the hibernation time information includes hibernation start time and hibernation duration, wherein the hibernation end time can be obtained based on the hibernation start time and hibernation duration.

[0211] During the sleep period corresponding to this sleep time information, the terminal device will remain in sleep mode and will not perform any services, even if there is periodic TAU, periodic registration, or uplink data to be transmitted.

[0212] Optionally, the mobility management network element can determine one or more of the eDRX period, periodic TAU period, or periodic registration period based on service information during the time period when the terminal device is covered by the satellite network, according to existing methods.

[0213] As one implementation method, the time period indicated by the satellite coverage information of the terminal device that is not covered by the satellite network is not included in any eDRX cycle, periodic TAU cycle or periodic registration cycle, but is a separate dormant period.

[0214] Step 706, other steps in the registration process.

[0215] Step 707: The mobility management network element sends a NAS message to the terminal device. Correspondingly, the terminal device receives the NAS message.

[0216] The NAS message includes hibernation time information, and optionally, it may also include one or more of the following: eDRX cycle, periodic TAU cycle, or periodic registration cycle.

[0217] As one implementation method, the NAS message includes a registration accept message, an attach accept message, or a TAU accept message, which includes sleep time information. Optionally, the registration accept message may also include one or more of an eDRX cycle, a periodic TAU cycle, or a periodic registration cycle.

[0218] Step 708: The terminal device goes into sleep mode based on the sleep time information.

[0219] The system will hibernate during the hibernation period indicated by the hibernation time information and will not perform any business operations, even if there is periodic TAU, periodic registration, or uplink data to be transmitted.

[0220] Optionally, after the sleep time period indicated by the sleep time information, the terminal device enters the satellite network coverage area, and at this time it can go into sleep according to the eDRX cycle, periodic TAU cycle or periodic registration cycle.

[0221] Step 709: When the deregistration timer (or deattachment timer) corresponding to the terminal device times out, the mobility management network element determines whether to perform deregistration (or deattachment) on the terminal device based on the terminal device's sleep time information.

[0222] When the mobility management network element determines that the deregistration timer (or detach timer) for the terminal device has timed out, the mobility management network element determines, based on the terminal device's sleep time information, whether the terminal device is currently in a sleep period corresponding to a time when it is not covered by the satellite network. If the terminal device is currently in a sleep period corresponding to a time when it is not covered by the satellite network, the mobility management network element determines not to perform deregistration (or detach) for the terminal device. If the terminal device is not currently in a sleep period corresponding to a time when it is not covered by the satellite network, the mobility management network element determines to perform deregistration (or detach) for the terminal device.

[0223] Step 709 is an optional step.

[0224] In the above embodiment, during the registration process of the terminal device, the mobility management network element determines the sleep time information based on the ephemeris information or satellite coverage information corresponding to the satellite cell provided by the access network device. This ensures that the terminal device can sleep as much as possible during the time when it is not covered by the satellite network, avoiding unnecessary network connection operations such as cell selection, thereby saving the terminal device's energy consumption.

[0225] As one implementation method, the above Figure 7 The corresponding implementation can be applied to scenarios where the terminal device is not covered by the satellite network for extended periods. By introducing a new energy-saving mode, in which the terminal device remains in sleep mode during periods without satellite network coverage and does not perform any services, including periodic TAU, periodic registration, or uplink data transmission, unnecessary and ineffective network connection operations such as cell scanning and cell selection can be avoided, minimizing the energy consumption of the terminal device.

[0226] refer to Figure 8 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 4 One specific implementation of the corresponding embodiment.

[0227] The method includes the following steps: Steps 801 to 804 are the same as steps 601 to 604 above.

[0228] Step 804 is an optional step.

[0229] Step 805: The mobility management network element determines the satellite coverage information of the terminal device.

[0230] Specifically, if the mobility management network element receives ephemeris information corresponding to the satellite cell where the terminal device is located from the access network equipment, the mobility management network element determines the satellite coverage information corresponding to the satellite cell where the terminal device is located based on the ephemeris information. The satellite coverage information corresponding to the satellite cell where the terminal device is located is the satellite coverage information of the terminal device.

[0231] If the mobility management network element receives satellite coverage information corresponding to the satellite cell where the terminal device is located from the access network equipment, then the satellite coverage information corresponding to the satellite cell where the terminal device is located is the satellite coverage information of the terminal device.

[0232] Optionally, the mobility management network element can determine the eDRX period, periodic TAU period, or periodic registration period using existing methods.

[0233] Step 806, other steps in the registration process.

[0234] Step 807: The mobility management network element sends a NAS message to the terminal device. The terminal device then receives the NAS message.

[0235] The NAS message includes indication information and satellite coverage information of the terminal device. Optionally, the NAS message may also include one or more of eDRX cycles, periodic TAU cycles, or periodic registration cycles. The indication information is used to instruct the terminal device to initiate a periodic TAU or periodic registration process or transmit uplink data based on the terminal device's satellite coverage information when a periodic TAU or periodic registration timer expires, or when uplink data transmission occurs.

[0236] As one implementation method, the NAS message includes a registration acceptance message, an attachment acceptance message, or a TAU acceptance message, which includes indication information and satellite coverage information of the terminal device. Optionally, the message also includes one or more of eDRX cycles, periodic TAU cycles, or periodic registration cycles.

[0237] Step 808: The terminal device determines whether to initiate a periodic TAU, periodic registration, or transmit uplink data based on the instruction information and the satellite coverage information of the terminal device.

[0238] Specifically, based on the instruction information and the satellite coverage information of the terminal device, it is determined whether the terminal device is covered by the satellite network, that is, whether the terminal device is currently covered by the satellite network. When the terminal device is covered by the satellite network, it initiates periodic TAU, periodic registration, or transmits uplink data. When the terminal device is not covered by the satellite network, it does not initiate periodic TAU, periodic registration, or transmit uplink data.

[0239] Step 809: The mobility management network element determines whether to perform terminal device deregistration (or deattachment) based on the instruction information and the satellite coverage information of the terminal device.

[0240] Specifically, when the deregistration timer (or deattachment timer) for the terminal device times out, the system determines whether to perform deregistration (or deattachment) based on the satellite coverage information of the terminal device. If the terminal device is covered by a satellite network, the mobility management element performs deregistration (or deattachment) on the terminal device. If the terminal device is not covered by a satellite network, the mobility management element does not perform deregistration (or deattachment) on the terminal device.

[0241] In the above embodiments, during the registration, attachment, or TAU (Traffic Anchoring Unit) process of the terminal device, the mobility management network element determines the satellite coverage information of the terminal device and instructs the terminal device to perform periodic TAU, periodic registration, or uplink data transmission based on the satellite coverage information. This avoids the terminal device performing periodic TAU, periodic registration, or uplink data transmission during periods when it is not covered by the satellite network, thus avoiding unnecessary cell scanning, cell selection, and other network connection operations, thereby saving the terminal device's energy consumption. Furthermore, it also prevents the terminal device from being deregistered (or deattached) by the network side during periods when it is not covered by the satellite network.

