Communication method and device

Abstract

Disclosed are a communication method and device, the method comprising: a terminal receiving first indication information from a first cell corresponding to a first satellite, the first indication information being used for indicating the terminal to perform uplink synchronization with a second satellite by not triggering a random access process. And after the terminal is in the coverage range of the second satellite, if the first SSB and the second SSB are the same, uplink synchronization with the second satellite is carried out by not triggering a random access process, the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite. Through the method, after the terminal is in the coverage range of the second satellite, the terminal can perform uplink synchronization with the second satellite by not triggering the random access process, so that the efficiency of cross-satellite switching of the terminal can be improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0002] In non-terrestrial networks (NTN), as the satellite moves, the satellite that can provide services to the terminal may change. For example, satellite 1 provides services to terminal 1 to terminal M, where M is a positive integer. As the satellite moves, terminal 1 to terminal M changes from being within the coverage of satellite 1 to being within the coverage of satellite 2, and thus needs to switch to satellite 2, which provides services to terminal 1 to terminal M. In this way, a large number of terminals may need to switch from one satellite to another in a short period of time. How to improve the efficiency of terminals when switching across satellites requires further research. Summary of the invention

[0003] The present application provides a communication method and device for improving the efficiency of a terminal during inter-satellite switching.

[0004] In the first aspect, an embodiment of the present application provides a communication method, which can be applied to a first device, and the first device can be a terminal or a module in the terminal (such as a circuit, a chip, a chip system or a processor), and can also be a logical node, a logical module or software that can realize all or part of the terminal functions. The following is an explanation using the first device as an example of a terminal. The method may include: the terminal may receive first indication information from a first cell corresponding to a first satellite, and the first indication information is used to instruct the terminal to perform uplink synchronization with a second satellite without triggering a random access process. After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, the terminal may perform uplink synchronization with the second satellite without triggering a random access process. Among them, the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite.

[0005] Through this method, after the terminal is in the coverage of the second satellite, the terminal can perform uplink synchronization with the second satellite without triggering a random access process, thereby improving the efficiency of the terminal when switching across satellites. Moreover, in this method, when the first SSB and the second SSB are the same, the terminal can perform uplink synchronization with the second satellite without triggering a random access process, so that the terminal can receive a message from the second satellite through the beam corresponding to the second SSB and successfully switch to the second satellite.

[0006] In one possible design, after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is greater than the first threshold, the terminal can perform uplink synchronization with the second satellite by not triggering a random access process. In this design, after the terminal is in the coverage of the second satellite, the terminal can perform uplink synchronization with the second satellite by not triggering a random access process, thereby improving the efficiency of the terminal when switching across satellites. Moreover, in this design, when the first SSB and the second SSB are the same, and the signal quality of the second SSB is greater than the first threshold, the terminal performs uplink synchronization with the second satellite by not triggering a random access process, thereby enabling the terminal to receive a message from the second satellite and successfully switch to the second satellite.

[0007] In one possible design, the method further includes: after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, the terminal can perform uplink synchronization with the second satellite through a random access process. Through this design, it is possible to avoid or reduce the terminal's inability to receive messages from the second satellite when performing uplink synchronization with the second satellite without triggering the random access process, thereby enabling the terminal to receive messages from the second satellite, so that the terminal can successfully switch to the second satellite.

[0008] In one possible design, the method further includes: the terminal may receive resource configuration information from the first cell or the second cell corresponding to the second satellite, and the resource configuration information is used to configure uplink resources. After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, the terminal may send a message to the second cell through the uplink resources. In this design, when the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, the terminal may send a message to the second cell through the uplink resources configured by the resource configuration information, thereby reducing the delay in sending the message to the second cell.

[0009] In one possible design, the method further includes: after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, the terminal may perform uplink synchronization with the second satellite through a random access process. In this design, when the first SSB and the second SSB are different, the terminal may perform uplink synchronization with the second satellite by triggering a random access process, thereby avoiding the terminal being unable to receive a message from the second satellite when performing uplink synchronization with the second satellite without triggering the random access process, thereby enabling the terminal to receive a message from the second satellite and successfully switch to the second satellite.

[0010] In one possible design, the method further includes: the terminal may receive resource configuration information from the first cell or the second cell corresponding to the second satellite, and the resource configuration information is used to configure uplink resources. After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, the terminal may send a message to the second cell through the uplink resources. In this design, when the first SSB and the second SSB are different, the terminal may send a message to the second cell through the uplink resources configured by the resource configuration information, thereby reducing the delay in sending the message to the second cell.

[0011] In one possible design, the method further includes: the terminal may send information indicating the second SSB to the second cell through the uplink resources configured by the resource configuration information. In this way, the terminal may notify the second cell of the second SSB so that the second cell communicates with the terminal using the second SSB.

[0012] Optionally, the cell identifier of the second cell corresponding to the second satellite is the same as or different from that of the first cell.

[0013] In the second aspect, an embodiment of the present application provides a communication method, which can be applied to a first device, and the first device can be a terminal or a module in the terminal (such as a circuit, a chip, a chip system or a processor), and can also be a logical node, a logical module or software that can realize all or part of the terminal functions. The following is an explanation using the first device as a terminal as an example. The method may include: the terminal determines the difference between the first propagation delay and the second propagation delay. Among them, the first propagation delay is the propagation delay of the service link between the terminal and the first cell corresponding to the first satellite, the second propagation delay is the propagation delay of the service link between the terminal and the second cell corresponding to the second satellite, the first satellite is the satellite that provides services to the terminal before the terminal switches, and the second satellite is the satellite that provides services to the terminal after the terminal switches. When the difference is greater than the second threshold, the terminal may send a second indication message, and the second indication message is used to indicate the reconfiguration of uplink resources for the terminal.

[0014] Through this method, when the difference between the first propagation delay and the second propagation delay is greater than the second threshold, the terminal can send the second indication information, and the second indication information can be used to indicate the reconfiguration of uplink resources for the terminal. The first propagation delay is related to the first satellite that provides services to the terminal before the terminal switches, and the second propagation delay is related to the second satellite that provides services to the terminal after the terminal switches. In this way, in the cross-satellite switching scenario, the access network device can reconfigure uplink resources for the terminal, thereby avoiding or reducing data conflicts generated when the terminal performs cross-satellite switching.

[0015] In one possible design, the second indication information includes a difference value. In this way, the access network device can reconfigure uplink resources for the terminal according to the difference value, thereby avoiding data conflicts generated when the terminal performs cross-satellite switching.

[0016] In a possible design, the terminal can predict the difference between the first propagation delay and the second propagation delay at at least one of the following moments: the moment when the first satellite stops providing services for the terminal, the moment when the second satellite starts providing services for the terminal, and the moment when the terminal accesses the second satellite. This design can reduce the amount of calculation of the terminal and reduce the energy consumption of the terminal.

[0017] In a third aspect, an embodiment of the present application provides a communication method, which can be applied to a second device, and the second device can be an access network device or a module in the access network device (such as a circuit, a chip, a chip system or a processor), and can also be a logical node, a logical module or software that can realize all or part of the functions of the access network device. The following is an example of the second device being an access network device. The method may include: the access network device receives a second indication information sent by the terminal when the difference between the first propagation delay and the second propagation delay is greater than the second threshold. Among them, the second indication information is used to indicate the reconfiguration of uplink resources for the terminal, the first propagation delay is the propagation delay of the service link between the terminal and the first cell corresponding to the first satellite, the second propagation delay is the propagation delay of the service link between the terminal and the second cell corresponding to the second satellite, the first satellite is the satellite that provides services to the terminal before the terminal switches, and the second satellite is the satellite that provides services to the terminal after the terminal switches. The access network device can reconfigure uplink resources for the terminal according to the second indication information.

[0018] In one possible design, the second indication information includes a difference.

[0019] In one possible design, the difference is the difference between the first propagation delay and the second propagation delay at at least one of the following moments: the moment when the first satellite stops providing services to the terminal, the moment when the second satellite starts providing services to the terminal, and the moment when the terminal accesses the second satellite.

[0020] In a fourth aspect, the present application provides a communication device, which may be a terminal or a module in a terminal (such as a circuit, a chip, a chip system or a processor), or a logical node, a logical module or software that can implement all or part of the terminal functions. The communication device has the function of implementing the first aspect or the second aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the first aspect or the second aspect above, and the module or unit or means may be implemented by software, or by hardware, or the corresponding software may be implemented by hardware.

[0021] In one possible design, the communication device includes a processing unit. Optionally, the communication device also includes an interface unit. The interface unit can be used to send and receive signals to achieve communication between the communication device and other devices; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the interface unit can correspond to the operations involved in the first aspect or the second aspect above.

[0022] In one possible design, the communication device includes a processor, which can be used to couple with a memory. The memory can store necessary computer programs or instructions for implementing the functions involved in the first aspect or the second aspect. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design of the first aspect or the second aspect.

[0023] In one possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for implementing the functions involved in the first aspect or the second aspect. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design of the first aspect or the second aspect.

[0024] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method in any possible design of the first aspect or the second aspect above.

