Communication method and apparatus

Abstract

The application provides a communication method and device, which can reduce signaling overhead and transmission delay, and can be applied to a communication system. The method comprises the following steps: a terminal device receives first information from a first satellite, and determines a first timing advance according to the position of the terminal device and the first information. The first information is used to indicate ephemeris information of a second satellite. The first timing advance is used to indicate a time length in advance for eliminating transmission delay of data sent by the terminal device to the second satellite.

Description

Technical Field

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

[0002] Satellite communication offers advantages such as wide coverage and resistance to natural disasters or external damage, providing superior communication services. However, in satellite communication scenarios, the high speed of satellite movement necessitates that terminal devices perform random access procedures to achieve uplink synchronization when switching satellites. This results in high signaling overhead and significant latency. Summary of the Invention

[0003] This application provides a communication method and apparatus that can reduce signaling overhead and transmission latency.

[0004] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, a communication method is provided. The communication method includes: a terminal device receiving first information from a first satellite. The first information is used to indicate ephemeris information of a second satellite. The terminal device determines a first timing advance based on its position and the first information. The first timing advance indicates the length of time advanced to eliminate transmission delay of data sent by the terminal device to the second satellite.

[0005] Based on the communication method provided in the first aspect, the terminal device can receive the first information from the first satellite in advance and determine the first timing advance based on the location of the terminal device and the first information. In this way, the terminal device can obtain the timing advance for sending data to the second satellite before the satellite handover, avoid executing the random access procedure, and thus reduce signaling overhead and transmission delay.

[0006] In one possible design, the first timing advance includes the timing advance TA of the service link of the second satellite. Alternatively, the first timing advance includes both the TA of the service link of the second satellite and the TA of the feeder link. The TA of the service link of the second satellite indicates the time length by which the transmission delay of data sent from the terminal device to the second satellite on the service link of the second satellite is eliminated, and the TA of the feeder link indicates the time length by which the transmission delay of data sent from the terminal device to the second satellite on the feeder link of the second satellite is eliminated. This allows for data transmission to both transparent and non-transparent satellite architectures, improving adaptability.

[0007] Optionally, the first information is also used to indicate the TA of the feed link of the second satellite.

[0008] In one possible design, the first information is further used to indicate the time when the second satellite will provide network services to the terminal device. The method provided by the first aspect may also include: the terminal device transmitting data according to the time when the second satellite will provide network services to the terminal device, and a first timing advance. Thus, the terminal device can transmit data according to the first timing advance, thereby reducing signaling overhead and transmission latency.

[0009] Optionally, the terminal device sending data based on the time when the second satellite provides network services to the terminal device and the first timing advance may include: the terminal device acquiring the second timing advance. The second timing advance indicates the length of time advanced to eliminate the transmission delay of data transmission from the terminal device to the first satellite. The terminal device determines the overlapping time period of the first time period and the second time period based on the second timing advance, the time when the second satellite provides network services to the terminal device, and the first timing advance. The first time period is the time period for sending the first portion of the first data to the first satellite, and the second time period is the time period for sending the second portion of the first data to the second satellite. If the length of the overlapping time period is greater than or equal to a first duration threshold, the terminal device sends the data corresponding to the first sub-time period in the first portion of the data to the first satellite, and sends the second portion of the data to the second satellite. The first sub-time period is the time period within the first time period excluding the overlapping time period. Alternatively, the terminal device sends the first portion of the data to the first satellite, and sends the data corresponding to the second sub-time period in the second portion of the data to the second satellite. The second sub-time period is the time period within the second time period excluding the overlapping time period. This avoids overlapping data transmission time periods, reduces interference between data, and improves the transmission success rate.

[0010] Alternatively, the method provided in the first aspect may further include: the terminal device receiving second information from the first satellite. The second information indicates a third time period, the length of which is the interval between the moment the first satellite stops transmitting information or the end of the terminal device's scheduling waiting period, and the start time of the second satellite receiving uplink data from the terminal device. The terminal device sending data according to the time the second satellite provides network services to the terminal device and a first timing advance may include: the terminal device sending first uplink data according to the third time period, the time the second satellite provides network services to the terminal device, and the first timing advance. This delays the time the second satellite receives data, thereby avoiding data overlap between different satellites and improving communication efficiency.

[0011] Furthermore, the terminal device sends the first uplink data according to the third time period, the time when the second satellite provides network services to the terminal device, and the first timing advance. This may include: if the transmission time period of the first uplink data overlaps with the third time period, then the data corresponding to the third sub-time period in the first uplink data is sent to the second satellite. The third sub-time period is the time period in the transmission time period excluding the overlapping time period.

[0012] In one possible design, the method provided by the first aspect may further include: receiving third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the terminal device and the second satellite. If the second duration is less than the third duration, the terminal device performs downlink synchronization with the second satellite within the third duration following the second duration. This approach balances the downlink synchronization process with the waiting time for data transmission to the second satellite.

[0013] In one possible design, the method provided by the first aspect may further include: receiving third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the terminal device and the second satellite. If the second duration is greater than or equal to the third duration, the terminal device performs downlink synchronization with the second satellite within the second duration. This balances the downlink synchronization process with the waiting time for data transmission to the second satellite.

[0014] In one possible design, the method provided in the first aspect may further include: a terminal device receiving a synchronization signal and a broadcast channel block (SSB) from a second satellite. The SSB is used to indicate the Physical Cell Identifier (PCI) of the second satellite. The terminal device obtains the PCI of the second satellite based on the SSB. Thus, the PCI of the second satellite can be obtained through the SSB, given both the PCI of the second satellite and the PCI of the first satellite, thereby reducing the amount of data in the first information and further reducing signaling overhead.

[0015] In one possible design, the first information can also be used to indicate the PCI of the second satellite. This allows the terminal device to avoid obtaining the PCI based on the SSB, simplifying the terminal device's processing.

[0016] In one possible design, the first information includes dedicated signaling for the terminal device, and the time for the second satellite to provide network services to the terminal device can be carried in one or more of the following: RRC signaling, MAC CE, or DCI. Thus, when the first and second satellites are operating in non-staring mode, the time for the second satellite to provide network services to each terminal device can be configured, thereby further improving communication reliability.

[0017] Optionally, the time for downlink synchronization by the terminal device is carried in one or more of the following: RRC signaling, MACCE, or DCI.

[0018] Secondly, a communication method is provided. This communication method includes: a first satellite determining first information; the first satellite transmitting the first information to a terminal device; wherein the first information is used to indicate ephemeris information of a second satellite.

[0019] In one possible design, the first satellite is the one currently providing network services to the terminal device, and the second satellite is the one that the terminal device will switch to.

[0020] In one possible design, the method provided by the second aspect may further include: a first satellite sending second information to a terminal device. The second information indicates a third time period, the length of which is the interval between the moment the first satellite stops transmitting information or the end of the terminal device's scheduling waiting period and the start time of the second satellite receiving uplink data from the terminal device.

[0021] In one possible design, the first information can also be used to indicate the PCI of the second satellite.

[0022] In one possible design, the method provided by the second aspect may further include: the first satellite sending third information to the terminal device. The third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the terminal device and the second satellite.

[0023] Furthermore, the technical effects of the communication method described in the second aspect can be referred to the technical effects of the communication method described in the first aspect, and will not be repeated here.

[0024] Thirdly, a communication device is provided. The communication device includes a transceiver module and a processing module. The transceiver module is used to receive first information from a first satellite. The first information is used to indicate ephemeris information of a second satellite. The processing module is used to determine a first timing advance based on the position of the communication device and the first information. The first timing advance indicates the length of time advanced to eliminate the transmission delay of data sent by the communication device to the second satellite.

[0025] In one possible design, the first satellite is the one currently providing network services to the communication device, and the second satellite is the one the communication device is about to switch to. In another possible design, the first timing advance includes the timing advance TA of the service link of the second satellite. Alternatively, the first timing advance includes both the TA of the service link of the second satellite and the TA of the feeder link. The TA of the service link of the second satellite indicates the time advance required to eliminate the transmission delay of data sent by the communication device to the second satellite on the service link of the second satellite, and the TA of the feeder link indicates the time advance required to eliminate the transmission delay of data sent by the communication device to the second satellite on the feeder link of the second satellite.

[0026] Optionally, the first information is also used to indicate the TA of the feed link of the second satellite.

[0027] In one possible design, the first information is also used to indicate the time when the second satellite provides network services to the communication device, and the transceiver module is also used to transmit data according to the second satellite providing network services to the communication device and the first timing advance.

[0028] Optionally, the transceiver module is specifically used to obtain a second timing advance from the first satellite. Based on the second timing advance, the time when the second satellite provides network services to the communication device, and the first timing advance, the overlapping time period of the first time period and the second time period is determined. The first time period is the time period for transmitting the first portion of the first data to the first satellite, and the second time period is the time period for transmitting the second portion of the first data to the second satellite. If the length of the overlapping time period is greater than or equal to a first duration threshold, the communication device transmits data corresponding to the first sub-time period from the first portion of the data to the first satellite, and transmits the second portion of the data to the second satellite; the first sub-time period is the time period within the first time period excluding the overlapping time period. Alternatively, the communication device transmits the first portion of the data to the first satellite, and transmits data corresponding to the second sub-time period from the second portion of the data to the second satellite. The second sub-time period is the time period within the second time period excluding the overlapping time period. The second timing advance is used to indicate the time length advanced to eliminate the transmission delay of the data transmitted by the communication device to the first satellite.

