Communication method and related apparatus

Abstract

A communication method and a related apparatus, which are beneficial to reducing signaling overhead of indicating common TAs of non-serving satellites. The method comprises: a serving satellite generates first indication information, the first indication information being used for indicating: a difference between a common TA of the serving satellite and a common TA of a non-serving satellite or a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite; the serving satellite sends the first indication information to a terminal; and the terminal determines the common TA of the non-serving satellite on the basis of the first indication information and the common TA of the serving satellite.

Description

Communication method and related apparatus

[0001] This application claims priority from the Chinese patent application No. 202410481113.1 filed on April 19, 2024, and entitled "Communication method and related apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

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

[0003] Non-terrestrial networks (NTN) communication has the characteristics of large coverage area and flexible networking, and can achieve seamless global network coverage. NTN network is not only a supplement to the current ground network, but also can be regarded as an independent communication system that provides global high-speed network access for users. NTN communication includes networking by using unmanned aerial vehicles, high-altitude platforms, satellites and other devices to provide data transmission, voice communication and other services for terminals.

[0004] In the NTN scenario, in order to provide better network services for the terminal, the network side can support the terminal to access the service satellite and the non-service satellite at the same time, and the service satellite and the non-service satellite can cooperate to provide network services for the terminal. Among them, the terminal needs to access the non-service cell based on the common timing advance (TA) of the non-service satellite.

[0005] However, the current way of indicating the common TA of the non-service satellite will bring too much signaling overhead. SUMMARY

[0006] The present application provides a communication method and related apparatus, which is beneficial to reduce the signaling overhead of indicating the common TA of the non-service satellite.

[0007] In a first aspect, a communication method is provided, which can be executed by a first communication apparatus. The first communication apparatus can be a terminal, a component (such as a processor, circuit or chip, or a chip system, etc.) configured in the terminal, and can also be a logic module or software capable of realizing all or part of the terminal functions, and the present application does not make any limitation in this regard. In the following, the first communication apparatus is taken as an example of a terminal to introduce the communication method of the present application.

[0008] The method comprises: receiving first indication information from a satellite, the satellite being a serving satellite or a non-serving satellite of the terminal, the first indication information being used to indicate: a difference between a common TA of the serving satellite and a common TA of the non-serving satellite, or a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite; and determining the common TA of the non-serving satellite based on the first indication information and the common TA of the serving satellite.

[0009] Since the terminal has accessed the serving satellite based on the common TA of the serving satellite before receiving the first indication information, in other words, the terminal knows the common TA of the serving satellite. Therefore, the terminal can determine the common TA of the non-serving satellite based on the first indication information and the common TA of the serving satellite after receiving the first indication information. Compared with a manner of directly indicating the common TA of the non-serving satellite, the manner of indirectly indicating the common TA of the non-serving satellite through the difference or the derivative is advantageous in reducing signaling overhead.

[0010] With reference to the first aspect, in some implementations of the first aspect, the derivative comprises: a first-order derivative and / or a second-order derivative.

[0011] With reference to the first aspect, in some implementations of the first aspect, before receiving the first indication information from the satellite, the method further comprises: receiving second indication information from the serving satellite, the second indication information being used to indicate a physical cell identifier (PCI) of the non-serving satellite.

[0012] With reference to the first aspect, in some implementations of the first aspect, the satellite is a non-serving satellite of the terminal; and receiving the first indication information from the satellite comprises: receiving the first indication information from the satellite based on the second indication information.

[0013] With reference to the first aspect, in some implementations of the first aspect, receiving the first indication information from the satellite based on the second indication information comprises: receiving a synchronization signal block (SSB) from the non-serving cell based on the PCI; and receiving the first indication information from the satellite after achieving downlink synchronization based on the SSB.

[0014] With reference to the first aspect, in some implementations of the first aspect, the first indication information is carried in a system information block (SIB).

[0015] In some implementations of the first aspect, before receiving the first indication information from the satellite, the method further includes: sending, to the serving satellite, a request message, the request message being used to request the common TA of the non-serving satellite, or the request message being used to request to indicate the common TA of the non-serving satellite in a target manner, the target manner being to indicate a difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or to indicate a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0016] In the present application, the terminal sends the request message to the serving satellite, which is beneficial for the terminal to understand the content indicated by the first indication information.

[0017] In some implementations of the first aspect, before receiving the first indication information from the satellite, the method further includes: receiving third indication information from the serving satellite, the third indication information being used to indicate that the common TA of the non-serving satellite will be indicated in a target manner, the target manner being to indicate a difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or to indicate a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0018] The third indication information used to indicate that the common TA of the non-serving satellite will be indicated in a target manner can be alternatively described as the third indication information being used to indicate the content indicated by the first indication information, the content indicated by the first indication information being a difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0019] In the present application, the terminal receives the third indication information from the serving satellite, which is beneficial for the terminal to understand the content indicated by the first indication information sent by the serving satellite.

[0020] In some implementations of the first aspect, the third indication information is carried in a physical downlink control channel (PDCCH) order.

[0021] The second aspect provides a communication method, which can be executed by a second communication device. The second communication device can be a serving satellite, or a component (for example, a processor, a circuit, a chip, or a chip system, etc.) configured in the serving satellite, or a logic module or software capable of implementing all or part of the functions of the serving satellite, and the present application does not make any limitation in this regard. Hereinafter, the communication method of the present application will be introduced by taking the second communication device as an example.

[0022] The method comprises: generating first indication information, the first indication information being used to indicate a difference between a common TA of a serving satellite of the terminal and a common TA of a non-serving satellite of the terminal, or a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite; and sending the first indication information to the terminal.

[0023] In the present application, before the serving satellite sends the first indication information to the terminal, the serving satellite has sent the common TA of the serving satellite to the terminal, and the terminal has accessed the serving satellite based on the common TA of the serving satellite. Therefore, in order to reduce the signaling overhead of indicating the common TA of the non-serving satellite, the serving satellite can indirectly indicate the common TA of the non-serving satellite by means of the above-mentioned difference or the above-mentioned derivative. Compared with the way of directly indicating the common TA of the non-serving satellite, this method is advantageous in reducing the signaling overhead of indicating the common TA of the non-serving satellite.

[0024] With reference to the second aspect, in some implementations of the second aspect, the derivative comprises: a first-order derivative and / or a second-order derivative.

[0025] With reference to the second aspect, in some implementations of the second aspect, before the first indication information is sent to the terminal, the method further comprises: sending second indication information to the terminal, the second indication information being used to indicate a PCI of the non-serving satellite.

[0026] With reference to the second aspect, in some implementations of the second aspect, the first indication information is carried in a SIB.

