Communication method and apparatus

Abstract

The present application relates to the technical field of communications. Provided are a communication method and apparatus, which are used for solving the problem that, in non-terrestrial network communications, a called user terminal experiences paging failure and is unable to receive a call due to poor signal quality. The method comprises: receiving a first message, the first message being used for calling a terminal by means of a non-terrestrial network or for notifying the terminal of the presence of a communication service by means of the non-terrestrial network; and when a signal of the non-terrestrial network satisfies a first condition, sending a second message in response to the first message, the second message being used for establishing a communication connection with the non-terrestrial network, and the first condition comprising at least one of the following: the signal strength of the non-terrestrial network being greater than or equal to a first threshold; or the signal quality of the non-terrestrial network being greater than or equal to a second threshold.

Description

Communication method and apparatus

[0001] The present application claims priority from the Chinese Patent Application No. 202411302706.3 filed on September 14, 2024, and entitled "A communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

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

[0003] Non-Terrestrial Networks (NTN) communication can be implemented by means of satellite, high altitude platform station (HAPS) equipment and other non-terrestrial network equipment to provide communication services for terminals. In NTN communication, the distance between the terminal and the non-terrestrial network equipment such as satellite is usually far, and whether the terminal is in an open area, whether the terminal is blocked or the placement direction of the terminal has a great influence on the communication quality.

[0004] For example, in a scenario of implementing voice call service through satellite communication, a user uses a terminal to make a call, and the calling user can place the terminal in an open area, ensure that the terminal is not blocked, or adjust the placement direction of the terminal to be aligned with the satellite, so as to initiate the voice call service when the satellite signal is strong. However, for a scenario of using a terminal to answer a call, the network usually needs to page the terminal first, but if the terminal of the called user currently has poor satellite signal quality, cannot receive the paging message, or cannot respond to the paging message, paging failure may occur, and the call cannot be connected. SUMMARY

[0005] The present application provides a communication method and apparatus to solve the problem of paging failure of the terminal of the called user due to poor signal quality and the inability to connect the call in non-terrestrial network communication.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, a communication method is provided, which can be performed by a communication apparatus, which can be a terminal, or a module (such as a chip, chip system or circuit) in the terminal, or a module or software that can implement all or part of the functions of the terminal. The method comprises: receiving a first message, the first message being used to call the terminal through a non-terrestrial network, or to notify the terminal that there is a communication service through the non-terrestrial network; and in response to the first message, sending a second message for establishing a communication connection with the non-terrestrial network when a signal of the non-terrestrial network satisfies a first condition, the first condition comprising at least one of: a signal strength of the non-terrestrial network being greater than or equal to a first threshold; or a signal quality of the non-terrestrial network being greater than or equal to a second threshold.

[0008] In the above embodiments, for the scenario of non-terrestrial network communication, the network can send a specific type of message, such as the first message, to the terminal, which can be used to call the terminal through the non-terrestrial network, or to notify the terminal that there is a communication service through the non-terrestrial network, so as to remind the terminal user that there is a communication service, and the terminal can respond to the message and establish a communication connection with the non-terrestrial network, so as to solve the problem that the receiver of the communication service in the non-terrestrial network misses the communication service due to poor signal quality, improve the communication efficiency, and improve the user experience.

[0009] In an embodiment, the first message comprises indication information corresponding to an initiator of the communication service, the indication information being used to indicate whether the initiator belongs to a pre-configured user, or to indicate a second identifier corresponding to the initiator, the second identifier being telephone number information.

[0010] In the above embodiments, the network device can send the first message to the terminal, which can include indication information corresponding to the initiator of the communication service, so that the first message can remind the terminal user that there is a communication service, and notify the receiver of the relevant information of the initiator of the current communication service, so that the receiver can confirm whether to respond according to the notification, avoid missing the communication service due to poor non-terrestrial network state, improve the communication efficiency, and improve the user experience.

[0011] In an embodiment, the method further comprises: receiving a third message, the third message being used to indicate a communication service that has not been responded to, the third message comprising a second identifier corresponding to an initiator of the communication service, the second identifier being telephone number information.

[0012] In the above embodiment, the network device can further indicate, through the third message, telephone number information of the initiator corresponding to the unresponded communication service, for example, missed call information, so that the terminal can respond, such as redialing, according to the telephone number of the initiator, avoid missing the communication service due to poor non-terrestrial network state of the called party, improve communication efficiency, and improve user experience.

[0013] In an embodiment, the first message includes a first identifier corresponding to the terminal, and a length of the first identifier is less than a first value, and the first value is a length of an identifier of the terminal carried in a paging message used for paging the terminal.

[0014] In the above embodiment, the first message can include a specific identifier for indicating the terminal with the communication service, for example, a first identifier. The terminal receiving the first message can determine whether the first message is a call to itself by comparing the first identifier carried in the first message with an identifier configured for the terminal by the core network, so as to determine whether the first message is a call to itself. In addition, the first identifier is different from the terminal identifier carried in the existing paging message, and the length of the first identifier is less than the length of the terminal identifier carried in the paging message, so as to save signaling overhead.

[0015] In an embodiment, before receiving the first message, the method further includes receiving a fourth message, and the fourth message is used to instruct the terminal to detect the first message.

[0016] In the above embodiment, the network device can send a fourth message to the terminal, which is used to instruct the terminal to start the function of detecting the first message, that is, the first message can be used as an activation indication of sending the first message, so that the terminal can determine that the network will call the terminal through broadcasting the first message when the non-terrestrial network state is poor in the future, and the terminal can start detecting the first message under preset conditions, so as to avoid missing the communication service due to poor non-terrestrial network state, improve communication efficiency, and improve user experience.

[0017] In an embodiment, the fourth message includes a first time length, and the first time length is used to indicate a maximum time length between receiving the first message and sending the second message by the terminal.

[0018] In the above embodiment, the network device can further include the first time length in the indication of activating the first message sent to the terminal, that is, the response time length of the first message, which is used to indicate that when the terminal is paged by the network through the first message in the future, the terminal can respond to the current communication service within the first time length, otherwise, the network device will terminate the current communication service after waiting for a timeout, so as to improve the flexibility of processing the communication service and improve the communication efficiency.

[0019] In an implementation, before receiving the first message, the method further includes: sending a fifth message, the fifth message being used to indicate that the terminal has the capability of detecting the first message.

[0020] In the above implementation, the terminal can report to the network device that it has the capability of detecting the first message, so that the network device can determine whether the terminal can be called by the first message in the future according to the capability of the terminal, or determine whether to activate the function of calling the terminal by the first message, thereby improving the flexibility of communication service processing and improving the communication efficiency.

[0021] In an implementation, detecting the first message includes: when the terminal is in an idle state or an inactive state, and it is determined that the signal reception index of the non-terrestrial network meets a second condition, detecting the first message, the second condition including at least one of: the signal strength of the non-terrestrial network is less than the first threshold; or the signal quality of the non-terrestrial network is less than the second threshold.

[0022] In the above implementation, when the terminal is in an idle state or an inactive state, and the signal reception index of the non-terrestrial network of the terminal meets the preconfigured second condition, i.e., the terminal determines that the non-terrestrial network state is poor, the network can call the terminal by the first message. The terminal can start to detect the first message, thereby avoiding the situation that the user misses the communication service due to the poor non-terrestrial network state, improving the communication efficiency and the user experience.

[0023] In an implementation, the second message is a service request message used to request to establish a session corresponding to the communication service; or the second message is a registration request message used to register the terminal to the network.

[0024] In the above implementation, if the first message supports establishing a session corresponding to the communication service of the terminal, when the non-terrestrial network state of the terminal is good, the terminal can send a second message, i.e., a service request message, to the network device in response to the first message, to request to establish a session corresponding to the communication service of the terminal, thereby realizing calling the terminal by the first message and successfully establishing the communication service session of the terminal, such as a telephone connection, avoiding the situation that the user misses the communication service due to the poor non-terrestrial network state, and improving the communication efficiency. Or, if the first message does not support establishing a session corresponding to the communication service of the terminal, when the non-terrestrial network state of the terminal is good, the terminal can send a second message, i.e., a registration request message, to the network device in response to the first message, to request to register to the core network, thereby obtaining the related information of the calling party of the unresponded communication service, such as missed call reminding information, avoiding the situation that the user misses the communication service due to the poor non-terrestrial network state, improving the communication efficiency, and improving the user experience.

[0025] In an embodiment, after receiving the first message, the method further comprises: starting, by the terminal, a first timer, wherein the first timer corresponds to a first time length, and the first timer is used to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal before the first timer expires.

[0026] In the above embodiment, after receiving the first message, the terminal can start a corresponding first timer according to the configured first time length, to remind the user to adjust the non-terrestrial network signal receiving scenario of the terminal within the response time length corresponding to the first message, so as to improve the non-terrestrial network quality of the terminal, thereby enabling the terminal to send a response message corresponding to the first message, such as a second message, to the network device, thereby avoiding the situation that the user misses the communication service due to poor non-terrestrial network state, improving communication efficiency, and improving user experience.

[0027] In an embodiment, sending the second message comprises: when the first timer does not expire and the signal of the non-terrestrial network satisfies the first condition, sending the second message, wherein the second message is a service request message.

[0028] In the above embodiment, if the first message supports establishing a session corresponding to the communication service of the terminal, the terminal can send a second message, i.e., a service request message, to the network device in response to the first message when the first timer does not expire and the current non-terrestrial network state satisfies the first condition, to request to establish a session corresponding to the communication service of the terminal, thereby enabling the terminal to be called through the first message and successfully establishing a communication service session of the terminal, such as a telephone connection, thereby avoiding the situation that the user misses the communication service due to poor non-terrestrial network state, and improving communication efficiency.

[0029] In an embodiment, sending the second message comprises: when the first timer expires and the signal of the non-terrestrial network satisfies the first condition, sending the second message, wherein the second message is a registration request message.

[0030] In the above embodiment, the terminal can send a second message, i.e., a registration request message, to the network device in response to the first message when the first timer expires and the current non-terrestrial network state satisfies the first condition, to request to register to the core network, thereby enabling the terminal to obtain the information of the calling party of the unresponded communication service, such as missed call reminder information, thereby avoiding the situation that the user misses the communication service due to poor non-terrestrial network state, improving communication efficiency, and improving user experience.

[0031] In an implementation, the method further includes: in response to the first message, the terminal rings and displays a notification, the ringing and / or the notification are used to indicate that the terminal has the communication service, and the notification is further used to prompt a user to adjust a non-terrestrial network signal receiving scenario of the terminal.

[0032] In the above implementation, after the terminal receives the first message, the terminal can ring and display a notification in response to the first message, which is used to remind the user that there is currently a communication service. Optionally, the terminal can display a reminder notification through an interface to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal, such as aiming the mobile phone at the window outside, taking the mobile phone outside, or adjusting the placement posture of the mobile phone, so that the non-terrestrial network signal of the terminal is better, and the terminal can send a response message corresponding to the first message to the network device, thereby being able to respond to the current communication service of the terminal, avoiding the case that the user cannot respond due to the poor non-terrestrial network state, and the network waiting timeout causes the terminal to fail to learn the communication service, thereby improving the communication efficiency and improving the user experience.

[0033] In a second aspect, a communication method is provided, which can be performed by a communication apparatus. The communication apparatus can be a network device, or a module (such as a chip, a chip system, or a circuit) in the network device, or a module or software that can implement all or part of the functions of the network device. For example, the communication apparatus can be a non-terrestrial access network device or a mobility management device of a core network. The method includes: when a terminal is in an idle state or an inactive state, sending a first message, the first message being used to call the terminal through a non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network, wherein the terminal communicates through the non-terrestrial network; and receiving a second message, the second message being used to establish a communication connection between the terminal and the non-terrestrial network, wherein the second message is sent by the terminal in response to the first message when a signal of the non-terrestrial network meets a first condition, and the first condition includes at least one of the following: a signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or a signal quality of the non-terrestrial network is greater than or equal to a second threshold value.

[0034] In an implementation, the first message includes a first identifier corresponding to the terminal, and a length of the first identifier is less than a first value, and the first value is a length of an identifier of the terminal carried in a paging message used to page the terminal.

[0035] In an implementation, the sending of the first message includes: sending the first message according to a first strategy, and the first strategy includes at least one of the following: calling the terminal through the first message in the non-terrestrial network, or calling the terminal through the first message after failing to call the terminal through a paging message in the non-terrestrial network, or calling the terminal by alternately sending the paging message and the first message in the non-terrestrial network.

[0036] In the above embodiments, the network device can send the first message to call the terminal according to a configured policy. For example, according to a configured first policy, the network device can call the terminal through only the first message when the terminal is in a non-terrestrial network; or the network device can call the terminal through an existing paging message first when the terminal is in a non-terrestrial network, and call the terminal through the first message again when the terminal does not respond to the paging message for a plurality of times; or the network device can call the terminal by alternately sending a paging message and the first message when the terminal is in a non-terrestrial network, for example, sending the paging message once and then sending the first message once, or sending the paging message twice and then sending the first message twice, and so on. The embodiments provided in the present application for calling the terminal through the first message are flexible, the network device can flexibly configure a corresponding policy according to needs and update the policy in real time, the efficiency of calling the terminal by the network can be improved, the communication efficiency can be improved, and the user experience can be improved.

[0037] In an embodiment, the method further includes receiving a sixth message, the sixth message including indication information corresponding to an initiator of the communication service, the indication information indicating whether the initiator belongs to a pre-configured user or indicating a second identifier corresponding to the initiator, the second identifier being telephone number information.

[0038] In an embodiment, the first message includes indication information corresponding to an initiator of the communication service.

[0039] In an embodiment, the method further includes sending a third message to the terminal, the third message being used to indicate that there is an unresponded communication service for the terminal, the third message including a second identifier corresponding to an initiator of the communication service, the second identifier being telephone number information.

[0040] In an embodiment, before sending the first message, the method further includes sending a fourth message to the terminal, the fourth message being used to instruct the terminal to detect the first message.

