Communication method and apparatus

Abstract

A communication method and apparatus, applied to a satellite communication system. The method comprises: a first satellite determines first information, and sends the first information. The first information comprises synchronization information of at least one second satellite, and the synchronization information of each second satellite comprises at least one synchronization index. The first satellite can plan a method for a plurality of second satellites to send synchronization signals, for example, synchronization indexes corresponding to the synchronization signals sent by the second satellites are different. The method can reduce or even avoid the interference among synchronization signals of satellites, thereby improving the communication performance.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on January 22, 2024, with application number 202410089113.7 and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of satellite technology, and in particular to a communication method and device. Background Art

[0004] Considering the network's coverage and capacity, multi-layer constellation networks are a new development trend in satellite communication networks. In a multi-layer constellation network, multiple satellites are deployed at different orbital altitudes, and satellites at the same orbital altitude can be considered a layer. Each satellite independently transmits a synchronization signal and physical downlink broadcast channel block (SSB). Terminal devices determine which satellite to connect to based on the received SSB. Each layer of satellites is relatively independent and moves at high speeds. If each satellite independently transmits SSB, the SSBs of multiple satellites may correspond to the same geographic area, resulting in significant interference between the SSBs of multiple satellites. Summary of the Invention

[0005] The embodiments of the present application provide a communication method and apparatus for rationally planning the way in which satellites transmit SSBs, thereby reducing or even avoiding SSB interference between multiple satellites and improving communication performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] In a first aspect, embodiments of the present application provide a communication method that can be performed by a first communication device. The first communication device can be a component, assembly, or the like used to implement satellite functionality. For example, the first communication device can be a satellite, or a unit / module, circuit, or chip within a satellite. The method provided in the first aspect is described below using the first communication device being the first satellite itself as an example.

[0008] The communication method includes: a first satellite determines first information and sends the first information, wherein the first information includes synchronization information of at least one second satellite, and the synchronization information of each second satellite includes at least one synchronization index.

[0009] Relatively speaking, the first satellite can be the anchor satellite of the terminal device, and the second satellite can be a satellite within the coverage area of ​​the first satellite, also known as a sub-satellite or slave satellite. The first satellite can schedule the second satellite. A terminal device within the coverage area (or coverage area) of the first satellite can access any second satellite within the coverage area of ​​the first satellite. The synchronization index can indicate a synchronization signal. This method uses the first satellite to plan how multiple second satellites transmit synchronization signals. For example, the first satellite can instruct different second satellites to transmit synchronization signals indicated by different synchronization indices. This method can reduce or even avoid interference between synchronization signals between satellites, thereby improving communication performance.

[0010] In one implementation, the synchronization information of each second satellite further includes a time corresponding to at least one synchronization index.

[0011] In this solution, the first satellite can also schedule the timing of synchronization signal transmissions by each second satellite. For example, different second satellites can transmit different synchronization signals at the same time, or different second satellites can transmit the same synchronization signal at different times, or different second satellites can transmit different synchronization signals at different times. By scheduling the timing of synchronization signal transmissions by each second satellite, interference between synchronization signals between multiple second satellites can be reduced while conserving resources for transmitting synchronization signals, ensuring maximum coverage.

[0012] In one implementation, the first information further includes: ephemeris information of at least one second satellite, identification information of at least one second satellite, or identification information of at least one transmission reception point (TRP), where one TRP corresponds to one second satellite.

[0013] Both the second satellite's identification information and the TRP's identification information indirectly indicate the second satellite's ephemeris information. By including information related to the ephemeris information of at least one second satellite within the first message, the second satellite receiving the first message can determine which synchronization information in the first message belongs to it. This allows the first satellite to broadcast the first message, reducing signaling overhead.

[0014] In one implementation, the at least one second satellite includes multiple second satellites, and the cell identifiers corresponding to the multiple second satellites are the same. This allows a terminal device to remain within the same cell when moving from one second satellite's coverage area to another, eliminating the need for a cell handover. This solution reduces the number of cell handovers required by the terminal device and improves communication efficiency.

[0015] In one implementation, the method further includes: the first satellite transmitting second information to a second satellite A among the plurality of second satellites, the second information including first time information and a first synchronization index, for instructing the second satellite A to transmit a synchronization signal indicated by the first synchronization index at a time indicated by the first time information. The time indicated by the first time information does not fall within a time at which a second satellite B among the plurality of second satellites provides a service based on the first synchronization index.

[0016] In this solution, the second satellite B cannot provide services to the terminal device based on the first synchronization index at the information indicated by the first time information, or the second satellite B cannot send the synchronization signal indicated by the first synchronization index at the time indicated by the first time information. In this case, the first satellite may decide to have the second satellite A replace the second satellite B to provide services to the terminal device using the first synchronization index at the time indicated by the first time information, thereby reducing the impact on the data transmission performance of the terminal device.

[0017] In one implementation, the method further includes: the first satellite receiving third information from the second satellite B, where the third information includes first time information and a first synchronization index.

[0018] In this scheme, when the information indicated by the first time information of the second satellite B cannot provide services for the terminal device based on the first synchronization index, the third information is reported to the first satellite, so that the first satellite reselects the second satellite A instead of the second satellite B to serve the terminal device, thereby reducing the impact on the data transmission performance of the terminal device.

[0019] In a second aspect, embodiments of the present application provide a communication method that can be performed by a second communication device. The second communication device can be a component, assembly, or the like used to implement satellite functionality. For example, the second communication device can be a satellite, or a unit / module, circuit, or chip within a satellite. The method provided in the second aspect is described below using the second communication device being a second satellite itself as an example.

[0020] The communication method includes: a second satellite determines a first synchronization signal and sends the first synchronization signal. The first synchronization signal includes a second synchronization index, the second synchronization index is associated with second ephemeris information, and the second ephemeris information is different from the ephemeris information associated with synchronization indexes corresponding to other second satellites.

[0021] In one implementation, the first synchronization signal further includes: second ephemeris information or a first association relationship, where the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information.

[0022] In one implementation, the method further includes: the second satellite receiving first information from the first satellite, the first information including synchronization information of at least one second satellite, and the synchronization information of each second satellite including at least one synchronization index.

[0023] In one implementation, the synchronization information of each second satellite further includes a time corresponding to at least one synchronization index.

[0024] In one implementation, the first information further includes: ephemeris information of at least one second satellite, identification information of at least one second satellite, or identification information of at least one TRP, where one TRP corresponds to one second satellite.

[0025] In one implementation, the method further includes: a second satellite receiving second information from the first satellite, and transmitting a second synchronization signal at a time indicated by the first time information. The second information includes the first time information and a first synchronization index, which is used to instruct the second satellite to transmit a synchronization signal indicated by the first synchronization index at the time indicated by the first time information. The time indicated by the first time information does not fall within a time when another second satellite provides a service based on the first synchronization index. The second synchronization signal includes the first synchronization index.

[0026] In one implementation, the method further includes: the second satellite sending fourth information to the first satellite, the fourth information including second time information and a third synchronization index, and the third synchronization index cannot provide service at the time indicated by the second time information.

[0027] Regarding the beneficial effects of the second aspect and each implementation method, reference may be made to the beneficial effects of the aforementioned first aspect and each implementation method, which will not be repeated here.

[0028] In a third aspect, embodiments of the present application provide a communication method that can be performed by a third communication device. The third communication device can be a combination of components, parts, etc. used to implement the functions of a terminal device. For example, the third communication device is a terminal device, or the third communication device is a unit / module, circuit, or chip within the terminal device. The method provided in the second aspect is described below using the third communication device as an example of the terminal device itself.

[0029] The communication method includes: a terminal device receiving a first synchronization signal, the first synchronization signal including a second synchronization index; determining second ephemeris information based on the second synchronization index and a first association relationship, the first association relationship being an association relationship between at least one synchronization index and at least one ephemeris information; determining a timing advance (TA) amount based on the second ephemeris information; and sending a random access preamble based on the TA amount.

[0030] Regarding the beneficial effects of the second aspect and each implementation method, reference may be made to the beneficial effects of the aforementioned first aspect and each implementation method, which will not be repeated here.

[0031] In a fourth aspect, embodiments of the present application provide a communication method that can be performed by a first communication device. The first communication device can be a component, assembly, or the like used to implement satellite functions. For example, the first communication device can be a satellite, or a unit / module, circuit, or chip within a satellite. The method provided in the first aspect will be described below using the first communication device as an example, namely, the first satellite itself.

[0032] The communication method includes: a first satellite using resources within a first resource set to transmit a third synchronization signal; receiving a first random access preamble from a terminal device; determining a second satellite A based on the first random access preamble and a second association, and transmitting a random access response message to the terminal device. The second association includes an association between multiple sub-resource sets and multiple second satellites, the resources of the first random access preamble belonging to a first sub-resource set of the multiple sub-resource sets, and the second satellite A belonging to the multiple second satellites. The random access response message includes ephemeris information and resource information of the second satellite A, the resource information indicating the resources used by the second satellite A to transmit the synchronization signal.

[0033] In this solution, the first resource set is a set of random access resources corresponding to the first satellite. The first resource set can be divided into multiple sub-resource sets, each of which corresponds to a second satellite, and a second satellite can correspond to one or more sub-resource sets. When a terminal device has a data transmission requirement, it can select resources from the sub-resource set corresponding to the second satellite corresponding to the terminal device to send a first random access preamble. In this way, the first satellite can determine which second satellite is within the coverage area of ​​the terminal device based on the resources used by the first random access preamble, thereby scheduling the second satellite to provide service to the terminal device. With this solution, if the terminal device does not have a data transmission requirement, there is no need to schedule any second satellite to send a synchronization signal, which can reduce the transmission of unnecessary synchronization signals, thereby conserving resources and reducing satellite power consumption.

[0034] In one implementation, the method further includes: the first satellite sends fifth information, the fifth information indicates a second association relationship, the second association relationship also includes an association relationship between multiple sub-resource sets and the first resource set, wherein the multiple sub-resource sets are obtained by dividing the first resource set.

[0035] The first satellite can notify the terminal device of the association relationship between the first resource set and multiple sub-resource sets through dynamic signaling, which is more flexible.

[0036] In a fifth aspect, embodiments of the present application provide a communication method that can be performed by a third communication device. The third communication device can be a combination of components, parts, etc. used to implement the functions of a terminal device. For example, the third communication device is a terminal device, or the third communication device is a unit / module, circuit, or chip within the terminal device. The method provided in the second aspect is described below using the third communication device as an example of the terminal device itself.

[0037] The communication method includes: a terminal device receives a third synchronization signal from a first satellite, where the third synchronization signal is sent using resources within a first resource set; the terminal device sends a first random access preamble to the first satellite, and receives a random access response message, where the random access response message includes ephemeris information and resource information of a second satellite, where the resource information is used to indicate the resources used by the second satellite to send the synchronization signal; and the terminal device receives the synchronization signal from the second satellite on the resources indicated by the resource information.

[0038] In one implementation, the method further includes: the terminal device determining a first sub-resource set based on the first resource set and a second association relationship, where the second association relationship includes an association relationship between the first resource set and multiple sub-resource sets, the multiple sub-resource sets being obtained by dividing the first resource set, and the first sub-resource set belonging to the multiple sub-resource sets. The terminal device sending a first random access preamble to the first satellite includes: the terminal device sending the first random access preamble to the first satellite using resources within the first sub-resource set.

[0039] Regarding the fifth aspect and the beneficial effects of each implementation method, reference can be made to the beneficial effects of the aforementioned fourth aspect and its various implementation methods, which will not be repeated here.