[0029] Alternatively, the transceiver module may also be configured to receive second information from the first satellite. The second information indicates a third time period, the length of which is the interval between the moment the first satellite stops transmitting information or the end of the scheduling waiting period for the communication device and the start time of the second satellite receiving uplink data from the communication device. Specifically, the transceiver module is configured to send first uplink data based on the third time period, the time the second satellite provides network services to the communication device, and a first timing advance. The duration between the moment the communication device begins sending fifth data to the second satellite and the second moment is less than or equal to the first timing advance.

[0030] Furthermore, the transceiver module is specifically used to: when there is an overlap between the transmission time period of the first uplink data and the third time period, transmit the data corresponding to the third sub-time period in the first uplink data to the second satellite, wherein the third sub-time period is the time period in the transmission time period excluding the overlapping time period.

[0031] In one possible design, the transceiver module is further configured to receive third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the communication device and the second satellite. If the second duration is less than the third duration, the communication device will perform downlink synchronization with the second satellite during the third duration following the second duration.

[0032] In one possible design, the transceiver module is further configured to receive third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the communication device and the second satellite. If the second duration is greater than or equal to the third duration, the communication device performs downlink synchronization with the second satellite within the second duration.

[0033] In one possible design, the transceiver module is further configured to receive synchronization signals and broadcast channel blocks (SSBs) from the second satellite. The SSBs indicate the Physical Cell Identifier (PCI) of the second satellite. The processing module is further configured to obtain the PCI of the second satellite based on its SSBs.

[0034] In one possible design, the first information can also be used to indicate the PCI of the second satellite.

[0035] In one possible design, the first information includes dedicated signaling for the communication device, and the second satellite's provision of network services to the communication device can be carried in one or more of the following: RRC signaling, MAC CE, or DCI.

[0036] Optionally, the downlink synchronization time of the communication device is carried in one or more of the following: RRC signaling, MACCE, or DCI.

[0037] Optionally, the transceiver module may include a receiving module and a sending module. The transceiver module is used to implement the sending and receiving functions of the communication device described in the third aspect.

[0038] Optionally, the communication device described in the third aspect may further include a storage module storing programs or instructions. When the processing module executes the program or instructions, the communication device can perform the communication method described in the first aspect.

[0039] The communication device described in the third aspect may be a terminal device, or a chip (system) or other component or assembly that can be disposed in the terminal device, or a device that includes the terminal device. This application does not limit the scope of the application.

[0040] Furthermore, the technical effects of the communication device described in the third aspect can be referred to the technical effects of the communication method described in the first aspect, and will not be repeated here.

[0041] Fourthly, a communication device is provided. The communication device includes a processing module and a transceiver module. The processing module is used to determine first information. The transceiver module is used to send the first information to a terminal device. The first information is used to indicate the ephemeris information of a second satellite.

[0042] In one possible design, the communication device is the satellite currently providing network services to the terminal device, and the second satellite is the satellite that the terminal device will switch to.

[0043] In one possible design, the transceiver module is further configured to send second information to the terminal device. The second information indicates a first time period, and the length of the third time period is the interval between the moment the communication device stops transmitting information or the end of the terminal device's scheduling waiting period and the start time of the second satellite receiving uplink data from the terminal device.

[0044] In one possible design, the first information can also be used to indicate the PCI of the second satellite.

[0045] In one possible design, the transceiver module is also used to send third information to the terminal device. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the terminal device and the second satellite.

[0046] Optionally, the transceiver module may include a receiving module and a transmitting module. The transceiver module is used to implement the transmitting and receiving functions of the communication device described in the fourth aspect.

[0047] Optionally, the communication device described in the fourth aspect may further include a storage module storing programs or instructions. When the processing module executes the program or instructions, the communication device can perform the communication method described in the second aspect.

[0048] The communication device described in the fourth aspect may be a first satellite, or a chip (system) or other component or assembly that can be disposed in the first satellite, or a device that includes the first satellite. This application does not limit this.

[0049] Furthermore, the technical effects of the communication device described in the fourth aspect can be referred to the technical effects of the communication method described in the first aspect, and will not be repeated here.

[0050] Fifthly, a communication device is provided. This communication device is used to execute the communication method described in any one of the implementations of the first to second aspects.

[0051] In this application, the communication device described in the fifth aspect may be the terminal device described in the first aspect or the first satellite described in the second aspect, or may be a chip (system) or other component or assembly disposed in the terminal device or the first satellite, or may include the terminal device or the first satellite.

[0052] It should be understood that the communication apparatus described in the fifth aspect includes modules, units, or means that implement the communication methods described in any of the first to second aspects. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units for performing the functions involved in the aforementioned communication methods.

[0053] Furthermore, the technical effects of the communication device described in the fifth aspect can be referred to the technical effects of the communication method described in any one of the first or second aspects, and will not be repeated here.

[0054] A sixth aspect provides a communication device. The communication device includes a processor configured to execute the communication method described in any of the possible implementations of the first to second aspects.

[0055] In one possible design, the communication device described in the sixth aspect may further include a transceiver. This transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device described in the sixth aspect and other communication devices.

[0056] In one possible design, the communication device described in the sixth aspect may further include a memory. This memory may be integrated with the processor or disposed separately. The memory may be used to store computer programs and / or data related to the communication method described in any of the first to second aspects.

[0057] In this application, the communication device described in the sixth aspect may be the terminal device in the first aspect or the first satellite in the second aspect, or may be a chip (system) or other component or assembly disposed in the terminal device or the first satellite, or may include the terminal device or the first satellite.

[0058] Furthermore, the technical effects of the communication device described in the sixth aspect can be referred to the technical effects of the communication method described in any of the implementations of the first to second aspects, and will not be repeated here.

[0059] A seventh aspect provides a communication device. The communication device includes a processor coupled to a memory, the processor being configured to execute a computer program stored in the memory, such that the communication device performs the communication method described in any possible implementation of the first to second aspects.

[0060] In one possible design, the communication device described in the seventh aspect may further include a transceiver. This transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device described in the seventh aspect and other communication devices.

[0061] In this application, the communication device described in the seventh aspect may be the terminal device in the first aspect or the first satellite in the second aspect, or may be a chip (system) or other component or assembly disposed in the terminal device or the first satellite, or may include the terminal device or the first satellite.

[0062] Furthermore, the technical effects of the communication device described in the seventh aspect can be referred to the technical effects of the communication method described in any of the implementations of the first to second aspects, and will not be repeated here.

[0063] Eighthly, a communication device is provided, comprising: a processor and a memory; the memory is used to store a computer program, which, when executed by the processor, causes the communication device to perform the communication method described in any one of the first to second aspects.

[0064] In one possible design, the communication device described in the eighth aspect may further include a transceiver. This transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device described in the eighth aspect and other communication devices.

[0065] In this application, the communication device described in the eighth aspect may be the terminal device in the first aspect or the first satellite in the second aspect, or may be a chip (system) or other component or assembly disposed in the terminal device or the first satellite, or may include the terminal device or the first satellite.

[0066] Furthermore, the technical effects of the communication device described in the eighth aspect can be referenced from the technical effects of the communication method described in any of the implementations of the first to second aspects, and will not be repeated here.

[0067] A ninth aspect provides a communication device comprising: a processor; the processor being configured to be coupled to a memory, and after reading a computer program from the memory, to execute a communication method as described in any one of the implementations of the first to second aspects according to the computer program.

[0068] In one possible design, the communication device described in the ninth aspect may further include a transceiver. This transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the communication device described in the ninth aspect and other communication devices.

[0069] In this application, the communication device described in the ninth aspect may be the terminal device in the first aspect or the first satellite in the second aspect, or may be a chip (system) or other component or assembly disposed in the terminal device or the first satellite, or may include the terminal device or the first satellite.

[0070] Furthermore, the technical effects of the communication device described in the ninth aspect can be referenced from the technical effects of the communication method described in any of the implementations of the first to second aspects, and will not be repeated here.

[0071] Furthermore, the technical effects of the communication devices described in the fifth to ninth aspects above can be referred to the technical effects of the communication methods described in the first to second aspects above, and will not be repeated here.

[0072] A tenth aspect provides a processor. The processor is configured to execute the communication method described in any of the possible implementations of the first to second aspects.

[0073] Eleventhly, a communication system is provided. The communication system includes one or more terminal devices and one or more first satellites.

[0074] In a twelfth aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are executed on a computer, causing the computer to perform the communication method described in any possible implementation of the first to second aspects.