[0027] With reference to the second aspect, in some implementations of the second aspect, before the first indication information is sent to the terminal, the method further comprises: receiving a request message from the terminal, the request message being used to request the common TA of the non-serving satellite, or the request message being used to request to indicate the common TA of the non-serving satellite in a target manner, the target manner being: indicating the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or indicating the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0028] In the present application, the serving satellite receives the request message from the terminal, and then the serving satellite can indicate the common TA of the non-serving satellite in the indication manner requested by the terminal, which is advantageous in helping the terminal to understand the content indicated by the first indication information.

[0029] In some implementations of the second aspect, in combination with the second aspect, before sending the first indication information to the terminal, the method further includes: sending third indication information to the terminal, the third indication information being used to indicate that the common TA of the non-serving satellite is indicated in a target manner, the target manner being: indicating a difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or indicating a derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0030] In the present application, the serving satellite sends the third indication information to the terminal, which is beneficial for the terminal to understand the content indicated by the first indication information.

[0031] In some implementations of the second aspect, the third indication information is carried in a PDCCH order.

[0032] In a third aspect, a communication apparatus is provided, which includes: a module configured to perform the method in any possible implementation manner of the above described aspects.

[0033] In one design, the apparatus can include a module corresponding to each of the above described methods / operations / steps / actions in the first aspect, which can be hardware circuit, software, or a combination of hardware circuit and software.

[0034] In another design, the apparatus is a communication chip, which can include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0035] In another design, the apparatus is a terminal or a serving satellite, which can include a transmitter for sending information or data, and a receiver for receiving information or data.

[0036] In another design, the apparatus is configured to perform the method in any possible implementation manner of the above described aspects, and the apparatus can be configured in a terminal or a serving satellite.

[0037] In a fourth aspect, a communication apparatus is provided, which includes at least one processor configured to invoke and run a computer program from a memory, so that the apparatus performs the method in any possible implementation manner of the above described aspects.

[0038] Optionally, the apparatus further includes a memory configured to store instructions and data. The memory is coupled to the processor, and the processor executes the instructions stored in the memory, so as to implement the method described in the above aspects.

[0039] Optionally, the apparatus further includes a transmitter and a receiver, which can be separate or integrated together, referred to as a transceiver.

[0040] In a fifth aspect, a computer program product is provided, which includes a computer program (also referred to as code or instructions), which, when executed by a computer, causes the computer to perform the method in any possible implementation of any of the preceding aspects.

[0041] In a sixth aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code or instructions), which, when executed by a computer, causes the computer to perform the method in any possible implementation of any of the preceding aspects.

[0042] In a seventh aspect, the present application provides a chip system, which includes at least one processor for supporting the functions involved in any possible implementation of any of the preceding aspects, such as receiving or processing the data involved in the above method, etc.

[0043] In a possible design, the chip system further includes a memory for storing program instructions and data, which is located in or outside the processor.

[0044] Optionally, the chip system can be composed of a chip, or include a chip and other discrete devices. BRIEF DESCRIPTION OF DRAWINGS

[0045] FIG. 1 is a schematic diagram of an architecture of a communication system suitable for embodiments of the present application;

[0046] FIG. 2 is a schematic diagram of an architecture of satellite communication suitable for embodiments of the present application;

[0047] FIG. 3 is a schematic flowchart of a communication method provided by embodiments of the present application;

[0048] FIGS. 4 and 5 are schematic block diagrams of communication apparatuses provided by embodiments of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0050] Before introducing the communication method and related apparatus provided by embodiments of the present application, the following points are explained.

[0051] First, in the embodiments shown below, each term and English abbreviation, such as common timing advance, SSB, PCI, etc., is an exemplary example given for the convenience of description, and should not constitute any limitation on the present application. The present application does not exclude the possibility of defining other terms capable of achieving the same or similar functions in existing or future protocols.

[0052] Second, in the embodiments shown below, the first, second, and various numerical numbers are only for the convenience of description, and do not limit the scope of the embodiments of the present application.

[0053] Third, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described, which means that there can be three relationships, for example, A and / or B, which can mean: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, and c can mean: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0054] Fourth, "sending" and "receiving" in the present application represent the direction of signal transmission. For example, "sending first indication information to the terminal" can be understood as the destination of the first indication information being the terminal, which can include direct transmission over the air interface, or indirect transmission over the air interface by other units or modules. "Receiving first indication information from the service satellite" can be understood as the source of the first indication information being the service satellite, which can include direct reception from the service satellite over the air interface, or indirect reception from the service satellite over the air interface from other units or modules. "Sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface.

[0055] In other words, sending and receiving can be between devices, such as between satellites and terminals; or within a device, such as between components, modules, chips, software modules or hardware modules within a device through a bus, wire or interface.

[0056] The related technologies and concepts involved in the present application are introduced as follows.

[0057] 1. NTN communication

[0058] Compared with terrestrial networks (TN) communication, NTN communication has the characteristics of large coverage area, flexible networking, etc., and can achieve seamless global network coverage. NTN network is not only a supplement to the current terrestrial network, but also can be regarded as an independent communication system that provides global high-speed network access for users. At present, research institutes, communication organizations and communication companies around the world are participating in the research of NTN communication technology and standard formulation, trying to build a unified communication network of sky, space and ground.

[0059] NTN communication includes networking by using unmanned aerial vehicles, high-altitude platforms, satellites and other equipment to provide data transmission, voice communication and other services for terminals. High-altitude platform equipment is generally 8-50 km above the ground. According to the orbital height of the satellite, the satellite communication system can be divided into three types: geostationary earth orbit (GEO) satellite communication system (also known as synchronous orbit satellite system), medium earth orbit (MEO) satellite communication system and low earth orbit (LEO) satellite communication system.

[0060] The orbital height of GEO satellite is 35786 km, and its main advantage is that it can remain relatively stationary on the ground and provide a large coverage area. However, GEO satellite communication also has obvious disadvantages: 1) GEO satellite orbit is far from the earth, and the free space propagation loss is large, which causes the communication link budget to be tight. In order to increase the transmission / reception gain, a larger diameter antenna needs to be provided for the satellite; 2) the communication transmission delay is large, which can reach about 500 ms round-trip delay, and cannot meet the demand of low-latency services; 3) GEO orbit resources are relatively scarce, the launch cost is high, and the coverage cannot be provided for the two polar regions of the earth.

[0061] The orbital height of MEO satellite is in the range of 2000-35786 km, and its advantage is that global coverage can be achieved with relatively fewer satellites. However, the orbital height of MEO satellite is higher than that of LEO, and the communication transmission delay is still larger than that of LEO satellite. Considering the advantages and disadvantages of MEO satellite communication, MEO satellite is mainly used for positioning and navigation.

[0062] The orbital height of LEO satellite is in the range of 300-2000 km. LEO satellite has the advantages of smaller data propagation delay, smaller transmission loss and lower launch cost than MEO and GEO. Therefore, LEO satellite communication has attracted more and more attention in recent years.

