Communication method and communication apparatus

Abstract

Provided in the present application are a communication method and a communication apparatus. The communication method comprises: a terminal device sending a first request to a first access network device, wherein the first request is used for instructing the terminal device to request access to a core network; the terminal device establishing a connection with a second access network device; and the terminal device receiving first information from the second access network device, wherein the first information is information that the core network replies to the terminal device on the basis of the first request. The technical solution can help a terminal device to continue completing the process of accessing a core network in a scenario where the terminal device is disconnected from a first access network device before receiving first information, that is, in the case in which the terminal device has not accessed the core network.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 29, 2023, with application number 202311871702.2 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0003] Currently, the communications field has proposed a satellite network architecture with regenerative payloads. In this architecture, base stations are deployed on satellites, and ground-based mobile terminals access the core network through base stations deployed on the satellites and ground stations. The connection between the terminal and the base station is called an access connection, and the connection between the base station and the ground station is called a feeder connection.

[0004] In a satellite network architecture with a regenerative payload, the following issue may arise: during the initial access process to the core network, after a terminal sends an initial access request requesting access to the core network, the terminal device loses connection with the current base station before receiving a response message from the core network. This means that the terminal device loses connection with the current base station before completing the core network access process. For example, if the power feed connection between the base station and the ground station is unavailable when the terminal sends the initial access request to the base station, the terminal device must wait at least until the power feed connection between the base station and the ground station is restored before receiving a response message from the core network. During this time, the terminal device may lose connection with the base station.

[0005] At this time, how to ensure that the terminal can receive the reply message sent by the core network device to the terminal to complete the network access of the terminal device becomes a technical problem that needs to be solved urgently. Summary of the Invention

[0006] The present application provides a communication method and a communication device, so as to achieve a scenario in which the terminal device is disconnected from the current base station before accessing the core network, so that the terminal device can receive a reply message sent by the core network device to the terminal, so as to help the terminal device continue to complete the network access.

[0007] In the first aspect, the present application provides a communication method, which can be executed by a terminal device, or by a component configured in the terminal device (such as a chip, a chip system, etc.), or it can also be a logic module or software that can realize all or part of the terminal device functions. The present application does not limit this.

[0008] Exemplarily, the method includes: sending a first request to a first access network device, the first request being used to indicate that the terminal device requests access to the core network; establishing a connection with a second access network device and sending an identifier of the terminal device to the second access network device; receiving first information from the second access network device, the first information being information that the core network replies to the terminal device based on the first request, and the first information corresponding to the identifier of the terminal device.

[0009] Exemplarily, the first information is any one of the following information that the core network device replies to the terminal device based on the first request sent by the terminal device in the process of the terminal device accessing the core network: information used to indicate acceptance of the terminal device's access to the core network (for example, attach accept, registration accept, etc.), authentication request, N1 message, non-access stratum message (NAS message), etc.

[0010] Exemplarily, after sending the first request to the first access network device and before establishing a connection with the second access network device, the terminal device disconnects from the first access network device (for example, RRC connection, transport layer connection, the terminal device leaves the coverage of the first access network device).

[0011] In this application, the first access network device and the second access network device are deployed on a satellite.

[0012] It is understandable that, after receiving the first request, the first access network device will send the first request to the core network device when the feed connection is available. Correspondingly, after receiving the first request, the core network device will respond with information about the first request. In this application, this response information is referred to as the first information.

[0013] Specifically, in the present application, on the core network side, after receiving the first request, it will determine the second access network device used to store and forward the first reply information, and then instruct the second access network device to send the first reply information to the terminal device. On the terminal device side, a connection will be established with the second access network device that stores the first information and the terminal device identifier will be sent to the second access network device. In this way, the second access network device can determine the first reply information from the core network corresponding to the terminal device identifier to the terminal device based on the terminal device identifier, and then send the first reply information to the terminal device.

[0014] In the present application, the identifier of the terminal device is used to identify the terminal device that sends the first request in the initial access process. Exemplarily, the identifier of the terminal device can be an international mobile subscriber identification code (IMSI), a user permanent identifier (SUPI), a user hidden protection identifier (SUCI), a globally unique temporary identification (GUTI), a temporary mobile subscriber identity (TMSI), a cell radio network temporary identifier (C-RNTI), an inactive radio network temporary identifier (I-RNTI), a combination of C-RNTI and RAN identifier, a combination of I-RNTI and RAN identifier, etc.

[0015] It can be understood that through this technical solution, even if the terminal device is disconnected from the first access network device, since the terminal device will establish a connection with the second access network device that stores the first information and send the terminal device's identification to the second access network device, the second access network device can determine the first information that the core network device replies to the terminal device based on the terminal device's identification, and then send the first information to the terminal device, thereby helping the terminal device complete the process of accessing the core network.

[0016] In combination with the first aspect, in a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0017] The second access network device and the first access network device are the same access network device. This means that the access network device that sends the first message to the terminal device is the first access network device that receives the first request. Alternatively, the terminal device sends the first request to the first access network device, establishes a connection with the first access network device again, and receives the first message from the core network device that is forwarded by the first access network device to the terminal device.

[0018] Among them, the second access network device and the first access network device are different access network devices, that is, the access network device that sends the first information replied by the core network device to the terminal device and the access network device that receives the first request are not the same access network device.

[0019] In combination with the first aspect, in a possible implementation, the above method also includes: receiving second information sent by the first access network device, the second information is used to indicate the first duration; establishing a connection with the second access network device, including: establishing a connection with the second access network device after the first duration.

[0020] In this technical solution, after the first access network device receives the first request, the first access network device will determine a second access network device that can send the first information replied by the core network device to the terminal device, and determine a first duration, wherein after the first duration ends, the terminal device can establish a connection with the second access network device.

[0021] In other words, in this technical solution, the second access network device is the access network device from which the broadcast message originates, which the terminal device can detect after the first duration has expired. Alternatively, from another perspective, the first access network device indicating the first duration can be considered as indicating to the terminal device the second access network device with which a connection should be established. Furthermore, it can also be considered as indicating to the terminal device the second access network device that stores the first information replied by the core network.

[0022] That is, in this technical solution, the first access network device determines the second access network device that stores and forwards the first information replied by the core network device, and then indicates the first duration to the terminal device, so that the terminal device establishes a connection with the second access network device that stores the first information and sends the terminal device identifier to the second access network device, thereby obtaining the first information replied by the core network device and helping the terminal device complete the process of accessing the core network.

[0023] With reference to the first aspect, in a possible implementation manner, the first duration is determined by the first access network device based on ephemeris information.

[0024] Optionally, the first access network device may also determine the first duration through ephemeris information and at least one of the following information: the location of the satellite on which the second access network device is deployed, the location of the terminal device, and the current time.

[0025] In combination with the first aspect, in a possible implementation, the above method also includes: obtaining a first identifier, the first identifier is used to identify the second access network device; establishing a connection with the second access network device, including: when receiving the first identifier from the second access network device, establishing a connection with the second access network device.

[0026] The method of establishing a connection with the second access network device upon receiving the first identifier from the second access network device may also be replaced by the method of establishing a connection with the access network device that sent the message upon receiving the message including the first identifier. It is understood that in this case, the access network device that sent the message is the second access network device.

[0027] Optionally, in some implementations, obtaining the first identifier includes: receiving the first identifier from a first access network device. In this implementation, the first access network device determines a second access network device that stores and forwards the first information replied by the core network device, and then indicates the first identifier used to identify the second access network device to the terminal device, so that the terminal device establishes a connection with the second access network device that stores the first information, thereby obtaining the first information replied by the core network device and helping the terminal device complete the process of accessing the core network.

[0028] Among them, the first access network device sends a first identifier to the terminal device, which can be considered as indicating to the terminal device that a second access network device needs to establish a connection. Further, it can also be considered as a second access network device used to indicate to the terminal device that the first information replied by the core network is stored.

[0029] Optionally, in some implementations, obtaining the first identifier includes: determining the first identifier based on ephemeris information.

[0030] Exemplarily, the terminal device determines the first identifier through ephemeris information and at least one of the following information: the location of the terminal device and the current time.

[0031] In combination with the first aspect, in a possible implementation, after the terminal device determines the first identifier, the terminal device may also send the first identifier to the first access network device, so that the first identifier is sent to the core network device through the first access network device.

[0032] In this technical solution, after determining the first identifier of the second access network device to store and forward, the terminal device will send the first identifier to the core network device through the first access network device, so that the core network device can determine the second access network device to store and forward the first information replied by the core network device, thereby ensuring that the access network device receiving the first information from the core network device and the access network device establishing a connection with the terminal device are the same access network device, ensuring that the terminal device can obtain the first information replied by the core network device after the connection is established. In other words, when the terminal device sends the first identifier to the first access network device, the first identifier can be considered to be used to indicate the second access network device that sent the first information.

[0033] In combination with the first aspect, in a possible implementation, the above method also includes: establishing a connection with a third access network device; if the first information sent by the third access network device is not received within the second time period, releasing the connection with the third access network device.

[0034] In this embodiment, the third access network device may be considered as an access network device that does not store the first information replied by the core network device.

[0035] In this technical solution, if the terminal device also receives a broadcast message from a third access network device, the terminal device will also establish a connection with the third access network device. Accordingly, since the third access network device does not store the first message replied by the core network device, the third access network device will not send the first message to the terminal device. Therefore, in this technical solution, when the terminal device does not receive the first message sent by the third access network device within the second time period, it can be determined that the third access network device does not store the first message replied by the core network device, and the connection with the third access network device is released.

[0036] Optionally, the terminal device may send third information to the third access network device, where the third information is used to instruct the third access network device to send information that the core network device replies to the terminal device; receive fourth information sent by the third access network device in response to the third information, where the fourth information is used to instruct the terminal device to release the connection with the third access network device; and release the connection with the third access network device.

[0037] In this technical solution, the terminal device displays information to the third access network device through the third information, indicating that the core network device needs to reply to the terminal device; accordingly, after determining that the first information is not stored, the third access network device instructs the terminal device to release the connection between it and the third access network device.

[0038] In combination with the first aspect, in a possible implementation, the above method also includes: sending fifth information to the second access network device, the fifth information is used to instruct the second access network device to send information that the core network device replies to the terminal device.

[0039] In this technical solution, the terminal device displays information indicating that the core network device needs to reply to the terminal device to the second access network device through the fifth information. Accordingly, the second access network device responds to the fifth information and sends the first information of the core network device replying to the terminal device to the second access network device.

[0040] In the second aspect, the present application provides a communication method, applied to a first access network device, including: receiving a first request, the first request is used to indicate that the terminal device requests access to the core network; sending second information to the terminal device, the second information is used to indicate a first duration, wherein the terminal device establishes a connection with the second access network device after the first duration ends, and the second access network device is used to store the first information replied by the core network device to the terminal device based on the first request; and sending the first request to the core network device.

[0041] Among them, when the terminal device establishes a connection with the second access network device after the first time period ends, the terminal device also sends the terminal device identifier to the second access network device.

[0042] It should be noted that the fact that the second access network device is used to store the first information that the core network device replies to the terminal device based on the first request does not mean that the first information has already been stored in the second access network device. For example, the second access network device may store the first information after the first access network device sends the second information to the terminal device.

[0043] In this technical solution, the first access network device determines the second access network device that stores and forwards the first information replied by the core network device, and then indicates the first duration to the terminal device, so that the terminal device establishes a connection with the second access network device that stores the first information, thereby obtaining the first information replied by the core network device and helping the terminal device complete the process of accessing the core network.

[0044] In combination with the second aspect, in a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0045] In combination with the second aspect, in a possible implementation manner, when the second access network device and the first access network device are different access network devices, the method further includes: sending an identifier of the second access network device to the core network device.

[0046] With reference to the second aspect, in a possible implementation manner, the first duration is determined by the first access network device based on ephemeris information.

[0047] Exemplarily, the first access network device determines the first duration based on the ephemeris information and at least one of the following information: a satellite position, a position of the terminal device, and a current time.

[0048] In combination with the second aspect, in a possible implementation, when the second access network device is the first access network device, the method further includes: receiving fifth information from the terminal device, the fifth information being used to indicate information that the core network device sends to reply to the terminal device.

[0049] In a third aspect, the present application provides a communication method, applied to a first access network device, including: receiving a first request, the first request is used to indicate that the terminal device requests access to the core network; sending a first identifier to the terminal, the first identifier is used to identify a second access network device, and the second access network device is used to store the first information that the core network device replies to the terminal device based on the first request; and sending the first request to the core network device.

[0050] In this technical solution, the first access network device will determine the second access network device that stores and forwards the first information replied by the core network device, and then indicate the first identifier used to identify the second access network device to the terminal device, so that the terminal device establishes a connection with the second access network device that stores the first information and sends the identifier of the terminal device to the second access network device, thereby obtaining the first information replied by the core network device and helping the terminal device complete the process of accessing the core network.

[0051] In combination with the third aspect, in a possible implementation, the method further includes: sending a first identifier to the core network device, the first identifier being used by the core network device to determine to send the first information to the terminal device through the second access network device.

[0052] In combination with the third aspect, in a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0053] In combination with the third aspect, in a possible implementation, when the second access network device and the first access network device are the same access network device, the method further includes: receiving fifth information from the terminal device, the fifth information being used to indicate information that the core network device sends to reply to the terminal device.

[0054] In a fourth aspect, the present application provides a communication method, applied to a core network device, including: receiving a first request sent by a first access network device, the first request being used to instruct a terminal device to request access to the core network; sending a first message to a second access network device, the first message being the information that the core network device replies to the terminal device based on the first request; wherein the second access network device is determined based on any one of the following methods: the first access network device instructs the core network device, the terminal device instructs the core network device, and the core network device determines based on ephemeris information.

[0055] In combination with the fourth aspect, in a possible implementation manner, the method further includes: instructing the second access network device to delete the stored first information after a third time period.

[0056] In combination with the fourth aspect, in a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0057] In conjunction with the fourth aspect, in one possible implementation, the method further includes: indicating the location of the terminal device to the second access network device. In this technical solution, the core network device indicates the location of the terminal device to the second access network device, so that the second access network device can send a broadcast message only when it covers the terminal device, allowing the terminal device to detect the second access network device.

[0058] In a fifth aspect, the present application provides a communication method, applied to a terminal device, including: sending a first request to a first access network device, the first request being used to instruct the terminal device to request access to a core network; obtaining indication information for instructing the terminal device to access a second access network device from the first access network device or locally; the terminal device establishing a connection with the second access network device based on the indication information and sending an identifier of the terminal device to the second access network device; receiving first information from the second access network device, the first information being information that the core network replies to the terminal device based on the first request, and the first information corresponding to the identifier of the terminal device.