[0242] As one implementation method, the above Figure 8 The corresponding implementation can be applied to scenarios where the terminal device is not covered by the satellite network for a long period of time. This is because the period of periodic TAU or periodic registration has a limit and cannot be very large. Therefore, when the terminal device is not covered by the satellite network for a long time, periodic TAU or periodic registration is inevitable. During this time, the terminal device is not covered by the satellite network, which will cause the terminal device to continuously perform cell scanning and cell selection, resulting in higher energy consumption. At the same time, the network side, not receiving periodic TAU or periodic registration from the terminal device, will deregister or deattach the terminal device. Therefore, in order to avoid unnecessary periodic TAU or periodic registration when the idle terminal device is not covered by the satellite network, the above-mentioned... Figure 8 In the corresponding embodiment, when the terminal device is not covered by the satellite network, the terminal device will not perform periodic TAU or periodic registration and uplink data transmission, and the mobility management network element on the network side will not perform deregistration (or deattachment) on the terminal device, thereby minimizing the signaling interaction between the terminal device and the mobility management network element and reducing the power consumption of the terminal device.

[0243] refer to Figure 9 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 4 One specific implementation of the corresponding embodiment.

[0244] The method includes the following steps: Steps 901 to 906 are the same as steps 801 to 806 above.

[0245] Step 907: The mobility management network element sends a NAS message to the terminal device. The terminal device then receives the NAS message.

[0246] The NAS message includes indication information. Optionally, the NAS message may also include one or more of the following: eDRX cycle, periodic TAU cycle, or periodic registration cycle. The indication information is used to instruct the terminal device to automatically detect whether it is covered by the satellite network when the periodic TAU timer expires, the periodic registration timer expires, or when there is uplink data transmission.

[0247] As one implementation, the NAS message includes a registration acceptance message, an attachment acceptance message, or a TAU acceptance message, which includes the indication information. Optionally, the registration acceptance message also includes an eDRX cycle and / or a TAU cycle.

[0248] Step 908: The terminal device determines whether to initiate a periodic TAU, periodic registration, or transmit uplink data based on the instruction information.

[0249] Specifically, based on the indication information, it is determined whether the terminal device is covered by the satellite network, that is, whether the terminal device is currently covered by the satellite network. If the terminal device is covered by the satellite network, it initiates periodic TAU, periodic registration, or transmits uplink data. If the terminal device is not covered by the satellite network, it does not initiate periodic TAU, periodic registration, or transmit uplink data.

[0250] Step 909 is the same as step 809 above.

[0251] The above embodiment describes a process where, during the registration of a terminal device, the mobility management network element instructs the terminal device to perform periodic TAU, periodic registration, or uplink data transmission based on whether it is covered by a satellite network. This avoids the terminal device performing periodic TAU, periodic registration, or uplink data transmission during periods when it is not covered by a satellite network, thus avoiding unnecessary cell scanning, cell selection, and other network connection operations, thereby saving the terminal device's energy consumption. Furthermore, it also prevents the terminal device from being deregistered (or deattached) by the network side during periods when it is not covered by a satellite network.

[0252] As one implementation method, the above Figure 9The corresponding implementation can be applied to scenarios where the terminal device is not covered by the satellite network for a long period of time. This is because the periodic TAU and periodic registration period has a limit and cannot be very large. Therefore, when the terminal device is not covered by the satellite network for a long time, it is inevitable to perform periodic TAU and periodic registration. At this time, the terminal device is not covered by the satellite network, which will cause the terminal device to continuously perform network connection operations such as cell scanning and cell selection, resulting in higher energy consumption. At the same time, the network side will deregister or deattach the terminal device because it does not receive periodic TAU or periodic registration requests from the terminal device. Therefore, in order to avoid unnecessary periodic TAU or periodic registration when the idle terminal device is not covered by the satellite network, the above-mentioned Figure 9 In the corresponding embodiment, when the terminal device is not covered by the satellite network, the terminal device will not perform periodic TAU or periodic registration and uplink data transmission, and the mobility management network element on the network side will not perform deregistration (or deattachment) on the terminal device, thereby minimizing the signaling interaction between the terminal device and the mobility management network element and reducing the power consumption of the terminal device.

[0253] refer to Figure 10 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 5 One specific implementation of the corresponding embodiment.

[0254] The method includes the following steps: Step 1001 is the same as step 601 above.

[0255] In step 1002, after the terminal device enters the idle state, the access network device sends an N2 message to the mobility management network element. Correspondingly, the mobility management network element receives the N2 message.

[0256] If the N2 establishment message in step 1001 above does not carry the identification information of the satellite cell under the access network device and the ephemeris information or satellite coverage information corresponding to each satellite cell, then the N2 message may include the ephemeris information or satellite coverage information corresponding to the satellite cell where the terminal device is located. Optionally, the N2 message may also include the identification information of the satellite cell where the terminal device is located. The satellite cell where the terminal device is located can also be understood as the last satellite cell accessed by the terminal device before entering the idle state. Specifically, the N2 message may be an N2 release message, which corresponds to the S1 release message in a 4G network.

[0257] Step 1003 is the same as step 604 above.

[0258] Step 1003 is an optional step.

[0259] Step 1004: The mobility management network element determines whether the terminal device is reachable.

[0260] As one implementation method, the mobility management network element determines whether a terminal device is reachable based on its satellite coverage information. If the terminal device is not currently covered by the satellite network, it is unreachable. If the terminal device is currently covered by the satellite network, its reachability is determined according to existing methods, such as the terminal device's power-saving sleep state. The satellite coverage information of the terminal device refers to the satellite coverage information of the satellite cell where the terminal device is located.

[0261] As one implementation method, the mobility management network element determines the reachability of a terminal device based on its satellite coverage information, as well as the eDRX period, periodic TAU period, or periodic registration period. If the terminal device is not currently covered by the satellite network, or is in the sleep period of the eDRX period, or is in the sleep period of the periodic TAU period, or is in the sleep period of the periodic registration period, then the terminal device is unreachable. If the terminal device is currently covered by the satellite network, and is not in the sleep period of the eDRX period, the periodic TAU period, or the periodic registration period, then the terminal device is reachable. It should be understood that the sleep period within the periodic TAU period or periodic registration period refers to the sleep period after the terminal device enters the idle state from the connected state, after a timer period, such as the PowerSaving Mode (PSM) in 4G networks or the Mobile Initiated Connection Only (MICO) mode in 5G networks.

[0262] Step 1005: If the terminal device is unreachable, the mobility management network element determines the maximum waiting time based on the satellite coverage information of the terminal device.

[0263] The specific implementation of this step can be found in the description of step 502 above.

[0264] Step 1006: When the terminal device enters a reachable state, the mobility management network element sends a paging message to the access network device. Correspondingly, the access network device receives the paging message.

[0265] The paging message includes the identification information of the terminal device and the identification information of the paging cell.

[0266] The paging cell can be the cell last accessed by the terminal device, or it can be any cell within the tracking area where the last accessed cell of the terminal device is located.

[0267] Step 1007: Access network equipment paging terminal equipment.

[0268] According to the above scheme, the mobility management network element can determine the reachability based on the satellite coverage information of the terminal device. If the terminal device is unreachable, the maximum waiting time is determined based on the satellite coverage information to ensure that the terminal device is not paged or sent downlink data when it is not covered by the satellite network. This can reduce the energy consumption of the mobility management network element and reduce data loss.

[0269] As one implementation method, if the mobility management network element in this scheme is the MME in 4G, then before step 1004, the MME can also receive a downlink data arrival notification from the user plane network element. This downlink data arrival notification triggers the MME to execute step 1004. Furthermore, after step 1005, the MME also determines the downlink data cache timeout duration based on the maximum waiting time or downlink cache time. This timeout duration is used to indicate whether the core network side currently caches data for the terminal device. After the downlink data cache timeout duration expires, the MME will determine that there is no longer any downlink cached data for the terminal device.