[0063] In recent years, some companies have planned to build a huge LEO constellation, including thousands or even tens of thousands of LEO satellites. With the increase of the size of the satellite constellation, there will be more than one satellite in the visible range of the terminal. The improvement of system capacity by single-satellite transmission is limited. In order to effectively improve the capacity of the satellite overlapping coverage area, the satellite system gradually evolves from single-satellite transmission to multi-satellite cooperative transmission. Using multi-satellite cooperative transmission can reduce the requirements for single-satellite transmission capacity, and thus reduce the cost of single-satellite manufacturing. Multi-satellite cooperative transmission is a key technology of future satellite communication systems.

[0064] 2、Coordinated multi-point (CoMP) technology

[0065] In TN communication, multi-base station cooperative technology can significantly improve the rate performance of users at the edge of the cell, and the multi-base station cooperative technology is also called CoMP technology. In CoMP, multiple base stations cooperate with each other to provide services for some terminals. CoMP has multiple implementation methods, including: dynamic point selection (DPS), coordinated scheduling (CS), coordinated beamforming (CBF), joint transmission (JT), etc.

[0066] DPS refers to different base stations using different time resources to provide services for terminals, that is, terminals dynamically select different base stations for communication. CS refers to different base stations using different frequency resources to provide services for terminals at the same time, that is, terminals communicate with different base stations on different subcarriers. In addition, CoMP also supports different base stations providing services for terminals on the same time-frequency resources. In the CBF mode, only the base station of one cell transmits useful signals for the terminal, and the base stations of adjacent cooperative cells adjust the beamforming vectors to reduce the interference to the terminal. In the JT mode, multiple base stations are allowed to transmit useful signals for the terminal, and there are two transmission modes: coherent JT (CJT) and non-coherent JT (NCJT). In the CJT mode, multiple base stations transmit the same useful signal for the terminal, which can improve the system performance, but requires ideal backhaul between base stations, and the system implementation is difficult. In the NCJT mode, multiple base stations transmit different useful signals for the terminal, and the backhaul between base stations can be non-ideal, which reduces the difficulty of system implementation, but has certain performance loss compared with the CJT mode.

[0067] In satellite communications, due to the long distance between satellites, it is difficult to guarantee ideal inter-satellite backhaul, which makes it difficult to implement the CJT mode. Compared with the CJT mode, the NCJT mode relaxes the requirement for ideal inter-satellite backhaul and is easier to implement.

[0068] The CoMP technology is also referred to as multi-transmission reception point (multi-TRP) technology in new radio (NR). According to the transmission mode of the PDCCH, the multi-TRP can be divided into two transmission modes: single-downlink control information (single-DCI) based multi-TRP (referred to as single-DCI multi-TRP) and multi-downlink control information (multi-DCI) based multi-TRP (referred to as multi-DCI multi-TRP). In the single-DCI multi-TRP, only one TRP in the multiple TRPs uses one DCI to schedule the terminal; in the multi-DCI multi-TRP, each TRP independently uses different DCIs to schedule the terminal.

[0069] The multi-DCI multi-TRP further includes intra-cell multi-DCI multi-TRP (referred to as intra-cell multi-DCI multi-TRP) and inter-cell multi-DCI multi-TRP (referred to as inter-cell multi-DCI multi-TRP). The intra-cell multi-DCI multi-TRP is for a scenario in which there are multiple TRPs in the same cell, and the inter-cell multi-DCI multi-TRP is for a scenario in which there are multiple TRPs in multiple cells. The single-DCI multi-TRP only supports ideal backhaul between TRPs, and the multi-DCI multi-TRP can support either ideal backhaul or non-ideal backhaul between TRPs. In satellite communications, due to the long distance between satellites, it is difficult to guarantee ideal inter-satellite backhaul.

[0070] To simplify the discussion, the present application considers the scenario that multiple satellites in inter-cell multi-DCI multi-TRP cooperate to provide NCJT for a terminal, in which the terminal can access a serving satellite and a non-serving satellite at the same time.

[0071] In NTN communication, the terminal calculates the TA for accessing the satellite based on the following formula, denoted as T TA : T TA = (N TA +N TA,offset ) × T c + (T TA,common + T TA,UE-specific )

[0072] Where N TA is a closed-loop dynamic value in NR NTN, which is indicated by the base station to the terminal in the TA command of message 2 / message B in the random access channel (RACH), with a length of 12 bits. Alternatively, in the radio resource control (RRC) connected state, it is indicated by the base station to the terminal through the TA command of the media access control (MAC) control element (CE).

[0073] N TA,offset is a closed-loop fixed value in NR NTN, which depends on whether the frequency range is frequency range 1 (FR 1) or frequency range 2 (FR 2), whether it is in the NR and long term evolution (LTE) coexistence scenario, and whether the duplexing mode is time division duplexing (TDD) or frequency division duplexing (FDD).

[0074] T TA,common is an open-loop dynamic value in NR NTN, which is indicated by the base station to the terminal, and is equal to the round-trip delay of the satellite to the reference point (RP). T TA,common includes the common TA at a certain time, the common TA drift rate, and the common TA drift rate variation.

[0075] T TA,UE-specific For the open-loop dynamic value in the NR NTN, it is calculated by the terminal itself according to the ephemeris and its own position, and is equal to the round-trip delay of the satellite to the terminal.

[0076] As shown in the above formula, the base station needs to dynamically indicate T TA,common , T TA,common includes the common TA, the offset rate of the common TA, and the change amount of the offset rate of the common TA, and indicating these three parameters will cause excessive signaling overhead.

[0077] Therefore, embodiments of the present application provide a communication method, in which a serving satellite or a non-serving satellite of a terminal can implicitly (or indirectly) indicate the common TA of the non-serving satellite to the terminal. More specifically, the serving satellite or the non-serving satellite can indirectly indicate the common TA of the non-serving satellite by means of the known common TA of the serving satellite through the relationship between the common TA of the serving satellite and the common TA of the non-serving satellite. For example, the common TA of the non-serving satellite is indicated by indicating the difference between the common TA of the serving satellite and the common TA of the non-serving satellite. For another example, the common TA of the non-serving satellite is indicated by indicating the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0078] FIG. 1 is a schematic diagram of an architecture of a communication system 100 applicable to embodiments of the present application. As shown in FIG. 1, the communication system 100 can include at least one node in a radio access network (RAN), referred to as a RAN node (such as 110a, 110b, 110c in FIG. 1), and can also include at least one terminal (such as 120a-120g in FIG. 1). The RAN nodes and the RAN nodes can be connected to each other by wire or wirelessly. FIG. 1 is only a schematic diagram, and the communication system can also include other network devices, for example, it can also include wireless relay devices and wireless backhaul devices, etc.

