Communication method, apparatus, device, and readable storage medium

Abstract

The application provides a communication method, device and equipment and a readable storage medium, which are applied to the field of communication. The method comprises the following steps: receiving first indication information, wherein the first indication information indicates a plurality of candidate satellites corresponding to a terminal device, and the candidate satellite is a satellite configured by a core network device for the terminal device. That is, by enabling an access network device to obtain a plurality of candidate satellites, the completeness and richness of the information received by the access network device are improved, subsequent decision of the access network device is facilitated, the efficiency of service transmission is improved, and user experience is improved.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a communication method, apparatus, device, and readable storage medium. Background Technology

[0002] With the continuous development of communication technology, satellite communication technology has become increasingly mature. For example, in non-terrestrial network (NTN) systems, global communication coverage is achieved through non-terrestrial infrastructure such as satellites and high-altitude platforms.

[0003] In related technologies, during or after the execution of a non-access stratum (NAS) procedure, the core network equipment will configure multiple candidate satellites for the terminal device. The NAS procedure includes an attachment procedure or a tracking area update procedure. The terminal device uses the candidate satellites to help determine the target cell that can currently provide services.

[0004] However, the limited information received by access network devices can affect the efficiency of terminal devices when performing cell handover, cell reselection, or cell selection. Summary of the Invention

[0005] This application provides a communication method, apparatus, device, and readable storage medium that improves the completeness and richness of information received by the access network device by enabling the access network device to acquire multiple candidate satellites, facilitating subsequent decision-making by the access network device, improving the efficiency of service transmission, and enhancing user experience.

[0006] In a first aspect, a method for cell handover is provided, which is applied to an access network device, wherein the access network device is an access network device in a non-terrestrial network (NTN), and the method includes: receiving first indication information, wherein the first indication information indicates multiple candidate satellites corresponding to a terminal device, wherein the candidate satellites are satellites configured by a core network device for the terminal device, and the candidate satellites are used to provide the cell for the terminal device to access; wherein the first indication information comes from the terminal device; or, the first indication information comes from a core network element in the core network device.

[0007] In the technical solution of this application, in the NTN system, the access network device receives the first instruction information and determines that the core network device will configure multiple candidate satellites corresponding to the terminal device. This improves the completeness and richness of the information obtained by the access network device, facilitates the access network device to guide the terminal device to determine the target cell to be accessed, and can improve the efficiency of service transmission and enhance the user experience.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates multiple satellite identifiers, and each of the multiple satellite identifiers corresponds to a multiple candidate satellite. By using the above method, carrying the satellite identifiers used to indicate candidate satellites in the first indication information for transmission can reduce the data content in the first indication information, thereby improving transmission performance.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates multiple indices, which are used to indicate satellite identifiers, and each of the multiple indices corresponds to a multiple satellite identifier. By transmitting the first indication information carrying both the satellite identifier and the corresponding index, the completeness of the data related to candidate satellites in the first indication information can be improved. Furthermore, during the reading of the first indication information, the satellite identifier corresponding to the candidate satellite can be quickly determined by reading the index, thus improving data analysis efficiency.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information includes multiple first fields; wherein the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether the information of the (i+1)-th candidate satellite exists in the first indication information. The information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, where i is a positive integer. By carrying first fields in the first indication information using the above method, the access network device can determine whether the information of the next candidate satellite in the first indication information exists through the first fields when acquiring the current candidate satellite, thereby improving data analysis efficiency.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, when the i-th first field takes the first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite; when the i-th first field takes the second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite. By defining different values ​​for the first field to explicitly express whether a next candidate satellite exists, the access network device can promptly grasp the existence of the next candidate satellite while reading the information of the current candidate satellite, thereby improving data analysis efficiency.

[0012] In conjunction with the first aspect, in certain implementations of the first aspect, the first indication information includes at least one of the following: a second field, used to indicate the number of candidate satellites in the first indication information; and a third field, used to indicate the length of the data packet corresponding to the first indication information, the data packet length being used to determine the number of candidate satellites. By carrying either the second or third field in the first indication information using the above method to determine the number of candidate satellites, the access network device can further determine the number of candidate satellites in addition to identifying them, thereby improving data integrity and content richness.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates the second field, and the satellite identifier corresponds to the first number of bits in the first indication information; the method further includes: determining the satellite identifiers corresponding to multiple candidate satellites in the first indication information based on the first number of bits and the second field corresponding to multiple satellite identifiers respectively. By using the above method to determine the satellite identifiers corresponding to candidate satellites using the number of bits and the second field corresponding to the satellite identifiers, the richness and completeness of the data reading results are improved, further enhancing the accuracy of determining the cells corresponding to candidate satellites.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates the third field, and the satellite identifier corresponds to the second bit number in the first indication information; the above method further includes: determining the number of candidate satellites in the first indication information based on the second bit number and the third field corresponding to multiple satellite identifiers respectively. By using the above method to determine the number of candidate satellites using the bit number corresponding to the satellite identifier and the third field, the richness and completeness of the data reading results are improved, further enhancing the accuracy of determining the cell corresponding to the candidate satellite.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates the third field, and the first indication information also includes a fourth field. The fourth field is used to indicate that the first indication information includes other information besides the satellite identifier. The fourth field corresponds to the third number of bits in the first indication information, and the satellite identifier corresponds to the fourth number of bits in the first indication information. The method further includes: subtracting the third number of bits from the data packet length corresponding to the fourth field to obtain a first length; and determining the number of candidate satellites in the first indication information based on the fourth number of bits corresponding to multiple satellite identifiers and the first length. By subtracting the number of bits of other data from the data packet length using the above method, the number of candidate satellites is calculated based on the number of bits corresponding to the satellite identifiers and the remaining length, avoiding the influence of other data in the first indication information on the determination of the number, and improving the accuracy of the satellite count.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: sending a first message to the terminal device, the first message being used to request the terminal device to send first indication information; or, sending a second message to the core network element, the second message being used to request the core network element to send the first indication information. By sending the first indication information to the access network device only after receiving the request message, the response speed of the communication system can be improved, and the reliability of the communication system can be enhanced.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information is sent by the terminal device; the first indication information is carried in any of the following: a medium access control control element (MAC CE); or a radio resource control (RRC) message; or a first measurement report. By using the above method to send the first indication information using different message formats, the message transmission rate can be optimized by selecting an appropriate message format.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information is carried in the first measurement report, which includes the measurement results of the first cell, and the first cell belongs to the cell corresponding to the candidate satellite; the first indication information is used to indicate the candidate satellite corresponding to the first cell. By using the above method, based on the measurement report message indicating multiple cells corresponding to the terminal device, the cell corresponding to the candidate satellite is determined, which can increase the probability that the access network device assists the terminal cell in selecting the cell corresponding to the candidate satellite for access, thereby improving the decision-making effect of the auxiliary decision.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell. By using the above method, and based on the measurement report message indicating multiple cells corresponding to the terminal device, the satellite identifier of the candidate satellite corresponding to each cell can be indicated, thereby reducing the amount of information transmitted and improving information transmission efficiency.

[0020] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: receiving a second measurement report sent by the terminal device, the second measurement report including the measurement results of the second cell, and the second measurement report including second indication information, the second indication information being used to indicate whether the second cell belongs to the cell corresponding to the candidate satellite. Through this method, the second measurement report only indicates whether a cell belongs to the cell corresponding to the candidate satellite, enabling the access network device to directly determine the cell corresponding to the candidate satellite without excessively increasing the data content of the first indication information. This ensures service transmission efficiency while improving the decision-making effectiveness of the access network device in subsequently assisting the terminal device in selecting the cell corresponding to the candidate satellite for access.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the first indication information is sent by a core network element; the first indication information includes any one of the following: a paging message and / or a proprietary signaling message related to the terminal device.

[0022] In conjunction with the first aspect, in certain implementations of the first aspect, the core network elements include at least one of the following: Mobility Management Entity (MME) network element; Serving Gateway (SGW) network element; Home Subscriber Server (HSS) network element; Packet Data Network Gateway (PGW) network element; and Access and Mobility Management Function (AMF) network element. By utilizing the above methods and sending the first indication information using different types of core network elements, the message transmission needs in different communication scenarios can be met, and service transmission efficiency can be improved.

[0023] In conjunction with the first aspect, in certain implementations of the first aspect, the core network elements include a first network element and a second network element. The core network equipment includes terrestrial core network equipment and satellite-based core network equipment. The first network element is a network element within the terrestrial core network equipment, and the second network element is a network element within the satellite-based core network equipment. The first indication information is sent by the first network element and the second network element. The first network element provides the first indication information to the second network element, and the second network element, upon receiving the first indication information, sends it to the access network equipment. By utilizing core network elements deployed in different locations to provide the first indication information to the access network equipment, the message transmission needs under different communication scenarios can be met, ensuring that the access network equipment can successfully obtain the first indication information and improving service transmission efficiency.

[0024] In conjunction with the first aspect, in some implementations of the first aspect, the core network elements include a second network element, and the core network equipment includes satellite-based core network equipment. The second network element is a network element within the satellite-based core network equipment; the first indication information is sent by the second network element. Through the above method, by utilizing the core network elements deployed in the ground-based core network equipment to provide the first indication information to the access network equipment, the message transmission needs under different communication scenarios can be met, ensuring that the access network equipment can successfully obtain the first indication information and improving service transmission efficiency.

[0025] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: sending second indication information to the terminal device, the second indication information indicating at least one cell, the cell belonging to the cell corresponding to the candidate satellite. Through this method, at least one cell is determined using multiple candidate satellites to assist the terminal device in accessing the cell corresponding to the candidate satellite, increasing the probability of the terminal device accessing the cell corresponding to the candidate satellite, thereby shortening the communication latency of the terminal device.

[0026] In conjunction with the first aspect, in some implementations of the first aspect, the second indication information indicates the target cell, which is the cell with the highest priority among multiple cells; or, the second indication information indicates the priorities of multiple cells corresponding to candidate satellites, and the priorities of multiple cells are used to determine the target cell. By using the above method, the priorities corresponding to multiple cells are determined using multiple candidate satellites, improving the accuracy of cell indication and the completeness of the indication content, increasing the probability of the terminal device accessing the cell corresponding to the candidate satellite, and thus improving the service transmission efficiency of the terminal device.

[0027] In conjunction with the first aspect, in certain implementations of the first aspect, a second measurement report sent by the receiving terminal device is included. The second measurement report includes measurement results for a second cell and third indication information, whereby the third indication information indicates whether the second cell belongs to the cell corresponding to the candidate satellite. By indicating the cell corresponding to the candidate satellite in the measurement report using the above method, the probability of the terminal device accessing the cell corresponding to the candidate satellite is increased, thereby improving the service transmission efficiency of the terminal device.

[0028] Secondly, a communication method is provided for use in a terminal device. The method includes: sending first indication information to an access network device, wherein the first indication information indicates multiple candidate satellites corresponding to the terminal device, the candidate satellites are satellites configured by the core network device for the terminal device, and the candidate satellites are used to provide cells for the terminal device to access.

