Cell selection method, communication method, device, and system

Abstract

The present application relates to the technical field of communications, and discloses a cell selection method, a communication method, a device, and a system. The method comprises: in the case of camping on a first cell, receiving an NTN device list sent by a first NTN device, the first cell being a serving cell of the first NTN device, and the NTN device list comprising a device identifier of at least one NTN device in an NTN; and on the basis of device information of an NTN device among the at least one NTN device, performing cell selection based on stored information, so as to select a cell from among serving cells of the at least one NTN device, to camp on. In this way, the efficiency of cell search and selection is improved, and device power consumption is reduced. In addition, the cell selection method can ensure that a terminal device can search for and camp on a serving cell of an NTN device indicated by a network, and prevent the terminal device from searching for and camping on a serving cell that camps on an NTN device not indicated by the network, thereby ensuring the continuity and stability of network communication.

Description

Cell selection methods, communication methods, equipment and systems

[0001] This application claims priority to Chinese patent application filed on January 27, 2025, with application number 202510128817.5 and entitled "Cell Selection Method, Communication Method, Device and System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a cell selection method, communication method, device and system. Background Technology

[0003] Non-terrestrial networks (NTNs) are communication networks that do not rely entirely on traditional terrestrial infrastructure. They primarily utilize various non-terrestrial technologies and platforms (such as satellites, high-altitude platforms, drones, and underwater communication networks) to provide connectivity between terminal devices and the network. One of the most common forms of NTN networks is satellite communication. For example, terminal devices can reside in a satellite's serving cell (i.e., a TNT cell), with the satellite providing communication support for the terminal devices.

[0004] In an NTN network, when the location, coverage area, or service status of the satellite corresponding to the NTN cell on which a terminal device is camped changes, the terminal device needs to perform cell selection to re-camp on another NTN cell. Currently, terminal devices typically perform cell selection by executing initial cell selection. During initial cell selection, the terminal device needs to scan all its supported frequency bands to search for available NTN cells. For each cell found, the terminal device needs to measure its signal quality and then select a suitable cell to camp on based on the signal quality measurement results. Because this cell search and selection method requires scanning all frequency bands for cell search and measuring the signal quality of each available cell, it is inefficient and consumes a lot of power. Summary of the Invention

[0005] This application provides a cell selection method, communication method, device, and system, which can improve the efficiency of cell search and selection, reduce device power consumption, and avoid terminal devices searching for serving cells of NTN devices not indicated by the network, thereby improving the continuity and stability of network communication. The technical solution is as follows:

[0006] Firstly, a cell selection method is provided. This method can be executed by a terminal device, or by a component (such as a circuit, chip, or chip system) configured in the terminal device, or by a logic module or software capable of implementing all or part of the functions of the terminal device. This application does not limit the scope of this method. The following description uses a terminal device as an example.

[0007] The method includes: when a terminal device is camped in a first cell (the serving cell of a first NTN device), receiving an NTN device list sent by the first NTN device, the NTN device list including device identifiers of at least one NTN device in the NTN network; and performing cell selection based on stored information based on the device information of the at least one NTN device to select a cell from the serving cells of the at least one NTN device for camping.

[0008] The first NTN device can be any NTN device within the NTN network. NTN devices can be satellites or high-altitude platforms, etc. High-altitude platforms include drones, airships, hot air balloons, helicopters, or stratospheric balloons, etc. This application does not limit the specific form of the NTN device in its embodiments.

[0009] In this context, at least one NTN device in the NTN device list refers to the NTN device that the terminal device should connect to for continued network connectivity and data transmission, such as the NTN device that should be connected to for continued store-and-forward operations of signaling and user plane data. The device identifier of the NTN device is used to uniquely identify the corresponding NTN device and can be the name or ID of the NTN device, etc.

[0010] Here, device information refers to the device information required to perform cell selection based on stored information. For example, device information may include one or more of the following: service time, frequency information, and trajectory information for the corresponding NTN device. The service time of an NTN device refers to the duration for which it can provide effective service to users. The frequency of an NTN device refers to the specific frequency or frequency range used by the NTN device during communication. The trajectory information of the NTN device is used to indicate the movement trajectory and location information of the NTN device.

[0011] By receiving an NTN device list from the currently residing NTN device, and based on the device information of at least one NTN device included in the list, the terminal device performs cell selection based on stored information. This allows the terminal device to perform cell search and selection within the serving cell of that at least one NTN device, thereby improving the efficiency of cell search and selection and reducing device power consumption. Furthermore, this cell selection method ensures that the terminal device searches within the serving cell of the NTN device indicated by the network, avoiding searches within the serving cell of an NTN device not indicated by the network. This prevents problems such as the need to re-initiate the registration process due to searching within the serving cell of an NTN device not indicated by the network, thus improving the continuity and stability of network communication.

[0012] Optionally, before performing cell selection based on stored information based on the device information of the NTN devices in at least one NTN device, the terminal device further includes: obtaining the device information of the NTN devices in the at least one NTN device. For example, the device information of all or some of the NTN devices in the at least one NTN device can be obtained to perform cell selection based on stored information.

[0013] Optionally, obtaining the device information of the NTN devices in the at least one NTN device includes: determining the device information of all or some of the NTN devices in the at least one NTN device based on received system information and / or a first device information request sent to the first NTN device. The first system information includes first system information broadcast by the first NTN device, and the first device information request carries the device identifier of a first target NTN device for requesting the device information of the first target NTN device. The first target NTN device includes all or some of the NTN devices in the at least one NTN device.

[0014] In this way, the device information of NTN devices in the NTN device list can be obtained by combining the first system information and device information request broadcast by the NTN device, which improves the efficiency and flexibility of obtaining the device information of NTN devices.

[0015] Optionally, based on the received system information and / or the first device information request sent to the first NTN device, determining the device information of all or part of the NTN devices in at least one NTN device includes: if the system information contains device information of all devices in at least one NTN device, then obtaining the device information of all devices in at least one NTN device from the first system information. If the system information contains device information of part of the devices in at least one NTN device, then obtaining the device information of a first part of the devices from the system information, where the first part of the devices refers to the part of the NTN devices whose corresponding device information exists in the first system information; sending the first device information request to the first NTN device, the first device information request carrying the device identifier of the NTN devices in the second part of the devices, where the second part of the devices refers to the NTN devices in at least one NTN device other than the first part of the devices; receiving the device information of the NTN devices in the second part of the devices sent by the first NTN device. If the system information does not contain device information of any NTN device in at least one NTN device, then sending the first device information request to the first NTN device, the first device information request carrying the device identifier of the NTN devices in at least one NTN device; receiving the device information of the NTN devices in at least one NTN device sent by the first NTN device.

[0016] Thus, after receiving the NTN device list, the terminal device can first match the NTN device list with the received first system information to determine whether the device information for each NTN device in the NTN device list exists in the first system information. If the first system information contains device information for all NTN devices in the NTN device list, then the device information for each NTN device in the NTN device list is retrieved from the first system information. If the first system information does not contain device information for any NTN device in the NTN device list, or only contains device information for some NTN devices, then a first device information request is sent to the first NTN device to request the device information for the required NTN devices.

[0017] Optionally, the system information may also include first system information broadcast by at least one second NTN device, wherein at least one second NTN device refers to the NTN device corresponding to the NTN cell in which the terminal device camped before camping on the first cell.

[0018] In this way, based on the first system information broadcast by other NTN devices, the device information of NTN devices in the NTN device list can be obtained, thereby further improving the efficiency and flexibility of obtaining NTN device information.

[0019] Optionally, sending a first device information request to the first NTN device includes: sending a Radio Resource Control (RRC) reconfiguration request message to the first NTN device, wherein the RRC reconfiguration request message carries the first device information request.

[0020] Accordingly, receiving device information of NTN devices in the second part of the device sent by the first NTN device includes: receiving second system information sent by the first NTN device, wherein the second system information carries device information of NTN devices in the second part of the device. Receiving device information of at least one NTN device sent by the first NTN device includes: receiving second system information sent by the first NTN device, wherein the second system information carries device information of at least one NTN device.

[0021] This improves the flexibility of sending first device information requests and receiving device information.

[0022] Optionally, the first device information request includes the requested SIB type and the device identifiers of all or some of the devices in at least one NTN device, and the second system information is the SIB information corresponding to the SIB type, wherein the SIB type includes at least SIB32.

[0023] In this way, the terminal device can obtain device information by requesting SIB information from the first NTN device, which further improves the efficiency and flexibility of sending the first device information request and obtaining device information.

[0024] Optionally, the first system information is SIB information, and the SIB information includes at least SIB32 information.

[0025] Optionally, when the device information includes frequency point information, the method further includes: storing the frequency point information of at least one NTN device in an auxiliary information set of the terminal device, wherein the auxiliary information set includes acquired database or stored information. For example, storing the frequency point information of all or part of the NTN devices in at least one NTN device in the auxiliary information set of the terminal device.

[0026] This facilitates the terminal device to perform cell search and selection based on the frequency information of the NTN device in the at least one NTN device, which can speed up cell search efficiency and help to quickly find and camp on a suitable cell.

[0027] Optionally, based on the device information of the NTN devices in at least one NTN device, cell selection based on stored information is performed, including: whenever it is determined based on the device information of the NTN devices in at least one NTN device that any one of the at least one NTN devices has arrived within the coverage area of ​​the terminal device and is providing normal service, cell selection based on stored information is performed to perform cell search; if a second cell is found, the user camps on the second cell, the second cell being the serving cell of a third NTN device, and the third NTN device being any one of the at least one NTN devices.

[0028] In this way, the terminal device can decide whether to hibernate or start cell search based on the device information of the at least one NTN device, that is, decide when to hibernate and when to start cell search, so as to start cell search at the appropriate time and save device power consumption.

[0029] Optionally, the terminal device may determine, based on the trajectory information of the NTN device and the location information of the terminal device, that an NTN device has arrived or is about to arrive within the coverage area of ​​the terminal device, and if the NTN device can provide normal service based on its service time, perform cell search based on the frequency information of the NTN device. That is, it may attempt to search for the serving cell of the NTN device by scanning its frequency. If the serving cell of the NTN device is found, the terminal device may camp on the serving cell to establish a preliminary communication connection with the serving cell.

[0030] Optionally, if a second cell is found, after camping on the second cell, the terminal device can also establish a connection with a third NTN device. After successfully establishing a connection with the third NTN device, the terminal device can receive downlink information sent by the third NTN device and send uplink information to the third NTN device. The downlink information includes downlink signaling and / or downlink data, and the uplink information includes uplink signaling and / or uplink data.

[0031] In this way, after residing in the second cell, it can complete the reception of downlink information and the transmission of uplink information.

[0032] For example, a terminal device can initiate a random access request to the third NTN device corresponding to the second cell and establish uplink synchronization with the third NTN device to successfully access the second cell. After successfully accessing the second cell, the terminal device can receive downlink information sent by the third NTN device and can also send uplink information to the third NTN device.

[0033] Optionally, the terminal device receiving the NTN device list sent by the first NTN device includes: the terminal device receiving NAS signaling sent by the first NTN device, wherein the NAS signaling carries the NTN device list.