[0075] In a thirteenth aspect, a computer program product is provided, comprising a computer program or instructions that, when executed on a computer, cause the computer to perform the communication method described in any possible implementation of the first to second aspects. Attached Figure Description

[0076] Figure 1 A schematic diagram illustrating the coverage area of ​​the gaze pattern provided in an embodiment of this application; Figure 2 This is a schematic diagram of the architecture of the communication system provided in the embodiments of this application; Figure 3 A flowchart illustrating the communication method provided in an embodiment of this application; Figure 4 A data transmission schematic diagram provided for an embodiment of this application; Figure 5 This is another data transmission diagram provided as an embodiment of the present application; Figure 6 This application provides another data transmission schematic diagram. Figure 7 This application provides another data transmission schematic diagram. Figure 8 This application provides another data transmission schematic diagram. Figure 9 This application provides another data transmission schematic diagram. Figure 10 Schematic diagram of the communication device provided in the embodiments of this application Figure 1 ; Figure 11 Schematic diagram of the communication device provided in the embodiments of this application Figure 2 . Detailed Implementation

[0077] The following section first introduces the technical terms related to the embodiments of this application.

[0078] 1. Timing Advance: Also known as timing advance, this refers to the transmission delay caused by distance during the process of an uplink signal from a terminal device reaching a network device. When a terminal sends an uplink signal, it needs to compensate for the uplink signal according to the timing advance (TA) to ensure that the uplink signal is aligned with the uplink synchronization point. For example, if a terminal device sends an uplink signal to a network device and expects the uplink signal to arrive at the network device at time T1, and the transmission delay between the terminal device and the network device is TA1, then the terminal device can send the uplink signal between T1 and TA1.

[0079] In existing satellite communication scenarios, a satellite can function as a network device, such as a base station, or as a transparent forwarding node. When the satellite acts as a network device, the uplink signal is synchronized on the satellite side; that is, the satellite is the uplink synchronization point. When the satellite acts as a transparent forwarding node, the uplink synchronization point can be the satellite itself, a network device such as a base station, or any location in the wireless link (feed link) between the satellite and the ground-based network device. In this case, TA represents the transmission delay between the terminal device and the uplink synchronization node.

[0080] In the case where the satellite acts as a transparent relay node, the TA (Transmission Target) can include the TA of the service link and the transmission delay between the terminal device and the satellite. The terminal can determine the TA of the service link based on its own location and satellite ephemeris.

[0081] When a satellite is used as a network device, the TA (Transmission Terminal) can include the TA for the serving link and the TA for the common link. The TA for the common link refers to the delay between the satellite and the synchronization point. The feeder link TA is the same for all terminal devices within the satellite's service area, and the satellite can broadcast the feeder link TA to all terminal devices within its service area.

[0082] 2. Staring mode: The satellite adjusts the beam direction through beamforming to serve the same service area. When the satellite elevation angle is greater than the elevation angle threshold and a switch is required, all users in the service area will switch to the next satellite.

[0083] For example, such as Figure 1 As shown, satellite 1 serves area A. In staring mode, when the elevation angle of satellite A is greater than the elevation angle threshold, satellite 2 adjusts its beam direction through beamforming, thus making its service area area area A. The elevation angle threshold can be 30 degrees or 40 degrees. In specific implementations, the elevation angle threshold can be determined according to the specific scenario, which will not be elaborated here.

[0084] 3. Non-staring mode: The satellite hardly adjusts its beam direction. The service area on the ground corresponding to the satellite beam moves with the satellite. Therefore, users in different locations within the same service area do not switch to the next satellite at the same time.

[0085] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0086] Non-terrestrial networks (NTNs), including nodes such as satellite networks, high-altitude platforms, and drones, offer significant advantages such as global coverage, long-distance transmission, flexible networking, convenient deployment, and freedom from geographical limitations. They have been widely applied in various fields including maritime communication, positioning and navigation, disaster relief, scientific experiments, video broadcasting, and Earth observation. The integration of terrestrial 5G mobile networks and satellite networks leverages their respective strengths to create a seamless, globally integrated sea, land, air, and space communication network, meeting users' ubiquitous and diverse service needs.

[0087] As an important component of NTN, next-generation satellite networks are generally characterized by ultra-dense and heterogeneous structures. Satellite networks exhibit heterogeneous characteristics, evolving from traditional single-layer communication networks to multi-layer communication networks. The functions of communication satellite networks are also becoming more complex and diversified, gradually becoming compatible with and supporting functions such as navigation enhancement, Earth observation, and on-orbit processing of multi-dimensional information.

[0088] The technical solutions of this application can be applied to NTN systems such as satellite communication systems, high altitude platform station (HAPS) communication, and unmanned aerial vehicles (UAVs), including integrated communication and navigation (ICAN) systems, global navigation satellite systems (GNSS), and ultra-dense low-Earth orbit (LEO) satellite communication systems. Satellite communication systems can be integrated with traditional mobile communication systems. For example, the mobile communication system can be a 4th generation (4G) communication system (e.g., Long Term Evolution (LTE) system), a worldwide interoperability for microwave access (WiMAX) communication system, a 5G communication system (e.g., a new radio (NR) system), and future mobile communication systems.

[0089] This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0090] Furthermore, in the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as an "example" in this application should not be construed as being better or more advantageous than other embodiments or designs. Rather, the use of the word "example" is intended to present the concept in a specific manner.

[0091] The terms “first,” “second,” etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0092] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c; a and b; a and c; b and c; or a and b and c. Here, a, b, and c can be single or multiple.

[0093] To facilitate understanding of the embodiments of this application, the following describes the background technology related to the embodiments of this application.

[0094] Satellite communication has unique advantages over terrestrial communication. For example, it can provide wider coverage; satellites are less susceptible to damage from natural disasters or external forces. Introducing satellite communication into communication systems, such as 5G systems, can provide communication services to areas inaccessible to terrestrial networks, such as oceans and forests, thereby enhancing communication reliability. For instance, it can ensure that users on airplanes, trains, and other modes of transportation receive higher-quality communication services. Furthermore, it can provide more resources for data transmission, improving network speeds.

[0095] Satellite communication has been incorporated into the 3rd Generation Partnership Project (3GPP) standards. Communication systems incorporating satellite communication are also known as NTN (Network Telecommunication Network). These systems can support not only various terminal devices in 5G communication scenarios but also Internet of Things (IoT) type terminal devices.

[0096] In terrestrial networks (NT), when a terminal device performs a cell handover, it can synchronize with the target cell by executing a random access procedure.

[0097] Currently, when a terminal device performs a satellite handover, it typically needs to re-initiate a random access request to the target satellite to achieve uplink synchronization (uplink time-frequency synchronization). However, due to the high speed of satellite movement, the terminal device needs to perform satellite handovers frequently. This requires the terminal device to frequently execute random access procedures, resulting in high signaling overhead.

[0098] Furthermore, if a satellite handover occurs during data transmission, the data not fully transmitted on the source satellite must complete the random access procedure before it can continue to be transmitted on the target satellite, leading to significant data latency. For IoT-type terminal devices, current protocols support a very high number of repetitions, and the time required to transmit a single transport block (TB) is relatively long, making the data latency issue caused by satellite handover even more pronounced.

[0099] The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0100] To facilitate understanding of the embodiments of this application, the following is combined with Figure 2 The communication system shown in the figure is used as an example to describe in detail the communication system applicable to the embodiments of this application.

[0101] The communication system in this application embodiment may include a transparent satellite architecture and a non-transparent satellite architecture. Transparent transmission, also known as bend-tube relay transmission, means that the signal only undergoes frequency conversion and signal amplification on the satellite; the satellite is transparent to the signal, as if it doesn't exist. Non-transparent transmission can be called regenerative (on-board access / processing) transmission, meaning that the satellite has some or all of the base station functions. The satellite mentioned in this application embodiment can be a satellite base station, or it may include an orbital receiver or repeater for relaying information, or network-side equipment mounted on the satellite; the satellite can be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a high Earth orbit (HEO) satellite, a geostationary orbit (GEO) satellite, or a non-geostationary orbit (NGEO) satellite, etc. This application does not impose any limitations on this.

[0102] For example, Figure 2 This is a schematic diagram of the architecture of a communication system to which the communication method provided in the embodiments of this application is applicable.

[0103] like Figure 2 As shown, the communication system includes terminal equipment 201, at least one satellite (202a to 202f), at least one connection device (203a, 203b), and core network 205.

[0104] Among them, terminal device 201 can establish a communication connection with satellites (202a to 202f) wirelessly. Satellite 202a communicates with connection device 203a, connection device 203a communicates with network device 204, network device 204 communicates with core network (CN) 205, satellite 202d communicates with connection device 203b, connection device 203b communicates with core network 205, and core network 205 communicates with data network 206.

[0105] Furthermore, in this embodiment, communication connections can be established between satellites 202a and 202b, and between satellites 202a and 202c. Communication connections can also be established between satellites 202d and 202e, and between satellites 202d and 202f.