[0059] In combination with the fifth aspect, in a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0060] In combination with the fifth aspect, in a possible implementation method, the indication information is a first duration obtained from the first access network device, and the terminal device establishes a connection with the second access network device according to the indication information, including: establishing a connection with the second access network device after the first duration.

[0061] In combination with the fifth aspect, in a possible implementation manner, the first duration is determined by the first access network device based on ephemeris information.

[0062] In combination with the fifth aspect, in a possible implementation, the indication information is a first identifier sent by the first access network device, and the first identifier is used to identify the second access network device that stores the first information replied by the core network device.

[0063] In combination with the fifth aspect, in a possible implementation, the indication information is a first identifier determined locally by the terminal device based on the ephemeris information, and the first identifier is used to identify the second access network device that stores the first information replied by the core network device.

[0064] In the sixth aspect, the present application provides a communication method, applied to a second access network device, including: receiving first information from a core network device, the first information is the information that the core network replies to the terminal device based on a first request, the first request is used to indicate that the terminal device requests access to the core network, and the first information corresponds to the first terminal device identifier; receiving the first terminal device identifier, sending the first information to the terminal device that sent the first terminal device identifier.

[0065] In combination with the sixth aspect, in a possible implementation, the first terminal device identifier is sent by the core network device to the second access network device.

[0066] Among them, the first terminal device identifier is used to identify the terminal device that sends the first request in the initial access process. Exemplarily, the first terminal device identifier can be an international mobile subscriber identification code (IMSI), a user permanent identifier (SUPI), a user hidden protection identifier (SUCI), a globally unique temporary identification (GUTI), a temporary mobile subscriber identity (TMSI), a cell radio network temporary identifier (C-RNTI), an inactive radio network temporary identifier (I-RNTI), etc.

[0067] In a seventh aspect, the present application provides a communications device that can implement the methods described in aspects 1 to 6 and any possible implementation of aspects 1 to 6. The device includes corresponding modules for executing the aforementioned methods. The modules included in the device can be implemented in software and / or hardware.

[0068] In an eighth aspect, the present application provides a communication device comprising a processor, wherein the processor can be used to execute a computer program in a memory to implement the method described in the first to sixth aspects and any possible implementation of the first to sixth aspects.

[0069] Optionally, the device further includes a communication interface, and the processor is coupled to the communication interface. The communication interface is configured to receive signals from other communication devices outside the device and transmit them to the processor, or to transmit signals from the processor to other communication devices outside the device. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, pin, or other type of communication interface.

[0070] Optionally, the apparatus further comprises a memory, the processor being coupled to the memory. The memory is configured to store program instructions and data. The memory is coupled to the processor, and when the processor executes instructions stored in the memory, the methods described in the above aspects can be implemented.

[0071] In a ninth aspect, the present application provides a communication device comprising a processor and a communication interface, wherein the communication interface is configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device, wherein the processor implements the method described in any one of the first to fifth aspects and any possible implementation of the first to fifth aspects through a logic circuit or by executing code instructions. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, pin, or other type of communication interface.

[0072] Optionally, the device further includes a memory for storing instructions and data. The memory may be coupled to the processor, and when the processor executes the instructions stored in the memory, the method described in any one of the first to sixth aspects and any possible implementation of the first to sixth aspects is implemented.

[0073] In the tenth aspect, the present application provides a communication device comprising a processor and a memory, wherein the memory is used to store instructions and data. When the processor executes the instructions stored in the memory, it can implement the methods described in the first to sixth aspects and any possible implementation methods of the first to sixth aspects.

[0074] Optionally, the device further includes a communication interface, which is used for the device to communicate with other communication devices. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, pin or other types of communication interfaces.

[0075] In the eleventh aspect, the present application provides a computer-readable storage medium, which stores a computer program or instructions. When the computer program or instructions are executed, the method described in the first to sixth aspects and any possible implementation method of the first to sixth aspects is implemented.

[0076] In a twelfth aspect, the present application provides a computer program product comprising instructions, which, when executed, implement the method described in aspects 1 to 6 and any possible implementation of aspects 1 to 6.

[0077] In the thirteenth aspect, the present application provides a chip system comprising at least one processor for supporting the functions involved in any possible implementation of the first to fifth aspects and the first to sixth aspects, such as receiving or processing the data involved in the above method.

[0078] In one possible design, the chip system further includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0079] The chip system can be composed of chips, or can include chips and other discrete devices.

[0080] Among them, the effects that can be obtained from the second to eleventh aspects can be referred to the description in the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 shows the satellite network architecture of the transparent payload provided by this application;

[0082] FIG2 is a satellite network architecture of a regenerative payload provided by this application;

[0083] FIG3 is a schematic diagram of an access connection and a feed connection when a satellite is moving provided by the present application;

[0084] FIG4 is a schematic diagram of a process of accessing a conventional terminal device to a core network provided by the present application;

[0085] FIG5 is a schematic diagram of the process of establishing a connection between a terminal device and a core network in 4G provided by the present application;

[0086] FIG6 is a schematic diagram of the process of establishing a connection between a terminal device and a core network in 5G provided by this application;

[0087] FIG7 is a schematic flow chart of a communication method provided in one embodiment of the present application;

[0088] FIG8 is an exemplary flow chart of a communication method provided by one embodiment of the present application;

[0089] FIG9 is a schematic flow chart of a communication method provided in one embodiment of the present application;

[0090] FIG10 is an exemplary flow chart of a communication method provided by one embodiment of the present application;

[0091] FIG11 is a schematic flow chart of a communication method provided in one embodiment of the present application;

[0092] FIG12 is an exemplary flow chart of a communication method provided by one embodiment of the present application;

[0093] FIG13 is a schematic flow chart of a communication method provided in one embodiment of the present application;

[0094] FIG14 is an exemplary flow chart of a communication method provided by one embodiment of the present application;

[0095] FIG15 is a schematic flow chart of a communication method provided in one embodiment of the present application;

[0096] FIG16 is a structural diagram of a communication device provided in one embodiment of the present application;

[0097] FIG17 is a structural diagram of a communication device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0098] The technical solution in this application will be described below with reference to the accompanying drawings.

[0099] Before introducing the method provided in the embodiments of the present application, the following points are explained.

[0100] First, in this application, indications include explicit indications (also called direct indications) and implicit indications (also called indirect indications). Specifically, explicit indication information A refers to including information A; implicit indication information A refers to indicating information A through the correspondence between information A and information B and directly indicating information B. The correspondence between information A and information B can be predefined, pre-stored, pre-burned, or pre-configured; or, it can also refer to indicating information A through information B and preset rules.

[0101] Second, in this application, information C is used to determine information D, which includes both information D being determined solely based on information C and information D being determined based on information C and other information. Furthermore, information C can also be used to determine information D indirectly, for example, when information D is determined based on information E, and information E is determined based on information C.

[0102] Third, in this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship, but it does not exclude the situation where the previous and next associated objects are in an "and" relationship. The specific meaning can be understood in conjunction with the context. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, c can be single or multiple.

[0103] Fourth, in this application, prefixes such as "first" and "second" are used solely to distinguish between different items belonging to the same category and do not constrain the order, size, or quantity of the items. For example, "first message" and "second message" can refer to different messages or the same message, and this application does not limit this.

[0104] Fifth, the terms "send" and "receive" in this application refer to the direction of signal transmission. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface.

[0105] In other words, sending and receiving can be carried out between devices, for example, between a terminal device and a first access network device; or it can be carried out within a device, for example, sending or receiving between components, modules, chips, software modules or hardware modules within the device through a bus, wiring or interface.

[0106] Sixth, in this application, "when", "if" and "if" all mean that the device will take corresponding actions under certain objective circumstances, which does not limit the time, nor does it require that the device must perform judgment actions when it is implemented, nor does it mean that there are other limitations.

[0107] Seventh, in this application, words such as "example," "exemplarily," "for example," or "such as" are used to indicate examples, illustrations, or explanations. Any embodiment or design described in this application as "example," "exemplarily," "for example," or "such as" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "example," "exemplarily," "for example," or "such as" is intended to present the relevant concepts in a concrete manner.

[0108] With the development of communication technology, non-terrestrial networks (NTNs) have become a research hotspot. For example, Figures 1 and 2 illustrate two NTN network architectures provided by embodiments of the present application. Figure 1 illustrates a satellite network architecture for transparent payloads, while Figure 2 illustrates a satellite network architecture for regenerative payloads.

[0109] As shown in Figure 1, the satellite network architecture of transparent payload includes ground mobile terminals (hereinafter referred to as terminal devices), satellites, ground stations deployed on the ground, base stations deployed on the ground and core networks. Terminal devices are connected to the core network through satellites, ground stations and base stations deployed on the ground.

[0110] As shown in Figure 2, the satellite network architecture for a regenerative payload includes terminal devices, satellites, base stations deployed on the satellite, ground stations, and a core network. Terminal devices access the core network through base stations deployed on the satellite and ground stations deployed on the ground. Ground stations can also be called gateways. In other words, in a satellite network architecture for a regenerative payload, satellites have all or some of the functions of a base station.

[0111] Typically, in a satellite network architecture with regenerative payloads, the connection between a terminal device and a base station is also referred to as an access connection, and the connection between a base station and a ground station is also referred to as a feeder connection.

[0112] It should be noted that this application does not limit the specific forms of terminal devices and base stations.

[0113] In an embodiment of the present application, the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device.

[0114] The terminal device may be a device that provides voice / data, such as a handheld device or vehicle-mounted device with a wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (PLMNs). The terminal equipment in the network (PLMN), etc., is not limited to this in the embodiments of the present application.

[0115] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0116] In the embodiments of the present application, the device for realizing the function of the terminal device can be a terminal device, or a device capable of supporting the terminal device to realize the function, such as a chip system, which can be installed in the terminal device or used in combination with the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. In the embodiments of the present application, only the terminal device is used as an example for description, and the embodiments of the present application are not limited to the solutions of the embodiments of the present application.

[0117] The base station in the embodiment of the present application may be a device for communicating with a terminal device, and the base station may also be referred to as an access network device or a radio access network device. The base station in the embodiment of the present application may refer to a radio access network (RAN) node (or device) that connects a terminal device to a wireless network. A base station may broadly cover various names as follows, or replace the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), master station, secondary station, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), radio unit (RU), positioning node, etc. A base station may be a macro base station, a micro base station, a relay node, a donor node, or the like, or a combination thereof. The base station may also refer to a communication module, modem or chip used to be set in the aforementioned equipment or device. The base station may also be a mobile switching center and a device that performs the base station function in D2D, V2X, and M2M communications, a network side device in a future communication network, a device that performs the base station function in a future communication system, etc. The base station can support networks with the same or different access technologies. Optionally, the RAN node may also be a server, a wearable device, a vehicle or an on-board device, etc. For example, the access network device in the vehicle to everything (V2X) technology may be a road side unit (RSU). The embodiments of the present application do not limit the specific technology and specific device form adopted by the network equipment.In some deployments, the network devices mentioned in the embodiments of the present application may include a CU, a DU, or both a CU and a DU, or a control plane CU node (central unit-control plane (CU-CP)), a user plane CU node (central unit-user plane (CU-UP)), and a DU node. For example, the network devices may include a gNB-CU-CP, a gNB-CU-UP, and a gNB-DU.

[0118] In some deployments, multiple RAN nodes collaborate to assist terminals in achieving wireless access, with different RAN nodes implementing portions of the base station's functionality. For example, a RAN node can be a CU, DU, CU-CP, CU-UP, or RU. The CU and DU can be separate or included in the same network element, such as the BBU. The RU can be included in a radio frequency device or radio unit, such as an RRU, AAU, or RRH.

[0119] The RAN node may support one or more types of fronthaul interfaces, with different fronthaul interfaces corresponding to DUs and RUs with different functions. If the fronthaul interface between the DU and the RU is a common public radio interface (CPRI), the DU is configured to implement one or more baseband functions, and the RU is configured to implement one or more radio frequency functions. If the fronthaul interface between the DU and the RU is another type of interface, relative to the CPRI, some of the downlink and / or uplink baseband functions, such as precoding, digital beamforming (BF), or one or more of inverse fast Fourier transform (IFFT) / cyclic prefix (CP) for downlink, are moved from the DU to the RU for implementation; and for uplink, one or more of digital beamforming (BF), or fast Fourier transform (FFT) / cyclic prefix (CP) removal, are moved from the DU to the RU for implementation. In one possible implementation, the interface may be an enhanced common public radio interface (eCPRI). In the eCPRI architecture, the division between the DU and RU is different, corresponding to different types (category, Cat) of eCPRI, such as eCPRI Cat A, B, C, D, E, and F.

[0120] In one possible design, the processing unit for implementing baseband functions in the BBU is called a baseband high layer (BBH) unit, and the processing unit for implementing baseband functions in the RRU / AAU / RRH is called a baseband low layer (BBL) unit.

[0121] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. Any unit of 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.

[0122] The core network side in the embodiment of the present application may include a user plane function (UPF) of the data plane and a core network control plane. UPF is a functional unit of the user plane, which is mainly responsible for packet forwarding, quality of service (QoS) control, billing information statistics and connection to external networks, etc. It includes the relevant functions of the serving gateway (SGW) and public data network gateway (PDN-GW) of the long term evolution technology (LTE). The core network control plane is mainly responsible for business process interaction, issuing data packet forwarding policies and QoS control policies to the user plane. Exemplarily, the control plane network elements in the core network control plane mainly include: access and mobility function (AMF), session management function (SMF), policy control function (PCF), application function (AF), network exposure function (NEF), etc. Among them, the functions of each network element can be referred to the description in the relevant technology and will not be repeated here. In addition, it is noted that the various network elements involved in the embodiments of the present application may be the network elements mentioned in the above embodiments, or may be network elements having the same functions as the above network elements. For example, the application function network element may be an AF network element, or may be a network element having the same functions as the AF network element; the policy management network element may be a PCF network element, or may be a network element having the same functions as the PCF network element.

[0123] In the embodiments of the present application, the device for implementing the functions of a base station may be a base station; it may also be a device capable of supporting the base station in implementing the functions, such as a chip system, a hardware circuit, a software module, or a hardware circuit and a software module. The device may be installed in the base station or used in conjunction with the base station. In the embodiments of the present application, only the base station is used as an example for illustration, and the embodiments of the present application are not limited thereto.