[0025] In a fifth aspect, the present application provides a communication device, which may be an access network device or a module in an access network device (such as a circuit, a chip, a chip system or a processor), or a logical node, a logical module or software that can implement all or part of the functions of the access network device. The communication device has the function of implementing the third aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the third aspect above, and the module or unit or means may be implemented by software, or by hardware, or the corresponding software may be implemented by hardware.

[0026] In one possible design, the communication device includes a processing unit. Optionally, the communication device also includes an interface unit. The interface unit can be used to send and receive signals to achieve communication between the communication device and other devices; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the interface unit can correspond to the operations involved in the third aspect above.

[0027] In one possible design, the communication device includes a processor, which can be used to couple with a memory. The memory can store necessary computer programs or instructions for implementing the functions involved in the third aspect. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design of the third aspect.

[0028] In one possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for implementing the functions involved in the third aspect. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design of the third aspect.

[0029] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method in any possible design of the third aspect above.

[0030] It can be understood that in the fourth aspect or the fifth aspect above, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. In addition, the above processors can be one or more, and the memories can be one or more. The memory can be integrated with the processor, or the memory can be separately set from the processor. In the specific implementation process, the memory can be integrated with the processor on the same chip, or can be set on different chips respectively. The embodiment of the present application does not limit the type of memory and the setting method of the memory and the processor.

[0031] In a sixth aspect, the present application provides a communication system.

[0032] In a possible design, the communication system may include the communication device described in the fifth aspect and the communication device described in the sixth aspect. The communication device described in the fifth aspect is used to execute the communication method provided in the second aspect. For example, the communication system includes a terminal and an access network device; wherein the terminal is used to execute the communication method provided in the second aspect, and the access network device is used to execute the communication method provided in the third aspect.

[0033] In another possible design, the communication system may include the communication device and access network equipment described in the fifth aspect. The communication device described in the fifth aspect is used to execute the communication method provided in the first aspect. For example, the communication system includes a terminal and an access network device; wherein the terminal is used to execute the communication method provided in the first aspect, and the access network device is used to execute the operation performed by the first satellite or the second satellite in the communication method provided in the first aspect.

[0034] In a seventh aspect, the present application provides a computer-readable storage medium, in which a computer program or instruction is stored. When the computer program or instruction is executed, the method in any possible design of any aspect of the first to third aspects above is implemented.

[0035] In an eighth aspect, the present application provides a computer program product, which includes a computer program code. When the computer program code is executed, the method in any possible design of any aspect of the first to third aspects mentioned above is implemented.

[0036] In a ninth aspect, the present application provides a chip for reading a computer program stored in a memory to execute a method in any possible design of any one of the first to third aspects above.

[0037] The technical effects that can be achieved in any of the third to tenth aspects mentioned above can refer to the description of the technical effects that can be achieved in any possible design in any of the first to second aspects mentioned above, and the repetitions will not be discussed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figures 1A to 1E Architecture diagrams of several communication systems provided for this application;

[0039] FIG. 2A to FIG. 2B A schematic diagram of an application scenario provided for this application;

[0040] Figure 3 A flow chart of a communication method provided for this application;

[0041] Figure 4 A flow chart of another communication method provided by the present application;

[0042] Figure 5 A structural diagram of a communication device provided by this application;

[0043] Figure 6 A structural diagram of another communication device provided in this application. DETAILED DESCRIPTION

[0044] The technical solution in the embodiment of the present application will be described below in conjunction with the accompanying drawings in the embodiment of the present application. The technical solution in the embodiment of the present application can be applied to various communication systems, such as universal mobile telecommunications system (UMTS), wireless local area network (WLAN), wireless fidelity (Wi-Fi) system, fourth generation (4G) mobile communication system (such as long term evolution (LTE) system), fifth generation (5G) mobile communication system (such as NR system), NTN communication system, and future evolved communication system (such as sixth generation (6G) mobile communication system). The communication system can be applied to machine to machine (M2M) network, machine type communication (MTC) or other networks.

[0045] The present application will present various aspects, embodiments or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. In addition, combinations of these schemes may also be used.

[0046] The method provided in the embodiment of the present application can be applied to the NTN communication system. Figure 1A The architecture of an NTN communication system applicable to an embodiment of the present application is shown. The communication system may include a terminal, a first access network device, and a second access network device. The communication link between the first access network device and the second access network device is a feedback link (or feeder link); the communication link between the second access network device and the terminal is a service link.

[0047] The first access network device may be a gateway station (also called a ground station, earth station, gateway station, gateway or gateway station) (gateway) or a base station.

[0048] The second access network device may be a satellite (or satellite base station) or a high altitude platform station (HAPS). The satellite may include at least one of the following: a geostationary orbit (GEO) satellite (or geosynchronous orbit satellite) or a non-geostationary orbit (NGEO). The non-geostationary orbit satellite may include at least one of the following:

[0049] Medium earth orbit (MEO) satellite or low earth orbit (LEO) satellite. No limitation is made here.

[0050] In an embodiment of the present application, the communication mode of the second access network device may include a regenerative mode and a transparent mode (also referred to as a transparent mode). When the communication mode of the second access network device is the regenerative mode, the second access network device may serve as a base station for wireless communication. Exemplarily, the second access network device may include a next generation NodeB (gNB) or a distributed unit (DU), etc. When the communication mode of the second access network device is the transparent mode, the second access network device may perform frequency conversion forwarding on the signal.

[0051] It should be understood that Figure 1A Only one first access network device and one second access network device are shown. In actual use, the architecture of multiple first access network devices and / or one second access network device can be adopted as needed. Among them, each second access network device can provide services to one or more terminals, each second access network device can correspond to one or more first access network devices, and each first access network device can correspond to one or more second access network devices, which is not specifically limited in this application.

[0052] In the present application, a terminal may also be referred to as user equipment (UE), access terminal, subscriber unit, user station, mobile station, mobile station (MS), remote station, remote terminal, mobile device, user terminal, terminal equipment, wireless communication equipment, user agent or user device.

[0053] The terminal may be a device that provides a wireless communication function, such as a handheld device with a wireless connection function, a vehicle-mounted device, etc. At present, some examples of terminals are: mobile phones, satellite mobile terminals, cellular phones, smart phones, tablet computers, laptop computers, PDAs, mobile Internet devices (MID), wearable devices (such as smart watches, smart bracelets, pedometers, smart glasses, etc.), vehicle-mounted devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed railways, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point of sale (POS) machines, customer-premises equipment (CPE), wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes. The present invention relates to a wireless terminal (e.g., a refrigerator, a television, an air conditioner, an electric meter, etc.) in a home, an intelligent robot, a robotic arm, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with a wireless communication function, a computing device or other processing device connected to a wireless modem, a flying device (e.g., an intelligent robot, a hot air balloon, a drone, an airplane), a terminal in a 5th generation (5G) network, or a terminal in a public land mobile network (PLMN) to be evolved in the future, etc., and the embodiments of the present application are not limited to this. As an example and not a limitation, in the embodiments of the present application, the terminal may also be a mobile terminal (MT) in an integrated access and backhaul (IAB) node.When the IAB node faces its parent node, it can be regarded as a terminal. In this case, the IAB node plays the role of MT.

[0054] The embodiments of the present application do not limit the device form of the terminal. The device for implementing the function of the terminal can be a terminal; it can also be a device that can support the terminal to implement the function, such as a chip system. The device can be installed in the terminal or used in conjunction with the terminal. In the embodiments of the present application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0055] In the present application, access network equipment is a device that provides wireless communication functions for terminals, and terminals can communicate with core network equipment through access network equipment. As a node in the wireless access network, the access network equipment can also be called a base station, a radio access network (RAN) node (or device), and an access point (AP). The communication system may include multiple access network devices, and the multiple access network devices can be nodes of the same type or nodes of different types. In some scenarios, the roles of access network equipment and terminals are relative. For example, network element #A can be a helicopter or a drone, which can be configured as a mobile base station and access RAN through network element #B. For those terminals that access RAN through network element #A, network element #A is a base station; but for network element #B, network element #A is a terminal.

[0056] In one possible scenario, the access network device may be a base station, an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting point (TP), a gNB, a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, a satellite, or an access point (AP) in a WiFi system, an IAB node, a mobile switching center, or an access network device in an NTN communication system, that is, it may be deployed on a high-altitude platform or satellite, etc. The access network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a cloud RAN (CRAN) scenario. The access network device may also be a device that functions as a base station in device-to-device (D2D) communication, Internet of Vehicles communication, drone communication, or machine communication. Optionally, the access network device may also be a server, a wearable device, a vehicle or an onboard device, etc. For example, the access network device in the vehicle to everything (V2X) technology may be a road side unit (RSU).

[0057] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, and different access network devices respectively implement part of the functions of the base station. For example, the access network device may be a centralized unit (CU), DU, CU-control plane (CP), CU-user plane (UP), or radio unit (RU), etc. CU and DU may be set separately, or may be included in the same network element, such as a baseband unit (BBU). RU may be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It is understandable that the access network device may be a CU node, a DU node, or a device including a CU node and a DU node. In addition, CU may be divided into an access network device in an access network RAN, or CU may be divided into an access network device in a core network CN, without limitation here.