[0106] Terminal device 201 can communicate with satellites (202a to 202f) via air interface. Satellite 202a can communicate with connection device 203a via air interface, and network device 204 can communicate with core network 205 via NG interface. Satellite 202b can communicate with connection device 203b via air interface, and connection device 203b can communicate with core network 205 via NG interface. Furthermore, satellites 202e and 202d can communicate via Xn interface. In other words, satellite 202a can adopt a transparent transmission satellite architecture, meaning it is used for signal transmission. Satellite 202b can adopt a non-transparent transmission satellite architecture, meaning it is used to implement some or all of the functions of the network device.

[0107] It is understandable that the aforementioned Satellite 202a could also adopt a non-transparent satellite architecture; for details on its implementation, please refer to [reference needed]. Figure 2 The implementation principle of the non-transparent satellite architecture used in satellite 202b is not described in detail here. Satellite 202b can also use a transparent satellite architecture; the specific implementation principle can be found in the implementation principle of the transparent satellite architecture used in satellite 202a, which will not be described in detail here.

[0108] It is understandable that the satellites in the aforementioned communication systems can also be aircraft, unmanned aerial systems (UAS), drones, etc.

[0109] The aforementioned network device is a device located on the network side of the aforementioned communication system and possessing wireless transceiver capabilities, or a chip or chip system that can be installed in the device. This network device includes, but is not limited to, satellites, aircraft, or unmanned aerial systems (UAS). Alternatively, the network device may be a device installed on a satellite, aircraft, or UAS and possessing wireless transceiver capabilities, or a chip or chip system that can be installed in the device. Alternatively, the network device can be an evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), baseband unit (BBU), wireless relay node, wireless backhaul node, transmission and reception point (TRP or transmission point, TP), etc. It can also be a 5G device, such as a gNB in ​​a new radio (NR) system, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or transmission point, such as a baseband unit (BBU) or a distributed unit (DU), etc.

[0110] The aforementioned terminal device is a terminal that accesses the aforementioned communication system and has wireless transceiver capabilities, or a chip or chip system that can be installed in the terminal. This terminal device can also be referred to as a satellite television receiver, user device, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment. In the embodiments of this application, the terminal device can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical care, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, vehicle-mounted terminal, RSU with terminal functionality, etc. The terminal device of this application may also be an on-board module, on-board component, on-board chip or on-board unit built into a vehicle as one or more components or units. The vehicle can implement the frequency offset compensation method provided in this application through the built-in on-board module, on-board component, on-board chip or on-board unit.

[0111] The core network can be used for services such as user access control, mobility management, session management, user authentication, and billing. It consists of multiple functional units, including control plane functional entities and data plane functional entities. For example, control plane functional entities may include the access and mobility management function (AMF) entity, which is responsible for user access management, authentication, and mobility management. The user plane function (UPF) is responsible for managing user plane data transmission, traffic statistics, and other functions.

[0112] Connectivity devices, also known as ground stations or gateways, are responsible for forwarding signaling and service data between satellite base stations and the core network.

[0113] The air interface refers to the wireless link between the terminal and the base station.

[0114] The Xn interface refers to the interface between base stations, which is mainly used for signaling interactions such as handover.

[0115] The NG interface refers to the interface between the base station and the core network, which mainly exchanges signaling such as NAS of the core network and user service data.

[0116] It is understandable that the Xn interface and NG interface may have different names in different communication systems. For example, in a 4G communication system, the Xn interface is called the X2 interface and the NG interface is called the S1 interface.

[0117] Furthermore, it is understandable that the above Figure 2 Any one of the satellites 202a to 202b shown can operate in either staring mode or non-staring mode.

[0118] The communication method provided in this application embodiment can be applied to Figure 2 The specific implementation between the terminal device and the satellite can be referred to the following method embodiments, which will not be repeated here.

[0119] It should be noted that the solutions in the embodiments of this application can also be applied to other communication systems, and the corresponding names can be replaced by the names of the corresponding functions in other communication systems.

[0120] For ease of understanding, the following embodiments use satellite 202a as a transparent transmission satellite and satellite 202d as an example of containing some or all of the functions of a base station. In actual implementation, satellite 202a contains some or all of the functions of a base station, and / or satellite 202d is a transparent transmission satellite, which will not be elaborated here.

[0121] The following will combine Figures 3-9 The communication method provided in the embodiments of this application will be described in detail.

[0122] For example, Figure 3 This is a flowchart illustrating the communication method provided in an embodiment of this application. This communication method can be applied to... Figure 2 The terminal device shown communicates with the satellite.

[0123] like Figure 3 As shown, the communication method includes the following steps: S301, the first satellite transmits the first information. Correspondingly, the terminal equipment receives the first information.

[0124] The first piece of information is used to indicate the ephemeris information of the second satellite.

[0125] The first information may also include the measurement configuration information of the second satellite, wherein the measurement configuration information may include one or more of the following of the second satellite: transmission power, power threshold, neighboring cell frequency, frequency point, ephemeris of neighboring satellites, or measurement time.

[0126] For example, the first satellite may be the satellite currently providing network services to the terminal device, and the second satellite may be the satellite that the terminal device is about to switch to.

[0127] For example, the first satellite could be as described above. Figure 2 Satellite 202a in the middle, the second satellite can be the one mentioned above. Figure 2 The first satellite may be any one of satellites 202d, 202e, or 202f. Alternatively, the first satellite may be one of the aforementioned satellites. Figure 2 Satellite 202d in the middle, the second satellite can be the one mentioned above. Figure 2 The first satellite may be any one of satellites 202a, 202b, or 202c. Alternatively, the first satellite may be one of the aforementioned satellites. Figure 2 The second satellite is one of satellites 202b and 202c shown. In this case, the second satellite is any one of satellites 202b and 202c other than the first satellite, and any one of satellites 202d to 202f. Alternatively, the first satellite can be one of the above-mentioned... Figure 2 The second satellite is one of satellites 202e and 202f shown, and the second satellite is any one of satellites 202e and 202f other than the first satellite, as well as any one of satellites 202a to 202c.

[0128] The ephemeris information of the second satellite is used to indicate its operational information. This includes, for example, relevant coordinate information such as Earth-centered (ECEF) or Earth-centered inertial (ECI) coordinates, as well as orbital information. ECEF coordinate information may include the coordinates of three points related to the second satellite, its velocity, and time. ECI coordinate information may also include the coordinates of three points related to the second satellite, its velocity, and time. Orbital information includes the right ascension of the ascending node, orbital inclination, semi-major axis, orbital eccentricity, perigee angle, and true anomaly angle.

[0129] In one possible design, the Physical Cell Identifier (PCI) of the terminal device remains unchanged before and after satellite switching; that is, the PCI of the first satellite is different from the PCI of the second satellite after the switch. In this case, the terminal device can avoid obtaining the PCI of the second satellite. The scrambling information for data transmitted between the terminal device and the satellite can be determined based on the PCI; the specific principle can be found in existing technologies and will not be elaborated here.

[0130] Optionally, if the terminal device does not perform downlink synchronization, or if the terminal device performs downlink synchronization and only detects the primary synchronization signal (PSS) during the downlink synchronization process, the terminal device can obtain the PCI through the first information. That is, the first information may also include the PCI of the second satellite.

[0131] It is understandable that if the PCI changes between the first satellite before and the second satellite after the handover, the terminal device can also obtain the PCI itself. For example, the terminal device receives a synchronization signal and physical broadcast channel block (SSB) from the second satellite. The terminal device obtains the Physical Cell Identifier (PCI) of the second satellite based on the SSB. The implementation principle of the terminal device obtaining the PCI of the second satellite based on the SSB can be found in existing technologies, and will not be elaborated here.

[0132] The first satellite can also send broadcast messages other than the SSB to the terminal device. Correspondingly, the terminal device can receive broadcast messages other than the SSB from the first satellite.

[0133] In some possible design schemes, the PCI of the terminal device may remain unchanged before and after switching satellites, that is, the PCI of the first satellite and the PCI of the second satellite after switching are the same.

[0134] In one possible design, the first information can be carried in the terminal device's dedicated signaling, including one or more of the following: broadcast messages, radio resource control (RRC) signaling, medium access control (MAC)-control element (CE), and downlink control information (DCI). Alternatively, a portion of the first information, such as the time when the second satellite provides network services to the terminal device, can be carried in the terminal device's dedicated signaling.

[0135] Optionally, dedicated signaling for the terminal equipment can also be used to indicate the time of downlink synchronization.

[0136] Both the first and second satellites provide network services either using a staring mode or a non-staring mode.

[0137] S302, the terminal device determines the first timing advance based on the location of the terminal device and the first information.

[0138] The first timing advance is used to indicate the length of time that is advanced to eliminate the transmission delay of data sent by the terminal device to the second satellite.

[0139] For example, the location of the terminal device can be determined according to existing technology. For instance, the location of the terminal device can be determined by the terminal device based on a global navigation satellite system (GNSS). Alternatively, the location of the terminal device can be measured based on reference signals from a network device providing network services to the terminal device, such as a first satellite.

[0140] A service link refers to the communication link between the terminal device and the satellite. The service link corresponding to the second satellite refers to the communication link between the terminal device and the second satellite.