[0270] As one implementation method, if the mobility management network element in this scheme is an AMF network element in 5G, then before step 1004, the AMF network element can also receive a downlink data arrival notification from the SMF network element, which triggers the AMF network element to execute step 1004. Furthermore, after step 1005, the AMF network element instructs the SMF network element and / or the user plane network element to perform data caching based on the maximum waiting time. Then, the SMF network element can determine an extended caching time based on the maximum waiting time. This extended caching time indicates the specific duration for which the user plane network element caches downlink data. If the extended caching time expires and the cached data has not yet been sent to the terminal device, the SMF network element will discard the corresponding cached data.

[0271] refer to Figure 11 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 5 One specific implementation of the corresponding embodiment.

[0272] The method includes the following steps: Step 1101: The mobility management network element sends a paging message to the access network device. Correspondingly, the access network device receives the paging message.

[0273] The paging message includes the identification information of the terminal device and the identification information of the paging cell.

[0274] The paging cell can be the cell last accessed by the terminal device, or it can be any cell within the tracking area where the last accessed cell of the terminal device is located.

[0275] Step 1102: The access network equipment determines that the satellite cell where the terminal device is located is not covered by the satellite network.

[0276] As one implementation method, the access network device determines whether the terminal device has satellite network coverage based on the terminal device's satellite coverage information. If the terminal device is not currently covered by a satellite network, the paging attempt fails. If the terminal device is currently covered by a satellite network, a paging attempt is made to the terminal device. The satellite coverage information for the terminal device refers to the satellite coverage information of the satellite cell where the terminal device is located.

[0277] Step 1103: The access network device sends a first message to the mobility management network element. Correspondingly, the mobility management network element receives the first message.

[0278] Specifically, the first message can be an N2 message or a paging failure message.

[0279] Since the access network device determines that the terminal device is not currently covered by satellite, it sends a first message to the mobility management network element. The first message includes a paging failure indication and satellite coverage information of the terminal device. The paging failure indication is used to indicate that the reason for the paging failure is that the terminal device is not covered by the satellite network. Optionally, the paging failure indication also indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0280] As another implementation method, since the access network device determines that the terminal device is not currently covered by satellite, it sends a first message to the mobility management network element. The first message includes the satellite coverage information of the terminal device. The satellite coverage information indicates that the reason for the paging failure is that the terminal device is not covered by the satellite network. Optionally, the satellite coverage information also indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0281] Step 1104: The mobility management network element determines the maximum waiting time based on the satellite coverage information of the terminal device.

[0282] The specific implementation of this step can be found in the description of step 502 above.

[0283] Steps 1105 and 1106 are the same as steps 1006 and 1007 above.

[0284] According to the above scheme, when the mobility management network element notifies the access network equipment to page the terminal equipment, the access network equipment determines whether the terminal equipment can be paged based on the satellite coverage information of the terminal equipment. If the terminal equipment is not within the satellite network coverage area, the access network equipment notifies the mobility management network element that the paging has failed and sends the satellite coverage information of the terminal equipment to the mobility management network element. Thus, the mobility management network element determines the maximum waiting time based on the satellite coverage information, ensuring that the terminal equipment is not paged when it is not covered by the satellite network. This reduces unnecessary signaling interactions between the mobility management network element and the access network equipment, while avoiding the waste of paging resources by the access network equipment and the loss of downlink data by the terminal equipment.

[0285] As one implementation method, if the mobility management network element in this scheme is the MME in 4G, then before step 1101, the MME can also receive a downlink data arrival notification from the user plane network element. This downlink data arrival notification triggers the MME to execute step 1101. Furthermore, after step 1104, the MME also determines the downlink data cache timeout duration based on the maximum waiting time, i.e., the downlink cache time, to indicate whether the core network side currently caches data for the terminal device. After the downlink data cache timeout duration expires, the MME will determine that there is currently no downlink cached data for the terminal device.

[0286] As one implementation method, if the mobility management network element in this scheme is an AMF network element in 5G, then before step 1101, the AMF network element can also receive a downlink data arrival notification from the SMF network element. This downlink data arrival notification triggers the AMF network element to execute step 1101. Furthermore, after step 1104, the AMF network element instructs the SMF network element and / or the user plane network element to perform data caching based on the maximum waiting time. Then, the SMF network element can determine an extended caching time based on the maximum waiting time. This extended caching time indicates the specific duration for which the user plane network element caches downlink data. After the extended caching time expires and the cached data has not yet been sent to the terminal device, the SMF network element will discard the corresponding cached data.

[0287] the following Figure 12 Corresponding embodiments and Figure 14 In a corresponding embodiment, the example given is that the mobility management network element determines a suitable periodic TAU period or periodic registration period, so that the terminal device does not execute uplink signaling or uplink data transmission during periods not covered by the satellite network. In practical applications, the mobility management network element can also determine other parameters (such as service gap, eDRX) so that the terminal device does not execute uplink signaling or uplink data transmission during periods not covered by the satellite network. This can be understood as... Figure 12 Corresponding embodiments and Figure 14 In the corresponding embodiments, "periodic TAU period" and "periodic registration period" can be replaced with other parameters (such as service interval, eDRX). The definition of the service interval can be found in TS23.401 V17.2.0. These "other parameters" can be parameters representing duration.

[0288] refer to Figure 12 This is a flowchart illustrating a communication method provided in an embodiment of this application. For example, in a 4G application scenario, the mobility management network element and the access network device can be an MME and an eNB, respectively. In a 5G application scenario, the mobility management network element and the access network device can be an AMF and a gNB, respectively. In this embodiment, the terminal device is a satellite access type terminal device.

[0289] The method includes the following steps: Step 1201: The mobility management network element determines the periodic TAU period or periodic registration period based on the satellite coverage information of the terminal device.

[0290] Optionally, the location of the terminal device is fixed or its movement trajectory is fixed.

[0291] The meaning of satellite coverage information can be found in the aforementioned description, and will not be repeated here.

[0292] Optionally, if the mobility management network element determines that the terminal device is a satellite access type terminal device, the mobility management network element can determine the periodic TAU period or the periodic registration period based on the satellite coverage information of the terminal device.

[0293] In 4G, the Mobility Management Element (MME) determines the periodic Registration and Unlocking (TAU) period, which can be represented by a periodic TAU timer in specific implementations. In 5G, the Mobility Management Element (AMF) determines the periodic Registration and Unlocking (AU) period, which can also be represented by a periodic Registration and Unlocking (AU) timer in specific implementations.

[0294] The periodic TAU period includes the time period during which the terminal device is not covered by the satellite network, and the periodic registration period includes the time period during which the terminal device is not covered by the satellite network. This ensures that when the terminal device is not covered by the satellite network, it will not perform the periodic TAU process or the periodic registration process, and the terminal device will remain in a dormant state. That is, the time period from when the terminal device enters the idle state until the periodic TAU timer or the periodic registration timer expires includes the time period during which the terminal device is not covered by the satellite network.

[0295] The following describes different implementation methods for triggering the mobility management network element to execute the above step 1201.

[0296] Method 1: Based on the satellite coverage information of the terminal device, the mobility management network element determines that the terminal device will soon be without satellite network coverage. Then, it sends an indication message to the access network device, which instructs the access network device to execute the terminal device connection release procedure. The access network device then sends a UE context release request to the mobility management network element. This UE context release request is used to request the mobility management network element to release the context of the terminal device. After receiving the UE context release request, the mobility management network element triggers the execution of step 1201 above.