[0058] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, CU, CU-CP, CU-UP, DU and RU are described as examples in this application. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0059] In the embodiments of the present application, the form of the access network device is not limited. The device for realizing the function of the access network device may be the access network device; or it may be a device capable of supporting the access network device to realize the function, such as a chip system. The device may be installed in the access network device or used in combination with the access network device.

[0060] The access network equipment and terminals can be fixed or movable. The access network equipment and terminals can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on airplanes, balloons, and artificial satellites in the air. The embodiments of the present application do not limit the application scenarios of the access network equipment and terminals.

[0061] In the present application, the core network device is a network element included in the core network part of the mobile communication system. For example, the core network device is a network function (NF) network element and a user plane function (UPF) network element included in the core network part. The core network device can connect the terminal to different data networks, and perform services such as billing, mobility management, session management, and user plane forwarding. At present, some examples of NF network elements are: unified data management (UDM) network element, unified data repository (UDR) network element, network exposure function (NEF) network element, application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, network repository function (NRF) network element, etc.

[0062] The satellite communication system shown in the present application may have multiple possible architectures, for example, any one of architectures one to five.

[0063] Architecture 1: Figure 1B FIG. 1 shows a satellite communication system in a transparent transmission mode applicable to an embodiment of the present application. Figure 1B As shown in the figure, the terminal and the ground base station can communicate through the Uu interface, and the satellite and the NTN gateway can be considered as the RRU of the ground base station, which can realize transparent forwarding of signals. Among them, the satellite supports functions such as radio frequency filtering, frequency conversion and amplification; that is, the satellite can act as a layer 1 relay (L1 relay) to regenerate the physical layer signal.

[0064] Architecture 2: Figure 1C FIG. 2 shows a satellite communication system in a regeneration mode applicable to an embodiment of the present application. Figure 1CAs shown in FIG. 1 , a satellite has some or all functions of an access network device and can be called a satellite base station. A satellite can provide wireless access services and schedule wireless resources for terminal devices that access the network through the satellite. There is no inter-satellite link (ISL) between satellites.

[0065] Architecture 3: Figure 1D FIG. 2 shows another satellite communication system in a regeneration mode to which the embodiment of the present application is applicable. Figure 1D As shown, the satellite has some or all functions of the access network device and can be called a satellite base station. The satellite can provide wireless access services and schedule wireless resources for terminal devices that access the network through the satellite. There is an ISL between the satellites, for example, the ISL is a link on the Xn interface, and the satellites can communicate through the Xn interface.

[0066] Architecture 4: Figure 1E FIG. 2 shows another satellite communication system in a regeneration mode to which the embodiment of the present application is applicable. Figure 1E As shown in the figure, the satellite is equipped with DU and the ground base station includes CU. The NTN gateway can be considered as the RRU of the ground base station, which can realize transparent signal forwarding.

[0067] Architecture 5: The satellite is a base station with IAB function, and the terminal accesses the network through the satellite.

[0068] The following first explains the relevant terms involved in the embodiments of the present application. It should be noted that these explanations are intended to make the embodiments of the present application easier to understand and should not be regarded as limiting the scope of protection claimed by the present application.

[0069] (1) Random access process:

[0070] The random access process is initiated by the terminal to obtain uplink synchronization between the terminal and the access network device after the terminal and the access network device have achieved downlink synchronization. The random access process can be divided into a contention-based random access process and a non-contention-free random access process, which are described below.

[0071] The contention-based random access process may also be referred to as a 4-step random access process. In the contention-based random access process, the terminal may send a random access signal to the access network device, and the random access signal includes a preamble. The access network device may detect the preamble and estimate the propagation delay from the terminal to the access network device based on the preamble, thereby determining the timing advance (TA). The access network device sends a random access response (RAR) to the terminal, and the RAR includes the TA, the time-frequency resource location of the uplink scheduling configured by the access network device for the terminal, etc. The terminal sends a radio resource control (RRC) request at the time-frequency resource location included in the RAR, and the RRC request may also be referred to as message 3 (Msg3). After receiving the RRC request, the access network device may send a contention resolution message to the terminal, thereby completing the random access.

[0072] The non-contention-based random access process is also called a two-step random access process. In the non-contention-based random access process, the terminal can send a preamble according to the instruction of the preamble from the access network device. After receiving the preamble, the access network device sends a RAR to the terminal to complete the random access.

[0073] (2) Omitting the random access channel less (RACH-less) process:

[0074] When switching, the source access network device can send the TA of the target cell corresponding to the target access network device to the terminal. In this way, after the terminal is located in the coverage of the target cell, the TA can be used to perform uplink synchronization with the target access network device, that is, the terminal can perform uplink synchronization with the target access network device by omitting the random access process, so that it can communicate with the target access network device. Through this process, the terminal does not need to perform uplink synchronization with the target access network device through the random access process, thereby saving signaling and reducing the delay of terminal switching.

[0075] (3) Resources:

[0076] In the present application, resources may include time domain resources and / or frequency domain resources. Exemplarily, time domain resources may include resources on a subframe, a time slot, or a symbol; frequency domain resources may include resources on a resource block (RB) or a resource block group (RBG).

[0077] (4) Signal quality:

[0078] In the present application, signal quality may be signal strength. Among them, the parameters used to reflect or indicate signal strength may include but are not limited to at least one of the following: reference signal receiving power (RSRP), reference signal receiving quality (RSRQ), or received signal strength indication (RSSI).

[0079] (5) Synchronization signal and physical broadcast channel (PBCH) block (SSB):

[0080] At present, SSB may include synchronization signals and PBCH. Among them, the synchronization signal can be used by the terminal to perform downlink synchronization and obtain the identity (identity, ID) of the cell, and the downlink synchronization may include frequency synchronization and time synchronization. PBCH can be used by the terminal to obtain information about the accessed cell. Exemplarily, SSB may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS) and PBCH. Among them, PSS and SSS are both synchronization signals. PSS can be used to transmit the cell number, and SSS can be used to transmit the cell group number. The cell number and the cell group number together determine multiple physical cell numbers (physical cell identity, PCI) in the communication system. Once the terminal successfully searches for the PSS and SSS, it will know the PCI corresponding to the SSB. PBCH can be used to transmit the main information block (MIB). The MIB may include the system frame number and the subcarrier spacing for initial access, etc. The terminal can access the cell based on the MIB, etc.

[0081] (6) In the present application, the first SSB and the second SSB are the same, and have the same meaning as at least one of the following, and can be replaced with each other: the index of the first SSB and the index of the second SSB are the same, the beam corresponding to the first SSB and the beam corresponding to the second SSB are the same, the direction of the first SSB and the direction of the second SSB are the same, and the direction of the beam corresponding to the first SSB and the direction of the beam corresponding to the second SSB are the same. The first SSB and the second SSB are different, and have the same meaning as at least one of the following, and can be replaced with each other: the index of the first SSB and the index of the second SSB are different, the beam corresponding to the first SSB and the beam corresponding to the second SSB are different, the direction of the first SSB and the direction of the second SSB are different, and the direction of the beam corresponding to the first SSB and the direction of the beam corresponding to the second SSB are different. The terminal is in the coverage of the second satellite, which can be replaced by the terminal switching to the second satellite. Satellite transmission and satellite corresponding cell transmission can be replaced with each other, and satellite reception and satellite corresponding cell reception can be replaced with each other. Performing uplink synchronization can be replaced with performing synchronization; downlink synchronization can be replaced with synchronization.

[0082] In NTN, as the satellite moves, the satellite that can provide services to the terminal may change. For example, satellite 1 provides services to terminal 1 to terminal M, where M is a positive integer. As the satellite moves, terminal 1 to terminal M changes from being within the coverage of satellite 1 to being within the coverage of satellite 2, and thus needs to switch to satellite 2, which provides services to terminal 1 to terminal M. In this way, a large number of terminals may need to switch from one satellite to another in a short period of time. How to improve the efficiency of terminals when switching across satellites requires further research.

[0083] In some possible ways, when performing cross-satellite switching, the terminal can perform uplink synchronization with the target satellite by omitting the random access process, thereby communicating with the target satellite. Exemplarily, satellite 1 can broadcast time information 1, which can indicate one of the following: the moment when satellite 1 stops serving area 1 (for example, area 1 can be the coverage area of ​​the current satellite 1), the moment when satellite 2 starts serving area 1, or the moment when the terminal resynchronizes with satellite 2. Satellite 1 can also broadcast indication information 1, which indicates that the terminal can perform uplink synchronization with the target satellite by omitting the random access process. At the moment indicated by time information 1 or after the moment indicated by time information 1, the terminal can synchronize with the target satellite by omitting the random access process.

[0084] The above method may lead to at least one of the following problems:

[0085] Problem 1: If the optimal beam of the terminal before and after the switch is inconsistent, the terminal may not be able to receive messages from the target satellite and thus fail to successfully switch to the target satellite. Figure 2AAs shown, the terminal needs to switch from satellite 1 to satellite 2. Within the coverage of satellite 1, the optimal beam of the terminal is the beam corresponding to SSB1. Within the coverage of satellite 2, the optimal beam of the terminal is the beam corresponding to SSB2. If there are both beams corresponding to SSB1 and beams corresponding to SSB2 within the coverage of satellite 2, the access network device does not know that the optimal beam of the terminal is the beam corresponding to SSB2, and may continue to send messages to the terminal through the beam corresponding to SSB1, for example, sending a physical downlink control channel (PDCCH) used to configure uplink resources. Since the beam is directional, the terminal may not be able to receive messages from satellite 2 and thus cannot switch to satellite 2.