[0141] For example, the terminal device can determine the position of the second satellite based on its ephemeris information, and determine a first distance between the terminal device and the second satellite based on the terminal device's position and the second satellite's position. Then, based on the first distance and the propagation speed of electromagnetic waves, such as the speed of light, it can determine the timing advance of the service link of the second satellite. Furthermore, it can determine a first timing advance based on the timing advance of the service link of the second satellite. The first distance and the timing advance of the service link satisfy the following relationship: Timing advance of the service link = First distance / Propagation speed of electromagnetic waves; or, Timing advance of the service link = Round-trip time on the service link / 2.

[0142] If the second satellite has some or all base station functions, that is, if the second satellite is a synchronization node, the first timing advance may optionally include the TA of the service link. For example, if the second satellite is satellite 204d, the first timing advance includes the TA of the service link between the terminal equipment and satellite 204d.

[0143] In the case where the second satellite transmits data transparently, the first timing advance may optionally include the timing reference (TA) of the service link of the second satellite and the timing reference (TA) of the feed link of the second satellite.

[0144] For example, if the second satellite is satellite 204a, the first timing advance includes the timing advance (TA) of the service link between the terminal equipment and satellite 204a, and the timing advance (TA) of the power supply link between satellite 204a and network equipment 204.

[0145] The transfer condition (TA) of the feed link of the second satellite can be indicated by the first information. For example, the first information can carry the TA of the feed link of the second satellite. Alternatively, the second satellite can carry the round-trip time (RTD) on the feed link of the second satellite. The TA of the feed link of the second satellite can satisfy the following relationship: TA of the feed link of the second satellite = Round-trip time (RTD) on the feed link of the second satellite / 2.

[0146] The TA of the service link of the second satellite is used to indicate the length of time that the transmission delay of data sent by the terminal device to the second satellite is advanced on the service link of the second satellite. The TA of the feed link of the second satellite is used to indicate the length of time that the transmission delay of data sent by the terminal device to the second satellite is advanced on the feed link of the second satellite.

[0147] This allows for data transmission to satellites with either transparent or non-transparent architectures, improving adaptability.

[0148] based on Figure 3 The provided communication method allows the terminal device to receive first information from the first satellite in advance and determine a first timing advance based on the terminal device's location and the first information. In this way, the terminal device can obtain a timing advance for sending data to the second satellite before satellite switching, avoiding the execution of random access procedures, thereby reducing signaling overhead and transmission delay.

[0149] In one possible design, the first information can also be used to indicate the time when the second satellite will provide network services to the terminal device.

[0150] For example, the time when the second satellite provides network services to the terminal device can be carried in the terminal device's UE-specific signaling, such as RRC signaling, MAC CE, or DCI.

[0151] In this case Figure 3 The provided method may also include S303.

[0152] S303, the terminal device sends data according to the time when the second satellite provides network services to the terminal device and the first timing advance.

[0153] The following will further discuss the S303 in different scenarios.

[0154] If a satellite handover occurs during the transmission of uplink data by the terminal device, and the second satellite begins receiving data from the time when the second satellite provides network services to the terminal device, and the timing advance of the second satellite is greater than the timing advance of the first satellite, the terminal device can transmit data in either method one or method two.

[0155] Method 1, in step S303 above, where the terminal device transmits data based on the time when the second satellite provides network services to the terminal device and the first timing advance, may include: the terminal device obtaining the second timing advance of the first satellite. The terminal device determines the overlapping time period of the first time period and the second time period based on the second timing advance of the first satellite, the time when the second satellite provides network services to the terminal device, and the first timing advance. The first time period is the time period for transmitting the first portion of the first data to the first satellite, and the second time period is the time period for transmitting the second portion of the first data to the second satellite. If the length of the overlapping time period is greater than or equal to a first duration threshold, the terminal device transmits the data corresponding to the first sub-time period from the first portion of the data to the first satellite, and transmits the second portion of the data to the second satellite. The first sub-time period is the time period within the first time period excluding the overlapping time period. The terminal device transmits the first portion of the data to the first satellite and transmits the data corresponding to the second sub-time period from the second portion of the data to the second satellite. The second sub-time period is the time period within the second time period excluding the overlapping time period.

[0156] In other words, when the first time period overlaps with the second time period, some data from the first part of the data that falls within the overlapping time period can be discarded, or some data from the second part of the data that falls within the overlapping time period can be discarded.

[0157] The first data is the data that the terminal device needs to transmit. Without satellite handover, the timing advance for different parts of the first data transmitted by the terminal device is the same. For example... Figure 4 As shown in (a), assuming that the first data is continuous in time, the time period for the first satellite to receive the first data without switching satellites is the time period between T0-2ms and T0+2ms. The second timing advance of the first satellite is 2 milliseconds (ms). Then the terminal device sends the first data in the time period between T0-4ms and T0.

[0158] In this embodiment, when a satellite handover occurs, the first and second portions of the first data can be determined based on the handover time. For example, if the terminal device switches satellites at time T0 and the second timing advance is 2ms, then the first portion of the first data refers to the data in the first data that is located before T0-2ms without a satellite handover. The second portion of the first data refers to the data in the first data that is located after T0-2ms without a satellite handover.

[0159] The first duration threshold can be 10 orthogonal frequency division multiplexing (OFDM) symbols or 10 sampling points.

[0160] Furthermore, the principle for obtaining the second timing advance can refer to the implementation principle of timing advance in the existing technology, which will not be elaborated here.

[0161] For example, if the start time of the second satellite providing network services to the terminal device is T0, then the time period for the terminal device to send the first part of data to the first satellite is from T0 - second timing advance - duration of the first data to T0 - second timing advance, and the time period for the terminal device to send the second part of data to the second satellite is from T0 - first timing advance to T0 - first timing advance + duration of the second data. The following example using the first and second satellites illustrates the above method one.

[0162] like Figure 4 As shown in (b), assuming the terminal device performs a satellite handover at time T0, the first timing advance of the first satellite is 2ms, the second timing advance of the second satellite is 2.5ms, and the total duration of the data to be transmitted by the terminal device is 5ms, if the length of the first time period is 2ms and the length of the second time period is 2ms, then the first time period is the period between T0-2ms-2ms and T0-2ms, i.e., the period between T0-4ms and T-2ms. The second time period is the period between T0-2.5ms and T0-2.5ms+2ms, i.e., the period between T0-2.5ms and T0-0.5ms. In this case, the period between T0-2.5ms and T0-2ms is an overlapping period. Among them, the period between T0-4ms and T0-2.5ms is the first sub-period. The period between T0-2ms and T0-0.5ms is the second sub-period. To improve data transmission success rate and reliability, only one data segment can be transmitted within an overlapping time period. In this case, according to Method 1, the terminal device can transmit the data corresponding to the time period from T0-4ms to T0-2.5ms in the first part of the data to the first satellite, and the second part of the data to the second satellite. Alternatively, the terminal device can transmit the first part of the data to the first satellite, and the data corresponding to the time period from T0-2ms to T0-0.5ms in the second part of the data to the second satellite.

[0163] Using the first method described above can avoid data overlap, reduce interference between data, and improve the transmission success rate.

[0164] If a satellite handover occurs during the transmission of uplink data by the terminal device, the second satellite will start receiving data from the time when the second satellite provides network services to the terminal device. The timing advance of the second satellite is less than or equal to the timing advance of the first satellite. In this case, the terminal device can transmit data in the following manner: Method 2.

[0165] Method 2: The terminal device sends first data to the first satellite at the end of a second timing advance interval before the start time when the second satellite provides network services to the terminal device, and sends second data to the second satellite at the first timing advance interval.

[0166] Taking the data sent by the terminal device as the first data as an example, such as Figure 4 As shown in (c), the satellite switching time is T0. If the length of the first time period is 2ms, then the length of the second time period is 2ms. The second timing advance is 2.5ms, the first timing advance is 2ms, the first time period is the period between T0-4.5ms and T0-2.5ms, and the second time period is the period between T0-2ms and T0. In this case, during the period between T0-4.5ms and T0-2.5ms, the terminal device sends the first part of the data to the first satellite, and during the period between T0-2ms and T0, the terminal device sends the second part of the data to the second satellite.

[0167] Alternatively, the second satellite may receive data at a time after the start of the second satellite's provision of network services to the terminal device, with a certain time interval between the start of the second satellite's provision of network services to the terminal device. In this case, optionally, Figure 3 The provided communication method may further include: a first satellite transmitting second information. Correspondingly, a terminal device receives the second information. The second information indicates a third time period. The length of the third time period is the interval between the moment the first satellite stops transmitting information or the moment the terminal device's scheduling waiting period ends, and the start moment the second satellite receives uplink data from the terminal device. At this time, the terminal device transmits data according to the time the second satellite provides network services to the terminal device and a first timing advance, including: the terminal device transmitting first uplink data according to the third time period, the time the second satellite provides network services to the terminal device, and the first timing advance. The first uplink data may be the second part of the data in Method 1 or Method 2 described above, or scheduling information transmitted by the first satellite, such as uplink data scheduled by DCI, or other uplink data that the terminal device needs to transmit to the second satellite.