[0079] In some scenarios, the roles of the RAN nodes and the terminals are relative, for example, the network element 120c in FIG. 1 can be a helicopter or a drone, which can be configured as a mobile base station. For the terminal 120d that accesses the RAN through the network element 120c, the network element 120c is a base station; but for the base station 110a, the network element 120c is a terminal. The RAN nodes and the terminals are sometimes collectively referred to as communication devices, for example, the network elements 110a, 110b, 110c in FIG. 5 can be understood as communication devices with base station functions, and the network elements 120a-120g can be understood as communication devices with terminal functions.

[0080] In one possible scenario, the RAN node can be a base station, an evolved Node B (eNodeB), an access point (AP), a transmission reception point (TRP), a next generation NodeB (gNB), or a base station in the 5th generation mobile communication technology (5G), a base station in the 6th generation mobile communication technology (6G), a base station in a future mobile communication system, etc. The RAN node can be a macro base station (e.g., 110a in FIG. 1), a micro base station or an indoor station (e.g., 110b in FIG. 1), a relay node or a donor node, or a wireless controller in a cloud radio access network (CRAN) scenario. Optionally, the RAN node can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in the vehicle to everything (V2X) technology can be a road side unit (RSU).

[0081] In another possible scenario, a terminal is assisted by multiple RAN nodes to implement wireless access, and different RAN nodes respectively implement part of the functions of a base station. For example, the RAN node can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a radio frequency remote unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH).

[0082] The CU (or CU-CP and CU-UP), DU or RU can also have different names in different systems, but those skilled in the art can understand their meanings. For example, in an open radio access network (open-RAN, ORAN or O-RAN) system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. Any of the CUs (or CU-CPs, CU-UPs), DUs and RUs in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0083] In combination with the satellite (e.g., 110a in FIG. 1) as a RAN node shown in FIG. 1 described above, FIG. 2 is a schematic diagram of an architecture of satellite communication suitable for embodiments of the present application. FIG. 2 takes the next generation radio access network (NG-RAN) as an example to introduce the communication architecture between a terminal, an NG-RAN, a 5G core network (CN) and a data network (DN) in satellite communication. The satellite in the NG-RAN can be divided into a transparent mode and a regenerative mode according to the working mode. When the satellite works in the transparent mode, the satellite has the function of relay forwarding, and the NTN gateway (gateway) has the function of a base station or part of the base station function, at this time, the NTN gateway can be regarded as a base station. When the satellite works in the regenerative mode, the satellite has data processing capability and has the function of a base station or part of the base station function, at this time, the satellite can be regarded as a base station.

[0084] Referring to FIG. 2, the satellite works in the regenerative mode, the satellite has data processing capability and has the function of a base station or part of the base station function, at this time, the satellite can be regarded as a base station (e.g., gNB in FIG. 2). The service link between the terminal and the satellite exists an NR Uu interface, and the feeder link between the NTN gateway and the satellite is implemented through a satellite radio interface (SRI). The satellites can establish an inter-satellite link (ISL) for communication, and the terminals served by the satellites can access the 5G core network through the ISL. Multiple satellites can cooperate to provide network services for terminals in an overlapping coverage area. Different satellites can be connected to the same 5G core network or different 5G core networks on the ground.

[0085] In addition, the satellite can also serve as an integrated access and backhaul (IAB) node, or as a backhaul part between a base station and a core network, which is not limited in the present application.

[0086] FIG. 3 is a schematic flow chart of a communication method 300 according to an embodiment of the present application. The steps of the method 300 can be performed by interaction between a terminal and a satellite, for example, the 110a shown in FIG. 1 or the gNB shown in FIG. 2, which has the function of a base station or part of the function of a base station.

[0087] The method 300 includes S301-S306, and the specific steps are as follows:

[0088] S301, the satellite generates first indication information, which is used to indicate the difference between the common TA of the serving satellite of the terminal and the common TA of the non-serving satellite of the terminal, or the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0089] In some scenarios, the network side supports the terminal to access the serving satellite and one non-serving satellite at the same time. The serving satellite can configure multiple non-serving cells (referred to as non-serving cells) for the terminal, and each non-serving cell has its corresponding number.

[0090] For example, additional PCIs (additional PCIs) or additional PCI indexes (additional PCI indexes) are used to indicate different non-serving cells.

[0091] For example, the serving satellite configures 7 non-serving cells for the terminal, and uses additional PCI indexes = 1, 2,..., 7 to distinguish 7 different non-serving cells.

[0092] In one possible scenario, if the amount of data to be transmitted by the serving satellite is large, the serving satellite can activate one non-serving satellite for the terminal, and the terminal can access the non-serving satellite based on the common TA of the non-serving satellite. After the terminal accesses the non-serving satellite, the terminal accesses the serving satellite and the non-serving satellite at the same time, and can perform uplink and downlink data transmission with the serving satellite and the non-serving satellite, respectively.

[0093] The satellite in the embodiments of the present application is the serving satellite of the terminal or the non-serving satellite of the terminal, and the non-serving satellite is one of the multiple non-serving satellites of the terminal.

[0094] If the satellite is a serving satellite of the terminal, the serving satellite can obtain the common TA of the non-serving satellite through an inter-satellite link as shown in FIG. 2, further determine the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or determine the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0095] If the satellite is a non-serving satellite of the terminal, the non-serving satellite can obtain the common TA of the serving satellite through an inter-satellite link as shown in FIG. 2, further determine the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or determine the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0096] In one example, the first indication information is the difference between the common TA of the serving satellite and the common TA of the non-serving satellite.

[0097] In another example, the first indication information is the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0098] S302, the satellite sends first indication information to the terminal. Correspondingly, the terminal receives the first indication information.

[0099] For example, the satellite sends the first indication information to the terminal through an NR Uu interface as shown in FIG. 2.

[0100] The satellite can define a signaling format, for example, a format called “TA-Info-differential”, according to which the satellite indicates the difference between the common TA of the serving satellite and the common TA of the non-serving satellite.

[0101] For example, the “TA-Info-differential” format includes the following contents: a “TA-Common-diff” field, used to indicate the difference of the common TA of the non-serving satellite relative to the common TA of the serving satellite at a certain moment; a “TA-CommonDrift-diff” field, used to indicate the difference of the first-order derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite at a certain moment; and a “TA-CommonDriftVariant-diff” field, used to indicate the difference of the second-order derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite at a certain moment.