[0041] In an embodiment, the fourth message includes a first time length, the first time length being used to indicate a maximum time length between receiving the first message and sending the second message by the terminal.

[0042] In an embodiment, before sending the first message, the method further includes receiving a fifth message from the terminal, the fifth message being used to indicate that the terminal has the capability of detecting the first message.

[0043] In an implementation, the second message is a service request message for requesting establishment of a session corresponding to the communication service, or the second message is a registration request message for registering the terminal to the network.

[0044] In a third aspect, a communication apparatus is provided for implementing the method in the above aspects. The communication apparatus can be a device for implementing the method in the first or second aspect, or a node or equipment comprising the device, or a module in the device, such as a chip, chip system or circuit, or a logic node, logic module or software capable of implementing part or all of the functions.

[0045] The apparatus includes modules, units, or means for implementing the corresponding functions of the method described above, which can be implemented by hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0046] In a possible implementation, the apparatus can include a processing module and a transceiver module. The processing module can be configured to implement the processing functions in any of the above aspects and any possible implementation. The processing module can be, for example, a processor. The transceiver module, which can also be referred to as a transceiving unit, is configured to implement the functions of transmitting and / or receiving in any of the above aspects and any possible implementation. The transceiver module can include a transceiving circuit, a transceiver, a transceiver, or a communication interface.

[0047] In a possible implementation, the transceiver module includes a transmitting module and a receiving module, which are configured to implement the functions of transmitting and receiving in any of the above aspects and any possible implementation.

[0048] In a fourth aspect, a communication apparatus is provided, which includes a processor, and the processor is configured to couple with a memory and read instructions in the memory, and execute the method in any of the above aspects according to the instructions. The communication apparatus can be the device in the first or second aspect, or a node or equipment comprising the device, or a module in the device, such as a chip, chip system or circuit, or a logic node, logic module or software capable of implementing part or all of the functions.

[0049] In a possible implementation, the communication apparatus further includes a memory configured to store program instructions and / or data. Optionally, the memory and the processor are integrated together.

[0050] In a possible implementation, the communication apparatus is a chip or chip system. Optionally, when the communication apparatus is a chip system, it can be composed of a chip or comprise a chip and other discrete devices.

[0051] In a fifth aspect, a communication apparatus is provided, which comprises a processor and an interface circuit; the interface circuit is configured to receive a computer program or instructions and transmit them to the processor; the processor is configured to execute the computer program or instructions, so that the communication apparatus performs the method in any of the preceding aspects. The communication apparatus can be the apparatus in the first aspect or the second aspect, or a node or device comprising the apparatus, or a module such as a chip, chip system or circuit in the apparatus, or a logic node, logic module or software capable of implementing part or all of the functions.

[0052] In a possible implementation, the communication apparatus is a chip or a chip system. Optionally, when the communication apparatus is a chip system, it can be composed of a chip or comprise a chip and other discrete devices.

[0053] In a sixth aspect, a computer readable storage medium is provided, which stores instructions, when executed on a computer, causes the computer to perform the method in any of the preceding aspects.

[0054] In a seventh aspect, a computer program product is provided, which comprises instructions, when executed on a computer, causes the computer to perform the method in any of the preceding aspects.

[0055] In an eighth aspect, a communication system is provided, which comprises a terminal performing the method in the first aspect and a network device performing the method in the second aspect. For example, the network device performing the method in the second aspect can be a non-terrestrial access network device or a mobility management device.

[0056] The technical effects brought by any possible implementation of the second aspect to the eighth aspect can be referred to the technical effects brought by the different possible implementations of the first aspect, which will not be repeated here.

[0057] It can be understood that the solutions in each aspect can be combined, provided that the solutions are not contradictory. BRIEF DESCRIPTION OF DRAWINGS

[0058] FIG. 1 is a schematic diagram of an architecture of a communication system provided by an embodiment of the present application;

[0059] FIG. 2 is a schematic diagram of another architecture of a communication system provided by an embodiment of the present application;

[0060] FIG. 3 is a schematic diagram of another architecture of a communication system provided by an embodiment of the present application;

[0061] FIG. 4 is a schematic diagram of a structure of a communication apparatus provided by an embodiment of the present application;

[0062] FIG. 5 is a flow diagram of a communication method according to an embodiment of the present application;

[0063] FIG. 6 is a diagram of several embodiments of a communication method according to an embodiment of the present application;

[0064] FIGS. 7-11 are flow diagrams of specific embodiments of a communication method according to an embodiment of the present application;

[0065] FIG. 12 is a diagram of another communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0066] Hereinafter, the terms “first” and “second” are used only for the purpose of description, and should not be construed as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first” and “second” can explicitly or implicitly include one or more of the features. In the description of the embodiments, the meaning of “a plurality of” is two or more, unless otherwise specified.

[0067] It should be noted that in the present application, the words “exemplary” or “for example” are used to mean serving as an example, instance, or illustration. Any embodiment or design scheme described as “exemplary” or “for example” in the present application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Rather, the use of “exemplary” or “for example” is intended to present relevant concepts in a concrete manner.

[0068] The technical solutions in the embodiments of the present application will be described clearly and completely in the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0069] First, the implementation environment and application scenario of the embodiments of the present application are briefly introduced.

[0070] The communication method provided by the embodiments of the present application can be applied to a fourth generation (4th generation, 4G) communication system, such as a long term evolution (long term evolution, LTE) communication system, and can also be applied to a fifth generation (5th generation, 5G) communication system, such as a 5G new radio (new radio, NR) communication system, or various communication systems evolved after 5G, future communication systems. Among them, the 4G core network is called evolved packet core (Evolved Packet Core, EPC), and the 5G core network is called 5G core network (5G Core, 5GC).

[0071] FIG. 1 shows a network architecture to which the present application is applicable. In FIG. 1, the interaction between network functions (NFs) and entities and the corresponding interfaces are shown with respect to a network service architecture of a 5th generation (5G) mobile communication system. The 3rd generation partnership project (3GPP) service-based architecture (SBA) of the 5G system includes network functions and entities such as a user equipment (UE), at least one access network (AN) or radio access network (RAN) node, a user plane function (UPF), a data network (DN), an access and mobility management function (AMF), a session management function (SMF), a policy control function (PCF), an application function (AF), a unified data management (UDM), a network exposure function (NEF), a unified data repository (UDR), and a NF repository function (NRF).

[0072] The UE, the (radio) access network (RAN) node, the UPF, and the DN are generally referred to as user plane network functions and entities (or user plane network elements), and the other parts are generally referred to as control plane network functions and entities (or control plane network elements). The control plane network elements are defined by the 3GPP to handle functions within a network, and the control plane network elements have 3GPP-defined functional behavior and 3GPP-defined interfaces. The NFs can be implemented as a network element running on proprietary hardware, or a software instance running on proprietary hardware, or a virtual function instantiated on a suitable platform, such as a cloud infrastructure.

[0073] The main functions of each network function are described below.

[0074] Among them, the user plane network function in the communication system includes:

[0075] (R)AN node: The (R)AN can be an AN or a RAN, and can also be referred to as an access network device, an access network node, a RAN entity, or an access node, etc., which constitutes a part of the communication system and helps the terminal device to access the communication network. For example, the (R)AN can be various forms of base stations, such as macro base stations, micro base stations, radio controllers, relay stations, access points, vehicle-mounted devices, wearable devices, or network devices in future evolved public land mobile networks (PLMN), or non-terrestrial access network devices, etc., such as base stations deployed on satellites. The (R)AN is mainly responsible for radio resource management, quality of service management, data compression and encryption, etc. on the air interface side.

[0076] In addition, the (R)AN node can also be an access node in an open access network (open RAN, O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system, and can also be an access node in a communication system that integrates two or more of the above systems.

[0077] In a possible scenario, the RAN node can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a base station in a future mobile communication system (next generation NodeB, gNB), or an access node in a WiFi system, etc. The RAN node can be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, the RAN node can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in the vehicle to everything (V2X) technology can be a road side unit (RSU). All or part of the functions of the RAN node in this application can also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform such as a cloud platform. The RAN node in this application can also be a logical node, a logical module or software that can implement all or part of the functions of the RAN node.

[0078] In another possible scenario, a terminal device is assisted by multiple RAN nodes to implement wireless access in cooperation, and different RAN nodes respectively implement part of functions of a base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0079] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0080] UE: can also be referred to as a terminal, a terminal device, a mobile station (MS), a mobile terminal (MT), etc., or a device used to provide voice or data connectivity to a user, or an Internet of Things device. For example, a terminal device includes a handheld device having wireless connection functionality, a vehicle-mounted device, etc. At present, a terminal device can be: a mobile phone, a tablet computer, a notebook computer, a palm computer, a mobile Internet device (MID), a wearable device (such as a smart watch, a smart bracelet, a pedometer, smart glasses, etc.), a vehicle-mounted device (such as a car, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a satellite terminal, a virtual reality (VR) device, an augmented reality (AR) device, a smart point of sale (POS) machine, a customer-premises equipment (CPE), a light UE, a reduced capability UE (REDCAP UE), a wireless terminal in industrial control, a smart home device (such as a refrigerator, a television, an air conditioner, an electricity meter, etc.), a smart robot, a mechanical arm, a workshop device, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, or a wireless terminal in a smart home, a flight device (such as a smart robot, a hot air balloon, a drone, an airplane), etc. A terminal device can also be a vehicle device, such as a whole vehicle device, a vehicle-mounted module, a vehicle-mounted chip, an on board unit (OBU), or a telematics box (T-BOX), etc. A terminal device can also be other devices with terminal functions, for example, a device that plays a terminal function in D2D communication.

[0081] Embodiments of the present application do not limit the device form of the terminal, and the device used to implement the function of the terminal device can be a terminal device, or can be a device capable of supporting the terminal device to implement the function, such as a chip system. The device can be installed in the terminal device or used in matching with the terminal device. In embodiments of the present application, a chip system can be composed of a chip, or can include a chip and other discrete devices. All or part of the functions of the terminal device in the present application can also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform (such as a cloud platform).

[0082] UPF: mainly responsible for forwarding and receiving user plane data. The UPF can receive downlink data from the DN and then transmit the downlink data to the UE through the (R)AN. The UPF can also receive uplink data from the UE through the (R)AN and then forward the uplink data to the DN.

[0083] DN: For example, the DN can be an operator service network, an Internet access, or a third-party service network. The DN can interact with the UE through a PDU session. Among them, the PDU session can be divided into multiple types, such as Internet Protocol version 4 (IPv4), IPv6, etc.

[0084] In addition, the control plane network functions in the communication system include:

[0085] AMF: mainly responsible for processing control plane messages, responsible for mobility management of terminal devices, including mobile state management, allocation of user temporary identity, authentication and authorization of users. For example, access control, mobility management, registration and deregistration, and network element selection, etc.

[0086] SMF: mainly used for session management, session establishment, (private) Internet Protocol (IP) address allocation and management of UEs, responsible for session establishment, modification and release, quality of service (QoS) control, etc.

[0087] UDM: mainly used for authentication credit processing, responsible for managing subscription data, user identification processing, access authorization, registration / mobility management, subscription management, and short message management, etc. For example, when the subscription data of the user is modified, the UDM is responsible for notifying the corresponding network element.

[0088] NEF: mainly used for providing corresponding security guarantees to ensure the security of external applications to the communication network, providing external application QoS customization capability exposure, mobility state event subscription, AF request distribution, etc.

[0089] NRF: mainly used for providing internal / external addressing functions, etc.

[0090] AF: mainly used for sending application impact data routing information to the network side, interacting with the policy framework through the network exposure function network element for policy control, etc.

[0091] PCF: the main function is a policy decision point, provides rules based on traffic data flow or application detection, QoS and flow-based charging control, etc. And can provide policy to AMF, SMF, such as QoS policy, slice selection policy, etc. As in the embodiments of the present application, the PCF can provide the AMF or the SMF with relevant configuration information or policy information about the border area, so that the AMF or the SMF can determine whether the terminal is in the border area according to the configuration information or policy information provided by the PCF, thereby determining whether to trigger a new connection establishment.

[0092] In addition, Figure 2 shows another network architecture applicable to the present application, which takes the network service architecture of a 4G system as an example. The network functions and entities contained in the 4G system mainly include: UE, eNodeB, mobility management entity (MME), serving gateway (Serving Gateway, S-GW), packet data network gateway (Packet Data Network Gateway, PDN-GW or P-GW), home subscription server (Home Subscription Server, HSS), policy and charging rule function (Policy and Charging Rule Function, PCRF) and service capability exposure function (Service Capability Exposure Function, SCEF) and the like.

[0093] Among them, MME: the key control node of the LTE access network, which is responsible for the positioning of the idle mode UE (User Equipment), the paging process, including relays.

[0094] S-GW: user plane access service gateway of EPC network, responsible for user data forwarding.

[0095] P-GW: used to provide user session management and bearer control, data forwarding, IP address allocation and non-3GPP user access functions. It is the anchor point of user access to the packet data network (Packet Data Network, PDN).

[0096] HSS: used to process information including: user identification, numbering and address information; user security information; user positioning information; user list information.

[0097] PCRF: can control the user and service state QoS service quality, thereby providing differentiated services for users, and providing traffic flow bearing resource guarantee and traffic charging policy for users, such as policy and charging control (PCC) rules.

[0098] SCEF exposes the services and capabilities of 3GPP network functions to third-party applications, and also allows third-party applications to provide information to 3GPP network functions.

[0099] It should be noted that the traditional second generation (2th generation, 2G) or third generation (3th generation, 3G) network adopts circuit switching (Circuit Switched, CS) call technology. With the development of wireless communication technology, the internet protocol multimedia subsystem (IMS) technology based on the Internet Protocol has emerged, gradually replacing the CS call technology. Among them, IMS can be carried on the 4G or 5G network, and provides voice call services based on IP. For the 5GC network, the IMS network is a DN.