[0034] In other words, the first NTN device can send the NTN device list to the terminal device through NAS signaling, which can improve the flexibility of the NTN device in sending the NTN device list to the terminal device.

[0035] Optionally, receiving the NTN device list sent by the first NTN device includes: receiving a registration rejection message sent by the first NTN device after sending a registration request to the first NTN device, the registration rejection message carrying the NTN device list; or, receiving a connection release notification sent by the first NTN device, the connection release notification carrying the NTN device list.

[0036] In this way, when the location, coverage area, or service status of the first NTN device changes, such as when it is about to leave the coverage area of ​​the terminal device or is unable to continue providing services to the terminal device, it can send an NTN device list to the terminal device to inform the terminal device under which NTN devices it can continue its network connection and data transmission, so as to ensure the continuity and stability of communication.

[0037] Optionally, the first NTN device may be equipped with access network equipment and may also deploy all or part of the core network equipment functions, such as deploying all or part of the MME functions. For example, the first NTN device may be an NTN device in a Split MME architecture or an NTN device in a Full CN architecture. The embodiments of this application do not limit the specific network architecture of the NTN network to which the first NTN device belongs.

[0038] Secondly, a communication method is provided, which can be executed by a core network device, or by a component (such as a circuit, chip, or chip system) configured in the core network device, or by a logic module or software that can implement all or part of the functions of the core network device. This application does not limit the scope of the method.

[0039] The method includes sending an NTN device list to a terminal device residing in the serving cell of a first NTN device. The NTN device list includes device identifiers of at least one NTN device in the NTN network, so that the terminal device performs cell selection based on stored information based on the device information of the NTN device in the at least one NTN device. The device information refers to the device information required to perform cell selection based on stored information.

[0040] By sending an NTN device list to the terminal device, the terminal device can perform cell selection based on stored information, using the device information of at least one NTN device included in the NTN device list. This allows the terminal device to perform cell search and selection within the serving cell of that at least one NTN device, thereby improving the efficiency of cell search and selection and reducing device power consumption. Furthermore, this cell selection method ensures that the terminal device searches for and stays within the serving cell of the NTN device indicated by the network, avoiding searches for serving cells of NTN devices not indicated by the network. This prevents problems such as the need to re-initiate the registration process that might occur due to searching for serving cells of NTN devices not indicated by the network, thus improving the continuity and stability of network communication.

[0041] Optionally, sending an NTN device list to a terminal device residing in the first NTN device includes sending NAS signaling to the terminal device, wherein the NAS signaling carries the NTN device list.

[0042] In other words, core network devices can send NTN device lists to terminal devices via NAS signaling, which improves the flexibility of NTN devices in sending NTN device lists to terminal devices.

[0043] Optionally, the core network device can also receive a second device information request sent by the access network device. The second device information request carries the device identifier of a second target NTN device, which includes all or some of the devices in at least one NTN device. The device identifier of the NTN device in the second target NTN device is sent to the access network device.

[0044] This helps access network devices obtain the required NTN device information through a second device information request, improving the efficiency and flexibility of access network devices in obtaining NTN device information.

[0045] Thirdly, a communication method is provided. This method can be executed by an access network device, or by a component (such as a circuit, chip, or chip system) configured in the access network device, or by a logic module or software capable of implementing all or part of the functions of the access network device. This application does not limit the scope of this method. The following description uses the example of the access network device being deployed on a first NTN device.

[0046] The method includes: sending an NTN device list to a terminal device residing in the serving cell of a first NTN device, the NTN device list including device identifiers of at least one NTN device in the NTN network; receiving a first device information request sent by the terminal device, the first device information request carrying a device identifier of a first target NTN device, the first target NTN device including all or part of the devices of at least one NTN device; and sending device information of the NTN devices in the first target NTN device to the terminal device.

[0047] This helps terminal devices obtain the device information of the required NTN devices in the NTN device list through the first device information request, improving the efficiency and flexibility of terminal devices in obtaining NTN device information.

[0048] Optionally, receiving a first device information request sent by a terminal device includes: receiving a Radio Resource Control (RRC) reconfiguration request message sent by the terminal device, wherein the RRC reconfiguration request message carries the first device information request; sending device information of a first target NTN device to the terminal device includes: sending second system information to the terminal device, wherein the second system information carries the device information of the NTN device in the first target NTN device.

[0049] Optionally, the first device information request includes the system information block (SIB) type to be obtained and the device identifier of the first target NTN device, and the second system information is the SIB information corresponding to the SIB type, wherein the SIB type includes at least SIB32.

[0050] This improves the flexibility of terminal devices in sending first device information requests and receiving device information.

[0051] Optionally, after receiving the first device information request sent by the terminal device, the method further includes: obtaining the device information of the NTN devices in the first target NTN device based on the stored device information and / or the second device information request sent to the core network device; wherein the second device information request carries the device information of all or part of the devices in the first target NTN device.

[0052] In this way, the device information of NTN devices in the NTN device list requested by the terminal device can be obtained by combining the stored device information and the second device information request.

[0053] Optionally, obtaining device information of NTN devices in the first target NTN device based on stored device information and / or a second device information request sent to the core network device includes: if the stored device information includes device information of all devices in the first target NTN device, obtaining device information of all devices in the first target NTN device from the stored device information; if the stored device information includes device information of some devices in the first target NTN device, obtaining device information of some devices from the stored device information; sending a second device information request to the core network device, the second device information request carrying device identifiers of NTN devices in the remaining part of the first target NTN device; receiving device information of NTN devices in the remaining part of the device sent by the core network device; if the stored device information does not include device information of any device in the first target NTN device, sending a second device information request to the core network device, the second device information request carrying device identifiers of NTN devices in the first target NTN device; and receiving device information of NTN devices in the first target NTN device sent by the core network device.

[0054] Thus, after receiving the first device information request from the terminal device, the access network device can first match the first target NTN device carried in the first device information request with the stored device information to determine whether the stored device information contains device information for each NTN device in the first target NTN device. If the stored device information contains device information for all NTN devices in the first target NTN device, then the device information for all NTN devices in the first target NTN device is retrieved from the stored device information. If the stored device information does not contain device information for any NTN device in the first target NTN device, or only contains device information for some NTN devices, then a second device information request is sent to the core network device to request the device information for the required NTN devices.

[0055] Optionally, the method further includes: broadcasting first system information. The first system information is SIB information, which includes at least SIB32 information.

[0056] This makes it easier for terminal devices to obtain device information of NTN devices in the NTN device list based on the first system information, thereby improving the efficiency and flexibility of terminal devices in obtaining device information.

[0057] Fourthly, 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 of the possible implementations of the first, second, or third aspects described above. Optionally, the communication device further includes a memory.

[0058] Fifthly, a network system is provided, including the aforementioned terminal device and NTN device. Optionally, the communication system may further include other devices that communicate with the terminal device and / or the NTN device.

[0059] In a sixth aspect, a network system is provided, the network system including one or more of a first communication device, a second communication device, and a third communication device, wherein the first communication device is used to execute the method in any possible implementation of the first aspect, the second communication device is used to execute the method in any possible implementation of the second aspect, and the third communication device is used to execute the method in any possible implementation of the third aspect.

[0060] In a seventh aspect, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions), which, when the computer program is run, causes a computer to perform a method in any possible implementation of any of the above aspects.

[0061] Eighthly, 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.

[0062] Ninthly, 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.

[0063] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data. Attached Figure Description

[0064] Figure 1 is a schematic diagram of several NTN network systems provided in the embodiments of this application;

[0065] Figure 2 is a schematic diagram of a Split MME architecture provided in an embodiment of this application;

[0066] Figure 3 is a schematic diagram of a Full CN architecture provided in an embodiment of this application;

[0067] Figure 4 is a schematic flowchart of a cell selection method provided in an embodiment of this application;

[0068] Figure 5 is a schematic flowchart of a cell selection method in a satellite communication system provided in an embodiment of this application;

[0069] Figure 6 is a schematic block diagram of a communication device provided in an embodiment of this application;

[0070] Figure 7 is a schematic block diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0071] In the embodiments of this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of this application, and in the various implementation methods / methods / implementations within each embodiment, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the various implementation methods / methods / implementations within each embodiment are consistent and can be mutually referenced. The technical features in different embodiments and the various implementation methods / methods / implementations within each embodiment can be combined according to their inherent logical relationships to form new embodiments, implementation methods, methods, or implementation approaches. The embodiments of this application described below do not constitute a limitation on the scope of protection of this application.

[0072] In this application embodiment, "sending information to...(terminal)" can be understood as the destination of the information being the terminal, and may include sending information to the terminal directly or indirectly. "Receiving information from...(terminal)" can be understood as the source of the information being the terminal, and may include receiving information from the terminal directly or indirectly. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood in a similar way, and will not be elaborated further here.

[0073] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0074] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0075] The technical solutions of this application embodiment can be applied to various communication systems, such as: Global System for Mobile Communication (GSM) system, Code Division Multiple Access (CDMA) system, Wide Band Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, future 5th generation (5G) systems, or new radio (NR), etc.

[0076] In this application, the terminal device can refer to user equipment (UE), station, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile terminal (MT), mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment. The terminal device can also be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, large screen, in-vehicle device, wearable device, terminal device in a 5G network, or terminal device in a future evolved public land mobile network (PLMN), etc. This application does not limit the scope of the terminal device to these specific types.

[0077] For example, terminal devices can be Internet of Things (IoT) devices (e.g., sensors, electricity meters, water meters, etc.), V2X devices, stations (STs) in wireless local area networks (WLANs), cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistant (PDA) devices, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices (also known as wearable smart devices), tablets or computers with wireless transceiver capabilities, virtual reality (VR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes. Wireless terminals in the home, vehicle terminals, vehicles with vehicle-to-vehicle (V2V) communication capabilities, intelligent connected vehicles, drones with drone-to-drone (UAV-to-UAV, U2U) communication capabilities, etc.

[0078] In this embodiment, the terminal device or network device includes a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on top of the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through processes, such as Linux, Unix, Android, iOS, or Windows. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. Furthermore, this embodiment does not specifically limit the structure of the execution entity of the method provided in this embodiment, as long as it can communicate according to the method provided in this embodiment by running a program that records the code of the method provided in this embodiment.

[0079] Furthermore, various aspects or features of this application can be implemented as methods, apparatus, or articles of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used herein encompasses a computer program accessible from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical discs (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memory (EPROMs), cards, sticks, or key drives, etc.). Additionally, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0080] To facilitate understanding of this application, the communication system involved in the embodiments of this application will be described first.

[0081] The method provided in this application is applicable to NTN network systems. With the development of information technology, there are increasingly urgent requirements for efficient, mobile, and diverse communication. Currently, a key development area in the field of communication systems is global mobile communication (GSM), and an important component of GSM is NTN communication. NTN refers to a communication network that does not rely entirely on traditional terrestrial infrastructure, but primarily utilizes non-terrestrial communication infrastructure such as satellites and high-altitude platforms (e.g., drones, helicopters) to achieve global communication coverage.