[0297] Method 2: The access network device determines that the terminal device will soon be without satellite network coverage based on the satellite coverage information of the terminal device, and then triggers the access network device to send a context release request to the mobility management network element. The context release request is used to request the mobility management network element to release the context of the terminal device. After receiving the UE context release request, the mobility management network element triggers the execution of the above step 1201.

[0298] Method 3: Based on the satellite coverage information of the terminal device, the terminal device determines that it will soon be without satellite network coverage, and then sends a TAU request or a mobile registration update request to the mobility management network element. After receiving the TAU request or mobile registration update request, the mobility management network element triggers the execution of step 1201 above.

[0299] Optionally, the mobility management network element also determines a first duration based on the satellite coverage information of the terminal device. This first duration refers to the time between the terminal device entering the idle state and entering the sleep state. This first duration can also be referred to as the active time of the terminal device. When the terminal device is in the active state, the network can paging the terminal device from the idle state to the connected state.

[0300] Step 1202: The mobility management network element sends a periodic TAU period or a periodic registration period to the terminal device.

[0301] In 4G, mobility management network elements, such as the MME, send periodic TAU cycles to the terminal device. Optionally, the MME sends a GUTI Reallocation Command to the terminal device, which carries the periodic TAU cycle. Alternatively, the MME sends a TAU Accept message to the terminal device, which also carries the periodic TAU cycle.

[0302] In 5G, mobility management elements, such as the AMF, send periodic registration cycles to terminal devices. Optionally, the AMF sends a UE Configuration Update Command to the terminal device, which carries the periodic registration cycle. Alternatively, the AMF sends a mobile registration update acceptance message to the terminal device, which also carries the periodic registration cycle.

[0303] As one implementation method, the mobility management network element sends periodic TAU periods or periodic registration periods to the terminal device through the access network device. That is, the mobility management network element sends periodic TAU periods or periodic registration periods to the access network device, and then the access network device sends periodic TAU periods or periodic registration periods to the terminal device.

[0304] Optionally, the mobility management network element can also send a first duration to the terminal device. This first duration refers to the time after the terminal device enters the idle state and before entering the sleep state. This first duration can also be referred to as the active time of the terminal device. When the terminal device is in the active state, the network can use paging to bring the terminal device from the idle state into the connected state.

[0305] Optionally, the mobility management network element can also send a cause value to the terminal device, which is a satellite discontinuous coverage, or the cause value is used to instruct the terminal device not to perform uplink transmission during sleep.

[0306] Step 1203: The terminal device performs a periodic TAU according to the periodic TAU cycle, or performs a periodic registration according to the periodic registration cycle.

[0307] Referring to Figure 13(a), this is a schematic diagram of a periodic TAU cycle or a periodic registration cycle provided in an embodiment of this application. The start time of the periodic TAU cycle (i.e., a periodic TAU timer) or the periodic registration cycle (i.e., a periodic registration timer) can be the moment when the terminal device enters an idle state. The time period corresponding to the periodic TAU cycle or the periodic registration cycle includes the time period during which the terminal device is not covered by the satellite network. During the time period when the terminal device is not covered by the satellite network, it enters a sleep state.

[0308] Referring to Figure 13(b), another schematic diagram of a periodic TAU cycle or periodic registration cycle provided in an embodiment of this application is shown. The start time of the periodic TAU cycle (i.e., a periodic TAU timer) or periodic registration cycle (i.e., a periodic registration timer) can be the moment the terminal device enters an idle state. The time period corresponding to the periodic TAU cycle or the periodic registration cycle includes the time period during which the terminal device is not covered by the satellite network. The time period corresponding to the periodic TAU cycle or the periodic registration cycle also includes a first duration during which the terminal device can be woken up by paging from the network side, thereby entering a connected state. During the time period during which the terminal device is not covered by the satellite network, it enters a sleep state.

[0309] Optionally, if the terminal device receives the above-mentioned cause value, and the cause value indicates that the terminal device will not perform uplink transmission during the sleep period, then when there is an uplink transmission requirement, the terminal device will not perform uplink transmission during the time period corresponding to the periodic TAU cycle or the periodic registration cycle, based on the cause value.

[0310] In the above scheme, the mobility management network element determines the periodic TAU period or periodic registration period based on the satellite coverage information of the terminal device. This ensures that the time period corresponding to the periodic TAU period or the periodic registration period includes the time period when the terminal device is not covered by the satellite network. This ensures that the terminal device can avoid performing the periodic TAU process or periodic registration process as much as possible during the time period when it is not covered by the satellite network, thereby avoiding unnecessary network connection operations such as cell selection and saving the terminal device's energy consumption.

[0311] refer to Figure 14 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 12 This is a specific implementation of the corresponding embodiment. For example, in a 4G application scenario, the mobility management network element and the access network device can be an MME and an eNB, respectively. In a 5G application scenario, the mobility management network element and the access network device can be an AMF and a gNB, respectively. In this embodiment, the terminal device is a satellite access type terminal device.

[0312] The method includes the following steps: In step 1401, the mobility management network element determines, based on the satellite coverage information of the terminal device, that the terminal device will soon be without satellite network coverage, and then sends an indication message to the access network device. Correspondingly, the access network device receives the indication message.

[0313] Optionally, the location of the terminal device is fixed or its movement trajectory is fixed.

[0314] As one implementation method, the mobility management network element can receive satellite coverage information of the terminal device from the access network device, a third party, or the terminal device. As another implementation method, the mobility management network element can receive ephemeris information of the cell from the access network device, a third party, or the terminal device, and then determine the satellite coverage information of the terminal device based on the ephemeris information of the cell.

[0315] This instruction tells the access network device to execute the terminal device release procedure. In 4G, the terminal device release procedure refers to the S1 release procedure. In 5G, the terminal device release procedure refers to the access network (AN) release procedure.

[0316] Step 1401 is an optional step.

[0317] Step 1402: The access network device sends a UE context release request to the mobility management network element. Correspondingly, the mobility management network element receives the UE context release request.

[0318] The UE context release request is used to request the mobility management element to release the UE context, so that the mobility management element can release the connection with the terminal device and allow the terminal device to enter the idle state.

[0319] As one implementation method, if step 1401 is executed, the above indication information triggers the access network device to execute step 1402.

[0320] As another implementation method, if step 1401 is not executed, the access network device can determine that the terminal device will soon have no satellite network coverage based on the satellite coverage information of the terminal device, and then trigger the access network device to execute step 1402.

[0321] As another implementation method, if step 1401 above is not performed, the access network device may trigger the execution of step 1402 for other reasons, including but not limited to: the terminal device is not running a service, the operator's operation and maintenance system intervention (O&M Intervention) or an unknown error (Unspecified Failure).

[0322] Optionally, in 4G, after receiving a UE context release request, the Mobility Management Element (MME) can also request the Serving Gateway (S-GW) to release bearer resources. In 5G, after receiving a UE context release request, the Mobility Management Element (AMF) can also request the SMF to release bearer resources.

[0323] Step 1403: The mobility management network element determines the periodic TAU period or periodic registration period based on the satellite coverage information of the terminal device.

[0324] Optionally, if the mobility management network element determines that the terminal device is a satellite access type terminal device, the mobility management network element can determine the periodic TAU period or the periodic registration period based on the satellite coverage information of the terminal device.

[0325] In 4G, the Mobility Management Element (MME) determines the periodic Registration and Unlocking (TAU) period, which can be represented by a periodic TAU timer in specific implementations. In 5G, the Mobility Management Element (AMF) determines the periodic Registration and Unlocking (AU) period, which can also be represented by a periodic Registration and Unlocking (AU) timer in specific implementations.