[0100] Among them, the IMS network can include a call session control function (CSCF), which is mainly responsible for processing signaling control in the multimedia call session process, such as can be used to manage user authentication of the IMS network, IMS bearer QoS, and other network entities. Control of the Session Initiation Protocol (SIP) session, as well as service negotiation and resource allocation, etc.

[0101] According to the different functions of CSCF, it can be divided into proxy CSCF (P-CSCF), interrogating CSCF (I-CSCF), and serving CSCF (S-CSCF). In essence, they are all SIP servers and can be used to process SIP signaling. Among them, the main functions of P-CSCF include: forwarding the SIP registration request sent by the terminal to I-CSCF; forwarding the SIP message sent by the terminal to S-CSCF, and determining the S-CSCF by the P-CSCF when the terminal initiates the registration process. P-CSCF is the user access node of the IMS network.

[0102] The present application can be applied to an NTN network, and FIG. 3 shows several architecture diagrams of an NTN communication system, which can include at least one non-terrestrial network device and a terminal. For example, the non-terrestrial network device can be a satellite, and the terminal can access the satellite through an air interface and implement communication transmission.

[0103] In the present application, the NTN communication is a deployment scenario of a non-terrestrial network including a satellite system or a high-altitude platform (HAPS), etc., which realizes wireless communication services by means of the wide-area coverage capability of a non-terrestrial network device such as a satellite. The non-terrestrial network device in the present application can also be referred to as an aerial network device, which includes a network device that can be deployed in the air, such as a satellite, a HAPS device, a drone device, etc., without limitation. In the present application, a satellite is taken as an example of an aerial network device for illustration.

[0104] It should be understood that the functions of the access network node such as the (R)AN node described in FIG. 1 or FIG. 2 can be deployed on the non-terrestrial network device. Alternatively, the functions of other nodes such as the functions of part of the core network nodes described in FIG. 1 or FIG. 2, for example, part or all of the functions of network elements such as AMF or SMF can be deployed on the satellite for implementing the corresponding processing. The present application does not limit this.

[0105] It should be noted that in the embodiments of the present application, the device deployed on the non-terrestrial network device for implementing the access function of the communication network is referred to as a non-terrestrial access network device.

[0106] In the present application, the wireless access network device and the terminal can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; can also be deployed on the water surface; can also be deployed on aircraft, drones, balloons and satellites in the air. The application scenarios of the wireless access network device and the terminal device are not limited in the embodiments of the present application.

[0107] As shown in FIG. 3, the communication system can also include a gateway. The gateway can provide communication services for the beam coverage area of the network device such as the satellite. When the base station is deployed on the satellite, the gateway can be used to connect the base station to the core network; when the base station is deployed on the ground, the gateway connects the satellite or the terminal connected by the satellite to the base station. In addition, the gateway can serve as the management, switching and control center of the non-terrestrial communication system, responsible for signal access, user authentication management, service admission control and data exchange of the NTN system, etc.

[0108] In the present application, the NTN communication is a deployment scenario of a non-terrestrial network including a satellite system or a high-altitude platform (HAPS), etc., which realizes wireless communication services by means of the wide-area coverage capability of a non-terrestrial network device such as a satellite. The non-terrestrial network device in the present application can also be referred to as an aerial network device, which includes a network device that can be deployed in the air, such as a satellite, a HAPS device, a drone device, etc., without limitation. In the present application, a satellite is taken as an example of an aerial network device for illustration.

[0109] In addition, according to the working mode of the satellite, the satellite can work in a transparent mode or a regenerative mode, as shown in FIG. 3. When the satellite works in the transparent mode, the satellite can serve as a relay forwarding device to forward signals of other network devices or terminal devices, and can serve as an enhancement processing of ground network coverage. The satellite functions as wireless frequency filtering, frequency conversion and amplification, that is, the satellite mainly serves as a forwarding function to regenerate physical layer signals and does not have functions of other higher protocol layers. As shown in the transparent mode in FIG. 3, the terminal and the base station can perform transparent forwarding through the satellite to realize communication with the core network and the data network. The data network can be an IMS network, for example, the terminal can communicate with a P-CSCF in the IMS network through the satellite.

[0110] In one scenario, when the satellite works in the transparent mode, the satellite can serve as a relay forwarding device for the gateway and the terminal device to forward communication signals between the gateway and the terminal device.

[0111] When the satellite works in the regenerative mode, the satellite has signal processing capability; it can be understood that the satellite has the processing function of the base station and can send signals to other network devices or terminal devices, thereby providing communication services to the terminal device. As shown in the regenerative mode in FIG. 3, the terminal establishes wireless communication with the satellite through the Uu interface to realize communication with the core network and the data network. Similarly, the data network can be an IMS network, for example, the terminal can communicate with a P-CSCF in the IMS network through the satellite.

[0112] In addition, in the scenario of non-terrestrial network communication, the terminal can realize call services through the satellite based on a 2G or 3G network through a CS mode, as shown in the network architecture of the CS call in FIG. 3. The terminal can communicate with a base station subsystem (BSS) and a mobile switching center (MSC) in the 2G or 3G network through the satellite.

[0113] The BSS is responsible for processing communication traffic and signaling between a mobile phone and a network switching subsystem. The BSS can be composed of two basic parts: a base station transceiver connected to the mobile side through a wireless interface and a base station controller connected to the switch side.

[0114] The MSC is an equipment for completing call connection, handover control, wireless channel management and other functions of the mobile network, and is also an interface equipment of the mobile network and the fixed network such as the Public Switched Telephone Network (PSTN) and the Integrated Services Digital Network (ISDN).

[0115] It should be understood that, based on the characteristics of the non-terrestrial network, in NTN communication, the distance between the terminal and the non-terrestrial network equipment such as a satellite is far, and therefore, whether the terminal is in an open area, whether the terminal is blocked, or the placement direction of the terminal may have a greater impact on the communication quality. For example, the elevation angle or the direction angle between the positions of the terminal and the satellite may affect the signal reception quality of the terminal.

[0116] For example, in a scenario of implementing voice call service through satellite communication, a user uses a terminal to make a call, and the calling user can place the terminal in an open area, ensure that the terminal is not blocked, or adjust the placement direction of the terminal to be aligned with the satellite, so as to initiate the voice call service when the satellite signal is strong. However, for a scenario of using a terminal to receive a call, the network usually needs to page the terminal first, but if the terminal of the called user currently has poor satellite signal quality and cannot receive the paging message, or the terminal cannot respond to the paging message, paging failure may occur, and the call cannot be connected. Therefore, for a non-terrestrial network communication scenario, the terminal of the called user may cause the problem of paging failure and call connection failure due to poor signal quality.

[0117] It should be noted that the functions of other network elements included in FIGS. 1 to 3 can be referred to the related description in the conventional technology, which will not be described herein. The network architecture shown in FIGS. 1 to 3 is only used for example, and is not used to limit the technical solutions of the present application. Those skilled in the art should understand that other network elements or devices can be included in the specific implementation process, and the number of access network devices, terminal devices and / or core network devices can also be determined according to specific needs.

[0118] Optionally, each network element shown in FIGS. 1 to 3 can be a device, or a functional module in the device, or a logical functional unit. It can be understood that the above functions can be network elements in a hardware device, such as a communication chip in a mobile phone, or a software function running on a special hardware, or a virtualized function instantiated on a platform (for example, a cloud platform).

[0119] It can be understood that the devices or network elements in the communication system of FIGS. 1 to 3 can directly communicate with each other, or can communicate through forwarding of other devices, and the embodiments of the present application do not make specific limitations thereto.

[0120] It can be understood that the above-mentioned FIG. 1 to FIG. 3 are only schematic diagrams, and do not constitute a limitation on the applicable scenarios of the technical solutions provided in the present application. It should be understood by those skilled in the art that, in the specific implementation process, the communication system can include fewer devices or network elements than those shown in FIG. 1 to FIG. 3, or the communication system can also include other devices or other network elements, and the number of devices or network elements in the communication system can also be determined according to specific needs.

[0121] For example, each network element in FIG. 1 to FIG. 3 can be implemented by a communication device 400 in FIG. 4. FIG. 4 shows a schematic diagram of the hardware structure of the communication device applicable to the embodiments of the present application. The communication device 400 includes at least one processor 401, a communication line 402 and at least one communication interface 404. Optionally, the communication device 400 can also include a memory 403.

[0122] The processor 401 can be one or more central processing units (CPU). In the case of a CPU, the CPU can be a single core CPU or a multi-core CPU. The processor can be a general purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, and can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution or executed by a combination of hardware and software modules in the processor.

[0123] Optionally, the processor can include one or a combination of central processing units (CPU), application-specific integrated circuits (ASIC), digital signal processors (DSP), microprocessor units (MPU), microcontroller units (MCU), graphics processing units (GPU), field programmable gate arrays (FPGA), artificial intelligence processors (AI processor) or neural network processors (Neural Processing Unit, NPU).

[0124] The communication line 402 can include a path for transmitting information between the above-mentioned components, such as a bus.

[0125] The communication interface 404 is configured to communicate with other devices or communication networks using any transceiver-like mechanism, such as an Ethernet interface, a RAN interface, a wireless local area networks (WLAN) interface, and the like.

[0126] The memory 403 can include, but is not limited to, a cache, a Read-Only Memory (ROM), a Random Access Memory (RAM), a synchronous dynamic random access memory (SDRAM), a hard disk drive (HDD), or a solid-state drive (SSD), an erasable programmable ROM (EPROM), or a Compact Disc Read-Only Memory (CD-ROM), and the like. The memory is any medium capable of carrying or storing desired program codes in the form of instructions or data structures and capable of being accessed by a computer, but is not limited thereto. The memory in the embodiments of the present application can also be a circuit or any other device capable of realizing a storage function, used for storing computer programs or instructions, and / or data. Alternatively, the memory can exist independently and be connected to the processor through the communication line 402. Alternatively, the memory can also be integrated with the processor. The memory provided in the embodiments of the present application can generally have a non-volatility. The memory 403 is configured to store computer execution instructions related to the schemes of the present application and to be controlled to execute by the processor 401. The processor 401 is configured to execute the computer execution instructions stored in the memory 403, so as to realize the method provided in the embodiments of the present application.

[0127] Optionally, the computer execution instructions in the embodiments of the present application can also be referred to as application program codes, which are not specifically limited in the embodiments of the present application.

[0128] In a specific implementation, as an embodiment, the processor 401 can include one or more CPUs, such as CPU0 and CPU1 in FIG. 4.

[0129] In a particular implementation, as one example, the communication apparatus 400 can include multiple processors, such as the processor 401 and the processor 407 in FIG. 4. Each of these processors can be a single-CPU processor or a multi-CPU processor. A processor here can refer to one or more devices, circuits, and / or processing cores for processing data, such as computer program instructions.

[0130] In a particular implementation, as one example, the communication apparatus 400 can also include an output device 405 and an input device 406. The output device 405 is in communication with the processor 401 and can display information in various ways. For example, the output device 405 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, a projector, or the like. The input device 406 is in communication with the processor 401 and can receive user input in various ways. For example, the input device 406 can be a mouse, a keyboard, a touch screen device, a sensor device, or the like.

[0131] The communication apparatus 400 described above can be a general-purpose device or a special-purpose device. In a particular implementation, the communication apparatus 400 can be a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal apparatus, an embedded device, or a device having a similar structure as that in FIG. 4. The embodiments of the present application do not limit the type of the communication apparatus 400.

[0132] The communication method provided by the embodiments of the present application is described below in detail.

[0133] It should be noted that the names of messages between the network elements in the embodiments of the present application or the names of parameters in the messages are only examples, and other names can also be used in a particular implementation. The embodiments of the present application do not limit the names.

[0134] It can be understood that some or all of the steps in the embodiments of the present application are only examples, and other steps or variations of various steps can also be performed. In addition, the steps can be performed in different orders according to the embodiments of the present application, and it is possible that not all of the steps in the embodiments of the present application are performed.

[0135] Based on the above technical problems, the embodiment of the present application provides a communication method, which is applied to a non-terrestrial communication network. A network device can send a specific type of message to a terminal. The message can be used to call the terminal through a non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network. Therefore, the terminal can be reminded to solve the problem that the receiver of the communication service misses the communication service due to poor signal quality in the non-terrestrial network, improve the communication efficiency, and improve the user experience.

[0136] As shown in FIG. 5, the present application provides a communication method, which can include the following steps.

[0137] 501: The network device sends a first message, which is used to call the terminal through a non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network. Correspondingly, the terminal receives the first message.

[0138] The terminal communicates through a non-terrestrial network. That is, the terminal can access the network through a non-terrestrial network device and communicate with a data network through a core network. As shown in FIG. 3, the terminal is in a satellite network, and the terminal can access the core network through a satellite and communicate with an IMS network through the core network to realize voice call service.

[0139] In an implementation manner, the first message can be an alert message (Alert) or a notification message, which is used to notify the terminal that there is a communication service through the non-terrestrial network. For example, when the non-terrestrial network accessed by the terminal is poor, such as the signal strength is lower than a preset threshold and / or the signal quality is lower than a preset threshold, the terminal cannot receive a regular paging message, but can receive the first message. Therefore, the network device can send the first message to notify the terminal that there is a communication service at present. Alternatively, the first message can be an enhanced form of the existing paging message. When the non-terrestrial network of the terminal is poor, the network cannot page the terminal through the existing paging, and can send the first message through a specific channel (or a dedicated channel) in an enhanced manner to call the terminal through the non-terrestrial network.

[0140] For example, if the network device obtains that there is a communication service for the terminal at present, and the terminal is in an idle state or an inactive state, the network device can send the first message to call the terminal through the non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network.

[0141] The terminal in the idle state (e.g., represented as idle) means that there is no radio resource control (RRC) connection between the terminal and the RAN node, and there is no non-access stratum (NAS) connection between the terminal and the core network, i.e., there is no signaling connection between the terminal and the RAN node and the core network, and the RRC state and the connection management (CM) state of the terminal are both in the idle state. For example, the idle state (idle) can include RRC-idle and CM-idle.