[0082] Typical NTN communication is satellite communication. In important fields such as space communication, aviation communication, and maritime communication, satellites play an irreplaceable role. Satellite communication features long communication distances, large coverage areas, and flexible networking capabilities, providing services to both fixed and various mobile terminals. Satellites are classified according to their orbital altitude into low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites, geostationary earth orbit (GEO) satellites, and highly elliptical orbit (HEO) satellites. Besides satellites, NTN can also include high altitude platforms (HAPs) (such as unmanned aircraft systems (UAS), airships, hot air balloons, helicopters, and stratospheric balloons).

[0083] In the embodiments of this application, the NTN can be a 4G-based NTN, a 5G-based NTN, an NR-based NTN, an Internet of Things (IoT)-based NTN, a narrowband Internet of Things (NB-IoT)-based NTN, or an NTN based on other current technologies or other technologies that may emerge in the future.

[0084] Compared to traditional terrestrial networks, NTN utilizes NTN equipment (such as typical satellites) in its network deployment. For example, access network equipment can be deployed on NTN equipment to provide coverage for terminal devices. Alternatively, access network equipment can be deployed on NTN equipment, along with all or part of the core network equipment's functionality, to provide coverage for terminal devices. Or, NTN equipment can be used as a relay to forward signals from terrestrial access network equipment to provide coverage for terminal devices.

[0085] In other words, the NTN network system in this application embodiment includes terminal equipment and NTN equipment, with access network equipment deployed on the NTN equipment. The access network equipment is connected to the core network. The core network equipment may or may not be deployed on the NTN equipment; this application embodiment does not limit this. For example, all or part of the functions of the core network equipment may be deployed on the NTN equipment. For instance, some functions of the split mobility management entity (MME) in the core network equipment may be deployed on the NTN equipment. Additionally, the NTN communication system may also include ground stations. A ground station refers to ground equipment located on Earth for space communication. NTN equipment can communicate with ground networks through ground stations.

[0086] Alternatively, in other words, the NTN network system in this application embodiment includes terminal equipment, access network equipment, and core network equipment. The access network equipment is deployed on the NTN equipment. The core network equipment may or may not be deployed on the NTN equipment. For example, all or part of the functions of the core network equipment are deployed on the NTN equipment. For instance, a portion of the functions of the MME in the core network equipment are deployed on the NTN equipment, while another portion of the functions are deployed on the ground.

[0087] It should be noted that, in addition to typical satellites, the NTN devices in this application embodiment may also include high-altitude platforms or underwater communication equipment, etc., and this application embodiment does not limit the specific form of the NTN device. For ease of explanation, the following embodiments use satellites as examples.

[0088] Next, the NTN network system involved in the embodiments of this application will be illustrated with reference to the accompanying drawings. Please refer to Figure 1, which is a schematic diagram of several NTN network systems provided in the embodiments of this application.

[0089] As shown in Figure 1(a), the NTN network system includes terminal device 101, NTN device 102, and terrestrial network 103. Access network equipment is deployed on NTN device 102, and terrestrial network 103 includes core network equipment and other terrestrial network equipment. Terminal device 101 can access the network via an air interface, for example, communicating with the access network equipment via a Uu interface. Access network equipment can connect to core network equipment via wireless links, for example, communicating with the core network equipment in terrestrial network 103 via a ground station. Core network equipment can connect to other terrestrial network equipment via wireless links, for example, communicating with other terrestrial network equipment via other PLMS and networks. Simultaneously, wireless links also exist between NTN devices for signaling interaction and user data transmission between NTN devices.

[0090] As shown in Figure 1(b), the NTN network system includes terminal device 101, NTN device 102, and terrestrial network 103. NTN device 102 deploys access network equipment and some functions of core network equipment. Terrestrial network 103 includes other functions of the core network equipment and other network equipment. Access network equipment can connect to some functions of the core network equipment deployed on the NTN device via wired or wireless means, for example, through relevant interfaces. Some functions of the core network equipment deployed on the NTN device can connect to other functions deployed on the ground via wireless links, for example, through ground stations. Other functions of the core network equipment deployed on the ground can connect to other terrestrial network equipment via wireless links, for example, through other PLMS and networks.

[0091] As shown in Figure 1(c), the NTN network system includes terminal device 101, NTN device 102, and terrestrial network 103. NTN device 102 is equipped with all the functions of access network equipment and core network equipment. Access network equipment can be connected to core network equipment via wired or wireless means. Core network equipment is connected to terrestrial network 103 via a wireless link, for example, through a ground station.

[0092] In one embodiment, the NTN network in this application can be an NTN store-and-forward network. An NTN store-and-forward network refers to a data transmission network that introduces a store-and-forward mechanism on top of NTN. The core idea of ​​an NTN store-and-forward network is to first store data at intermediate nodes of the NTN network (such as satellites or high-altitude platforms) and then forward it. This mechanism can effectively cope with situations where the feeder link between NTN equipment and the terrestrial network is disconnected or the inter-land link is unstable, ensuring that user data can be correctly transmitted after the link is restored.

[0093] For example, the working principle of an NTN store-and-forward network can include the following steps: 1) Receiving data: When data arrives at a node in a non-terrestrial network (such as a satellite), the node first receives and stores the data. 2) Checking data: The node checks the received data to ensure its integrity and correctness. If the data is incorrect, the node requests a retransmission. 3) Forwarding data: Once the data is verified to be correct, the node determines the optimal forwarding path based on information such as ephemeris and satellite payload, and forwards the data to the next destination until the data finally reaches its destination.

[0094] In one embodiment, the NTN network may include two network architectures: Split MME and Full Core Network (Full CN). These two network architectures will be described separately below.

[0095] 1. Split MME architecture.

[0096] The Split MME architecture is a network architecture that divides the functions of the MME into multiple parts. In NTN networks, the Split MME architecture separates the functions of the MME, deploying some functions (such as communication with satellites and data processing) on ​​satellites or specific satellite communication nodes, while the remaining functions (such as signaling processing and control) are retained on the terrestrial network.

[0097] For example, Figure 2 is a schematic diagram of a Split MME architecture provided in an embodiment of this application. The architecture shown in Figure 2 integrates satellite communication technology and LTE communication technology. As shown in Figure 2, the Split MME architecture may include: a terminal device 201, a satellite 202, and a terrestrial network 203. Part of the MME's functions are deployed on the satellite 202 (i.e., MME-onboard), and another part of its functions are deployed on the terrestrial network 203 (i.e., MME-ground). MME-onboard and MME-ground each undertake different functions in the Split MME architecture, jointly realizing the mobility management and session management of the terminal device.

[0098] Terminal device 201 can access the network via an air interface, such as through a Uu interface. Satellite 202 is equipped with access network equipment and an MME-onboard. The access network equipment and MME-onboard can be connected via wired or wireless means; for example, the access network equipment can connect to the MME-onboard via an S1 interface (such as an S1-MME). The MME-onboard and MME-ground can be connected via a wireless link. The MME-ground can also be connected to other network elements of the terrestrial network via a wireless link. Simultaneously, wireless links (such as inter-satellite links or feeder links) exist between satellites for signaling interaction and user data transmission between satellites.

[0099] Terminal device 201 refers to a mobile device with wireless transceiver capabilities. For example, terminal device 201 can be a mobile device such as a smartphone, smartwatch, or tablet computer, or any of the terminal devices mentioned above. Terminal device 201 can access the satellite network via the air interface and initiate services such as making calls and accessing the internet.

[0100] Satellite 202 serves as a non-terrestrial base station (gNB) or relay node, enabling wireless communication with terminal devices and initial mobility management. Access network equipment and an MME-onboard are deployed on Satellite 202.

[0101] The access network equipment primarily provides radio access services, such as scheduling radio resources to access terminals, and can also provide mobility management support for the MME. For example, as shown in Figure 2, this access network equipment can be the evolved UMTS terrestrial radio access network (E-UTRAN).

[0102] The MME-onboard is primarily responsible for initial mobility management. For example, it manages wireless connections with terminal devices, including signaling interaction and data transmission; assists with initial location updates and authentication of terminal devices; and maintains communication with the MME-ground to jointly achieve mobility and session management for terminal devices.

[0103] The terrestrial network 203 includes the MME-ground and other terrestrial network elements. For example, the terrestrial network 203 includes the MME-ground, the core network, and other terrestrial network elements. The MME-ground is mainly responsible for interacting with the core network and other terrestrial network elements, as well as performing more complex mobility management and session management functions.

[0104] As shown in Figure 2, other terrestrial network elements may include a Serving Gateway (SGW), a Packet Data Network Gateway (PGW), and a Home Subscriber Server (HSS). The SGW is primarily used for packet routing and forwarding. The PGW's main functions include user-based packet filtering, lawful interception, and IP address allocation. The HSS stores user subscription information, user subscription data, and mobile user location information. Additionally, as shown in Figure 2, other terrestrial network elements may also include a Short Message Service Gateway Mobile Services Switching Center (SMS-GMSC) / Interworking Mobile Services Switching Center (IW MSC) / SMS Router, an Interworking Function-Service Capability Exposure Function (IWF-SCEF) / Service Capability Exposure Function (SCEF), a Policy and Charging Rules Function (PCRF), a Data Network (DN), and Cellular IoT Services (CIot services).

[0105] The aforementioned different ground network elements can be connected through relevant interfaces or gateways. For example, the MME-ground and SGW can be connected through the S11 interface. The SGW and PGW can be connected through the S5 / S8 interface. The MME-ground and HSS can be connected through the S6a interface. The connection methods between other network elements will not be described in detail in this embodiment.

[0106] It should be noted that the Split MME architecture shown in Figure 2 is only an example of a satellite communication scenario. It should be understood that satellite 102 can also be other NTN devices, such as high-altitude platforms or unmanned aerial vehicle systems.

[0107] 2. Full CN architecture.

[0108] Full CN architecture is a network architecture that integrates all core network functions onto one or more nodes. In the Full CN architecture of an NTN network, all core network elements are deployed on satellites. Because all core network functions are integrated, this architecture typically offers higher integration and lower latency.

[0109] For example, Figure 3 is a schematic diagram of a Full CN architecture provided in an embodiment of this application. The architecture shown in Figure 3 integrates satellite communication technology and 5G communication technology. As shown in Figure 3, the Full CN architecture may include: terminal device 301, satellite 302, ground station 303, and remote endpoint 304. All network elements of the core network are deployed on satellite 302.

[0110] When satellite 302 moves to location L1, terminal device 301 is within the coverage area of ​​satellite 302, and satellite 302 can provide services to terminal device 301. Terminal device 301 can access satellite 302 via an air interface, such as via a Uu interface. After accessing satellite 302, terminal device 301 can interact with the core network deployed on satellite 302 for mobile-originating (MO) / mobile-terminated (MT) data and signaling. For example, satellite 302 can receive and store uplink signaling and data sent by terminal device 101. When satellite 302 moves to location L2, satellite 302 can connect to ground station 303 via a wireless link (such as a feeder link), and ground station 303 can connect to remote endpoint 304 via a wireless link. Satellite 302 can interact with remote endpoint 304 via ground station 303 to exchange Mobile Initiation (MO) / Mobile Termination (MT) data and signaling. For example, satellite 302 can forward uplink signaling and data from terminal device 101 to ground station 303, and then ground station 303 can forward it to remote endpoint 304 for processing, thereby realizing store-and-forward function.