[0086] Question 2: When switching across satellites, if the service access network equipment of the terminal remains unchanged, the terminal can perform seamless transmission, but data conflicts may occur during transmission. For example, the terminal needs to switch from satellite 1 to satellite 2. The terminal communicates with satellite 1 through TA 1 and with satellite 2 through TA 2. Since the distance between the terminal and satellite 2 is greater than the distance between the terminal and satellite 1, TA 2 is greater than TA 1. In this way, the first scheduling in the target cell corresponding to satellite 2 may be performed at the same time as the last scheduling in the source cell corresponding to satellite 1, resulting in data conflicts. For example, Figure 2B As shown, subframe 3 sent by the terminal to the source cell and subframe 4 sent by the terminal to the target cell conflict in time, resulting in a conflict between data in subframe 3 sent by the terminal to the source cell and data in subframe 4 sent by the terminal to the target cell.

[0087] In view of this, an embodiment of the present application provides a communication method. Figure 3 The following is a flow chart corresponding to the communication method provided in the embodiment of the present application. Figure 3 In the method shown, a first cell corresponding to a first satellite is taken as a source cell of a terminal, and a second cell corresponding to a second satellite is taken as a target cell of the terminal. In other words, the first satellite is a satellite that provides services to the terminal before the terminal switches, and the second satellite is a satellite that provides services to the terminal after the terminal switches. Optionally, the cell identifiers (e.g., PCI) of the first cell and the second cell are the same or different. Figure 3 As shown, the method includes:

[0088] S301: A first cell sends first indication information to a terminal; correspondingly, the terminal receives the first indication information from the first cell.

[0089] There may be multiple times when the first cell sends the first indication information to the terminal. Exemplarily, when the terminal is about to leave the coverage of the first satellite, the first cell may send the first indication information to the terminal. For example, if the first satellite determines that the terminal leaves the coverage of the first satellite after a duration of 1, the first satellite may send the first indication information to the terminal. The basis for the first satellite to determine that the terminal leaves the coverage of the first satellite after a duration of 1 may include one or more of the ephemeris of the first satellite, the moving speed of the terminal, and the moving direction of the terminal. Duration 1 may be pre-configured, for example, specified by a protocol; it may also be determined by the first satellite; it may also be determined by other devices (for example, core network devices) and then notified to the first satellite.

[0090] The first indication information may be used to indicate that the terminal may perform uplink synchronization with the second satellite by not triggering a random access procedure; in other words, the first indication information may be used to indicate that the terminal may not trigger a random access procedure when performing uplink synchronization with the second satellite. Not triggering a random access procedure is, for example, performing an omitted random access procedure.

[0091] There may be multiple ways in which the first indication information indicates that the terminal can perform uplink synchronization with the second satellite without triggering a random access process, for example, way a1 or way a2.

[0092] Mode a1: The first indication information explicitly indicates that the terminal can perform uplink synchronization with the second satellite without triggering a random access procedure. For example, when the value of the first indication information is a first value (for example, 0 or 1), the terminal is indicated to perform uplink synchronization with the second satellite without triggering a random access procedure.

[0093] Mode a2: The first indication information implicitly indicates that the terminal can perform uplink synchronization with the second satellite without triggering a random access process. For example, the first indication information includes the parameter N TA , N TA The value can be 0 or the N used by the terminal in the first cell. TA , the N used by the terminal in the first cell TA It can be used to determine the TA used by the terminal in the first cell. TA After that, the terminal may determine to perform uplink synchronization with the second satellite by not triggering the random access process. Optionally, after receiving N TA After that, the terminal can TA To calculate or adjust the initial TA used by the terminal in the second cell. TA , the location of the terminal, the ephemeris of the first satellite and the ephemeris of the second satellite, and determine an initial TA used by the terminal in the second cell. The ephemeris of the first satellite and the ephemeris of the second satellite may be obtained by the terminal from the first satellite.

[0094] The first indication information can be carried in a traditional message or in a new message; the first indication information can be carried in a message broadcast by the first cell or in a unicast message sent by the first cell to the terminal, and this application does not impose any restrictions on this.

[0095] S302: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, the terminal may perform uplink synchronization with the second satellite without triggering a random access process; that is, the terminal may not trigger a random access process and perform uplink synchronization with the second satellite; or, the terminal performs uplink synchronization with the second satellite but does not trigger a random access process.

[0096] Among them, the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite; in other words, the terminal can use the first SSB to communicate with the first satellite, and the terminal can use the second SSB to communicate with the second satellite.

[0097] In some possible ways, after the terminal is in the coverage of the second satellite, the terminal may determine the second SSB. If the first SSB and the second SSB are the same, the terminal may perform uplink synchronization with the second satellite without triggering a random access procedure.

[0098] Optionally, the timing at which the terminal determines the second SSB may be determined based on indication information 2 from the first cell; in other words, the first cell sends indication information 2 to the terminal, and indication information 2 may be used to determine the timing at which the terminal determines the second SSB. The indication information 2 may be carried in a traditional message or in a new message. The indication information 2 may be carried in the same message as the first indication information or in different messages. The indication information 2 may be a message broadcast by the first cell or a unicast message sent by the first cell to the terminal.

[0099] In some possible ways, the indication information 2 indicates that the terminal needs to resynchronize. In this way, after receiving the indication information 2, the terminal can determine the second SSB.

[0100] In some other possible ways, the indication information 2 includes time information 2, and the time information 2 may indicate moment 1, and moment 1 is related to the timing when the terminal determines the second SSB. Among them, moment 1 may be one of the following: the moment when the first satellite stops serving area 2 (for example, area 2 may be the coverage area of ​​the current first satellite) (may be called t-Service), the moment when the second satellite starts serving area 2 (may be called t-Start), or the moment when the terminal resynchronizes uplink with the second satellite. Among them, the moment when the second satellite starts serving area 2 can be represented by the time interval (may be called t-gap) between the moment when the second satellite starts serving area 2 and the moment when the first satellite stops serving area 2, and the time interval may be an integer, a negative number, or 0.

[0101] For example, time 1 is the time when the first satellite stops serving area 2. The terminal may determine the second SSB at time 1 or at time 2 before time 1 or at time 3 after time 1. Duration 2 and duration 3 may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0102] For another example, time 1 is the time when the second satellite starts serving area 2. The terminal may determine the second SSB at time 1 or at a duration 4 before time 1 or at a duration 5 after time 1. Duration 4 and duration 5 may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0103] For another example, time 1 is the time when the terminal resynchronizes with the second satellite, and the terminal may determine the second SSB at time 1 or time duration 6 after time 1. The time duration 6 may be preconfigured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0104] There are multiple ways for the terminal to determine the second SSB, for example, method b1, method b2 or method b3.

[0105] Mode b1: After the terminal is in the coverage of the second satellite, the terminal determines whether it can receive the first SSB from the second cell. If the terminal can receive the first SSB from the second cell, the terminal can determine the first SSB as the second SSB; that is, the first SSB and the second SSB are the same, and the terminal can use the first SSB to communicate with the second satellite. If the first SSB from the second cell cannot be received, the terminal can determine the SSB with the best signal quality from the second cell or any SSB from the second cell whose signal quality is greater than threshold 1 as the second SSB.

[0106] Mode b2: After the terminal is in the coverage of the second satellite, the terminal determines whether it can receive the first SSB from the second cell. If the terminal can receive the first SSB from the second cell, and the signal quality of the first SSB is greater than the first signal quality threshold, the terminal can determine the first SSB as the second SSB; that is, the first SSB and the second SSB are the same, and the terminal can use the first SSB to communicate with the second satellite. If the terminal can receive the first SSB from the second cell, and the signal quality of the first SSB is less than or equal to the first signal quality threshold; or, if the terminal cannot receive the first SSB from the second cell, the terminal can determine the SSB with the best signal quality from the second cell or any SSB from the second cell with a signal quality greater than threshold 1 as the second SSB. The first signal quality threshold may be pre-configured, for example, specified by the protocol; may also be determined by the terminal; and may also be configured for the terminal by other devices (for example, the first satellite or the second satellite).

[0107] Optionally, in mode b2, greater than can be replaced by greater than or equal to, and less than or equal to can be replaced by less than.

[0108] Mode b3: After the terminal is in the coverage of the second satellite, the terminal can determine the SSB with the best signal quality from the second cell or any SSB with a signal quality greater than threshold 1 from the second cell as the second SSB. In other words, the second SSB is the SSB with the best signal quality from the second cell or the SSB with a signal quality greater than threshold 1.

[0109] In modes b1 to b3, threshold 1 may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be configured for the terminal by other devices (for example, the first satellite or the second satellite).

[0110] As mentioned above, in S302, the terminal may perform uplink synchronization with the second satellite by not triggering the random access process. Exemplarily, the terminal performs uplink synchronization with the second satellite by omitting the random access process; in other words, the terminal may perform the omission of the random access process, thereby achieving uplink synchronization between the terminal and the second satellite. The specific content of omitting the random access process can refer to the explanation of omitting the random access process in the above terminology explanation part, except that the source access network device is replaced by the first satellite or the first cell, and the target access network device is replaced by the second satellite or the second cell, which will not be repeated here.