[0326] The periodic TAU period includes the time period during which the terminal device is not covered by the satellite network, and the periodic registration period includes the time period during which the terminal device is not covered by the satellite network. This ensures that when the terminal device is not covered by the satellite network, it will not perform the periodic TAU process or the periodic registration process, and the terminal device will remain in a dormant state. That is, the time period from when the terminal device enters the idle state until the periodic TAU timer or the periodic registration timer expires includes the time period during which the terminal device is not covered by the satellite network.

[0327] Optionally, the mobility management network element also determines a first duration, which refers to the duration after the terminal device enters the idle state and before entering the sleep state. This first duration can also be referred to as the active time of the terminal device. When the terminal device is in the active state, the network can paging the terminal device from the idle state to the connected state.

[0328] In step 1404, the mobility management network element sends a reconfiguration command to the terminal device. This reconfiguration command includes a periodic TAU period or a periodic registration period. The terminal device then receives the reconfiguration command.

[0329] Optionally, the reconfiguration command may also include the duration for which the terminal device is active.

[0330] Optionally, the reconfiguration command may also include a reason value, which is satellite discontinuous coverage. Optionally, the reason value may also indicate that the terminal device should not perform uplink transmissions during sleep periods. Here, uplink transmissions include the transmission of uplink service data and / or uplink signaling.

[0331] In step 1405, the terminal device sends a reconfiguration response to the mobility management network element. Correspondingly, the mobility management network element receives the reconfiguration response.

[0332] In 4G, the reconfiguration command can be a GUTI Reallocation Command, which includes a periodic TAU period and optionally a first duration and / or a reason value. The reconfiguration response can be a GUTI Reallocation Complete message.

[0333] In 4G, the reconfiguration command can be a UE Configuration Update Command, which includes a periodic registration period and optionally a first duration and / or a reason value. The reconfiguration response can be a UE Configuration Update Complete message.

[0334] Steps 1404 and 1405 above are optional steps.

[0335] Step 1406: The mobility management network element sends a UE context release command to the access network device. Correspondingly, the access network device receives the UE context release command.

[0336] This UE context release command is used to instruct the access network device to release the UE context.

[0337] If steps 1404 and 1405 above are not executed, the UE context release command includes a periodic TAU period or a periodic registration period, and optionally also includes a first duration and / or a reason value.

[0338] Step 1407: The access network device sends an RRC connection release request to the terminal device. Correspondingly, the terminal device receives the RRC connection release request.

[0339] If the aforementioned UE context release command includes a periodic TAU period or a periodic registration period, then the RRC connection release request includes the periodic TAU period or the periodic registration period. If the aforementioned UE context release command also includes a first duration and / or a reason value, then the RRC connection release request also includes the first duration and / or the reason value.

[0340] Step 1408: The access network device sends a UE context release complete message to the mobility management network element. Correspondingly, the mobility management network element receives the UE context release complete message.

[0341] Step 1408 is optional.

[0342] Step 1409: Based on the cause value, the terminal device does not perform uplink transmission during the time period corresponding to the periodic TAU cycle or the periodic registration cycle.

[0343] In other words, when there is an uplink transmission requirement, the terminal device will not perform uplink transmission during the time period corresponding to the periodic TAU cycle or periodic registration cycle, based on the reason value.

[0344] Step 1409 is an optional step.

[0345] If step 1404 or step 1407 above contains a cause value, then step 1409 is executed.

[0346] According to the above scheme, in the release process of the terminal device, when the terminal device enters the idle state, the periodic TAU cycle or periodic registration cycle update is triggered, thereby ensuring that the terminal device enters the idle state and hibernates during the time period when it is not covered by the satellite network, thereby reducing the power consumption of the terminal device.

[0347] refer to Figure 15 This is a flowchart illustrating a communication method provided in an embodiment of this application. The solution is as described above. Figure 12 This is a specific implementation of the corresponding embodiment. For example, in a 4G application scenario, the mobility management network element and the access network device can be an MME and an eNB, respectively. In a 5G application scenario, the mobility management network element and the access network device can be an AMF and a gNB, respectively.

[0348] The method includes the following steps: Step 1501: Based on its satellite coverage information, if the terminal device determines that it will soon be without satellite network coverage, it sends a TAU request or a Mobility Registration Update request to the Mobility Management Network element through the access network device. The Mobility Management Network element then receives the TAU request or Mobility Registration Update request.

[0349] Optionally, the location of the terminal device is fixed or its movement trajectory is fixed.

[0350] As one implementation method, the terminal device can receive its satellite coverage information from access network equipment, a third party, or core network equipment. As another implementation method, the terminal device can receive cell ephemeris information from access network equipment, a third party, or core network equipment, and then determine its satellite coverage information based on that cell ephemeris information.

[0351] In 4G, the access network device sends a TAU request to the Mobility Management Element (MME). In 5G, the access network device sends a Mobile Registration Update Request to the Mobility Management Element (AMF).

[0352] Step 1502 is the same as step 1403 above.

[0353] Step 1503: The mobility management network element sends a TAU acceptance message or a mobile registration update acceptance message to the terminal device through the access network equipment. The TAU acceptance message contains a periodic TAU period, or the mobile registration update acceptance message contains a periodic registration period. Correspondingly, the terminal device receives the TAU acceptance message or the mobile registration update acceptance message.

[0354] In 4G, the access network device sends a TAU request to the Mobility Management Element (MME), and the MME correspondingly sends a TAU acceptance message to the access network device. In 5G, the access network device sends a Mobile Registration Update Request to the Mobility Management Element (AMF), and the AMF correspondingly sends a Mobile Registration Update Accept message to the access network device.

[0355] Optionally, the TAU receiving message or mobile registration update receiving message may also include a first duration, the meaning of which is described in step 1403.

[0356] Optionally, the TAU acceptance message or mobile registration update acceptance message may also include a reason value, the meaning of which is described in step 1403.

[0357] Step 1504: Based on the cause value, the terminal device does not perform uplink transmission during the time period corresponding to the periodic TAU cycle or the periodic registration cycle.

[0358] In other words, when there is an uplink transmission requirement, the terminal device will not perform uplink transmission during the time period corresponding to the periodic TAU cycle or periodic registration cycle, based on the reason value.

[0359] Step 1504 is optional. If step 1503 contains a cause value, then step 1504 is executed.

[0360] According to the above scheme, before the terminal device is about to lose satellite network coverage, the terminal device triggers a periodic TAU process or a periodic registration process. This allows the mobility management network element to determine the periodic TAU period or periodic registration period based on the satellite coverage information of the terminal device. The time period corresponding to the periodic TAU period or periodic registration period includes the time period when the terminal device is not covered by the satellite network. This ensures that after the terminal device enters the idle state, it will hibernate during the time period when it is not covered by the satellite network, thereby reducing the power consumption of the terminal device.

[0361] Referring to Figure 16(a), a flowchart illustrating a communication method provided in an embodiment of this application is shown. This solution is as described above. Figure 4 A specific implementation of the corresponding embodiment. The method includes the following steps: Step 1601a: The terminal device obtains the satellite coverage information of the terminal device.

[0362] Optionally, the location of the terminal device is fixed or its movement trajectory is fixed.

[0363] As one implementation method, the terminal device can receive its satellite coverage information from access network equipment, third-party equipment, or core network equipment (such as mobility management network elements). As another implementation method, the terminal device can receive ephemeris information from access network equipment, third-party equipment, or core network equipment, and then determine its satellite coverage information based on that ephemeris information.