[0111] In the aforementioned Split MME and Full CN network architectures, terminal devices can reside in and access NTN cells for network communication. NTN cells, or non-terrestrial network cells, differ from traditional terrestrial cellular network cells in that they provide communication services via NTN equipment such as satellites. For example, an NTN cell is established by the ground area pointed to by a satellite beam. The coverage location of an NTN cell can be fixed or change as the satellite moves.

[0112] In an NTN network, when the location, coverage area, or service status of the satellite corresponding to the NTN cell where a terminal device is camped changes, the terminal device needs to perform cell search and cell selection in order to camp on other NTN cells.

[0113] Currently, terminal devices typically perform cell selection by executing initial cell selection. During this process, the terminal device needs to scan all supported frequency bands to search for available NTN cells. For each cell found, the terminal device needs to measure its signal quality and then select a suitable cell to camp on based on the signal quality measurement results. Because initial cell selection requires scanning all frequency bands for cell search and measuring the signal quality of each available cell, this cell search and selection method is inefficient, consumes a lot of power, and the cells searched and selected may not meet the terminal device's communication requirements.

[0114] In this embodiment of the application, to improve the efficiency of cell search and selection in the NTN network and reduce device power consumption, an improved cell selection method is proposed. Using this method, after a terminal device camps on a first cell (the serving cell of a first NTN device), it can receive an NTN device list sent by the first NTN device. This NTN device list includes the device identifiers of at least one NTN device in the NTN network. Subsequently, the terminal device can perform stored information cell selection based on the device information of the NTN devices in the NTN device list to select a cell from the serving cells of the at least one NTN device to camp on.

[0115] The NTN device list includes at least one NTN device that the terminal device should connect to to maintain network connectivity and data transmission, such as the NTN device to which it should connect to continue store-and-forward operations for signaling and user plane data. For example, in a satellite communication scenario, the NTN device list can be a satellite ID list, which includes the satellite IDs of at least one satellite in the NTN network. This NTN device list can be determined by the core network.

[0116] The device information of the NTN device refers to the device information required to perform cell selection based on stored information. For example, the device information may include one or more of the NTN device's service time, frequency information, and ephemeris information, and may also include other device information such as coverage information. This application embodiment does not limit this.

[0117] By performing cell selection based on stored information from at least one NTN device in the NTN device list, the terminal device can perform cell search and selection within the serving cell of that at least one NTN device. This improves the efficiency of cell search and selection and reduces device power consumption. Furthermore, this cell selection method ensures that the terminal device searches for and resides within the serving cell of the NTN device indicated by the network, avoiding searches for serving cells of NTN devices not indicated by the network. This prevents problems such as the need to re-initiate the registration process due to searching for serving cells of NTN devices not indicated by the network, thus improving the continuity and stability of network communication.

[0118] Next, the cell selection method provided in the embodiments of this application will be described by way of example, in conjunction with the Split MME architecture and Full CN architecture described above.

[0119] In the Split MME architecture, when a UE needs to communicate with the core network, its signaling is transmitted via satellite to the ground-based MME (MME-ground) for processing. Based on ephemeris data, satellite payload information, and other information, the MME-ground can determine which satellites will be used to continue communication with the UE and accordingly transfer the UE's downlink data to those satellites. This allows data to be efficiently transmitted to the UE via the satellite network. Furthermore, after determining the communication path, the MME-ground can provide the UE with a satellite ID list during the Attach / Tracking Area Update (TAU) process, allowing the UE to attempt Attach / TAU based on this list.

[0120] In the Full CN architecture, when a UE needs to communicate with the core network, the core network can determine which satellites will be used to continue communicating with the UE based on information such as ephemeris and satellite load, and directly transfer the UE's downlink data to these satellites for transmission. Additionally, the MME in the core network can provide the UE with a satellite ID list during the Attach / TAU process. The UE can use satellites in the satellite ID list to interact with the core network for Mobility Initiation (MO) / Mobility Termination (MT) data and signaling.

[0121] As shown above, under NTN network architectures such as the Split MME architecture and the Full CN architecture, the core network determines which satellites will continue to communicate with the UE based on information such as ephemeris and load, and forwards the UE's downlink data to these satellites accordingly. After determining the communication path, the currently serving satellite can provide the UE with a satellite ID list. This satellite ID list indicates which satellites the UE should connect to in the coming period to continue completing signaling and user plane data store-and-forward operations. In other words, this list provides the UE with clear guidance on which satellites it can maintain its network connection and data transmission. The UE can switch and connect to different satellites based on the satellite ID list to ensure the continuity and stability of communication.

[0122] However, how the UE can search for and select satellite cells (serving cells of satellites) based on the satellite ID list and avoid camping on satellite cells not indicated by the network has become an urgent problem to be solved.

[0123] In this embodiment of the application, after receiving the satellite ID list sent by the serving satellite, cell selection based on stored information is performed based on the satellite information of the satellites in the satellite ID list. This ensures that the UE can efficiently search for and select the serving cell of the satellite in the satellite ID list for camping, thereby avoiding searching for and camping in satellite cells not indicated by the network, and improving the reliability of cell camping and network communication.

[0124] It should be noted that the embodiments of this application are only examples of the Split MME structure and the Full CN architecture. It should be understood that the NTN network in the embodiments of this application can also be implemented using other network architectures. The embodiments of this application do not limit the specific architecture of the NTN network.

[0125] The cell selection method provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0126] Figure 4 is a schematic flowchart of a cell selection method provided in an embodiment of this application. The execution subjects of this method include a terminal device and a first NTN device. As an example and not a limitation, the execution subjects of the method can also be chips applied in the terminal device or the first NTN device. This method can be applied to the NTN network shown in Figure 1 or Figure 2 above. As shown in Figure 4, the method includes the following steps:

[0127] S401. When the terminal device is camped in the first cell, the first NTN device sends an NTN device list to the terminal device. The NTN device list includes the device identifier of at least one NTN device in the NTN network.

[0128] The first cell is an NTN cell and serves as the cell for the first NTN device.

[0129] The first NTN device can be any NTN device within the NTN network. NTN devices can be satellites or high-altitude platforms, etc. High-altitude platforms include drones, airships, hot air balloons, helicopters, or stratospheric balloons, etc. This application does not limit the specific form of the NTN device in its embodiments.

[0130] In this context, at least one NTN device in the NTN device list refers to the NTN device that the terminal device should connect to for continued network connectivity and data transmission, such as the NTN device that should be connected to for continued store-and-forward operations of signaling and user plane data. The device identifier of the NTN device is used to uniquely identify the corresponding NTN device and can be the NTN device's name or identity number (ID), etc.

[0131] In one embodiment, when the location, coverage area, or service status of the first NTN device changes, such as when it is about to leave the coverage area of ​​the terminal device or is unable to continue providing services to the terminal device, the first NTN device can send an NTN device list to the terminal device to inform the terminal device under which NTN devices it can continue its network connection and data transmission, so as to ensure the continuity and stability of communication.

[0132] In one embodiment, the first NTN device can send non-access stratum (NAS) signaling to the terminal device, which carries a list of NTN devices. That is, the first NTN device can send the list of NTN devices to the terminal device via NAS signaling.

[0133] As an example, the first NTN device may carry an NTN device list in the registration rejection message or connection release notification sent to the terminal device, so as to send the NTN device list to the terminal device through the registration rejection message or connection release notification.

[0134] For example, after receiving a registration request from another device, the first NTN device may send a registration rejection message to the first device, which carries a list of NTN devices.

[0135] For example, when the connection release conditions are met, the first NTN device can send a connection release notification to the first device, which carries a list of NTN devices.

[0136] It should be understood that the first NTN device may also send the NTN device list to the terminal device in other ways, and this application embodiment does not limit this.

[0137] In one embodiment, the NTN device list can be determined by a core network device. The core network device can send the NTN device list to the terminal device. For example, an access network device is deployed on the first NTN device. The core network device can send the NTN device list to the terminal device through the access network device. Accordingly, the terminal device can receive the NTN device list from the core network device sent by the access network device.

[0138] In one embodiment, the operation of sending the NTN device list performed by the access network device is essentially a transparent transmission, for example, sending the NTN device list to the terminal device by transparently transmitting NAS signaling from the core network device. During this process, the access network device is unaware of the NTN device list; it only performs the operation of transparently transmitting the NAS signaling to the terminal device.

[0139] In this configuration, core network equipment can be deployed outside the first NTN equipment, for example, on a terrestrial network. Alternatively, all or part of the core network equipment's functions can be deployed on the first NTN equipment. For example, in the Split MME architecture described above, some of the MME's functions in the core network equipment are deployed on the first NTN equipment, while other functions are deployed on the terrestrial network. As another example, in the Full CN architecture described above, all the functions of the core network equipment are deployed on the first NTN equipment.

[0140] In one embodiment, the first NTN device can determine the NTN device list based on information such as the load and trajectory of NTN devices in the NTN network, or it can determine the NTN device list in conjunction with other devices. For example, if an MME-onboard is deployed on the first NTN device, the MME-onboard can calculate the NTN device list together with the MME-ground of the terrestrial network. Alternatively, the first NTN device can obtain the NTN device list from other NTN devices or the terrestrial network. This application embodiment does not limit the method by which the first NTN device obtains the NTN device list.

[0141] In addition, while camped on the first cell, the terminal device can also receive downlink information forwarded by the first NTN device, and send uplink information to the first NTN device. The downlink information includes downlink signaling and / or downlink data. The uplink information includes uplink signaling and / or data.

[0142] After receiving uplink information from the terminal device, the first NTN device can also store or forward the uplink information. For example, the first NTN device can forward the uplink information from the terminal device to the terrestrial network for processing. Specifically, the first NTN device can forward the uplink information from the terminal device to the terrestrial network via an inter-satellite link or a feeder link.

[0143] S402. The terminal device obtains the device information of the NTN device among the at least one NTN device according to the NTN device list.

[0144] In this embodiment of the application, before the terminal device selects a cell based on the NTN device list, it can first obtain the device information of the NTN devices in the NTN device list, so as to select a cell based on the device information of the NTN devices in the NTN device list.

[0145] In one embodiment, the terminal device can obtain device information of all or some of the at least one NTN devices from the NTN device list, and perform cell selection based on the stored information based on the device information of all or some of the at least one NTN devices.

[0146] In this context, the device information of the NTN device refers to the device information required by the terminal device to perform cell selection based on stored information. For example, the device information of the NTN device includes one or more of the service time, frequency information, and trajectory information of the corresponding NTN device, and may also include other information such as coverage information. This application embodiment does not limit this. The service time, frequency information, and trajectory information of the NTN device are key elements of NTN communication. This information helps the terminal device determine whether it is within the coverage area of ​​the NTN device and whether the NTN device is providing normal service, and adjust its communication strategy accordingly.