[0142] In addition, the terminal in the inactive state (e.g., RRC inactive state) means that the RRC connection between the terminal and the RAN node is in a suspended state, and the CM state between the terminal and the core network is in a connected state (Connected), i.e., CM-Connected state.

[0143] The communication service can be a voice call service or a data service, such as making a phone call, a voice service, a video service, a short message service, a notification message of an application program, etc.

[0144] In an implementation manner, the network device can be a RAN node, or the network device can be a network element of the core network, such as an AMF or other network element.

[0145] In an implementation manner, the network device can broadcast the first message. The first message can include an identifier corresponding to the terminal, which is used to indicate the terminal with the communication service. Thus, one or more terminals receiving the first message can obtain the terminal identifier carried in the first message, and determine whether the first message is paging itself by comparing the terminal identifier with the terminal identifier of itself.

[0146] It should be understood that in the field of communication technology, in order to identify different terminals, the corresponding terminal identifier can be carried in the message of interaction, for example, the network can allocate a temporary mobile subscriber identity (TMSI) or a globally unique temporary UE identifier (GUTI) to the terminal.

[0147] Different message types can carry different types or lengths of terminal identifiers. For example, a paging message (paging) in a 5G network for paging a terminal can carry a short-term temporary mobile subscriber identity (S-TMSI). The length of the S-TMSI can be 48 bits.

[0148] In an implementation, the first message can include a first identifier corresponding to the terminal, and the length of the first identifier is less than a first value, which is the length of the identifier of the terminal carried in the paging message for paging the terminal. That is, the terminal identifier carried in the first message can be different from the terminal identifier carried in the existing paging message (paging), and the terminal identifier carried in the first message is specifically the first identifier, and the length of the first identifier can be less than the length of the terminal identifier carried in the paging message (paging). For example, the length of the terminal identifier carried in the paging message (paging) is the first value, and the length of the first identifier can be less than the first value. For example, the first value can be 48 bits or other possible values.

[0149] In an optional implementation, the first message is an Alert message, and a service for paging a terminal by sending the Alert message can be referred to as an Alert service. An operator can assign a dedicated identifier corresponding to the Alert service, such as the first identifier, to a user of the Alert service. For example, if the number of users of the Alert service of an operator is less than or equal to 1024, the operator can assign a first identifier to a user of the Alert service, and the length of the first identifier can be less than or equal to 10 bits.

[0150] In another implementation, the first identifier can be obtained by compressing an existing terminal identifier. For example, the first identifier can be generated by processing an S-TMSI by using a compression algorithm, and the length of the first identifier is less than the length of the S-TMSI.

[0151] To implement compression of the UE identifier, in a process of network registration of a terminal, a core network (such as an AMF) can assign a first identifier corresponding to an Alert service to the UE, that is, an identifier used by the UE when monitoring an Alert message. When the UE monitors the Alert message (for example, by using a dedicated channel corresponding to the Alert message), the UE determines whether the network is paging itself by using the first identifier carried in the Alert message sent by a base station. If the first identifier carried in the Alert message is the same as the identifier assigned to the UE by the network, the UE determines that the network is paging itself. Otherwise, if the first identifier carried in the Alert message is different from the identifier assigned to the UE by the network, the UE determines that the Alert message is not for paging itself.

[0152] In an embodiment, the network device sends the first message, specifically, the network device can send the first message according to a configured policy, for example, the network device can send the first message according to a first policy. The first policy can include at least one of the following: calling the terminal through the first message under the non-terrestrial network, or calling the terminal through the first message after calling the terminal through the paging message fails (for example, after sending a certain number of paging messages, no response from the terminal is received) under the non-terrestrial network, or calling the terminal through the first message after calling the terminal through the paging message fails under the non-terrestrial network, at this time the paging message is no longer sent, or calling the terminal through the first message and the paging message alternately under the non-terrestrial network. For example, the first policy can include alternately sending the paging message and the first message a certain number of times, for example, the network device sends a paging message once, then sends a first message once, and repeats in this manner; or the network device sends two paging messages, then sends a first message, and repeats in this manner.

[0153] For example, the network device can be a mobility management device, such as an AMF, and for a terminal accessing a non-terrestrial network, the pre-configured policy on the AMF side can be that the AMF sends an alert message such as a first message to the RAN node; or the AMF sends a paging message to the RAN node, which carries indication information for sending an alert message or carries a first policy, the indication information or the first policy can be used to instruct the RAN node to call the terminal by sending an alert message to the terminal, or to call the terminal by sending an alert message to the terminal after the paging fails; or the AMF can alternately send the paging and the alert message to the RAN node, and the RAN sends the paging to the UE based on the paging message sent by the AMF, or the RAN sends the alert message to the UE based on the alert message sent by the AMF.

[0154] For example, the network device is a RAN node, and the RAN node can send a paging message or an Alert message to the terminal based on a local policy, or alternately send the paging and the Alert message to the RAN node, or send the Alert message after the paging fails. Optionally, the RAN node can send the paging message to the terminal according to the received indication information or the first policy, and send the Alert message after the paging fails.

[0155] Correspondingly, the terminal receives the first message. As described above, the terminal can determine whether the first message is used to page itself according to the terminal identifier carried in the first message, for example, if the terminal identifier carried in the first message does not match the identifier of the terminal itself, the first message is discarded; if the terminal identifier carried in the first message matches the identifier of the terminal itself, the following steps are performed.

[0156] 502: In response to the first message, the terminal sends a second message to the network device for establishing a communication connection with the non-terrestrial network when the signal of the non-terrestrial network satisfies the first condition. Correspondingly, the network device receives the second message.

[0157] The first condition includes at least one of the following: the signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or the signal quality of the non-terrestrial network is greater than or equal to a second threshold value. For example, the signal strength of the non-terrestrial network can be represented by a reference signal receiving power (RSRP), and the first threshold value can be a pre-configured threshold value corresponding to the RSRP. The signal quality of the non-terrestrial network can be represented by a reference signal receiving quality (RSRQ), and the second threshold value can be a pre-configured threshold value corresponding to the RSRQ.

[0158] That is, when the signal of the non-terrestrial network of the terminal changes to the above-mentioned better state, the terminal can respond to the first message and send the second message to the network device to establish a communication connection with the non-terrestrial network, thereby realizing the requested communication service or obtaining relevant information of the requested communication service, such as service type, caller information, and communication service initiation time information.

[0159] In an embodiment, the first condition can further include that the terminal switches from a first state to a second state, wherein the first state corresponds to a terminal state of monitoring the alert message, that is, the terminal in the first state starts to monitor the alert message such as the first message. The second state corresponds to a terminal state of monitoring a paging message, that is, the terminal in the second state starts to monitor the existing paging message paging. Therefore, the above-mentioned first condition means that the current signal of the non-terrestrial network of the terminal is adjusted to be better, and the terminal can be paged by using the existing network device to send the paging message paging. When the terminal switches from monitoring the alert message to monitoring the paging message, the execution of the step of sending the second message can be triggered. At this time, the signal of the non-terrestrial network of the terminal is better, and the terminal can trigger the execution of the step of sending the second message through the non-terrestrial network.

[0160] It should be understood that the terminal state in the present application, such as the first state or the second state, can be determined or switched according to the signal strength or signal quality of the terminal's current non-terrestrial network, i.e., when the signal of the non-terrestrial network on the terminal side is good, such as satisfying the first condition, the terminal is switched to the second state, and the terminal in the second state can start monitoring the paging message. Conversely, when the signal of the non-terrestrial network on the terminal side is poor, such as not satisfying the first condition, the terminal is switched to the first state, and the terminal in the first state can start monitoring the alert message, i.e., the first message.

[0161] It should be understood that in the embodiments of the present application, the first message is used to call the terminal under the non-terrestrial network of the network, and informs the terminal that there is a communication service. In the case that the non-terrestrial network of the terminal is poor and the terminal cannot receive the paging but can receive the first message (such as the Alert message), the terminal still cannot send the uplink signaling to the network device. That is, the user needs to adjust the non-terrestrial network receiving scenario of the terminal according to the first message, such as performing a mobile-to-satellite operation, so that when the non-terrestrial network of the terminal satisfies the first condition, the terminal can send the response message of the first message, such as the second message, to the network device.

[0162] The second condition can include at least one of the following: the signal strength of the non-terrestrial network is less than a first threshold; and the signal quality of the non-terrestrial network is less than a second threshold.

[0163] Optionally, the second condition can further include that the terminal switches from the second state to the first state, the second state corresponds to monitoring the paging message, and the first state corresponds to monitoring the alert message.

[0164] In an embodiment, if the terminal is in an idle state or an inactive state, and it is determined that the signal receiving index of the non-terrestrial network satisfies the second condition, the terminal can start detecting the first message or monitoring the first message.

[0165] In an embodiment, in response to the first message, the terminal rings and displays a notification, the ringing and / or the notification are used to indicate that there is a communication service for the terminal, and the notification is also used to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal.

[0166] It should be understood that in combination with the characteristics of the aforementioned non-terrestrial network, the "adjusting the non-terrestrial network signal receiving scenario of the terminal" in the embodiments of the present application refers to the corresponding operation of the user adjusting or improving the non-terrestrial network receiving state of the terminal, which can include at least one of the following operations: taking the terminal out of the backpack, moving the terminal to an open area, aligning the terminal to the outside of the window or door, aligning the terminal to the satellite or high-altitude platform device, adjusting the placement angle or direction of the terminal, and the like. Alternatively, the "adjusting the non-terrestrial network signal receiving scenario of the terminal" in the embodiments of the present application can also be described as "performing a satellite operation on the terminal", such as performing a satellite operation on a mobile phone. Correspondingly, as the user performs a satellite operation on the terminal, the signal quality or strength of the non-terrestrial network of the terminal improves and meets the preset condition, and the terminal is successfully aligned to the satellite. This will not be repeated later.

[0167] That is, when the terminal detects the first message matching the identity of itself, it can automatically respond to the first message to ring, such as playing a prompt tone or a loud sound on the terminal, to remind the user to check the terminal. Alternatively, the display interface of the terminal can also pop up a prompt message or a notification message to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal. For example, the terminal is a mobile phone, the notification can include information such as "please take the mobile phone outside or to a place with better signal", "please align the mobile phone to the outside of the window", "please adjust the placement direction of the mobile phone according to the diagram", and the like, so that the user can adjust the non-terrestrial network signal receiving scenario of the terminal according to the notification, so that the terminal is unobstructed, the terminal is in an open area, or the direction angle or the pitch angle between the terminal and the satellite meets the preset condition, so that the signal of the non-terrestrial network becomes better.

[0168] In the first embodiment, the warning message in the embodiments of the present application can be used by the network device to remind the user that there is a communication service and to support establishing a session corresponding to the communication service, for example, to support connecting a voice call service. For example, the calling party is terminal 1 calling the called party terminal 2, the signal of the non-terrestrial network on the terminal 2 side is poor, the network device sends a warning message such as a first message, and after the terminal 2 receives the first message, the user can adjust the non-terrestrial network signal receiving scenario of the terminal, so that the signal of the non-terrestrial network becomes better, thereby sending a second message to the network device for successfully establishing a session corresponding to the communication service.

[0169] In this embodiment, the second message can be a service request message for requesting to establish a session corresponding to the communication service. The network device receives the second message and performs other steps of session establishment. The specific interaction process will be introduced later in combination with the drawings and embodiments, which will not be repeated here.

[0170] In addition, for the first mode, the network device and the terminal can also be configured with a first time length, which is used to indicate the maximum time length between the terminal receiving the first message and sending the second message. That is, after the terminal receives the first message, the user can be reminded to adjust the signal receiving scenario of the terminal within the first time length, so that the terminal successfully sends the service request message to the network device for requesting to establish a session. After the network device side sends the first message, the first time length can be used as the maximum time length for the network to wait for the terminal response. After the first time length expires or times out, the network determines that the called terminal of the communication service does not respond to the communication service. For example, for a voice call service, the network can generate a missed call reminder message and subsequently send it to the called terminal.

[0171] The network device or the terminal can agree on or pre-configure possible values of the first time length through a protocol, or the network device can send indication information corresponding to the first time length to the terminal. For example, when the network device indicates to the terminal to activate the alert message (the first message), the indication information of the first time length can be carried. This will be described in detail later, and will not be described here.

[0172] In the second implementation, the alert message in the embodiments of the present application can be used by the network device to remind the user that there is a communication service, but the network device does not support establishing a session corresponding to the communication service. The user can respond, such as redialing, by obtaining the telephone number information of the calling party. For example, for a voice call service, the calling terminal 1 calls the called terminal 2, and the signal of the non-terrestrial network on the terminal 2 side is poor. The network device sends an alert message, such as the first message. After the terminal 2 receives the first message, the user can adjust the non-terrestrial network signal receiving scenario of the terminal, so that the signal of the non-terrestrial network becomes better, and the terminal sends a second message to the network device for registering the terminal to the network. Thus, the network device determines that the terminal successfully accesses the non-terrestrial network, and can send related information of the communication service that has not been responded to, such as the service type, the telephone number information of the calling party, the time information of the initiation of the communication service, and the like, to the terminal.

[0173] For example, for a voice call service, in the implementation mode in which the network device starts to page or notify the terminal of the alert message, the network determines that the current voice call does not need to be connected, and the core network can notify the IMS network to terminate the call, and the IMS network notifies the calling party to hang up the phone. Specifically, if the network side starts to send the alert message by the RAN node, the RAN node can notify the core network to terminate the call, and the core network can notify the IMS network to terminate the call.

[0174] In this implementation, the second message can be a registration request message, which is used to register the terminal to the network, and the network device receives the second message and performs registration for the terminal. Thus, other network elements of the core network learn that the terminal has been successfully registered to the network, and can send the information of the initiator of the aforementioned non-responded communication service to the terminal, so that the terminal can obtain the information of the initiator. The specific interaction process will be described in combination with the drawings and embodiments, and will not be described here.