[0029] It should be understood that the technical effects of the second aspect of the technical solution can be referred to the relevant description in the first aspect, and will not be repeated here.

[0030] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information indicates multiple satellite identifiers, and the multiple satellite identifiers correspond to multiple candidate satellites respectively.

[0031] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information indicates multiple indices, which are used to indicate satellite identifiers, and the multiple indices correspond to multiple satellite identifiers respectively.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information indicates multiple first fields; wherein, the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether there is information of the (i+1)-th candidate satellite in the first indication information, and the information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, where i is a positive integer.

[0033] In conjunction with the second aspect, in some implementations of the second aspect, when the i-th first field takes the first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite; when the i-th first field takes the second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information indicates at least one of the following: a second field, which indicates the number of candidate satellites in the first indication information; and a third field, which indicates the length of the data packet corresponding to the first indication information, the length of which is used to determine the number of candidate satellites.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the above method further includes: receiving a first message sent by the access network device, the first message being used to request the terminal device to send first indication information.

[0036] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information is carried in any of the following ways: MAC CE; or, RRC message; or, first measurement report.

[0037] In conjunction with the second aspect, in some implementations of the second aspect, the first indication information is a first measurement report, which includes the measurement results of a first cell, and the first cell belongs to the cell corresponding to the candidate satellite; the first measurement report includes second indication information, which is used to indicate the candidate satellite corresponding to the first cell.

[0038] In conjunction with the second aspect, in some implementations of the second aspect, the second indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell.

[0039] In conjunction with the second aspect, in some implementations of the second aspect, the above method further includes: sending a second measurement report to the access network equipment, the second measurement report including the measurement results of the second cell and third indication information, the third indication information being used to indicate whether the second cell belongs to the cell corresponding to the candidate satellite.

[0040] In conjunction with the second aspect, in some implementations of the second aspect, the above method further includes: receiving second indication information sent by the access network device, the second indication information indicating at least one cell, the cell belonging to the cell corresponding to the candidate satellite.

[0041] In conjunction with the second aspect, in some implementations of the second aspect, the second indication information indicates the target cell, which is the cell with the highest priority among multiple cells; or, the second indication information indicates the priority of multiple cells corresponding to the candidate satellite, and the priority of multiple cells is used to determine the target cell.

[0042] In conjunction with the second aspect, in some implementations of the second aspect, the above method further includes: obtaining a third measurement report, which includes measurement results corresponding to multiple candidate cells; determining a target cell based on the second indication information and the third measurement report; and accessing the target cell.

[0043] Thirdly, a communication method is provided, applied to a core network device. The method includes: sending first indication information to an access network device, the first indication information indicating multiple candidate satellites corresponding to a terminal device, the candidate satellites being satellites configured by the core network device for the terminal device, and the candidate satellites being used to provide access to the cell for the terminal device.

[0044] It should be understood that the technical effects of the third aspect's technical solution can be referred to the relevant description in the first aspect, and will not be repeated here.

[0045] In conjunction with the third aspect, in some implementations of the second aspect, the first indication information indicates multiple satellite identifiers, and the multiple satellite identifiers correspond to multiple candidate satellites respectively.

[0046] In conjunction with the third aspect, in some implementations of the second aspect, the above method further includes: receiving a second message sent by the access network device, the second message being used to request the core network device to send first indication information.

[0047] In conjunction with the third aspect, in some implementations of the second aspect, the first indication information is carried in any of the following: a paging message and / or a dedicated signaling message related to the terminal device.

[0048] In conjunction with the second aspect, in some implementations of the second aspect, the core network equipment includes core network elements, and the first indication information is sent by the core network element. The core network element includes at least one of the following: Mobility Management Entity (MME) element; Serving Gateway (SGW) element; Home Subscriber Server (HSS) element; Packet Data Network Gateway (PGW) element; Access and Mobility Management Function (AMF) element.

[0049] In conjunction with the third aspect, in some implementations of the second aspect, the core network element includes a first network element and a second network element, and the core network equipment includes terrestrial core network equipment and satellite-based core network equipment. The first network element is a network element in the terrestrial core network equipment, and the second network element is a network element in the satellite-based core network equipment. The first network element sends a first indication message to the second network element. When the second network element receives the first indication message, it sends the first indication message to the access network equipment through the second network element.

[0050] In conjunction with the third aspect, in some implementations of the second aspect, the core network element includes a second network element, the core network equipment includes satellite-based core network equipment, and the second network element is a network element in the satellite-based core network equipment; the first instruction information is sent to the access network equipment through the second network element.

[0051] Fourthly, a communication device is provided, comprising a communication module and a processing module. This communication device is used to execute the method in any possible implementation of any of the above aspects.

[0052] Fifthly, a communication device is provided, including a processor. The processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the methods in any possible implementation of any of the above aspects. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0053] In one implementation, the communication interface may be a transceiver, or an input / output interface.

[0054] In another implementation, the communication device is a chip configured within a communication device. When the communication device is a chip configured within a communication device, the communication interface can be an input / output interface.

[0055] In a sixth aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute a method in any possible implementation of any aspect.

[0056] In specific implementation, the processor can be one or more chips, the input circuit can be input pins, the output circuit can be output pins, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to and transmitted by a transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as both the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0057] In a seventh aspect, a communication device is provided, including a processor and a memory. The processor is used to read instructions stored in the memory and to receive signals via a receiver and transmit signals via a transmitter to execute the method in any possible implementation of any of the above aspects.

[0058] Optionally, the processor may be one or more, and the memory may be one or more.

[0059] Eighthly, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions), which, when run, causes a computer to perform a method in any possible implementation of any of the above aspects.

[0060] In a ninth aspect, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when executed on a computer, causes the computer to perform the methods in any possible implementation of any of the preceding aspects.

[0061] In a tenth aspect, embodiments of this application provide a chip system including one or more processors for calling and executing instructions stored in memory, causing the methods in any of the above aspects or possible implementations to be executed. The chip system may be composed of chips or may include chips and other discrete devices.

[0062] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0063] Eleventhly, a communication system is provided, including the aforementioned core network equipment, access network equipment, and terminal equipment. Optionally, the communication system may also include other communication equipment. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of a communication system according to an embodiment of this application.

[0065] Figure 2 This is a schematic diagram of a communication process in a store-and-forward scenario according to an embodiment of this application.

[0066] Figure 3 This is a schematic diagram of a communication process in a store-and-forward scenario according to an embodiment of this application.

[0067] Figure 4 This is a flowchart of a communication method according to an embodiment of this application.

[0068] Figure 5 This is a schematic diagram of a satellite identifier according to an embodiment of this application.

[0069] Figure 6 This is an index diagram of an embodiment of this application.

[0070] Figure 7 This is a schematic diagram of a first field according to an embodiment of this application.

[0071] Figure 8 This is a schematic diagram of a second field according to an embodiment of this application.

[0072] Figure 9 This is a schematic diagram of a third field according to an embodiment of this application.

[0073] Figure 10 This is a schematic diagram of a third field according to an embodiment of this application.

[0074] Figure 11 This is a flowchart of a communication method according to an embodiment of this application.

[0075] Figure 12 This is a schematic diagram of a communication device according to an embodiment of this application.

[0076] Figure 13 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0077] To facilitate understanding of the embodiments of this application, the terminology used in this application will be briefly explained first. Optionally, the explanation of some terms may also refer to the explanations in the 3rd Generation Partnership Project (3GPP) standard protocol.

[0078] First, the relevant terms in the embodiments of this application will be introduced.

[0079] A cell is the smallest management unit in a mobile communication network. It can also be understood as a wireless signal coverage unit composed of a base station and its coverage area. A base station can also be called an access network device. The coverage area of ​​each access network device can be divided into at least one cell, and each cell can correspond to at least one frequency point.

[0080] In the embodiments of this application, different cells may correspond to the same access network device or different access network devices. For example, the first cell and the second cell are two different cells. The first cell and the second cell may belong to the same access network device, that is, the access network device can manage the first cell and the second cell at the same time. Alternatively, the first cell belongs to the first access network device and the second cell belongs to the second access network device, that is, the first cell and the second cell are managed by different access network devices.

[0081] Cell handover: Cell handover refers to the process in a wireless communication system where, when a terminal device moves from one cell to another or gets closer to another cell, it needs to switch from the connection state with the current cell to accessing another cell in order to maintain the communication continuity of the terminal device.

[0082] In this embodiment, the source cell refers to the cell that provides services to the terminal device before the handover, and the target cell refers to the cell that provides services to the terminal device after the handover. The configuration information of the target cell (such as the physical cell identifier, frequency information, and random access resource information required for handover to the target cell) can be indicated by a handover message, for example, through an RRC reconfiguration message. This handover message is sent from the access network device corresponding to the source cell (i.e., the source access network device) to the terminal device, or the handover message is sent from the access network device of the target cell (i.e., the target access network device) to the source access network device, and then forwarded by the source access network device to the terminal device.

[0083] Optionally, cell handover includes either intra-site handover or inter-site handover. Intra-site handover refers to the source cell and target cell belonging to the same access network device, where the source cell and target cell can be the same cell or different cells. Inter-site handover refers to the source cell and target cell belonging to different access network devices. This application does not limit the scope of handover in this regard.

[0084] It should be understood that the source cell corresponds to the source access network equipment or the source base station, and the target cell corresponds to the target access network equipment or the target base station.

[0085] In the embodiments of this application, the target cell may also refer to the final cell determined by the terminal device when performing cell reselection; or, the target cell may also refer to the cell to be handed over determined by the terminal when making a handover decision (e.g., when performing conditional handover).

[0086] Cell selection: Cell selection refers to the process by which a terminal device searches for all frequency points allowed by the mobile network and selects a suitable cell to camp on when it is powered on or enters the coverage area of ​​the access network device from a blind spot.

[0087] Cell reselection: Cell reselection refers to the process by which a terminal device detects the signal strength or communication quality of neighboring cells and the current cell to select a cell with better communication quality for access.

[0088] Random access: Random access refers to the process from the access network device sending a random access preamble index to the terminal device to the establishment of a connection between the terminal device and the access network device. The random access procedure can be applied to scenarios such as cell handover and cell reselection.

[0089] Optionally, random access can be divided into contention-based random access and non-contention-based random access.

[0090] Contention-based random access (CBRA)

[0091] The resources used in CFRA are CFRA resources, which are dedicated random access channel (RACH) resources. The CBRA process may specifically include the following steps S1 to S4.

[0092] Step S1: The terminal device sends a preamble to the access network device.

[0093] The terminal device randomly selects a preamble from the shared preamble pool as message 1 (msg1) and sends the preamble index to the corresponding beam of the access network device through the physical random access channel (PRACH).

[0094] Step S2: The access network device sends a random access response (RAR) to the terminal device.

[0095] After receiving the preamble index, the access network device requests a cell-radio network temporary identifier (C-RNTI) and uplink / downlink scheduling resources. Then, the access network device sends a Random Access Response (RAR) as message 2 (msg2) via the physical downlink shared channel (PDSCH). A single PDSCH can carry RARs for multiple terminal devices.