[0147] The service time of an NTN device refers to the duration for which it can provide effective service to users. The frequency of an NTN device refers to the specific frequency or frequency range used by the NTN device during communication. The trajectory information of an NTN device indicates its movement trajectory and location. The coverage information of an NTN device indicates its coverage area and may include the longitude and latitude of a reference point, the elevation angles of the leftmost and rightmost points, and the distance (radius) from the reference point to the edge of the NTN device or the beam's coverage area.

[0148] For example, when the NTN device is a satellite, the satellite's trajectory information can be its ephemeris. A satellite's ephemeris is a mathematical expression or dataset used to describe its operational status in space, such as position and velocity, indicating its trajectory and position information. Ephemeris is a key component of satellite navigation and positioning systems, used to accurately calculate the satellite's position and time information.

[0149] In one embodiment, the terminal device may obtain device information of NTN devices in the NTN device list based on received system information and / or a first device information request sent to the first NTN device, such as obtaining device information of all or part of the devices in the NTN device list.

[0150] Thus, device information of NTN devices in the NTN device list can be obtained based on received system information, or by sending a first device information request to the first NTN device, or by combining the above two methods. Furthermore, the above methods can be used to obtain device information for all devices in the NTN device list, or for a portion of the devices; this application does not limit this approach.

[0151] The first device information request includes device information of the first target NTN device in the NTN device list, and is used to request the device information of the first target NTN device. The first target NTN device refers to the NTN device in the NTN device list for which device information needs to be requested, and may include all or some of the NTN devices in the NTN device list.

[0152] The system information received by the terminal device includes at least the first system information broadcast by the first NTN device, and may also include the first system information broadcast by at least one second NTN device. At least one second NTN device refers to the NTN device corresponding to the NTN cell in which the terminal device camped before camping on the first cell, i.e., the NTN device accessed before camping on the first cell.

[0153] For example, if the terminal device is camped on the serving cell of the second NTN device before camping on the first cell, it can receive the first system information broadcast by the second NTN device. Afterwards, after camping on the first cell, it can also receive the first system information broadcast by the first NTN device. Thus, the first system information received by the terminal device includes both the first system information broadcast by the first NTN device and the first system information broadcast by the second NTN device.

[0154] It should be noted that the first system information broadcast by the NTN device (first NTN device or second NTN device) refers to the first system information broadcast by the access network device deployed on the NTN device. The first system information broadcast by the access network device can be calculated by the access network device itself, obtained from the core network device, or obtained from other NTN devices. This application embodiment does not limit the source of the first system information broadcast by the access network device.

[0155] In one embodiment, the NTN device (such as the first NTN device) may broadcast first system information when it is necessary to provide the terminal device with NTN device assistance information for predicting discontinuous coverage, such as when the NTN device enters a new coverage area or when it needs to update the NTN device assistance information.

[0156] The first system information includes NTN device auxiliary information, which includes device information for one or more NTN devices. The device information for each NTN device includes its service time, frequency information, and trajectory information. The first system information can be system information block (SIB) information, such as SIB32 information.

[0157] In one embodiment, the terminal device can combine received system information with a first device information request sent to the first NTN device to obtain device information of NTN devices in the NTN device list. For example, after receiving the NTN device list, the terminal device can first match the NTN device list with the received system information to determine whether device information for each NTN device in the NTN device list exists in the system information. If device information for all NTN devices in the NTN device list exists in the system information, then the device information for all NTN devices in the NTN device list is obtained from the system information. If device information for any NTN device in the NTN device list does not exist in the system information, or only device information for some NTN devices exists, then the terminal device sends a first device information request to the first NTN device to request the device information of the required NTN devices.

[0158] In one embodiment, a terminal device can send a first device information request to a first NTN device via a radio resource control (RRC) reconfiguration request message to obtain the device information of the required NTN device. The RRC reconfiguration request message is used to request the reconfiguration of an established RRC connection. The RRC reconfiguration request message is also called an RRC connection reconfiguration request message.

[0159] For example, the terminal device can send an RRC reconfiguration request message to the first NTN device, and the RRC reconfiguration request message carries the first device information request.

[0160] In one embodiment, the RRC reconfiguration request message includes the requested SIB type and the device identifiers of all or some devices in the NTN device list, requesting the first NTN device to return the device information of all or some devices through the SIB information corresponding to the SIB type. The SIB type includes at least SIB32.

[0161] As an example, an RRC reconfiguration request message includes the following: RRC header, transaction ID, reconfiguration type, SIB information, and critical extensions. The RRC header contains the message type and other control information; the transaction ID is a unique identifier for the RRC transaction; the reconfiguration type indicates the type of reconfiguration, which can include addition, modification, or deletion; the SIB information is the specific SIB information request, typically including the required SIB type, such as SIB32; and the critical extensions are fields used to extend the message and can carry the device identifier of the NTN device.

[0162] As an example, a sample structure for an RRC reconfiguration request message can be shown below:

[0163] It should be understood that the message structure of the above RRC reconfiguration request message is only an example and does not constitute a limitation on the message structure of the RRC reconfiguration request message.

[0164] After receiving a first device information request from a terminal device, the first NTN device can obtain the device information of the corresponding NTN device based on the device identifier of the first target NTN device carried in the first device information request, and then send the obtained device information to the terminal device.

[0165] In one embodiment, the first NTN device may obtain device information of all NTN devices in the first target NTN device according to the first device information request, and send the device information of all NTN devices in the first target NTN device to the terminal device; alternatively, it may obtain device information of some NTN devices in the first target NTN device and send the device information of some NTN devices in the first target NTN device to the terminal device.

[0166] In one embodiment, the first NTN device can obtain the device information of the NTN devices in the first target NTN device from the stored device information, calculate the device information of these NTN devices based on the relevant information, obtain the device information of these NTN devices from other NTN devices through the wireless link between NTN devices, obtain the device information of these NTN devices from the core network device, or obtain the device information of these NTN devices by combining at least two of the above methods. The embodiments of this application do not limit the method by which the first NTN device requests to obtain device information based on the first device information.

[0167] In one embodiment, an access network device is deployed on the NTN device. The terminal device can send a first device information request to the access network device, the first device information request carrying the device identifier of a first target NTN device in the NTN device list. After receiving the first device information request, the access network device can obtain the device information of the NTN devices in the first target NTN device based on the stored device information and / or a second device information request sent to the core network device, and send the obtained device information to the terminal device. The second device information request carries the device information of all or some of the devices in the first target NTN device.

[0168] For example, if the stored device information includes device information for all devices in the first target NTN device, the device information for all devices in the first target NTN device can be obtained from the stored device information.

[0169] For example, if the stored device information includes device information of some devices in the first target NTN device, the device information of some devices is obtained from the stored device information; a second device information request is sent to the core network device, the second device information request carrying the device identifier of the NTN device in the remaining part of the first target NTN device; and the device information of the NTN device in the remaining part of the device is received from the core network device.

[0170] For example, if the stored device information does not include the device information of any of the first target NTN devices, a second device information request is sent to the core network device, carrying the device identifiers of the NTN devices in the first target NTN device; and the device information of the NTN devices in the first target NTN device is received from the core network device. Alternatively, a second device information request is sent to the core network device, carrying the device identifiers of all devices in the first target NTN device; and the device information of all or some of the NTN devices in the first target NTN device is received from the core network device.

[0171] In one embodiment, determining the device information of at least one NTN device based on received system information and / or a first device information request sent to the first NTN device may include the following possible scenarios:

[0172] 1) If the received system information contains device information for all devices in at least one NTN device, then obtain the device information for at least one NTN device from the first system information.

[0173] 2) If the received system information contains device information of at least some devices in at least one NTN device, then obtain the device information of the first part of the device from the first system information. The first part of the device refers to the part of the NTN devices whose corresponding device information exists in the first system information. Send a first device information request to the first NTN device. The first device information request carries the device identifier of the NTN device in the second part of the device. The second part of the device is the NTN device other than the first part of the device in at least one NTN device. Receive the device information of the NTN device in the second part of the device sent by the first NTN device.

[0174] 3) If the received system information does not contain device information for any NTN device among at least one NTN device, then send a first device information request to the first NTN device, the first device information request carrying the device identifier of the NTN device among at least one NTN device; and receive the device information of the NTN device among at least one NTN device sent by the first NTN device.

[0175] For example, a first device information request is sent to a first NTN device, the first device information request carrying the device identifiers of all devices in at least one NTN device; then, device information of all or part of the NTN devices in at least one NTN device is received from the first NTN device.

[0176] In one embodiment, after receiving a first device information request, the first NTN device can send device information of all or part of the NTN devices in the first target NTN device to the terminal device via second system information. For example, the first NTN device can send the second system information to the terminal device, which carries the device information of all or part of the NTN devices. For instance, the second system information can be system information block (SIB) information, such as SIB32 information.

[0177] As an example, if an RRC reconfiguration request message carrying a first device information request is received from a terminal, the first NTN device can send an RRC reconfiguration completion message to the terminal device. The RRC reconfiguration completion message carries second system information, which includes device information of all or part of the NTN devices in the first target NTN device.

[0178] Additionally, if the RRC reconfiguration request message also includes the requested SIB type, and the SIB type is SIB32, then an NTN device can send an RRC reconfiguration completion message to the terminal device. This RRC reconfiguration completion message carries SIB32 information, which includes device information of all or part of the NTN devices in the first target NTN device.

[0179] As an example, a sample structure for SIB32 information can be shown below, which includes the service time, frequency, and ephemeris of satellites with satellite IDs of satellite id-r17, satellite id-v1800, and satellite id-v1830.

[0180] It should be understood that the information structure of SIB32 information described above is merely an example and does not constitute a limitation on the information structure of SIB32 information.

[0181] It should be noted that in practical applications, after the terminal device sends a first device information request to the first NTN device, the first NTN device may respond to the first device information request and return device information of all devices in the first target NTN device to the terminal device, or it may only return device information of some devices in the first target NTN device to the terminal device, or it may fail to respond and not return device information of any device in the first target NTN device to the terminal device. This application embodiment does not limit the response result of the first NTN device after the terminal device sends the first device information request to the first NTN device. Based on this, the terminal device may obtain device information of all devices in the NTN device list, or it may obtain device information of some devices in the NTN device list, through the first system information and the first device information request. Regardless of whether it obtains device information of all devices in the NTN device list or only some devices, the terminal device can perform cell selection based on stored information based on the obtained device information.

[0182] S403. The terminal device performs cell selection based on the stored information based on the acquired device information.

[0183] The obtained device information includes device information for all or some of the NTN devices in the NTN device list.

[0184] Cell selection based on stored information refers to selecting a cell using previously stored relevant information. In this embodiment, the device information of NTN devices in the obtained NTN device list can be used to select a cell for camping, that is, the obtained device information is used as stored information to perform cell selection based on stored information.