[0102] The satellite can define a signaling format, for example, a format called “TA-Info-chainrule”, according to which the satellite indicates the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0103] For example, the "TA-Info-chainrule" format includes the following contents: a "TA-Common" field, which is used to indicate the common TA of the non-service satellite at a certain time; a "TA-CommonDrift-chainrule" field, which is used to indicate the first derivative of the common TA of the non-service satellite relative to the common TA of the service satellite; and a "TA-CommonDriftVariant-chainrule" field, which is used to indicate the second derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0104] Optionally, the first indication information is used to indicate the derivative of the common TA of the non-service satellite relative to the common TA of the service satellite, including: the first indication information is used to indicate the first derivative and / or the second derivative of the common TA of the non-service satellite relative to the common TA of the service satellite, so that the common TA of the non-service satellite can be accurately indicated through the first derivative and / or the second derivative on the basis of generating less signaling overhead.

[0105] S303, the terminal determines the common TA of the non-service satellite based on the first indication information and the common TA of the service satellite.

[0106] The terminal has accessed the service satellite based on the common TA of the service satellite before accessing the non-service satellite, and thus the terminal knows the common TA of the service satellite. Further, the terminal can determine the common TA of the non-service satellite based on the known common TA of the service satellite and the first indication information after receiving the first indication information.

[0107] Further, the terminal initiates random access to the non-service satellite based on the common TA of the non-service satellite. The terminal can initiate random access to the non-service satellite by using a contention-based random access method or a non-contention-based random access method, and the present application does not limit this.

[0108] In the embodiments of the present application, in the scenario that a terminal accesses a service satellite and expects to access a non-service satellite, the service satellite or the non-service satellite of the terminal can indicate the common TA of the non-service satellite to the terminal, and the indication manner can be: indicating the difference between the common TA of the service satellite and the common TA of the non-service satellite to the terminal, so as to indicate the common TA of the non-service satellite; or indicating the derivative between the common TA of the service satellite and the common TA of the non-service satellite to the terminal, so as to indicate the common TA of the non-service satellite. Compared with the manner of directly indicating the common TA of the non-service satellite, the method of the embodiments of the present application is beneficial to reducing the signaling overhead of indicating the common TA of the non-service satellite to the terminal. In other embodiments, the method 300 can further include more steps, such as S304 to S306 described below.

[0109] Optionally, before S302, the method 300 further includes S304: the service satellite sends second indication information to the terminal, and the second indication information is used to indicate the PCI of the non-service satellite.

[0110] The second indication information is, for example, the additional PCI index described above, and the additional PCI index corresponds to a PCI, which is a PCI of a non-service satellite, that is, the additional PCI index corresponds to a non-service satellite. The service cell sends the additional PCI index to the terminal, which means that the service cell indicates to the terminal that the non-service cell corresponding to the additional PCI index is activated.

[0111] When the service satellite activates a non-service satellite, for example, the service satellite can select a non-service satellite that meets a condition to jointly provide network service for the terminal.

[0112] The condition is, for example, that the network quality exceeds a first threshold value; or the number of served terminals is less than or equal to a second threshold value.

[0113] In the case that the non-service satellite sends the first indication information to the terminal, the terminal can determine which non-service satellite sends the first indication information based on the second indication information, and receive the first indication information sent by the non-service satellite based on the second indication information.

[0114] In a possible implementation manner, the first indication information is carried in a SIB. The terminal receives the first indication information sent by the non-service satellite based on the second indication information, including: the terminal receives the SSB sent by the non-service cell based on the second indication information, and further receives the SIB sent by the non-service cell, and obtains the first indication information from the SIB.

[0115] For example, the second indication information is the additional PCI index described above, after receiving the additional PCI index, the terminal determines the PCI corresponding to the additional PCI index, and further, the terminal can determine the non-serving satellite corresponding to the PCI. In this way, the terminal can receive the SSB corresponding to the non-serving satellite based on the PCI, and the SSB is used for the terminal to implement downlink synchronization. After implementing downlink synchronization, the terminal can successfully receive the subsequent message, such as SIB, sent by the satellite, and the SIB contains the first indication information, so that the terminal can obtain the first indication information by analyzing the SIB.

[0116] Optionally, before S301, the method 300 further includes S305: the terminal sends a request message to the serving satellite, and the request message is used to request the common TA of the non-serving satellite, or the request message is used to request to indicate the common TA of the non-serving satellite in a target manner. The target manner is to indicate the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or to indicate the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0117] In a possible implementation, after receiving the second indication information described above, the terminal determines that the serving satellite activates the serving satellite to jointly provide network services for the terminal. Based on this, the terminal can actively request the common TA of the non-serving satellite in order to access the non-serving satellite.

[0118] In another possible implementation, the terminal does not need to request the common TA of the non-serving satellite, and the terminal can request the serving satellite to indicate the common TA of the non-serving satellite in the target manner, and then the serving satellite or the non-serving satellite sends the first indication information to the terminal based on the request message. In this way, it is beneficial for the terminal to understand the content indicated by the first indication information sent by the serving satellite or the non-serving satellite.

[0119] If the non-serving satellite and the serving satellite negotiate that the non-serving satellite sends the first indication information to the terminal, after receiving the request message, the serving satellite forwards the request message to the non-serving satellite, or the serving satellite indicates the non-serving satellite to indicate the common TA of the non-serving satellite in the target manner.

[0120] For ease of description, in the following, the manner in which the satellite indicates the difference between the common TA of the serving satellite and the common TA of the non-serving satellite is referred to as manner one, and the manner in which the satellite indicates the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite is referred to as manner two.

[0121] For example, the above-mentioned target mode is described as "Option-K", K is 1 or 2. When K is 1, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode one. When K is 2, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode two.

[0122] For example, the terminal requests to indicate the common TA of the non-serving satellite in the mode one, and then the serving satellite sends first indication information to the terminal (or the non-serving satellite sends the first indication information to the terminal) after receiving the request message, the first indication information is used to indicate the difference between the common TA of the serving satellite and the common TA of the non-serving satellite. Taking the first indication information carried in the SIB as an example, the SIB includes a first information field, and the first information field is used to carry the first indication information. Since the terminal requests to indicate the common TA of the non-serving satellite in the mode one, the terminal can determine that the first indication information carried by the first information field is used to indicate the difference between the common TA of the serving satellite and the common TA of the non-serving satellite.

[0123] For example, the above-mentioned target mode is described as "Option-K", K is 1 or 2. When K is 1, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode one. When K is 2, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode two.

[0124] For example, the terminal requests to indicate the common TA of the non-serving satellite in the mode two, and then the serving satellite sends first indication information to the terminal (or the non-serving satellite sends the first indication information to the terminal) after receiving the request message, the first indication information is used to indicate the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite. Taking the first indication information carried in the SIB as an example, the SIB includes a second information field, and the second information field is used to carry the first indication information. Since the terminal requests to indicate the common TA of the non-serving satellite in the mode two, the terminal can determine that the first indication information carried by the second information field is used to indicate the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0125] For example, the above-mentioned target mode is described as "Option-K", K is 1 or 2. When K is 1, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode one. When K is 2, it means that the terminal requests to indicate the common TA of the non-serving cell in the above-mentioned mode two.