[0124] It can be understood that in the satellite network architecture of regenerative payload, the satellite is mobile. Therefore, there may be a situation where the access connection between the terminal device and the base station deployed on the satellite is disconnected, also known as the access connection is unavailable, or there may be a situation where the feed connection between the base station deployed on the satellite and the ground station is disconnected, also known as the feed connection is unavailable.

[0125] In the embodiments of the present application, "access connection unavailable" may also be understood as the terminal device being out of the coverage of the base station deployed on the satellite, the base station being unable to receive the signal sent by the terminal device to the base station deployed on the satellite, or the terminal device being unable to receive the signal sent by the base station deployed on the satellite. Conversely, "access connection available" may be understood as the terminal device being within the coverage of the base station deployed on the satellite, the base station deployed on the satellite being able to receive the signal sent by the terminal device, or the terminal device being able to receive the signal sent by the base station deployed on the satellite.

[0126] In the embodiment of the present application, the unavailable feed connection can be understood as the ground station cannot receive the signal sent by the base station deployed on the satellite to the ground station, or the satellite cannot receive the signal sent by the ground station to the base station deployed on the satellite, or the base station and the core network device cannot send information (including control plane signaling, user plane data packets). Conversely, the available feed connection can be understood as the ground station can receive the signal sent by the base station deployed on the satellite, or the base station deployed on the satellite can receive the signal sent by the ground station, or the base station and the core network device can send information (including control plane signaling, user plane data packets) to each other.

[0127] For example, as shown in Figure 3, when the satellite on which the base station is deployed is at position 1, the access connection between the terminal device and the base station is available; when the satellite moves to position 2, the access connection between the terminal device and the base station and the feeding connection between the base station and the ground station are unavailable; when the satellite moves to position 3, the feeding connection between the base station and the ground station is available.

[0128] For ease of description, base stations deployed on satellites are referred to as base stations for short. That is, the base stations mentioned below specifically refer to base stations deployed on satellites.

[0129] That is to say, in the satellite network architecture of regenerative payload, the feeding connection between the base station and the ground station does not always exist, or the feeding connection between the base station and the ground station is not always available, or the connection between the terminal device and the base station does not always exist, or the access connection between the terminal device and the base station is not always available.

[0130] Furthermore, it is possible that the access connection and the feed connection are not available at the same time. At this point, the following problem arises: in the process of the terminal device initially accessing the core network, after the terminal device sends an initial access request for requesting access to the core network, the terminal device is disconnected from the current base station before receiving a reply message from the core network, that is, the terminal device is disconnected from the current base station before completing the process of accessing the core network. In the embodiment of the present application, the request for requesting access to the core network is also referred to as an initial access request, or an initial network entry request, which does not constitute a limitation of the present application.

[0131] For example, when the terminal sends an initial access request to the base station, the feeding connection between the base station and the ground station is unavailable. The base station needs to send the initial access request to the core network only when the feeding connection is available so that the core network device can determine the information to reply to the terminal device based on the first information. However, when the feeding connection is available, the access connection between the terminal device and the current base station may be unavailable.

[0132] Then, in this scenario, how to ensure that the terminal can receive the final information replied by the core network device to complete the network access of the terminal device becomes a technical problem that needs to be solved urgently.

[0133] Below, in conjunction with the accompanying drawings, the communication method provided by the present application is introduced, so that in a scenario where the terminal device is disconnected from the current base station before it is connected to the core network, the terminal device can receive a reply message sent by the core network device to the terminal, thereby completing the terminal device's access to the network.

[0134] Before describing in detail the communication method provided in the present application, the process of a terminal device accessing a core network is first explained in detail with reference to FIG4 to FIG6 . The process of a terminal device accessing a core network is also referred to as the network access process of the terminal device.

[0135] Figure 4 is a schematic diagram of a process for a conventional terminal device to access a core network according to an embodiment of the present application. The method shown in Figure 4 includes steps 410 to 440. Each step in Figure 4 is described in detail below.

[0136] Step 410: When the terminal device accesses the network, it first searches and selects a cell.

[0137] Cell search involves a terminal device detecting a base station's broadcast messages, including the physical cell identifier (PCI), master information block (MIB), and system information block / system information broadcast. The PCI is used to determine a cell, and the combination of the PCI, MIB, and system information block / system information broadcast provides the necessary information for a terminal device to reside in that cell and initiate initial access.

[0138] After the cell search is completed, the terminal device selects the PLMN cell and the terminal device achieves downlink synchronization with the cell.

[0139] Step 420: The terminal device randomly accesses.

[0140] Random access is used to achieve uplink synchronization with the cell.

[0141] For example, during this process, the base station allocates uplink resources for the terminal device to send an RRC Setup Request (RRC Setup Request), and the terminal device can initiate uplink transmission only after obtaining the uplink resources.

[0142] Step 430: After the terminal device successfully completes random access, the terminal device establishes an RRC connection with the base station.

[0143] For example, the terminal device sends an RRC Setup Request to the base station on signaling radio bearer (SRB) 0 (SRB0); after receiving the RRC Setup Request, the base station sends an RRC Setup (RRC Setup) to the terminal device, and the RRC Setup carries detailed information about the SRB1 resource configuration; after receiving the RRC Setup, the terminal device sends an RRC Setup Complete (RRC Setup Complete) to the base station to indicate that the terminal device has successfully established an RRC connection with the base station.

[0144] Among them, SRB0 does not need to be established and always exists. SRB0 is used to carry RRC signaling before the RRC connection is successfully established and is transmitted through the CCCH logical channel.

[0145] Among them, SRB1 is used to carry RRC signaling after the RRC connection is successfully established and non-access stratum (NAS) signaling before SRB2 is established, and is transmitted through the DCCH logical channel. SRB2 is used to carry NAS signaling and is transmitted through the DCCH logical channel. SRB2 has a lower priority than SRB1 and can only be established after the security mode is activated. SRB2 is established through RRC reconfiguration. NAS signaling is the signaling that transmits information between terminal devices and core network elements. The base station is only responsible for forwarding. This signaling is above the RRC layer, that is, NAS signaling can only occur after the RRC connection is successfully established.

[0146] That is, the purpose of establishing an RRC connection is to establish SRB1, and then transmit RRC signaling after the RRC connection is successfully established through SRB1.

[0147] After the RRC connection is successfully established, the terminal device and the base station will each save an RRC context, including the terminal device's identifier, such as the cell radio network temporary identifier (C-RNTI), SRB resource information, etc.

[0148] Steps 410 to 430 may also be referred to as a process of a terminal device accessing a base station. That is, the process of a terminal device accessing a base station includes: cell selection, random access, and establishment of an RRC connection.

[0149] Step 440: The terminal device establishes a connection with the core network to complete access to the core network.

[0150] For example, in 4G, the process of establishing a connection between a terminal device and a core network is shown in Figure 5. In 4G, the process of establishing a connection between a terminal device and a core network is also called an attach process.

[0151] As shown in FIG5 , the process of establishing a connection between a terminal device and a core network in 4G includes steps 510 to 570 .

[0152] Step 510: The terminal device sends an Attach Request message to the base station to request access to the core network.

[0153] Optionally, the attachment request information may include: SUCISUCI, globally unique temporary identification (GUTI), Attach type (Attach Type), and email message container (ESM message container).

[0154] Step 520: The base station forwards the Attach request information to the MME.

[0155] Optionally, when forwarding the Attach request to the MME, the selected public land mobile network (PLMN), tracking area identity (TAI) and cell global identifier (ECGI) are also indicated to the MME.

[0156] Step 530: The MME instructs the terminal device to provide the IMSI; accordingly, the terminal device provides the IMSI.

[0157] If the MME recognizes the GUTI provided by the terminal device, this step can be omitted. In other words, this step is optional.

[0158] Step 540: Authentication and authorization procedures are performed between the terminal device, base station, MME and other core network elements.

[0159] Step 550: The MME interacts with other core network elements to complete the session establishment and other processes.

[0160] Step 560: The MME sends an Attach accept message to the base station via a Downlink NAS transport message.

[0161] The attachment acceptance information is used to instruct the core network side to accept the network access request of the terminal device, or is also called the core network side allowing the terminal device to access the network.

[0162] Optionally, the Donwlink NAS transport message also includes the GUTI of the terminal device, TAI list information, and session management request information (Session Management Request).

[0163] Step 570: The base station forwards the Attach accept information to the terminal device.

[0164] The details of steps 540 to 570 can be found in the description of related technologies and will not be repeated here.

[0165] It can be understood that when the terminal device receives the Attach accept information sent by the MME, it replies with an initial access completion message to the MME through the base station. After the MME receives this message and performs actions such as configuring the bearer, the initial access process is completed.

[0166] For example, Figure 6 shows a process for establishing a connection between a key device of 5G and a core network provided by the present application. In 5G, the process for establishing a connection between a terminal device and a core network is also called a registration process.

[0167] As shown in FIG6 , the process of establishing a connection between a terminal device and a core network in 5G includes steps 610 to 670 .

[0168] Step 610: The terminal device sends a registration request (Registration Rquest) to the base station to request access to the core network.

[0169] Optionally, the registration request may include: 5G-S-TMSI, the identifier of the selected PLMN, and network slice selection assistance information (NSSAI).

[0170] Step 620: The base station forwards the registration request to the MME.

[0171] Optionally, when forwarding the Attach request to the MME, the identifier of the selected PLMN, the area information (Location information) and the cell identification (Cell identification) of the terminal device are also indicated to the MME.

[0172] Step 630: The AMF instructs the terminal device to provide the GUTI; accordingly, the terminal device provides the SUCI.

[0173] If the MME recognizes the GUTI provided by the terminal device, this step can be omitted. In other words, this step is optional.

[0174] Step 640: Authentication and authorization process is performed between the terminal device, base station, AMF and other core network elements.

[0175] Step 650: AMF and other core network elements interact to complete the terminal device signing, policy information and other processes.

[0176] Step 660: The AMF sends a registration accept message to the base station.

[0177] The registration acceptance information is used to instruct the core network side to accept the network access request of the terminal device, or is also called the core network side allowing the terminal device to access the network.

[0178] Optionally, when sending the registration acceptance information, the 5G-GUTI, registration area and allowed NSSAI of the terminal device can also be indicated to the base station.

[0179] Step 670: The base station forwards the registration acceptance information to the terminal device.

[0180] The details of steps 640 to 670 can be found in the description of related technologies and will not be repeated here.

[0181] It can be understood that when the terminal device receives the registration acceptance information sent by AMF, it replies with an initial access completion message to AMF through the base station. After AMF receives this message and performs actions such as configuring the bearer, the initial access process is completed.

[0182] The communication method provided by this application is described in detail below. This communication method can also be called a network access method for a terminal device.

[0183] Figure 7 is a schematic flow chart of a communication method provided by an embodiment of the present application. Figure 7 merely describes the method from the perspective of interaction between a terminal device, a first access network device, a second access network device, and a core network device, and does not constitute any limitation on the present application.

[0184] For example, the terminal device in Figure 7 can be replaced by a component configured in the terminal device (such as a chip, a chip system, a processor, etc.), or a logic module or software that can implement all or part of the functions of the terminal device; the first access network device can be replaced by a component configured in the first access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software that can implement all or part of the functions or software of the first access network device; the second access network device can be replaced by a component configured in the second access network device (such as a chip, a chip system, a processor, etc.), or a logic module or software that can implement all or part of the functions or software of the second access network device; the core network device can be replaced by a component configured in the core network device (such as a chip, a chip system, a processor, etc.), or a logic module or software that can implement all or part of the functions of the core network device.

[0185] The method shown in Figure 7 includes steps 701 to 705. The following describes each step of the method shown in Figure 7 in detail.

[0186] Step 701: The terminal device sends a first request to the first access network device, where the first request is used to indicate that the terminal device requests access to the core network; the first access network device receives the first request.

[0187] In this embodiment, the first request is used to instruct the terminal device to access the core network. The first request may also be called an initial access request or an initial network entry request.

[0188] Specifically, in this embodiment, the terminal device sends the first request to the first access network device when the access connection between the terminal device and the first access network device is available.

[0189] Exemplarily, the first request may be an Attach Request in a 4G communication system.

[0190] Exemplarily, the first request may be a Registration Request in a 5G communication system.

[0191] It is understood that the examples herein are merely Attach Request and Registration Request and should not constitute limitations of this application. For example, a request sent by a terminal device in a future communication system may also be considered the first request as long as the request is used by the terminal device to request access to the core network.

[0192] In addition, it is understood that in this embodiment, before the terminal device sends the first request, the terminal device needs to first establish a connection with the first access network device, that is, access the first access network device. For details on how to establish a connection with the access network device, please refer to 3GPP TS 38.331, 36.331 or the description of Figure 4, which will not be repeated here.

[0193] Step 702: The first access network device sends a first request of the terminal device to the core network device; the core network device receives the first request.

[0194] That is, after receiving the first request sent by the terminal device, the first access network device will forward the first request to the core network device, or in other words, the terminal device sends the first request to the core network device through the first access network device.

[0195] In this embodiment, when the feeding connection between the first access network device and the ground station is available, the first access network device forwards the first request of the terminal device to the core network device.

[0196] In one implementation, after the first access network device receives the first request sent by the terminal device, when the feeding connection is available, the first access network device sends the first request of the terminal device to the core network device, so that the core network device determines the terminal device requesting access to the core network.

[0197] Exemplarily, when the communication method provided in this application is applied to a 4G communication system, the core network device here may be an MME.

[0198] Exemplarily, when the communication method provided in this application is applied to a 5G communication system, the core network device here may be an AMF.

[0199] It will be understood that AMF and AMF herein are merely examples and should not constitute limitations of this application.

[0200] Step 703: The core network device sends the first information to the second access network device, where the first information is the information that the core network device replies to the terminal device based on the first request; the second access network device receives the first information.

[0201] In this embodiment, after receiving the first request from the terminal device, the core network device determines information to reply to the terminal device to help the terminal device complete the interaction process of accessing the core network. In this application, the information replied by the core network device to the terminal device is referred to as the first information.

[0202] Exemplarily, the first information may be any one of the following: information indicating acceptance of terminal device access to the core network (eg, attach accept, registration accept, etc.), authentication request, N1 message, etc., non-access stratum message (NAS message).

[0203] In this embodiment, when the feeder connection between the second access network device and the ground station is available, the core network device instructs the second access network device to reply to the terminal device with the first message, so that the reply from the core network device to the terminal device is forwarded to the terminal device via the second access network device. Alternatively, the core network device replies to the terminal device with the first message via the second access network device. Alternatively, the second access network device forwards the first message from the core network device to the terminal device. Alternatively, the second access network device stores the first message from the core network device to the terminal device.