[0185] This cell selection method speeds up the cell selection process because the terminal device can directly attempt to camp on the serving cell of at least one NTN device indicated by the network, without needing to perform a full search. This improves the efficiency of cell search and selection and reduces device power consumption. Furthermore, it avoids the terminal device camping on the serving cell of an NTN device not indicated by the network, thus preventing potential problems such as needing to re-initiate the registration process due to searching for a serving cell of an NTN device not indicated by the network. This improves the efficiency and reliability of cell camping and maintaining network connectivity.

[0186] In one embodiment, when the device information includes frequency information, the terminal device can store the acquired frequency information of the NTN device in the terminal device's auxiliary information set, i.e., add it to the terminal device's auxiliary information set. Then, when performing cell selection based on the stored information, cell search can be performed based on this NTN device frequency information, thereby accelerating cell search efficiency and helping to quickly find and camp on a suitable cell.

[0187] The auxiliary information set is used to store a series of key information for assisting terminal equipment in cell selection, which may include an acquisition database (AcqDb) or stored information.

[0188] In addition, the terminal device may also store other device information such as service time or trajectory information of each NTN device in the at least one NTN device into the auxiliary information set of the terminal device, which is not limited in this embodiment of the application.

[0189] In one embodiment, the terminal device can decide whether to hibernate or initiate cell search based on the acquired device information of the NTN devices and the location information of the terminal device, thereby saving power consumption. In other words, the terminal device can decide when to hibernate and when to initiate cell search based on the device information of these NTN devices and its own location information, thus enabling it to initiate cell search only at the appropriate time and save power consumption.

[0190] As an example, a terminal device may initiate cell selection based on stored information, provided that it determines, based on the acquired device information of the NTN device, that any of the at least one NTN device is within the coverage area of ​​the terminal device and is providing normal service. In this process, the terminal device does not perform initial cell selection to avoid searching for cells of NTN devices that are not indicated by the network.

[0191] For example, the terminal device may perform cell selection based on stored information to perform cell search whenever it is determined, based on the acquired device information of the NTN device, that any of the at least one NTN device has reached the coverage area of ​​the terminal device and is providing normal service; if a second cell is found, the terminal device may camp on the second cell.

[0192] The second cell is the serving cell of the third NTN device, which can be any of the NTN devices that have obtained the device information.

[0193] As an example, a terminal device can determine, based on the acquired trajectory information of an NTN device and the location information of the terminal device, that an NTN device has arrived or is about to arrive within the coverage area of ​​the terminal device, and if it is determined that the NTN device can provide normal service based on the service time of the NTN device, then it can perform cell search based on the frequency information of the NTN device. That is, it can attempt to search for the serving cell of the NTN device by scanning the frequency of the NTN device, and if the serving cell of the NTN device is found, it can camp on the serving cell to establish an initial communication connection with the serving cell.

[0194] S404, The terminal equipment resides in the service cell of the third NTN equipment.

[0195] After residing in the serving cell of the third NTN device, the terminal device can establish a connection with the third NTN device and, upon successful connection establishment, receive downlink information and transmit uplink information. The uplink information includes uplink signaling and / or uplink data, and the downlink information includes downlink signaling and / or downlink data.

[0196] For example, a terminal device can initiate a random access request to a third NTN device and establish uplink synchronization with the third NTN device to successfully access the serving cell of the third NTN device. After successfully accessing the serving cell of the third NTN device, the terminal device can receive downlink information sent by the third NTN device and can also send uplink information to the third NTN device.

[0197] In one embodiment, when the terminal device is camped in the first cell, after sending uplink information to the first NTN device, the first NTN device can forward the uplink information of the terminal device to the terrestrial network. The terrestrial network processes the uplink information of the terminal device to generate downlink information of the terminal device and sends the downlink information of the terminal device to the third NTN device. After the terminal device camps in and accesses the serving cell of the third NTN device, the third NTN device will forward the downlink information of the terminal device to the terminal device.

[0198] In one embodiment, after the terrestrial network generates downlink information for the terminal device based on the uplink information of the terminal device, it can determine the third NTN device that will serve the terminal device based on information such as the load and trajectory of the NTN device, and send the downlink information of the terminal device to the third NTN device.

[0199] In this embodiment, the terminal device receives an NTN device list from the currently residing NTN device. Based on the device information of at least one NTN device included in the NTN device list, it performs cell selection based on stored information. This allows the terminal device to perform cell search and cell selection within the serving cell of the at least one NTN device, thereby improving the efficiency of cell search and selection and reducing device power consumption. Furthermore, this cell selection method ensures that the terminal device searches within the serving cell of the NTN device indicated by the network, avoiding searches within the serving cell of an NTN device not indicated by the network. This prevents problems such as the need to re-initiate the registration process due to searching within the serving cell of an NTN device not indicated by the network, thus improving the continuity and stability of network communication.

[0200] The following section uses satellite communication as an example to describe in detail the cell selection method provided in the embodiments of this application, with reference to the accompanying drawings.

[0201] Figure 5 is a schematic flowchart of a cell selection method in a satellite communication system provided in an embodiment of this application. As shown in Figure 5, the satellite communication system includes a UE, satellites, and a terrestrial network. The satellites include at least Satellite 1 and Satellite 2. In this embodiment, an access network device and a core network device are deployed on Satellite 1 as an example. It should be understood that the core network device may not be deployed on Satellite 1 (e.g., deployed in the terrestrial network), or only some of its functions may be deployed on Satellite 1 (e.g., some functions are deployed on Satellite 1, and other functions are deployed in the terrestrial network). The method includes the following steps:

[0202] S501. When selecting a new mobile network, the UE performs initial cell selection to conduct cell search.

[0203] When a UE needs to select a new Public Land Mobile Network (PLMN) or Stand-Alone Non-Public Network (SNPN), it needs to perform cell selection and perform initial cell selection without stored information.

[0204] For example, a UE may need to select a new PLMN or SNPN when powering on for the first time or when switching mobile networks, and perform initial cell selection without storing information.

[0205] This stored information is used to store key information to assist the UE in cell selection, such as the frequency points of previously camped cells. Without this stored information, the UE needs to perform initial cell selection. During this process, the UE needs to scan all supported frequency bands and points to search for available cells. For each cell found, the UE needs to measure its signal quality and then select a suitable cell to camp on based on the signal quality measurement results.

[0206] It should be noted that the embodiments in this application only take the initial cell selection performed by the UE when selecting a new mobile network as an example. It should be understood that when the UE selects a new mobile network, if there is already stored information, it can also perform cell selection based on the stored information. The stored information may include information such as the frequency points of previously camped cells, or it may be satellite information of satellites in the received satellite ID list. The embodiments in this application do not limit this.

[0207] S502, the UE is searching for and camping on cell 1, which is the serving cell of satellite 1.

[0208] After the UE is camped on cell 1, it can also initiate a random access request to satellite 1 to access cell 1. For example, satellite 1 can send a random access request to the core network equipment through the access network equipment to access cell 1.

[0209] After successfully accessing cell 1, the UE can receive downlink signaling and data, as well as send uplink signaling and data. For example, the UE can receive downlink signaling / data forwarded by satellite 1, and send uplink signaling / data to satellite 1.

[0210] S503, the access network equipment on satellite 1 forwards downlink signaling / data to the UE.

[0211] S504, the UE sends uplink signaling / data to the access network equipment on satellite 1.

[0212] After receiving the uplink signaling / data sent by the UE, Satellite 1 can store or forward the uplink signaling / data of the UE. For example, it can forward the uplink signaling / data of the UE to the terrestrial network.

[0213] S505, the core network equipment on satellite 1 sends NAS signaling to the UE through the access network equipment on satellite 1. The NAS signaling carries a satellite ID list, which includes the satellite IDs of at least one satellite.

[0214] During the process of the core network equipment sending NAS signaling to the UE through the access network equipment, the core network equipment can send the NAS signaling to the access network equipment, which then transparently transmits the NAS signaling to the terminal equipment. That is, in this process, the access network equipment only performs the transparent transmission operation of the NAS signaling and is unaware of the satellite ID list carried in the NAS signaling.

[0215] The core network equipment on satellite 1 can send NAS signaling carrying the satellite ID list to the UE when its location, coverage area, or service status changes, such as when it is about to leave the UE's coverage area or is unable to continue providing services to the UE.

[0216] The satellite ID list may include the satellite IDs of the satellites that the UE should connect to to continue performing store-and-forward operations of signaling and user plane data, so as to inform the UE via NAS signaling which satellites it can continue to perform store-and-forward operations of signaling and user plane data.

[0217] For example, the satellite ID list may include satellite id-r17, satellite id-v1800, and satellite id-v1830.

[0218] As an example, the core network device can send a connection release notification to the UE via the access network device when satellite 1 is about to leave the UE's coverage area. This connection release notification carries a satellite ID list. Alternatively, the core network device can send a registration rejection message to the UE via the access network device, which also carries a satellite ID list. It should be understood that satellite 1 can also send a satellite ID list to the UE via other NAS signaling, and this application embodiment does not limit this.

[0219] S506. The UE determines the satellite information of the first part of the satellite in the satellite ID list from the received SIB32 information.

[0220] When a UE is camped in cell 1, it can also receive SIB32 information broadcast by the access network equipment on satellite 1. The access network equipment on satellite 1 typically broadcasts SIB32 information when it needs to provide UEs within its coverage area with satellite auxiliary information that predicts discontinuous coverage, such as when satellite 1 enters a new coverage area or when satellite auxiliary information needs to be updated.

[0221] The SIB32 information may include satellite auxiliary information, such as satellite information of one or more satellites. The satellite information includes at least the service time, frequency, and ephemeris of the corresponding satellite, and may also include other satellite information such as coverage information; however, this embodiment does not limit this.

[0222] After receiving the satellite ID list, the UE can first match the NTN device list with the received SIB32 information to determine whether satellite information for each satellite in the satellite ID list exists in the SIB32 information. If satellite information for some satellites in the satellite ID list exists in the SIB32 information, then the satellite information for these satellites is retrieved from the SIB32 information. For ease of explanation, this part of the satellites is referred to as the first part of the satellites, and the satellites in the satellite ID list other than the first part of the satellites are referred to as the second part of the satellites.

[0223] It should be noted that if the UE was previously camped on a serving cell of another satellite before camping on cell 1, the UE can also receive SIB32 information broadcast by that other satellite. In other words, the SIB32 information received by the UE can include SIB32 information broadcast by satellite 1, as well as SIB32 information broadcast by other satellites.

[0224] S507, the UE sends a satellite information request 1 to the access network equipment on satellite 1. The satellite information request 1 carries the satellite IDs of the satellites in the second part of the satellite ID list. The second part of the satellites refers to the satellites in the satellite ID list other than the satellites in the first part.

[0225] If the SIB32 information received by the UE contains only satellite information for some of the satellites in the satellite ID list, the UE can also send a satellite information request to the access network equipment on satellite 1 to obtain satellite information for all or some of the remaining satellites in the satellite ID list.