[0040] In a sixth aspect, an embodiment of the present application provides a communication method that can be performed by a first communication device, a second communication device, and a third communication device. The first communication device and the second communication device can be a combination of devices, components, etc. used to implement satellite functions. For example, the first communication device is a first satellite, or the first communication device is a unit / module, circuit, or chip inside the first satellite. The second communication device is a second satellite, or the second communication device is a unit / module, circuit, or chip inside the second satellite. The third communication device can be a combination of devices, components, etc. used to implement the functions of a terminal device. For example, the third communication device is a terminal device, or the third communication device is a unit / module, circuit, or chip inside the terminal device.

[0041] For example, taking the first communication device as the first satellite itself, the second communication device as the second satellite itself, and the third communication device as a terminal device as an example, the communication method includes: the first satellite transmits first information, the first information including synchronization information of at least one second satellite, the synchronization information of each second satellite including at least one synchronization index; the second satellite transmits a first synchronization signal, the first synchronization signal including a second synchronization index, the second synchronization index being associated with second ephemeris information, the second ephemeris information being different from the ephemeris information associated with synchronization indexes corresponding to other second satellites; the terminal device receives the first synchronization signal, the first synchronization signal including the second synchronization index; determines second ephemeris information based on the second synchronization index and a first association, the first association being an association between at least one synchronization index and at least one ephemeris information; determines a TA amount based on the second ephemeris information, and transmits a random access preamble based on the TA amount.

[0042] For another example, the first satellite uses resources within the first resource set to send a third synchronization signal, the terminal device receives the third synchronization signal, and sends a first random access preamble to the first satellite; the first satellite receives the first random access preamble and sends a random access response message to the terminal device, and the random access response message includes ephemeris information and resource information of the second satellite, and the resource information is used to indicate the resources for the second satellite to send the synchronization signal; the terminal device receives the synchronization signal from the second satellite on the resources indicated by the resource information.

[0043] In the seventh aspect, an embodiment of the present application provides a communication device, which has the function of implementing the behavior in the method example of any aspect from the first aspect to the fifth aspect. The beneficial effects can be found in the relevant description of the first aspect or the fourth aspect and will not be repeated here. For example, the communication device can be the first satellite in the first aspect or the fourth aspect, or the communication device can be a device that can support the satellite to implement the functions required by the method provided in the first aspect or the fourth aspect, for example, the communication device can be a chip or chip system in the satellite. For another example, the communication device can be the second satellite in the second aspect, or the communication device can be a device that can support the satellite to implement the functions required by the method provided in the second aspect, for example, the communication device can be a chip or chip system in the satellite. For example, the communication device can be the terminal device in the third aspect or the fifth aspect, or the communication device can be a device that can support the terminal device to implement the functions required by the method provided in the third aspect or the fifth aspect, for example, the communication device can be a chip or chip system in the terminal device.

[0044] In one possible design, the communication device includes a baseband device and a radio frequency device.

[0045] In one possible design, the communication device includes corresponding means (means) or modules for executing the method of any aspect of the first aspect to the fifth aspect. For example, the communication device: includes a processing unit (sometimes also referred to as a processing module or processor) and / or a transceiver unit (sometimes also referred to as a transceiver module or transceiver). The transceiver unit can realize the sending function and the receiving function. When the transceiver unit realizes the sending function, it can be called a sending unit (sometimes also referred to as a sending module). When the transceiver unit realizes the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional unit, which is called a transceiver unit, and the functional unit can realize the sending function and the receiving function; or, the sending unit and the receiving unit can be different functional units, and the transceiver unit is a general term for these functional units. These units (modules) can perform the corresponding functions in the method examples of any aspect of the first aspect to the fifth aspect above. Please refer to the detailed description in the method examples for details, which will not be repeated here.

[0046] In an eighth aspect, an embodiment of the present application provides a communication device, which may be the communication device in the seventh aspect of the above-mentioned embodiment, or a chip or chip system provided in the communication device in the seventh aspect. The communication device includes a communication interface and a processor, and optionally, further includes a memory. The memory is used to store computer programs or instructions or data, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions or data, the communication device executes the method executed by the terminal device in the above-mentioned method embodiment. For example, the communication device may be a terminal device or a functional module in the terminal device, such as a baseband chip and a radio frequency chip. Alternatively, when the processor reads the computer program or instructions or data, the communication device executes the method executed by the first satellite or the second satellite in the above-mentioned method embodiment. For example, the communication device may be a satellite or a functional module in a satellite, such as a baseband chip and a radio frequency chip.

[0047] In the ninth aspect, an embodiment of the present application provides a chip system, which includes a processor and may also include a communication interface for implementing the method described in any of the first to fifth aspects. Optionally, the chip system also includes a memory. The memory is used to store computer programs (also referred to as codes, or instructions). The processor is used to call and run the computer program from the memory so that the device equipped with the chip system executes the method in any of the first to fifth aspects and any of its implementations. The chip system can be composed of chips, or it can include chips and other discrete devices.

[0048] In a tenth aspect, an embodiment of the present application provides a communication device comprising an input / output interface and a logic circuit. The input / output interface is used to input and / or output information. The input / output interface can be an interface circuit, an output circuit, an input circuit, a pin, or related circuits. The logic circuit is used to execute the method described in any of aspects 1 to 5.

[0049] In a specific implementation, the communication device may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the logic circuit may be a transistor, a gate circuit, a trigger, or various logic circuits. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to and transmitted by a transmitter. The input circuit and the output circuit may be the same circuit, which functions as an input circuit and an output circuit, respectively, at different times. This application does not limit the specific implementation of the input and output interfaces and logic circuits.

[0050] In one implementation, when the communication device is a wireless communication device, the wireless communication device may be a terminal device such as a mobile phone, or a network device such as a satellite. The interface circuit may be a radio frequency processing chip in the wireless communication device, and the processing circuit may be a baseband processing chip in the wireless communication device.

[0051] In an eleventh aspect, an embodiment of the present application provides a communication system, comprising a terminal device and multiple satellites, wherein the multiple satellites include a first satellite and a second satellite. The first satellite is configured to implement the functions of the method described in the first aspect, the second satellite is configured to implement the functions of the method described in the second aspect, and the terminal device is configured to implement the functions of the method described in the third aspect. Alternatively, the first satellite is configured to implement the functions of the method described in the fourth aspect, and the terminal device is configured to implement the functions of the method described in the fifth aspect.

[0052] In the twelfth aspect, an embodiment of the present application provides a computer-readable storage medium, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, the method described in any aspect of the first to fifth aspects and any implementation method thereof is implemented.

[0053] In a thirteenth aspect, an embodiment of the present application further provides a computer program product comprising instructions, which, when executed on a computer, enables the method described in any of the above-mentioned first to fifth aspects and any of their implementation methods to be implemented.

[0054] The beneficial effects of the sixth to thirteenth aspects and their implementation methods mentioned above can refer to the beneficial effects of the first aspect or the fourth aspect and any one of their implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG1 is a schematic diagram of an architecture of a communication system provided in an embodiment of the present application;

[0056] FIG2 is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0057] FIG3 is another schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0058] FIG4 is a flow chart of a communication method 400 provided in an embodiment of the present application;

[0059] FIG5 is a schematic diagram of a staring service during satellite movement provided by an embodiment of the present application;

[0060] FIG6 is a flow chart of a communication method 600 provided in an embodiment of the present application;

[0061] FIG7 is a network architecture diagram of a satellite communication system provided in an embodiment of the present application;

[0062] FIG8 is a flow chart of a communication method 800 provided in an embodiment of the present application;

[0063] FIG9 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0064] FIG10 is another schematic diagram of the structure of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] The method provided in the embodiment of the present application can reduce or even avoid interference of synchronization signals between multiple satellites, thereby improving communication performance. The solution provided in the embodiment of the present application is described below with reference to the accompanying drawings.

[0066] The technical solutions provided in the embodiments of the present application can be applied to non-terrestrial network (NTN) systems. An NTN system is a communication system formed by networking non-terrestrial network devices. Non-terrestrial network devices include, for example, satellites, high altitude platform stations (HAPS), drones, and other devices. The non-terrestrial network devices involved in the embodiments of the present application are not limited to the above examples. The non-terrestrial network devices in the present application can also be referred to as aerial network devices. In the embodiments of the present application, the satellite communication system can be integrated with a traditional mobile communication system. The mobile communication system can be a long-term evolution (LTE) communication system, a sixth-generation (5G) mobile communication system (for example, a new radio (NR) system), or can also be applied to other next-generation mobile communication systems, or other similar communication systems. Other similar communication systems may include wireless fidelity (WIFI), vehicle to everything (V2X), Internet of Things (IoT) systems, narrowband Internet of Things (NB-IoT) systems, and the like.

[0067] As an example, please refer to Figure 1, which is a schematic diagram of a network architecture of a communication system provided in an embodiment of the present application. The communication system includes a radio access network 100 and a core network 200. Optionally, the communication system may also include the Internet (Figure 1 takes this as an example).

[0068] Among them, the wireless access network 100 may include at least one network device (such as 110a, 110b and 110c in Figure 1) and at least one terminal device (such as 120a-120j in Figure 1). The network architecture shown in Figure 1 is only a schematic, and the number of terminal devices and / or network devices may be less or more. The communication system described in the embodiment of the present application is to more clearly illustrate the technical solution of the embodiment of the present application, and does not constitute a limitation on the communication system to which the embodiment of the present application is applicable. For example, the communication system may also include other devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1. It is known to those skilled in the art that with the evolution of network architecture, the technical solutions provided in the embodiment of the present application are also applicable to similar technical problems. When the technical solutions of the embodiment of the present application are applied to other communication systems, the devices, components, modules, etc. in the embodiment can be replaced with corresponding devices, components, modules in other communication systems without limitation.

[0069] In the embodiments of the present application, the network device refers to a radio access network (RAN) device. The RAN may be a 3GPP-related cellular system, such as a 5G / new radio (NR) mobile communication system, or a future-oriented evolution system. The RAN may also be an open access network (open RAN, O-RAN or ORAN), a cloud radio access network (CRAN), or a virtualized RAN (vRAN). The RAN may also be a communication system that integrates two or more of the above systems. The RAN device may also be referred to as a RAN node, a RAN entity, or an access node.

[0070] In one possible scenario, a RAN node can be a base station, an evolved NodeB (eNodeB), an access point (AP), a Transmitter Relay (TRP), a next-generation NodeB (gNB), or a base station in a future mobile communication system. A RAN node can be a macro base station, a micro base station, an indoor station, a relay node, a donor node / host node, or a wireless controller. A RAN node can also be a server, a wearable device, a vehicle, or an onboard device. For example, a RAN node in V2X technology can be a roadside unit (RSU).

[0071] In another possible scenario, the RAN node may be a module or unit that performs part of the functions of the base station; or multiple RAN nodes collaborate to assist terminal devices in achieving wireless access, and different RAN nodes respectively perform part of the functions of the base station. For example, the RAN node may be a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). The functions of the CU may be implemented by one entity, or by different entities. For example, the functions of the CU may be further divided, that is, the control plane and the user plane may be separated and implemented by different entities, namely the control plane CU entity (i.e., CU-control plane (CP) entity) and the user plane CU entity (i.e., CU-user plane (UP) entity). The CU-CP entity and the CU-UP entity may be coupled with the DU to jointly perform the functions of the RAN node. The CU and DU may be set separately, or may be included in the same network element, such as the baseband unit (BBU).