[0364] Specifically, when a terminal device receives its satellite coverage information or ephemeris information from an access network device, this can be achieved through the following method: The terminal device receives an RRC message from the access network device, and this RRC message includes the terminal device's satellite coverage information or ephemeris information. This RRC message can be an RRC reconfiguration message or a broadcast message.

[0365] Specifically, when a terminal device receives its satellite coverage information or ephemeris information from a mobility management network element, this can be achieved through the following method: The terminal device receives a NAS message from the mobility management network element, the NAS message including the terminal device's satellite coverage information or ephemeris information. Optionally, the NAS message may also include one or more of eDRX cycles, periodic TAU cycles, or periodic registration cycles. The NAS message can be a registration acceptance message, an attach acceptance message, or a TAU acceptance message.

[0366] The satellite coverage information of this terminal device can also be ephemeris information.

[0367] Step 1602a: The terminal device determines whether to initiate a periodic TAU, periodic registration, or transmit uplink data based on the satellite coverage information of the terminal device.

[0368] Specifically, the terminal device determines whether it is covered by the satellite network based on its satellite coverage information, that is, whether the terminal device is currently covered by the satellite network. When the terminal device is covered by the satellite network, it initiates periodic TAU, periodic registration, or transmits uplink data. When the terminal device is not covered by the satellite network, it does not initiate periodic TAU, periodic registration, or transmit uplink data.

[0369] As one implementation method, the terminal device can also receive indication information from the access network device or mobility management network element. This indication information is used to instruct the terminal device to check the satellite network coverage when it has uplink transmission needs, and to perform uplink transmission based on the satellite network coverage. The uplink transmission needs here include, but are not limited to: periodic TAU, periodic registration, and uplink data transmission. When the terminal device receives this indication information, step 1602a can be: the terminal device determines whether to initiate periodic TAU, periodic registration, or transmit uplink data based on its satellite coverage information and the indication information. Specifically, when the terminal device is covered by the satellite network, it initiates periodic TAU, periodic registration, or transmits uplink data. When the terminal device is not covered by the satellite network, it does not initiate periodic TAU, periodic registration, or transmit uplink data.

[0370] According to the above scheme, when the terminal device is not covered by the satellite network, it will not perform uplink transmission even if there is an uplink transmission requirement. This can avoid unnecessary and invalid network connection operations such as cell scanning and cell selection, thereby saving the energy consumption of the terminal device.

[0371] Optionally, the embodiment corresponding to Figure 16(a) above can be applied to scenarios where the terminal device is not covered by the satellite network for a long period of time. This is because the periodic TAU or periodic registration period has a limit and cannot be very large. Therefore, when the terminal device is not covered by the satellite network for a long time, it is inevitable to perform periodic TAU or periodic registration. At this time, the terminal device is not covered by the satellite network, which will cause the terminal device to continuously perform cell scanning and cell selection, resulting in higher energy consumption. Therefore, in order to avoid unnecessary periodic TAU or periodic registration when the idle terminal device is not covered by the satellite network, in the embodiment corresponding to Figure 16(a) above, when the terminal device is not covered by the satellite network, the terminal device will not perform periodic TAU or periodic registration and uplink data transmission, thereby minimizing the signaling interaction between the terminal device and the mobility management network element and reducing the energy consumption of the terminal device.

[0372] Referring to Figure 16(b), a flowchart illustrating a communication method provided in an embodiment of this application is shown. This solution is as described above. Figure 4 A specific implementation of the corresponding embodiment. The method includes the following steps: Step 1601b: The mobility management network element obtains satellite coverage information of the terminal device.

[0373] As one implementation method, the mobility management network element can receive satellite coverage information of the terminal device from the terminal device, access network device or a third party, wherein the satellite coverage information of the terminal device can also be ephemeris information.

[0374] As another implementation method, the mobility management network element can receive ephemeris information from the terminal device, access network device or third party, and then determine the satellite coverage information of the terminal device based on the ephemeris information.

[0375] Step 1602b: The mobility management network element determines whether to perform deregistration (or deattachment) of the terminal device based on the satellite coverage information of the terminal device.

[0376] Specifically, when the deregistration timer (or deattachment timer) for the terminal device times out, the system determines whether to perform deregistration (or deattachment) based on the satellite coverage information of the terminal device. If the terminal device is covered by a satellite network, the mobility management element performs deregistration (or deattachment) on the terminal device. If the terminal device is not covered by a satellite network, the mobility management element does not perform deregistration (or deattachment) on the terminal device.

[0377] Not performing deregistration on the terminal device can be understood as keeping the terminal device's registration status unchanged. Similarly, not performing detachment on the terminal device can be understood as keeping the terminal device's attachment status unchanged, i.e., keeping the terminal device in EMM registration status. Optionally, not performing deregistration on the terminal device may occur in response to the terminal device not being covered by the satellite network.

[0378] According to the above scheme, by reducing the switching between registration and deregistration, or between attachment and detachment of the terminal device, the signaling interaction between the terminal device and the network can be reduced, thereby reducing the energy consumption of the terminal device.

[0379] As one implementation method, the embodiment corresponding to Figure 16(a) can be combined with the embodiment corresponding to Figure 16(b).

[0380] It is understood that, in order to implement the functions in the above embodiments, the mobility management network element, access network device, or terminal device includes hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0381] Figure 17 and Figure 18The diagram illustrates the possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of mobility management network elements, access network devices, or terminal devices in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be a mobility management network element, access network device, or terminal device, or it can be a module (such as a chip) applied to a mobility management network element, access network device, or terminal device.

[0382] like Figure 17 As shown, the communication device 1700 includes a processing unit 1710 and a transceiver unit 1720. The communication device 1700 is used to implement the functions of the mobility management network element, access network equipment, or terminal equipment in the above method embodiments.

[0383] In the first embodiment, the communication device is used to perform the operation of the mobility management network element. The processing unit 1710 is used to determine the sleep time information of the terminal device based on the satellite coverage information of the terminal device. The satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network. The sleep time period corresponding to the sleep time information includes the time period during which the terminal device is not covered by the satellite network. The transceiver unit 1720 is used to send the sleep time information to the terminal device.

[0384] In one possible implementation, the processing unit 1710 is configured to determine one or more of the eDRX cycle, periodic TAU cycle, or periodic registration cycle of the terminal device based on the satellite coverage information; wherein the sleep time information includes a sleep start time, which is located within the eDRX cycle, the periodic TAU cycle, or the periodic registration cycle.

[0385] In one possible implementation, the hibernation time information includes the hibernation start time and hibernation end time; or, the hibernation time information includes the hibernation start time and hibernation duration.

[0386] In one possible implementation, the processing unit 1710 is used to receive the satellite coverage information through the transceiver unit 1720; or, through the transceiver unit 1720, to receive the ephemeris information of the satellite cell where the terminal device is located, and to determine the satellite coverage information based on the ephemeris information.

[0387] In one possible implementation, the processing unit 1710 is used to determine whether the location of the terminal device is fixed or its movement trajectory is fixed.

[0388] In one possible implementation, the processing unit 1710 is configured to determine, based on the satellite coverage information, that the terminal device is not covered by the satellite network when the deregistration timer corresponding to the terminal device times out, and to determine that deregistration will not be performed on the terminal device.

[0389] In the second embodiment, the communication device is used to perform operations of mobility management network elements. The processing unit 1710 is used to determine, when the deregistration timer corresponding to the terminal device times out, based on the satellite coverage information of the terminal device, that the terminal device is not covered by the satellite network, the satellite coverage information indicating the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; and in response to the terminal device not being covered by the satellite network, to determine that deregistration or deattachment is not performed on the terminal device.