[0226] For example, suppose the satellite ID list includes satellite ID-r17, satellite ID-v1800, and satellite ID-v1830; the SIB32 information received by the UE includes satellite information for satellite ID-r17 but excludes satellite information for satellite ID-v1800 and satellite ID-v1830. The UE can then obtain the satellite information for satellite ID-r17 from the received SIB32 information and send Satellite Information Request 1 to the access network device on satellite 1. Satellite Information Request 1 carries satellite ID-v1800 and satellite ID-v1830 to obtain their satellite information from satellite 1. Thus, by combining the received SIB32 information and the satellite information request, the UE can obtain satellite information for all satellites in the satellite ID list.

[0227] As an example, the UE can send an RRC reconfiguration request message to the access network device on satellite 1, which carries the satellite information request. For example, the RRC reconfiguration request message includes the requested SIB type and the satellite ID of the second part of the satellites, requesting the access network device on satellite 1 to return the satellite information of the second part of the satellites through the SIB information corresponding to the SIB type. The SIB type includes at least SIB32.

[0228] S508, the access network equipment on satellite 1 sends satellite information of the satellite in the second part of the satellite to the UE according to satellite information request 1.

[0229] For example, satellite 1 can send SIB32 information to the UE according to satellite information request 1. The SIB32 information carries all or part of the satellite information of the second part of the satellite.

[0230] After receiving the satellite information request 1 from the UE, the access network device on satellite 1 can first obtain the corresponding satellite information based on the satellite ID of the satellite in the second part of the satellite information request 1, and then send the obtained satellite information to the UE.

[0231] In one embodiment, after receiving the satellite information request 1 from the UE, the access network device can obtain the satellite information of the satellites in the second part of the satellites based on its own stored satellite information, or it can obtain the satellite information of the satellites in the second part of the satellites based on its own stored satellite information and the core network satellites. For example, it can obtain the satellite information of the satellites in the second part of the satellites based on the stored satellite information and the satellite information request sent to the core network device.

[0232] For example, if Satellite Information Request 1 carries the satellite IDs of all satellites in the second part of the satellites, the access network device can obtain the satellite information of all satellites in the second part of the satellites from the stored satellite information, provided that the stored satellite information includes the satellite information of all satellites in the second part of the satellites.

[0233] Alternatively, if the stored satellite information includes satellite information for some satellites in the second part of the satellites, the satellite information for those satellites is retrieved from the stored satellite information, and a satellite information request 2 is sent to the core network equipment. Satellite information request 2 carries the satellite IDs of the remaining satellites in the second part of the satellites. Then, the satellite information for the remaining satellites sent by the core network equipment is received.

[0234] Alternatively, if the stored satellite information does not include satellite information for any of the satellites in the second part of the satellites, a satellite information request 2 is sent to the core network equipment, carrying the satellite IDs of all or some of the satellites in the second part of the satellites. Then, the satellite information for the satellites in the second part of the satellites is received from the core network equipment.

[0235] It should be noted that the embodiments in this application only use the example of satellite information of some satellites in the satellite ID list in the SIB32 information received by the UE. It should be understood that when the SIB32 information received by the UE contains satellite information of all satellites in the satellite ID list, the UE does not need to send a satellite information request to the access network device on satellite 1; or, when the SIB32 information received by the UE does not contain satellite information of any satellite in the satellite ID list, the UE can still send a satellite information request carrying the satellite IDs of the satellites in the satellite ID list to the access network device on satellite 1 to obtain the satellite information of the satellites in the satellite ID list.

[0236] S509, the UE adds the satellite channel information from the obtained satellite ID list to the UE's stored information.

[0237] By adding the channel information of the satellites in the obtained satellite ID list to the UE's stored information, the UE can perform cell search based on the frequency information of the satellites in the satellite ID list when performing cell selection based on stored information. This can speed up cell search efficiency and help the UE quickly find and camp on a suitable cell.

[0238] In addition, the UE can also add other satellite information such as service time or ephemeris of satellites in the satellite ID list to the UE's stored information, but this application embodiment does not limit this.

[0239] In addition, after receiving uplink signaling / data from the UE, satellite 1 can forward the UE's uplink signaling / data to the ground network. The ground network then processes the UE's uplink signaling / data to generate the UE's downlink signaling / data. During the generation of the UE's uplink signaling / data, the ground network can also determine the next satellite 2 to serve the UE based on information such as satellite load and ephemeris data in the NTN network, and forward the UE's downlink signaling / data to satellite 2.

[0240] The S510 and Satellite 1 access network equipment forward the UE's uplink signaling / data to the terrestrial network.

[0241] S511. After processing the uplink signaling / data of the UE, the terrestrial network sends the downlink signaling / data of the UE to satellite 2.

[0242] After storing the satellite information of each satellite in the satellite ID list in the storage information, the UE can decide whether to hibernate or start cell search based on the stored information, and decide when to hibernate and when to start cell search. In this way, cell search can be started at the appropriate time, thereby saving power consumption.

[0243] S512. When the UE determines, based on the acquired satellite information, that any satellite in the satellite ID list has reached the UE's coverage area and is providing normal service, it performs cell selection based on stored information to conduct cell search.

[0244] In other words, the UE can initiate network search by performing cell selection based on stored information when it determines that any satellite in the satellite ID list has reached its coverage area and is providing normal service, based on the satellite information obtained from the satellite ID list. Furthermore, the UE does not perform initial cell selection during this stage to avoid searching for and residing in satellite cells not indicated by the network.

[0245] For example, based on the satellite trajectory information in the obtained satellite ID list and the UE's own location information, the UE can determine that a certain satellite (satellite 2) has arrived or is about to arrive in the coverage area of ​​the terminal device. If the UE determines that satellite 2 can provide normal service based on the service time of satellite 2, it can perform cell search based on the frequency information of satellite 2. That is, it can try to search for the serving cell of satellite 2 by scanning the frequency of satellite 2. If the serving cell of satellite 2 is found, it can camp on that serving cell to establish a preliminary communication connection with that serving cell.

[0246] S513. When the UE finds cell 2, it camps on and accesses satellite 2. Cell 2 is the serving cell of satellite 2.

[0247] After camping on cell 2, the UE can initiate a random access request to satellite 2 to access cell 2. Upon successful access to cell 2, the UE can receive downlink signaling and data, as well as send uplink signaling and data. For example, the UE can receive downlink signaling / data forwarded by satellite 2, and send uplink signaling / data to satellite 2.

[0248] S514. Satellite 2 forwards the UE's downlink signaling / data to the UE.

[0249] S515, UE sends uplink signaling / data to satellite 2.

[0250] The method embodiments provided in this application have been described above. The apparatus embodiments provided in this application will be described below. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments. Therefore, any content not described in detail can be referred to the method embodiments above. For the sake of brevity, it will not be repeated here.

[0251] Figure 6 is a schematic block diagram of a communication device provided in an embodiment of this application. As shown in Figure 6, the communication device 600 may include a communication unit 610 and a processing unit 620. The communication unit 610 can implement corresponding communication functions, which can be internal communication within the communication device 600 or communication between the communication device 600 and other devices; the processing unit 620 can implement corresponding processing functions. The communication unit 610 may also be referred to as a communication interface or a transceiver unit. Optionally, the communication device 600 may further include a storage unit, which can be used to store instructions and / or data, and the processing unit 620 can read the instructions and / or data in the storage unit to enable the device to implement the aforementioned method embodiment.

[0252] It should be understood that the communication device 600 may be a terminal device, or a module or chip that performs the functions of a terminal device.

[0253] The communication unit 610 can be used to receive an NTN device list sent by a first NTN device when camped in a first cell, wherein the first cell is the serving cell of the first NTN device, and the NTN device list includes the device identifier of at least one NTN device in the NTN network.

[0254] The processing unit 620 can be used to perform cell selection based on stored information based on the device information of the at least one NTN device, so as to select a cell for camping from the serving cells of the at least one NTN device. The device information includes the service time, frequency information and trajectory information of the corresponding NTN device.

[0255] It should be understood that the communication device 600 can be an NTN device, or a module or chip that performs the functions of an NTN device. The NTN device mentioned here can be, for example, a satellite or high-altitude platform, or a network element, module, or chip deployed on a satellite or high-altitude platform.

[0256] The communication unit 610 can be used to send an NTN device list to a terminal device residing in the first NTN device. The NTN device list includes the device identifier of at least one NTN device in the NTN network, so that the terminal device can perform cell selection based on stored information based on the device information of each of the at least one NTN device, so as to select a cell to camp on from the serving cells of the at least one NTN device.

[0257] The communication unit 610 can also be used to receive a device information request sent by the terminal device, the device information request carrying the device identifiers of all or some of the at least one NTN device; and send the device information of all or some of the devices to the terminal device.

[0258] It should be understood that the communication device 600 can be a core network device, or a module or chip that performs the functions of the core network device. Optionally, all or part of the functions of the core network device can be deployed on the NTN device.

[0259] The communication unit 610 can be used to send an NTN device list to a terminal device residing in the serving cell of a first non-terrestrial network NTN device. The NTN device list includes the device identifier of at least one NTN device in the NTN network, so that the terminal device can perform cell selection based on stored information based on the device information of the at least one NTN device. The device information refers to the device information required to perform cell selection based on stored information.

[0260] The communication unit 610 can also be used to receive a second device information request sent by the access network device, the second device information request carrying the device identifier of a second target NTN device, the second target NTN device including all or some of the at least one NTN device; and send the device identifier of the NTN device in the second target NTN device to the access network device.

[0261] It should be understood that the communication device 600 can be an access network device, or a module or chip that performs the functions of an access network device. The access network device is deployed on the first NTN device.

[0262] The communication unit 610 can be used to send an NTN device list to a terminal device residing in the serving cell of the first NTN device, the NTN device list including the device identifier of at least one NTN device in the NTN network; receive a first device information request sent by the terminal device, the first device information request carrying the device identifier of a first target NTN device, the first target NTN device including all or part of the devices of the at least one NTN device; and send the device information of the NTN devices in the first target NTN device to the terminal device.

[0263] For details regarding the steps or processes executed by each unit in the communication device 600, please refer to the descriptions in the corresponding methods; they will not be elaborated here.

[0264] It should be understood that the "unit" in the communication device 600 can be implemented in hardware, software, or by hardware executing corresponding software. For example, the "unit" can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, combined logic circuitry, and / or other suitable components supporting the described functions. As another example, the communication unit 610 can be replaced by a transceiver circuit (e.g., it may include receiving and transmitting circuitry), and the processing unit 620 can be replaced by a processor or processing circuitry.

[0265] Figure 7 is a schematic block diagram of another communication device provided in an embodiment of this application. The communication device 700 can be a terminal device / NTN device, or a chip, chip system, or processor in the terminal device / NTN device that implements the above-described method. This device 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.

[0266] The communication device 700 may include one or more processors 710, which may also be referred to as processing units, and can implement certain control functions. The processor 710 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, execute software programs, and process data from the software programs.

[0267] In an alternative design, the processor 710 may also store instructions and / or data that can be executed by the processor 710 to cause the communication device 700 to perform the methods described in the above method embodiments.

[0268] In another alternative design, the communication device 700 may include a communication interface 720 for implementing receiving and transmitting functions. For example, the communication interface 720 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.