[0096] Step S3: The terminal device sends an RRC connection request to the access network device.

[0097] The terminal device will send message 3 (msg3) to the access network device on the specified uplink resources, which contains the terminal device's corresponding identifier and the necessary information required to establish an RRC connection.

[0098] Step S4: The access network device sends an RRC connection setup message to the terminal device.

[0099] When the access network device receives a message / data sent by the terminal device on the allocated UL grant resource, if there is no conflict (or no contention), the access network device sends a contention resolution message as message 4 (msg4) to the terminal device. For example, the access network device sends an RRC establishment message to the terminal device. After this, the terminal device can communicate with the access network device.

[0100] Contention-free random access (CFRA)

[0101] The resources used by CFRA can include preamble indexes and time-frequency resources. In New Radio (NR) networks, CFRA resources can be CFRA resources associated with a specific beam within the cell. If the access network device has configured CFRA resources for the terminal device, the terminal device can use those resources to initiate the CFRA procedure. If CFRA fails or the access network device has not configured CFRA resources, the terminal device can initiate CBRA to the access network device. CBRA resources can be understood as public resources, and terminal devices can use CBRA resources to execute the CBRA procedure through contention.

[0102] The CFRA process may specifically include the following steps S10 to S20.

[0103] Step S10: The terminal device sends a preamble to the access network device.

[0104] The terminal device sends the random access preamble index (or random access preamble sequence) to the access network device as message 1 via PRACH. In a non-contention-based random access procedure, this random access preamble index is pre-assigned to the terminal device by the access network device. That is, this random access preamble index is dedicated to the terminal device.

[0105] Step S20: The access network device sends a random access response (RAR) to the terminal device.

[0106] The access network device sends message 2 (msg2) to the terminal device, which includes a random access response.

[0107] Paging: Paging is a mechanism used in network communication to notify terminal devices of incoming calls, data or other network events, usually when the device is in an idle or inactive state.

[0108] Non-access stratum (NAS): A protocol used for communication between terminal devices and mobility management entity (MME) network elements.

[0109] The solutions of the embodiments of this application are described below with reference to the accompanying drawings. The cell handover method provided in this application can be applied to various wireless communication systems.

[0110] The technical solutions provided in this application can be applied to various communication systems, such as: Global System for Mobile Communications (GSM) systems, General Packet Radio Service (GPRS), Wireless Local Area Network (WLAN), Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, sidelink communication systems, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication systems, non-terrestrial network (NTN) communication systems, 5th generation (5G) mobile communication systems, or new radio access technology (NR). Among these, 5G mobile communication systems can include non-standalone (NSA) and / or standalone (SA) networking. The technical solutions provided in this application can also be applied to future communication systems. This application does not limit the scope of these applications.

[0111] Figure 1 This is a schematic diagram of a communication system 100 used in an embodiment of this application. The communication system 100 may include network devices, such as... Figure 1 The network device 110 is shown. The communication system 100 may also include terminal devices, such as... Figure 1 The terminal device 120 shown. The network device 110 and the terminal device 120 can communicate via a wireless link.

[0112] Figure 1 An exemplary network device 110 and a terminal device 120 are shown. Optionally, the communication system 100 may also include multiple network devices and / or multiple terminal devices.

[0113] The network equipment in this application can be network-side equipment such as access network and core network equipment. Access network equipment is sometimes also called access node. Access network equipment has wireless transceiver capabilities and is used to communicate with terminals. Access network equipment includes, but is not limited to, base stations, evolved NodeBs (eNodeBs), transmission reception points (TRPs) in the above-mentioned communication systems, next-generation NodeBs (gNBs) in 5G mobile communication systems, access network equipment or modules of access network equipment in open RAN (ORAN) systems, satellites in NTN communication systems, base stations in future mobile communication systems, or access nodes in WiFi systems. Access network equipment can also be modules or units capable of implementing some of the functions of a base station. Access network equipment can be macro base stations, micro base stations, or indoor stations, relay nodes or donor nodes, or wireless controllers in cloud radioaccess network (CRAN) scenarios. Optionally, access network equipment can also be servers, wearable devices, or vehicle-mounted equipment, etc. For example, the access network equipment in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). Multiple access network devices in a communication system can be base stations of the same type or different types. Base stations can communicate with terminals directly or via relay stations. Terminals can communicate with multiple base stations using different access technologies. The embodiments of this application do not limit the specific technology or device form used in the access network equipment. In this application, the access network equipment is referred to as a network device.

[0114] In this application, the means for implementing the functions of a network device can be a network device itself, or a means capable of supporting the network device in implementing those functions, such as a processor, circuit, chip, or chip system. This means can be installed in or connected to the network device. In the technical solutions provided in this application, the example of a network device being used to implement the functions of a network device is used to describe the technical solutions provided in this application.

[0115] The terminal device in this application can be a wireless terminal device capable of receiving network device scheduling and instruction information. The wireless terminal device can be a device providing voice and / or data connectivity to a user, a handheld device with wireless connectivity, or other processing devices connected to a wireless modem. For example, the terminal device can communicate with one or more core networks or the Internet via a radio access network (RAN). The terminal device can also be referred to as a terminal, user equipment (UE), mobile station, mobile terminal, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), ultra-reliable low-latency communication (URLLC), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, or satellite communication, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle, drone, helicopter, airplane, hot air balloon, ship, robot, robotic arm, or smart home device, etc. The embodiments of this application do not limit the form of the terminal device.

[0116] In this application, the apparatus for implementing the functions of a terminal device can be the terminal device itself, or any apparatus capable of supporting the terminal device in implementing those functions, such as a processor, circuit, chip, or chip system. This apparatus can be installed in or connected to the terminal device. In the technical solutions provided in this application, the example of a terminal device being used to implement the functions of a terminal device is used to describe the technical solutions provided in this application.

[0117] Access network devices and / or terminals can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. This application does not limit the application scenarios of the access network devices and terminals. Access network devices and terminal devices can be deployed in the same or different scenarios; for example, both can be deployed on land; or the access network device can be deployed on land, and the terminal device on water, etc., and so on.

[0118] The following section provides a detailed introduction to the background of non-terrestrial networks (NTN).

[0119] As an illustration, the NTN system consists of the following network elements.

[0120] • One or more gateways: used to connect satellite and terrestrial public networks.

[0121] • Feeder link: A link used for communication between the gateway and the satellite.

[0122] • Service link: A link used for communication between terminal equipment and satellites.

[0123] Satellites can be divided into two types based on the functions they provide: transparent payloads and regenerative payloads.

[0124] • Transparent payload: Provides only wireless frequency filtering, frequency conversion, and amplification functions. It only provides transparent signal forwarding and does not change the waveform signal it forwards.

[0125] • Regenerative payload: In addition to providing wireless frequency filtering, frequency conversion, and amplification functions, it can also provide demodulation / decoding, routing / conversion, and encoding / modulation functions. It has some or all of the functions of a base station.

[0126] • Inter-satellite links (ISL): These exist in regenerative payload scenarios and are used for communication between satellites.

[0127] Currently, 3GPP considers two types of satellites: transparent payload satellites and regenerative payload satellites. These two types of satellites will be introduced below.

[0128] Please refer to Figure 2 It illustrates a different NTN system where the communication satellites are regenerated satellites. For example... Figure 2 As shown, the NTN system includes: terminal equipment 101, satellite 201, NTN gateway 301, and core network equipment 501.

[0129] exist Figure 2In the system shown, the functions of the access network equipment are integrated into satellite 201; that is, satellite 201 possesses the functions of an access network device. Terminal device 101 and satellite 201 can communicate via an air interface (e.g., Uu interface). Satellite 201 and NTN gateway 301 (usually located on the ground, but can also be mounted on a satellite) can communicate via a satellite radio interface (SRI).

[0130] exist Figure 2 In the system shown, taking uplink transmission as an example, terminal device 101 sends uplink signals to satellite 201, satellite 201 forwards the uplink signals to NTN gateway 301, and then NTN gateway 301 sends the uplink signals to core network device 501.

[0131] Indicative, except Figure 2 Besides the NTN system based on regenerable satellites shown, there is another NTN system based on store-and-forward satellites. In this system, in addition to the functions of the access network equipment being integrated on the satellite, some functions of the core network equipment are also integrated on the satellite. For example, some core network elements are deployed on the satellite to realize the relevant functions corresponding to the original core network equipment.

[0132] In a store-and-forward NTN scenario, for example, in one scenario, both the serving link and the feeder link can be active simultaneously. In another scenario, such as store-and-forward, the serving link and the feeder link cannot be active simultaneously. That is, when the feeder link is active, the serving link is unavailable. In this case, the terminal device cannot communicate with the satellite, but the core network device can communicate with the satellite through the gateway. Similarly, when the feeder link is unavailable, the serving link is available. It is worth noting that in the store-and-forward scenario, satellites communicate with each other via inter-satellite links, unaffected by the status of the serving link and the feeder link. In other words, regardless of whether the serving link and the feeder link are active, satellites can communicate with each other via inter-satellite links. Please refer to [reference needed]. Figure 3 It illustrates a communication process in a store-and-forward scenario according to this application, such as... Figure 3 As shown, in the NTN scenario based on store-and-forward satellites, the gateway and the satellite communicate through feeder links, including uplink feeder links and downlink feeder links. The satellite and the terminal equipment communicate through service links, including uplink service links and downlink service links.

[0133] It is worth noting that, in the embodiments of this application, the process of the core network device communicating with the satellite through the gateway can also be understood as the core network device communicating with the satellite, and the embodiments of this application do not limit this.

[0134] In the above Figure 2 and Figure 3 In the network architecture shown, access network devices are used to provide wireless communication services to terminal devices. Access network devices and terminal devices can establish connections to communicate, including signaling and data exchange. There can be multiple access network devices, and two adjacent access network devices can communicate via wired or wireless means. Terminal devices can switch between different access network devices, that is, establish connections with different access network devices.

[0135] In the above Figures 2 to 3 For access network equipment, core network equipment, and terminal equipment, please refer to... Figure 1 The relevant descriptions will not be repeated here.

[0136] Furthermore, taking the 5G NTN system as an example, an NTN system can include multiple satellites. A single satellite can cover a certain area of ​​the ground, providing wireless communication services to terminal devices in that area. Additionally, satellites can orbit the Earth, and by deploying multiple satellites, communication coverage can be achieved for different areas of the Earth's surface.

[0137] NTN technology can be combined with various communication systems. For example, NTN technology can be combined with NR systems to form an NR-NTN system; or, for example, NTN technology can be combined with Internet of Things (IoT) systems to form an IoT-NTN system. The technical solutions described in the embodiments of this application are applicable to the above-mentioned systems, and this application does not limit them.

[0138] The 4G network architecture released by the 3GPP standards group is illustrative and includes: terminals, access networks supporting 3GPP technologies, Mobility Management Entity (MME) network elements, Serving Gateway (SGW) network elements, Packet Data Network Gateway (PGW) network elements, Home Subscriber Server (HSS) network elements, Data Network (DN) network elements, Policy and Charging Rules Function (PCRF) network elements, and Service Capability Exposure Function (SCEF) network elements.

