A communication method, a communication device, a storage medium, and a communication system

Abstract

The application provides a communication method, a communication device, a storage medium and a communication system, and belongs to the technical field of communication. In the method, in the case of GNSS failure, a terminal device sends a GNSS failure indication and / or first state information of the terminal device to a network device; the network device determines a TA adjustment strategy based on the GNSS failure indication and / or the first state information, and sends a first TA adjustment indication corresponding to the TA adjustment strategy to the terminal device; the terminal device determines the TA of uplink transmission according to the first TA adjustment indication; wherein the network device is a device in an NTN, the first state information is determined based on the real-time moving speed of the terminal device, and the TA adjustment strategy is a conventional compensation TA or an enhanced compensation TA. The network device can make differentiated TA adjustment decisions according to the actual situation of the terminal device, so that the terminal device can still maintain stable and reliable connection with the network in the case of GNSS failure.

Description

Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a communication method, communication device, storage medium, and communication system. Background Technology

[0002] Non-terrestrial network (NTN) communication refers to the use of airborne platforms (such as satellites) located above the ground as communication nodes or relays to connect with ground terminal equipment or networks, thereby achieving wide-area, seamless wireless communication coverage. In NTN networks, due to the significant and rapidly changing transmission delay caused by the high-speed movement of satellites, terminal equipment can be equipped with a Global Navigation Satellite System (GNSS) to calculate and compensate for uplink timing advance (TA) based on the precise position and time information provided by GNSS. This ensures that the transmitted signal is correctly aligned with the receiving time slot of the network equipment, maintaining uplink synchronization.

[0003] However, in actual deployment, GNSS may fail due to reasons such as entering obstructed areas, interference, or receiver failure, which will affect the TA of the terminal device to compensate for the uplink and thus affect the connection between the terminal device and the network device. Summary of the Invention

[0004] This application provides a communication method, communication device, storage medium, and communication system that enable terminal equipment to maintain a stable and reliable connection with network equipment even when GNSS fails.

[0005] Firstly, a communication method is provided. This method can be executed by a terminal device, or by a component (such as a circuit, chip, or chip system) configured in the terminal device, or by a logic module or software capable of implementing all or part of the functions of the terminal device. This application does not limit this approach. The following description uses a terminal device as an example.

[0006] The method includes: in the event of GNSS failure, a terminal device sends a GNSS failure indication and / or first status information of the terminal device to a network device; the terminal device receives a first TA adjustment indication sent by the network device; and the terminal device determines the TA for uplink transmission based on the first TA adjustment indication. Wherein, the network device is a device in an NTN, the first status information is determined based on the real-time movement speed of the terminal device, the first status information is used to indicate the TA drift risk of the terminal device in the event of GNSS failure, different first TA adjustment indications are used to indicate different TA adjustment strategies, the TA adjustment strategy is determined by the network device based on the GNSS failure indication and / or the first status information, and the TA adjustment strategy is either conventional compensation TA or enhanced compensation TA.

[0007] In one implementation, the terminal device may send only a GNSS failure indication to the network device. In this case, the network device may determine the TA adjustment strategy based solely on the GNSS failure indication. In another implementation, the terminal device may send only first status information to the network device. In this case, the network device may determine the TA adjustment strategy based solely on the first status information. In yet another implementation, the terminal device may send both a GNSS failure indication and the first status information to the network device. In this case, the network device may determine the TA adjustment strategy based on both the GNSS failure indication and the first status information simultaneously.

[0008] Conventional compensation TA refers to the adjustment of the TA of terminal devices by network devices and terminal devices using existing, standardized closed-loop control procedures. Therefore, conventional compensation TA has lower signaling overhead but limited compensation capability. Enhanced compensation TA, on the other hand, refers to a set of enhanced compensation procedures initiated by network devices and terminal devices when conventional compensation TA can no longer effectively cope with the situation. Therefore, enhanced compensation TA has higher signaling overhead but stronger compensation capability.

[0009] In the above scheme, when GNSS fails, the terminal device reports a GNSS failure indication and / or first state information determined based on real-time movement speed. This enables the network device to make differentiated TA adjustment decisions based on the actual situation of the terminal device, thus ensuring that the terminal device can maintain a stable and reliable connection with the network even in the event of GNSS failure. Compared with existing technologies where the terminal device immediately switches to enhanced compensation measures in the event of GNSS failure, this scheme, through intelligent collaboration between the terminal device and the network device, can flexibly select between conventional compensation TA and enhanced compensation TA to compensate for the uplink TA. This ensures that the UE can maintain a stable and reliable connection with the network even after losing GNSS assistance, while reducing unnecessary signaling overhead and achieving an optimized balance between performance and efficiency.