[0269] Optionally, the communication device 700 may include one or more memories 730, which may store instructions that can be executed on the processor 710, causing the communication device 700 to perform the methods described in the above method embodiments. Optionally, the memories 730 may also store data. Optionally, the processor 710 may also store instructions and / or data. The processor 710 and the memories 730 may be provided separately or integrated together.

[0270] 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 method 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.

[0271] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuitry in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located 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 the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0272] 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 link 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.

[0273] This application also provides a computer program product, which includes computer program code. When the computer program code is run on a computer, it causes the computer to execute the various steps or processes executed by the terminal device / network device in any of the above method embodiments.

[0274] This application also provides a computer-readable storage medium storing program code that, when run on a computer, causes the computer to execute the various steps or processes performed by the terminal device / network device in any of the above method embodiments.

[0275] This application also provides a communication device, including a processor and an interface, the interface being used to send and / or receive signals, causing the processor to execute the various steps or processes executed by the terminal device / network device in any of the above method embodiments.

[0276] The above-described device and method embodiments are completely corresponding, with corresponding modules or units performing corresponding steps. For example, a communication unit or communication interface performs the receiving or sending steps in the method embodiment, while other steps besides sending and receiving can be performed by a processing unit or processor.

[0277] 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. The embodiments of this application do not preclude the possibility of defining other terms that can achieve the same or similar functions in existing or future agreements.

[0278] As used in this specification, the terms "component," "module," "system," etc., are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process and / or an execution thread, and components may be located on a single computer and / or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable storage media on which various data structures are stored. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0279] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0280] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be based on the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0281] 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.

[0282] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0283] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0284] In the above embodiments, the functions of each functional unit can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0285] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially or in other words, the parts that contribute to the prior art, or parts of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0286] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for selecting a cell, characterized in that, When applied in a terminal device, the method includes: When camped in the first cell, the NTN device list sent by the first non-terrestrial network NTN device is received, where the first cell is the serving cell of the first NTN device, and the NTN device list includes the device identifier of at least one NTN device in the NTN network. Based on the device information of the at least one NTN device, cell selection based on stored information is performed to select a cell from the serving cells of the at least one NTN device for camping, wherein the device information refers to the device information required to perform cell selection based on stored information.

2. The method as described in claim 1, characterized in that, Before performing cell selection based on stored information based on the device information of the at least one NTN device, the method further includes: Based on the received system information and / or the first device information request sent to the first NTN device, determine the device information of all or part of the NTN devices in the at least one NTN device; The system information includes first system information broadcast by the first NTN device, and the first device information request carries the device identifier of the first target NTN device for requesting the device information of the first target NTN device. The first target NTN device includes all or part of the at least one NTN device.

3. The method as described in claim 2, characterized in that, The step of determining the device information of all or part of the at least one NTN devices based on received system information and / or a first device information request sent to the first NTN device includes: If the system information contains device information for all devices in the at least one NTN device, then the device information for all devices in the at least one NTN device is obtained from the system information. If the system information contains device information for some of the at least one NTN devices, then the device information for the first part of the devices is obtained from the system information. The first part of the devices refers to the NTN devices whose corresponding device information exists in the system information. A first device information request is sent to the first NTN device, the first device information request carrying the device identifier of the NTN devices in the second part of the devices. The second part of the devices refers to the NTN devices other than the first part of the devices in the at least one NTN device. The device information of the NTN devices in the second part of the devices is received from the first NTN device. If the system information does not contain device information for any of the at least one NTN devices, then a first device information request is sent to the first NTN device, the first device information request carrying the device identifier of the at least one NTN device; and the device information of the at least one NTN device sent by the first NTN device is received.

4. The method as described in claim 3, characterized in that, The system information also includes first system information broadcast by at least one second NTN device, wherein the at least one second NTN device refers to the NTN device corresponding to the NTN cell in which the terminal device camped before camping on the first cell.

5. The method as described in claim 3 or 4, characterized in that, Sending the first device information request to the first NTN device includes: Send a Radio Resource Control (RRC) reconfiguration request message to the first NTN device, the RRC reconfiguration request message carrying the first device information request; The step of receiving the device information of the NTN devices in the second part of the device sent by the first NTN device includes: Receive second system information sent by the first NTN device, wherein the second system information carries device information of the NTN device in the second part of the device; The step of receiving device information of the at least one NTN device from the first NTN device includes: The system receives second system information sent by the first NTN device, the second system information carrying device information of the NTN device among the at least one NTN device.

6. The method as described in claim 5, characterized in that, The first device information request includes the system information block (SIB) type to be obtained and the device identifiers of all or some of the devices in the at least one NTN device. The second system information is SIB information corresponding to the SIB type, and the SIB type includes at least SIB32.

7. The method according to any one of claims 2-6, characterized in that, The first system information is SIB information, and the SIB information includes at least SIB32 information.

8. The method according to any one of claims 1-7, characterized in that, The device information includes the service time, frequency information, and trajectory information of the corresponding NTN device.

9. The method according to any one of claims 1-8, characterized in that, The device information includes frequency point information corresponding to the NTN device, and the method further includes: The frequency point information of the NTN device in the at least one NTN device is stored in the auxiliary information set of the terminal device, and the auxiliary information set includes information obtained from a database or stored information.

10. The method according to any one of claims 1-9, characterized in that, The step of performing cell selection based on stored information based on the device information of the at least one NTN device includes: Whenever it is determined, based on the device information of the at least one NTN device, that any one of the at least one NTN devices has reached the coverage area of ​​the terminal device and is providing normal service, cell selection based on stored information is performed to conduct cell search; If a second cell is found, the device camps on the second cell, which is the serving cell of the third NTN device, which is any one of the at least one NTN device.

11. The method as described in claim 10, characterized in that, If a second cell is found, after camping on the second cell, the method further includes: Establish a connection with the third NTN device; After successfully establishing a connection with the third NTN device, the system receives downlink information sent by the third NTN device, the downlink information including downlink signaling and / or downlink data; Uplink information is sent to the third NTN device, the uplink information including uplink signaling and / or uplink data.

12. The method according to any one of claims 1-11, characterized in that, The NTN device list received from the first NTN device includes: Receive non-access stratum NAS signaling sent by the first NTN device, wherein the NAS signaling carries the list of NTN devices.

13. The method as described in claim 12, characterized in that, The receiving of NAS signaling sent by the first NTN device includes: After sending a registration request to the first NTN device, a registration rejection message is received from the first NTN device, the registration rejection message carrying the NTN device list; or, Receive a connection release notification sent by the first NTN device, the connection release notification carrying the list of NTN devices.

14. A communication method, characterized in that, Applied to core network equipment, the method includes: An NTN device list is sent to a terminal device residing in the serving cell of a first non-terrestrial network NTN device. The NTN device list includes the device identifier of at least one NTN device in the NTN network, so that the terminal device can perform cell selection based on stored information based on the device information of the NTN device among the at least one NTN device. The device information refers to the device information required to perform cell selection based on stored information.

15. The method as described in claim 14, characterized in that, Sending the NTN device list to the terminal devices residing in the first NTN device includes: Send a non-access stratum (NAS) signaling message to the terminal device, the NAS signaling message carrying the NTN device list.

16. The method as described in claim 15, characterized in that, The method further includes: The device receives a second device information request sent by an access network device. The second device information request carries the device identifier of a second target NTN device. The second target NTN device includes all or some of the devices in the at least one NTN device. Send the device identifier of the NTN device in the second target NTN device to the access network device.

17. A communication method, characterized in that, Applied to an access network device deployed on a first non-terrestrial network (NTN) device, the method includes: Send an NTN device list to terminal devices residing in the serving cell of the first NTN device, the NTN device list including the device identifier of at least one NTN device in the NTN network; The terminal device receives a first device information request, the first device information request carrying the device identifier of a first target NTN device, the first target NTN device including all or part of the at least one NTN device; Send the device information of the NTN device in the first target NTN device to the terminal device.

18. The method as described in claim 17, characterized in that, The receiving of the first device information request sent by the terminal device includes: The terminal device receives a Radio Resource Control (RRC) reconfiguration request message, the RRC reconfiguration request message carrying the first device information request. Sending the device information of the first target NTN device to the terminal device includes: Send second system information to the terminal device, the second system information carrying device information of the NTN device in the first target NTN device.

19. The method as described in claim 18, characterized in that, The first device information request includes the system information block (SIB) type to be obtained and the device identifier of the first target NTN device. The second system information is SIB information corresponding to the SIB type, and the SIB type includes at least SIB32.

20. The method according to any one of claims 17-19, characterized in that, After receiving the first device information request sent by the terminal device, the method further includes: Based on the stored device information and / or the second device information request sent to the core network device, obtain the device information of the NTN devices in the first target NTN device; wherein, the second device information request carries the device information of all or part of the devices in the first target NTN device.

21. The method as described in claim 20, characterized in that, The step of obtaining the device information of the NTN device in the first target NTN device based on the stored device information and / or the second device information request sent to the core network device includes: If the stored device information includes the device information of all devices in the first target NTN device, then the device information of all devices in the first target NTN device is obtained from the stored device information. If the stored device information includes device information of some devices in the first target NTN device, the device information of the partial devices is obtained from the stored device information; a second device information request is sent to the core network device, the second device information request carrying the device identifier of the NTN device in the remaining part of the first target NTN device; and the device information of the NTN device in the remaining part of the device is received from the core network device. If the stored device information does not include the device information of any of the first target NTN devices, a second device information request is sent to the core network device, the second device information request carrying the device identifier of the NTN device in the first target NTN device; and the device information of the NTN device in the first target NTN device sent by the core network device is received.

22. The method according to any one of claims 17-21, characterized in that, The method further includes: Broadcast information from the first system.

23. The method as described in claim 22, characterized in that, The first system information is SIB information, and the SIB information includes at least SIB32 information.

24. A communication device, characterized in that, The communication device includes: one or more processors, and a memory; the memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, and the one or more processors invoking the computer instructions to cause the communication device to perform the method as described in any one of claims 1-13, or claims 14-16, or claims 17-23.

25. A network system, characterized in that, The network system includes a first communication device, a second communication device, and a third communication device. The first communication device is used to perform the method as described in any one of claims 1-13, the second communication device is used to perform the method as described in any one of claims 14-16, and the third communication device is used to perform the method as described in any one of claims 17-23.

26. A network system, characterized in that, The network system includes a second communication device and a third communication device, the second communication device being used to perform the method as described in any one of claims 14-16, and the third communication device being used to perform the method as described in any one of claims 17-23.

27. A chip system, characterized in that, The chip system is applied to an electronic device, the chip system including one or more processors, the one or more processors being configured to invoke computer instructions to cause the electronic device to perform the method as described in any one of claims 1-13, or claims 14-16, or claims 17-23.

28. A computer program product, characterized in that, The computer program product includes computer program code that, when run on an electronic device, causes the electronic device to perform the method as described in any one of claims 1-13, 14-16, or 17-23.

29. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes instructions that, when executed on an electronic device, cause the electronic device to perform the method as described in any one of claims 1-13, 14-16, or 17-23.

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