[0204] Step 704: The terminal device establishes a connection with the second access network device.

[0205] It is understandable that when the second access network device is to reply the first message to the terminal device, it must first ensure that a connection is established between the second access network device and the terminal device. Specifically, the connection establishment mentioned here refers to the terminal device accessing the second access network device, for example, including the terminal device performing cell selection, random access, and RRC connection establishment. Only in this way can the second access network device forward the first message replied to the terminal device by the core network device to the terminal device.

[0206] Therefore, in this embodiment, the terminal device establishes a connection with the second access network device that stores the first information and sends the terminal device's identifier to the second access network device. Once the connection is established, the second access network device can determine the first information that the core network device has replied to the terminal device based on the terminal device's identifier and then forward the first information to the terminal device.

[0207] Among them, the identifier of the terminal device described in the embodiment of the present application is used to identify the terminal device that sends the first request in the initial access process. Exemplarily, the identifier of the terminal device can be an international mobile subscriber identification code (IMSI), a user permanent identifier (SUPI), a user hidden protection identifier (SUCI), a globally unique temporary identification (GUTI), a temporary mobile subscriber identity (TMSI), a cell radio network temporary identifier (C-RNTI), an inactive radio network temporary identifier (I-RNTI), etc.

[0208] It should be noted that this embodiment does not limit how the terminal device identifier sent by the terminal device to the second access network device is determined.

[0209] In a first implementation, the terminal device preconfigures or locally determines an identifier for the terminal device, and the terminal device sends the identifier to the second access network device. For example, the terminal device preconfigures an IMSI or SUPI, or locally determines a SUCI as the terminal device identifier, and then sends the identifier to the first access network device in step 701, and then sends the identifier to the second access network device in step 704. Optionally, in this first implementation, the first access network device may send the identifier of the terminal device to the core network in step 702.

[0210] In a second implementation manner, the terminal device identifier sent by the terminal device may be allocated by the first access network device.

[0211] Optionally, in an implementation scheme a) of the second implementation manner, after receiving the first request in step 701, the first access network device allocates a terminal device identifier to the terminal device and sends the terminal device identifier, for example, a C-RNTI, an I-RNTI, a combination of a C-RNTI and a RAN identifier, a combination of an I-RNTI and a RAN identifier, a TMSI, a GUTI, a dedicated identifier (which can be considered as an identifier newly added to the terminal device specifically for identifying the terminal device in the initial access process), etc. Correspondingly, the terminal device sends the terminal device identifier to the second access network device in step 704.

[0212] Optionally, in implementation scheme b) of the second implementation, when the terminal device accesses the first access network device (e.g., when establishing an RRC connection), the first access network device allocates a terminal device identifier to the terminal and sends it to the terminal device, such as a C-RNTI, an I-RNTI, a combination of a C-RNTI and a RAN identifier, or a combination of an I-RNTI and a RAN identifier. Accordingly, the terminal device sends the terminal device identifier to the second access network device in step 704.

[0213] Among them, for the second access network device, the method for determining the first information replied by the core network device based on the identifier of the terminal device may be as follows:

[0214] In a first implementation method, the second access network device determines the first information replied by the core network device based on the identifier of the terminal device sent by the terminal device, the correspondence between the identifier of the terminal device stored locally and the second identifier. The second identifier is the identifier used to identify the terminal device determined by the first access network device and the core network device when the first access network device forwards the first request to the core network device, that is, the second identifier is the identifier that identifies the terminal device between the first access network device and the core network device. Specifically, when the core network device sends the first information to the second access network device, it sends the first information and the second identifier to the second access network device together. In this way, the second access network device determines the identifier of the terminal device corresponding to the first information based on the correspondence between the second identifier and the identifier of the terminal device. Furthermore, after the terminal device sends the identifier of the terminal device, the second access network device sends the first information to the terminal device.

[0215] In the second implementation method, the core network device sends the first information and the identifier of the terminal device corresponding to the first information to the second access network device, and the second access network device stores this correspondence. In this way, after the terminal device sends the identifier of the terminal device to the second access network device, it can determine the first information corresponding to the identifier of the terminal device.

[0216] In addition, it should be noted that, in this embodiment, the terminal device only establishes a connection with the second access network device, and does not send the first request in step 701 to the second access network device.

[0217] It is to be noted here that this embodiment does not restrict how to implement the access network device that allows the terminal device to establish a connection, and the way in which the core network device determines that the access network device that stores and forwards the first information replied by the core network device is the second access network device.

[0218] In the first implementation mode, the terminal device and the core network device may agree in advance: after receiving the first request, the core network device sends the first information to the first access network device that forwards the first request; accordingly, the terminal device re-establishes a connection with the first access network device that receives the first request and sends the terminal device's identifier. For example, the terminal device determines that the broadcast comes from the first access network device based on the identifier of the first access network device in the received broadcast message, and then establishes a connection with the first access network device, wherein the identifier of the first access network device may be locally configured by the terminal device or received from the first access network device in advance. Alternatively, the terminal device establishes a connection with the access network device that sent the broadcast message received by the terminal device after the timer expires, based on a locally configured timer. According to the timer, it can be ensured that this access network device is the first access network device. Specifically, this timer can be determined by the terminal device based on ephemeris information.

[0219] It is understandable that because the core network device stores the first information replied to the terminal device in the first access network device, and the terminal device establishes a connection with the first access network device and the first access network device sends the terminal device's identifier, the second access network device, after establishing a connection with the terminal device, can determine based on the terminal device's identifier that the first information corresponding to the terminal device is stored, and thus send the first information to the terminal device, helping the terminal device complete the process of accessing the core network. In addition, it is understandable that in this first implementation, the second access network device is the first access network device, or in other words, the second access network device and the first access network device are the same access network device.

[0220] In a second implementation, the first access network device determines the second access network device, instructs the terminal device to establish a connection with the second access network device, and also indicates the second access network device to the core network device. For example, based on the ephemeris information, the first access network device determines as the second access network device the access network device that can most quickly reach the terminal device and that can quickly obtain the first information from the core network device.

[0221] Among them, ephemeris information is information about the motion patterns of satellites, such as the satellite's orbital parameters, angular velocity, speed, and other information. Based on this information, communication equipment can calculate the position of the satellite in orbit at each moment. Ephemeris information can be expressed as a simple correspondence, such as the satellite position information corresponding to each moment / time period. Ephemeris information can also be expressed as a satellite coverage map, such as satellite coverage availability information. The satellite coverage map can divide the earth's surface into multiple grid points and display the grid points covered and not covered by the satellite at each moment. For example, the orbital cycle of a satellite orbiting the earth is one hour with an accuracy of minutes. Each minute, there is a satellite coverage map corresponding to the satellite. Some grid points in the map are bright and some are dark. The bright grid points represent the grid points that will be covered at the corresponding moment in each cycle of the satellite.

[0222] It should be noted that the ephemeris information involved in this application includes but is not limited to traditional ephemeris information, satellite map information, and gateway deployment information. Among them, traditional ephemeris information includes but is not limited to orbital parameters, or parameters such as the satellite's position calculated based on the orbital parameters. It is understandable that traditional ephemeris information can be used to calculate, predict, depict, or track the time, position, speed, and other states of the satellite's flight. For example, traditional ephemeris information can be 17 bytes of information to represent position (78 bits) and speed (54 bits), or traditional ephemeris information can be 18 bytes of information to represent orbital parameters (such as semi-major axis, range, eccentricity, perigee angle, etc.). Satellite map information can be the range covered by the satellite on the map at each moment. The specific form, content, and name of the ephemeris information are not limited in this application, and reference can be made to the definition of ephemeris information in existing protocols. For example, the ephemeris information in this application can also be referred to as satellite coverage availability information.

[0223] It should be noted that this embodiment does not limit how the first access network device indicates to the terminal device the second access network device to establish a connection.

[0224] For example, in one indication method, a first access network device determines a first duration, where the value of the first duration satisfies: the second access network device can cover the terminal device after the first duration and has obtained first information from the core network device. The first access network device then sends second information to the terminal device to indicate the first duration, and the first access network device sends an identifier of the second access network device to the core network device so that the core network device sends the first information to the second access network device, thereby helping the terminal device complete the process of accessing the core network.

[0225] For example, the first access network device can determine the first duration based on the ephemeris information and at least one of the following information: the position of the satellite on which the first access network device is deployed, the position of the terminal device, and the current time. It can be understood that the first duration can be considered as the timing for triggering the terminal device to establish a connection with the second access network device. Therefore, the first duration is also called the access timer of the terminal device. This embodiment does not limit the specific content of the second information that specifically indicates the first duration. For example, the content of the second information is the determined first duration; for another example, the content of the second information is a timer timer, and the first duration is indicated by the timer timer; or, the content of the second information can be the time when the terminal device establishes the connection. Accordingly, after receiving the time, the terminal device determines the first duration in combination with the current time.

[0226] It is understandable that in this manner, the broadcast message received by the terminal device after the first duration is a broadcast message from the second access network device. Furthermore, the access network device to which the terminal device accesses and sends its identifier is the second access network device. The core network device has already sent the first information to the second access network device. Therefore, after the terminal device establishes a connection with the second access network device, the second access network device determines the stored first information corresponding to the terminal device based on the identifier of the terminal device and sends the first information to the terminal device, thereby completing the process of the terminal device accessing the core network.

[0227] Optionally, in the method of indicating the first duration, if the second access network device determined by the first access network device is the same as the first access network device, the first access network device may only indicate the first duration to the terminal device without indicating the second access network device to the core network device; accordingly, the core network device forwards the first information through the first access network device. Optionally, when the first access network device and the second access network device are the same, because the terminal device will only establish a connection with the first access network device, the terminal device identifier can be RAN-specific (i.e., it does not need to be globally unique, but only needs to be unique within each RAN).

[0228] For example, in another indication method, after the first access network device determines the second access network device, it sends the first identifier for identifying the second access network device to the terminal device to instruct the terminal device to access the second access network device, and sends the first identifier to the core network device to instruct the core network device to determine the second access network device to receive (or store) the first information.

[0229] Exemplarily, the first identifier used to identify the second access network device can be: the physical cell identifier (PCI) of the cell included in the second access network device, the E-UTRAN cell global identifier (ECGI) / NR cell global identifier (NCGI) (including eNB / gNB ID), and global RAN node ID in the system information block (SIB1) message.

[0230] It is understandable that in this manner, the terminal device determines that the broadcast message is from the second access network device based on the first identifier in the received broadcast message, then establishes a connection with the second access network device and sends the terminal device's identifier to the second access network device. The core network device has already sent the first message in reply to the terminal device to the second access network device. Therefore, after the second access network device establishes a connection with the terminal device, it determines the stored first information corresponding to the terminal device based on the terminal device's identifier and sends the first information to the terminal device, thereby completing the process of the terminal device accessing the core network.

[0231] Optionally, in the manner of indicating the identifier of the second access network device, the terminal device may continue to detect, or so-called continuously detect, until a broadcast message including the first identifier is detected. Alternatively, the terminal device may determine the time period during which the terminal device will be covered by the second access network device next time (which may also be considered as the time period during which the terminal device and the second access network device will have a next available access connection). For example, the terminal device determines the time period during which the terminal device will be covered by the second access network device next time based on the ephemeris information, and then the terminal device detects broadcast messages including the first identifier only within this time period.

[0232] Optionally, in the method of indicating the identifier of the second access network device, if the second access network device determined by the first access network device is the same as the first access network device, then the first access network device may also only send the first identifier to the terminal device instead of sending the first identifier to the core network device; accordingly, the core network device sends the first information to the first access network device.

[0233] In a third implementation, the terminal device detects only the broadcast message from the first access network device and establishes a connection only with the first access network device. The first access network device sends its identifier to the core network device, which then determines a second access network device to receive (or store) the first information. If the second access network device determined by the core network device is different from the first access network device, the core network device sends the first information, the terminal device's identifier, and the identifier of the first access network device to the second access network device. Accordingly, the second access network device also carries the identifier of the first access network device in its broadcast message.

[0234] It can be understood that in this third implementation method, for the terminal device, when receiving a broadcast message including the identifier of the first access network device, one situation is that the broadcast message including the identifier of the first access network device comes from the first access network device, and the other situation is that it comes from the second access network device. At this time, if it comes from the second access network device, then when the terminal device establishes a connection with the second access network device and sends the identifier of the terminal device, the second access network device can determine the corresponding first information based on the identifier of the terminal device, and then send the first information to the terminal device to help the terminal device complete the process of accessing the core network.

[0235] It should be understood that in this third implementation method, the identifier of the terminal device must be globally unique, because different access network devices are required to send messages to the terminal device. If it is not globally unique, the identifier of the terminal device determined between different access network devices and different terminal devices may be repeated.

[0236] Optionally, in this third implementation, the second access network device may continuously broadcast the identifier of the first access network device. Alternatively, the second access network device may broadcast the identifier of the first access network device only during the time period covering the terminal device. For example, the first access network device sends the location information of the terminal device to the core network device, and then the core network device sends the location information of the terminal device to the second access network device. The second access network device determines the time period covering the terminal device based on the ephemeris information and the location of the terminal device, and then carries the identifier of the first access network device in the broadcast message when broadcasting during the time period. Alternatively, the core network device directly determines the time period covering the terminal device based on the ephemeris information and the terminal device, and then sends the time period to the second access network device. Accordingly, the second access network device carries the identifier of the first access network device when broadcasting messages during the time period.

[0237] In a fourth implementation, instead of receiving an instruction from the first access network device, the terminal device and the core network device agree to use the same algorithm to determine the same second access network device.

[0238] For example, the terminal device and the core network device both determine the second access network device based on the ephemeris information and at least one of the following information: the location of the terminal device and the current time. Exemplarily, the terminal device and the core network device both determine the access network device that can cover the terminal device the fastest and obtain the first information from the core network device the fastest as the second access network device. In this way, after the terminal device establishes a connection with the second access network device and sends the terminal device's identifier to the second access network device, the second access network device determines the stored first information corresponding to the terminal device based on the terminal device's identifier and sends the first information to the terminal device to complete the process of the terminal device accessing the core network.

[0239] It is understandable that, in this manner, the second access network device determined by the terminal device and the core network device may be the same access network device as the first access network device, or may be a different access network device from the first access network device. Furthermore, it is understandable that this fourth implementation differs from the first implementation: the first implementation can be considered a protocol-specified method, meaning that neither the terminal device nor the core network device performs any internal process to determine the second access network device. In this fourth implementation, both the terminal device and the core network device determine the second access network device based on the same algorithm.