[0126] In a more direct indication mode, the terminal can also request to indicate the common TA of the non-serving cell in the mode three, which is a direct indication mode of the common TA of the non-serving cell, and the above-mentioned mode one and mode two are indirect indication modes of the common TA of the non-serving cell.

[0127] Optionally, the above target manner is described as "Option-K", when K takes value 3, it means that the terminal requests to indicate the common TA of the non-serving cell in manner three.

[0128] Optionally, before S301, the method 300 further includes S306: the serving satellite sends third indication information to the terminal, the third indication information is used to indicate that the common TA of the non-serving satellite will be indicated in a target manner, the target manner is: indicating the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or indicating the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0129] The third indication information is used to indicate that the common TA of the non-serving satellite will be indicated in a target manner, which can be understood as the third indication information is used to indicate the content indicated by the first indication information, the content is: the difference between the common TA of the serving satellite and the common TA of the non-serving satellite, or the derivative of the common TA of the non-serving satellite relative to the common TA of the serving satellite.

[0130] In a possible implementation, the serving satellite sends the third indication information to the terminal through a PDCCH command, that is, the third indication information is carried in the PDCCH command. The PDCCH command is used for the terminal to initiate random access, and the terminal initiates random access to the non-serving satellite based on the received common TA of the non-serving satellite after receiving the PDCCH command.

[0131] For example, the above target manner is described as "Option-K", and K takes value 1 or 2. When K takes value 1, it means that the serving satellite indicates to the terminal that the common TA of the non-serving cell will be indicated in the above manner one. When K takes value 2, it means that the serving satellite indicates to the terminal that the common TA of the non-serving cell will be indicated in the above manner two.

[0132] In the embodiment of the application, the serving satellite can indicate to the terminal through the third indication information that the common TA of the non-serving satellite will be indicated in a target manner before sending the first indication information. Similar to the description of S305, this is conducive to the terminal to understand the content indicated by the first indication information.

[0133] In a more direct indication manner, the serving satellite can also indicate to the terminal that the common TA of the non-serving cell will be indicated in the above manner three, the manner three is a manner of directly indicating the common TA of the non-serving cell, and the above manner one and manner two are manners of indirectly indicating the common TA of the non-serving cell.

[0134] Optionally, the above-mentioned target mode is described as "Option-K", when K takes value 3, it means that the serving satellite indicates to the terminal that the common TA of the non-serving cell will be indicated in mode 3.

[0135] It should be understood that the serving satellite can indicate to the terminal by configuration information that the common TA of any non-serving satellite can be indicated in the above-mentioned mode 1 or mode 2, or the above-mentioned mode 1 and mode 2 are predefined by protocol. In this way, when the serving satellite activates a non-serving satellite, the serving satellite can select one of the modes to indicate the common TA of the non-serving satellite, and the terminal can also request one of the modes to indicate the common TA of the non-serving satellite.

[0136] It should be understood that the various numbers involved in the embodiments of the present application are only used for differentiation for convenience of description, and do not limit the scope of the embodiments of the present application. The size of the serial numbers of the above-mentioned processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic.

[0137] It should be understood that in order to realize the functions in the above-mentioned embodiments, the satellite and the terminal include the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that the units and method steps of the examples described in combination with the embodiments disclosed in the present application can be realized in the form of hardware or hardware and computer software combination. Whether a certain function is realized in hardware or computer software driven hardware depends on the specific application scenario and design constraints of the technical solution.

[0138] The communication method according to the embodiments of the present application is described in detail above in combination with FIG. 3. The communication apparatus according to the embodiments of the present application will be described in detail below in combination with FIG. 4 and FIG. 5.

[0139] FIG. 4 and FIG. 5 are schematic block diagrams of the communication apparatus provided by the embodiments of the present application. These communication apparatuses can be used to realize the functions of the terminal or the serving satellite in the above-mentioned method embodiments, and thus can also realize the beneficial effects possessed by the above-mentioned method embodiments.

[0140] As shown in FIG. 4, the communication apparatus 400 includes a transceiver module 410 and a processing module 420. The transceiver module 410 can also be referred to as a communication interface or a communication module.

[0141] The apparatus 400 can be configured to perform the actions of the terminal or the service satellite in the above method embodiments. Alternatively, the apparatus 400 is a component (e.g., a chip) configured in the terminal or the service satellite. The processing module 420 is configured to perform the processing-related operations of the terminal or the service satellite in the above method embodiments. The transceiver module 410 is configured to perform the receiving and transmitting-related operations of the terminal or the service satellite in the above method embodiments.

[0142] Optionally, the transceiver module 410 can include a transmitting module and a receiving module. The transmitting module is configured to perform the transmitting operations in the above method embodiments. The receiving module is configured to perform the receiving operations in the above method embodiments.

[0143] It should be noted that the apparatus 400 can include the transmitting module but not the receiving module. Alternatively, the apparatus 400 can include the receiving module but not the transmitting module. Specifically, whether the apparatus 400 includes the transmitting module and the receiving module can depend on whether the apparatus 400 performs the transmitting actions and the receiving actions in the above solutions.

[0144] Optionally, the apparatus 400 is configured to perform the actions of the terminal or the service satellite in the above embodiment shown in FIG. 3. For details, refer to the related description in the above embodiment shown in FIG. 3, which will not be repeated here.

[0145] Optionally, the apparatus 400 can further include a storage module, which can be configured to store data, and / or store computer programs or instructions. The processing module 420 can read the computer programs / instructions and / or data in the storage module, so that the apparatus 400 implements the above method embodiments.

[0146] When the apparatus 400 is configured to implement the functions of the terminal in the method embodiment shown in FIG. 3, the transceiver module 410 is configured to: receive first indication information from a satellite, the satellite being a service satellite or a non-service satellite of the terminal, the first indication information being used to indicate: a difference between a common TA of the service satellite and a common TA of the non-service satellite, or a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0147] Optionally, the transceiver module 410 is further configured to: receive second indication information from the service satellite, the second indication information being used to indicate a PCI of the non-service satellite.

[0148] Optionally, the transceiver module 410 is further configured to: receive the first indication information from the satellite based on the second indication information.

[0149] Optionally, the transceiver module 410 is further configured to: receive an SSB from the non-service cell based on the PCI; and receive the first indication information from the satellite after performing downlink synchronization based on the SSB.