[0139] MME, SGW, PGW, HSS, DN, PCRF, and SCEF are network elements of the 3GPP core network (referred to as core network elements). These network elements constitute the core network equipment.

[0140] The MME (Mobile Module) element is used for mobility management and control, including terminal device authentication, paging, location updates, and handover. For example, during satellite communication, the terminal device needs to periodically report its location to the MME element. If it needs to communicate with access network equipment on the satellite, the MME element can transmit signaling to the access network equipment. In addition, if the terminal device needs to hand over to another cell, the MME element also needs to coordinate the handover process.

[0141] The 5G network architecture released by the 3GPP standards group is illustrative and includes: terminals, access networks supporting 3GPP technologies (including radio access network, RAN or access network, AN), user plane function (UPF) network elements, access and mobility management function (AMF) network elements, session management function (SMF) network elements, policy control function (PCF) network elements, application function (AF) network elements, DN network elements, network slice selection function (NSSF) network elements, authentication server function (AUSF) network elements, and unified data management (UDM) network elements.

[0142] The AMF network element can be used to manage terminal access to the core network, such as terminal location updates, network registration, access control, terminal mobility management, and terminal attachment and detachment. While providing services for a terminal's session, the AMF network element can also provide control plane storage resources for that session to store the session identifier and the associated SMF network element identifier.

[0143] As described above in the technical background, in current satellite communication technology scenarios, during or after a terminal device performs a Non-Access Stratum (NAS) procedure, the core network equipment configures multiple candidate satellites for the terminal device. The terminal device can utilize these candidate satellites to assist in determining the target cell that can currently provide service. If the target cell corresponds to a candidate satellite, the terminal device can directly execute the cell access procedure or the NAS procedure. However, if the target cell does not correspond to a candidate satellite, the terminal device needs to re-register with the satellite corresponding to the target cell before accessing the target cell or executing the NAS procedure. This requires the satellite to verify the terminal device's relevant equipment information. This process reduces the efficiency of the terminal device when accessing the target cell, thereby reducing the service transmission efficiency of the terminal device. Therefore, this application provides a communication method that aims to obtain the configuration information of the candidate satellites corresponding to the terminal device through the access network equipment, further assisting the terminal device in determining the target cell that can provide service, increasing the probability that the target cell belongs to a candidate satellite, and thus improving the service transmission efficiency of the terminal device.

[0144] In view of the above, the communication method provided in the embodiments of this application will be described in detail. For illustrative purposes, please refer to the following: Figure 4 It illustrates a schematic flowchart of a communication method provided in an exemplary embodiment of this application, such as... Figure 4 As shown, the method includes the following steps.

[0145] S410, the terminal device sends a first indication information to the access network device. The first indication information indicates multiple candidate satellites corresponding to the terminal device. The candidate satellites are satellites configured by the core network device for the terminal device. The candidate satellites are used to provide cells for the terminal device to access. Correspondingly, the access network device receives the first indication information.

[0146] The access network equipment refers to the access network equipment in NTN.

[0147] For illustrative purposes, the access network equipment, core network equipment, and terminal equipment in this embodiment are all related devices in NTN.

[0148] Indicatively, when the access network device and the terminal device are in a communication state, the terminal device sends a first instruction message to the access network device.

[0149] Indicatively, the geographical area covered by a candidate satellite is called the cell corresponding to the candidate satellite.

[0150] As an illustration, core network equipment consists of multiple core network elements.

[0151] Optionally, in one example, during a random access process between a terminal device and an access network device, the terminal device sends a first indication message to the access network device. This first indication message can be related signaling during the random access process. For example, during a CBRA process, the terminal device sends message 1 containing a preamble to the access network device, using message 1 as the first indication message, or carrying the first indication message within message 1. Another example is during a CBRA process, after the terminal device obtains uplink synchronization, it uses the uplink resources allocated by the access network device to transmit message 3, using message 3 as the first indication message, or carrying the first indication message within message 3. Yet another example is that the first indication message is a special signaling transmitted during the random access process; that is, the first indication message is not related signaling involved in the random access process, but rather a message sent separately by the terminal device to the access network device during the random access process.

[0152] Alternatively, in another example, after the terminal device completes access with the access network device, the terminal device sends a first indication message to the access network device.

[0153] Alternatively, in another example, in the NTN system, because satellites move periodically along a designated orbit, when a satellite reaches a designated position along its orbit, and the terminal device is not within the coverage area corresponding to that position, the terminal device can no longer communicate with the satellite. That is, for the terminal device, the satellite has a corresponding service duration; when the communication duration between the satellite and the terminal device reaches the service duration, the satellite can no longer communicate with the terminal device. Therefore, after the terminal device completes access with the satellite, and before the service duration corresponding to the satellite ends, the terminal device sends a first indication message to the access network device.

[0154] In an illustrative NTN scenario, core network equipment connects to the satellite network via a gateway to provide satellite communication services to terminal devices. Therefore, the core network equipment configures a satellite list for the terminal devices, enabling them to select appropriate satellites for communication. The candidate satellites are those in the satellite list.

[0155] Indicatively, candidate satellites are associated with relevant information, including at least one of the following: satellite identifier, orbital parameters (e.g., longitude or inclination), communication frequency, or polarization. The communication frequency refers to the probability that a mobile terminal will achieve a pre-set call quality within a designated service area, and the polarization refers to the change in the direction of the electric field vector over time during electromagnetic wave propagation.

[0156] In illustrative terms, during registration, attachment, and tracking area updates between core network equipment and terminal equipment, the core network equipment can provide the terminal equipment with configuration information for multiple candidate satellites. During registration and attachment, when the terminal equipment initiates a registration or attachment request to the core network equipment, the core network equipment can include the configuration information for multiple candidate satellites in the response message sent back to the terminal equipment. During tracking area updates, when the terminal equipment moves from one tracking area to another and initiates a tracking area update request to the core network equipment, the core network equipment, in its response message corresponding to the tracking area update request, sends the updated configuration information for the multiple candidate satellites to the terminal equipment, or resends the configuration information for the multiple candidate satellites to the terminal equipment. Furthermore, the core network equipment can also send the configuration information for multiple candidate satellites to the terminal equipment via dedicated signaling.

[0157] In this embodiment, under the store-and-forward scenario, when the feeder link is active, the ground core network equipment sends the configuration information of the candidate satellites to the satellites (e.g., the core network equipment or access network equipment on the satellites) via the feeder link. The satellites, when the service link is active, then send the configuration information of the candidate satellites to the terminal equipment via the service link. The terminal equipment stores the configuration information of the candidate satellites upon receiving it. In this case, the network-side equipment on the satellites (including access network equipment or core network elements) does not store the configuration information of the candidate satellites upon receiving it. Therefore, in this embodiment, the terminal equipment provides the candidate satellites by sending a first indication message to the access network equipment.

[0158] In this embodiment, under the store-and-forward scenario, the core network device on the satellite sends the configuration information of the candidate satellites to the access network device on the satellite. The satellite, with the service link active, then sends the configuration information of the candidate satellites to the terminal device via the service link. The terminal device stores the configuration information of the candidate satellites upon receiving it. In this case, the access network device on the satellite does not store the configuration information of the candidate satellites upon receiving it; therefore, in this embodiment, the terminal device provides the candidate satellites by sending a first indication message to the access network device.

[0159] Optionally, the configuration information of the aforementioned candidate satellites may include at least one of the following: satellite identifier, orbital parameters, communication frequency, polarization mode, etc.

[0160] Optionally, all satellites in the satellite list generated by the core network device are candidate satellites provided by the core network device to the terminal device; or, some satellites in the satellite list are candidate satellites provided by the core network device to the terminal device, while others are not candidate satellites corresponding to the terminal device. Therefore, in this embodiment, candidate satellites are used to represent satellites configured by the core network device to the terminal device.

[0161] Indicatively, after obtaining the configuration information corresponding to the candidate satellites, the terminal device stores the relevant information and subsequently sends the first indication information of multiple candidate satellites to the access network device. The first indication information may contain only all or part of the relevant information of the candidate satellites.

[0162] Optionally, the access network device is an access network device mounted on a first satellite, which is one of the candidate satellites configured by the core network device for the terminal device; or, the first satellite is not a candidate satellite configured by the core network device for the terminal device, and this application embodiment does not limit this.

[0163] In some embodiments, the candidate satellite is a satellite that provides downlink data transmission and / or downlink signaling transmission for the terminal device; it may also be a satellite that monitors store-and-forward services for the terminal device.

[0164] To illustrate, downlink data transmission refers to the process of a candidate satellite sending data to a terminal device, while downlink signaling transmission refers to the process of a candidate satellite sending signaling to a terminal device.

[0165] In a store-and-forward scenario, candidate satellites store the received data or signaling and then forward it to the terminal equipment.

[0166] In some embodiments, the first indication information indicates multiple satellite identifiers, each corresponding to a multiple candidate satellite.

[0167] Optionally, the satellite identifier corresponding to the candidate satellite reported by the terminal device to the access network device can be the satellite identifier provided by the core network device to the terminal device; or it can be the satellite identifier obtained by mapping the reported satellite identifier through a specified mapping rule.

[0168] In illustrative terms, the satellite identifier is used to uniquely identify the candidate satellite. The satellite identifier is provided by the core network equipment to the terminal equipment; alternatively, the terminal equipment receives the configuration information of the candidate satellite, the first indication information indicates the initial satellite identifier corresponding to the candidate satellite, and the initial satellite identifier is mapped to the corresponding satellite identifier through a specified mapping rule.

[0169] For illustrative purposes only, different candidate satellites correspond to different satellite identifiers. For example, candidate satellite 1 corresponds to satellite identifier 1 (e.g., 00000001), candidate satellite 2 corresponds to satellite identifier 2 (e.g., 00000010), and candidate satellite 3 corresponds to satellite identifier 3 (e.g., 00000011). Please refer to the following: Figure 5 It illustrates a schematic diagram of a satellite identifier provided in an exemplary embodiment of this application, such as... Figure 5As shown, the first indication information carries n satellite identifiers, where each satellite identifier corresponds to a candidate satellite, and each satellite identifier occupies eight bits in the first indication information. This illustration only shows that the satellite identifier of the candidate satellite is represented by eight bits, but it can also occupy other numbers of bits, and this application embodiment does not limit this.

[0170] In some embodiments, the first indication information indicates multiple indices, which are used to indicate satellite identifiers, and the multiple indices correspond to multiple satellite identifiers respectively.

[0171] Indicatively, based on the use of satellite identifiers to indicate candidate satellites, the first indication information carries multiple indices, with different indices used to indicate different satellite identifiers.

[0172] Indicatively, in the first indication information, the satellite identifier and index corresponding to the same candidate satellite are arranged in association. For example, for the indication information 1 and satellite identifier 1 corresponding to candidate satellite 1, in the first indication information, the indication information 1 is located before the satellite identifier 1. After the access network device receives the first indication information, during the data reading process, when the indication information 1 is read, the satellite identifier 1 is determined according to the indication information 1.