[0072] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0073] The CU and DU can be configured according to the protocol layer functions of the wireless network they implement: for example, the CU is configured to implement the functions of the packet data convergence protocol (PDCP) layer and the protocol layers above it (such as the radio resource control (RRC) layer and / or the service data adaptation protocol (SDAP) layer, etc.); the DU is configured to implement the functions of the protocol layers below the PDCP layer (such as the radio link control (RLC), the media access control (MAC) layer, and / or the physical (PHY) layer, etc.). For another example, the CU is configured to implement the functions of the protocol layers above the PDCP layer (such as the RRC layer and / or the SDAP layer), and the DU is configured to implement the functions of the PDCP layer and the protocol layers below it (such as the RLC layer, the MAC layer, and / or the PHY layer, etc.). For a detailed description of the above-mentioned protocol layers, please refer to the relevant technical specifications of 3GPP or the technical specifications of other applicable communication protocols. The above division of the processing functions of the CU and DU according to the protocol layer is only an example, and can also be divided in other ways, which is not limited by this application. For example, in one design, the CU or DU can also be divided into parts with partial processing functions of the protocol layer. In one design, part of the RLC layer functions and the functions of the protocol layers above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are set in the DU.

[0074] In the embodiments of the present application, the device for implementing the functions of the network device can be the network device itself, or a device that can support the network device to implement the functions, such as a chip system or a combination of devices or components that can implement the functions of the network device, and the device can be installed in the network device. The embodiments of the present application do not limit the specific technology and specific device form used by the network device.

[0075] Terminal devices are also referred to as terminals, terminal devices, user equipment (UE), mobile stations, or mobile terminals. In the embodiments of the present application, anything that can communicate data with a base station can be considered a terminal device. Terminal devices can be widely used in various scenarios. For example, terminal devices can be: mobile phones, computers, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, stations (STAs), robotic arms, cameras, robots, vehicles, drones, helicopters, airplanes, ships, or smart home devices (such as TVs, air conditioners, sweepers, speakers, set-top boxes), relays, customer premise equipment (CPEs), smart cars (smart cars or intelligent cars), roadside units (RSUs), etc. Terminal devices can also be terminal devices in IoT systems, such as water meters, electricity meters, etc.

[0076] The various terminal devices introduced above, if located on a vehicle (for example, placed / installed in a vehicle), can be considered as vehicle-mounted terminal devices. The vehicle-mounted terminal device can be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units, and the vehicle can implement the method of the present application through the built-in on-board module, on-board module, on-board component, on-board chip or on-board unit. The on-board terminal device can be a complete vehicle device, an on-board module, a vehicle, an on-board unit (OBU), a roadside unit (RSU), a vehicle-mounted system (or a vehicle-mounted sending unit) (telematics box, T-box), a chip or a system on chip (SOC), etc. The above chip or SOC can be installed in a vehicle, OBU, RSU or T-box.

[0077] In the embodiments of the present application, the device for implementing the functions of the terminal device can be the terminal device itself, or a device capable of supporting the terminal device in implementing the functions, such as a chip system or a combination of devices or components capable of implementing the functions of the terminal device, which can be installed in the terminal device. The embodiments of the present application do not limit the specific technology and specific device form used by the terminal device.

[0078] In an embodiment of the present application, the network device can be deployed on a satellite. When the network device is deployed on the satellite, a typical communication scenario is shown in Figure 2. The communication system shown in Figure 2 includes two terminal devices (which can be referred to as terminals), two base stations, a ground station and a core network device. The core network device includes a control plane function and a user plane function. For example, the control plane function includes an access and mobility management function (AMF) and a session management function (SMF). The user plane function includes: a user plane function (UPF), which is responsible for managing the transmission of user plane data, traffic statistics and other functions. (Including control plane functions and user plane functions). Among them, the base station is deployed on the satellite, also known as a satellite base station or a satellite-borne base station (satellite gNB, S-gNB). The air interface refers to the communication interface between the terminal device and the base station. The Xn interface refers to the interface between the base station and the base station, which is mainly used for signaling interaction such as switching. The NG interface refers to the interface between the base station and the core network, or the interface between the ground station and the core network, which mainly interacts with the core network's non-access stratum (NAS) and other signaling, as well as user service data. The NG interface can be either wired or wireless. In Figure 2, the satellite base station communicates with the ground station via the air interface, and the ground station is connected to the core network via the NG interface. The terminal equipment on the ground communicates with the satellite base station via the air interface, thereby accessing the communication network. The embodiment of the present application does not limit the type and number of satellites. For example, the satellite can be a highly elliptical orbiting (HEO) satellite, a geostationary earth orbit (GEO) satellite, a medium earth orbit (MEO) satellite, and a low-earth orbit (LEO) satellite.

[0079] Considering the coverage and capacity distribution of communication systems, satellites are typically deployed at various orbital altitudes and with varying inclination angles. This type of communication system is also known as a multi-layer satellite network or multi-layer constellation network. Satellites at the same orbital altitude can be considered a layer. A constellation is a collection of satellites launched into orbit and functioning normally, also known as a satellite constellation. Satellites can notify terminal devices of their presence through beam scanning. Beam scanning is the process of transmitting a satellite signal (SSB). The satellite transmits an SSB, which is received by terminals within the satellite's coverage area, allowing the terminal device to connect to the satellite and access the network.

[0080] In a multi-layer satellite network, each layer of satellites is relatively independent and moves at high speeds. If each satellite transmits SSB independently, multiple satellites' SSBs may correspond to the same geographic area, or the geographical areas corresponding to multiple satellites' SSBs may overlap significantly. For terminal devices, the received SSBs may be subject to significant interference, making it difficult to demodulate the SSBs corresponding to each satellite from the received signal.

[0081] In order to solve the above problems, the solution of the embodiment of the present application is proposed. In the embodiment of the present application, the anchor satellite of the terminal device plans the way in which each satellite within the coverage of the anchor satellite sends SSB, so as to reduce or even avoid the interference of SSB between each satellite. In comparison, the satellite within the coverage of the anchor satellite can be called a sub-satellite or a slave satellite. The coverage of the anchor satellite is larger than the coverage of the sub-satellite, and the movement speed of the anchor satellite is faster than the movement speed of the sub-satellite. The terminal device within the coverage (or coverage area) of the anchor satellite can access any sub-satellite within the coverage of the anchor satellite. The anchor satellite knows the location of the terminal device, and thus knows the sub-satellite that the terminal device may access.

[0082] For example, please refer to Figure 3, which is another architectural diagram of a communication system applicable to an embodiment of the present application. The system shown in Figure 3 includes an anchor satellite and multiple sub-satellites (such as sub-satellite 1 to sub-satellite 4 in Figure 3) and a terminal device. Among them, sub-satellite 1 to sub-satellite 4 are all within the coverage range of the anchor satellite. The coverage ranges of each sub-satellite may overlap or not overlap. For example, sub-satellite 1 corresponds to coverage range A, sub-satellite 2 corresponds to coverage range B, sub-satellite 3 corresponds to coverage range C, and sub-satellite 4 corresponds to coverage range D. The anchor satellite can plan how sub-satellite 1 to sub-satellite 4 send SSBs, or the anchor satellite can instruct sub-satellite 1 to sub-satellite 4 how to send SSBs. In this way, the SSBs sent by sub-satellite 1 to sub-satellite 4 do not interfere with each other, so that the terminal device can clearly know which sub-satellite the received SSB belongs to, and then access the network.

[0083] In the embodiments of the present application, the word "association" can be replaced with "mapping," "correlation," or "correspondence." For example, the association between at least one synchronization index and at least one piece of ephemeris information can also be a correspondence between at least one synchronization index and at least one piece of ephemeris information. The ephemeris information associated with a synchronization index can be the ephemeris information corresponding to the synchronization index. The embodiments of the present application do not limit the specific implementation of the association. For example, the association can be a table, and sending the first association can be sending a table representing the first association.

[0084] In the embodiments of the present application, beam can be understood as / replaced with "spatial filter," "spatial parameters," "outer weight," "simulated weight," or "simulated beam." Random access preamble is also referred to as preamble, preamble, preamble code, random access preamble, etc. Preconfiguration, equivalent to (pre)configuration, can refer to predefinition or signaling configuration / indication between intersatellite links.

[0085] "When...", "if..." and "if" all mean that the device will make corresponding processing under certain objective circumstances. It does not limit the time, nor does it require that the device must have a judgment action when it is implemented, nor does it mean that there are other limitations. Unless otherwise specified, "if" and "if" are interchangeable, and "when..." and "in the case of..." are interchangeable. "When..." and "if" / "if" are interchangeable. Words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific way. "For indication" can include direct indication and indirect indication. For example, when describing that a certain indication information is used to indicate information I, it can include that the indication information directly indicates I or indirectly indicates I, and it does not mean that the indication information must carry I.

[0086] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0087] The ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. For example, the first satellite and the second satellite refer to two different satellites, and do not indicate the difference in priority or importance of the two satellites. For a technical feature, "A", "B", "C" and "D" are used to distinguish the technical features in the technical feature. There is no order of precedence or order of importance between the technical features described by "A", "B", "C" and "D". For example, the second satellite A and the second satellite B in this article are only used to distinguish different contents, and do not limit the order of precedence or order of priority or importance between the second satellite A and the second satellite B.

[0088] The solution provided by the embodiment of the present application is described in detail below with reference to the accompanying drawings. In the following introduction, the communication method provided by the embodiment of the present application is applied to the network architecture shown in Figure 1, Figure 2 or Figure 3 as an example. The network architecture and application scenarios described in the embodiment of the present application are for the purpose of more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation on the technical solution provided by the embodiment of the present application. It is known to those skilled in the art that with the evolution of the network architecture and the emergence of new application scenarios, the technical solution provided by the embodiment of the present application is also applicable to similar technical problems.

[0089] The following takes the communication method (such as communication method 400, communication method 600 and communication method 800) provided in the embodiment of the present application as an example performed by a first satellite, a second satellite and a terminal device. The steps performed by the satellite can be implemented by the satellite itself, or by components in the satellite (such as baseband chips, or other processing units or processor modules). For example, the first satellite can be the anchor satellite in Figure 3, or it can be the chip (system) in the anchor satellite in Figure 3. The second satellite can be any sub-satellite in Figure 3, or it can be implemented by the chip (system) in the sub-satellite in Figure 3. The steps performed by the terminal device can be implemented by the terminal device itself, or it can be implemented by components in the terminal device (such as chips, processing units, or processor modules). The terminal device can be the terminal device shown in Figure 3, or it can be the chip (system) in the terminal device in Figure 3.

[0090] Please refer to Figure 4, which is a flow chart of the communication method 400 provided in an embodiment of the present application. Figure 4 introduces the method from the perspective of the interaction between the first satellite, the second satellite and the terminal device. It should be understood that the communication method 400 can also be implemented by other devices, such as a chip or communication device with communication functions. It should be noted that the embodiment of the present application only takes the execution through the first satellite, the second satellite and the terminal device as an example, and is not limited to the number of second satellites and terminal devices. For example, the embodiment of the present application can also be executed by more second satellites and more terminal devices. When more second satellites are involved, the execution process of each second satellite in these multiple second satellites is the same. As shown in Figure 4, the process of the communication method 400 includes the following steps. The communication method 400 is essentially planning how multiple second satellites send synchronization signals, and accordingly, the synchronization index is the index of the synchronization signal. For the convenience of description, the following takes the synchronization signal being SSB as an example, and accordingly, the synchronization index is the index of SSB.

[0091] S401: A first satellite sends first information, where the first information includes synchronization information of at least one second satellite.