[0168] The second information can indicate the third time period directly. For example, the second information can carry the start and end times of the third time period. Alternatively, the second information can indicate the third time period indirectly. For example, the second information can carry the length of the third time period. Furthermore, if the third time period is related to the first and second times, the second information can carry the first and second times. Here, the first time is the moment when the first satellite stops transmitting scheduling information. The second time is the start time when the second satellite begins receiving uplink data from the terminal device. In this case, after obtaining the first and second times, the terminal device can determine the third time period based on the first and second times, the first timing advance, and the second timing advance. The start time of the third time period can be the end time when the terminal device finishes transmitting the first portion of data to the first satellite. The end time of the third time period satisfies the following relationship: End time of the third time period = End time when the terminal device finishes transmitting the first portion of data to the first satellite + Length of the third time period + First timing advance - Second timing advance.

[0169] For example, if the terminal device switches satellites during uplink data transmission, the length of the third time period can be related to the time when the first satellite finishes receiving data from the terminal device and the time when the second satellite begins receiving data from the terminal device. In this case, the terminal device can transmit data in the following manner (method three).

[0170] Method 3: The terminal device sends data based on the time when the second satellite provides network services to the terminal device and the first timing advance. This may include: the terminal device sending a first portion of the first data to the first satellite during a first time period, and the terminal device sending a second portion of the first data to the second satellite during a second time period. The start time of the second time period is the time interval preceding the start time of the third time period, equal to the first timing advance.

[0171] like Figure 5 As shown, taking the first data as an example, assuming that the end time of the first part of the data sent by the terminal device to the first satellite is T1, and the length of the third time period is 2ms, then the third time period is the time period between T1 and T1+2ms. The first timing advance is 0.5ms, so the time when the terminal device starts sending the second part of the data to the second satellite can be T1+2ms-0.5ms, that is, T1+1.5ms.

[0172] Furthermore, if the overlap between the second and third time periods is greater than or equal to the second duration threshold, then the terminal device sending the second portion of the first data to the second satellite during the second time period may include: the terminal device sending data from the second data corresponding to the third sub-time period to the second satellite during the third sub-time period. In other words, the terminal device may discard the data from the second portion of the second data that falls within the third time period.

[0173] The second duration threshold can be 10 OFDM symbols or 10 sampling points.

[0174] In Method 3, if the first timing advance is greater than the second timing advance, then the length of the third time period is greater than or equal to the first timing advance.

[0175] Alternatively, the third time period can be the duration used by the terminal device for downlink synchronization. In this case, the terminal device can send data based on the actual duration used for downlink synchronization and the first timing advance. See Methods Four and Five below for details.

[0176] Method 4: If the terminal device can complete downlink synchronization within the time length of the third time period minus the first timing advance, then the terminal device can use the downlink synchronization time to send data to the second satellite. The following combines... Figure 6 illustrate.

[0177] like Figure 6 As shown, taking the first timing advance as greater than the second timing advance as an example, if the downlink synchronization of the terminal device is performed after sending the first part of the data to the first satellite, and the third time period used by the terminal device for downlink synchronization is the time period between time T2 and time T2+2ms, the length of the third time period is 2ms, the actual time length used by the terminal device for downlink synchronization is 1ms, and the first timing advance is 0.5ms, then the terminal device can send the first part of the data to the first satellite in the first time period, and the terminal device can send the second part of the first data to the second satellite in the second time period.

[0178] Furthermore, if the overlap between the second and third time periods is greater than or equal to the third duration threshold, then the terminal device sending the second portion of the first data to the second satellite during the second time period may include: the terminal device sending data from the second data corresponding to the third sub-time period to the second satellite during the third sub-time period. In other words, the terminal device may discard the data from the second portion of the second data that falls within the third time period.

[0179] The third duration threshold can be 10 OFDM symbols or 10 sampling points.

[0180] Method 5: If downlink synchronization of the terminal device occurs after sending the first part of the data to the first satellite, and the terminal device cannot complete downlink synchronization within the time length of the third time period minus the first timing advance, then if the first timing advance is less than the fourth duration threshold, the data corresponding to the overlapping time period in the second part of the data can be discarded, and the data corresponding to the third sub-time period in the second part of the data can be sent to the second satellite. The third sub-time period is the time period in the second time period excluding the overlapping time period. The following is combined with... Figure 7 Explanation. For example... Figure 7 As shown, the actual downlink synchronization time of the terminal device is 1.7ms, and the first timing advance is 0.5ms. Therefore, the data in the second data that corresponds to the time period between T2+1.7ms and T2+2.5ms (corresponding to the overlapping time period) can be discarded, and only the data in the second part of the data that corresponds to the third sub-time period can be sent.

[0181] The fourth duration threshold can be 10 OFDM symbols or 10 sampling points.

[0182] Alternatively, for example, if the data sent by the terminal device to the second satellite is scheduled by the first satellite, then the third time period is the interval between the first moment when the first satellite stops sending scheduling information and the second moment when the second satellite starts receiving data from the terminal device (the second moment). For example, the scheduling information can be information used for resource scheduling, such as DCI. In this case, the terminal device can transmit data in the following manner (method six).

[0183] Method six, where the terminal device sends data based on the time when the second satellite provides network services to the terminal device and the first timing advance, may include: the terminal device sending first uplink data based on a third time period, the time when the second satellite provides network services to the terminal device and the first timing advance.

[0184] Furthermore, the transmission of the first uplink data according to the third time period, the time when the second satellite provides network services to the terminal device, and the first timing advance includes: if the transmission time period of the first uplink data overlaps with the third time period, then the data corresponding to the third sub-time period in the first uplink data is transmitted to the second satellite. In this case, the third sub-time period is the time period in the transmission time period excluding the overlapping time period.

[0185] The transmission time period refers to the time during which the terminal device transmits data to the second satellite. The principle behind the transmission time period can be found in the description of the second time period. When the first data is the second part of either Mode 1 or Mode 2, the transmission time period can be the second time period.

[0186] For details on the implementation principles of Method Six, please refer to the implementation principles of Method Four or Method Five; they will not be elaborated upon here.

[0187] This delays the time it takes for the second satellite to receive data, thereby avoiding data overlap between terminal devices and different satellites and improving communication efficiency.

[0188] It is understood that, when the first timing advance is less than or equal to the second timing advance, in any of the scenarios in methods four to six, the terminal device sends data based on the time when the second satellite provides network services to the terminal device and the first timing advance. This may include the first device sending a first portion of data to the first satellite in a first time period and sending a second portion of data to the second satellite in a second time period. For example, the second portion of data may be sent after a third time period at an interval of a first duration. Wherein, the first duration = second timing advance - first timing advance. Figure 8 For example, if the terminal device sends the first part of the data to the first satellite and the second part of the data to the second satellite, and the third time period is the time period between T2 and T2+2ms, the first timing advance is 1ms, the second timing advance is 0.5ms, and the terminal device ends sending the first part of the data at time T2, then the terminal device starts sending the second part of the data to the second satellite at time T2+2.5ms.

[0189] In some possible scenarios, the first satellite configures a scheduling waiting period for the terminal device. That is, after receiving the DCI, the terminal device needs to wait for a period of time to transmit data. In this case, the time when the terminal device sends uplink data to the second satellite is related to the length of the scheduling waiting period and the third time period.

[0190] For example, the time when the terminal device sends uplink data to the second satellite = the time when DCI reception ends + the length of the scheduling waiting period + the length of the third time period.

[0191] like Figure 9 As shown, with the end of DCI reception as T3, the length of the scheduling waiting period is 1.5ms, the length of the third period is 1ms, the duration of the scheduled data is 2ms, and the first timing advance is 0.5ms, then the third period is from T3+2ms to T3+4ms, and the time when the terminal device starts sending the scheduled data to the second satellite is T3+2ms.

[0192] In one possible design scheme, Figure 3 The communication method shown may further include: a first satellite transmitting third information; and a terminal device acquiring the third information accordingly.

[0193] The third information is used to indicate the second and third durations. The second duration is the time for which the scheduling data waits, and the third duration is the time reserved for downlink synchronization.

[0194] For example, if the physical downlink shared channel (PDSCH) or physical uplink control channel (PUCCH) is scheduled through DCI, the second duration is the time length between the end time of the first satellite transmitting the first data and the time when the first satellite starts transmitting the PDSCH corresponding to the DCI, or the time length between the end time of the first satellite transmitting the first data and the time when the second satellite starts receiving the PUCCH scheduled by the DCI.

[0195] If the second duration is less than the third duration, the terminal device will perform downlink synchronization during the third duration following the second duration. In this case, the terminal device can send uplink data using either method four or method six described above.

[0196] If the second duration is greater than or equal to the third duration, the terminal device will perform downlink synchronization within the second duration. In this case, a timing advance can be made based on the end time of the second duration to send data to the second satellite. For the specific implementation principle, please refer to Method 4 or Method 5, which will not be elaborated here.

[0197] In this way, the downlink synchronization process and the waiting time for transmitting data to the second satellite can be taken into account.