[0173] Optionally, each satellite identifier in the first indication information has a corresponding index; or, at least one satellite identifier in the first indication information has a corresponding index.

[0174] This is illustrative; please refer to it. Figure 10 This illustrates an index diagram provided in an exemplary embodiment of this application, such as... Figure 6 As shown, the first indication information includes satellite identifiers corresponding to m candidate satellites, each satellite identifier having a corresponding index. Index 1 indicates satellite identifier 1, and the second indication information 2 indicates satellite identifier 2. Figure 6 Each row represents eight bits. Therefore, Index 1 and Satellite Identifier 1 occupy eight bits in the first indication information, with Index 1 occupying 3 bits and Satellite Identifier 1 occupying 5 bits. Along with each satellite identifier, corresponding index information is also provided. This illustration only shows that the candidate satellite's satellite identifier uses five bits and the index uses three bits; other numbers of bits can also be used, and this application embodiment is not limited to this.

[0175] Optionally, in the first indication information, the index and satellite identifier corresponding to the same candidate satellite are transmitted in the same frame. For example, index 1 and satellite identifier 1 are different fields in the same frame. Alternatively, the index and satellite identifier corresponding to the same candidate satellite are transmitted in different frames. For example, index 2 and satellite identifier 2 are transmitted in different frames. This application embodiment does not limit this.

[0176] In some embodiments, the first indication information includes a plurality of first fields; wherein the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether there is information of the (i+1)-th candidate satellite in the first indication information, and the information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, where i is a positive integer.

[0177] In illustrative terms, when the first indication information indicates multiple candidate satellites, the multiple candidate satellites are associated with multiple first fields respectively. For example, candidate satellite 1 is associated with first field a. In this case, first field a is used to determine whether candidate satellite 2 still exists in the first indication information. Similarly, if candidate satellite 2 exists, candidate satellite 2 is associated with first field b. First field b is used to determine whether candidate satellite 3 still exists in the first indication information.

[0178] Optionally, the first field may be associated with the satellite identifier corresponding to the candidate satellite, or the first field may be associated with the index of the candidate satellite. This application embodiment does not limit this.

[0179] Optionally, the presence of a next candidate satellite in the first indication information can be determined by different values ​​of the first field. For example, when the first field is 1, it indicates that there is a satellite identifier or index corresponding to the next candidate satellite in the first indication information; when the first field is 0, it indicates that there is no satellite identifier or index corresponding to the next candidate satellite in the first indication information. Alternatively, the presence of a next candidate satellite in the first indication information can be determined by different field lengths of the first field. For example, when the length of the first field is one bit, it indicates that there is a satellite identifier or index corresponding to the next candidate satellite in the first indication information; when the length of the first field is two bits, it indicates that there is no satellite identifier or index corresponding to the next candidate satellite in the first indication information. This application embodiment does not limit this.

[0180] In some embodiments, when the i-th first field takes a first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite; when the i-th first field takes a second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite.

[0181] Optionally, the first value is 0 and the second value is 1, or the first value is 1 and the second value is 0, or the first value and the second value are other values, which are not limited in this embodiment.

[0182] In this embodiment, please refer to Figure 7 It illustrates a schematic diagram of the first field provided in an exemplary embodiment of this application, such as... Figure 7As shown, the first indication information includes satellite identifiers corresponding to k candidate satellites. Each satellite identifier corresponds to a first field. For example, first field 1 corresponds to satellite identifier 1, and second field 2 corresponds to satellite identifier 2. Taking first field 1 as an example, if the value of first field 1 is 1, it means that satellite identifier 2 corresponding to candidate satellite 2 exists in the first indication information. If the value of first field 1 is 0, it means that satellite identifier 2 corresponding to candidate satellite 2 does not exist in the first indication information. Figure 7 As shown by satellite identifier 2 corresponding to candidate satellite 2 in the first indication information, by Figure 7 As can be seen, each row represents eight bits. Since the first field 1 can take values ​​of both 0 and 1, it occupies one bit in the first indication information, and the satellite identifier 1 occupies seven bits. This schematic diagram is only used to illustrate that the satellite identifier of the candidate satellite is used with eight bits, but it can also occupy other numbers of bits. This application embodiment does not limit this.

[0183] In some embodiments, the first indication information includes at least one of the following: a second field, which indicates the number of candidate satellites in the first indication information; and a third field, which indicates the length of the data packet corresponding to the first indication information, wherein the data packet length is used to determine the number of candidate satellites.

[0184] Schematic illustration: The second field indicates the number of candidate satellite configuration information included in the first indication information. In one example, the second field is represented as "10" (in binary form), indicating that the first indication information includes configuration information for two candidate satellites (e.g., at least one of satellite identifiers and indices). The number of candidate satellites can be obtained by converting the binary form of the second field to decimal form. In another example, taking the inclusion of satellite identifiers corresponding to candidate satellites in the first indication information as an example, each satellite identifier occupies a certain number of bits in the first indication information. The second field is implemented as length information, indicating a fixed number of bits. The number of candidate satellites included in the first indication information is calculated based on the second field and the number of bits corresponding to a single satellite identifier. Please refer to [reference needed]. Figure 8 This illustrates a schematic diagram of the second field provided in an exemplary embodiment of this application, such as... Figure 8 As shown, the first indication information includes satellite identifiers corresponding to r candidate satellites. The first indication information also includes a second field, which is used to determine the number of satellite identifiers included in the first indication information. The number of satellite identifiers can be used to determine the satellite identifiers of the candidate satellites in the first indication information. Figure 8Each row in the first indication information represents eight bits. Therefore, the second field occupies eight bits in the first indication information, and each satellite identifier occupies eight bits in the first indication information. This illustration only shows that the satellite identifier of the candidate satellite is represented by eight bits, but it can also occupy other numbers of bits. This application embodiment does not limit this.

[0185] Indicatively, the first indication information is transmitted in the form of data packets. The third field is used to indicate the length of the data packet corresponding to the first indication information. In one example, taking the satellite identifiers corresponding to candidate satellites as an example, each satellite identifier occupies a certain number of bits in the first indication information. The number of candidate satellites included in the first indication information is calculated based on the third field and the number of bits corresponding to a single satellite identifier.

[0186] Optionally, the first indication information is subheading information, or the first indication information is control information.

[0187] In some embodiments, the first indication information includes a second field, and the satellite identifier corresponds to a first number of bits in the first indication information; the number of candidate satellites in the first indication information is determined based on the first number of bits and the second field corresponding to the multiple satellite identifiers respectively.

[0188] To illustrate, taking the number of bits occupied by a single satellite identifier in the first indication information as the first bit count, and the second field occupying a certain number of bits in the first indication information, if each satellite identifier occupies the same number of bits, the number of bits occupied by the second field is divided by the first bit count, and the result of this division is taken as the number of satellite identifiers, thus determining the number of candidate satellites in the first indication information. If different satellite identifiers occupy different numbers of bits, the number of candidate satellites in the first indication information is determined based on the number of bits corresponding to the first satellite identifier and the number of bits corresponding to the second field.

[0189] In illustratively, in another example, the number of candidate satellites in the first indication information is determined based on the number of bits occupied by the index corresponding to a single candidate satellite in the first indication information and the number of bits corresponding to the second field.

[0190] In some embodiments, the first indication information includes a third field, and the satellite identifier corresponds to a second number of bits in the first indication information; the number of candidate satellites in the first indication information is determined based on the second number of bits and the third field corresponding to multiple satellite identifiers respectively.

[0191] Schematic example, taking the information volume of a single satellite identifier in the first indication information as measured in bytes or bits, the third field indicates the data packet length (expressed in bytes or bits). If each satellite identifier occupies the same number of bytes or bits, the data packet length indicated by the third field is divided by the second number of bits or bytes. The result of this division is used as the number of satellite identifiers, thus determining the number of candidate satellites in the first indication information. If different satellite identifiers occupy different numbers of bits, the number of candidate satellites in the first indication information is determined based on the second number of bits corresponding to each satellite identifier and the number of bits corresponding to the data packet length. Please refer to [reference needed]. Figure 9 This illustrates a schematic diagram of a third field provided in an exemplary embodiment of this application, such as... Figure 9 As shown, the first indication information includes a third field, which indicates the length of the data packet corresponding to the first indication information. Figure 9 Each row in the first indication information represents eight bits; therefore, the third field occupies eight bits in the first indication information. This illustration only shows the third field using eight bits, but it can also occupy other numbers of bits; this application does not limit this.

[0192] In some embodiments, the data packet length is used to indicate the length of the corresponding MAC service data unit (MAC SDU) or the length of the corresponding MAC CE, and the data packet length is in bytes or bits. In some embodiments, the length of the data occupied by the satellite identifier corresponding to the candidate satellite is in bits or bytes, which is not limited in this application embodiment.

[0193] In view of the above, the first indication information is only used to indicate candidate satellites. The following is an explanation of the situation where the first indication information also carries other data.

[0194] In some embodiments, the first indication information includes a fourth field, and the first indication information further includes at least one fourth field. The fourth field includes other information besides the satellite identifier in the first indication information. The fourth field corresponds to the third bit number in the first indication information, and the satellite identifier corresponds to the fourth bit number in the first indication information. The first length is obtained by subtracting the third bit number from the data packet length corresponding to the fourth field. The number of candidate satellites in the first indication information is determined based on the fourth bit number corresponding to the multiple satellite identifiers and the first length.

[0195] In illustrative terms, the fourth field represents other information in the first indication information. Taking the number of bits occupied by the fourth field in the first indication information as the third bit count, and the number of bits occupied by a single satellite identifier in the first indication information as the fourth bit count, the data packet length corresponding to the fourth field is expressed in bits. Subtracting the third bit count from the data packet length yields the remaining bits corresponding to the first indication information, which is used as the first length. If each satellite identifier occupies the same number of bits, the first length is divided by the fourth bit count. The result of this division is used as the number of satellite identifiers, thereby determining the number of candidate satellites in the first indication information. Please refer to [reference needed]. Figure 10 This illustrates a schematic diagram of the fourth field provided in an exemplary embodiment of this application, such as... Figure 10 As shown, the first indication information includes other information 1 and other information 2, as well as s satellite identifiers, where other information 1 and other information 2 correspond to the fourth field, in Figure 10 Each row in the first indication information represents eight bits. Therefore, other information occupies eight bits in the first indication information, and each satellite identifier also occupies eight bits in the first indication information. This illustration only shows that other information and satellite identifiers use eight bits, but other numbers of bits can also be used, and this application embodiment does not limit this. In addition, the first indication information also includes a third field (not shown).

[0196] In some embodiments, the first indication information is carried in any of the following: a Media Access Control Unit (MAC CE); a Radio Resource Control (RRC) message; or a first measurement report.