[0111] In some possible ways, in S302, the terminal performs uplink synchronization with the second satellite by not triggering a random access process, which may include: the terminal sets the corresponding parameter N of the second cell TA The value of or the parameter N corresponding to the TA group where the second cell is locatedTA The value of is set to the parameter N received by the terminal in the first cell TA The value of parameter N received by the terminal in the first cell TA It can be the parameter N included in the first indication information TA , or it may be a parameter N sent by the first cell to the terminal through information other than the first indication information TA .

[0112] pass Figure 3 According to the method shown, after the terminal is in the coverage of the second satellite, the terminal can perform uplink synchronization with the second satellite by not triggering a random access process, thereby improving the efficiency of the terminal when switching across satellites. Moreover, in the method, only when the first SSB and the second SSB are the same, the terminal can perform uplink synchronization with the second satellite by not triggering a random access process, so that the terminal can receive a message from the second satellite through the beam corresponding to the second SSB and successfully switch to the second satellite, thereby solving the above problem 1.

[0113] Some possible ways are Figure 3 The method also includes step A1:

[0114] Step A1: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, the terminal performs uplink synchronization with the second satellite through a random access process; in other words, the terminal triggers or executes a random access process to perform uplink synchronization with the second satellite. The specific content of the random access process can be referred to the description of the random access process in the term explanation part, except that the access network device is replaced by the second satellite or the second cell, which will not be repeated here.

[0115] In some possible ways, after the terminal is in the coverage of the second satellite, the terminal may determine the second SSB. If the first SSB and the second SSB are different, the terminal performs uplink synchronization with the second satellite through a random access process. The timing and manner of the terminal determining the second SSB can refer to the description of the timing and manner of the terminal determining the second SSB in S302, which will not be repeated here.

[0116] In this manner, when the first SSB and the second SSB are different, the terminal can perform uplink synchronization with the second satellite by triggering a random access process, thereby avoiding the situation where the terminal is unable to receive messages from the second satellite when the terminal performs uplink synchronization with the second satellite without triggering the random access process, thereby enabling the terminal to receive messages from the second satellite and successfully switch to the second satellite.

[0117] Among other possible approaches, Figure 3 The method shown also includes steps B1 to B2:

[0118] Step B1: the first cell or the second cell sends resource configuration information to the terminal; correspondingly, the terminal receives the resource configuration information from the first cell or the second cell.

[0119] The resource configuration information is used to configure uplink resources. The uplink resources can be used for the terminal to send messages to the second satellite after being in the coverage of the second satellite. Exemplarily, the resource configuration information may include indication information of the uplink resources. For example, the resource information may include: frequency domain offset information and time domain information. The frequency domain offset information indicates the frequency offset between the uplink resource and the center frequency point, and the time domain information indicates the time domain position of the uplink resource (e.g., the starting frame, and / or the starting symbol). The resource configuration information may be carried in a traditional message or in a new message. The resource configuration information may be carried in the same message as the first indication information, or in different messages.

[0120] In some possible manners, when step B1 includes the first cell sending resource configuration information to the terminal, when the terminal is about to leave the coverage of the first satellite, the first cell may send the resource configuration information to the terminal. For specific content of the terminal being about to leave the coverage of the first satellite, reference may be made to the description of the terminal being about to leave the coverage of the first satellite in S301, which will not be repeated here.

[0121] Optionally, in order to enable the second cell to receive a message from the terminal through the uplink resource, the second cell may learn that the uplink resource is used for the terminal to send a message to the second cell after being in the coverage of the second satellite. In some examples, after the first cell configures the uplink resource for the terminal, it may notify the second cell that the uplink resource is used for the terminal to send a message to the second cell after being in the coverage of the second satellite. In other examples, the uplink resource is a resource configured by the second cell for the terminal for sending a message. After configuring the uplink resource, the second cell notifies the first cell of the uplink resource, and then the first cell may execute step B1.

[0122] In some other possible ways, when step B1 includes the second cell sending resource configuration information to the terminal, after the terminal is in the coverage of the second satellite, the second cell may send the resource configuration information to the terminal. Exemplarily, the second cell may broadcast the resource configuration information, so that after the terminal is in the coverage of the second satellite, the terminal can receive the resource configuration information from the second cell.

[0123] Step B2: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, the terminal sends a message to the second cell through the uplink resource configured by the resource configuration information. Exemplarily, after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, the terminal sends a message containing data and / or control information to the second cell through the uplink resource.

[0124] Optionally, the terminal may send information indicating the second SSB to the second cell through the uplink resources (e.g., initial uplink resources) configured by the resource configuration information. In this way, the terminal may notify the second cell of the second SSB so that the second cell uses the second SSB to communicate with the terminal. In some examples, the information indicating the second SSB may explicitly indicate the second SSB, for example, the information indicating the second SSB is the index of the second SSB. In other examples, the information indicating the second SSB may implicitly indicate the second SSB, for example, the information indicating the second SSB may be information that corresponds to the second SSB. The information indicating the second SSB may be carried in a traditional message or in a new message, and the present application does not impose any restrictions on this.

[0125] In this manner, when the first SSB and the second SSB are different, the terminal can send a message to the second cell through the uplink resources configured by the resource configuration information, thereby reducing the delay in sending the message to the second cell.

[0126] In some possible approaches, S302 may be replaced by step C1.

[0127] Step C1: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is greater than the first threshold, the terminal can perform uplink synchronization with the second satellite without triggering a random access process. Among them, the specific content of the terminal performing uplink synchronization with the second satellite by not triggering a random access process can refer to the description of the terminal performing uplink synchronization with the second satellite by not triggering a random access process in S302; the timing and method of the terminal determining the second SSB can refer to the description of the timing and method of the terminal determining the second SSB in S302, which will not be repeated here. The first threshold can be pre-configured, for example, specified by a protocol; it can also be determined by the terminal; it can also be configured for the terminal by other devices (for example, the first satellite or the second satellite).

[0128] Optionally, the greater than in step C1 may be replaced by greater than or equal to.

[0129] In this manner, after the terminal is in the coverage of the second satellite, the terminal can perform uplink synchronization with the second satellite by not triggering a random access process, thereby improving the efficiency of the terminal when switching across satellites. Moreover, in this manner, when the first SSB and the second SSB are the same and the signal quality of the second SSB is greater than a first threshold, the terminal performs uplink synchronization with the second satellite by not triggering a random access process, thereby enabling the terminal to receive a message from the second satellite and successfully switch to the second satellite.

[0130] In some implementations, Figure 3 The method shown also includes step D1:

[0131] Step D1: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same and the signal quality of the second SSB is less than or equal to the first threshold, the terminal can perform uplink synchronization with the second satellite through a random access process.

[0132] Among them, the specific content of the terminal performing uplink synchronization with the second satellite through the random access process can refer to the description of the terminal performing uplink synchronization with the second satellite through the random access process in step A1; the specific content of the first threshold can refer to the description of the first threshold in step C1, which will not be repeated here.

[0133] Optionally, less than or equal to in step D1 may be replaced by less than.

[0134] In this implementation, when the first SSB and the second SSB are the same and the signal quality of the second SSB is less than or equal to the first threshold, the terminal can perform uplink synchronization with the second satellite by triggering a random access process, thereby avoiding or reducing the terminal's inability to receive messages from the second satellite when the terminal performs uplink synchronization with the second satellite without triggering the random access process, thereby enabling the terminal to receive messages from the second satellite and allowing the terminal to successfully switch to the second satellite.

[0135] In other implementations, Figure 3 The method shown also includes steps E1 to E2:

[0136] Step E1: the first cell or the second cell sends resource configuration information to the terminal; correspondingly, the terminal receives the resource configuration information from the first cell or the second cell.

[0137] The specific content of step E1 can refer to step B1 and will not be repeated here.

[0138] Step E2: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, the terminal may send a message to the second cell through the uplink resources configured by the resource configuration information. Exemplarily, after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, the terminal sends a message containing data and / or control information to the second cell through the uplink resources.

[0139] Optionally, the terminal may send information indicating the second SSB to the second cell through the uplink resources (e.g., initial uplink resources) configured by the resource configuration information. In this way, the terminal may notify the second cell of the second SSB so that the second cell uses the second SSB to communicate with the terminal. For the specific content of the information indicating the second SSB, please refer to the description of the information indicating the second SSB in step B2, which will not be repeated here.

[0140] In this manner, when the first SSB is the same as the second SSB and the signal quality of the second SSB is less than or equal to the first threshold, the terminal can send a message to the second cell through the uplink resources configured by the resource configuration information, thereby reducing the delay in sending the message to the second cell.

[0141] Some possible ways are Figure 3 The method shown also includes steps S303 to S304:

[0142] S303: The first cell sends indication information 2 to the terminal; correspondingly, the terminal receives indication information 2 from the first cell.

[0143] The indication information 2 may be used to determine the timing for the terminal to perform downlink synchronization with the second cell. The specific content of the indication information 2 may refer to the description of the indication information 2 in S302, and the repeated parts will not be repeated.