[0198] Furthermore, for downlink data transmission, the data transmitted by the first and second satellites can be coordinated by network equipment or satellites with some or all of the network equipment's functions. In this case, the frame numbers of the data transmitted by the first satellite and the data transmitted by the second satellite are consecutive.

[0199] In this case, the implementation principle of S303 refers to the implementation principle of any one of the above methods four to six, and will not be repeated here.

[0200] In this way, the terminal device can transmit data according to the first timing advance, thereby reducing signaling overhead and transmission latency.

[0201] In addition, optionally, Figure 3 The method shown may also include: a first satellite transmitting fourth information; and a terminal device receiving the fourth information accordingly.

[0202] The fourth information is used to indicate the start time of downlink synchronization by the terminal device. For example, the fourth information can indicate the start time of downlink synchronization by indicating the number of times the terminal device sends uplink data. For instance, if the fourth information indicates that the terminal device sends uplink data for the fourth time, the terminal device can perform downlink synchronization after the fourth repetition. Alternatively, the fourth information can indicate the number of subframes following the fourth information to indicate the start time of downlink synchronization. For instance, if the fourth information indicates three subframes, the terminal device will perform downlink synchronization three subframes after receiving the fourth information.

[0203] In addition, when PCI switches, the terminal device needs to use the new PCI to scramble the uplink data.

[0204] The above combination Figures 3-9 The communication method provided in the embodiments of this application is described in detail below. Figures 10-11 This document describes in detail the communication apparatus used to perform the communication method provided in the embodiments of this application.

[0205] For example, Figure 10 This is a schematic diagram of the structure of the communication device provided in the embodiments of this application. Figure 1 .like Figure 10 As shown, the communication device 1000 includes a processing module 1001 and a transceiver module 1002. For ease of explanation, Figure 10 Only the main components of the communication device are shown.

[0206] In some embodiments, the communication device 1000 may be adapted to Figure 2 In the communication system shown, the execution Figure 3 The function of the terminal device in the communication method shown.

[0207] The communication device 1000 is used to receive first information from a first satellite. The first information is used to indicate the ephemeris information of a second satellite. The processing module 1001 is used to determine a first timing advance based on the position of the communication device 1000 and the first information. The first timing advance indicates the length of time advanced to eliminate the transmission delay of data sent by the communication device 1000 to the second satellite.

[0208] In one possible design, the first satellite is the one currently providing network services to the communication device 1000, and the second satellite is the one that the communication device 1000 will switch to.

[0209] In one possible design, the first timing advance includes the timing advance TA of the service link of the second satellite. Alternatively, the first timing advance includes the TA of the service link of the second satellite and the TA of the feeder link. The TA of the service link of the second satellite indicates the time length by which the transmission delay of data sent by the communication device 1000 to the second satellite on the service link of the second satellite is eliminated, and the TA of the feeder link indicates the time length by which the transmission delay of data sent by the communication device 1000 to the second satellite on the feeder link of the second satellite is eliminated.

[0210] Optionally, the first information is also used to indicate the TA of the feed link of the second satellite.

[0211] In one possible design, the first information is also used to indicate the time when the second satellite provides network services to the communication device 1000, and the communication device 1000 is also used to transmit data according to the second satellite providing network services to the communication device 1000 and the first timing advance.

[0212] Optionally, the communication device 1000 is specifically used to obtain a second timing advance of the first satellite. Based on the second timing advance, the time when the second satellite provides network services to the communication device 1000, and the first timing advance, the overlapping time period of the first time period and the second time period is determined. The first time period is the time period for transmitting a first portion of the first data to the first satellite, and the second time period is the time period for transmitting a second portion of the first data to the second satellite. If the length of the overlapping time period is greater than or equal to a first duration threshold, the communication device 1000 transmits the data corresponding to the first sub-time period from the first portion of the data to the first satellite, and transmits the second portion of the data to the second satellite; the first sub-time period is the time period within the first time period excluding the overlapping time period. Alternatively, the communication device 1000 transmits the first portion of the data to the first satellite, and transmits the data corresponding to the second sub-time period from the second portion of the data to the second satellite. The second sub-time period is the time period within the second time period excluding the overlapping time period. The second timing advance is used to indicate the length of time advanced to eliminate the transmission delay of the data transmitted by the communication device 1000 to the first satellite.

[0213] Alternatively, the communication device 1000 may further be configured to receive second information from the first satellite. The second information indicates a third time period, the length of which is the interval between the moment the first satellite stops transmitting information or the moment the communication device 1000 ends its scheduled waiting period, and the moment the second satellite begins receiving uplink data from the communication device 1000. Specifically, the communication device 1000 is configured to send first uplink data according to the third time period, the time the second satellite provides network services to the communication device 1000, and a first timing advance. The duration between the moment the communication device 1000 begins sending fifth data to the second satellite and the second moment is less than or equal to the first timing advance.

[0214] Furthermore, the communication device 1000 is specifically used to: when there is an overlap between the transmission time period of the first uplink data and the third time period, transmit data corresponding to the third sub-time period in the first uplink data to the second satellite, wherein the third sub-time period is the time period in the transmission time period excluding the overlapping time period.

[0215] In one possible design, the communication device 1000 is further configured to receive third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the communication device 1000 and the second satellite. If the second duration is less than the third duration, the communication device 1000 performs downlink synchronization with the second satellite during the third duration following the second duration.

[0216] In one possible design, the communication device 1000 is further configured to receive third information from the first satellite. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the communication device 1000 and the second satellite. If the second duration is greater than or equal to the third duration, the communication device 1000 performs downlink synchronization with the second satellite within the second duration.

[0217] In one possible design, the communication device 1000 is further configured to receive a synchronization signal and a broadcast channel block (SSB) from the second satellite. The SSB indicates the Physical Cell Identifier (PCI) of the second satellite. The processing module 1001 is further configured to obtain the PCI of the second satellite based on its SSB.

[0218] In one possible design, the first information can also be used to indicate the PCI of the second satellite.

[0219] In one possible design, the first information includes dedicated signaling for the communication device 1000, and the time for the second satellite to provide network services to the communication device 1000 can be carried in one or more of the following: RRC signaling, MAC CE, or DCI.

[0220] Optionally, the downlink synchronization time of the communication device 1000 is carried in one or more of the following: RRC signaling, MAC CE, or DCI.

[0221] In other embodiments, the communication device 1000 may be adapted to Figure 2 In the communication system shown, the execution Figure 3 The function of the first satellite in the communication method shown.

[0222] The processing module 1001 is used to determine the first information. The communication device 1000 is used to send the first information to the terminal device. The first information is used to indicate the ephemeris information of the second satellite.

[0223] In one possible design, the communication device 1000 is the satellite currently providing network services to the terminal device, and the second satellite is the satellite that the terminal device is about to switch to.

[0224] In one possible design, the communication device 1000 is further configured to send second information to the terminal device. The second information indicates a third time period, the length of which is the interval between the moment the communication device 1000 transmits information or the end of the terminal device's scheduling waiting period and the start time of the second satellite receiving uplink data from the terminal device.

[0225] In one possible design, the first information can also be used to indicate the PCI of the second satellite.

[0226] In one possible design, the communication device 1000 is further configured to send third information to the terminal device. This third information indicates a second duration for which scheduling data is awaited, and a third duration reserved for downlink synchronization between the terminal device and the second satellite.

[0227] Optionally, the transceiver module 1002 may include a receiving module and a transmitting module. The transceiver module 1002 is used to implement the transmitting and receiving functions of the communication device 1000.

[0228] Optionally, the communication device 1000 may also include a storage module ( Figure 10 (Not shown in the image), this storage module stores programs or instructions. When the processing module 1001 executes the program or instructions, the communication device 1000 can perform [operations / functions]. Figure 3 The function of the first satellite in the communication method shown.

[0229] It should be understood that the processing module 1001 involved in the communication device 1000 can be implemented by a processor or processor-related circuit components, and can be a processor or processing unit; the transceiver module 1002 can be implemented by a transceiver or transceiver-related circuit components, and can be a transceiver or transceiver unit.

[0230] Communication device 1000 can be Figure 2 The first satellite shown may also be a chip (system) or other component or assembly disposed in the aforementioned satellite, or a device containing the first satellite. This application embodiment does not limit this.

[0231] Furthermore, the technical effects of the communication device 1000 can be referred to separately. Figure 3 The technical effects of any of the communication methods shown in the examples are not elaborated here.

[0232] For example, Figure 11 Schematic diagram of the communication device provided in the embodiments of this application Figure 2 The communication device can be a terminal device or a network device, or it can be a chip (system) or other component or assembly that can be installed in the terminal device or network device. For example... Figure 11 As shown, the communication device 1100 may include a processor 1101. Optionally, the communication device 1100 may also include a memory 1102 and / or a transceiver 1103. The processor 1101 is coupled to the memory 1102 and the transceiver 1103, for example, they can be connected via a communication bus.