[0150] Optionally, the transceiver 410 is further configured to receive, from the terminal, a request message, the request message being used to request the common TA of the non-service satellite, or being used to request to indicate the common TA of the non-service satellite in a target manner, the target manner being: indicating a difference between the common TA of the service satellite and the common TA of the non-service satellite, or indicating a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0151] Optionally, the transceiver 410 is further configured to receive, from the terminal, a request message, the request message being used to request the common TA of the non-service satellite, or being used to request to indicate the common TA of the non-service satellite in a target manner, the target manner being: indicating a difference between the common TA of the service satellite and the common TA of the non-service satellite, or indicating a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0152] When the apparatus 400 is configured to implement the function of the service satellite in the method embodiment as shown in FIG. 3, the processing module 420 is configured to generate first indication information, the first indication information being used to indicate: a difference between the common TA of the service satellite and the common TA of the non-service satellite, or a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite. The transceiver 410 is configured to transmit the first indication information to the terminal.

[0153] Optionally, the transceiver 410 is further configured to transmit, to the terminal, second indication information, the second indication information being used to indicate the PCI of the non-service satellite.

[0154] Optionally, the transceiver 410 is further configured to receive, from the terminal, a request message, the request message being used to request the common TA of the non-service satellite, or being used to request to indicate the common TA of the non-service satellite in a target manner, the target manner being: indicating a difference between the common TA of the service satellite and the common TA of the non-service satellite, or indicating a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0155] Optionally, the transceiver 410 is further configured to receive, from the terminal, a request message, the request message being used to request the common TA of the non-service satellite, or being used to request to indicate the common TA of the non-service satellite in a target manner, the target manner being: indicating a difference between the common TA of the service satellite and the common TA of the non-service satellite, or indicating a derivative of the common TA of the non-service satellite relative to the common TA of the service satellite.

[0156] For more details of the transceiver 410, please refer to the description of the method embodiment as shown in FIG. 3, which will not be repeated here. The processing module 420 can be implemented by a processor, and the transceiver 410 can be implemented by a transceiver.

[0157] The first indication information, the second indication information, the third indication information, and the request message are described in detail in the method embodiments above, and thus are not described herein.

[0158] FIG. 5 is a schematic block diagram of another communication apparatus 500 according to an embodiment of the present application. As shown in FIG. 5, the apparatus 500 includes one or more processors 510 and interface circuitry 520. The one or more processors 510 and the interface circuitry 520 are coupled to each other. It can be understood that the interface circuitry 520 can be a transceiver or an input / output interface. Optionally, the apparatus 500 can further include a memory 530 for storing instructions executed by the processor 510, or for storing input data required by the processor 510 to execute instructions, or for storing data generated by the processor 510 after executing instructions. Sometimes, the interface circuitry 520 can also be understood as a part of the one or more processors 510, and in this case, the apparatus 500 includes the one or more processors 510.

[0159] The one or more processors 510 and the memory 530 can be separately arranged or integrally arranged, which is not limited in the present application.

[0160] When the apparatus 500 is used to implement the method shown in FIG. 3, the one or more processors 510 are configured to implement the functions of the processing module 420, and the interface circuitry 520 is configured to implement the functions of the transceiver module 410.

[0161] When the apparatus 500 is a chip applied to a terminal, the chip of the terminal implements the functions of the terminal in the method embodiments. The chip of the terminal receives information from a service satellite, which can be understood as that the information is first received by other modules (such as a radio frequency module or an antenna) in the terminal, and then transmitted to the chip of the terminal by the other modules. The chip of the terminal transmits information to the service satellite, which can be understood as that the information is first transmitted to other modules (such as a radio frequency module or an antenna) in the terminal, and then transmitted to the service satellite by the other modules.

[0162] When the apparatus 500 is a chip applied to a service satellite, the chip of the service satellite implements the functions of the service satellite in the method embodiments. The chip of the service satellite receives information from a terminal, which can be understood as that the information is first received by other modules (such as a radio frequency module or an antenna) in the service satellite, and then transmitted to the chip of the service satellite by the other modules. The chip of the service satellite transmits information to the terminal, which can be understood as that the information is first transmitted to other modules (such as a radio frequency module or an antenna) in the service satellite, and then transmitted to the terminal by the other modules.

[0163] The embodiment of the present application further provides a computer readable storage medium for storing a computer program, which can enable a computer to execute the communication method when the computer program is run on the computer. Alternatively, the computer program comprises instructions for implementing the communication method.

[0164] The embodiment of the present application further provides a computer program product comprising a computer program or instructions, which can enable a computer to execute the communication method when the computer program or instructions are run on the computer.

[0165] The embodiment of the present application further provides a chip comprising at least one processor, which can support implementation of the communication method, for example, receiving or processing data involved in the communication method.

[0166] It should be understood that, in the embodiment of the present application, the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0167] In the implementation process, each step of the above method can be completed by integrated logic circuits of hardware in the processor or instructions in the form of software. The steps of the method disclosed in the embodiment of the present application can be directly embodied as execution completed by a hardware processor, or executed by a combination of hardware and software modules in the processor. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium in the art. The storage medium is located in the memory, and the processor executes the instructions in the memory to complete the steps of the above method in combination with the hardware thereof. To avoid repetition, it will not be described in detail here.

[0168] Those skilled in the art can realize that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0169] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the system, device and module described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0170] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the modules is only a logical function division, and actual implementation can have another division manner, for example, a plurality of modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed modules can be indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0171] The modules described as separate components can or can not be physically separated, and the components shown as modules can or can not be physical modules, i.e. can be located in one place, or can be distributed to a plurality of network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0172] In addition, the functional modules in each embodiment of the present application can be integrated in one processing module, or each module can exist physically, or two or more modules can be integrated in one module.

[0173] If the functions are realized in the form of software function modules 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 present application essentially or the part of the prior art or the part of the technical solutions can be embodied in the form of software product, and the computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and various program code storage media.

[0174] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method comprises: receiving first indication information from a satellite, the satellite being a serving satellite or a non-serving satellite of a terminal, the first indication information being used to indicate a difference between a common timing advance of the serving satellite and a common timing advance of the non-serving satellite, or a derivative of the common timing advance of the non-serving satellite relative to the common timing advance of the serving satellite; determining the common timing advance of the non-serving satellite based on the first indication information and the common timing advance of the serving satellite.

2. The method of claim 1, wherein, The derivative comprises a first-order derivative and / or a second-order derivative.

3. The method according to claim 1 or 2, characterized in that, Before the receiving first indication information from a satellite, the method further comprises: receiving second indication information from the serving satellite, the second indication information being used to indicate a physical cell identity, PCI, of the non-serving satellite.

4. The method of claim 3, wherein, The satellite is a non-serving satellite of the terminal. The receiving first indication information from a satellite comprises: receiving the first indication information from the satellite based on the second indication information.

5. The method of claim 4, wherein, The receiving the first indication information from the satellite based on the second indication information comprises: receiving a synchronization signal block, SSB, from the non-serving cell based on the PCI; after implementing downlink synchronization based on the SSB, receiving the first indication information from the satellite.