[0144] S304: The terminal and the second cell perform downlink synchronization.

[0145] In some possible ways, the indication information 2 indicates that the terminal needs to be resynchronized. In this way, after receiving the indication information 2, the terminal can start to switch to the second satellite and perform downlink synchronization with the second satellite.

[0146] In some other possible ways, the indication information 2 includes time information 2, and the time information 2 may indicate a moment 1, and the moment 1 is related to the timing of downlink synchronization between the terminal and the second cell. The terminal may perform downlink synchronization with the second cell according to the moment 1. For the specific content of the moment 1, reference may be made to the description of the moment 1 in S302, which will not be repeated here.

[0147] For example, time 1 is the time when the first satellite stops serving area 2. The terminal may start switching to the second satellite at time 1 or at time 7 before time 1 or at time 8 after time 1, and perform downlink synchronization with the second satellite. The time 7 and the time 8 may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0148] For another example, time 1 is the time when the second satellite starts serving area 2. The terminal may start switching to the second satellite at time 1 or at time 9 before time 1 or at time 10 after time 1, and perform downlink synchronization with the second satellite. Wherein, time 9 and time 10 may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0149] For another example, time 1 is the time when the terminal resynchronizes with the second satellite, and the terminal may start switching to the second satellite and perform downlink synchronization with the second satellite at time 1 or at a time length 11 after time 1. The time length 11 may be preconfigured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal.

[0150] This application does not limit the specific process of downlink synchronization, nor does it limit the execution order of S304 and the terminal determining the second SSB.

[0151] Some possible ways are Figure 3 The method shown also includes step G1:

[0152] Step G1: The second cell sends a PDCCH through the beam corresponding to the second SSB; accordingly, the terminal monitors the PDCCH from the second cell through the beam corresponding to the second SSB. The PDCCH can be used to schedule uplink transmission resources for the terminal. In this way, the terminal can send a message to the second cell according to the uplink transmission resources.

[0153] Optionally, step G1 may occur after the terminal and the second cell perform uplink synchronization. For example, step G1 may occur after S302, step A1, step C1 or step D1.

[0154] An embodiment of the present application provides another communication method. Figure 4 The following is a flow chart corresponding to the communication method provided in the embodiment of the present application. Figure 4In the method shown, a first cell corresponding to a first satellite is taken as a source cell of a terminal, and a second cell corresponding to a second satellite is taken as a target cell of the terminal. In other words, the first satellite is a satellite that provides services to the terminal before the terminal switches, and the second satellite is a satellite that provides services to the terminal after the terminal switches. Optionally, the cell identifiers (e.g., PCI) of the first cell and the second cell are the same or different. Figure 4 As shown, the method includes:

[0155] S401: The terminal determines a difference between a first propagation delay and a second propagation delay.

[0156] There are many possible ways for the first propagation delay and the second propagation delay, for example, way c1 or way c2.

[0157] Mode c1: The first propagation delay is the propagation delay of the service link between the terminal and the first cell, and the second propagation delay is the propagation delay of the service link between the terminal and the second cell. For example, if the propagation delay of the service link between the terminal and the first cell is T1, and the propagation delay of the service link between the terminal and the second cell is T2, then the first propagation delay is T1, the second propagation delay is T2, and the difference between the first propagation delay and the second propagation delay may be T2-T1.

[0158] Mode c2: The first propagation delay is the sum of the propagation delay of the service link between the terminal and the first cell and the propagation delay of the link between the first satellite and the first reference point; the second propagation delay is the sum of the propagation delay of the service link between the terminal and the second cell corresponding to the second satellite and the propagation delay of the link between the second satellite and the second reference point. The first reference point is a point between the first satellite and the ground station (or base station). The second reference point is a point between the second satellite and the ground station (or base station).

[0159] Exemplarily, the first reference point and the second reference point are ground stations or base stations. The first propagation delay may be the sum of the propagation delay of the service link between the terminal and the first cell and the propagation delay of the feedback link between the first satellite and the ground station. The second propagation delay may be the sum of the propagation delay of the service link between the terminal and the second cell and the propagation delay of the feedback link between the second satellite and the ground station. For example, if the propagation delay of the service link between the terminal and the first cell is T1, the propagation delay of the feedback link between the first satellite and the ground station is T3, the propagation delay of the service link between the terminal and the second cell is T2, and the propagation delay of the feedback link between the second satellite and the ground station is T4, then the first propagation delay is T1+T3, the second propagation delay is T2+T4, and the difference between the first propagation delay and the second propagation delay may be T2+T4-T1-T3.

[0160] There may be various times at which the difference between the first propagation delay and the second propagation delay corresponds.

[0161] In some possible ways, the terminal may determine the difference between the first propagation delay and the second propagation delay at the current moment; in other words, the terminal may determine the difference between the first propagation delay and the second propagation delay in real time. In some examples, the terminal may periodically determine the difference between the first propagation delay and the second propagation delay. Among them, the determination period may be pre-configured, for example, specified by the protocol; it may also be determined by the terminal; it may also be determined by other devices (for example, the first satellite or the second satellite) and then notified to the terminal. In other examples, the terminal may determine the difference between the first propagation delay and the second propagation delay based on an event trigger. For example, after receiving an indication 1 from the first cell or the second cell, the terminal determines the difference between the first propagation delay and the second propagation delay at the current moment, and the indication 1 is used to instruct the terminal to determine the difference between the first propagation delay and the second propagation delay.

[0162] In some other possible ways, the terminal can predict the difference between the first propagation delay and the second propagation delay at at least one of the following moments: the moment when the first satellite stops providing services for the terminal, the moment when the second satellite starts providing services for the terminal, and the moment when the terminal accesses the second satellite. In other words, the difference is the difference between the first propagation delay and the second propagation delay at at least one of the following moments: the moment when the first satellite stops providing services for the terminal, the moment when the second satellite starts providing services for the terminal, and the moment when the terminal accesses the second satellite. In this way, the amount of calculation of the terminal can be reduced and the energy consumption of the terminal can be reduced.

[0163] Optionally, the terminal may determine the first propagation delay and the second propagation delay according to the NTN parameter and the location of the terminal. There are multiple ways to determine the first propagation delay and the second propagation delay, for example, way d1 or way d2.

[0164] Mode d1: The first propagation delay and the second propagation delay are implemented in mode c1. The NTN parameters may include the ephemeris of the first satellite and the ephemeris of the second satellite. The terminal may determine the first propagation delay according to the ephemeris of the first satellite and the position of the terminal; and determine the second propagation delay according to the ephemeris of the second satellite and the position of the terminal. The position of the terminal may be the real-time position of the terminal, or may be the predicted position of the terminal at at least one of the following moments: the moment when the first satellite stops providing services to the terminal, the moment when the second satellite starts providing services to the terminal, and the moment when the terminal accesses the second satellite.

[0165] Exemplarily, if the terminal determines that the distance between the first satellite and the terminal is d1 based on the ephemeris of the first satellite and the position of the terminal, the first propagation delay T1 is d1 / c, where c is the speed of light. If the terminal determines that the distance between the second satellite and the terminal is d2 based on the ephemeris of the second satellite and the position of the terminal, the second propagation delay T2 is d2 / c, where c is the speed of light.

[0166] The following describes the manner in which the terminal obtains the NTN parameter. The NTN parameter may be obtained by the terminal from the first cell and / or the second cell. For example, the terminal obtains the NTN parameter including the ephemeris of the first satellite and the ephemeris of the second satellite from the first cell or the second cell. For another example, the terminal obtains the NTN parameter including the ephemeris of the first satellite from the first cell, and obtains the NTN parameter including the ephemeris of the second satellite from the second cell.

[0167] Optionally, the NTN parameter may be carried in a broadcast message sent by the first cell and / or the second cell, or may be carried in a unicast message sent by the first cell and / or the second cell to the terminal.

[0168] Mode d2: The first propagation delay and the second propagation delay are implemented in mode c2. The terminal may determine the first propagation delay and the second propagation delay according to the NTN parameters, the location of the terminal, the location of the first reference point, and the location of the second reference point. The NTN parameters may include the ephemeris of the first satellite and the ephemeris of the second satellite.

[0169] Optionally, the terminal may determine the first propagation delay according to the ephemeris of the first satellite, the position of the terminal and the position of the first reference point; and determine the second propagation delay according to the ephemeris of the second satellite, the position of the terminal and the position of the second reference point. The specific content of the terminal's position can refer to the description of the terminal's position in method d1, which will not be repeated here. For example, if the terminal determines that the distance between the first satellite and the terminal is d1 according to the ephemeris of the first satellite and the position of the terminal, and determines that the distance between the first satellite and the first reference point is d3 according to the ephemeris of the first satellite and the position of the first reference point, then the first propagation delay is (d1+d3) / c, where c is the speed of light. If the terminal determines that the distance between the second satellite and the terminal is d2 according to the ephemeris of the second satellite and the position of the terminal, and determines that the distance between the second satellite and the second reference point is d4 according to the ephemeris of the second satellite and the position of the second reference point, then the second propagation delay is (d2+d4) / c, where c is the speed of light.