[0197] Optionally, the first indication information is transmitted in the form of MAC CE signaling, and the message content corresponding to MAC CE can refer to the content described in the above embodiments; or, the first indication information is transmitted in the form of RRC message, and the message content corresponding to RRC message can refer to the content described in the above embodiments; or, the first indication information is a first measurement report, wherein the first measurement report may include, in addition to the measurement results corresponding to multiple cells respectively, the content described in the above embodiments, and this application is an embodiment and does not limit it in this way.

[0198] In some embodiments, the first indication information is carried in a first measurement report, which includes the measurement results of a first cell, which belongs to the cell corresponding to the candidate satellite; the first indication information is used to indicate the candidate satellite corresponding to the first cell.

[0199] In some embodiments, the first indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell.

[0200] As an illustration, during the connection process between the terminal device and the access network device, the terminal device measures the signal quality and network performance of multiple cells, generates a measurement report based on the measurement results, and uploads it to the access network device. Optionally, the measurement results include at least one of the following: reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), or signal-to-interference-noise ratio (RS-SINR) for the corresponding cell.

[0201] Indicatively, the first measurement report includes the measurement results corresponding to the first cell corresponding to the candidate satellite, and the first cell has first indication information, which indicates the candidate satellite corresponding to the first cell; or, the first indication information is indicated as the satellite identifier or index corresponding to the candidate satellite corresponding to the first cell. This application embodiment does not limit this.

[0202] In some embodiments, the terminal device sends a second measurement report to the access network device, wherein the second measurement report includes the measurement results of the second cell and third indication information, the third indication information being used to indicate whether the second cell is the cell corresponding to the candidate satellite.

[0203] As an illustration, the terminal device measures the signal quality of multiple cells and generates a measurement report, which is then uploaded to the access network equipment. Optionally, the measurement results may include at least one of the following: reference signal power, received signal strength indication, reference signal reception quality, or signal-to-interference-plus-noise ratio (SINR) for the corresponding cell.

[0204] Indicatively, the measurement report includes the measurement results corresponding to the second cell. The second cell has a third indication information, which is used to indicate whether the second cell is the cell corresponding to the candidate satellite. In one example, the third indication information corresponds to 1 bit. If the value of this bit is 0, it means that the second cell is not the cell corresponding to the candidate satellite. If the value of this bit is 1, it means that the second cell is the cell corresponding to the candidate satellite.

[0205] In another example, the second measurement report includes measurement results from the second cell, as well as information related to candidate satellites.

[0206] Optionally, the relevant information includes at least one of the following: satellite identifier corresponding to the candidate satellite, index (used to indicate the satellite identifier corresponding to the candidate satellite), first field (used to indicate whether there is a satellite identifier of the next candidate satellite in the second measurement report), second field (indicating the number of candidate satellites), and third field (indicating the data packet length corresponding to the second measurement report). This application embodiment does not limit this.

[0207] In some embodiments, the access network device sends a first message to the terminal device, wherein the first message is used to request the terminal device to send first indication information.

[0208] Indicatively, before the terminal device sends the first indication information to the access network device, the access network device sends a first message to the terminal device to request the terminal device to report the first indication information. After the terminal device receives the first message, it then sends the first indication information to the access network device.

[0209] S420, the access network device sends a second indication information to the terminal device, the second indication information indicating at least one cell, the at least one cell belonging to the cell corresponding to the candidate satellite; correspondingly, the terminal device receives the second indication information.

[0210] It should be understood that step S420 is optional. That is, the access network device may or may not execute step S420. For example, in step S410, the access network device receives the first indication information and can use the content of the first indication information as a reference for subsequent decisions. Whether to send the second indication information to the terminal device depends on the implementation of the access network device and is not limited here.

[0211] The second indication information indicates at least one cell, which belongs to the cell corresponding to the candidate satellite.

[0212] Indicatively, the area covered by a candidate satellite can be called a cell. After dividing the area covered by the candidate satellite, multiple subdivisions are obtained, and each subdivision corresponds to a cell.

[0213] In some embodiments, the second indication information indicates the target cell, which is the cell with the highest priority among multiple cells; or, the second indication information indicates the priority of multiple cells corresponding to the candidate satellite, and the priority of multiple cells is used to determine the target cell.

[0214] For illustrative purposes, cell priority refers to the priority order during cell selection, reselection, or handover processes in a network. The third cell is the cell corresponding to one or more candidate satellites among multiple candidate satellites, and its priority is the first priority.

[0215] In some examples, after receiving the first indication information, the access network device determines multiple candidate satellites corresponding to the terminal device based on the first indication information, and determines multiple cells corresponding to the candidate satellites. The cell with the highest priority is determined as the third cell (i.e., the target cell), and further, the priority corresponding to the third cell is determined.

[0216] Optionally, the priority determination method can be based on measurements of multiple cells, including signal quality, signal strength, cell load, network capacity, etc. The measurement results of multiple cells are obtained, and the cell with the highest priority is determined as the third cell, with the priority corresponding to the third cell set as the first priority. The access network device sends a second indication message to the terminal device, carrying the first priority corresponding to the third cell in the second indication message. Here, signal quality includes signal stability and transmission rate, cell load refers to the number of terminal devices accessing the cell simultaneously, and network capacity refers to the network capacity and frequency band allocation.

[0217] In another example, in addition to receiving the first indication information, the access network device also receives a measurement report message uploaded by the terminal device. The access network device combines the measurement results of multiple cells in the measurement report message to determine the first priority corresponding to the third cell from the first indication information. The cell measured in the measurement report message can be a cell corresponding to a candidate satellite or a cell corresponding to a non-candidate satellite. For the access network device, the cell corresponding to a candidate satellite has a higher priority than the cell corresponding to a non-candidate satellite.

[0218] In some embodiments, the terminal device obtains a third measurement report, which includes measurement results corresponding to multiple candidate cells; based on the second indication information and the third measurement report, it determines the target cell; and the terminal device accesses the target cell.

[0219] In illustrative terms, after the terminal device sends the first instruction information to the access network device, during the process of the terminal device determining the target cell, a third measurement report is obtained. The third measurement report may be the same as or different from the measurement results of the candidate cells contained in the first measurement report and the second measurement report. This application embodiment does not limit this.

[0220] In this embodiment, after receiving the second indication information, the terminal device combines the first priority corresponding to the third cell in the second indication information and the measurement results corresponding to the candidate cells in the third measurement report to determine the target cell and access the target cell. The target cell can be the third cell, or it can be a cell that does not correspond to a candidate satellite; this embodiment does not limit the specific choice.

[0221] In some embodiments, multiple candidate satellites correspond to multiple fourth cells; a second priority corresponding to each of the multiple fourth cells is determined based on a first indication information; a second indication information is sent to a terminal device, the second indication information indicating the second priority corresponding to each of the multiple fourth cells.

[0222] In some examples, multiple candidate satellites correspond to multiple fourth cells. After receiving the first indication information, the access network device determines the multiple candidate satellites corresponding to the terminal device based on the first indication information, and determines the multiple fourth cells corresponding to the candidate satellites. Furthermore, it determines the priority of each of the multiple fourth cells. The multiple fourth cells are used to determine the target cell for the terminal device to access.

[0223] Optionally, the priority determination method is based on measurements of multiple fourth cells, including signal quality, signal strength, cell load, network capacity, etc., to obtain measurement results for multiple fourth cells. The priorities corresponding to each of the multiple fourth cells are determined based on the measurement results, and the priority corresponding to the fourth cell is used as the second priority. The access network device sends second indication information to the terminal device, carrying the first priority corresponding to the multiple fourth cells in the second indication information.

[0224] In another example, in addition to receiving the first indication information, the access network device also receives a measurement report message uploaded by the terminal device. The access network device combines the measurement results of multiple cells in the measurement report message to determine the second priority corresponding to multiple fourth cells from the first indication information. The cells measured in the measurement report message can be cells corresponding to candidate satellites or cells corresponding to non-candidate satellites. For the access network device, the priority of cells corresponding to candidate satellites is higher than that of cells corresponding to non-candidate satellites.

[0225] In some embodiments, a fifth cell is determined based on the first indication information, the fifth cell being the cell corresponding to the candidate satellite; and a second indication information is sent to the terminal device, the second indication information indicating the fifth cell.

[0226] In some examples, after receiving the first indication information, the access network device determines multiple candidate satellites corresponding to the terminal device based on the first indication information, and determines multiple cells corresponding to the candidate satellites, and further determines the cell with the highest priority as the fifth cell.

[0227] Optionally, priority can be determined based on measurements of multiple cells, including signal quality, signal strength, cell load, network capacity, etc. The measurement results of multiple cells are obtained, and the cell with the highest priority is determined as the fifth cell. A second indication message is sent to the terminal device, indicating the configuration information of the fifth cell (e.g., the cell identifier of the fifth cell).

[0228] In another example, in addition to receiving the first indication information, the access network device also receives a measurement report message uploaded by the terminal device. The access network device combines the measurement results of multiple cells in the measurement report message and determines the cell with the highest priority and belonging to the candidate satellite from the first indication information as the fifth cell. The cell measured in the measurement report message can be the cell corresponding to the candidate satellite or the cell corresponding to a non-candidate satellite. For the access network device, the cell corresponding to the candidate satellite has a higher priority than the cell corresponding to the non-candidate satellite.

[0229] As an illustration, the first instruction message can be sent by the core network equipment in addition to the terminal equipment. Please refer to the example provided. Figure 11 It illustrates a schematic flowchart of a communication method provided in an exemplary embodiment of this application, such as... Figure 11 As shown, the method includes the following steps.

[0230] S1110, the core network device sends a first indication information to the access network device. The first indication information includes multiple candidate satellites corresponding to the terminal device. The candidate satellites are satellites configured by the core network device for the terminal device. The candidate satellites are used to provide cells for the terminal device to access. Correspondingly, the access network device receives the first indication information.

[0231] The access network equipment refers to the access network equipment in NTN.

[0232] For illustrative purposes, the access network equipment, core network equipment, and terminal equipment in this embodiment are all related devices in NTN.

[0233] Indicatively, when the access network device and the core network device are in communication, the core network device sends a first instruction message to the access network device.

[0234] In an illustrative NTN scenario, core network equipment connects to the satellite network via a gateway to provide satellite communication services to terminal devices. Therefore, the core network equipment configures a satellite list for the terminal devices, enabling them to select appropriate satellites for communication. The candidate satellites are those in the satellite list.

[0235] Indicatively, candidate satellites have corresponding configuration information, including at least one of the following: satellite identifier, orbital parameters (e.g., longitude or inclination), communication frequency, or polarization mode. The communication frequency refers to the probability that a mobile terminal will achieve a pre-set call quality during a call within a specified service area, and the polarization mode refers to the change in the direction of the electric field vector over time during the propagation of electromagnetic waves.