[0092] The first satellite is the anchor satellite for the terminal device, and the second satellite is a sub-satellite within the coverage area of ​​the first satellite. Continuing with the example in Figure 3 , the at least one second satellite is sub-satellite 1 through sub-satellite 4. The synchronization information of each second satellite can be used to synchronize the terminal device with the second satellite, including time and frequency synchronization. The embodiments of the present application do not limit the specific name of the synchronization information; for example, the synchronization information can be referred to as a synchronization signal or SSB.

[0093] The synchronization information of each second satellite may include at least one synchronization index (also referred to as an index), which may indicate the synchronization signal to be transmitted by the corresponding second satellite. Continuing with the example of FIG3 , taking sub-satellite 1 as an example, the synchronization signal of sub-satellite 1 includes at least one synchronization index, which is the index of the SSB transmitted by sub-satellite 1. The number of synchronization indexes included in the synchronization information of different second satellites may be the same or different, and different second satellites may have different synchronization indexes. The first satellite may plan the SSBs to be transmitted for each second satellite so that interference between the SSBs transmitted by each second satellite is minimal or even eliminated. For example, the synchronization information corresponding to sub-satellite 1 includes SSB indexes 0 to 3, the synchronization information corresponding to sub-satellite 2 includes SSB indexes 4 to 8, and so on. In this way, compared to each second satellite independently transmitting SSBs according to its own plan, interference between SSBs transmitted by multiple second satellites can be reduced or even avoided.

[0094] Optionally, at least one synchronization index may be present in a table form. In this case, the first information may include at least one list, one list corresponding to one second satellite, and one list including at least one synchronization index. Alternatively, the first information may include an index of at least one list, and the terminal device may store multiple lists and the indexes corresponding to each list. In this way, when each satellite receives the first information, it can determine the corresponding list based on the index carried by the first information, and then determine the at least one synchronization index included in the list. Alternatively, the terminal device may store a table indicating multiple groups of synchronization indexes, each group of synchronization indexes having a corresponding index, a group of synchronization indexes corresponding to one second satellite, and including at least one synchronization index, as shown in Table 1. Accordingly, the first information may include the index of at least one group of synchronization indexes corresponding to at least one second satellite in the multiple groups of synchronization indexes.

[0095] Table 1

[0096] It should be noted that the number of synchronization indexes in each synchronization index group in Table 1 is for example only. The number of synchronization indexes in different synchronization index groups can be the same or different. The number of synchronization index groups in Table 1 is also for example only. There can be more synchronization index groups. One or more synchronization indexes in different synchronization index groups can be different.

[0097] In addition, the synchronization information of each second satellite may further include time information corresponding to at least one synchronization index. This time information may be used to indicate the time when at least one second satellite transmits a synchronization signal. The time information corresponding to the at least one synchronization index may be the same or different. The times indicated by the time information included in the synchronization information of different second satellites may be the same or different. For example, the first information includes synchronization information A of second satellite A. This synchronization information A includes at least one synchronization index and at least one time information, where the at least one time information corresponds to the at least one synchronization index. For example, the at least one time information may be a time information indicating that second satellite A transmits the at least one SSB corresponding to the synchronization index at the time indicated by the time information. Alternatively, the at least one time information may correspond one-to-one with the at least one synchronization index, with each time information indicating that the second satellite transmits the SSB indicated by the synchronization index corresponding to the time information at the time indicated by the time information. For another example, the first information includes synchronization information A of second satellite A and synchronization information B of second satellite B. This synchronization information A includes at least one synchronization index and at least one time information, and synchronization information B includes at least one synchronization index and at least one time information. One time information in synchronization information A corresponds to at least one synchronization index, and at least one time information in synchronization information B corresponds to at least one synchronization index. The at least one time information in synchronization information A and the at least one time information in synchronization information B may be the same or different. The time information and synchronization index carried by the synchronization information of each second satellite may be determined by the first satellite. In this way, different second satellites may transmit different SSBs, thereby reducing and avoiding SSB interference between multiple second satellites. Alternatively, different second satellites may transmit different SSBs at the same time, or different second satellites may transmit the same SSB at different times. This reduces SSB interference between multiple second satellites while conserving SSB resources and ensuring coverage as much as possible.

[0098] In a possible implementation, the first satellite may transmit the first information in a unicast manner. Each transmission of the first information includes synchronization information of a second satellite. For example, for a second satellite A, the first satellite transmits the first information to the second satellite A. The first information includes synchronization information of the second satellite A. For a second satellite B, the first satellite transmits the first information to the second satellite B. The first information includes synchronization information of the second satellite A. Unicast transmission of the first information by the first satellite reduces the complexity of the second satellite's processing of the first information.

[0099] Alternatively, the first satellite can broadcast the first information to save signaling overhead. In this case, each second satellite receives the first information and needs to determine which synchronization information in the at least one synchronization information carried by the first information is its own. To this end, the first information can also include ephemeris information of at least one second satellite. That is, the first information includes at least one synchronization information and identification information of at least one second satellite, where one synchronization information can correspond to the identification information of one or more second satellites. Each second satellite receives the first information and can determine its own synchronization information based on the identification information of at least one second satellite and the correspondence between the identification information of at least one second satellite and the at least one synchronization information.

[0100] The embodiments of the present application do not limit the specific implementation of the identification information of the at least one second satellite. For example, the identification information of the at least one second satellite is the ephemeris information of the at least one second satellite. In another example, the identification information of the at least one second satellite is the ID of the at least one second satellite. In another example, the identification information of the at least one second satellite is the ID of at least one TRP, where one TRP corresponds to one second satellite.

[0101] S402: The second satellite sends a first synchronization signal. Correspondingly, a terminal device within the coverage of the second satellite receives the first synchronization signal.

[0102] The second satellite in S402 refers to any one of the at least one second satellites. For ease of description, the following uses second satellite A as an example. Upon receiving the first message, second satellite A may obtain synchronization information corresponding to second satellite A and transmit a first synchronization signal based on the synchronization information. If the first message is transmitted in unicast mode, second satellite A determines that the synchronization information carried in the first message is the synchronization information of second satellite A. If the first message is transmitted in broadcast mode, upon receiving the first message, second satellite A may determine the synchronization information of second satellite A based on the identification information of the at least one second satellite in the first message and the correspondence between the identification information of the at least one second satellite and the at least one synchronization information.

[0103] Second satellite A transmits a synchronization signal based on the synchronization information of second satellite A. For example, the synchronization information of second satellite A includes at least one synchronization index including a second synchronization index, and the first synchronization signal includes the second synchronization index and the ephemeris information corresponding to the second synchronization index (e.g., the second ephemeris information herein). Taking the first synchronization signal as a first SSB as an example, if the at least one synchronization index includes multiple synchronization indexes, then the first SSB transmitted by second satellite A includes the multiple synchronization indexes and multiple ephemeris information, with one synchronization index corresponding to one ephemeris information. Alternatively, if the at least one synchronization index includes multiple synchronization indexes, second satellite A transmits multiple SSBs corresponding one-to-one to the multiple synchronization indexes, each SSB including a corresponding synchronization index and the ephemeris information corresponding to the synchronization index. The ephemeris information corresponding to the synchronization indexes corresponding to different second satellites is different. Taking second satellite A and another second satellite (e.g., second satellite B) as an example, the synchronization information of second satellite A includes a second synchronization index, which corresponds to the second ephemeris information, and the synchronization information of second satellite B includes a third synchronization index, which corresponds to the third ephemeris information, wherein the second satellite information and the third ephemeris information are different. The ephemeris information corresponding to the synchronization index may be carried in the first field of the system information block (SIB) included in the SSB. The first field may be an existing field in the SIB or a newly added field.

[0104] Optionally, the second ephemeris information carried in the first SSB transmitted by the second satellite A can be represented by the ID of the second satellite A or the ID of the TRP indicating the second satellite A. Therefore, the first SSB including the second synchronization index and the second ephemeris information can be replaced by: the first SSB including the second synchronization index and the ID of the second satellite A, or the first SSB including the second synchronization index and the ID of the second TRP, where the second TRP indicates the second satellite A. When the first BSS includes the second synchronization index and the ID of the second satellite A, the first or second satellite A can also broadcast the correspondence between the ID of at least one second satellite and the at least one piece of ephemeris information to the terminal device. In this way, the terminal device can determine the second ephemeris information corresponding to the second synchronization index based on the correspondence between the ID of the at least one second satellite and the at least one piece of ephemeris information and the received first SSB. Similarly, when the first BSS includes the second synchronization index and the ID of the second TRP, the first or second satellite A can also broadcast the correspondence between the ID of at least one TRP and the at least one piece of ephemeris information to the terminal device.

[0105] In a possible implementation, the first SSB sent by the second satellite A may include a second synchronization index and an association relationship between at least one synchronization index and at least one ephemeris information, and the association relationship is referred to as a first association relationship. Alternatively, the first SSB includes the second synchronization index and the second ephemeris information includes: the first SSB includes the second synchronization index and the first association relationship. The first association relationship may be carried in a field in the SIB included in the first SSB. The first association relationship may also be broadcast by the first satellite. The first association relationship may exist in a tabular form, as shown in Table 2. In the first association relationship, one ephemeris information may correspond to one or more synchronization indexes. It should be noted that the relationship between the synchronization index and the ephemeris information in Table 2 is only an example, and the value of N in Table 2 is greater than or equal to 2.

[0106] Table 2

[0107] S403: The terminal device determines second ephemeris information according to the first synchronization signal, and sends a random access preamble according to the second ephemeris information.

[0108] After receiving the first synchronization signal, the terminal device determines the second ephemeris information based on the first synchronization signal. For example, if the first synchronization signal includes a second synchronization index and second ephemeris information, the terminal device may directly obtain the second ephemeris information from the first synchronization signal. If the first synchronization signal includes the second synchronization index and the first association, the terminal device may determine the second ephemeris information corresponding to the second synchronization index based on the second synchronization index and the first association. If the first synchronization signal includes the second synchronization index and the ID of a second satellite A, the terminal device may determine the second ephemeris information based on the correspondence between the ID of at least one second satellite and the at least one ephemeris information and the ID of the second satellite A.

[0109] After determining the second ephemeris information, the terminal device determines a TA amount based on the second ephemeris information, and then sends a random access preamble based on the determined TA amount to access the second satellite A. It will be understood that if the terminal device is located within the coverage of the second satellite B, the terminal device can receive a synchronization signal from the second satellite B, and determine the ephemeris information of the second satellite B based on the received synchronization signal to calculate the TA amount, and send a random access preamble based on the TA amount to access the second satellite B.

[0110] When the synchronization information of the second satellite A includes at least one synchronization index and time information corresponding to the at least one synchronization index, the second satellite A transmits the first synchronization signal according to the time information included in the synchronization information. For example, if the synchronization information of the second satellite A includes a second synchronization index and time information corresponding to the second synchronization index, the second satellite A transmits the first synchronization signal at the time indicated by the time information, and the first synchronization signal includes the second synchronization index.

[0111] Due to the movement of the second satellite, the terminal device moves from the coverage of one second satellite to the coverage of another second satellite. For example, in the initial stage, the terminal device is located in the coverage of the second satellite A. After a period of time, the terminal device moves to the coverage of the second satellite C, which requires the terminal device to switch from the second satellite A to the second satellite C. In order to reduce the interruption of communication services, the terminal device needs to switch from the cell of the second satellite A to the cell of the second satellite C, which affects the data transmission performance of the terminal device. To this end, in an embodiment of the present application, the cell identifiers of multiple second satellites are the same. In this way, when the terminal device moves from the coverage of one second satellite to the coverage of another second satellite, it is considered that the cell has not changed, so that the cell switching process will not be executed, reducing the impact on the data transmission performance of the terminal device. The embodiment of the present application does not limit the specific implementation form of the cell identifier of the second satellite. For example, the cell identifier can be a physical cell identifier (PCI).