6. The method according to any one of claims 1 to 5, characterized in that, The first indication information is carried in a system information block, SIB.

7. The method according to any one of claims 1 to 6, characterized in that, Before the receiving first indication information from a satellite, the method further comprises: sending a request message to the serving satellite, the request message being used to request the common timing advance of the non-serving satellite, or being used to request to indicate the common timing advance of the non-serving satellite in a target manner, the target manner being to indicate a difference between the common timing advance of the serving satellite and the common timing advance of the non-serving satellite, or to indicate a derivative of the common timing advance of the non-serving satellite relative to the common timing advance of the serving satellite.

8. The method according to any one of claims 1 to 6, characterized in that, Before the receiving first indication information from a satellite, the method further comprises: receiving third indication information from the serving satellite, the third indication information being used to indicate that the common timing advance of the non-serving satellite will be indicated in a target manner, the target manner being to indicate a difference between the common timing advance of the serving satellite and the common timing advance of the non-serving satellite, or to indicate a derivative of the common timing advance of the non-serving satellite relative to the common timing advance of the serving satellite.

9. The method of claim 8, wherein, The third indication information is carried in a physical downlink control channel, PDCCH, order.

10. A communication method characterized by comprising: The method comprises: generating first indication information, the first indication information being used to indicate a difference between a common timing advance of a serving satellite of a terminal and a common timing advance of a non-serving satellite of the terminal, or a derivative of the common timing advance of the non-serving satellite relative to the common timing advance of the serving satellite; sending the first indication information to the terminal.

11. The method of claim 10, wherein, The derivative comprises a first-order derivative and / or a second-order derivative.

12. The method according to claim 10 or 11, characterized in that, Before the sending the first indication information to the terminal, the method further comprises: The second indication information is used to indicate a physical cell identity, PCI, of the non-service satellite.

13. The method according to any one of claims 10 to 12, characterized in that, The first indication information is carried in a system information block, SIB.

14. The method according to any one of claims 10 to 13, characterized in that, Before the first indication information is generated, the method further includes: receiving a request message from the terminal, the request message being used to request a common timing advance of the non-service satellite, or being used to request to indicate the common timing advance of the non-service satellite in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite relative to the common timing advance of the service satellite.

15. The method according to any one of claims 10 to 13, characterized in that, Before the first indication information is generated, the method further includes: sending third indication information to the terminal, the third indication information being used to indicate that the common timing advance of the non-service satellite will be indicated in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite relative to the common timing advance of the service satellite.

16. The method of claim 15, wherein, The third indication information is carried in a physical downlink control channel, PDCCH, order.

17. A communications device, characterized by comprise: a transceiver module and a processing module; the transceiver module is configured to: receive first indication information from a satellite, the satellite being a service satellite or a non-service satellite of a terminal, the first indication information being used to indicate: a difference between a common timing advance of the service satellite and a common timing advance of the non-service satellite, or a derivative of the common timing advance of the non-service satellite relative to the common timing advance of the service satellite; the processing module is configured to: determine the common timing advance of the non-service satellite based on the first indication information and the common timing advance of the service satellite.

18. The apparatus of claim 17, wherein, The derivative comprises: a first-order derivative and a second-order derivative.

19. The apparatus of claim 17 or 18, wherein, The transceiver module is configured to: receive second indication information from the service satellite, the second indication information being used to indicate a physical cell identity, PCI, of the non-service satellite.

20. The apparatus of claim 19, wherein, The transceiver module is configured to: receive the first indication information from the satellite based on the second indication information.

21. The apparatus of claim 20, wherein, The transceiver module is configured to: receive a synchronization signal block, SSB, from the non-service cell based on the PCI; after downlink synchronization is implemented based on the SSB, receive the first indication information from the satellite.

22. The apparatus of any one of claims 17-21, wherein, The first indication information is carried in a system information block, SIB.

23. The apparatus of any one of claims 17-22, wherein, The transceiver module is configured to: send a request message to the service satellite, the request message being used to request a common timing advance of the non-service satellite, or being used to request to indicate the common timing advance of the non-service satellite in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite relative to the common timing advance of the service satellite.

24. The apparatus of any one of claims 17-22, wherein, The transceiver module is configured to: receive third indication information from the service satellite, the third indication information being used to indicate that the common timing advance of the non-service satellite will be indicated in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite with respect to the common timing advance of the service satellite.

25. The apparatus of claim 24, wherein, The third indication information is carried in a physical downlink control channel (PDCCH) order.

26. A communications device, characterized by comprise: a processing module and a transceiver module; The processing module is configured to: generate first indication information, the first indication information being used to indicate: a difference between the common timing advance of a service satellite of a terminal and the common timing advance of a non-service satellite of the terminal, or a derivative of the common timing advance of the non-service satellite with respect to the common timing advance of the service satellite; The transceiver module is configured to: send the first indication information to the terminal.

27. The apparatus of claim 26, wherein, The derivative comprises: a first-order derivative and a second-order derivative.

28. The apparatus of claim 26 or 27, wherein, The transceiver module is configured to: send second indication information to the terminal, the second indication information being used to indicate a physical cell identity (PCI) of the non-service satellite.

29. The apparatus of claim 26 or 28, wherein, The first indication information is carried in a system information block (SIB).

30. The apparatus of any one of claims 26-29, wherein, The transceiver module is configured to: receive a request message from the terminal, the request message being used to request the common timing advance of the non-service satellite, or being used to request that the common timing advance of the non-service satellite be indicated in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite with respect to the common timing advance of the service satellite.

31. The apparatus of any one of claims 26-29, wherein, The transceiver module is configured to: send third indication information to the terminal, the third indication information being used to indicate that the common timing advance of the non-service satellite will be indicated in a target manner, the target manner being: indicating a difference between the common timing advance of the service satellite and the common timing advance of the non-service satellite, or indicating a derivative of the common timing advance of the non-service satellite with respect to the common timing advance of the service satellite.

32. The apparatus of claim 31, wherein, The third indication information is carried in a physical downlink control channel (PDCCH) order.

33. A communications device, characterized by comprise at least one processor coupled with a memory, the memory being used to store programs or instructions, when the programs or instructions are executed by the at least one processor, causing the method in any one of claims 1 to 9 to be executed, or causing the method in any one of claims 10 to 16 to be executed.

34. A computer-readable storage medium, characterized in that, a computer program for storing, when the computer program is run on a computer, causing the method in any one of claims 1 to 9 to be executed, or causing the method in any one of claims 10 to 16 to be executed.

35. A computer program product, characterised in that, comprise: A computer program or instructions, which, when executed, cause a method as claimed in any one of claims 1 to 9 to be performed, or cause a method as claimed in any one of claims 10 to 16 to be performed.

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