[0170] For the specific content of the terminal obtaining the NTN parameter, please refer to the description of the method for the terminal to obtain the NTN parameter in method d1, which will not be repeated here. For the method for the terminal to obtain the position of the first reference point and the position of the second reference point, please refer to the description of the method for the terminal to obtain the NTN parameter in method d1, except that the NTN parameter is replaced by the position of the first reference point and the position of the second reference point, which will not be repeated here.

[0171] S402: When the difference between the first propagation delay and the second propagation delay is greater than a second threshold, the terminal sends second indication information; correspondingly, the access network device receives the second indication information.

[0172] The access network device may be the first satellite or a base station located on the ground. The second threshold may be pre-configured, for example, specified by a protocol; may be determined by the terminal; or may be determined by other devices (for example, the access network device) and then notified to the terminal.

[0173] The second indication information may be used to indicate reconfiguration of uplink resources for the terminal. The second indication information may indicate multiple ways of reconfiguring uplink resources for the terminal, for example, way e1 or way e2.

[0174] Mode e1: The second indication information explicitly indicates to reconfigure uplink resources for the terminal. For example, the second indication information is a request for reconfiguring uplink resources for the terminal. Thus, after receiving the second indication information, the access network device may determine to reconfigure uplink resources for the terminal.

[0175] Mode e2: The second indication information may implicitly indicate that the uplink resources are to be reconfigured for the terminal. For example, the second indication information includes the difference between the first propagation delay and the second propagation delay. Thus, after receiving the second indication information, the access network device may determine that the uplink resources are to be reconfigured for the terminal. Furthermore, since the second indication information includes the difference between the first propagation delay and the second propagation delay, the access network device may also reconfigure the uplink resources for the terminal according to the difference, thereby effectively avoiding data conflicts.

[0176] Optionally, in S402, greater than can be replaced by greater than or equal to.

[0177] In some possible embodiments, S402 may be replaced by: when the absolute value of the difference between the first propagation delay and the second propagation delay is greater than a second threshold, the terminal sends second indication information; correspondingly, the access network device receives the second indication information.

[0178] S403: The access network device reconfigures uplink resources for the terminal according to the second indication information.

[0179] In some possible ways, the second indication information explicitly indicates to reconfigure uplink resources for the terminal, and the access network device can reconfigure uplink resources for the terminal, thereby avoiding or reducing data conflicts generated when the terminal performs cross-satellite switching.

[0180] In some other possible ways, the second indication information includes the difference between the first propagation delay and the second propagation delay. The access network device can reconfigure uplink resources for the terminal according to the difference. Optionally, the access network device can release the conflicting uplink resources. For example, Figure 2B As shown, subframe 3 sent by the terminal to the source cell and subframe 4 sent by the terminal to the target cell conflict in time, and the access network device can release the resources of subframe 4. In this way, data conflicts generated when the terminal performs cross-satellite switching can be avoided.

[0181] Optional, Figure 4 The method shown further comprises a step H1.

[0182] Step H1: The first cell sends first indication information to the terminal; accordingly, the terminal receives the first indication information from the first cell. The first indication information can be used to indicate that the terminal can perform uplink synchronization with the second satellite without triggering a random access process.

[0183] The specific content of step H1 can be referred to S301 and will not be repeated here.

[0184] pass Figure 4 In the method shown, when the difference between the first propagation delay and the second propagation delay is greater than the second threshold, the terminal may send a second indication information, and the second indication information may be used to indicate reconfiguration of uplink resources for the terminal. The first propagation delay is related to the first satellite that provides services to the terminal before the terminal switches, and the second propagation delay is related to the second satellite that provides services to the terminal after the terminal switches. In this way, in the cross-satellite switching scenario, the access network device can reconfigure uplink resources for the terminal, thereby avoiding or reducing data conflicts generated when the terminal performs cross-satellite switching, solving the above problem 2.

[0185] Based on the same technical concept as the above method embodiment, the embodiment of the present application provides a corresponding communication device, which can be used to perform the functions of the relevant steps in the above method embodiment. The function can be implemented by hardware, can be implemented by software, or can be implemented by hardware executing the corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a terminal, or can be a module in a terminal (such as a circuit or a chip), or can be a logical node, a logical module or software that can implement all or part of the terminal functions; or the communication device can be an access network device or a module in an access network device (such as a circuit or a chip), or can be a logical node, a logical module or software that can implement all or part of the access network device functions.

[0186] In a possible implementation, the structure of the communication device provided in the embodiment of the present application is as follows: Figure 5 As shown, the communication device 500 includes a processing unit 502. Optionally, the communication device further includes an interface unit 501. The functions of each unit in the communication device 500 are introduced below.

[0187] The interface unit 501 is used to input and / or output information. The input information can be replaced by receiving information, and the output information can be replaced by sending information. When outputting information, the interface unit 501 can output information to other devices outside the communication device 500, or it can output information to other units in the communication device 500. In some embodiments, the interface unit 501 can be implemented by at least one of a physical interface, a communication module, a communication interface, and an input and output interface. In other embodiments, the interface unit 501 can be implemented by an interface circuit, for example, a mobile communication module. Among them, the mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc.

[0188] The processing unit 502 can be used to support the communication device 500 to perform the processing actions in the above method embodiment. The processing unit 502 can be implemented by one or more processors. For example, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0189] In one embodiment, the communication device 500 is applied to Figure 3 The terminal in the embodiment of the present application is shown. The specific functions of the processing unit 502 in this implementation manner are introduced below.

[0190] The processing unit 502 is used to: receive first indication information from the first cell corresponding to the first satellite through the interface unit 501, the first indication information is used to instruct the terminal to perform uplink synchronization with the second satellite by not triggering a random access process; after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, perform uplink synchronization with the second satellite by not triggering a random access process, the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite.

[0191] In some possible embodiments, the processing unit 502 is further used to: after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, perform uplink synchronization with the second satellite by not triggering a random access process.

[0192] In some other possible embodiments, the processing unit 502 is also used to: after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same and the signal quality of the second SSB is less than or equal to the first threshold, then uplink synchronization with the second satellite is performed through a random access process.

[0193] Optionally, the processing unit 502 is also used to: receive resource configuration information of the second cell corresponding to the first cell or the second satellite through the interface unit 501, and the resource configuration information is used to configure uplink resources; after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, and the signal quality of the second SSB is less than or equal to the first threshold, then send a message to the second cell through the uplink resources through the interface unit 501.

[0194] In some implementations, the processing unit 502 is further used to: after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, perform uplink synchronization with the second satellite through a random access process.

[0195] In some other implementations, the processing unit 502 is also used to: receive resource configuration information from the first cell or the second cell corresponding to the second satellite through the interface unit 501, and the resource configuration information is used to configure uplink resources; after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, send a message to the second cell through the uplink resources through the interface unit 501.

[0196] Optionally, the processing unit 502 is further used to: send information indicating the second SSB to the second cell through uplink resources via the interface unit 501.

[0197] In another embodiment, the communication device 500 is applied to Figure 4 The terminal in the embodiment of the present application is shown. The specific functions of the processing unit 502 in this implementation manner are introduced below.

[0198] The processing unit 502 is used to: determine a difference between a first propagation delay and a second propagation delay, where the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to the first satellite, and the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to the second satellite, where the first satellite is a satellite that provides services to the terminal before the terminal is switched, and the second satellite is a satellite that provides services to the terminal after the terminal is switched; and when the difference is greater than a second threshold, send second indication information through the interface unit 501, where the second indication information is used to indicate reconfiguration of uplink resources for the terminal.

[0199] In some possible embodiments, the processing unit 502 is specifically used to: predict the difference between the first propagation delay and the second propagation delay at at least one of the following moments: the moment when the first satellite stops providing services to the terminal, the moment when the second satellite starts providing services to the terminal, and the moment when the terminal accesses the second satellite.

[0200] In yet another embodiment, the communication device 500 is applied to Figure 4 The access network device in the embodiment of the present application is shown. The specific functions of the processing unit 502 in this implementation manner are introduced below.

[0201] The processing unit 502 is configured to: receive, through the interface unit 501, second indication information sent by the terminal when the difference between the first propagation delay and the second propagation delay is greater than a second threshold, where the second indication information is used to indicate reconfiguration of uplink resources for the terminal, the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to the first satellite, the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to the second satellite, the first satellite is a satellite that provides services to the terminal before the terminal is switched, and the second satellite is a satellite that provides services to the terminal after the terminal is switched; and reconfigure uplink resources for the terminal according to the second indication information.

[0202] For a more detailed description of the processing unit 502 and the interface unit 501, please refer to Figure 3 and Figure 4 The relevant description in the method embodiment shown is directly obtained and will not be repeated here.

[0203] It should be noted that the division of modules in the above embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, or may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0204] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

[0205] In a possible implementation, the communication device provided in the embodiment of the present application refers to Figure 6 As shown, the communication device 600 includes: a processor 602. Optionally, the communication device 600 also includes: an interface circuit 601 and a memory 603. The interface circuit 601, the processor 602 and the memory 603 are coupled to each other.

[0206] Optionally, the interface circuit 601, the processor 602 and the memory 603 are coupled to each other via a bus 604. The bus 604 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0207] The interface circuit 601 is used to input and / or output information. The input information can be replaced by receiving information, and the output information can be replaced by sending information. When outputting information, the interface circuit 601 can output information to other devices outside the communication device 600, or can output information to other units in the communication device 600. Exemplarily, the interface circuit 601 can be implemented by at least one of a physical interface, a communication module, a communication interface, an input-output interface, and a mobile communication module. Among them, the mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, an LNA, etc.