[0010] In one possible implementation, the communication method provided in this application further includes: the terminal device acquiring real-time movement speed and calculating the predicted drift rate of the terminal device based on the real-time movement speed; the terminal device determining first state information based on the predicted drift rate. Here, the predicted drift rate refers to the maximum possible rate of change of the TA (Transient Aspect) predicted by the terminal device based on its own real-time movement speed after GNSS failure. It is a pessimistic estimate, providing a conservative upper bound for the TA drift rate of the terminal device. Furthermore, after obtaining the aforementioned first state information, the terminal device can send the first state information to the network device; that is, the terminal device can send only the first state information, or it can send both the first state information and the GNSS failure indication.

[0011] In the above scheme, the terminal device calculates and reports the predicted drift rate based on the real-time movement speed. On the one hand, this provides a more refined basis for the network device to make decisions on the TA adjustment strategy. On the other hand, it also reduces the overhead of the network device in blindly testing the movement status of the terminal device, and improves the real-time performance and accuracy of the status judgment.

[0012] In one possible implementation, if the predicted drift rate of the terminal device is less than the maximum compensation threshold of the network device, the TA adjustment strategy is to compensate the TA in a conventional manner. Here, the maximum compensation threshold is the maximum drift rate that the network device can compensate for through a timing advance command (TAC), meaning the maximum compensation threshold represents the network device's maximum compensation capability for the TA drift rate of the terminal device.

[0013] In the above scheme, if the predicted drift rate is less than the maximum compensation threshold, it means that the maximum compensation capability of the network device can cover the TA drift rate of the terminal device. Therefore, conventional compensation TA can be directly adopted, thereby reducing signaling overhead.

[0014] In one possible implementation, if the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device but less than the enhanced compensation threshold of the network device, and the actual drift rate of the terminal device is less than the maximum compensation threshold, then the TA adjustment strategy is conventional TA compensation. The actual drift rate is determined based on the sounding reference signal (SRS) sent by the terminal device, representing the actual TA drift rate of the terminal device.

[0015] In the above scheme, if the predicted drift rate is greater than the maximum compensation threshold, it means that the TA drift rate of the terminal device may exceed the maximum compensation capability of the network device. However, considering that the predicted drift rate is a pessimistic estimate, if the predicted drift rate is less than the enhanced compensation threshold of the network device, it means that the actual drift rate of the terminal device may still be within the maximum compensation range of the network device. Therefore, it can be further verified by combining the actual drift rate of the terminal device, effectively preventing over-decision caused by the pessimistic estimation of the terminal device. Furthermore, if the actual drift rate is less than the maximum compensation threshold, it means that the maximum compensation capability of the network device can cover the TA drift rate of the terminal device. Therefore, conventional TA compensation can still be used to reduce signaling overhead.

[0016] In one possible implementation, if the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device but less than the enhanced compensation threshold of the network device, and the actual drift rate of the terminal device is greater than the maximum compensation threshold of the network device, then the TA adjustment strategy is enhanced compensation TA.

[0017] In the above scheme, as mentioned earlier, if the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device but less than the enhanced compensation threshold of the network device, it means that the actual drift rate of the terminal device may still be within the maximum compensation range of the network device. Therefore, it can be further verified by combining the actual drift rate of the terminal device, effectively preventing over-decision caused by pessimistic estimation of the terminal device. Furthermore, if the actual drift rate is greater than the maximum compensation threshold, it means that the maximum compensation capability of the network device cannot cover the TA drift rate of the terminal device. Therefore, enhanced compensation for TA can be adopted to ensure the uplink synchronization reliability and prevent connection interruption caused by TA drift accumulation.

[0018] In one possible implementation, if the predicted drift rate of the terminal device is greater than the enhancement compensation threshold of the network device, the TA adjustment strategy is to enhance the TA. Here, the enhancement compensation threshold is a higher threshold than the maximum compensation threshold, used to handle non-worst-case scenarios.

[0019] In the above scheme, if the predicted drift rate of the terminal device is greater than the enhancement compensation threshold of the network device, it means that the maximum compensation capability of the network device cannot cover the TA drift rate of the terminal device even after enhancement. Therefore, enhanced TA compensation can be adopted to ensure the uplink synchronization reliability and prevent connection interruption caused by TA drift accumulation.

[0020] In one possible implementation, the enhanced compensation threshold is equal to the product of the maximum compensation threshold and the safety margin. The safety margin is a predetermined parameter greater than 1, used to reasonably amplify the maximum compensation threshold.