[0175] The above embodiments of the present application can be used in the scenario of non-terrestrial network communication. The network can send a specific type of message, such as an alert message or other forms, to the terminal. The message can be used to call the terminal through the non-terrestrial network or notify the terminal that there is a communication service through the non-terrestrial network. Thus, the terminal can be reminded to solve the situation that the receiver of the communication service in the non-terrestrial network misses the communication service due to poor signal quality, improve the communication efficiency, and improve the user experience.

[0176] Based on the above solution, the present application provides several different implementation methods, as shown in FIG. 6. According to whether the first message carries the initiator information of the current communication service, the solution can be divided into two categories, including: the first message carries the initiator information (such as the information of the calling party) of the current communication service; or the first message does not carry the initiator information (such as the information of the calling party) of the current communication service, and the terminal can obtain the initiator information of the unresponsive communication service through other methods. Based on this, according to whether the terminal supports successfully establishing the session corresponding to the current communication service in response to the first message, the solution can also be divided into two categories, such as the aforementioned method one and method two. The method one corresponds to supporting establishing the session corresponding to the communication service, such as for the voice call service, the first message supports connecting the phone. If the non-terrestrial network of the terminal meets the first condition within the first time period, the terminal sends a service request message to the network device, and the phone is connected. If the first condition is met after the first time period expires, the terminal sends a registration request message to the network device, and the terminal can obtain the calling party information through a short message or a NAS message. The method two corresponds to not supporting establishing the session corresponding to the communication service, the first message does not support connecting the phone, and the first message is only used to remind the user to respond. When the non-terrestrial network of the terminal meets the first condition, the terminal can obtain the unresponsive communication service, send a registration request message to the network device, and obtain the initiator information to respond, such as redialing the phone. For the first message carrying the information of the calling party, such as the first message supporting connecting the phone, if the non-terrestrial network of the terminal meets the first condition within the first time period, the terminal sends a service request message, and the phone is connected. If the first time period expires, the terminal displays the missed call, and the subsequent redialing of the phone can be based on the information of the calling party. If the first message does not support connecting the phone, the terminal displays the missed call and the information of the calling party. The interaction process corresponding to the different implementation methods will be introduced in combination with the specific embodiments.

[0177] In an implementation manner, the first message can further include indication information corresponding to the initiator of the communication service, which is used to indicate whether the initiator belongs to the pre-configured user, or indicate the second identifier corresponding to the initiator, and the second identifier is the phone number information.

[0178] The pre-configured user refers to that, for the first message provided by the embodiments of the present application, the operator can prompt the user to pre-configure the associated user as the pre-configured user. For example, for the voice call service, the user can set the family members or the white list users, that is, the users in the family members or the white list users are used as the calling party of the communication service, and then the network device supports paging or notifying the user through the first message; otherwise, if the user other than the pre-configured user, such as the non-white list user, is used as the calling party of the communication service, the network device does not support paging or notifying the user through the first message.

[0179] In one embodiment, the sending of the first message can be used to indicate that the communication service is triggered by a pre-configured user, that is, the alert service can only be triggered by a pre-configured user, such as a communication service initiated by any user in the white list can trigger the calling of the user through the first message (Alert). In this embodiment, the network device sends the first message, and the first message can not include the information of the initiator of the communication service, because the first message is triggered by the communication service initiated by the pre-configured user, so that the terminal receiving the first message can determine that there is currently a call initiated by a pre-configured user, but does not know which specific user among the pre-configured users, and the network device can subsequently send the information of the calling party, such as the phone number information, to the terminal through a short message or other means.

[0180] In another embodiment, the network device can carry the indication information corresponding to the initiator of the communication service, such as the phone number information of the initiator, through the first message, so that the terminal receiving the first message can also obtain the indication information corresponding to the initiator carried in the first message.

[0181] For example, the indication information included in the first message can be used to indicate that the calling party of the current voice call service is a user in the family members or the white list users, and the user is supported to be paged through the first message; otherwise, the indication information included in the first message can be used to indicate that the calling party of the current voice call service is not a user in the family members or the white list users, and the user is not supported to be paged through the first message.

[0182] Further, for the above-mentioned embodiment one, the terminal can determine whether to successfully establish the communication service according to the indication information corresponding to the initiator carried in the first message, taking the voice call service as an example, the user can determine whether to answer the voice call according to the indication information of the initiator.

[0183] For the above-mentioned embodiment two, the terminal can obtain the information of the initiator of the communication service that does not respond according to the indication information corresponding to the initiator carried in the first message, so that subsequent response can be selected. Taking the voice call service as an example, the user can subsequently call back the user or reply a short message according to the indication information of the initiator.

[0184] In another embodiment, the network device can send the terminal information of the initiator of the communication service, such as telephone number information. Optionally, the network device can further send a third message to the terminal, the third message being used to indicate the unresponsive communication service, and the third message including the second identifier corresponding to the initiator of the communication service, the second identifier being the telephone number information. That is, when the first message does not carry the indication information corresponding to the initiator of the communication service, the network device can further send the telephone number information corresponding to the initiator to the terminal through the third message, so that the terminal can determine the information of the initiator of the unresponsive communication service according to the telephone number information, and can subsequently select other ways to respond. Taking the communication service as a voice call service as an example, the user can subsequently call back the user or reply a short message according to the indication information of the initiator.

[0185] In addition, it should be understood that, in the scenario of non-terrestrial networks, the network can use the paging or notification manner of sending the first message to notify the terminal of the existence of the communication service through pre-configuration or protocol agreement.

[0186] Alternatively, in another embodiment, the network device can send a fourth message to the terminal before sending the first message, the fourth message being used to indicate that the terminal can detect or monitor the first message. Optionally, the fourth message can include an activation indication used to activate the function of the alert message. That is, the terminal side monitors the function of the alert message, and the network device needs to send an activation indication to the corresponding terminal, so that the terminal can enable the function. Otherwise, the terminal does not have the function of monitoring the alert message, or the function of monitoring the alert message of the terminal is not available.

[0187] In this embodiment, when the terminal receives the fourth message and determines that the current non-terrestrial network satisfies the second condition, the terminal can start monitoring the first message. If the terminal does not receive the fourth message, the terminal will not start monitoring the first message.

[0188] In an embodiment, the fourth message can include a first time length or carry indication information of the first time length. The first time length is used to indicate the maximum time length between the reception of the first message by the terminal and the sending of the second message by the terminal. Alternatively, the first time length is used to indicate the maximum time length for the network to wait for the terminal to respond to the first message.

[0189] In an embodiment, after receiving the first message, the terminal can start a first timer corresponding to the first time length, and the first timer is used to remind the user to adjust the non-terrestrial network signal receiving scenario of the terminal, so that the terminal can successfully respond to the first message and send the second message, so that the terminal can successfully establish the session. The time length of the first timer can be the first time length, and the first timer is used to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal before the first timer expires. In combination with the foregoing example, the terminal can pop up a prompt information on the display interface to remind the user, such as “Please point the phone to the window outside within one minute”, “Please take the phone to an open area within 50 seconds”, and optionally, the terminal interface can also display countdown information and the like.

[0190] In an embodiment, after receiving the first message, the terminal can send the second message to the network device in response to the first message before the first timer expires and when the signal of the non-terrestrial network meets the first condition, where the second message is a service request message. That is, the terminal can send the service request message to the network device within the first time length, so that the session corresponding to the current communication service can be successfully established.

[0191] In an embodiment, after receiving the first message, the terminal can send the second message to the network device in response to the first message when or after the first timer expires and when the signal of the non-terrestrial network meets the first condition, where the second message is a registration request message. That is, the terminal can send the registration request message to the network device after the first time length expires or expires, so that the terminal can be successfully registered to the network, and thus can receive the information of the initiator of the communication service which has not been responded before.

[0192] In an embodiment, before the network device activates the function of the warning message by sending the fourth message to the terminal, the terminal can first report to the network device that the terminal can support detecting or monitoring the warning message. That is, the method can further include the following step: the terminal sends a fifth message to the network device, and the fifth message is used to indicate that the terminal has the capability of detecting the first message.

[0193] According to the foregoing, it can be known that the communication service in the embodiments of the present application can include voice call or data service. For the voice call service, after the terminal sends the second message to the network device, the terminal can receive a downlink data packet from the network, and the downlink data packet can carry a SIP message for requesting a voice call. The terminal can send a response message corresponding to the SIP message and perform other steps of call establishment, so that the voice call can be connected. For the data service, after the terminal sends the second message to the network device, the terminal can receive a downlink data packet from the network, and the downlink data packet can carry the downlink data corresponding to the terminal.

[0194] In another embodiment, the network element of the core network can obtain the indication information corresponding to the initiator from the IMS network. Optionally, the communication method can further include the following steps: the network device receives a sixth message, the sixth message includes the indication information corresponding to the initiator of the communication service, and the indication information indicates whether the initiator belongs to the pre-configured user or indicates the second identifier corresponding to the initiator, the second identifier being the telephone number information.

[0195] For example, the IMS network element receives a voice call request (SIP invite) message of a caller, the SIP invite message is used to initiate a call request to the terminal, and the SIP invite message can carry the indication information corresponding to the caller. Then, the IMS network element can send the SIP invite message to the network element of the core network, such as the UPF, which corresponds to the sixth message described above. Subsequently, the UPF can send a downlink data notification message of the terminal to the SMF, which can carry the indication information corresponding to the caller; the SMF sends an N1N2 message to the AMF, which can carry the indication information corresponding to the caller. Therefore, when the AMF sends the first message to the RAN node, the indication information corresponding to the initiator of the current communication service can be carried or not carried according to the pre-configured sending alert message strategy.

[0196] In an embodiment, for the method of carrying the caller's information (such as telephone number information) in the Alert message, considering the limited air interface resources, it is necessary to compress the UE identifier and the caller's information to save the signaling overhead. In the paging sent by the network to the UE, the UE identifier carried can be S-TMSI. In order to realize the compression of the UE identifier, the core network (such as AMF) allocates an identifier corresponding to the Alert service to the UE in the process of registering the network, that is, the identifier used by the UE when monitoring the Alert message.

[0197] It should be noted that if the core network allocates an identifier corresponding to the Alert service to the UE in the process of registering the network, it can be understood that the network activates the Alert service for the UE, and at this time the network can no longer send the Alert activation indication to the UE, such as not sending the fourth message in the foregoing embodiment. In addition, if the network sends the identifier corresponding to the Alert service to the UE, the GUTI of the terminal can also be included in the registration acceptance message, that is, the terminal uses the identifier corresponding to the Alert service when monitoring the Alert message, and uses the S-TMSI included in the GUTI when monitoring the paging message.

[0198] In an embodiment, the core network obtains the caller's information from the IMS and sends the process of sending the Alert message to the UE can include the following process:

[0199] (1) IMS network element such as P-CSCF receives the information of the calling party from the SIP invite message, which can be obtained from the "from" header field in the invite message or "P-Asserted-Identity".

[0200] (2) P-CSCF sends the calling number to PCF, which can be sent to PCF through the authentication authorization request (AAR) carrying the information of the calling party, or P-CSCF calls the service provided by PCF to send the information of the calling party to PCF.

[0201] (3) PCF sends the information of the calling party to other network elements of the core network, such as through PCC policy message to SMF.

[0202] (4) SMF further sends the information of the calling party to AMF through the N1N2 message provided by AMF service.

[0203] (5) AMF further sends the information of the calling party to the RAN node through the paging / Alert message.

[0204] (6) The RAN node carries the identity of the called UE and the calling RAN node in the Alert message, wherein the identity of the called UE is mainly used to identify the Alert message sent by the network, which can make the UE receiving the Alert message determine whether to call itself. The information of the calling party is used to determine the calling party of the communication service.

[0205] Considering the limited air transmission resources, the Alert message sent by the RAN node needs to be compressed as much as possible to save the air resources, so the signaling length carried by the Alert message can be compressed. The indication information of the calling party is carried in the Alert message, and the UE can determine the initiator of the communication service through the indication information. The specific implementation manner is as follows:

[0206] (1) In the cellular network, the UE can subscribe to the Alert service to the core network. And the UE can determine whether to receive the Alert when the UE is located in the satellite network through the pre-configuration of the user negotiated with the network. For example, the core network and the UE negotiate the white list, and only when the calling phone calls the UE on the white list, the AMF will send the Alert message, or the AMF can inform the UE whether the communication service is initiated by the user on the white list. Optionally, the core network can also allocate the UE identity corresponding to the Alert service to the UE, which does not reuse the current S-TMSI (48 bits), for example, if the total number of users of the operator's Alert service does not exceed 1024, the UE identity can be compressed to 10 bits.

[0207] (2) When the network receives that the UE has new communication service, the indication information of the calling party received by the AMF can be an index (index) of a user in the pre-configured user list, or can be calling number information, which can be filtered by the AMF.

[0208] (3) When the network sends the Alert message to the UE, the Alert message can include the identity of the UE and the indication information of the calling party. Among them, the UE identity included in the Alert message can be the UE identity corresponding to the Alert service allocated by the core network for the UE. The indication information of the calling party included in the Alert message can be the index (index) corresponding to the user in the pre-configured user list.

[0209] For example, the user list pre-configured by the UE is the family members, including 7 calling numbers, which can be indicated by 3 bits, such as 000 indicating that the calling party is not on the pre-configured list. In addition to 000, 001-111 can be used to indicate the 7 pre-configured calling numbers respectively. For another example, the UE is pre-configured with a white list user, and the information of the white list user includes 8 calling numbers, which can be indicated by 3 bits, and 000-111 can be used to indicate the 8 calling numbers in the white list user respectively.

[0210] Optionally, the indication information of the calling party can be carried in the reserved bits of the Alert message, or in part of the UE identity field of the Alert message.

[0211] The following describes several possible specific embodiments. Among them, the following embodiments of the present application only take the first message as an example of the alert message Alert, and take the current communication service of the terminal as the voice call service, which does not limit the application of the present application.