[0240] In the fifth implementation method, the terminal device determines the second access network device and sends the first identifier used to identify the second access network device to the core network device through the first access network device; accordingly, after the core network receives the first identifier, it sends the first information to the second access network device.

[0241] For example, the terminal device determines the second access network device based on the ephemeris information and at least one of the following information: the location of the terminal device and the current time. Exemplarily, the terminal device determines the access network device that can most quickly cover the terminal device and obtain the first information from the core network device as the second access network device. The terminal device then sends the second access network device identifier to the core network device via the first access network device to indicate to the core network device the second access network device to which the terminal device will establish a connection. The core network device sends the first information in reply to the terminal device to the second access network device, thereby ensuring that after the terminal device establishes a connection with the second access network device, the first information in reply from the core network device stored in the second access network device is obtained, thereby ensuring that the terminal device completes the process of accessing the core network.

[0242] It is understandable that in this manner, the second access network device determined by the terminal device may be the same access network device as the first access network device, or may not be the same access network device. When the first access network device and the second access network device are not the same access network device, the determined access network device needs to be indicated to the core network device so that the access network device with which the terminal device establishes a connection and the access network device with which the first information sent by the core network device is received are the same. Optionally, when the first access network device and the second access network device are the same access network device, the terminal device may also indicate the second access network device to be connected to without indicating to the core network device through the first access network device. For example, the core network device sends the first information to the first access network device without any indication.

[0243] Optionally, in a fifth implementation, the terminal device may continuously detect, or the terminal device may determine the time period when it will next be covered by the second access network device, and then detect the broadcast message including the first identifier only during that time period. This section can refer to the description in the second implementation and will not be repeated here.

[0244] In a sixth implementation, the core network device determines the second access network device. For example, based on ephemeris information, the core network device determines the access network device that can most quickly reach the terminal device and that can most quickly obtain the first information from the core network device as the second access network device. The core network device then does not indicate the second access network device to the terminal device. Accordingly, upon receiving any broadcast message, the terminal device establishes a connection with the access network device from which the broadcast message originated and sends the terminal device's identifier. Specifically, this also includes the second access network device. Because the second access network device stores the first information that the core network device responded to the terminal device, after establishing a connection with the terminal device, the second access network device determines the first information corresponding to the terminal device's identifier based on the terminal device's identifier, and then sends the first information to the terminal device, helping the terminal device complete the core network access process. If the access network device connected to the terminal device is not the second access network device, the following approach can be implemented: If the terminal device does not receive the first information sent by the access network device within a period of time, the terminal device automatically releases the connection with the access network device. Alternatively, when the terminal device establishes a connection with the access network device, it sends an indication message to the access network device, instructing the access network device to send the information that the core network device replies to the terminal device. If the access network device determines, based on the identifier of the terminal device, that the first information that the core network device replies to the terminal device is not stored, it releases the connection with the terminal device or instructs the terminal device to release the connection.

[0245] Step 705: The second access network device sends the first information to the terminal device, where the first information is the information that the core network device replies to the terminal device based on the first request; the terminal device receives the first information.

[0246] Exemplarily, the first information may be any one of the following: information indicating acceptance of terminal device access to the core network (eg, attach accept, registration accept, etc.), authentication request, N1 message, etc., non-access stratum message (NAS message).

[0247] As described in step 704, since the second access network device stores the first information that the core network device replies to the terminal device, and the second access network device can determine the identifier of the terminal device corresponding to the first information, after the terminal device establishes a connection with the second access network device and sends the identifier of the terminal device to the second access network device, the second access network device can determine that there is the first information corresponding to the terminal device based on the identifier of the terminal device, and thereby send the first information to the terminal device to help the terminal device complete the process of accessing the core network.

[0248] It can be seen that in the embodiment of Figure 7, after the terminal device sends the first request to the first access network device, even if the terminal device disconnects from the first access network device, since the terminal device establishes a connection with the second access network device that stores the first information and sends the terminal device identifier to the second access network device, the second access network device can determine the first information that the stored core network device replies to the terminal device based on the terminal device identifier, and then send the first information to the terminal device, thereby also helping the terminal device complete the process of accessing the core network.

[0249] The communication method shown in FIG. 7 will be described in detail below with reference to FIG. 8 to FIG. 15 .

[0250] Specifically, in the embodiment of Figure 8 , the first access network device determines that the access network device to which the terminal device initiates the connection and the access network device that receives the first information sent by the core network device are both the first access network device. That is, in the embodiment of Figure 8 , the second access network device is the same as the first access network device.

[0251] The following is a detailed description with reference to Figure 8. Figure 8 is a flow chart of a communication method provided by an embodiment of the present application. The method 800 shown in Figure 8 includes steps 801 to 810. The following describes each step in the method 800 in detail.

[0252] Step 801: A connection is established between a terminal device and a first access network device.

[0253] It should be understood that before sending the first request to the first access network device, the terminal device must first establish a connection with the first access network device. For example, the terminal device performs cell selection and random access before establishing a connection with the first access network device. The process for establishing a connection between the terminal device and the first access network device can refer to the process for a terminal device accessing a base station described above.

[0254] After the terminal device establishes a connection with the first access network device, the terminal device can send RRC layer information and part of the NAS information.

[0255] Step 802: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0256] It can be understood that the first request in this application is the information of the NAS layer.

[0257] The details of this step may refer to the description of S701 in the embodiment of FIG. 7 , and will not be repeated here.

[0258] Step 803: The first access network device determines a first duration according to the ephemeris information.

[0259] Specifically, after receiving the first request, the first access network device will determine the first duration. Specifically, the first duration can be considered as the timing for triggering the terminal device to establish a connection with the first access network device. Therefore, the first duration determined by the first access network device is also called the access timer of the terminal device determined by the first access network device. For example, if the first duration is 30 seconds, the terminal device will establish a connection with the first access network device 30 seconds after receiving the first duration indicated by the first access network device.

[0260] In this embodiment, when the first access network device determines the first duration, the first duration needs to meet the following requirements: after the first duration, the first access network device can cover the terminal device, and the first access network device has obtained (or stored) the first information that the core network device replies to the terminal device. In other words, the first duration needs to meet the following requirements: after the first duration, the access connection between the first access network device and the terminal device will be available again, and within the first duration, the feeder connection between the first access network device and the ground station will be available to enable the storage of the first information sent by the core network device in reply to the terminal device. For the description of the first information, please refer to the description in the embodiment of Figure 7, which will not be repeated here.

[0261] Step 804: The first access network device sends second information to the terminal device, where the second information is used to indicate the first duration; the terminal device receives the second information.

[0262] Step 805: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0263] In this embodiment, the terminal device identifier is also referred to as a negotiation ID. It is understood that the negotiation ID is used to identify the terminal device that sends the first request during the initial access process, ensuring that the core network device's response to the terminal device, such as the initial access acceptance message and authentication request, is delivered to the terminal device.

[0264] This step can occur before or after any of steps 801 to 804, and the negotiation ID can also be sent during any of steps 801, 802, or 804. For example, when establishing a connection in step 801, the first access network device sends a C-RNTI to the terminal device, and this C-RNTI serves as the negotiation ID. Alternatively, in step 802, the terminal device sends an IMSI to the first access network device, and this IMSI serves as the negotiation ID.

[0265] In the embodiment of FIG. 8 , the negotiation ID may be RAN specific (ie, it does not need to be globally unique, but only needs to be unique within each RAN), because the terminal device will only establish a connection with the first access network device.

[0266] It should be noted that, in this embodiment, step 805 is optional. That is, the process of the terminal device and the first access network device negotiating the negotiation ID is optional. For example, if the terminal device also carries the terminal device identifier when sending the first request, this step may not be performed.

[0267] Step 806: When the feeder connection between the first access network device and the core network device is available, the first access network device indicates the first request of the terminal device to the core network device.

[0268] Optionally, the first access network device may send an identifier of the first access network device to the core network device to indicate to the core network device that the first access network device is the access network device that receives the information replied by the core network device to the terminal device.

[0269] Step 807: The core network device instructs the first access network device to reply to the first information of the terminal device.

[0270] In this embodiment, upon receiving a first request from a terminal device forwarded by a first access network device for accessing the core network, the core network device determines first information to be fed back to the terminal device. For example, the first information may be any of the following: attach accept, registration accept, authentication request, N1 message, etc.

[0271] It can be understood that the core network device instructs the first access network device to reply to the first information of the terminal device, specifically means that the core network device instructs the first access network device to reply to the first information of the terminal device when the feeding connection between the first access network device and the ground station is available.

[0272] Specifically, the core network device sends the first information and the identifier for identifying the terminal device determined by the first access network device and the core network device to the first access network device, which can be considered as the second identifier in the embodiment of Figure 7, for example, it can also be expressed as identifier 2. Accordingly, the first access network device determines the negotiation ID corresponding to the first information replied by the core network device based on the correspondence between the negotiation ID and identifier 2.

[0273] In some embodiments, the identifier 2 is the same as the negotiation ID, and in other embodiments, the identifier 2 is different from the negotiation ID.

[0274] Step 808: After the first duration ends, the terminal device establishes a connection with the first access network device.

[0275] Specifically, this step includes: after the first time period ends, the terminal device initiates random access to the first access network device; the terminal device establishes an RRC connection with the first access network device. More specifically, in the present application, when the terminal device establishes a connection with the first access network device, the information sent to the first access network device (i.e., RRC layer information) will not include information for requesting access to the core network, that is, it will not include the first information. In addition, in this embodiment, when the terminal device re-establishes a connection with the first access network device, it sends the negotiation ID previously determined with the first access network device to the first access network device.

[0276] Optionally, after the first time period ends, the terminal device initiates random access to the first access network device and establishes an RRC connection with the first access network device. This can also be replaced by: the terminal device initiates RRC resume to the first access network device. The difference is that: in the case of initiating random access, the terminal device and the first access network device will not retain the RRC context, re-initiate random access and establish a new RRC context. If RRC resume is initiated, the first access network device and the terminal device need to retain the RRC context.

[0277] Optionally, the terminal device may further send fifth information to the first access network device, where the fifth information is used to instruct the first access network device to feed back information that the core network device should reply to the terminal device based on the first information. That is, it can be considered that the terminal device displays information that instructs the first access network device to feed back information that the core network device should feed back to the terminal device based on the first information.

[0278] In this embodiment, during the process of establishing a connection between the terminal device and the first access network device, a negotiation ID is sent to the first access network device.

[0279] Step 809: The first access network device determines and stores the first information replied by the core network device to the terminal device based on the negotiation ID of the terminal device.

[0280] Specifically, after the first access network device obtains the negotiation ID of the terminal device, the first access network device determines the first information that the core network device replies to the terminal device based on the correspondence between the negotiation ID and identifier 2.

[0281] Step 810: The first access network device sends the first information to the terminal device.

[0282] It can be seen that in the communication method provided in this embodiment, the first access network device indicates the first duration to the terminal device, triggering the terminal device to re-establish a connection with the first access network device after the first duration ends. Furthermore, the first access network device determines and stores the first information replied by the core network device to the terminal device based on the negotiation ID of the terminal device, and then forwards the first information to the terminal device, thereby helping the terminal device complete the process of accessing the core network.

[0283] FIG9 is a flow chart of a communication method 900 provided in another embodiment of the present application. In the embodiment of FIG9 , it is still the first access network device that determines the access network device to which the terminal device initiates the connection and the access network device to which the first information sent by the core network device is received. However, the difference from the embodiment of FIG8 is that the access network device determined by the first access network device to which the terminal device initiates the connection and the access network device to which the first information sent by the core network device is received are not the first access network device. That is, in the embodiment of FIG9 , the second access network device is different from the first access network device.

[0284] The following is a detailed description with reference to Figure 9. Figure 9 is a flow chart of a communication method provided by an embodiment of the present application. The method 900 shown in Figure 9 includes steps 901 to 910. The following describes each step in the method 900 in detail.

[0285] Step 901: A connection is established between a terminal device and a first access network device.

[0286] Step 902: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0287] Step 903: The first access network device determines a first duration according to the ephemeris information.

[0288] In this embodiment, when the first access network device determines the first duration, the first duration needs to satisfy the following conditions: after the first duration, the second access network device can cover the terminal device, and the second access network device has obtained (or stored) the first message sent by the core network device in reply to the terminal device. In other words, the first duration needs to satisfy the following conditions: after the first duration, the access connection between the second access network device and the terminal device will be available again, and within the second duration, the feeder connection between the second access network device and the ground station will be available to enable storage of the first message sent by the core network device in reply to the terminal device.

[0289] Step 904: The first access network device sends second information to the terminal device, where the second information is used to indicate the first duration; the terminal device receives the second information.

[0290] This step may refer to the content of S804 in the embodiment of FIG8 , and will not be described in detail here.

[0291] Step 905: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0292] In this embodiment, the identifier determined by the terminal device and the first access network device is also referred to as a negotiation ID. The content of the negotiation ID can be referred to the description in step 802 in the embodiment of FIG8 , and will not be repeated here.

[0293] The content of this step can refer to the content of S805 in the embodiment of Figure 8, and will not be repeated here.

[0294] Step 906: When the feeding connection between the first access network device and the core network device is available, the first access network device indicates the first request of the terminal device to the core network device.

[0295] In this embodiment, when the first access network device sends the first request to the core network device, it also indicates the negotiation ID to the core network device.

[0296] In this embodiment, the first access network device also sends the identifier of the second access network device to the core network device, instructing the core network device to send the first message replied to the terminal device to the second access network device. In other words, in this embodiment, the first access network device sends the identifier of the access network device used to receive the first message to the core network device.

[0297] Step 907: The core network device instructs the second access network device to reply to the first information of the terminal device.

[0298] It can be understood that the core network device instructs the second access network device to reply to the first information of the terminal device, specifically refers to the core network device instructing the second access network device to reply to the first information of the terminal device when the feeding connection between the second access network device and the ground station is available.

[0299] In this embodiment, the core network device sends the first information and the negotiation ID in step 902 to the second access network device, so that the second access network device determines the identifier (negotiation ID) of the terminal device corresponding to the first information replied by the core network device.

[0300] Step 908: After the first duration ends, the terminal device establishes a connection with the second access network device.

[0301] Specifically, this step includes: the terminal device initiates random access to the second access network device; the terminal device establishes an RRC connection with the second access network device.

[0302] In addition, in this embodiment, when the terminal device establishes a connection with the second access network device, the terminal device sends the negotiation ID previously determined with the first access network device to the first access network device.