[0112] In communication method 400, the first satellite plans the SSBs transmitted by each second satellite so that different second satellites transmit different SSBs, thereby reducing SSB interference between multiple second satellites. For example, different second satellites may transmit different SSBs at the same time, thereby reducing SSB interference between multiple second satellites and conserving SSB resources. For another example, different second satellites may transmit the same SSB at different times to minimize or even eliminate SSB interference between multiple second satellites.

[0113] It should be noted that, in the communication method 400, the SSB to be sent by each second satellite may also be pre-configured. Therefore, S401 is not a step that must be performed and is indicated by a dotted line in FIG4 .

[0114] In a possible scenario, the orbital altitude of the first satellite is higher than the orbital altitude of the second satellite, then the speed of the first satellite relative to the ground is lower than the speed of the second satellite relative to the ground. As the first satellite and the second satellite move, there will be a situation where the second satellite cannot provide services for the terminal device. For example, please refer to Figure 5, which is a schematic diagram of the staring service during the satellite movement process provided in an embodiment of the present application. "Staring" refers to a working mode of a payload (such as a beam) in a satellite communication system. In staring mode, the satellite dynamically adjusts its own beam pointing through technologies such as satellite air attitude adjustment and phased array parameter adjustment, so that the beam approximately covers the same area on the ground. As shown in Figure 5, the staring service area of ​​the anchor satellite (i.e., the first satellite in this article) in the initial stage is the area indicated by the dotted line in the figure. After the anchor satellite and each sub-satellite (i.e., the second satellite) move for a period of time, the staring service area of ​​the anchor satellite is the area indicated by the solid line in the figure. For the terminal device, the second satellite that could originally provide services for the terminal device may no longer be able to provide services for the terminal device. As shown in FIG5 , the terminal device is in the coverage area A of the sub-satellite 1. As the sub-satellite 1 moves, the terminal device is no longer in the coverage area of ​​the sub-satellite 1. At this time, the sub-satellite 1 can no longer provide services for the terminal device.

[0115] Regarding the situation shown in Figure 5, an embodiment of the present application further provides a communication method. In this communication method, when a sub-satellite cannot provide service to a terminal device, the anchor satellite decides to use another sub-satellite to replace the unavailable sub-satellite to continue providing service to the terminal device, thereby reducing the impact on the terminal device's data transmission performance. Please refer to Figure 6 for a flow diagram of a communication method 600 provided in an embodiment of the present application. Figure 6 describes the method from the perspective of the interaction between a first satellite, a second satellite A, a second satellite B, and a terminal device. It should be understood that communication method 600 can also be implemented by other devices, such as a chip or communication device equipped with communication capabilities.

[0116] S601: The second satellite B sends third information to the first satellite. Correspondingly, the first satellite receives the third information from the second satellite B.

[0117] The second satellite B cannot provide services to the terminal device. The second satellite B cannot provide services to the terminal device, including the second satellite B being unable to provide services to the terminal device at one or more times. Alternatively, the second satellite B cannot provide services to the terminal device, including the second satellite B being unable to provide services for one or more synchronization indices, that is, the second satellite B cannot transmit synchronization signals including one or more synchronization indices. Alternatively, the second satellite B cannot provide services to the terminal device, including the second satellite B being unable to provide services for one or more synchronization indices at one or more times. For ease of description, the following description will refer to the second satellite B being unable to transmit synchronization signals including the first synchronization index at the time indicated by the first time information. The first time information may indicate one or more times, and these one or more times are not the times when the second satellite B provides services based on the first synchronization index. The first synchronization index may indicate one or more synchronization indices.

[0118] Due to reasons such as antenna scanning range, the second satellite B cannot provide service at the wavelength of the first synchronization index. A wavelength can be understood as an area within the coverage range of the second satellite B. The wavelength of the first synchronization index can be understood as the area covered by the synchronization signal indicated by the first synchronization index. When the second satellite B determines that the first synchronization index cannot provide service at the time indicated by the first time information, it can notify the first satellite. For example, the second satellite B sends third information to the first satellite. The third information is used to indicate the time and synchronization index at which the second satellite B cannot provide service. For example, the third information includes the first time information and the first synchronization index. The first time information and the first synchronization index can both be in table form. Accordingly, the third information can include a first list and a second list. The first list includes the time indicated by the first time information, and the second list includes the first synchronization index.

[0119] If the first satellite can know the time and synchronization index when each second satellite in the coverage area cannot provide service, then S601 does not need to be executed. In other words, S601 is not a must-do step and is indicated by a dotted line in FIG6 .

[0120] S602: The first satellite sends second information to the second satellite A. Correspondingly, the second satellite A receives the second information from the first satellite.

[0121] The second satellite A is a satellite that can replace the second satellite B in providing services to the terminal device. The first satellite receives third information from the second satellite B and determines that the second satellite B cannot provide services to the terminal device based on the first synchronization index at the time indicated by the first time information. The first satellite determines a satellite (e.g., the second satellite A) that can replace the second satellite B in providing services to the terminal device. The second satellite A can provide services to the terminal device based on the first synchronization index according to the first time information. After determining the second satellite A, the first satellite instructs the second satellite A to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information. For example, the first satellite sends second information to the second satellite A, where the second information includes the first time information and the first synchronization index, and is used to instruct the second satellite A to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information.

[0122] S603: The second satellite A sends a second synchronization signal, where the second synchronization signal includes the first synchronization index.

[0123] Second satellite A receives the second information from the first satellite and transmits a synchronization signal based on the second information. For example, second satellite A transmits a second synchronization signal at the time indicated by the first time information. The second synchronization signal includes a first synchronization index. Optionally, the second synchronization signal also includes first ephemeris information corresponding to the first synchronization index, that is, the second synchronization signal includes the first synchronization index and the first ephemeris information. In this manner, a terminal device receives the second synchronization signal, determines a TA amount based on the first ephemeris information, and then transmits a random access preamble based on the TA amount to access the network. The specific implementation of the second synchronization signal including the first synchronization index and the first ephemeris information can refer to the specific implementation of the first synchronization signal including the second synchronization index and the second ephemeris information described above. For example, the second synchronization signal includes the first synchronization index and also includes a SIB, which carries an association between at least one synchronization index and at least one ephemeris information. This description is omitted here. When second satellite A transmits the second synchronization signal, it may update the already stored first association, where the first synchronization index in the updated first association corresponds to the first ephemeris information.

[0124] Similar to the second satellite B, when the second satellite A cannot provide service using a certain synchronization index at a certain time or times, the second satellite A may notify the first satellite. For example, the second satellite A may send fourth information to the first satellite, indicating the time and synchronization index at which the second satellite A cannot provide service. For example, the fourth information includes the second time information and a third synchronization index, where the third synchronization index cannot provide service at the time indicated by the second time information. The second time information and the third synchronization index may both be in table form.

[0125] S604: The terminal device determines the first ephemeris information based on the second synchronization signal, and sends a random access preamble according to the first ephemeris information.

[0126] After receiving the second synchronization signal, the terminal device may obtain the first ephemeris information, determine the TA amount based on the first ephemeris information, and then send a random access preamble based on the determined TA amount to access the second satellite A. The specific implementation of the terminal device obtaining the first ephemeris information may refer to the specific implementation of the terminal device receiving the first synchronization signal and obtaining the second ephemeris information in S403 above, and will not be repeated here.

[0127] In communication method 600, when a sub-satellite cannot provide services for a terminal device, the anchor satellite decides to use another sub-satellite to replace the sub-satellite that cannot provide services to continue to provide services for the terminal device, which can reduce the impact on the data transmission performance of the terminal device.

[0128] Communication method 600 can be combined with communication method 400. For example, after S401 to S403 are executed, S601 to S603 can be executed. The order in which S401 to S403 and each of S601 to S603 are executed is not limited, and all steps do not necessarily need to be executed. For example, S602, S603, S604, S401, S402, and S403 can be executed in sequence.

[0129] In a possible scenario, a terminal device may not need to transmit data for a period of time. If the satellite continues to send synchronization signals during this period, it is unnecessary for the terminal device, resulting in a waste of resources and additional power consumption of the satellite. To this end, an embodiment of the present application also provides a communication method in which the anchor satellite schedules appropriate sub-satellites to transmit synchronization signals based on the actual needs of the terminal device, thereby reducing the transmission of unnecessary synchronization signals, thereby saving resources and reducing satellite power consumption.

[0130] In this method, random access resources of a first satellite may be (pre-)configured. For ease of description, the set of random access resources of the first satellite is referred to as a first resource set. The first resource set may be divided into multiple sub-resource sets, each sub-resource set corresponding to a second satellite, and a second satellite may correspond to one or more sub-resource sets. In this manner, the first satellite can determine which second satellite is within the coverage area of ​​the terminal device based on the resources used in the random access preamble received from the terminal device, thereby scheduling the second satellite to provide service to the terminal device.

[0131] For ease of understanding, please refer to Figure 7, which is a schematic diagram of the architecture of a satellite communication system provided in an embodiment of the present application. In Figure 7, the projection of the beam of the anchor satellite on the ground is larger than the projection of the beams of multiple sub-satellites on the ground, or the beam position of the anchor satellite nests the beam positions of each sub-satellite. In Figure 7, take beam position A as a beam position of the anchor satellite, and beam position a, beam position b, and beam position c as the beam positions of multiple sub-satellites under the anchor satellite as an example. Wave position a, wave position b, and wave position c are nested in wave position A. One wave position can correspond to one random access resource set. For example, wave position A corresponds to one random access resource set, and beams a, beam position b, and beam position c each correspond to one random access resource set. The random access resource sets corresponding to beams a, beam position b, and beam position c are nested in the random access resource set corresponding to wave position A. For example, the random access resource set corresponding to waveband A is called random access resource set A, the random access resource set corresponding to waveband a is called random access resource set a, the random access resource set corresponding to waveband b is called random access resource set b, and the random access resource set corresponding to waveband c is called random access resource set c. Random access resource set a, random access resource set b, and random access resource set c are subsets of random access resource set A, and random access resource set a, random access resource set b, and random access resource set c do not overlap. If the random access resource set used by a terminal device corresponds to the waveband of a sub-satellite, the anchor satellite can determine that the sub-satellite can provide services for the terminal device.

[0132] Accordingly, please refer to Figure 8, which is a flowchart illustrating a communication method 800 according to an embodiment of the present application. Figure 8 describes the method from the perspective of interaction between a first satellite, a second satellite A, and a terminal device. It should be understood that communication method 800 can also be implemented by other devices, such as a chip or communication device with communication capabilities.

[0133] S801. A first satellite sends fifth information to a terminal device. Correspondingly, the terminal device receives the fifth information from the first satellite.

[0134] The fifth information is used to indicate a second association relationship, which includes an association relationship between multiple sub-resource sets and the first resource set. The first resource set can be a set of random access resources of the first satellite, or a set of random access resources corresponding to a certain waveband of the first satellite. The multiple sub-resource sets can be multiple sub-resource sets obtained by dividing the first resource set, or partial sub-resource sets after the first resource set is divided. One sub-resource set corresponds to one second satellite, and one second satellite can correspond to multiple sub-resource sets, as shown in Table 3. In Table 3, the first resource set can be a set of random access resources of the first satellite, or a set of random access resources corresponding to a certain waveband of the first satellite. The second association relationship can be the association relationship shown in Table 3, or the association relationships shown in the first two columns of Table 3.