[0212] Embodiment one, the first message does not carry the information of the communication service initiator, and the response to the first message supports the establishment of the session corresponding to the communication service.

[0213] As shown in FIG. 7, the method can include the following steps.

[0214] 701: The UE sends a registration request message to the AMF, including the capability of the terminal to receive the alert message. Correspondingly, the AMF receives the registration request message.

[0215] Among them, the registration request message can include the capability of the terminal to receive or monitor the alert Alert message.

[0216] The above registration request message can correspond to the fifth message in the foregoing embodiments.

[0217] 702: The AMF sends a registration accept message to the UE, including indication information of activating the alert message.

[0218] The AMF determines to activate the Alert function of the UE, that is, the UE will be called by sending an Alert message to the UE in the future, and the indication information of activating the Alert can be included in the registration accept message sent by the AMF to the UE, which is used to indicate that the network will notify the UE by sending an Alert message to the UE in the future.

[0219] Optionally, the AMF determines to activate the Alert mechanism of a certain terminal, which can be determined based on the policy of the AMF. Specifically, the AMF can determine to activate the Alert mechanism of the terminal based on at least one of the following: the terminal reports in the foregoing step 701 that it has the monitoring capability of the Alert, the terminal subscribes to the Alert service of the network, there is a RAN in the registration area of the terminal that supports sending an Alert message, and the load status of the network performing paging, etc.

[0220] Wherein, whether the terminal subscribes to the Alert service of the network, the AMF can determine by querying the subscription information of the UE from the UDM, that is, after the UE subscribes to the Alert service, the subscription information of the UE saved in the UDM includes the Alert service, and the AMF can query the subscription information of the UE from the UDM during the process of the UE registering the network to determine whether the UE subscribes to the Alert service.

[0221] In addition, the user terminal can subscribe to the Alert service in a separate subscription manner, or can subscribe to the Alert service by default when subscribing to the NTN service (such as satellite communication service) of the terminal, which can be determined according to the subscription policy of the operator.

[0222] Optionally, the registration accept message can also include a first time length, that is, an Alert response time length, which is used to indicate that the terminal needs to send a response message to the network within the first time length after receiving the Alert message. If the terminal sends a response message to the network within the first time length, the call can be connected, and if the terminal cannot send a response message to the network within the first time length, the call can be terminated.

[0223] 703: The UE establishes an IMS PDU session.

[0224] After the UE completes the network registration, the UE can send a PDU session establishment request message to the SMF through the AMF, the PDU session establishment request message including a data network name (DNN) of IMS, that is, the PDU session is used to carry IMS communication related signaling and data. After the SMF receives the PDU session establishment request message, the SMF sends a PDU session establishment accept message to the UE.

[0225] In the IMS PDU session establishment process, the UE can also obtain the address of the P-CSCF in the IMS network, for subsequent IMS communication of the UE.

[0226] 704: The UE performs IMS registration.

[0227] Specifically, the UE can send a SIP registration message to an IMS network element (such as a P-CSCF) through the established IMS PDU session, to perform an IMS registration process, or to request registration to the IMS network, or to request registration in the IMS network.

[0228] If the UE is successfully registered in the IMS network, the UE can receive a SIP registration success message (such as a SIP registration ok, or 200OK) from the IMS network element (such as the P-CSCF). Through this step, the UE is registered in the IMS network, and can subsequently perform related call services through the IMS network.

[0229] 705: The terminal is in an idle state or an inactive state, and monitors the alert message.

[0230] The terminal starts to monitor the Alert message, which can be based on at least one of the following conditions: the UE is in an idle state or an RRC inactive state, the UE receives Alert activation indication information, the signal strength (such as RSRP) of the current non-terrestrial network of the UE is less than a first threshold, or the signal quality (such as RSRQ) of the current non-terrestrial network of the UE is less than a second threshold. Corresponding to the second condition being met, the terminal monitors the alert message.

[0231] Optionally, the signal strength (such as RSRP) of the current non-terrestrial network of the UE is greater than or equal to the first threshold, and / or the signal quality (such as RSRQ) of the current non-terrestrial network of the UE is greater than or equal to the second threshold. Corresponding to the first condition being met, the terminal monitors the paging message.

[0232] 706: The IMS network element receives the SIP request message, which is used to initiate a call request to the UE.

[0233] The calling UE initiates a voice call service and sends a SIP Invite message to the calling IMS network element, which is used to initiate a call request to the terminal of the called party. The calling IMS network element receives the SIP Invite message and sends a SIP Invite message to the called IMS. Correspondingly, the called IMS network element receives the SIP invite message. It should be noted that the SIP Invite message transmitted between the UE and the IMS network element may be processed by each IMS network element before being transmitted to the next node. For example, the first request message is transmitted from the calling UE to the called UE, and needs to pass through the P-CSCF of the calling UE, the S-CSCF of the calling UE, the S-CSCF of the called UE, the P-CSCF of the called UE, and finally the P-CSCF of the called UE. Therefore, the SIP Invite message may be processed (for example, some or all information in the message header is added, deleted, or modified) by the P-CSCF of the calling UE, the S-CSCF of the calling UE, the S-CSCF of the called UE, and the P-CSCF of the called UE. This description applies to all subsequent SIP messages in the embodiments.

[0234] 707: The called IMS network element sends a SIP request message to the UPF. Correspondingly, the UPF receives the SIP request message.

[0235] The message is sent in the form of an IP packet.

[0236] 708: The UPF sends a downlink data notification to the SMF. Correspondingly, the SMF receives the downlink data notification.

[0237] Specifically, when the UPF determines that the IMS PDU session of the UE does not have corresponding RAN side tunnel information (AN Tunnel info), the SIP request message is cached, and a downlink data notification message is sent to the SMF, which is used to indicate that the UE has arrived downlink data. The message includes an N4 session identifier, which is associated with the IMS PDU session of the UE (the identifier of the associated IMS PDU session).

[0238] 709: The SMF sends an N1N2 message to the AMF. Correspondingly, the AMF receives the N1N2 message.

[0239] The SMF calls the service provided by the AMF and sends an N1N2 message to the AMF.

[0240] The N1 message is a message sent by the SMF to the UE through the AMF, the N2 message is a message sent by the SMF to the RAN through the AMF, and the N1N2 message is used to activate an IMS PDU session or a QoS flow.

[0241] 710: The AMF determines that the UE is in an idle state or an inactive state, and sends a paging message or an alert message to the RAN. Correspondingly, the RAN receives the paging message or the alert message.

[0242] Specifically, the AMF can send a paging message or an alert message to the RAN based on an alert policy.

[0243] The alert policy can specifically include: paging the UE by sending only an alert message, or paging the UE by first performing paging and then performing alert paging. Optionally, the alert policy can also include the number of times of sending the paging message, the number of times of sending the alert message, and the like.

[0244] Optionally, the alert policy can also include: whether to continue to send the alert message to page the UE if no response of the UE is received within a first time length. For example, the first time length is an alert response time length, that is, a maximum time length for the network to wait for a response of the UE after sending the alert to the UE. If the terminal sends an alert response such as a service request message to the network within the alert response time length, the voice call can be connected. If the terminal does not send the alert response, that is, the service request message, within the alert response time length, the voice call cannot be connected, and the network triggers a missed call information reminder.

[0245] Optionally, in the case where the voice call cannot be connected, the alert policy can also include: whether to continue to send the alert message to page the UE, so as to enable the UE to obtain the missed call information reminder as soon as possible. In this strategy, it can be understood that the alert sent within the alert response time length is used to enable the terminal to respond to the network to connect the call, and the alert sent after the alert response time length is used to enable the terminal to respond to the network to obtain the missed call information reminder.

[0246] Optionally, the paging / alert message sent by the AMF to the RAN can also include the alert policy, which is used by the RAN to determine the specific mechanism of sending the paging or the alert to the UE based on the alert policy. The alert policy used by the AMF can be the same as the alert policy sent by the AMF to the RAN, or can be different.

[0247] 711: The RAN sends an alert message to the UE.

[0248] Specifically, the RAN can send an Alert to the UE based on a local policy or a policy from the AMF, or send a paging and an Alert.

[0249] 711: The UE receives the alert message, rings and prompts the user through the interface.

[0250] The UE can prompt the user to perform a pointing operation through the interface, such as moving the UE to an open area, adjusting the direction in which the UE is placed, or moving to an area where the satellite signal is stronger. Optionally, as the user performs the pointing operation on the UE, the non-terrestrial network of the UE meets the first condition, that is, the UE is considered to be successfully pointed.

[0251] Optionally, if the UE receives an indication of the response time of the Alert, such as a first time, a corresponding timer, such as a first timer, can be started. The timer can also be displayed on the screen through the UI, for example, by counting down to remind the user to successfully point within the remaining time, and then the call can be connected.

[0252] Optionally, if the UE is successfully pointed within the first time, that is, the signal of the non-terrestrial network of the UE meets the first condition, the UE can send an Alert response message and perform the following operations.

[0253] 712: The UE sends a service request message to the AMF. Correspondingly, the AMF receives the service request message.

[0254] The UE sends a service request message to perform a service request procedure. After the service request procedure is performed, the IMS PDU session of the terminal is activated, that is, the user plane channel of the PDU session is established, so that data can be transmitted.

[0255] The UE sends a service request message to the AMF, which can correspond to the case where the second message in the foregoing embodiments is a service request message.

[0256] 713: The UPF sends a SIP request message to the UE through the RAN. Correspondingly, the UE receives the SIP request message.

[0257] According to the foregoing steps 707-708, the UPF caches the SIP request (SIP Invite) message.

[0258] 714: The UE performs other steps of call setup with the IMS network element, and the call is connected.

[0259] After the UE receives the SIP invite message, it sends a SIP 180 or 183 response message to the IMS network element, performs other steps of subsequent IMS call setup, and the call is connected.

[0260] Optionally, if the UE fails to access the satellite in the first time period, i.e., the signal of the non-terrestrial network of the UE does not satisfy the first condition in the first time period, the UE fails to send the Alert response, i.e., the UE fails to send the message to the AMF in the first time period, the UE performs the following operation.

[0261] 715: The IMS network element waits for a timeout, generates a power failure reminder, and sends the power failure reminder to a short message service center, e.g., an SMSC. Correspondingly, the SMSC receives the power failure reminder.

[0262] Optionally, the IMS waits for a timeout, i.e., the IMS sends the SIP invite message to the UE, and does not receive the SIP 180 / 183 response from the UE within a specific time period, and then the IMS network element can send the information of the power failure reminder to the short message service center (SMSC).

[0263] The SMSC is a service processing system independent of the wireless network, and is mainly used for submitting, storing, and forwarding short messages.

[0264] Optionally, although the terminal side access telephone call waits for a timeout, the terminal can continue to remind the user to adjust the terminal to receive the signal scenario to receive the power failure reminder.

[0265] If the UE successfully accesses the satellite after the first time period, i.e., the signal of the non-terrestrial network of the UE satisfies the first condition, the UE can perform the following operation.

[0266] 716: The UE sends a registration request message. Correspondingly, the AMF receives the registration request message.

[0267] After the UE successfully accesses the satellite, the UE determines whether there is an unresponded Alert message. If there is an unresponded Alert message, the UE can initiate a registration process to the network.

[0268] Optionally, the registration request message can include indication information, which indicates that the terminal initiates the registration process because of the unresponded Alert message, or indicates that the registration message is triggered by the terminal receiving the Alert message.

[0269] Optionally, the UE can send the registration request message to the AMF through the RAN, which can correspond to the case that the second message in the foregoing embodiment is the registration request message. Subsequently, the registration process of the UE further includes that the AMF interacts with the UDM to notify the UE online.

[0270] 717: The SMSC sends the power failure reminder short message to the UE. Correspondingly, the UE receives the power failure reminder short message.

[0271] Specifically, after the UE registers the network, the SMSC can obtain the UE online notification from the UDM, and then the SMSC sends the power leakage reminder message to the UE.

[0272] Therefore, the UE receives the power leakage reminder message, and the user can select whether to initiate a callback to the calling number based on the power leakage reminder message.

[0273] Embodiment two, the first message does not carry the information of the communication service initiator, and the response to the first message does not support establishing a session corresponding to the communication service.

[0274] As shown in FIG. 8, the method can include the following steps.

[0275] 801: The IMS network element receives a SIP request message for initiating a call request to the UE.

[0276] Optionally, before step 801, the foregoing steps 701-705 can be performed, and specific reference can be made to the foregoing related content. Since the embodiment does not support establishing a session corresponding to the communication service, the UE registration process can not include the indication of the alert response duration such as the first duration in the registration receiving message sent by the AMF to the UE.

[0277] 802: The IMS network element sends a SIP request message to the UPF. Correspondingly, the UPF receives the SIP request message.

[0278] 803: The UPF sends a downlink data notification to the SMF. Correspondingly, the SMF receives the downlink data notification.

[0279] 804: The SMF sends an N1N2 message to the AMF. Correspondingly, the AMF receives the N1N2 message.

[0280] 805: The AMF determines that the UE is in an idle state or an inactive state, and sends a paging message or an alert message to the RAN. Correspondingly, the RAN receives the paging message or the alert message.

[0281] 806: The RAN sends an alert message to the UE.

[0282] 807: The UE receives the alert message, rings, and prompts the user through an interface.

[0283] The UE can prompt the user through an interface to adjust the receiving state of the non-terrestrial network signal to obtain the information of the calling party.

[0284] 808: The AMF or the RAN sends a notification message to the IMS network element for terminating the call. Correspondingly, the IMS receives the notification message.

[0285] In steps 805 and 806, when the AMF or the RAN determines to send the Alert message to the UE, the AMF or the RAN can send a notification message to the IMS, which is used to indicate that the IMS network terminates the call. Further, the IMS network can trigger the power-off reminder.

[0286] 809: The IMS network element sends the power-off reminder to the SMSC. Correspondingly, the SMSC receives the power-off reminder.