[0303] Optionally, the terminal device may further send fifth information to the first access network device, where the fifth information is used to instruct the second access network device to feed back information that the core network device responded to the terminal based on the first information. That is, it can be considered that the terminal device displays an instruction to instruct the second access network device to feed back information that the core network device fed back to the terminal device based on the first information.

[0304] Step 909: The second access network device uses the negotiation ID of the terminal device to determine the first information that the core network device replies to the terminal device.

[0305] It can be understood that in step 907, the core network device indicates to the second access network device the first information to be replied to the terminal device and the negotiation ID corresponding to the first information; therefore, when the terminal device establishes a connection with the second access network device and sends the negotiation ID, the second access network device determines and stores the first information replied by the core network device to the terminal device based on the negotiation ID.

[0306] Step 910: The second access network device sends the first information to the terminal device.

[0307] It can be seen that in the communication method provided in this embodiment, the first access network device indicates the first duration to the terminal device, so that the terminal device establishes a connection with the second access network device after the first duration ends. Furthermore, the second access network device determines the first information that the core network device replies to the terminal device based on the negotiation ID of the terminal device, and then forwards the first information to the terminal device, thereby helping the terminal device complete the process of accessing the core network.

[0308] Optionally, in the embodiment shown in FIG9 , the access network device may not send the identifier of the second access network device to the core network device in step 906; accordingly,

[0309] Step 907 is replaced by: the core network device instructs the first access network device to reply to the first information of the terminal device;

[0310] Step 909 is replaced with: the second access network device obtains, from the first access network device, the first message replied by the core network device to the terminal device based on the negotiation ID of the terminal device. For example, the second access network device sends the negotiation ID of the terminal device to multiple access network devices, including the first access network device. After receiving the negotiation ID of the terminal device, the first access network device determines that it has stored the first message replied by the core network device to the terminal device and sends the first message to the second access network device.

[0311] Figure 10 is another schematic diagram illustrating a communication method 1000 according to an embodiment of the present application. In the embodiment of Figure 10 , a terminal device stores an identifier of a first access network device, and a core network device sends a first message in reply to the terminal device to the first access network device. Upon receiving a broadcast message from the first access network device, the terminal device establishes a connection with the first access network device. In other words, in the embodiment of Figure 10 , the second access network device is the same as the first access network device.

[0312] As shown in FIG10 , the embodiment of FIG10 includes:

[0313] Step 1001: A connection is established between a terminal device and a first access network device.

[0314] Step 1002: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0315] Step 1003: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0316] In this embodiment, the identifier is also called a negotiation ID.

[0317] The details of step 1001 and step 1003 can be found in the description of the corresponding parts in the embodiment of FIG8 , and will not be repeated here.

[0318] Step 1004: The terminal device stores the identifier of the first access network device.

[0319] For example, the first access network device may display an instruction for the terminal device to store the identifier of the first access network device. It is understood that displaying an instruction for the terminal device to store the identifier of the first access network device may also be considered as displaying an instruction for the terminal device to establish a connection with the first access network device; alternatively, the terminal device may store the identifier of the first access network device by default. It is understood that the identifier of the first access network device may be considered as the first identifier in the embodiment of FIG. 3 .

[0320] Exemplarily, the identifier of the first access network device can be the PCI (physical cell identifier) ​​of the cell included in the first access network device, the ECGI (E-UTRAN cell global identifier, E-UTRAN cell global identifier) / NCGI (NR cell global identifier, NR cell global identifier) ​​(including eNB / gNB ID), and the global RAN node ID in the SIB1 (System Information Block) message.

[0321] In this embodiment, the identifier of the first access network device is used to identify the first access network device, and can be sent to the terminal device in a broadcast message or in an RRC message.

[0322] Step 1005: When the feeder connection between the first access network device and the core network device is available, the first access network device indicates the first request of the terminal device to the core network device.

[0323] Step 1006: The core network device instructs the first access network device to reply to the first information of the terminal device.

[0324] For details of step 1005 and step 1006, please refer to the contents of step 806 and step 807 in the embodiment of FIG8 , which will not be repeated here.

[0325] Step 1007: When the terminal device receives (or detects) the broadcast message including the identifier of the first access network device, it establishes a connection with the first access network device.

[0326] Specifically, this step includes: when the terminal device receives a broadcast message including the identifier of the first access network device, the terminal device initiates random access to the first access network device; and the terminal device establishes an RRC connection with the first access network device.

[0327] It is understood that when an access network device broadcasts, the broadcast message will carry an identifier for identifying the access network device. Therefore, in this embodiment, when a terminal device receives a broadcast message, it can determine whether the access network device from which the currently received broadcast message came is the first access network device based on the identifier of the broadcasting access network device.

[0328] It should be noted that this embodiment does not limit the manner in which the terminal device receives the broadcast message including the identifier of the first access network device.

[0329] For example, in one implementation, the terminal device may continue to detect, or continuously detect, until a broadcast message including the identifier of the first access network device is detected. In other words, in this embodiment, after sending the first request to the first access network device, the terminal device continues to detect broadcast messages including the identifier of the first access network device, even within the NAS timer.

[0330] The NAS timer is the time a terminal device can wait after sending a NAS message. If a reply is received within this time period, the process can proceed normally. If the time period is exceeded, the terminal device will assume that the sent NAS message is lost or erroneous and may resend the NAS message. For example, if the NAS timer of the first message expires, the terminal device may resend the first message. However, during the NAS timer period, the terminal device will wait for a reply and will not initiate new messages or perform actions such as cell selection or random access.

[0331] For example, in another implementation, the terminal device may determine the next time period covered by the first access network device (which may also be considered the time period during which the terminal device and the first access network device are next available for connection). For example, the terminal device determines the next time period covered by the first access network device based on ephemeris information, and then the terminal device detects broadcast messages including the identifier of the first access network device only during this time period. It is understandable that this approach can reduce power consumption of the terminal device.

[0332] Optionally, as shown in Figure 10, the first access network device may execute step 00: the first access network device sends at least one of the following to the terminal device: ephemeris information, or the time period for the next coverage of the terminal device, or the time interval, where the time interval is specifically the interval between the time when the first access network device next covers the terminal device and the time when the terminal device is currently covered; accordingly, the terminal device is based on the indication of the first access network device and the time period during which the terminal device is covered by the first access network device next time.

[0333] Optionally, step 1107 may be replaced by: upon receiving a broadcast message including the identifier of the first access network device, the terminal device initiates an RRC resume to the first access network device, so that the terminal device can re-establish a connection with the first access network device. Similarly, during detection, continuous monitoring may be performed, or detection may be performed within a target time period.

[0334] It is understandable that when a broadcast message including the identifier of the first access network device is detected, it indicates that the access connection between the terminal device and the first access network device is available. In other words, information sent by the terminal device can be received by the first access network device and signals sent by the first access network device can be received by the terminal device.

[0335] In this embodiment, when the terminal device detects a broadcast message that does not include the identifier of the first access network device, the terminal device establishes a connection.

[0336] In this embodiment, when the terminal device establishes a connection with the first access network device, it also sends a negotiation ID to the first access network device.

[0337] Step 1008: The first access network device determines and stores the first information fed back by the core network device to the terminal device based on the negotiation ID of the terminal device.

[0338] Step 1009: The first access network device sends first information to the terminal device.

[0339] It can be seen that in the communication method provided in this embodiment, the terminal device will detect the broadcast message including the identification of the first access network device, and then establish a connection with the first access network device again when the broadcast message including the identification of the first access network device is detected. The first access network device determines that the first information replied by the core network device to the terminal device is stored based on the negotiation ID of the terminal device, and then forwards the first information to the terminal device, thereby helping the terminal device complete the process of accessing the core network.

[0340] Figure 11 is another schematic diagram illustrating another process of the communication method provided by an embodiment of the present application. The embodiment of Figure 11 differs from the embodiment of Figure 10 in that the terminal device stores the identifier of an access network device different from the first access network device, i.e., the terminal device establishes an RRC connection with a device other than the first access network device. In other words, in this embodiment, the second access network device is different from the first access network device.

[0341] As shown in FIG11 , the embodiment of FIG11 includes:

[0342] Step 1101: A connection is established between a terminal device and a first access network device.

[0343] Step 1102: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0344] Step 1103: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0345] In this embodiment, the identifier is also called a negotiation ID.

[0346] Step 1104: The first access network device sends the identifier of the second access network device to the terminal device.

[0347] The identifier of the second access network device is used to identify the second access network device, and the identifier of the second access network device can also be considered as the first identifier in the embodiment of FIG. 3 .

[0348] In this embodiment, the second access network device is specifically an access network device determined by the first access network device to send the first information to the terminal device.

[0349] Optionally, the second access network device is the access network device that is determined by the first access network device based on the ephemeris information to be able to cover the terminal device fastest and to obtain the first information from the core network device fastest.

[0350] Exemplarily, the first access network device may determine the second access network device through inter-satellite link negotiation with at least one other access network device.

[0351] Step 1105: The terminal device stores the identifier of the second access network device.

[0352] Step 1106: When the feeding connection between the first access network device and the core network device is available, the first access network device indicates the first request of the terminal device to the core network device.

[0353] In this embodiment, when the first access network device sends the first request to the core network device, it also indicates the negotiation ID of the terminal device to the core network device.

[0354] In this embodiment, the first access network device also sends the identifier of the second access network device to the core network device, instructing the core network device to send the first message replied to the terminal device to the second access network device. In other words, in this embodiment, the first access network device sends the identifier of the access network device used to receive the first message to the core network device.

[0355] Step 1107: The core network device instructs the second access network device to reply to the first information of the terminal device.

[0356] It can be understood that the core network device instructs the second access network device to reply to the first information of the terminal device, specifically refers to the core network device instructing the second access network device to reply to the first information of the terminal device when the feeding connection between the second access network device and the ground station is available.

[0357] In this embodiment, when the core network device sends the first information to the second access network device, it also sends the negotiation ID of the terminal device, so that the second access network device can determine the correspondence between the negotiation ID and the first information, so that the second access network device can determine the terminal device corresponding to the first information replied by the core network device.

[0358] Step 1108: When the terminal device detects the broadcast message including the identifier of the second access network device, it establishes a connection with the second access network device.

[0359] Specifically, this step includes: the terminal device detects a broadcast message including an identifier of the second access network device and initiates random access; the terminal device establishes an RRC connection with the second access network device.

[0360] For example, in one implementation, the terminal device may be allowed to perform detection all the time, or continuous detection, until a broadcast message including the identifier of the second access network device is detected.

[0361] For example, in another implementation, the terminal device can determine the time period that will be covered by the second access network device (which can also be considered as the time period during which the terminal device and the second access network device are available for the next access connection). For example, the terminal device determines the time period that will be covered by the second access network device based on the ephemeris information, and then the terminal device only detects the broadcast message including the identification of the second access network device within this time period.

[0362] Optionally, as shown in Figure 11, the first access network device may execute: the first access network device sends at least one of the following to the terminal device: ephemeris information, the time period when the second access network device will cover the terminal device next time, or a time interval, where the time interval is specifically the interval between the time when the second access network device will cover the terminal device and the time when the terminal device is currently covered; accordingly, the terminal device is based on the indication of the first access network device during the time period covered by the second access network device next time.

[0363] It is understandable that when a broadcast message containing the identifier of the second access network device is detected, it indicates that the access connection between the terminal device and the second access network device is available. In other words, information sent by the terminal device can be received by the second access network device and signals sent by the second access network device can be received by the terminal device.

[0364] In this embodiment, when the terminal device detects a broadcast message that does not include the identifier of the second access network device, the terminal device does not initiate random access or RRC resume.

[0365] In this embodiment, when the terminal device establishes a connection with the second access network device, the terminal device also sends a negotiation ID to the second access network device.

[0366] Step 1109: The second access network device determines that the first information fed back by the core network device to the terminal device is stored based on the negotiation ID of the terminal device.

[0367] Step 1110: The second access network device sends the first information to the terminal device.

[0368] It can be seen that in the communication method provided in this embodiment, the terminal device will detect a broadcast message including the identifier of the second access network device, and then when a broadcast message including the identifier of the second access network device is detected, it will establish a connection with the second access network device and send a negotiation ID to the second access network device, so that the second access network device sends the first information that the core network device replies to the terminal device based on the negotiation ID.

[0369] Summarizing the embodiments shown in Figures 8 to 11 above, it can be seen that in the embodiments shown in Figures 8 and 9, the first access network device indicates the first duration to the terminal device, thereby triggering the terminal device to establish a connection with the access network device that stores the first information, thereby obtaining the first information to help the terminal device access the network. In contrast, in the embodiments shown in Figures 10 and 11, the identifier of the access network device that stores and forwards the first information is used by the terminal device to trigger the terminal device to obtain the first information from the access network device that stores the first information, thereby helping the terminal device access the network.

[0370] Optionally, the terminal device may not store the identifier of the access network device that forwards the first information, and the first access network device may not indicate to the terminal device the first duration for triggering the terminal device to establish a connection. Instead, as long as the terminal device detects any broadcast message, it will establish a connection with the access network device that sent the broadcast message. At this time, it can be understood that for the access network device that stores the first information corresponding to the terminal device, the first information is fed back to the terminal device; otherwise, the terminal device releases the RRC connection. Below, a detailed embodiment of this method is described in conjunction with Figure 12.

[0371] In this embodiment, for ease of description, the first access network device is represented as access network device 1, the access network device used to store the first information is represented as access network device 2, and the access network device that does not store the first information is represented as access network device 3, also referred to as the third access network device. It will be understood that access network device 2 is the second access network device described in FIG. 3 of this application.

[0372] FIG12 is another flow diagram of a communication method provided by an embodiment of the present application. As shown in FIG12 , method 1200 includes:

[0373] Step 02: Base station 1 broadcasts ephemeris information.

[0374] This step is optional.

[0375] Step 1201: A connection is established between the terminal device and access network device 1.

[0376] Step 1202: The terminal device sends a first request to the access network device 1; the access network device 1 receives the first request.

[0377] Step 1203: The terminal device and access network device 1 determine the identifier of the terminal device used in the initial access process.

[0378] In this embodiment, the identifier is also called a negotiation ID.

[0379] For details of this step, please refer to the description in step 805 and will not be repeated here.

[0380] Step 1204: When the feeder connection between the access network device 1 and the core network device is available, the access network device 1 indicates the first request of the terminal device to the core network device.

[0381] Step 1205: The core network device determines the access network device 2 to forward the first message in reply to the terminal device.

[0382] In this embodiment, the access network device 2 determined by the core network device may be one or more access network devices.

[0383] It should be noted that this embodiment does not limit the access network device 2 on how the core network device specifically forwards the first information.