[0135] Table 3

[0136] Taking the first resource set in Table 3 as the random access resource set corresponding to beam position A of the first satellite as an example, beam position A nests beam position a, beam position b, and beam position c. The first sub-resource set is the random access resource set of beam position a nested within beam position A, the second sub-resource set is the random access resource set of beam position b nested within beam position A, and the third sub-resource set is the random access resource set of beam position c nested within beam position A. Beam position a corresponds to the second satellite A, beam b corresponds to the second satellite A, and beam position c corresponds to the second satellite B. The first sub-resource set, the second sub-resource set, and the third sub-resource set are subsets of the first resource set, and the first sub-resource set, the second sub-resource set, and the third sub-resource set do not overlap with each other. Non-overlapping resource sets here means that the resources within the set differ in at least one of the three dimensions: time domain, frequency domain, or code domain. Taking the first sub-resource set and the second sub-resource set as an example, the resources in the first sub-resource set and the resources in the second sub-resource set are the same in the time domain and the frequency domain, but the corresponding sequences are different; or, the resources in the first sub-resource set and the resources in the second sub-resource set are the same in the time domain, and the corresponding sequences are the same, but different in the frequency domain; or, the resources in the first sub-resource set and the resources in the second sub-resource set have the same corresponding sequences and are the same in the frequency domain, but different in the time domain; or, the resources in the first sub-resource set and the resources in the second sub-resource set are different in the time domain and the frequency domain, but the corresponding sequences are the same or different, and so on.

[0137] The second association relationship may be preconfigured, and the terminal device and the first satellite may store the second association relationship shown in Table 3. In this case, S801 need not be executed; that is, S801 is an optional step, illustrated by a dashed line in Figure 8. Alternatively, the second association relationship may be sent by the first satellite to the terminal device. For example, the first satellite may send a synchronization signal to the terminal device, where the synchronization signal includes information indicating the second association relationship. For example, if the synchronization signal is an SSB, the indication information may be carried in a SIB.

[0138] S802. The first satellite sends a third synchronization signal, and accordingly, the terminal device receives the third synchronization signal.

[0139] The first satellite transmitting the third synchronization signal includes the first satellite broadcasting the third synchronization signal, and the first satellite may use resources within the first resource set to transmit the third synchronization signal. Thus, upon receiving the third synchronization signal, the terminal device may determine, based on the third synchronization signal, that the resources used to transmit the third synchronization signal are from the first resource set.

[0140] S803: The terminal device sends a first random access preamble. Correspondingly, the first satellite receives the first random access preamble from the terminal device.

[0141] When a terminal device needs to transmit data, it can request network access. For example, the terminal device can send a first random access preamble. The first satellite receives the first random access preamble from the terminal device and determines that the terminal device needs to transmit data. In this case, the first satellite can determine which second satellite to schedule to serve the terminal device, eliminating the need to schedule all second satellites to transmit synchronization signals. This saves resources and reduces power consumption of other second satellites.

[0142] The terminal device may send a first random access preamble based on the second association. For example, based on the relationship shown in Table 3, the terminal device may randomly select a resource from the sub-resource set corresponding to the wavelength of the terminal device to send the first random access preamble. For example, if the terminal device is located in a wavelength covered by the second satellite A, the terminal device may randomly select a resource from the first sub-resource set or the second sub-resource set to send the first random access preamble.

[0143] S804: The first satellite determines the second satellite A according to the first random access preamble and the second association relationship.

[0144] Second satellite A is a terminal device that provides service to the terminal device among multiple second satellites in the system. The second association relationship also includes association relationships between multiple sub-resource sets and multiple second satellites, as shown in Table 3. As can be seen from Table 3, each sub-resource set has a corresponding second satellite. Therefore, the first satellite can determine the second satellite that can provide service to the terminal device based on the second association relationship shown in Table 3 and the random access preamble sent by the terminal device, thereby scheduling the second satellite. For example, if the terminal device sends a first random access preamble that belongs to the first sub-resource set, then the second satellite that can provide service to the terminal device is second satellite A.

[0145] After determining the second satellite A, the first satellite may schedule the second satellite A to transmit a synchronization signal. For example, the first satellite may transmit sixth information to the second satellite A. The sixth information may be used to transmit the synchronization signal to at least the second satellite A. For example, the sixth information may include information related to the synchronization signal transmitted by the second satellite A, such as information about the resources used by the second satellite A to transmit the synchronization signal. The second satellite A receives the sixth information and transmits the synchronization signal based on the sixth information.

[0146] S805. The first satellite sends a random access response message to the terminal device. Correspondingly, the terminal device receives the random access response message.

[0147] The random access response message includes the ephemeris information and resource information of the second satellite A. The resource information indicates the resources used by the second satellite A to transmit synchronization signals. The ephemeris information of the second satellite A can be information associated with the ephemeris information of the second satellite A, as long as the terminal device can determine the ephemeris information of the second satellite A. For example, the ephemeris information of the second satellite A includes the ID of the second satellite A, the ID of the TRP corresponding to the second satellite A, or the PCI of the cell under the second satellite A. The association between one or more of the above information and the ephemeris information of the second satellite A can be sent by the first satellite to the terminal device, or the first satellite and the terminal device can agree on this association.

[0148] The resource information may be replaced with information related to the transmission of synchronization signals by the second satellite A. Thus, the random access response message including the ephemeris information and resource information of the second satellite A may be replaced with the random response message including the ephemeris information of the second satellite A and seventh information, where the sixth information is information related to the transmission of synchronization signals by the second satellite A. For example, the seventh information includes resource information indicating the resources used by the second satellite A to transmit the synchronization signal. The resource information may include one or more of time domain resource information occupied by the synchronization signal, frequency domain resource information, the center frequency of the synchronization signal, or a time domain offset value and / or a frequency domain offset value of the synchronization signal of the second satellite A relative to the synchronization signal of the first satellite.

[0149] S806. The terminal device receives a synchronization signal from the second satellite A on the resource indicated by the resource information.

[0150] After receiving the random access response message, the terminal device can determine the resources used by the second satellite A to send the synchronization signal, that is, the resources indicated by the resource information, and thus receive the synchronization signal from the second satellite A on the resources indicated by the resource information to access the network.

[0151] In communication method 800, a first satellite can be tuned to a suitable second satellite to transmit synchronization signals based on the actual needs of a terminal device. When a terminal device does not need to transmit information, it does not need to schedule any second satellite within its coverage area, thereby conserving resources and reducing power consumption of the second satellite.

[0152] The communication method 800 can be combined with the communication method 400 and the communication method 600. For example, the communication method 800 can be combined with the communication method 400, the communication method 800 can be combined with the communication method 600, and the communication method 800 can be combined with the communication method 400 and the communication method 600.

[0153] In the embodiments provided in the present application above, the methods provided in the embodiments of the present application are introduced by taking satellites (such as the first satellite and / or the second satellite) and terminal devices as examples. In the present application, each embodiment can be implemented independently or in combination based on certain internal connections; in each embodiment, different implementation methods can be implemented in combination or independently. In order to implement the various functions in the methods provided in the embodiments of the present application above, the steps performed by the terminal device can be implemented by different functional entities that constitute the terminal device. The steps performed by the satellite can be implemented by different functional entities that constitute the satellite. In order to implement the various functions in the methods provided in the embodiments of the present application above, the terminal device and the satellite may include hardware structures and / or software modules, and implement the above functions in the form of hardware structures, software modules, or hardware structures plus software modules. Whether one of the above functions is executed in the form of hardware structures, software modules, or hardware structures plus software modules depends on the specific application and design constraints of the technical solution.

[0154] Based on the same inventive concept as the method embodiment, the present embodiment provides a communication device. The following describes the communication device used to implement the above method in the present embodiment in conjunction with the accompanying drawings. The above content can be used in subsequent embodiments, and repeated content will not be repeated.

[0155] Figure 9 is a schematic block diagram of a communication device 900 provided in an embodiment of the present application. The communication device 900 may be a terminal device or a satellite in the above-described embodiments. For example, the communication device 900 may be the terminal device in Figure 1 ; or, the communication device 900 may be a chip (system) in the terminal device; or, the communication device 900 may be a software module in the terminal device. The communication device 900 may implement the functions or steps implemented by the terminal device in each of the above-described method embodiments. For another example, the communication device 900 may be the satellite in Figure 1 ; or, the communication device 900 may be a chip (system) in the satellite; or, the communication device 900 may be a software module in the satellite. The communication device 900 may implement the functions or steps implemented by the first or second satellite in each of the above-described method embodiments. The communication device 900 may include a processing module 910 and a transceiver module 920. Optionally, it may also include a storage module, which may be used to store instructions (code or program) and / or data. The storage module may be, for example, a memory. The processing module 910 and the transceiver module 920 may be coupled to the storage module. For example, the processing module 910 can read instructions (code or program) and / or data in the storage module to implement the corresponding method. When the communication device 900 is a chip in a terminal device or a satellite, the storage module can be a storage module in the chip, such as a register, a cache, etc. For example, the storage module can also be a storage module located outside the chip in the terminal device or satellite, such as a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM), etc. The above-mentioned units can be set independently or partially or fully integrated.

[0156] The processing module 910 can be a processor or controller, for example, a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processing (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It can implement or execute the various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, for example, including a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The transceiver module 920 is a transceiver, an interface circuit, a bus, a pin or other possible communication interface for receiving signals from other devices. For example, when the device is implemented in the form of a chip, the transceiver module 920 is an interface circuit for the chip to receive signals from other chips or devices, or it is an interface circuit for the chip to send signals to other chips or devices.

[0157] In one implementation, communication device 900 can implement the corresponding behaviors and functions of the first satellite in the above-described method embodiments. Communication device 900 can be a satellite, a component (e.g., a chip or circuit) used in a satellite, a chip or chipset in a satellite, or a portion of a chip used to perform the functions of the related methods, or a software module capable of implementing the methods performed by the first satellite in the above-described methods (e.g., communication method 400 and / or communication method 600, or communication method 800), without limitation. For details, please refer to the relevant content of the above-described method embodiments and will not be repeated here.

[0158] For example, the processing module 910 may be configured to determine first information, where the first information includes synchronization information of at least one second satellite, and each synchronization information of the second satellite includes at least one synchronization index. The transceiver module 920 may be configured to send the first information.

[0159] As an optional implementation manner, the synchronization information of each second satellite further includes a time corresponding to at least one synchronization index.

[0160] As an optional implementation, the first information also includes ephemeris information of at least one second satellite, or identification information of at least one second satellite, or identification information of at least one TRP, where one TRP corresponds to one second satellite.

[0161] As an optional implementation manner, the at least one second satellite includes multiple second satellites, and the cell identifiers corresponding to the multiple second satellites are the same.

[0162] As an optional implementation, the transceiver module 920 is further configured to send second information to a second satellite A among the plurality of second satellites, where the second information includes the first time information and the first synchronization index, and is configured to instruct the second satellite A to transmit a synchronization signal indicated by the first synchronization index at a time indicated by the first time information. The time indicated by the first time information does not fall within a time at which a second satellite B among the plurality of second satellites provides a service based on the first synchronization index.

[0163] As an optional implementation, the transceiver module 920 is further configured to receive, by the first satellite, third information from the second satellite B, where the third information includes the first time information and the first synchronization index.