[0287] After step 807, the user makes the UE star successfully according to the interface prompt of the UE, that is, the signal of the non-terrestrial network of the UE satisfies the first condition, and the UE can perform the following operations.

[0288] 810: The UE sends a registration request message. Correspondingly, the AMF receives the registration request message.

[0289] After the UE star is successful, it is determined whether there is an unresponded Alert message. When there is an unresponded Alert message, the UE can initiate a registration process to the network.

[0290] Optionally, the registration request message can include indication information, which is used to indicate that the terminal initiates the registration process because of the unresponded Alert message, or is used to indicate that the registration message is triggered because the terminal receives the Alert message.

[0291] Optionally, the UE can send the registration request message to the AMF through the RAN, which can correspond to the case that the second message in the foregoing embodiment is the registration request message.

[0292] 811: Other steps of the UE registration process.

[0293] Subsequently, the UE registration process further includes that the AMF interacts with the UDM to send the UE online notification.

[0294] 812: The SMSC sends a power-off reminder short message to the UE. Correspondingly, the UE receives the power-off reminder short message.

[0295] After the UE registers the network, the SMSC can obtain the UE online notification from the UDM, and push the power-off reminder short message to the UE.

[0296] Therefore, the UE receives the power-off reminder short message, and the user can select whether to initiate a callback to the calling number based on the power-off reminder short message.

[0297] Optionally, the UE performs the star operation, and when the non-terrestrial network meets the first condition, the UE initiates a call request according to the caller number information included in the electric leakage reminder, for example, performs step 813: the UE sends an SIP request message to the IMS, and the called number in the SIP request message is the caller number included in the electric leakage reminder. Correspondingly, the IMS receives the SIP request message, and subsequently can perform other steps of IMS call establishment, and the phone is connected.

[0298] Embodiment three, the first message does not carry the information of the initiator of the communication service, and in response to the fact that the first message does not support the establishment of a session corresponding to the communication service, the information of the initiator is sent to the terminal through signaling (for example, a NAS message).

[0299] As shown in FIG. 9, the method can include the following steps.

[0300] 901: The IMS network element receives an SIP request message for initiating a call request to the UE.

[0301] 902: The IMS network element sends the SIP request message to the UPF. Correspondingly, the UPF receives the SIP request message.

[0302] 903: The UPF sends a downlink data notification to the SMF. Correspondingly, the SMF receives the downlink data notification.

[0303] 904: The SMF sends an N1N2 message to the AMF. Correspondingly, the AMF receives the N1N2 message.

[0304] 905: The AMF determines that the UE is in an idle state or an inactive state, and sends a paging message or an alert message to the RAN. Correspondingly, the RAN receives the paging message or the alert message.

[0305] 906: The RAN sends the alert message to the UE.

[0306] 907: The UE receives the alert message, rings, and prompts the user through an interface.

[0307] The UE can prompt the user through an interface to adjust the reception state of the non-terrestrial network signal to obtain the information of the caller.

[0308] 908: The AMF or the RAN sends a notification message to the IMS network element for terminating the call. Correspondingly, the IMS receives the notification message.

[0309] 909: The AMF obtains the information of the caller from the IMS network element.

[0310] After step 907, the user adjusts the non-terrestrial network signal of the UE to meet the first condition according to the prompt of the interface of the UE, and the UE can perform the following operations.

[0311] 910: The UE sends a registration request message. Correspondingly, the AMF receives the registration request message.

[0312] 911: Other steps of the UE registration procedure.

[0313] 912: The SMF sends a message to the UE, for example, through a NAS message, carrying the information of the caller. Correspondingly, the UE receives the NAS message.

[0314] Unlike the aforementioned embodiment one and embodiment two, the core network can send the information of the caller, such as the phone number information, to the UE through the NAS message, so that the user can select whether to initiate a callback to the caller number later based on the information of the caller. For example, the UE can send a SIP request message to the IMS according to the caller’s phone number information carried in the NAS message in step 912, and the called number in the SIP request message is the caller’s phone number carried in the NAS message in step 912. Other steps of IMS call establishment can be performed, and the phone is connected.

[0315] Embodiment four, the first message carries the information of the communication service initiator, and the establishment of the session corresponding to the communication service is supported in response to the first message.

[0316] As shown in FIG. 10, the method can include the following steps.

[0317] 1001: The IMS network element receives a SIP request message for initiating a call request to the UE.

[0318] 1002: The IMS network element sends a SIP request message to the UPF. Correspondingly, the UPF receives the SIP request message.

[0319] 1003: The UPF sends a downlink data notification to the SMF. Correspondingly, the SMF receives the downlink data notification.

[0320] 1004: The SMF sends an N1N2 message to the AMF. Correspondingly, the AMF receives the N1N2 message.

[0321] 1005: The AMF determines that the UE is in an idle state or an inactive state, and sends a paging message or an alert message to the RAN. Correspondingly, the RAN receives the paging message or the alert message.

[0322] 1006: The RAN sends an alert message to the UE, carrying the information of the caller.

[0323] The alert message Alert can carry the information of the caller, such as the phone number information of the caller, or whether the caller is a pre-configured user, such as a family member or a white list user, etc.

[0324] 1007: The UE receives the alert message, rings and prompts the user through the interface.

[0325] The UE can prompt the user through the interface, such as notifying the user to adjust the receiving state of the non-terrestrial network signal. Optionally, the UE can display the incoming call information, such as the information of the caller, such as the phone number information of the caller, or whether the caller is a pre-configured user.

[0326] In this implementation, the user can determine whether to adjust the receiving state of the non-terrestrial network signal of the terminal, such as whether to perform the star operation on the terminal to connect the call, through the information of the caller of the current call prompted by the interface, so that the processing of the communication service is more flexible and adaptive, meets the needs of different scenarios, and can improve the user experience. For example, the interface of the terminal displays that the caller of the current call is a pre-configured family member, and the user determines that the star operation needs to be performed to connect the incoming call; or the interface of the terminal displays that the caller of the current call is an unknown number or a non-pre-configured user number, and the user determines that the star operation does not need to be performed and the call can be rejected.

[0327] Optionally, if the UE successfully performs the star operation within the first time period, that is, the signal of the non-terrestrial network of the UE meets the first condition, the UE can send an Alert response message and perform the following operations.

[0328] 1008: The UE sends a service request message to the AMF. Correspondingly, the AMF receives the service request message.

[0329] The UE sends a service request message to perform a service request process. After the service request process is completed, the IMS PDU session of the terminal is activated, that is, the user plane channel of the PDU session is established, so that data can be transmitted.

[0330] The UE sends a service request message to the AMF, which can correspond to the case where the second message in the foregoing embodiments is a service request message.

[0331] 1009: The UPF sends a SIP request message to the UE through the RAN. Correspondingly, the UE receives the SIP request message.

[0332] 1010: The UE and the IMS network element perform other steps of call establishment, and the call is connected.

[0333] After the UE receives the SIP invite message, the UE sends a SIP 180 or 183 response message to the IMS network element, performs other steps of subsequent IMS call establishment, and the phone is connected.

[0334] Optionally, if the UE fails to access the satellite within the first time period, i.e., the signal of the non-terrestrial network of the UE does not satisfy the first condition within the first time period, the UE cannot send an Alert response, i.e., the UE cannot send a service request message to the AMF within the first time period, the following operations are performed.

[0335] 1011: The UE displays the information of the unanswered voice call.

[0336] Specifically, the UE can display the unanswered incoming call information (i.e., missed call) in the call record through the interface based on the caller information carried in the alert message received in the foregoing step 1007. Subsequently, the user can perform satellite access and redialing based on the missed call.

[0337] Optionally, 1012: The UE sends a SIP request message to the IMS network element to initiate a call request. Correspondingly, the IMS receives the SIP request message. Subsequently, other steps of IMS call establishment can be performed, and the call is connected.

[0338] Optionally, in this embodiment, if the call fails to be connected (e.g., the caller terminates the call, the IMS network terminates, or the called party does not respond, etc.), the network can send a missed call reminder message to the UE when the UE enters the connected state again. Specifically, the IMS sends a missed call reminder to the SMSC, and the SMSC sends a missed call reminder message to the UE after obtaining the UE online notification from the UDM. The specific process can be referred to the description of the foregoing steps 808-812, and will not be described here.

[0339] Embodiment five: The first message carries information of a communication service initiator, and a session corresponding to the communication service is not supported in response to the first message.

[0340] As shown in FIG. 11, the method can include the following steps.

[0341] 1101: The IMS network element receives a SIP request message for initiating a call request to the terminal.

[0342] Optionally, before step 1101, the foregoing steps 701-705 can be performed, and the specific process can be referred to the foregoing related content. Since the embodiment does not support establishment of a session corresponding to the communication service, the indication of the Alert response time period (e.g., the first time period) can not be included in the registration reception message sent by the AMF to the UE in the UE registration process.

[0343] 1102: The IMS network element sends a SIP request message to the UPF. Correspondingly, the UPF receives the SIP request message.

[0344] 1103: The UPF sends a downlink data notification to the SMF. Correspondingly, the SMF receives the downlink data notification.

[0345] 1104: The SMF sends an N1N2 message to the AMF. Correspondingly, the AMF receives the N1N2 message.

[0346] 1105: The AMF determines that the UE is in an idle state or an inactive state, and sends a paging message or an alert message to the RAN. Correspondingly, the RAN receives the paging message or the alert message.

[0347] 1106: The RAN sends the alert message to the UE, carrying information of the calling party.

[0348] The alert message Alert can carry information of the calling party, such as telephone number information of the calling party, or whether the calling party is a pre-configured user, such as a family member or a whitelist user.

[0349] 1107: The UE receives the alert message, rings, and prompts the user through an interface.

[0350] The UE can prompt the user through an interface, such as notifying the user to adjust the reception state of the non-terrestrial network signal.

[0351] Optionally, the UE can display missed call information, such as information of the calling party, such as telephone number information of the calling party, or whether the calling party is a pre-configured user.

[0352] Optionally, the UE performs a star operation, and when the non-terrestrial network meets the first condition, performs step 1108: The UE sends a SIP request message to an IMS network element, for initiating a call request. Subsequently, other steps of IMS call establishment can be performed, and the phone is connected.

[0353] The various embodiments mentioned in the foregoing of the present application can be combined without limitation as long as the schemes do not contradict each other.

[0354] The above mainly introduces the schemes provided by the present application from the perspective of interaction between various network nodes. Correspondingly, the present application also provides a communication apparatus, which can be each communication apparatus or node in the above method embodiments, or a component such as a chip that can be used for the above communication apparatus or node.

[0355] It can be understood that, in order to implement the above functions, the communication device includes hardware structures and / or software modules corresponding to the functions. Those skilled in the art should clearly understand that, in combination with the unit and algorithm operation of the examples described in the embodiments disclosed in the present application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in hardware or computer software driven hardware depends on the specific application of the technical solution and the design constraints. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0356] It should be understood that the above describes the interaction between each network element node only by way of example. In fact, the processing performed by the above communication device or node is not limited to being performed only by a single network element.

[0357] The present application can divide the functional modules of the communication device according to the above method examples. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or software functional module. It can be understood that the division of modules in the present application is illustrative and is only a logical functional division. Actual implementation can have another division manner.

[0358] For example, in the case of dividing each functional module in an integrated manner, FIG. 12 shows a structural schematic diagram of a communication device 1200. The communication device 1200 includes an interface module 1201.

[0359] In some embodiments, the communication device 1200 can further include a storage module (not shown in FIG. 12) for storing program instructions and data. The communication device 1200 can be used to implement the functions of each network element or node in the above embodiments.

[0360] For example, the communication device 1200 can be a terminal in each of the embodiments described in FIGS. 5-11.

[0361] The interface module 1201 can be used to receive a first message, the first message being used to call the terminal through a non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network.

[0362] When the signal of the non-terrestrial network satisfies a first condition, in response to the first message, the interface module 1201 can also be used to send a second message, the second message being used to establish a communication connection with the non-terrestrial network; the first condition includes at least one of the following: the signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or the signal quality of the non-terrestrial network is greater than or equal to a second threshold value.

[0363] In an embodiment, the first message comprises indication information corresponding to an initiator of the communication service, the indication information being used to indicate whether the initiator belongs to a pre-configured user or to indicate a second identifier corresponding to the initiator, the second identifier being telephone number information.

[0364] In an embodiment, the interface module 1201 can further be configured to receive a third message, the third message being used to indicate a non-responded communication service, the third message comprising a second identifier corresponding to an initiator of the communication service, the second identifier being telephone number information.

[0365] In an embodiment, the first message comprises a first identifier corresponding to the terminal, a length of the first identifier being less than a first value, the first value being a length of an identifier of the terminal carried in a paging message used to page the terminal.

[0366] In an embodiment, the interface module 1201 can further be configured to receive a fourth message, the fourth message being used to indicate that the terminal detects the first message.

[0367] In an embodiment, the fourth message comprises a first time length, the first time length being used to indicate a maximum time length between a time when the terminal receives the first message and a time when the terminal sends the second message.

[0368] In an embodiment, the interface module 1201 can further be configured to send a fifth message, the fifth message being used to indicate that the terminal has a capability of detecting the first message.

[0369] In an embodiment, the interface module 1201 can further be configured to detect the first message, comprising: detecting the first message when the terminal is in an idle state or an inactive state and it is determined that a signal reception indicator of the non-terrestrial network satisfies a second condition, the second condition comprising at least one of: a signal strength of the non-terrestrial network being less than the first threshold value; or a signal quality of the non-terrestrial network being less than the second threshold value.

[0370] In an embodiment, the second message is a service request message used to request establishment of a session corresponding to the communication service; or the second message is a registration request message used to register the terminal to a network.

[0371] In an embodiment, the communication apparatus 1200 further comprises a processing module 1202, the processing module 1202 can be configured to start a first timer, wherein the first timer corresponds to a first time length, the first timer being used to prompt a user to adjust a non-terrestrial network signal reception scenario of the terminal before the first timer expires.