[0384] Optionally, the core network device may be determined based on the ephemeris information. For example, the core network device determines the access network device that can most quickly cover the terminal device and can most quickly obtain the first information from the core network device based on the ephemeris information as access network device 2.

[0385] Optionally, the core network device may send the first information to any one or more base stations. In this manner, the core network device does not perform the step of determining the access network device 2, but makes an arbitrary selection.

[0386] Step 1206: The core network device instructs access network device 2 to reply to the first information of the terminal device.

[0387] It can be understood that the core network device instructs the access network device 2 to reply to the first information of the terminal device, specifically means that the core network device instructs the access network device 2 to reply to the first information of the terminal device when the feeding connection between the second access network device and the ground station is available.

[0388] Specifically, in this embodiment, when the core network device sends the first information to the access network device 2, it also indicates the negotiation ID, so that the access network device 2 can determine the terminal device corresponding to the first information replied by the core network device.

[0389] Step 1207: The terminal device detects the broadcast message of access network device 3.

[0390] Step 1208: The terminal device establishes a connection with access network device 3.

[0391] Specifically, this step includes: the terminal device initiates random access to the access network device 3; step 11072: the terminal device establishes a connection with the access network device 3.

[0392] Step 1209: Release the connection with access network device 3.

[0393] Optionally, this step can be implemented in two ways:

[0394] As shown in FIG12 , in implementation method (a), if the terminal device does not receive the first information sent by the access network device 3 within the second time period, the terminal device automatically releases the RRC connection with the access network device 3 .

[0395] As shown in Figure 2, in implementation method (b), after the terminal device establishes a connection with the access network device 3, it can send a third message to the access network device 3, and the third message is used to instruct the access network device 3 to send the information that the core network device replies to the terminal device; accordingly, after the access network device 3 receives the third message, it determines according to the negotiation ID of the terminal device that there is no reply information of the core network device to the terminal device, and then sends a fourth message to the terminal device, and the fourth information is used to instruct the terminal device to release the connection with the access network device 3; the terminal device releases the RRC connection with the access network device 3.

[0396] Step 1210: The terminal device detects the broadcast message of access network device 2.

[0397] Step 1211: Establish a connection with access network device 2.

[0398] Specifically, this step includes: the terminal device initiates random access to the access network device 2; the terminal device establishes an RRC connection with the access network device 2.

[0399] In addition, in this embodiment, when the terminal device establishes a connection with the access network device 2 , the terminal device sends the negotiation ID previously determined with the access network device 1 to the access network device 2 .

[0400] Step 1212: Based on the negotiation ID, the access network device 2 determines that the first information replied by the core network device to the terminal device is stored, and sends the first information to the terminal device.

[0401] Optionally, the terminal device may further send a fifth message to access network device 2, where the fifth message is used to instruct access network device 2 to feed back information that the core network device has replied to the terminal based on the first message. That is, it can be considered that the terminal device displays an instruction to instruct access network device 2 to feed back information that the core network device has replied to the terminal device based on the first message.

[0402] As can be seen, in the embodiment shown in FIG12 , as soon as the terminal device detects a broadcast message, it establishes a connection with the access network device that sent the broadcast message. At this time, for the access network device that has established a connection with the terminal device, if the first information fed back by the core network device to the terminal device is stored, the first information is sent to the terminal device to help the terminal device access the network. Otherwise, if the first information is not stored, no message is sent to the terminal device or the terminal device is instructed to release the RRC connection, so as to inform the terminal device that the current access network device does not store the first information sent by the core network device to the terminal device.

[0403] It should be noted that the embodiment of FIG12 is merely described by taking one access network device 2 determined by the core network device as an example. It is understandable that when the core network device determines that there are multiple access network devices 2 to send the first information, the core network device will send the first information and the negotiation ID to each of the multiple access network devices 2.

[0404] Optionally, the core network device can configure a timer for the one or more access network devices 2; accordingly, for the multiple access network devices, when the timer expires, the stored first information is deleted. Exemplarily, when determining the timer, the core network device can determine it based on the time of the access network device 2 that covers the terminal device the fastest. For example, the access network device 2 in the embodiment of Figure 12 will definitely cover the UE after 100us. At this time, the timer can be set to 100us. In this way, while ensuring that the terminal device can receive the information replied by the core network device, it can also ensure that all access network devices that have stored the first information delete the first information as quickly as possible.

[0405] Figure 13 is a flow chart of a communication method provided by another embodiment of the present application. In the embodiment of Figure 13, the terminal device detects only broadcast messages that include the identifier of the first access network device by default; then the core network device independently determines the second access network device that stores and forwards the first message to the terminal device, and sends the identifier of the first access network device to the second access network device, so that the second access network device also broadcasts the identifier of the first access network device when broadcasting the message. Below, a detailed embodiment of this method is described by taking the second access network device and the first access network device as an example, where the second access network device is not the same access network device as the first access network device.

[0406] As shown in FIG. 13 , the method 1300 of the embodiment of FIG. 13 includes:

[0407] Step 1301: A connection is established between a terminal device and a first access network device.

[0408] Optionally, the first access network device may further send ephemeris information to the terminal device. For example, the first access network device broadcasts the ephemeris information, or sends the ephemeris information to the terminal device via an RRC message after establishing a connection.

[0409] Step 1302: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0410] Step 1303: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0411] In this embodiment, the identifier is also called a negotiation ID.

[0412] Specifically, in this embodiment, the negotiation ID must be globally unique because different access network devices are required to send messages to the terminal device. If it is not globally unique, the IDs negotiated between different access network devices and different terminal devices may be repeated.

[0413] Step 1304: When the feeding connection between the first access network device and the core network device is available, the first access network device indicates the first request of the terminal device to the core network device.

[0414] In this embodiment, when the first access network device sends the first request to the core network device, it also indicates the negotiation ID and the identifier of the first access network device.

[0415] Optionally, the first access network device may also send the location information of the terminal device to the core network device.

[0416] Step 1305: The core network device sends the first information, the negotiation ID, and the identifier of the first access network device to the second access network device.

[0417] It should be noted that this embodiment does not limit how the core network device determines the second access network device.

[0418] For example, the second access network device is an access network device that can obtain the first information faster and cover the terminal device fastest, determined based on the ephemeris information.

[0419] In this embodiment, the core network device sends the identifier of the first access network device to the second access network device. This is primarily for the second access network device to broadcast the identifier of the first access network device during broadcasting. That is, when the second access network device broadcasts, the identifiers of the access network devices broadcast include the identifier of the first access network device and the identifier of the second access network device.

[0420] Step 1306: The second access network device sends a broadcast message, which includes the identifier of the first access network device; the terminal device detects the broadcast message including the identifier of the first access network device.

[0421] It should be understood that access network devices capable of broadcasting the identifier of the first access network device include the first access network device and the second access network device. However, the first information is not stored in the first access network device, while the first information is stored in the second access network device. Therefore, in this embodiment, when a terminal device detects a broadcast message broadcasting the identifier of the first access network device, if the broadcast message is from the first access network device, the terminal device will not receive the first information. In this case, the terminal device can release the connection. Specifically, the method for releasing the connection can be referred to in step 1208 of the embodiment shown in Figure 12, and will not be further described.

[0422] Optionally, in this embodiment, the second access network device may include the identifier of the first access network device in the broadcast message only during the period of coverage of the terminal device. The implementation method thereof can be referred to the detailed description of the third implementation method in step 704 in the embodiment of FIG.

[0423] In this embodiment, it is assumed that the broadcast message including the identifier of the first access network device comes from the second access network device. For the case where the second access network device is not the second access network device, please refer to the description in step 1306, which will not be repeated here.

[0424] Step 1307: The terminal device establishes a connection with the second access network device.

[0425] Similarly, it includes: the terminal device initiates random access to the second access network device; the terminal device establishes an RRC connection with the second access network device.

[0426] In this embodiment, during the process of establishing a connection between the terminal device and the second access network device, a negotiation ID is sent to the second access network device.

[0427] Step 1308: The second access network device determines that the first information replied by the core network device to the terminal device is stored based on the negotiation ID, and sends the first information to the terminal device.

[0428] Since the second access network device stores the correspondence between the negotiation ID and the first information, the second access network device can determine the stored first information based on the negotiation ID sent by the terminal device.

[0429] Step 1309: The second access network device sends the first information to the terminal device.

[0430] It can be seen that in the communication method provided in this embodiment, on the terminal device side, the terminal device will detect the broadcast message including the identifier of the first access network device, and then, upon detecting the broadcast message including the identifier of the first access network device, establish a connection with the access network device from which the broadcast message came. Correspondingly, on the core network device side, the identifier of the first access network device will be sent to the second access network device, so that the second access network device broadcasts the identifier of the first access network device when broadcasting. In this way, when the terminal device detects the broadcast message of the second access network device and establishes a connection with the second access network device, the second access network device can determine that the first information replied to the terminal device by the core network device is stored, thereby continuing to complete the network access process of the terminal device.

[0431] FIG14 is a flow chart of a communication method provided by another embodiment of the present application. As shown in FIG14 , the embodiment of FIG14 includes:

[0432] Step 1401: A connection is established between a terminal device and a first access network device.

[0433] Step 1402: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0434] Step 1403: The terminal device and the first access network device determine the identifier of the terminal device used in the initial access process.

[0435] Step 1404: The terminal device determines the second access network device to initiate the connection.

[0436] Alternatively, from another perspective, the terminal device determines the second access network device that stores the first information replied by the core network device to the terminal device.

[0437] Step 1405: When the feeder connection between the first access network device and the core network device is available, the first access network device sends the negotiation ID of the terminal device and the first request to the core network device.

[0438] Step 1406: The core network device determines and stores the second access network device that replies to the first information to the terminal device.

[0439] Alternatively, from another perspective, the terminal device determines the second access network device to which the terminal device initiates a connection.

[0440] In this embodiment, the terminal device and the core network device need to ensure that the second access network device they determine is the same. Therefore, in one implementation, for example, the same rule can be preset in the terminal device and the core network device to ensure that the second access network device they determine is the same.

[0441] Exemplarily, the rule may be: determining the second access network device as the access network device that can most quickly retrieve the first information from the core network device to reply to the terminal device and that can quickly cover the terminal device's location. In some implementations, the terminal device and the core network device determine the second access network device based on ephemeris information and at least one of the following information: the terminal device's location and the current time.

[0442] Step 1407: The core network device sends the first information and the negotiation ID of the terminal device to the second access network device.

[0443] Step 1408: The terminal device detects a broadcast message including the second access network device.

[0444] Step 1409: The terminal device establishes a connection with the second access network device.

[0445] In this embodiment, during the process of establishing a connection between the terminal device and the second access network device, the negotiation ID is sent to the second access network device.

[0446] Similarly, it includes: the terminal device initiates random access to the second access network device; the terminal device establishes an RRC connection with the second access network device.

[0447] Step 1410: The second access network device determines that the first information replied by the core network device to the terminal device is stored based on the negotiation ID, and sends the first information to the terminal device.

[0448] Optionally, the terminal device may instruct the access network device 2 to send the first message replied by the core network device to the terminal device.

[0449] Step 1411: The second access network device sends the first information to the terminal device.

[0450] It can be seen that in the method provided in this embodiment, through preset rules, the terminal device and the core network device each determine the same second access network device, so that the access network device to which the terminal device establishes a connection is the access network device that stores the first information replied by the core network device to the terminal device, thereby continuing to complete the network access process of the terminal device.

[0451] FIG15 is a flow chart of a communication method provided by another embodiment of the present application. As shown in FIG15 , the embodiment of FIG15 includes:

[0452] Step 1501: A connection is established between a terminal device and a first access network device.

[0453] Step 1502: The terminal device sends a first request to the first access network device; the first access network device receives the first request.

[0454] Step 1503: The terminal device and the first access network device determine an identifier of the terminal device used in the initial access process.

[0455] Step 1504: The terminal device determines the second access network device to initiate the connection.

[0456] Alternatively, from another perspective, the terminal device determines the second access network device that stores the first information replied by the core network device to the terminal device.

[0457] Step 1505: The terminal device sends the identifier of the second access network device to the first access network device.

[0458] It can be understood that the identifier of the second access network device can be considered as the first identifier in the embodiment of FIG. 7 .

[0459] Specifically, in this embodiment, the main purpose of the terminal device sending the identifier of the second access network device to the first access network device is to forward the identifier of the second access network device to the core network device through the first access network device, so that the core network device can determine the access network device to which the terminal device establishes a connection, or from another perspective, the core network device determines the second access network device that stores the first information replied to the terminal device.

[0460] Step 1506: When the feeder connection between the first access network device and the core network device is available, the first access network device sends the negotiation ID of the terminal device, the first request, and the identifier of the second access network device to the core network device.

[0461] Alternatively, from another perspective, the terminal device determines the second access network device to which the terminal device initiates a connection.

[0462] Exemplarily, the terminal device determines as the second access network device the access network device that can most quickly retrieve the first information from the core network device to reply to the terminal device and that can most quickly cover the terminal device's location. In some implementations, the terminal device determines the second access network device based on ephemeris information and at least one of the following information: the terminal device's location and the current time.

[0463] Step 1507: The core network device sends the first information and the negotiation ID of the terminal device to the second access network device.

[0464] Step 1508: The terminal device detects a broadcast message including the second access network device.

[0465] Step 1509: The terminal device establishes a connection with the second access network device.

[0466] Similarly, it includes: the terminal device initiates random access to the second access network device; the terminal device establishes an RRC connection with the second access network device.

[0467] In this embodiment, when the terminal device establishes a connection with the second access network device, the negotiation ID is sent to the second access network device.

[0468] Step 1510: The second access network device determines that the first information replied by the core network device to the terminal device is stored based on the negotiation ID, and sends the first information to the terminal device.

[0469] Optionally, the terminal device may instruct the second access network device to send the first message replied by the core network device to the terminal device.

[0470] Step 1511: The second access network device sends the first information to the terminal device.

[0471] It can be seen that in the method provided in this embodiment, the second access network device to establish a connection is determined by the terminal device, or from another perspective, the terminal device determines the second access network device that stores the first information, and then the terminal device notifies the first access network device of the identifier of the second access network device, which notifies the core network device, thereby ensuring that the core network device sends the first information replied to the terminal device to the second access network device that the terminal device is about to establish a connection with, thereby helping the terminal device to continue to complete the terminal device's network access process.

[0472] The communication method of an embodiment of the present application is described in detail above in conjunction with Figures 7 to 15. The communication device provided in the present application will be described in detail below in conjunction with Figures 16 and 17.