[0236] Indicatively, during registration, attachment, and tracking area updates between core network equipment and terminal equipment, the core network equipment can provide the terminal equipment with configuration information for multiple candidate satellites. During registration and attachment, after establishing a connection between the core network equipment and the terminal equipment via satellites, when the terminal equipment initiates a registration or attachment request, the core network equipment can include the configuration information of multiple candidate satellites in the response message sent back to the terminal equipment. During tracking area updates, when the terminal equipment moves from one tracking area to another, it initiates a tracking area update request to the core network equipment. When sending back the response message corresponding to the tracking area update request, the core network equipment sends the updated configuration information for multiple candidate satellites to the terminal equipment, or resends the configuration information for multiple candidate satellites to the terminal equipment. Furthermore, the core network equipment can also send the configuration information of multiple candidate satellites to the terminal equipment via dedicated signaling.

[0237] In some examples, in store-and-forward scenarios, when the feeder link is active, the core network device sends the configuration information of candidate satellites to the satellites via the feeder link. The satellites, when the serving link is active, then send the configuration information of the candidate satellites to the terminal devices via the serving link. The terminal devices store the configuration information of the candidate satellites upon receipt. In this case, the network-side devices on the satellites (including access network devices or core network elements) also store the configuration information of the candidate satellites upon receipt. Therefore, within a given phase, the access network devices can determine multiple candidate satellites corresponding to the terminal devices through the core network devices. If the network-side devices on the satellites (including access network devices or core network elements) do not store the configuration information of the candidate satellites upon receipt, the core network devices send the first indication information to the access network devices again.

[0238] In some embodiments, the first indication information is carried in any of the following: a paging message and / or a proprietary signaling message associated with the terminal device.

[0239] Indicatively, the core network equipment carries the first indication information in the paging message sent to the access network equipment.

[0240] Indicatively, the core network equipment may send a dedicated information message related to the terminal equipment to the access network equipment, which carries first indication information, such as a User Equipment Information Transmission (UE INFORMATION TRANSFER) message.

[0241] In some embodiments, the core network element includes a first network element and a second network element. The core network equipment includes terrestrial core network equipment and satellite-based core network equipment. The first network element is a network element in the terrestrial core network equipment, and the second network element is a network element in the satellite-based core network equipment. The first indication information is sent by the first network element and the second network element. The first network element is used to provide the first indication information to the second network element, and the second network element is used to send the first indication information to the access network equipment after receiving the first indication information.

[0242] In an illustrative manner, during the process of sending the first indication information from a core network element in a core network device to an access network device, in a store-and-forward scenario, the core network element includes a first network element and a second network element. The first network element refers to the network element in the terrestrial core network device, and the second network element is the network element in the satellite core network device. Taking the paging phase as an example, the first network element sends a paging message to the second network element. After receiving the paging message (carrying the first indication information), the second network element forwards either the paging message or the first indication information to the access network device. The first network element sends a dedicated signaling message related to the terminal device to the second network element. After receiving the dedicated signaling message related to the terminal device (carrying the first indication information), the second network element forwards either the dedicated signaling message related to the terminal device or the first indication information to the access network device.

[0243] In some embodiments, the core network element includes a second network element, and the core network equipment includes a satellite-on-a-core-network device. The second network element is a network element in the satellite-on-a-core-network device; the first indication information is sent by the second network element.

[0244] In a schematic manner, during the process of sending the first indication information from the core network element in the core network equipment to the access network equipment, in the store-and-forward scenario, the core network element includes a second network element, which is a network element in the core network equipment on the satellite; the second network element generates the first indication information from the configuration information corresponding to the stored candidate satellite and sends it to the access network equipment.

[0245] In another example, during the process of sending the first indication information to the access network device through the core network element in the core network device, in the store-and-forward scenario, the core network element includes the first network element, which is a network element in the ground core network device; the first network element generates the first indication information by storing the configuration information corresponding to the candidate satellite and sends it to the access network device.

[0246] In some embodiments, the core network elements include at least one of the following: Mobility Management Entity (MME) network element; Serving Gateway (SGW) network element; Home Subscriber Server (HSS) network element; Packet Data Network Gateway (PGW) network element; Access and Mobility Management Function (AMF) network element.

[0247] As an illustration, the network element that sends the first indication information varies depending on the NTN technology used. For example, in the IoT-NTN scenario, the MME network element is used to send the first indication information to the access network device. In the NR-NTN scenario, the AMF network element is used to send the first indication information to the access network device. This application does not limit this aspect.

[0248] Optionally, the following S1120 is an optional step. That is, the access network device may or may not execute S1120. This application embodiment does not limit this.

[0249] S1120, the access network device sends a second indication message to the terminal device, and the terminal device receives the second indication message.

[0250] The relevant content in S1120 can be found in the content about S420 in the above embodiments, and will not be repeated here.

[0251] In some embodiments, the access network device is an access network device mounted on a first satellite. After receiving the first indication information, the access network device can also send the first indication information to an access network device mounted on a second satellite, so that the access network device on the second satellite assists the terminal device in determining the target cell.

[0252] It should be understood that the above embodiments of this application use the interaction between core network equipment, access network equipment, and terminal equipment as examples for illustration, but are not limited thereto. For example, the communication method provided in this application can also be applied to core network equipment, access network equipment, satellites, and terminal equipment. For instance, a terminal equipment sends a first indication message to satellite B, and satellite B forwards the first indication message to the access network equipment; or, a core network equipment sends a first indication message to satellite B, and satellite B sends the first indication message to the access network equipment. If the access network equipment is located on a satellite, such as satellite A, it can also be described as satellite B receiving the first indication message and then sending the first indication message to satellite A.

[0253] The transmission of the second instruction information can also follow other similar paths. For example, the access network device (or satellite A) sends it to satellite B, and satellite B then sends the second instruction information to the terminal device.

[0254] In other words, this application does not limit the various information transfer paths, and the communication system to which the communication method of this application can be applied is not limited to the communication device in the example of this application.

[0255] The communication method of the embodiments of this application has been described above with reference to the accompanying drawings. It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially, these steps are not necessarily executed in the order shown in the figures. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the steps or stages of other steps. The communication device of the embodiments of this application will now be described with reference to the accompanying drawings.

[0256] Figure 12 This is a schematic block diagram of a communication device provided in an embodiment of this application. Figure 12 As shown, the communication device 1200 may include a communication module 1220. The communication module 1220 can implement corresponding communication functions, which can be internal communication functions of the communication device 700 or communication functions between the communication device 1200 and other devices. Optionally, the communication module 1220 may also be called a communication interface or transceiver module. Optionally, the communication device 1200 further includes a processing module 1210. The processing module 1210 can implement corresponding processing functions. Optionally, the communication device 1200 can be any one of a terminal device, a core network device, or an access network device; the following description uses an access network device as an example.

[0257] Optionally, the communication device 1200 further includes a storage module, which can be used to store instructions and / or data; the processing module 1210 can read the instructions and / or data in the storage module so that the communication device 1200 can implement the aforementioned method embodiments.

[0258] In one possible design, the communication device 1200 may correspond to the terminal device in the above method embodiments, or a component (such as a circuit, chip, or chip system) configured in the terminal device. The communication device 1200 can be used to perform the steps or processes performed by the terminal device in any of the above method embodiments.

[0259] For example, the communication module 1220 is used to receive first indication information, which indicates multiple candidate satellites corresponding to the terminal device. The candidate satellites are satellites configured by the core network equipment for the terminal device, and the candidate satellites are used to provide the cell for the terminal device to access. The first indication information comes from the terminal device; or, the first indication information comes from a core network element in the core network equipment.

[0260] In some examples, the first indication information indicates multiple satellite identifiers, each of which corresponds to a multiple candidate satellite.

[0261] In some examples, the first indication information indicates multiple indices that indicate satellite identifiers of the candidate satellites, and the multiple indices correspond to the multiple satellite identifiers respectively.

[0262] In some examples, the first indication information includes multiple first fields;

[0263] Wherein, the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether there is information of the (i+1)-th candidate satellite in the first indication information. The information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, and i is a positive integer.

[0264] In some examples, when the i-th first field takes the first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite;

[0265] When the i-th first field takes the second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite.

[0266] In some examples, the first indication information includes at least one of the following:

[0267] The second field indicates the number of candidate satellites;

[0268] The third field is used to indicate the length of the data packet corresponding to the first indication information, and the data packet length is used to determine the number of candidate satellites.

[0269] In some examples, the communication module 1220 is further configured to send a first message to the terminal device, the first message being used to request the terminal device to send the first indication information; or, to send a second message to the core network element, the second message being used to request the core network element to send the first indication information.

[0270] In some examples, the first indication information comes from the terminal device; the first indication information is carried in any of the following: a Media Access Control Unit (MAC CE); a Radio Resource Control (RRC) message; or a first measurement report.

[0271] In some examples, the first indication information is carried in the first measurement report, which includes the measurement results of a first cell, which belongs to the cell corresponding to the candidate satellite; the first indication information is used to indicate the candidate satellite corresponding to the first cell.

[0272] In some instances, the first indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell.

[0273] In some examples, the first indication information comes from a core network element in the core network device; the first indication information is carried in any of the following: a paging message; or a proprietary signaling message related to the terminal device.

[0274] In some examples, the core network element includes a first network element and a second network element, and the core network equipment includes terrestrial core network equipment and satellite-based core network equipment. The first network element is a network element in the terrestrial core network equipment, and the second network element is a network element in the satellite-based core network equipment. The first indication information is sent by the first network element and the second network element, wherein the first network element is used to provide the first indication information to the second network element, and the second network element is used to send the first indication information to the access network equipment after receiving the first indication information.

[0275] In some examples, the core network element includes a second network element, and the core network equipment includes a satellite-on-a-core-network device, wherein the second network element is a network element in the satellite-on-a-core-network device; the first indication information is sent by the second network element.

[0276] In some examples, the communication device 1200 further includes a processing module 1210, which is used to determine a first priority corresponding to a third cell based on the first indication information, wherein the third cell is the cell corresponding to the candidate satellite; and to send second indication information to the terminal device, wherein the second indication information indicates the first priority corresponding to the third cell.

[0277] In some examples, the multiple candidate satellites correspond to multiple fourth cells;

[0278] Processing module 1210 is configured to determine the second priority corresponding to each of the plurality of fourth cells based on the first indication information; and send second indication information to the terminal device, wherein the second indication information indicates the second priority corresponding to each of the plurality of fourth cells.

[0279] In some examples, the processing module 1210 is configured to determine a fifth cell based on the first indication information, the fifth cell being the cell corresponding to the candidate satellite; and send second indication information to the terminal device, the second indication information indicating the fifth cell.

[0280] In some examples, the communication module 1220 is also configured to receive a second measurement report sent by the terminal device, the second measurement report including the measurement results of the second cell and third indication information, the third indication information being used to indicate whether the second cell is the cell corresponding to the candidate satellite.

[0281] The above are merely examples; for detailed steps or procedures, please refer to the descriptions in the foregoing embodiments.

[0282] Figure 13 This is another schematic block diagram of the communication device 1300 provided in the embodiments of this application. The communication device 1300 may be a chip, chip system, or processor, etc., in a terminal device or network device that implements the above-described methods. The communication device 1300 can be used to implement the methods described in the above-described method embodiments; for details, please refer to the descriptions in the above-described method embodiments.