[0390] In one possible implementation, the transceiver unit 1720 is used to send first information to the terminal device, the first information indicating that the terminal device should perform uplink transmission according to the satellite network coverage when it has uplink transmission requirements.

[0391] In one possible implementation, the first information is the satellite coverage information; specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0392] In one possible implementation, the transceiver unit 1720 is used to send the satellite coverage information to the terminal device; the first information is specifically used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0393] In one possible implementation, the uplink transmission requirement includes one or more of periodic TAU, periodic registration, or uplink data transmission.

[0394] In one possible implementation, the processing unit 1710 is used to receive the satellite coverage information through the transceiver unit 1720; or, through the transceiver unit 1720, to receive the ephemeris information of the satellite cell where the terminal device is located, and to determine the satellite coverage information based on the ephemeris information.

[0395] In one possible implementation, the processing unit 1710 is used to determine whether the location of the terminal device is fixed or its movement trajectory is fixed.

[0396] In the third embodiment, the communication device is used to perform operations of a mobility management network element. The processing unit 1710 is used to determine satellite coverage information of a terminal device, the satellite coverage information indicating the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; and to determine a maximum waiting time based on the satellite coverage information, the maximum waiting time indicating the maximum duration for which the terminal device can be waited for.

[0397] In one possible implementation, the processing unit 1710 is used to determine that the terminal device is unreachable based on the satellite coverage information.

[0398] In one possible implementation, the processing unit 1710 is used to receive the satellite coverage information via the transceiver unit 1720.

[0399] In one possible implementation, the processing unit 1710 is used to receive ephemeris information of the satellite cell where the terminal device is located through the transceiver unit 1720; and determine the satellite coverage information based on the ephemeris information.

[0400] In one possible implementation, the processing unit 1710 is configured to send a paging message to the access network device via the transceiver unit 1720. The paging message includes the identification information of the terminal device and indicates that the terminal device is being paged. The transceiver unit 1720 also receives a first message from the access network device. The first message includes a paging failure indication and satellite coverage information of the terminal device. The paging failure indication indicates that the paging failure is due to the terminal device not being covered by the satellite network. Optionally, the paging failure indication further indicates that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0401] In one possible implementation, the processing unit 1710 is used to determine whether the location of the terminal device is fixed or its movement trajectory is fixed.

[0402] In the fourth embodiment, the communication device is used to perform operations of the terminal device. The transceiver unit 1720 is used to receive first information, which indicates that the terminal device should perform uplink transmission according to the satellite network coverage when it has uplink transmission needs. The processing unit 1710 is used to determine that uplink transmission should not be performed if the terminal device is not covered by the satellite network when it has uplink transmission needs and based on the first information.

[0403] In one possible implementation, the first information is satellite coverage information, which indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0404] In one possible implementation, the processing unit 1710 is configured to receive satellite coverage information through the transceiver unit 1720. The satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network. Specifically, the first information is used to instruct the terminal device to initiate uplink transmission based on the satellite coverage information when it has uplink transmission requirements.

[0405] In one possible implementation, the uplink transmission requirement includes one or more of periodic TAU, periodic registration, or uplink data transmission.

[0406] In the fifth embodiment, the communication device is used to perform operations on the terminal device. The transceiver unit 1720 is used to receive sleep time information. The sleep time period corresponding to the sleep time information includes the time period during which the terminal device is not covered by the satellite network. The sleep time information is determined based on the satellite coverage information of the terminal device. The satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network. The processing unit 1710 is used to perform sleep according to the sleep time information.

[0407] In one possible implementation, the sleep time information includes a sleep start time, which is located within the eDRX cycle of the terminal device, the periodic TAU cycle of the terminal device, or the periodic registration cycle of the terminal device.

[0408] In one possible implementation, the hibernation time information includes the hibernation start time and hibernation end time; or, the hibernation time information includes the hibernation start time and hibernation duration.

[0409] In the sixth embodiment, the communication device is used to perform the operation of the access network equipment. The processing unit 1710 is used to obtain satellite coverage information or ephemeris information of the satellite cell. The satellite coverage information indicates the time period during which the satellite cell is covered by the satellite network and / or the time period during which it is not covered by the satellite network. The transceiver unit 1720 is used to send the satellite coverage information or ephemeris information of the satellite cell to the mobility management network element.

[0410] In one possible implementation, the transceiver unit 1720 is used to send satellite coverage information or ephemeris information corresponding to the satellite cell of the access network device to the mobility management network element during the N2 interface establishment process.

[0411] In one possible implementation, the transceiver unit 1720 is used to send satellite coverage information or ephemeris information of the satellite cell where the terminal device is located to the mobility management network element during the registration process of the terminal device.

[0412] In one possible implementation, the transceiver unit 1720 is configured to receive a paging message from the mobility management network element, the paging message including the identification information of the terminal device, the paging message indicating that the terminal device is being paged; the processing unit 1710 is configured to determine that the terminal device is unreachable based on the satellite coverage information of the satellite cell where the terminal device is located, and send a first message to the mobility management network element through the transceiver unit 1720, the first message including a paging failure indication and the satellite coverage information of the terminal device, the paging failure indication indicating that the reason for the paging failure is that the terminal device is not covered by the satellite network, optionally, the paging failure indication further indicating that the mobility management network element needs to perform reachability determination / paging based on the satellite coverage information.

[0413] In the seventh embodiment, the communication device is used to perform operations of a mobility management network element. The processing unit 1710 is used to determine the periodic TAU period of the terminal device based on the satellite coverage information of the terminal device; the transceiver unit 1720 is used to send the periodic TAU period to the terminal device; or, the processing unit 1710 is used to determine the periodic registration period of the terminal device based on the satellite coverage information of the terminal device; the transceiver unit 1720 is used to send the periodic registration period to the terminal device; wherein the satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network.

[0414] In one possible implementation, the time period corresponding to the periodic TAU period includes the time period during which the terminal device is not covered by the satellite network; or, the time period corresponding to the periodic registration period includes the time period during which the terminal device is not covered by the satellite network.

[0415] In one possible implementation, the processing unit 1710 is further configured to send instruction information to the access network device via the transceiver unit 1720 based on the satellite coverage information, the instruction information instructing the access network device to perform the terminal device release procedure.

[0416] In one possible implementation, the processing unit 1710 is used to determine a first duration based on the satellite coverage information of the terminal device, the first duration being the duration after the terminal device enters the idle state and before it enters the sleep state; the transceiver unit 1720 is used to send the first duration to the terminal device.

[0417] In one possible implementation, the transceiver unit 1720 is also configured to send a cause value to the terminal device, the cause value being satellite discontinuous coverage.

[0418] In one possible implementation, the reason value is also used to instruct the terminal device not to perform uplink transmissions during sleep.

[0419] In one possible implementation, the transceiver unit 1720 is configured to send a GUTI reallocation command to the terminal device, the GUTI reallocation command including the periodic TAU period; or, send a TAU acceptance message to the terminal device, the TAU acceptance message including the periodic TAU period.

[0420] In one possible implementation, the transceiver unit 1720 is configured to send a configuration update command to the terminal device, the configuration update command including the periodic registration period; or, send a mobile registration update acceptance message to the terminal device, the mobile registration update acceptance message including the periodic registration period.