[0473] FIG16 is a schematic structural diagram of a communication device provided by an embodiment of the present application. Specifically, as shown in FIG16 , the device 1600 includes: a receiving module 1601 , a sending module 1602 , and a processing module 1603 .

[0474] In the first embodiment, the apparatus 1600 may be applied to a terminal device.

[0475] Specifically, the sending module 1602 is used to send a first request to the first access network device, where the first request is used to indicate that the terminal device requests access to the core network; the processing module 1603 is used to establish a connection with the second access network device and send the identifier of the terminal device to the second access network device; the receiving module 1601 is used to receive first information from the second access network device, where the first information is the information that the core network replies to the terminal device based on the first request, and the first information corresponds to the identifier of the terminal device.

[0476] In a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0477] In one possible implementation, the receiving module 1601 is used to receive second information sent by the first access network device, where the second information is used to indicate a first duration; the processing module 1603 is also used to establish a connection with the second access network device after the first duration.

[0478] In a possible implementation manner, the first duration is determined by the first access network device based on ephemeris information.

[0479] In a possible implementation, the processing module 1602 is further used to: obtain a first identifier, where the first identifier is used to identify a second access network device; and establish a connection with the second access network device when the first identifier is received from the second access network device.

[0480] In a possible implementation, the receiving module 1601 is further configured to: receive a first identifier from a first access network device.

[0481] In a possible implementation, the processing module 1602 is further configured to: determine the first identifier according to ephemeris information.

[0482] In a possible implementation, the sending module 1602 is further configured to send the first identifier to the first access network device.

[0483] In a possible implementation, the processing module 1602 is further used to: establish a connection with a third access network device; and release the connection with the third access network device if the first information sent by the third access network device is not received within a second time period.

[0484] In one possible implementation, the sending module 1602 is further used to send third information to the third access network device, where the third information is used to instruct the third access network device to send information that the core network device replies to the terminal device; the receiving module 1601 is further used to receive fourth information sent by the third access network device in response to the third information, where the fourth information is used to instruct the terminal device to release the connection with the third access network device; the processing module 1602 is also used to: release the connection with the third access network device.

[0485] In a possible implementation, the sending module 1602 is further used to send fifth information to the second access network device, where the fifth information is used to instruct the second access network device to send information that the core network device replies to the terminal device.

[0486] In the second embodiment, the communication apparatus may be applied to a first access network device.

[0487] Specifically, the receiving module 1601 is used to receive a first request, where the first request is used to indicate that the terminal device requests access to the core network; the sending module 1602 is used to send second information to the terminal device, where the second information is used to indicate a first duration, wherein the terminal device establishes a connection with a second access network device after the first duration ends, and the second access network device is used to store the first information that the core network device replies to the terminal device based on the first request; the sending module 1602 is also used to send a first request to the core network device.

[0488] In a possible implementation, when the second access network device and the first access network device are different access network devices, the sending module 1602 is further configured to send an identifier of the second access network device to the core network device.

[0489] In a possible implementation manner, the first duration is determined by the first access network device based on ephemeris information.

[0490] In one possible implementation, when the second access network device and the first access network device are the same access network device, the receiving module 1601 is also used to receive fifth information from the terminal device, and the fifth information is used to instruct the second access network device to send information that the core network device replies to the terminal device.

[0491] In a third embodiment, the communication apparatus may be applied to a first access network device.

[0492] Specifically, the receiving module 1601 is used to receive a first request, which is used to indicate that the terminal device requests to access the core network; the sending module 1602 is used to send a first identifier to the terminal, which is used to identify a second access network device, and the second access network device is used to store the first information that the core network device replies to the terminal device based on the first request; the sending module 1602 is also used to send the first request to the core network device.

[0493] In a possible implementation, the sending module 1602 is further used to: send a first identifier to the core network device, where the first identifier is used by the core network device to determine to send the first information to the terminal device through the second access network device.

[0494] In a possible implementation manner, the second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

[0495] In one possible implementation, when the second access network device and the first access network device are the same access network device, the receiving module 1601 is further used to receive fifth information from the terminal device, and the fifth information is used to indicate information that the core network device sends to reply to the terminal device.

[0496] In a fourth embodiment, the communication apparatus may be applied to a second access network device.

[0497] Specifically, the receiving module 1601 is used to receive the first information from the core network device, where the first information is the information that the core network replies to the terminal device based on the first request, where the first request is used to indicate that the terminal device requests to access the core network, and the first information corresponds to the first terminal device identifier; the sending module 1602 is used to receive the first terminal device identifier and send the first information to the terminal device that sent the first terminal device identifier.

[0498] In a possible implementation, the first terminal device identifier is sent by the core network device to the second access network device.

[0499] Figure 17 is a schematic structural diagram of a communication device provided in another embodiment of the present application. The device shown in Figure 17 can be used to execute the method described in any of the above embodiments.

[0500] As shown in Figure 17, the apparatus 1700 of this embodiment includes a memory 1701 and a processor 1702. In one implementation, the apparatus 1700 further includes a communication interface 1703 and a bus 1704. The memory 1701, the processor 1702, and the communication interface 1703 are communicatively connected to each other via the bus 1704.

[0501] The memory 1701 may be a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1701 may store a program. When the program stored in the memory 1701 is executed by the processor 1702, the processor 1702 is configured to perform the steps of the method shown in Figures 7 to 15.

[0502] The processor 1702 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits to execute relevant programs to implement the methods shown in Figures 7 to 15 of the present application.

[0503] The processor 1702 may also be an integrated circuit chip having signal processing capabilities. In the implementation process, each step of the method of FIG. 7 to FIG. 15 of the embodiment of the present application may be completed by an integrated logic circuit of hardware in the processor 1702 or by instructions in the form of software.

[0504] The processor 1702 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The processor 1702 may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or a conventional processor.

[0505] The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1001, and the processor 1702 reads the information in the memory 1701 and, in combination with its hardware, completes the functions required to be performed by the units included in the device of the present application. For example, the various steps / functions of the embodiments shown in Figures 7 to 15 can be executed.

[0506] The communication interface 1703 may use, but is not limited to, a transceiver or other transceiver device to implement communication between the apparatus 1700 and other devices or a communication network.

[0507] The bus 1704 may include a path for transmitting information between various components of the device 1700 (eg, the memory 1701 , the processor 1702 , and the communication interface 1703 ).

[0508] It should be understood that the apparatus 1700 shown in the embodiment of the present application can be an electronic device, or a chip configured in an electronic device. The apparatus 1700 can be deployed in a terminal device, or can also be deployed in a network device.

[0509] The present application also provides a computer program product, which includes: a computer program (also referred to as code, or instructions). When the computer program is run, it can implement the steps executed by the terminal, verification network element or storage network element in any one of the embodiments shown in Figures 7 to 15.

[0510] The present application also provides a computer-readable storage medium storing a computer program (also referred to as code or instructions). When the computer program is executed, the steps performed by the terminal, verification network element, or storage network element in any of the embodiments shown in Figures 7 to 15 can be implemented.

[0511] An embodiment of the present application provides a communication system, which includes the terminal device, the first access network device, the second access network device and the core network device as described above.

[0512] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be an available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0513] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0514] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0515] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute a limitation on the implementation process of the embodiments of the present application.

[0516] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0517] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0518] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0519] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0520] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0521] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

Claims

1. A communication method, characterized in that, Applied to a terminal device, including: Sending a first request to a first access network device, where the first request is used to indicate that the terminal device requests to access the core network; Establishing a connection with a second access network device and sending an identifier of the terminal device to the second access network device; Receiving first information from the second access network device, where the first information is information replied by the core network to the terminal device based on the first request, and the first information corresponds to the identifier of the terminal device.

2. The method according to claim 1, characterized in that, The second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

3. The method according to claim 1 or 2, characterized in that, The method further includes: Receiving second information sent by the first access network device, where the second information is used to indicate a first duration; The establishing a connection with the second access network device includes: After the first duration, establishing a connection with the second access network device.

4. The method according to claim 3, characterized in that, The first duration is determined by the first access network device based on ephemeris information.

5. The method according to claim 1 or 2, characterized in that, The method further includes: Obtaining a first identifier, where the first identifier is used to identify the second access network device; The establishing a connection with the second access network device includes: When receiving the first identifier from the second access network device, establishing a connection with the second access network device.

6. The method according to claim 5, wherein The obtaining the first identifier includes: Receiving the first identifier from the first access network device.

7. The method according to claim 5, wherein The obtaining the first identifier includes: Determining the first identifier according to ephemeris information.

8. The method according to claim 7, wherein The method further includes: Sending the first identifier to the first access network device.

9. The method according to any one of claims 1 to 8, characterized in that, The method further includes: Establishing a connection with a third access network device; If the first information sent by the third access network device is not received within a second duration, releasing the connection with the third access network device.

10. The method according to claim 9, characterized in that The method further includes: Sending third information to the third access network device, where the third information is used to indicate that the third access network device sends information replied by the core network device to the terminal device; Receiving fourth information sent by the third access network device in response to the third information, where the fourth information is used to indicate that the terminal device releases the connection with the third access network device; Releasing the connection with the third access network device.

11. The method according to any one of claims 1 to 10, characterized in that, The method further includes: Sending fifth information to the second access network device, where the fifth information is used to indicate that the second access network device sends information replied by the core network device to the terminal device.

12. A communication method, characterized in that, Applied to a first access network device, including: Receiving a first request, where the first request is used to indicate that a terminal device requests to access the core network; Sending second information to the terminal device, where the second information is used to indicate a first duration, where the terminal device establishes a connection with a second access network device after the first duration ends, and the second access network device is used to store first information replied by the core network device to the terminal device; Sending the first request to the core network device.

13. The method according to claim 12, wherein The second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

14. The method according to claim 12 or 13, characterized in that, When the second access network device is different from the first access network device, the method further includes: Sending an identifier of the second access network device to the core network device.

15. The method according to any one of claims 12 to 14, characterized in that, The first duration is determined by the first access network device based on ephemeris information.

16. The method according to claim 13 or 15, characterized in that, When the second access network device and the first access network device are the same access network device, the method further includes: Receiving fifth information from the terminal device, where the fifth information is used to indicate information sent by the core network device in response to the terminal device.

17. A communication method, characterized in that, Applied to a first access network device, it includes: Receiving a first request, where the first request is used to indicate that a terminal device requests access to the core network; Sending a first identifier to the terminal, where the first identifier is used to identify a second access network device, and the second access network device is used to store first information sent by the core network device in response to the first request to the terminal device; Sending the first request to the core network device.

18. The method according to claim 17, wherein The method further includes: Sending the first identifier to the core network device, where the first identifier is used for the core network device to determine to send the first information to the terminal device through the second access network device.

19. The method according to claim 17 or 18, characterized in that, The second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

20. The method according to claim 19, wherein When the second access network device and the first access network device are the same access network device, the method further includes: Receiving fifth information from the terminal device, where the fifth information is used to indicate information sent by the core network device in response to the terminal device.

21. A communication method, characterized in that, Applied to a second access network device, it includes: Receiving first information from the core network device, where the first information is information sent by the core network in response to a first request to a terminal device, the first request is used to indicate that the terminal device requests access to the core network, and the first information corresponds to a first terminal device identifier; Upon receiving the first terminal device identifier, sending the first information to the terminal device that sent the first terminal device identifier.

22. The method according to claim 21, wherein The first terminal device identifier is sent by the core network device to the second access network device.

23. A communication device, characterized in that, It includes: A processor, The processor is used to cause the communication device to implement the method according to any one of claims 1 to 11 by executing a computer program and / or through logic circuits.

24. A communication device, characterized in that, It includes: A processor, The processor is used to cause the communication device to implement the method according to any one of claims 12 to 16 by executing a computer program and / or through logic circuits.

25. A communication device, characterized in that, It includes: A processor, The processor is used to cause the communication device to implement the method according to any one of claims 17 to 20 by executing a computer program and / or through logic circuits.

26. A communication system, characterized in that, It includes the communication device according to claim 20 or claim 21 or claim 22.

27. A computer-readable medium, characterized in that, The computer-readable medium stores program code for computer execution, and the program code includes instructions for executing the method according to any one of claims 1 to 11 or 12 to 16 or 17 to 20.

28. A computer program product, characterized in that, The computer program product includes computer program code which, when run on a computer, causes the computer to implement the method described in any one of claims 1 to 11 or 12 to 16 or 17 to 20.

29. A chip, characterized in that, It includes at least one processor and a communication interface. The communication interface and the at least one processor are interconnected by a line. The at least one processor is configured to run a computer program or instructions to perform the communication method described in any one of claims 1 to 11 or 12 to 16 or 17 to 20.

30. A communication method, characterized in that, Applied to a core network device, it includes: Receiving a first request sent by a first access network device, where the first request is used to indicate that a terminal device requests to access the core network; Sending first information to a second access network device, where the first information is the information replied by the core network device to the terminal device based on the first request; Wherein, the second access network device is determined based on any one of the following methods: the first access network device indicates to the core network device, the terminal device indicates to the core network device, or the core network device determines based on ephemeris information.

31. The method according to claim 30, wherein The method further includes: Instructing the second access network device to delete the stored first information after a third time period.

32. The method according to claim 30 or 31, characterized in that, The second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

33. The method according to any one of claims 30 to 32, characterized in that, The method further includes: indicating the location of the terminal device to the second access network device.

34. A communication method, characterized in that, Applied to a terminal device, it includes: Sending a first request to a first access network device, where the first request is used to indicate that the terminal device requests to access the core network; Obtaining indication information for indicating that the terminal device accesses a second access network device from the first access network device or locally; Establishing a connection with the second access network device according to the indication information and sending the identifier of the terminal device to the second access network device; Receiving first information from the second access network device, where the first information is the information replied by the core network to the terminal device based on the first request, and the first information corresponds to the identifier of the terminal device.

35. The method according to claim 34, wherein The second access network device and the first access network device are the same access network device, or the second access network device and the first access network device are different access network devices.

36. The method according to claim 34 or 35, characterized in that, The indication information is a first time period obtained from the first access network device; The establishing a connection with the second access network device according to the indication information includes: Establishing a connection with the second access network device after the first time period.

37. The method according to claim 34 or 35, characterized in that, The indication information is a first identifier sent by the first access network device, where the first identifier is used to identify the second access network device that stores the first information replied by the core network device.

38. The method according to claim 34 or 35, characterized in that, The indication information is a first identifier determined locally by the terminal device according to ephemeris information, where the first identifier is used to identify the second access network device that stores the first information replied by the core network device.

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