[0283] like Figure 13 As shown, the communication device 1300 may include one or more processors 1310, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 1310 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the communication device 1300 (e.g., a base station, baseband chip, user, user chip), execute software programs, and process data from the software programs.

[0284] In an alternative design, the processor 1310 may also store instructions and / or data that can be executed by the processor 1310 to cause the communication device 1300 to perform the methods described in the above method embodiments.

[0285] In another alternative design, the communication device 1300 may include a communication interface 1320 for implementing receiving and transmitting functions. For example, the communication interface 1320 may be a transceiver circuit, interface, interface circuit, or transceiver. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and transmitting functions may be separate or integrated. The aforementioned transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0286] Optionally, the communication device 1300 may include one or more memories 1330, which may store instructions that can be executed on the processor 1310, causing the communication device 1300 to perform the methods described in the above method embodiments. Optionally, the memories 1330 may also store data. Optionally, the processor 1310 may also store instructions and / or data. The processor 1310 and the memories 1330 may be provided separately or integrated together.

[0287] It should be understood that, in one possible design, the steps in the method embodiments provided in this application can be implemented by integrated logic circuits in the processor's hardware or by instructions in software form. The steps of the methods disclosed in the embodiments of this application can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0288] In one implementation, the communication device 1300 may correspond to the terminal device in the above method embodiments and may be used to execute the various steps and / or processes executed by the terminal device in the above method embodiments. The processor 1310 may be used to execute instructions stored in the memory 1330, and when the processor 1310 executes the instructions stored in the memory, the processor 1310 is used to execute the various steps and / or processes of the above method embodiments corresponding to the terminal device.

[0289] In another implementation, the communication device 1300 can correspond to a network device in the above method embodiments, such as an access network device or a core network device, and can be used to execute the various steps and / or processes executed by the access network device or the core network device in the above method embodiments. The processor 1310 can be used to execute instructions stored in the memory 1330, and when the processor 1310 executes the instructions stored in the memory, the processor 1310 is used to execute the various steps and / or processes of the above method embodiments corresponding to the network device.

[0290] It should be understood that the aforementioned processing device can be one or more chips. For example, the processing device can be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system-on-chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0291] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0292] According to the method provided in the embodiments of this application, this application also provides a chip system, which includes one or more processors for calling and executing instructions stored in memory, thereby causing the method described in the embodiments of this application to be executed. The chip system may be composed of chips or may include chips and other discrete devices.

[0293] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0294] According to the method provided in the embodiments of this application, this application also provides a communication system, which includes the aforementioned network device and terminal device.

[0295] According to the method provided in the embodiments of this application, this application also provides a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the network device or terminal device in any of the foregoing method embodiments.

[0296] According to the method provided in the embodiments of this application, this application also provides a computer-readable storage medium storing program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the network device or terminal device in any of the foregoing method embodiments.

[0297] The computer-readable storage medium may be the aforementioned volatile memory or non-volatile memory, or it may include both volatile memory and non-volatile memory.

[0298] In the embodiments of this application, the terms and English abbreviations are exemplary examples given for ease of description and should not be construed as limiting the application in any way. This application does not preclude the possibility of defining other terms that can achieve the same or similar functions in existing or future agreements.

[0299] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated.

[0300] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0301] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0302] In summary, the above description is merely a preferred embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, The method is applied to an access network device, wherein the access network device is an access network device in a non-terrestrial network (NTN), and the method includes: Receive first indication information, the first indication information indicating multiple candidate satellites corresponding to the terminal device, the candidate satellites being satellites configured by the core network equipment for the terminal device, the candidate satellites being used to provide the cell for the terminal device to access; Wherein, the first indication information comes from the terminal device; or, the first indication information comes from a core network element in the core network device.

2. The method according to claim 1, characterized in that, The first indication information indicates multiple satellite identifiers, and the multiple satellite identifiers correspond to the multiple candidate satellites respectively.

3. The method according to claim 1 or 2, characterized in that, The first indication information indicates multiple indices, which are used to indicate the satellite identifiers of the candidate satellites, and the multiple indices correspond to multiple satellite identifiers respectively.

4. The method according to any one of claims 1 to 3, characterized in that, The first indication information includes multiple first fields; Wherein, the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether there is information of the (i+1)-th candidate satellite in the first indication information. The information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, and i is a positive integer.

5. The method according to claim 4, further characterized in that, When the i-th first field takes the first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite; When the i-th first field takes the second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite.

6. The method according to any one of claims 1 to 5, characterized in that, The first indication information includes at least one of the following: The second field indicates the number of candidate satellites; The third field is used to indicate the length of the data packet corresponding to the first indication information, and the data packet length is used to determine the number of candidate satellites.

7. The method according to any one of claims 1 to 6, characterized in that, Before receiving the first indication information, the method further includes: Send a first message to the terminal device, the first message being used to request the terminal device to send the first indication information; or... A second message is sent to the core network element, the second message being used to request the core network element to send the first indication information.

8. The method according to any one of claims 1 to 7, characterized in that, The first indication information comes from the terminal device; The first indication information carries at least one of the following: Media Access Control Unit (MAC CE); or, Radio Resource Control (RRC) message; or, First measurement report.

9. The method according to claim 8, characterized in that, The first indication information is carried in the first measurement report, which includes the measurement results of the first cell, and the first cell belongs to the cell corresponding to the candidate satellite; The first indication information is used to indicate the candidate satellites corresponding to the first cell.

10. The method according to claim 9, characterized in that, The first indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell.

11. The method according to any one of claims 1 to 10, characterized in that, The first indication information comes from the core network element; The first indication information is carried in a paging message and / or a proprietary signaling message related to the terminal device.

12. The method according to any one of claims 1 to 11, characterized in that, The method further includes: Send a second indication message to the terminal device, the second indication message indicating at least one cell, the cell belonging to the cell corresponding to the candidate satellite.

13. The method according to claim 12, characterized in that, The second indication information indicates a target cell, which is the highest priority cell among multiple cells; or, The second indication information indicates the priority of multiple cells corresponding to the candidate satellite, and the priority of the multiple cells is used to determine the target cell.

14. The method according to any one of claims 1 to 13, characterized in that, The method further includes: The terminal device receives a second measurement report, which includes the measurement results of the second cell and third indication information. The third indication information is used to indicate whether the second cell belongs to the cell corresponding to the candidate satellite.

15. A communication method, characterized in that, The method is applied to a terminal device, wherein the terminal device is a terminal device in a non-terrestrial network (NTN), and the method includes: A first indication message is sent to the access network device. The first indication message indicates multiple candidate satellites corresponding to the terminal device. The candidate satellites are satellites configured by the core network device for the terminal device. The candidate satellites are used to provide the cell for the terminal device to access.

16. The method according to claim 15, characterized in that, The first indication information indicates multiple satellite identifiers, and the multiple satellite identifiers correspond to the multiple candidate satellites respectively.

17. The method according to claim 15 or 16, characterized in that, The first indication information indicates multiple indices, which are used to indicate the satellite identifiers of the candidate satellites, and the multiple indices correspond to multiple satellite identifiers respectively.

18. The method according to any one of claims 15 to 17, characterized in that, The first indication information indicates multiple first fields; Wherein, the i-th first field corresponds to the information of the i-th candidate satellite, and the i-th first field is used to indicate whether there is information of the (i+1)-th candidate satellite in the first indication information. The information of the candidate satellite includes the satellite identifier or index corresponding to the candidate satellite, and i is a positive integer.

19. The method according to claim 18, further characterized in that, When the i-th first field takes the first value, the i-th first field is used to indicate that the first indication information includes information about the (i+1)-th candidate satellite; When the i-th first field takes the second value, the i-th first field is used to indicate that the first indication information does not include information about the (i+1)-th candidate satellite.

20. The method according to any one of claims 15 to 19, characterized in that, The first indication information indicates at least one of the following: The second field indicates the number of candidate satellites; The third field is used to indicate the length of the data packet corresponding to the first indication information, and the data packet length is used to determine the number of candidate satellites.

21. The method according to any one of claims 15 to 20, characterized in that, Before sending the first indication information to the access network device, the method further includes: The terminal device receives a first message sent by the access network device, the first message being used to request the terminal device to send the first indication information.

22. The method according to any one of claims 15 to 21, characterized in that, The first indication information is carried in any of the following ways: MAC CE; or, RRC message; or, First measurement report.

23. The method according to claim 22, characterized in that, The first indication information is carried in the first measurement report, which includes the measurement results of the first cell, and the first cell belongs to the cell corresponding to the candidate satellite; The first indication information indicates the candidate satellite corresponding to the first cell.

24. The method according to claim 23, characterized in that, The first indication information indicates the satellite identifier of the candidate satellite corresponding to the first cell.

25. The method according to any one of claims 15 to 24, characterized in that, The method further includes: A second measurement report is sent to the access network device. The second measurement report includes the measurement results of the second cell and third indication information. The third indication information is used to indicate whether the second cell belongs to the cell corresponding to the candidate satellite.

26. The method according to any one of claims 15 to 25, characterized in that, The method further includes: The system receives a second indication message sent by the access network device, the second indication message indicating at least one cell, the cell belonging to the cell corresponding to the candidate satellite.

27. The method according to claim 26, characterized in that, The second indication information indicates a target cell, which is the highest priority cell among multiple cells; or, The second indication information indicates the priority of multiple cells corresponding to the candidate satellite, and the priority of the multiple cells is used to determine the target cell.

28. The method according to claim 27, characterized in that, The method further includes: Obtain a third measurement report, which includes measurement results corresponding to multiple candidate cells; Based on the second indication information and the third measurement report, the target cell is determined; Access the target cell.

29. A communication method, characterized in that, The method is applied to core network equipment, wherein the core network equipment is a core network equipment in a non-terrestrial network (NTN), and the method includes: A first indication message is sent to the access network device. The first indication message indicates multiple candidate satellites corresponding to the terminal device. The candidate satellites are satellites configured by the core network device for the terminal device. The candidate satellites are used to provide the cell for the terminal device to access.

30. The method according to claim 29, characterized in that, The first indication information indicates multiple satellite identifiers, and the multiple satellite identifiers correspond to the multiple candidate satellites respectively.

31. The method according to claim 29 or 30, characterized in that, Before sending the first indication information to the access network device, the method further includes: The system receives a second message sent by the access network device, the second message being used to request the core network device to send the first indication information.

32. The method according to any one of claims 29 to 31, characterized in that, The first indication information is carried in any one of the following: Paging messages and / or dedicated signaling messages related to the terminal device.

33. A communication device, characterized in that, The device is an access network device, comprising: A communication module is configured to receive first indication information, which indicates multiple candidate satellites corresponding to a terminal device. The candidate satellites are satellites configured by the core network equipment for the terminal device, and the candidate satellites are used to provide the cell for the terminal device to access. The first indication information comes from the terminal device; or, the first indication information comes from a core network element in the core network equipment.

34. An apparatus, characterized in that, The device includes at least one processor coupled to a memory storing a program or instructions, the processor executing the program or instructions to cause the device to perform the method as described in any one of claims 1 to 32.

35. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 32.

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