[0372] In an embodiment, the first timer is not expired, and the signal of the non-terrestrial network satisfies the first condition, the interface module 1201 can be configured to send the second message, the second message being a service request message.

[0373] In an embodiment, the first timer is expired, and the signal of the non-terrestrial network satisfies the first condition, the interface module 1201 can be configured to send the second message, the second message being a registration request message.

[0374] In an embodiment, in response to the first message, the processing module 1202 can be configured to start a ring and display a notification, the ring and / or the notification being used to indicate that the terminal has the communication service, and the notification being further used to prompt the user to adjust the non-terrestrial network signal receiving scenario of the terminal.

[0375] In addition, the communication apparatus 1200 can be configured to implement the functions of the network device in the above embodiments. FIG. 12 shows a structural schematic diagram of a communication apparatus 1200. For example, the communication apparatus 1200 is the network device in the above embodiment of FIG. 5, or the AMF or the RAN node in the above embodiments of FIGS. 7-11.

[0376] In an embodiment, when the terminal is in an idle state or an inactive state, the interface module 1201 can be configured to send a first message, the first message being used to call the terminal through a non-terrestrial network or notify the terminal of a communication service through the non-terrestrial network, and the terminal communicating through the non-terrestrial network; and the interface module 1201 is further configured to receive a second message, the second message being used to establish a communication connection between the terminal and the non-terrestrial network; wherein the second message is sent by the terminal in response to the first message when a signal of the non-terrestrial network satisfies a first condition; and the first condition includes at least one of the following: the signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or the signal quality of the non-terrestrial network is greater than or equal to a second threshold value.

[0377] In an embodiment, the first message includes a first identifier corresponding to the terminal, and the length of the first identifier is less than a first value, the first value being the length of an identifier of the terminal carried in a paging message used to page the terminal.

[0378] In an embodiment, the interface module 1201 can be configured to send the first message according to a first strategy, the first strategy including at least one of the following: calling the terminal through the first message in the non-terrestrial network, or calling the terminal through the first message after failing to call the terminal through a paging message in the non-terrestrial network, or calling the terminal by alternately sending the paging message and the first message in the non-terrestrial network.

[0379] In an embodiment, the interface module 1201 can be configured to receive a sixth message, the sixth message comprising indication information corresponding to an initiator of the communication service, the indication information indicating whether the initiator belongs to a preconfigured user or indicating a second identifier corresponding to the initiator, the second identifier being telephone number information.

[0380] In an embodiment, the first message comprises indication information corresponding to an initiator of the communication service.

[0381] In an embodiment, the interface module 1201 can be configured to send a third message to the terminal, the third message being used to indicate that the terminal has an unresponded communication service, the third message comprising a second identifier corresponding to an initiator of the communication service, the second identifier being telephone number information.

[0382] In an embodiment, the interface module 1201 can be configured to send a fourth message to the terminal, the fourth message being used to instruct the terminal to detect the first message.

[0383] In an embodiment, the fourth message comprises a first time length, the first time length being used to indicate a maximum time length between receiving the first message and sending the second message by the terminal.

[0384] In an embodiment, the interface module 1201 can be configured to receive a fifth message from the terminal, the fifth message being used to indicate that the terminal has the capability of detecting the first message.

[0385] In an embodiment, the second message is a service request message used to request establishment of a session corresponding to the communication service, or the second message is a registration request message used to register the terminal to a network.

[0386] In summary, when the communication apparatus 1200 is configured to implement the functions performed by the communication apparatus or node in the above-mentioned embodiments, other functions that the communication apparatus 1200 can implement can refer to the related descriptions of any of the above-mentioned embodiments.

[0387] In a simple embodiment, those skilled in the art can conceive that the communication apparatus 1200 can adopt the form shown in FIG. 4. For example, the processor 401 in FIG. 4 can execute the above-mentioned method by invoking the computer execution instructions stored in the memory 403, so that the communication apparatus 400 executes the method described in the above-mentioned method embodiments.

[0388] For example, the functions / implementation processes of the processing module 1202 in FIG. 12 can be implemented by the processor 401 in FIG. 4.

[0389] For example, the functions / implementation procedures of the interface module 1201 in FIG. 12 can be implemented by the communication interface 404 in FIG. 4.

[0390] It can be understood that one or more of the above modules or units can be implemented in software, hardware or a combination of both. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in the memory, and the processor can be used to execute the program instructions and implement the above method procedures. The processor can be built in the SoC (System on Chip) or the ASIC, or be a separate semiconductor chip. The processor further includes the necessary hardware accelerators, such as the field programmable gate array (FPGA), the programmable logic device (PLD), or the logic circuit implementing the special logic operation, in addition to the core for executing the software instructions to perform the operation or processing.

[0391] When any of the above modules or units is implemented in hardware, the hardware can be any one or any combination of the CPU, the microprocessor, the digital signal processing (DSP) chip, the microcontroller unit (MCU), the artificial intelligence processor, the ASIC, the SoC, the FPGA, the PLD, the special purpose digital circuit, the hardware accelerator or the non-integrated discrete device, which can run the necessary software or be independent of the software to execute the above method procedures.

[0392] In a possible implementation, the present application further provides a chip system, including at least one processor and an interface, the at least one processor is coupled with the memory through the interface, and when the at least one processor executes the computer program or instructions in the memory, the method in any of the above method embodiments is executed. In a possible implementation, the chip system further includes the memory. Optionally, the chip system can be composed of a chip, or include the chip and other discrete devices, and the present application does not make a specific limitation thereon.

[0393] Optionally, the present application also provides a computer readable storage medium. All or part of the processes in the above method embodiments can be instructed by a computer program to relevant hardware to complete, the program can be stored in the above computer readable storage medium, and the program can include the processes of the above method embodiments when executed. The computer readable storage medium can be an internal storage unit of the communication device in any of the above embodiments, such as a hard disk or a memory of the communication device. The computer readable storage medium can also be an external storage device of the communication device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the communication device. Further, the computer readable storage medium can include both the internal storage unit and the external storage device of the communication device. The computer readable storage medium is used to store the computer program and other programs and data required by the communication device. The computer readable storage medium can also be used to temporarily store data that has been output or will be output.

[0394] In a possible implementation, the present application also provides a computer program product. All or part of the processes in the above method embodiments can be instructed by a computer program to relevant hardware to complete, the program can be stored in the above computer program product, and the program can include the processes of the above method embodiments when executed.

[0395] In a possible implementation, the present application also provides a computer instruction. All or part of the processes in the above method embodiments can be instructed by a computer instruction to relevant hardware (such as a computer, a processor, a network device, or a terminal device, etc.) to complete. The program can be stored in the above computer readable storage medium or the above computer program product.

[0396] In a possible implementation, the present application also provides a communication system, including the terminal and the network device in the above embodiments. Exemplarily, the network device can be a mobility management device or an access network device.

[0397] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional modules is taken as an example for illustration. In actual application, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the above described functions.

[0398] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. For example, the embodiments of the apparatus described above are merely schematic, and the division of the modules or units is merely logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different units, or the among different units, can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0399] The units described as separated components can or can not be physically separated, and the components displayed as units can be located in one place or can be distributed to multiple places. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments.

[0400] In addition, each functional unit in the embodiments of the present application can be integrated in a processing unit, or each unit can exist physically as a separate unit, or two or more units can be integrated in one unit. The integrated unit can be implemented in the form of hardware, or in the form of a software functional unit.

[0401] The above describes only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method applied to a terminal comprises: receiving a first message, the first message being used for calling the terminal through a non-terrestrial network or informing the terminal of existence of a communication service through the non-terrestrial network; when a signal of the non-terrestrial network meets a first condition, sending a second message in response to the first message, the second message being used for establishing a communication connection with the non-terrestrial network; the first condition comprises at least one of the following: a signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or a signal quality of the non-terrestrial network is greater than or equal to a second threshold value.

2. The method of claim 1, wherein, the first message comprises indication information corresponding to an initiator of the communication service, the indication information being used for indicating whether the initiator belongs to a pre-configured user or indicating a second identifier corresponding to the initiator, the second identifier being telephone number information.

3. The method according to claim 1 or 2, characterized in that, The method further comprises: receiving a third message, the third message being used for indicating an unresponded communication service, the third message comprising a second identifier corresponding to an initiator of the communication service, the second identifier being telephone number information.

4. The method according to any one of claims 1 to 3, characterized in that, the first message comprises a first identifier corresponding to the terminal, a length of the first identifier being less than a first value, the first value being a length of an identifier of the terminal carried when the terminal is paged through a paging message.

5. The method according to any one of claims 1 to 4, characterized in that, Before the receiving the first message, the method further comprises: receiving a fourth message, the fourth message being used for instructing the terminal to detect the first message.

6. The method of claim 5, wherein, the fourth message comprises a first time length, the first time length being used for indicating a maximum time length between receiving the first message and sending the second message by the terminal.

7. The method according to any one of claims 1 to 6, characterized in that, Before the receiving the first message, the method further comprises: sending a fifth message, the fifth message being used for indicating that the terminal has a capability of detecting the first message.

8. The method according to any one of claims 5-7, characterized in that, The detecting the first message comprises: when the terminal is in an idle state or an inactive state and it is determined that a signal reception index of the non-terrestrial network meets a second condition, detecting the first message, the second condition comprising at least one of the following: a signal strength of the non-terrestrial network is less than the first threshold value; or a signal quality of the non-terrestrial network is less than the second threshold value.

9. The method according to any one of claims 1 to 8, characterized in that, the second message is a service request message used for requesting establishment of a session corresponding to the communication service; or the second message is a registration request message used for registering the terminal to a network.

10. The method according to any one of claims 1 to 9, characterized in that, After the receiving the first message, the method further comprises: starting a first timer by the terminal, wherein the first timer corresponds to a first time length, and the first timer is used for prompting a user to adjust a non-terrestrial network signal reception scenario of the terminal before the first timer expires.

11. The method of claim 10, wherein, The sending the second message comprises: when the first timer does not expire and the signal of the non-terrestrial network meets the first condition, sending the second message, the second message being the service request message.

12. The method of claim 10, wherein, The sending the second message comprises: when the first timer expires and the signal of the non-terrestrial network meets the first condition, sending the second message, the second message being the registration request message.

13. The method according to any one of claims 1 to 12, characterized in that, The method further comprises: In response to the first message, the terminal rings and displays a notification, the ringing and / or the notification being used to indicate that the terminal has the communication service, and the notification being further used to prompt a user to adjust a non-terrestrial network signal receiving scenario of the terminal.

14. A communication method, comprising: The method is applied to a network device, and the method comprises: When a terminal is in an idle state or an inactive state, a first message is sent, the first message being used to call the terminal through a non-terrestrial network or to notify the terminal that there is a communication service through the non-terrestrial network, wherein the terminal communicates through the non-terrestrial network; a second message is received, the second message being used to establish a communication connection between the terminal and the non-terrestrial network; wherein the second message is sent in response to the first message when a signal of the non-terrestrial network satisfies a first condition. The first condition comprises at least one of the following: a signal strength of the non-terrestrial network is greater than or equal to a first threshold value; or a signal quality of the non-terrestrial network is greater than or equal to a second threshold value.

15. The method of claim 14, wherein, The first message comprises a first identifier corresponding to the terminal, and a length of the first identifier is less than a first value, the first value being a length of an identifier of the terminal carried in a paging message used to page the terminal.

16. The method according to claim 14 or 15, characterized in that The first message is sent in accordance with a first strategy, the first strategy comprising at least one of the following: calling the terminal through the first message in the non-terrestrial network, or calling the terminal through the first message after calling the terminal through a paging message fails in the non-terrestrial network, or calling the terminal by alternately sending the paging message and the first message in the non-terrestrial network. The method further comprises:

17. The method according to any one of claims 14-16, characterized by, a sixth message is received, the sixth message comprising indication information corresponding to an initiator of the communication service, the indication information indicating whether the initiator belongs to a preconfigured user or indicating a second identifier corresponding to the initiator, the second identifier being telephone number information. The first message comprises indication information corresponding to an initiator of the communication service.

18. The method of claim 17, wherein, The method further comprises:

19. The method according to any one of claims 14-18, characterized by, a third message is sent to the terminal, the third message being used to indicate that the terminal has an unresponded communication service, and the third message comprising a second identifier corresponding to the initiator of the communication service, the second identifier being telephone number information. Before the first message is sent, the method further comprises:

20. The method according to any one of claims 14-19, characterized by, a fourth message is sent to the terminal, the fourth message being used to instruct the terminal to detect the first message. The fourth message comprises a first time length, the first time length being used to indicate a maximum time length between receiving the first message and sending the second message by the terminal.

21. The method of claim 20, wherein, Before the first message is sent, the method further comprises:

22. The method according to any one of claims 14-21, characterized by, a fifth message is received from the terminal, the fifth message being used to indicate that the terminal has a capability of detecting the first message. The second message is a service request message used to request establishment of a session corresponding to the communication service, or the second message is a registration request message used to register the terminal to a network.

23. The method according to any one of claims 14-22, characterized by, A device is configured to implement the method of any one of claims 1-13 or 14-23.

24. A communications device, characterized by The device comprises:

25. A communications device, characterized by ​ at least one processor coupled with a memory for storing programs or instructions that, when executed by the at least one processor, cause the method of any one of claims 1-13 to be performed; or cause the method of any one of claims 14-23 to be performed.

26. A computer readable storage medium having stored thereon a computer program or instructions, characterized in that, The computer program or instructions, when executed, cause the method of any one of claims 1-13 to be performed; or cause the method of any one of claims 14-23 to be performed.

27. A computer program product, comprising computer program code in said computer program product, characterised in that, The computer program code, when running on a computer, causes the method of any one of claims 1-13 to be performed; or causes the method of any one of claims 14-23 to be performed.

28. A chip or chip system, characterized by The chip or chip system is configured to implement the method of any one of claims 1-13, or to implement the method of any one of claims 14-23.

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