[0164] For another example, the transceiver module 920 is configured to transmit a third synchronization signal using resources within the first resource set and receive a first random access preamble from a terminal device. The processing module 910 is configured to determine a second satellite A based on the first random access preamble and a second association relationship, where the second association relationship includes an association relationship between multiple sub-resource sets and multiple second satellites. The resources of the first random access preamble belong to a first sub-resource set among multiple sub-resource sets, and the second satellite A belongs to multiple second satellites. The transceiver module 920 is further configured to transmit a random access response message to the terminal device. The random access response message includes ephemeris information and resource information of the second satellite A. The resource information indicates the resources used by the second satellite A to transmit the synchronization signal.

[0165] As an optional implementation method, the transceiver module 920 is also used to send fifth information, which indicates a second association relationship. The second association relationship also includes an association relationship between multiple sub-resource sets and the first resource set, wherein the multiple sub-resource sets are obtained by dividing the first resource set.

[0166] In one implementation, the communication device 900 can implement the corresponding behaviors and functions of the second satellite (e.g., second satellite A or second satellite B) in the above-described method embodiments. The communication device 900 can be a satellite, a component (e.g., a chip or circuit) used in a satellite, a chip or chipset in a satellite, or a portion of a chip used to perform the functions of the relevant method, or a software module capable of implementing the methods executed by the satellite in the above-described methods (e.g., communication method 400 and / or communication method 600, or communication method 800), without limitation. For details, please refer to the relevant content of the above-described method embodiments and will not be repeated here.

[0167] For example, the processing module 910 is configured to determine a first synchronization signal, the first synchronization signal including a second synchronization index, the second synchronization index being associated with second ephemeris information, and the second ephemeris information being different from ephemeris information associated with synchronization indexes corresponding to other second satellites.

[0168] The transceiver module 920 is configured to send a first synchronization signal.

[0169] As an optional implementation manner, the first synchronization signal further includes: second ephemeris information, or a first association relationship, where the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information.

[0170] As an optional implementation, the transceiver module 920 is further configured to: receive first information from a first satellite, where the first information includes synchronization information of at least one second satellite, and the synchronization information of each second satellite includes at least one synchronization index.

[0171] As an optional implementation manner, the synchronization information of each second satellite further includes a time corresponding to at least one synchronization index.

[0172] As an optional implementation, the first information also includes ephemeris information of at least one second satellite, or identification information of at least one second satellite, or identification information of at least one TRP, where one TRP corresponds to one second satellite.

[0173] As an optional implementation, the transceiver module 920 is further configured to receive second information from the first satellite and transmit a second synchronization signal at the time indicated by the first time information, where the second synchronization signal includes a first synchronization index. The second information includes the first time information and the first synchronization index, and is configured to instruct the second satellite to transmit a synchronization signal indicated by the first synchronization index at the time indicated by the first time information. The time indicated by the first time information does not correspond to a time at which another second satellite provides services based on the first synchronization index.

[0174] As an optional implementation, the transceiver module 920 is further configured to send fourth information to the first satellite, where the fourth information includes the second time information and a third synchronization index, and the third synchronization index cannot provide service at the time indicated by the second time information.

[0175] In one implementation, the communication device 900 can implement the behaviors and functions of the terminal device in the above-mentioned method embodiment. The communication device 900 can be a terminal device, or a component (such as a chip or circuit) used in a terminal device, or a chip or chipset in the terminal device or a part of the chip used to perform the functions of the relevant method, or a software module capable of implementing the method executed by the terminal device in the above-mentioned method (such as communication method 400 and / or communication method 600, or communication method 800), without limitation. For details, please refer to the relevant content of the above-mentioned method embodiment, which will not be repeated here.

[0176] For example, the transceiver module 920 is configured to receive a first synchronization signal including a second synchronization index. The processing module 910 is configured to determine second ephemeris information based on the second synchronization index and a first association, determine a TA amount based on the second ephemeris information, and send a random access preamble based on the TA amount. The first association is an association between at least one synchronization index and at least one ephemeris information.

[0177] For another example, the transceiver module 920 is configured to receive a third synchronization signal from a first satellite, send a first random access preamble to the first satellite, receive a random access response message, and receive a synchronization signal from a second satellite on resources indicated by the resource information. The third synchronization signal is sent using resources within the first resource set. The random access response message includes ephemeris information and resource information of the second satellite, where the resource information indicates the resources used by the second satellite A to transmit the synchronization signal.

[0178] As an optional implementation, the processing module 910 is further configured to determine a first sub-resource set based on the first resource set and a second association relationship, where the second association relationship includes an association relationship between the first resource set and multiple sub-resource sets, where the multiple sub-resource sets are obtained by dividing the first resource set, and the first sub-resource set belongs to multiple sub-resource sets. The transceiver module 920 is specifically configured to send a first random access preamble to the first satellite using resources within the first sub-resource set.

[0179] When the communication device 900 is a chip-type device or circuit, the transceiver module may be an input / output circuit and / or a communication interface; the processing module may be an integrated processor or microprocessor or integrated circuit.

[0180] Figure 10 is a schematic block diagram of a communication device 1000 provided in an embodiment of the present application. The communication device 1000 can be a terminal device or a satellite (such as a first satellite or a second satellite) in the above-mentioned embodiment. For example, the communication device 1000 can be the terminal device in Figure 1 or a chip (system) in the terminal device. In the embodiment of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. For specific functions, please refer to the description in the above-mentioned method embodiment. For another example, the communication device 1000 can be the satellite in Figure 1 or a chip (system) in a satellite. In the embodiment of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. For specific functions, please refer to the description in the above-mentioned method embodiment.

[0181] The communication device 1000 includes one or more processors 1001, which are used to implement or support the communication device 1000 to implement the functions of the terminal device or satellite in the method provided in the embodiment of the present application. Please refer to the detailed description in the method example for details, which will not be repeated here. The processor 1001 can also be called a processing unit or a processing module, which can implement certain control functions. The processor 1001 can be a general-purpose processor or a dedicated processor. For example, it includes: a baseband processor, a central processing unit, an application processor, a modem processor, a graphics processor, an image signal processor, a digital signal processor, a video codec processor, a controller, a memory, and / or a neural network processor. The baseband processor can be used to process communication protocols and communication data. The central processing unit can be used to control the communication device 1000 (such as a satellite or terminal device), execute software programs and / or process data. Different processors can be independent devices or integrated into one or more processors, for example, integrated into one or more dedicated integrated circuits.

[0182] In one design, the processor 1001 may include a program 1003 (sometimes also referred to as code or instructions), which may be executed on the processor 1001 to cause the communication device 1000 to perform the methods described in the following embodiments. In another possible design, the communication device 1000 includes circuitry (not shown in FIG10 ) configured to implement the functions of the terminal device or satellite in the above embodiments.

[0183] In one design, the communication device 1000 may include one or more memories 1002, on which a program 1004 (sometimes also referred to as code or instructions) is stored. The program 1004 can be run on the processor 1001, so that the communication device 1000 performs the method described in the above method embodiment.

[0184] In one design, the processor 1001 and / or the memory 1002 may include an artificial intelligence (AI) module 1007 and an AI module 1008, each configured to implement AI-related functions. The AI ​​module may be implemented using software, hardware, or a combination of software and hardware. For example, the AI ​​module may include a RAN intelligent controller (RIC) module. For example, the AI ​​module may be a near-real-time RIC or a non-real-time RIC.

[0185] In a possible design, data may also be stored in the processor 1001 and / or the memory 1002. The processor and the memory may be provided separately or integrated together.

[0186] In one possible design, the communication device 1000 may further include a transceiver 1005 and / or an antenna 1006. The processor 1001 may also be sometimes referred to as a processing unit, which controls the communication device 1000. The transceiver 1005 may also be sometimes referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, and is configured to implement the transceiver functions of the communication device 1000 through the antenna 1006.

[0187] In one possible design, the communication device 1000 may further include one or more of the following components: a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display screen, etc. It will be appreciated that in some embodiments, the communication device 1000 may include more or fewer components, or some components may be integrated or separated. These components may be implemented in hardware, software, or a combination of software and hardware.

[0188] The communication device in the above embodiments can be a terminal device, a circuit, a chip used in a terminal device, or other devices or components combined with the above terminal devices. Alternatively, the communication device in the above embodiments can be a network device, a circuit, a chip used in a satellite, or other devices or components combined with the above network devices. When the communication device is a terminal device or a satellite, the transceiver module can be a transceiver, which can include an antenna and radio frequency circuits, etc., and the processing module can be a processor, such as a CPU. When the communication device is a system-on-chip, it can be an FPGA, a dedicated ASIC, a system-on-chip (SoC), a CPU, a network processor (NP), a DSP, a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated circuit. The processing module can be the processor of the system-on-chip. The transceiver module or communication interface can be the input / output interface or interface circuit of the system-on-chip. For example, the interface circuit can be a code / data read / write interface circuit. The interface circuit can be used to receive code instructions (the code instructions are stored in a memory and can be read directly from the memory or read from the memory via another device) and transmit them to the processor; the processor can be used to execute the code instructions to perform the method in the above method embodiment. For example, the interface circuit can also be a signal transmission interface circuit between a communication processor and a transceiver.

[0189] An embodiment of the present application further provides a communication system. Specifically, the communication system includes multiple satellites and at least one terminal device. The terminal device is a terminal device configured to implement the functions associated with at least one of the communication methods 400, 600, and 800 described above. The multiple satellites include a first satellite and a second satellite. The first satellite is a satellite configured to implement the functions associated with at least one of the communication methods 400, 600, and 800 described above. The second satellite is a satellite configured to implement the functions associated with at least one of the communication methods 400, 600, and 800 described above. For details, please refer to the relevant description in the above method embodiment and will not be repeated here.

[0190] In an embodiment of the present application, a computer-readable storage medium is also provided, comprising instructions, which, when executed on a computer, enables the computer to execute the method executed by the terminal device, the first satellite, or the second satellite in at least one of the above-mentioned communication methods 400, 600, and 800.

[0191] A computer program product is also provided in an embodiment of the present application, including computer program code. When the computer program code is executed, the computer executes the method executed by the terminal device, the first satellite or the second satellite in at least one of the above-mentioned communication methods 400, 600 and 800.

[0192] An embodiment of the present application provides a chip system, which includes a processor and may also include a memory, for implementing the functions of a terminal device, a first satellite, or a second satellite in at least one of the aforementioned methods 400, 600, and 800. The chip system may be composed of a chip or may include a chip and other discrete components.

[0193] To implement the functions of the communication device shown in Figures 9 and 10 , embodiments of the present application further provide a chip including a processor for supporting the communication device in implementing the functions of the terminal device or satellite in the above-described method embodiments. In one possible design, the chip is connected to or includes a memory for storing computer programs, instructions, and data necessary for the communication device.

[0194] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0195] Those skilled in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented using 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. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0196] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0197] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0198] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0199] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the part that essentially contributes to the technical solution of the present application or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks or optical disks.

[0200] Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include these modifications and variations.

Claims

1. A communication method, applied to a first satellite, characterized in that Including: Determine first information, the first information includes synchronization information of at least one second satellite, and the synchronization information of each of the second satellites includes at least one synchronization index; Transmit the first information.

2. The method according to claim 1, wherein The synchronization information of each of the second satellites further includes the time corresponding to the at least one synchronization index.

3. The method according to claim 1 or 2, characterized in that, The first information further includes: Ephemeris information of the at least one second satellite; or, Identification information of the at least one second satellite; or, Identification information of at least one transmit-receive point (TRP), where one TRP corresponds to one second satellite.

4. The method according to any one of claims 1 to 3, characterized in that, The at least one second satellite includes a plurality of second satellites, and the cell identifiers corresponding to the plurality of second satellites are the same.