[0421] In the eighth embodiment, the communication device is used to perform operations on the terminal device. The transceiver unit 1720 is used to receive a periodic TAU period from the mobility management network element; the processing unit 1710 is used to perform a periodic TAU according to the periodic TAU period, wherein the time period corresponding to the periodic TAU period includes the time period during which the terminal device is not covered by the satellite network; or, the transceiver unit 1720 is used to receive a periodic registration period from the mobility management network element; the processing unit 1710 is used to perform a periodic registration according to the periodic registration period, wherein the time period corresponding to the periodic registration period includes the time period during which the terminal device is not covered by the satellite network.

[0422] In one possible implementation, the periodic TAU period or the periodic registration period is determined based on the satellite coverage information of the terminal device, which indicates the time periods during which the terminal device is covered by the satellite network and / or the time periods during which it is not covered by the satellite network.

[0423] In one possible implementation, the processing unit 1710 is configured to send a TAU request to the mobility management network element via the transceiver unit 1720 based on the satellite coverage information of the terminal device before the transceiver unit 1720 receives the periodic TAU period from the mobility management network element; or, before the transceiver unit 1720 receives the periodic registration period from the mobility management network element, send a mobile registration update request to the mobility management network element via the transceiver unit 1720 based on the satellite coverage information of the terminal device; wherein the satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network.

[0424] In one possible implementation, the transceiver unit 1720 is further configured to receive a first duration from the mobility management network element, the first duration being the duration after the terminal device enters the idle state and before entering the sleep state, and the first duration being determined based on the satellite coverage information of the terminal device.

[0425] In one possible implementation, the transceiver unit 1720 is used to receive a cause value from the mobility management network element, the cause value being satellite discontinuous coverage.

[0426] In one possible implementation, the cause value is also used to instruct the terminal device not to perform uplink transmission during sleep; when there is an uplink transmission requirement, it is determined not to perform uplink transmission based on the cause value.

[0427] In the ninth embodiment, the communication device is used to perform operations of the access network device. The processing unit 1710 is used to send a context release request to a mobility management network element (MLE) via a transceiver unit 1720 based on the satellite coverage information of the terminal device. The context release request requests the MLE to release the context of the terminal device. The satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network. The transceiver unit 1720 is also used to receive a periodic TAU period from the MLE and send the periodic TAU period to the terminal device. The time period corresponding to the periodic TAU period includes the time period during which the terminal device is not covered by the satellite network. Alternatively, the transceiver unit 1720 is also used to receive a periodic registration period from the MLE and send the periodic registration period to the terminal device. The time period corresponding to the periodic registration period includes the time period during which the terminal device is not covered by the satellite network.

[0428] A more detailed description of the processing unit 1710 and the transceiver unit 1720 can be obtained directly from the relevant descriptions in the above method embodiments, and will not be repeated here.

[0429] like Figure 18 As shown, the communication device 1800 includes a processor 1810. Optionally, the communication device 1800 may also include an interface circuit 1820. The processor 1810 and the interface circuit 1820 are coupled to each other. It is understood that the interface circuit 1820 can be a transceiver or an input / output interface. Optionally, the communication device 1800 may also include a memory 1830 for storing instructions executed by the processor 1810, or storing input data required by the processor 1810 to execute instructions, or storing data generated after the processor 1810 executes instructions.

[0430] When the communication device 1800 is used to implement the above method embodiment, the processor 1810 is used to implement the function of the processing unit 1710, and the interface circuit 1820 is used to implement the function of the transceiver unit 1730.

[0431] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0432] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which 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 disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. Of course, the processor and storage medium can also exist as discrete components in the base station or terminal.

[0433] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially 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 this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a base station, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can 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 can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0434] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0435] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0436] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, include: Determine the satellite coverage information of the terminal device, wherein the satellite coverage information indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; Based on the satellite coverage information, determine the maximum waiting time; The maximum waiting time is sent to the session management function network element. The maximum waiting time is used to determine the extended buffer time, which indicates the duration for which the user plane network element caches downlink data.

2. The method as described in claim 1, characterized in that, The method further includes: Based on the satellite coverage information, it is determined that the terminal device is unreachable.

3. The method as described in claim 1 or 2, characterized in that, The determination of satellite coverage information for the terminal device includes: Receive the satellite coverage information.

4. The method as described in claim 1 or 2, characterized in that, The determination of satellite coverage information for the terminal device includes: Receive ephemeris information of the satellite cell where the terminal device is located; The satellite coverage information is determined based on the ephemeris information.

5. The method as described in claims 1 to 4, characterized in that, The maximum waiting time is also used to indicate the maximum time that can be reached while waiting for the terminal device.

6. The method as described in claim 1 or 5, characterized in that, The method further includes: The periodic tracking area update (TAU) cycle of the terminal device is determined based on the satellite coverage information of the terminal device, and the periodic TAU cycle is sent to the terminal device. The time period corresponding to the periodic TAU cycle includes the time period during which the terminal device is not covered by the satellite network; or... The periodic registration period of the terminal device is determined based on the satellite coverage information of the terminal device, and the periodic registration period is sent to the terminal device. The time period corresponding to the periodic registration period includes the time period when the terminal device is not covered by the satellite network.

7. The method as described in claim 1 or 6, characterized in that, The method further includes: Based on the satellite coverage information of the terminal device, a first duration is determined, which is the duration after the terminal device enters the idle state and before it enters the sleep state; The first duration is sent to the terminal device.

8. A communication method, characterized in that, include: Receive satellite coverage information, which indicates the time period during which the terminal device is covered by the satellite network and / or the time period during which it is not covered by the satellite network; When there is an uplink transmission requirement, it is determined not to perform uplink transmission based on the satellite coverage information.

9. The method as described in claim 8, characterized in that, The step of determining not to perform uplink transmission based on the satellite coverage information includes: If, based on the satellite coverage information, it is determined that the terminal device is not covered by the satellite network, then it is determined that no uplink transmission will be performed.

10. The method as described in claim 8 or 9, characterized in that, The received satellite coverage information includes: Receive the satellite coverage information from the access network equipment or mobility management network element.

11. The method according to any one of claims 8 to 10, characterized in that, The uplink transmission requirements include one or more of periodic tracking area update (TAU), periodic registration, or uplink data transmission.

12. A communication method, characterized in that, include: Based on the satellite coverage information of the terminal device, determine when you will leave the satellite network coverage area; Send a Tracking Area Update (TAU) request or a Mobile Registration Update (MCO) request to the Mobility Management Network element; The satellite coverage information indicates the time periods during which the terminal device is covered by the satellite network and / or the time periods during which it is not covered by the satellite network.

13. The method as described in claim 12, characterized in that, The method further includes: Receive satellite coverage information from the access network device or the mobility management network element.

14. A communication device, characterized in that, It includes modules for performing the method of any one of claims 1 to 7, or modules for performing the method of any one of claims 8 to 11, or modules for performing the method of any one of claims 12 to 13.

15. A communication device, characterized in that, The device includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor is used to implement the method as described in any one of claims 1 to 7, or the method as described in any one of claims 8 to 11, or the method as described in any one of claims 12 to 13, through logic circuits or executing code instructions.

16. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 7, or the method as described in any one of claims 8 to 11, or the method as described in any one of claims 12 to 13.

17. A computer program product, characterized in that, The computer program product includes instructions that, when executed on a communication device, cause the communication device to perform the method of any one of claims 1 to 7, or the method of any one of claims 8 to 11, or the method of any one of claims 12 to 13.

18. A chip system, characterized in that, include: A processor for performing the method of any one of claims 1 to 7, or the method of any one of claims 8 to 11, or the method of any one of claims 12 to 13.

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