[0208] The processor 602 may be used to support the communication device 600 in executing the processing actions in the above method embodiment. When the communication device 600 is used to implement the above method embodiment, the processor 602 may also be used to implement the functions of the above processing unit 502. The processor 602 may be a CPU, or other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor, or any conventional processor.

[0209] In one embodiment, the communication device 600 is applied to Figure 3 The terminal in the embodiment of the present application is shown. The specific functions of the processor 602 in this implementation are introduced below.

[0210] The processor 602 is used to: receive first indication information from the first cell corresponding to the first satellite through the interface circuit 601, the first indication information is used to instruct the terminal to perform uplink synchronization with the second satellite by not triggering a random access process; after the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are the same, perform uplink synchronization with the second satellite by not triggering a random access process, the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite.

[0211] In another embodiment, the communication device 600 is applied to Figure 4 The terminal in the embodiment of the present application is shown. The specific functions of the processor 602 in this implementation are introduced below.

[0212] The processor 602 is configured to: determine a difference between a first propagation delay and a second propagation delay, where the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to a first satellite, and the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to a second satellite, where the first satellite is a satellite that provides services to the terminal before the terminal is switched, and the second satellite is a satellite that provides services to the terminal after the terminal is switched; and when the difference is greater than a second threshold, send second indication information through the interface circuit 601, where the second indication information is used to instruct to reconfigure uplink resources for the terminal.

[0213] In yet another embodiment, the communication device 600 is applied to Figure 4 The access network device in the embodiment of the present application is shown. The specific functions of the processor 602 in this implementation manner are introduced below.

[0214] The processor 602 is configured to: receive, through the interface circuit 601, second indication information sent by the terminal when a difference between the first propagation delay and the second propagation delay is greater than a second threshold, where the second indication information is used to indicate reconfiguration of uplink resources for the terminal, the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to the first satellite, the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to the second satellite, the first satellite is a satellite that provides services to the terminal before the terminal is switched, and the second satellite is a satellite that provides services to the terminal after the terminal is switched; and reconfigure uplink resources for the terminal according to the second indication information.

[0215] The specific functions of the processor 602 can refer to the description of the communication method provided in the above embodiments and examples of the present application, and Figure 5 The specific functional description of the communication device 500 in the embodiment of the present application is shown and will not be repeated here.

[0216] The memory 603 is used to store program instructions and / or data, etc. Specifically, the program instructions may include a program code, and the program code includes a computer operation instruction. The memory 603 may include a RAM, and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. The processor 602 executes the program instructions stored in the memory 603, and uses the data stored in the memory 603 to implement the above functions, thereby realizing the communication method provided in the above embodiment of the present application. The memory 603 can be integrated with the processor 602, or it can be a memory outside the communication device.

[0217] It is understandable that this application Figure 6The memory 603 in can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a ROM, a programmable read-only memory (programmable ROM, PROM), an erasable programmable read-only memory (erasable PROM, EPROM), an electrically erasable programmable read-only memory (electrically EPROM, EEPROM) or a flash memory. The volatile memory can be a RAM, which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (doubledata rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhancedSDRAM, ESDRAM), synchronous connection dynamic random access memory (synchlink DRAM, SLDRAM) and direct memory bus random access memory (direct rambus RAM, DR RAM). It should be noted that memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

[0218] Based on the above embodiments, the embodiments of the present application further provide a computer program product including computer executable instructions. When the computer program product is run, the method provided in the above embodiments is executed.

[0219] Based on the above embodiments, the embodiments of the present application further provide a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a computer, the computer executes the method provided in the above embodiments.

[0220] The storage medium may be any available medium that can be accessed by a computer. For example, but not limited to, a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0221] Based on the above embodiments, an embodiment of the present application further provides a chip, which is used to read a computer program stored in a memory to implement the method provided in the above embodiments.

[0222] Based on the above embodiments, the embodiments of the present application provide a chip system, which includes a processor for supporting a computer device to implement the functions involved in each device in the above embodiments. In a possible design, the chip system also includes a memory for storing the necessary programs and data for the computer device. The chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0223] In the various embodiments of the present application, unless otherwise specified or provided for in any logical conflict, the terms and / or descriptions between the different embodiments are consistent and may be referenced to each other, and the technical features in the different embodiments may be combined to form new embodiments according to their inherent logical relationships.

[0224] The present application is described with reference to the flowchart and / or block diagram of the method, device (system), and computer program product according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the process and / or box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the function specified in one process or multiple processes in the flowchart and / or one box or multiple boxes in the block diagram.

[0225] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0226] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0227] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship. In the formula of this application, the character " / " can represent a division sign.

[0228] It is understood that the various numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic.

[0229] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: Applied to terminals, including: receiving first indication information from a first cell corresponding to a first satellite, where the first indication information is used to instruct the terminal to perform uplink synchronization with a second satellite without triggering a random access process; After the terminal is in the coverage of the second satellite, if the first synchronization signal and physical broadcast channel PBCH block SSB and the second SSB are the same, uplink synchronization with the second satellite is performed without triggering a random access process, and the first SSB is used for communication between the terminal and the first satellite, and the second SSB is used for communication between the terminal and the second satellite.

2. The method according to claim 1, characterized in that The method performs uplink synchronization with the second satellite by not triggering a random access process, comprising: If the signal quality of the second SSB is greater than the first threshold, uplink synchronization with the second satellite is performed without triggering a random access process.

3. The method according to claim 2, characterized in that Also includes: After the terminal is in the coverage of the second satellite, if the first SSB is the same as the second SSB and the signal quality of the second SSB is less than or equal to the first threshold, uplink synchronization is performed with the second satellite through a random access process.

4. The method according to claim 1 or 2, characterized in that: Also includes: receiving resource configuration information of a second cell corresponding to the first cell or the second satellite, where the resource configuration information is used to configure uplink resources; After the terminal is in the coverage of the second satellite, if the first SSB is the same as the second SSB and the signal quality of the second SSB is less than or equal to a first threshold, a message is sent to the second cell through the uplink resources.

5. The method according to claim 1 or 2, characterized in that: Also includes: After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, uplink synchronization is performed with the second satellite through a random access process.

6. The method according to claim 1 or 2, characterized in that: Also includes: receiving resource configuration information of a second cell corresponding to the first cell or the second satellite, where the resource configuration information is used to configure uplink resources; After the terminal is in the coverage of the second satellite, if the first SSB and the second SSB are different, a message is sent to the second cell through the uplink resources.

7. The method according to claim 4 or 6, characterized in that Also includes: Information indicating the second SSB is sent to the second cell via the uplink resources.

8. The method according to any one of claims 1 to 7, characterized in that A second cell corresponding to the second satellite has a cell identifier that is the same as or different from that of the first cell.

9. A communication method, characterized in that: Applied to terminals, including: determining a difference between a first propagation delay and a second propagation delay, wherein the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to a first satellite, and the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to a second satellite, wherein the first satellite is a satellite providing service to the terminal before the terminal is switched, and the second satellite is a satellite providing service to the terminal after the terminal is switched; In a case where the difference is greater than a second threshold, second indication information is sent, where the second indication information is used to instruct reconfiguration of uplink resources for the terminal.

10. The method according to claim 9, characterized in that The second indication information includes the difference.

11. The method according to claim 9 or 10, characterized in that Determining a difference between a first propagation delay and a second propagation delay includes: Predicting a difference between the first propagation delay and the second propagation delay at at least one of the following times: The time when the first satellite stops providing services for the terminal, the time when the second satellite starts providing services for the terminal, and the time when the terminal accesses the second satellite.

12. A communication method, characterized in that: Applied to access network equipment, including: receiving second indication information sent by a terminal when a difference between a first propagation delay and a second propagation delay is greater than a second threshold, where the second indication information is used to instruct to reconfigure uplink resources for the terminal, the first propagation delay is a propagation delay of a service link between the terminal and a first cell corresponding to a first satellite, the second propagation delay is a propagation delay of a service link between the terminal and a second cell corresponding to a second satellite, the first satellite is a satellite providing service to the terminal before the terminal is switched, and the second satellite is a satellite providing service to the terminal after the terminal is switched; Reconfigure uplink resources for the terminal according to the second indication information.

13. The method according to claim 12, characterized in that The second indication information includes the difference.

14. The method according to claim 12 or 13, characterized in that The difference is the difference between the first propagation delay and the second propagation delay at at least one of the following moments: The time when the first satellite stops providing services for the terminal, the time when the second satellite starts providing services for the terminal, and the time when the terminal accesses the second satellite.

15. A communication device, characterized in that: include: An interface unit for receiving and sending information; A processing unit, configured to execute the method according to any one of claims 1 to 14 through the interface unit.

16. A communication device, characterized in that: The method comprises a processor configured to execute the method according to any one of claims 1 to 14.

17. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 14 is implemented.

18. A computer program product, characterized in that The computer program product comprises: a computer program code, and when the computer program code is executed, the method according to any one of claims 1 to 14 is implemented.

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