5. The method according to claim 4, wherein The method further includes: Send second information to a second satellite A among the plurality of second satellites, the second information includes first time information and a first synchronization index, and is used to instruct the second satellite A to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information, where the time indicated by the first time information does not belong to the time when a second satellite B among the plurality of second satellites provides services based on the first synchronization index.

6. The method according to claim 5, characterized in that The method further includes: Receive third information from the second satellite B, the third information includes the first time information and the first synchronization index.

7. A communication method, applied to a second satellite, characterized in that Including: Determine a first synchronization signal, the first synchronization signal includes a second synchronization index, the second synchronization index is associated with the second ephemeris information, and the second ephemeris information is different from the ephemeris information associated with the synchronization index corresponding to other second satellites; Transmit the first synchronization signal.

8. The method according to claim 7, wherein The first synchronization signal further includes: The second ephemeris information, or, A first association relationship, the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information.

9. The method according to claim 7 or 8, characterized in that, The method further includes: Receive first information from a first satellite, the first information includes synchronization information of at least one second satellite, and the synchronization information of each of the second satellites includes at least one synchronization index.

10. The method according to claim 9, wherein The synchronization information of each of the second satellites further includes the time corresponding to the at least one synchronization index.

11. The method according to claim 9 or 10, characterized in that, The first information further includes: Ephemeris information of the at least one second satellite; or, Identification information of the at least one second satellite; or, Identification information of at least one transmit-receive point (TRP), where one TRP corresponds to one second satellite.

12. The method according to any one of claims 9 - 10, characterized in that, The method further includes: Receive second information from the first satellite, the second information includes first time information and a first synchronization index, and is used to instruct the second satellite to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information, where the time indicated by the first time information does not belong to the time when other second satellites provide services based on the first synchronization index; Send a second synchronization signal at the time indicated by the first time information, the second synchronization signal includes the first synchronization index.

13. The method according to claim 12, wherein The method further includes: Send fourth information to the first satellite, the fourth information includes second time information and a third synchronization index, and the third synchronization index cannot provide services at the time indicated by the second time information.

14. A communication method, applied to a terminal device, characterized in that, Including: Receive a first synchronization signal, where the first synchronization signal includes a second synchronization index; Determine second ephemeris information according to the second synchronization index and a first association relationship, where the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information; Determine a timing advance TA value according to the second ephemeris information; Send a random access preamble according to the timing advance value.

15. A communication method, applied to a first satellite, characterized in that, Includes: Use resources within a first resource set to send a third synchronization signal; Receive a first random access preamble from a terminal device; Determine a second satellite A according to the first random access preamble and a second association relationship, where the second association relationship includes an association relationship between a plurality of sub-resource sets and a plurality of second satellites, the resource of the first random access preamble belongs to a first sub-resource set among the plurality of sub-resource sets, and the second satellite A belongs to the plurality of second satellites; Send a random access response message to the terminal device, where the random access response message includes the ephemeris information and resource information of the second satellite A, and the resource information is used to indicate the resources for the second satellite A to send a synchronization signal.

16. The method according to claim 15, characterized in that The method further includes: Send fifth information, where the fifth information indicates the second association relationship, and the second association relationship further includes an association relationship between the plurality of sub-resource sets and the first resource set, where the plurality of sub-resource sets are obtained by dividing the first resource set.

17. A communication method, applied to a terminal device, characterized in that, Includes: Receive a third synchronization signal from a first satellite, where the third synchronization signal is sent using resources within a first resource set; Send a first random access preamble to the first satellite; Receive a random access response message, where the random access response message includes the ephemeris information and resource information of a second satellite, and the resource information is used to indicate the resources for the second satellite to send a synchronization signal; Receive a synchronization signal from the second satellite on the resources indicated by the resource information.

18. The method according to claim 17, wherein The method further includes: Determine a first sub-resource set according to the first resource set and a second association relationship, where the second association relationship includes an association relationship between the first resource set and a plurality of sub-resource sets, the plurality of sub-resource sets are obtained by dividing the first resource set, and the first sub-resource set belongs to the plurality of sub-resource sets; Send a first random access preamble to a first satellite, including: sending the first random access preamble to the first satellite using resources within the first sub-resource set.

19. A communication device, characterized in that, Includes: A processing module, configured to determine first information, where the first information includes synchronization information of at least one second satellite, and the synchronization information of each second satellite includes at least one synchronization index; A transceiver module, configured to send the first information.

20. The device according to claim 19, characterized in that, The synchronization information of each second satellite further includes the time corresponding to the at least one synchronization index.

21. The device according to claim 19 or 20, characterized in that, The first information further includes: The ephemeris information of the at least one second satellite; or, The identification information of the at least one second satellite; or, The identification information of at least one transmit receive point TRP, where one TRP corresponds to one second satellite.

22. The device according to any one of claims 19-21, characterized in that, The at least one second satellite includes a plurality of second satellites, and the cell identifiers corresponding to the plurality of second satellites are the same.

23. The device according to claim 22, wherein The transceiver module is further configured to: Send second information to satellite A among the multiple second satellites, where the second information includes first time information and a first synchronization index, and is used to instruct satellite A to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information, where the time indicated by the first time information does not belong to the time when satellite B among the multiple second satellites provides services based on the first synchronization index.

24. The device according to claim 23, characterized in that, The transceiver module is further configured to: Receive third information from satellite B, where the third information includes the first time information and the first synchronization index.

25. A communication device, characterized in that, It includes: A processing module, configured to determine a first synchronization signal, where the first synchronization signal includes a second synchronization index, the second synchronization index is associated with the second ephemeris information, and the second ephemeris information is different from the ephemeris information associated with the synchronization index corresponding to other second satellites; A transceiver module, configured to send the first synchronization signal.

26. The device according to claim 25, characterized in that, The first synchronization signal further includes: The second ephemeris information, or A first association relationship, where the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information.

27. The device according to claim 25 or 26, characterized in that, The transceiver module is further configured to: Receive first information from a first satellite, where the first information includes synchronization information of at least one of the communication devices, and the synchronization information of each communication device includes at least one synchronization index.

28. The device according to claim 27, wherein The synchronization information of each communication device further includes the time corresponding to the at least one synchronization index.

29. The device according to claim 27 or 28, characterized in that, The first information further includes: The ephemeris information of the at least one communication device; or The identification information of the at least one communication device; or The identification information of at least one transmit receive point (TRP), where one TRP corresponds to one communication device.

30. The device according to any one of claims 27-28, characterized in that, The transceiver module is further configured to: Receive second information from the first satellite, where the second information includes first time information and a first synchronization index, and is used to instruct the communication device to send a synchronization signal indicated by the first synchronization index at the time indicated by the first time information, where the time indicated by the first time information does not belong to the time when other second satellites provide services based on the first synchronization index; Send a second synchronization signal at the time indicated by the first time information, where the second synchronization signal includes the first synchronization index.

31. The device according to claim 30, characterized in that, The transceiver module is further configured to: Send fourth information to the first satellite, where the fourth information includes second time information and a third synchronization index, and the third synchronization index cannot provide services at the time indicated by the second time information.

32. A communication device, characterized in that, It includes: A transceiver module, configured to receive a first synchronization signal, where the first synchronization signal includes a second synchronization index; A processing module, configured to determine second ephemeris information according to the second synchronization index and the first association relationship, and determine a timing advance (TA) amount according to the second ephemeris information, where the first association relationship is an association relationship between at least one synchronization index and at least one ephemeris information; The transceiver module is further configured to send a random access preamble according to the timing advance amount.

33. A communication device, characterized in that, It includes: A transceiver module, configured to use resources within a first resource set to send a third synchronization signal and receive a first random access preamble from a terminal device; A processing module, configured to determine a second satellite A according to the first random access preamble and a second association relationship, where the second association relationship includes an association relationship between a plurality of sub-resource sets and a plurality of second satellites, a resource of the first random access preamble belongs to a first sub-resource set among the plurality of sub-resource sets, and the second satellite A belongs to the plurality of second satellites; The transceiver module is further configured to send a random access response message to the terminal device, where the random access response message includes ephemeris information and resource information of the second satellite A, and the resource information is used to indicate a resource for the second satellite A to send a synchronization signal.

34. The device according to claim 33, wherein The transceiver module is further configured to: Send fifth information, where the fifth information is used to indicate the second association relationship, and the second association relationship further includes an association relationship between the plurality of sub-resource sets and the first resource set, where the plurality of sub-resource sets are obtained by partitioning the first resource set.

35. A communication device, characterized in that, Comprising: A transceiver module, configured to send and receive a third synchronization signal from a first satellite, send a first random access preamble to the first satellite, receive a random access response message, and receive a synchronization signal from a second satellite on a resource indicated by resource information, where the third synchronization signal is sent using resources within a first resource set, the random access response message includes ephemeris information and resource information of the second satellite, and the resource information is used to indicate a resource for the second satellite to send a synchronization signal; A processing module, configured to determine the first random access preamble.

36. The apparatus according to claim 35, wherein The processing module is further configured to: determine a first sub-resource set according to the first resource set and the second association relationship, where the second association relationship includes an association relationship between the first resource set and a plurality of sub-resource sets, the plurality of sub-resource sets are obtained by partitioning the first resource set, and the first sub-resource set belongs to the plurality of sub-resource sets; The transceiver module is further configured to: send a first random access preamble to the first satellite, including: sending the first random access preamble to the first satellite using resources within the first sub-resource set.

37. A communication device, characterized in that, The communication apparatus includes a processor and a memory, the memory is configured to store a computer program, and the processor is configured to execute the computer program stored on the memory, so that the communication apparatus executes the method according to any one of claims 1 to 6, or so that the communication apparatus executes the method according to any one of claims 7 to 13, or so that the communication apparatus executes the method according to claim 14, or so that the communication apparatus executes the method according to any one of claims 15 to 16, or so that the communication apparatus executes the method according to any one of claims 17 to 18.

38. A communication system, characterized in that, The communication system includes a first satellite, a second satellite, and a terminal device. The first satellite is configured to execute the method according to any one of claims 1 to 6, the second satellite is configured to execute the method according to any one of claims 7 to 13, and the terminal device is configured to execute the method according to claim 14; or, the communication system includes a first satellite, a second satellite, and a terminal device. The first satellite is configured to execute the method according to any one of claims 15 to 16, and the terminal device is configured to execute the method according to any one of claims 17 to 18.

39. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program. When the computer program runs on a computer, the computer is caused to execute the method according to any one of claims 1 to 6, or the computer is caused to execute the method according to any one of claims 7 to 13, or the computer is caused to execute the method according to claim 14, or the computer is caused to execute the method according to any one of claims 15 to 16, or the computer is caused to execute the method according to any one of claims 17 to 18.

40. A computer program product, characterized in that, The computer program product includes a computer program. When the computer program runs on a computer, the computer is caused to execute the method according to any one of claims 1 to 6, or the computer is caused to execute the method according to any one of claims 7 to 13, or the computer is caused to execute the method according to claim 14, or the computer is caused to execute the method according to any one of claims 15 to 16, or the computer is caused to execute the method according to any one of claims 17 to 18.

41. A chip system, characterized in that, The chip system includes: a processor and an interface. The processor is configured to call and run instructions from the interface. When the processor executes the instructions, the method according to any one of claims 1 to 6 is implemented, or the method according to any one of claims 7 to 13 is implemented, or the method according to claim 14 is implemented, or the method according to any one of claims 15 to 16 is implemented, or the method according to any one of claims 17 to 18 is implemented.

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