[0233] The following is combined with Figure 11 A detailed description of each component of the communication device 1100 is provided below: The processor 1101 is the control center of the communication device 1100. It can be a single processor or a collective term for multiple processing elements. For example, the processor 1101 can be one or more central processing units (CPUs), application-specific integrated circuits (ASICs), or one or more integrated circuits configured to implement the embodiments of this application, such as one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs).

[0234] Optionally, the processor 1101 can perform various functions of the communication device 1100 by running or executing software programs stored in the memory 1102 and calling data stored in the memory 1102.

[0235] In a specific implementation, as one example, the processor 1101 may include one or more CPUs, for example... Figure 11 CPU0 and CPU1 are shown in the diagram.

[0236] In a specific implementation, as one example, the communication device 1100 may also include multiple processors, for example... Figure 11 The processors 1101 and 1104 shown are illustrated. Each of these processors can be a single-core processor or a multi-core processor. Here, "processor" can refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0237] The memory 1102 is used to store the software program that executes the solution of this application, and is controlled by the processor 1101 to execute it. The specific implementation method can be referred to the above method embodiment, and will not be repeated here.

[0238] Optionally, the memory 1102 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. The memory 1102 may be integrated with the processor 1101 or may exist independently, and may be connected via the interface circuit of the communication device 1100. Figure 11 (Not shown in the image) is coupled to processor 1101, and this embodiment of the application does not specifically limit this.

[0239] Transceiver 1103 is used for communication with other communication devices. For example, if communication device 1100 is a terminal device, transceiver 1103 can be used to communicate with a network device or with another terminal device. As another example, if communication device 1100 is a network device, transceiver 1103 can be used to communicate with a terminal device or with another network device.

[0240] Optionally, transceiver 1103 may include a receiver and a transmitter. Figure 11 (Not shown separately). The receiver is used to implement the receiving function, and the transmitter is used to implement the transmitting function.

[0241] Optionally, the transceiver 1103 can be integrated with the processor 1101, or it can exist independently and be connected via the interface circuit of the communication device 1100. Figure 11 (Not shown in the image) is coupled to processor 1101, and this embodiment of the application does not specifically limit this.

[0242] Figure 11 The structure of the communication device 1100 shown does not constitute a limitation on the communication device. Actual communication devices may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0243] Furthermore, the technical effects of the communication device 1100 can be referred to the technical effects of the communication method described in the above method embodiments, and will not be repeated here.

[0244] It should be understood that the processor in the embodiments of this application can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0245] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0246] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0247] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0248] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0249] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0250] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0251] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0252] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0253] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0254] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0255] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0256] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, The method includes: Receive first information from a first satellite; wherein the first information is used to indicate the ephemeris information of a second satellite and to indicate the time when the second satellite provides network services to the terminal device; A first timing advance is determined based on the location of the terminal device and the first information; wherein, the first timing advance is used to indicate the length of time that is advanced to eliminate the transmission delay of the data sent by the terminal device to the second satellite; Data is transmitted according to the time when the second satellite provides network services to the terminal device and the first timing advance. The step of transmitting data according to the time when the second satellite provides network services to the terminal device and the first timing advance includes: Obtain a second timing advance; wherein the second timing advance is used to indicate the length of time that is advanced to eliminate the transmission delay of the data sent by the terminal device to the first satellite; Based on the second timing advance, the time when the second satellite provides network services to the terminal device, and the first timing advance, the overlapping time period of the first time period and the second time period is determined; wherein, the first time period is the time period for sending the first part of the first data to the first satellite, and the second time period is the time period for sending the second part of the first data to the second satellite; If the length of the overlapping time period is greater than or equal to a first duration threshold, then the data corresponding to the first sub-time period in the first part of the data is sent to the first satellite, and the second part of the data is sent to the second satellite; the first sub-time period is the time period in the first time period excluding the overlapping time period; or, the first part of the data is sent to the first satellite, and the data corresponding to the second sub-time period in the second part of the data is sent to the second satellite; the second sub-time period is the time period in the second time period excluding the overlapping time period.

2. The method according to claim 1, characterized in that, The first satellite is the one currently providing network services to the terminal device, and the second satellite is the one that the terminal device is about to switch to.

3. The method according to claim 1 or 2, characterized in that, The first timing advance includes the timing advance TA of the service link of the second satellite; or, the first timing advance includes the TA of the service link of the second satellite and the TA of the power supply link; wherein, the TA of the service link of the second satellite is used to indicate the time length by which the transmission delay of the data sent by the terminal device to the second satellite on the service link of the second satellite is eliminated, and the TA of the power supply link is used to indicate the time length by which the transmission delay of the data sent by the terminal device to the second satellite on the power supply link of the second satellite is eliminated.

4. The method according to claim 3, characterized in that, The first information is also used to indicate the TA of the feed link of the second satellite.

5. The method according to claim 1 or 2, characterized in that, The method further includes: Receive third information from the first satellite; wherein the third information is used to indicate a second duration for which scheduling data is waiting, and a third duration reserved for the terminal device to perform downlink synchronization with the second satellite; If the second duration is less than the third duration, then downlink synchronization with the second satellite will be performed within the third duration after waiting for the second duration.

6. The method according to claim 1 or 2, characterized in that, The method further includes: Receive third information from the first satellite; wherein the third information is used to indicate a second duration for which scheduling data is waiting, and a third duration reserved for the terminal device to perform downlink synchronization with the second satellite; If the second duration is greater than or equal to the third duration, then downlink synchronization with the second satellite will be performed within the second duration.

7. The method according to claim 1 or 2, characterized in that, The method further includes: Receive synchronization signals and broadcast channel blocks (SSBs) from the second satellite; wherein the SSBs are used to indicate the physical cell identifier (PCI) of the second satellite; Obtain the PCI of the second satellite based on the SSB of the second satellite.

8. The method according to claim 1 or 2, characterized in that, The first information is also used to indicate the PCI of the second satellite.

9. The method according to claim 1 or 2, characterized in that, The time that the second satellite provides network services to the terminal device is carried in one or more of the following on the terminal device: RRC signaling, MAC CE, or DCI.

10. The method according to claim 1 or 2, characterized in that, The downlink synchronization time of the terminal device is carried in one or more of the following: RRC signaling, MAC CE, or DCI.

11. A communication method, characterized in that, The method includes: The first satellite determines the first information; The first satellite sends first information to the terminal device; wherein the first information is used to indicate the ephemeris information of the second satellite and to indicate the time when the second satellite provides network services to the terminal device, so as to determine a first timing advance based on the location of the terminal device and the first information; wherein the first timing advance is used to indicate: the length of time advanced to eliminate the transmission delay of the data sent by the terminal device to the second satellite; and to enable the terminal device to send data according to the time when the second satellite provides network services to the terminal device and the first timing advance; The step of transmitting data according to the time when the second satellite provides network services to the terminal device and the first timing advance includes: Obtain a second timing advance; wherein the second timing advance is used to indicate the length of time that is advanced to eliminate the transmission delay of the data sent by the terminal device to the first satellite; Based on the second timing advance, the time when the second satellite provides network services to the terminal device, and the first timing advance, the overlapping time period of the first time period and the second time period is determined; wherein, the first time period is the time period for sending the first part of the first data to the first satellite, and the second time period is the time period for sending the second part of the first data to the second satellite; If the length of the overlapping time period is greater than or equal to a first duration threshold, then the data corresponding to the first sub-time period in the first part of the data is sent to the first satellite, and the second part of the data is sent to the second satellite; the first sub-time period is the time period in the first time period excluding the overlapping time period; or, the first part of the data is sent to the first satellite, and the data corresponding to the second sub-time period in the second part of the data is sent to the second satellite; the second sub-time period is the time period in the second time period excluding the overlapping time period.

12. The method according to claim 11, characterized in that, The first satellite is the one currently providing network services to the terminal device, and the second satellite is the one that the terminal device is about to switch to.

13. The method according to claim 11 or 12, characterized in that, The first information is also used to indicate the PCI of the second satellite.

14. The method according to claim 11 or 12, characterized in that, The method includes: Send a third message to the terminal device; wherein the third message is used to indicate a second duration for which the scheduling data is waiting, and a third duration reserved for the terminal device to perform downlink synchronization with the second satellite.

15. A communication device, characterized in that, The communication device is used to perform the communication method as described in any one of claims 1-10.

16. A communication device, characterized in that, The communication device is used to perform the communication method as described in any one of claims 11-14.

17. A communication device, characterized in that, include: Processor, the processor being coupled to memory; The processor is configured to execute a computer program stored in the memory, so that the communication device performs the communication method as described in any one of claims 1-14.

18. The apparatus according to claim 17, characterized in that, The communication device also includes a transceiver, which is used for information exchange between the communication device and other communication devices.

19. A communication device, characterized in that, include: Processor and interface circuits; among which, The interface circuit is used to receive code instructions and transmit them to the processor; The processor is used to run the code instructions to perform the method as described in any one of claims 1-14.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instructions that, when executed on a computer, cause the computer to perform the communication method as described in any one of claims 1-14.

21. A computer program product, characterized in that, The computer program product includes: a computer program or instructions that, when executed on a computer, cause the computer to perform the communication method as described in any one of claims 1-14.

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