[0021] In the above scheme, by introducing a safety margin, a buffer is provided for the network device's decision-making to deal with non-worst-case situations, thereby increasing the robustness of risk judgment and avoiding unnecessary compensation strategy switching or signaling triggering due to overly strict threshold settings. For example, when the network device's compensation capability can cover the TA drift rate of the terminal device, the TA adjustment strategy is switched from regular compensation TA to enhanced compensation TA, and a first TA adjustment instruction corresponding to the enhanced compensation TA is sent.

[0022] In one possible implementation, if only a GNSS failure indication is sent and the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, then the TA adjustment strategy is conventional compensation TA, where the actual drift rate is determined based on the SRS sent by the terminal device. However, in the scenario where the terminal device only sends a GNSS failure indication, the terminal device may not support self-evaluation of the first state information and therefore cannot send the first state information to the network device; or, although the terminal device supports self-evaluation of the first state information, it may not send the first state information to the network device.

[0023] In the above scheme, network devices actively measure their SRS signals to obtain the actual drift rate and compare it with their maximum compensation capability. This allows terminal devices to enjoy differentiated processing even if they do not send first state information, avoiding the resource waste caused by uniformly applying enhanced compensation. Specifically, if the actual drift rate is less than the maximum compensation threshold, it means that the network device's maximum compensation capability can cover the terminal device's TA drift rate, thus allowing for conventional TA compensation and reducing signaling overhead.

[0024] In one possible implementation, if only a GNSS failure indication is sent and the actual drift rate of the terminal device is greater than the maximum compensation threshold of the network device, then the TA adjustment strategy is to enhance the compensation TA, where the actual drift rate is determined based on the SRS sent by the terminal device.

[0025] In the above scheme, if the actual drift rate is greater than the maximum compensation threshold, it means that the maximum compensation capability of the network device cannot cover the TA drift rate of the terminal device. Therefore, enhanced TA compensation can be adopted to ensure the uplink synchronization reliability and prevent connection interruption caused by TA drift accumulation.

[0026] In one possible implementation, the conventional compensation TA is: the terminal device adjusts the TA based on the TAC sent by the network device.

[0027] In the above scheme, if the maximum compensation capability of the network device can cover the TA drift rate of the terminal device, the terminal device can directly adjust the TA based on the TAC sent by the network device, thereby reducing signaling overhead.

[0028] In one possible implementation, the enhanced TA compensation includes at least one of the following compensation methods: the terminal device adjusts the TA based on the TAC sent by the network device, wherein the period of the network device sending the TAC in the enhanced TA compensation is shorter than the period of the network device sending the TAC in the conventional TA compensation; the terminal device adjusts the TA according to the actual drift rate and the initial compensation value, wherein the initial compensation value is determined by the terminal device based on the last GNSS position; the terminal device adjusts the TA according to the actual position of the terminal device, wherein the actual position is determined by the terminal device using neighboring satellites.

[0029] In the above scheme, the enhanced compensation TA provides a variety of optional enhanced compensation methods, including increasing the TAC issuance frequency, assisting terminal pre-compensation, and providing assisted positioning. This combinatorial enhancement strategy enables network devices to flexibly select compensation methods according to the actual risk level of terminal devices and scenario conditions, ensuring synchronization performance while taking into account signaling efficiency and network load.

[0030] In one possible implementation, the communication method provided in this application embodiment further includes: the terminal device monitoring its own speed changes; if the speed changes cause a change in the first state information, the terminal device sends the second state information to the network device.

[0031] In the above scheme, by continuously monitoring the speed changes of terminal devices and actively updating and reporting when the status changes, the network devices' understanding of the terminal devices' status is always up-to-date. Especially when the terminal devices experience significant speed fluctuations, the TA adjustment strategy can be adjusted in a timely manner, effectively reducing decision-making errors or performance degradation caused by information lag.

[0032] In one possible implementation, the first TA adjustment indication is carried in the radio resource control (RRC) signaling.

[0033] In the above scheme, by carrying the first TA adjustment indication in RRC signaling, the reliability of indication information transmission is improved while reducing signaling overhead.

[0034] Secondly, a communication method is provided, which can be executed by a network device, or by a component (such as a circuit, chip, or chip system) configured in the network device, or by a logic module or software capable of implementing all or part of the functions of the network device. This application does not limit this. The following description uses a network device (such as a satellite) as an example.

[0035] The method includes: a network device receiving a GNSS failure indication and / or first status information of the terminal device sent by a terminal device; the network device determining a timing advance (TA) adjustment strategy based on the GNSS failure indication and / or the first status information of the terminal device; and the network device sending a first TA adjustment indication corresponding to the TA adjustment strategy to the terminal device. Wherein, the network device is a device in an NTN, the first status information is determined based on the real-time movement speed of the terminal device, the first status information is used to indicate the TA drift risk of the terminal device in the event of GNSS failure, and the TA adjustment strategy is either conventional compensated TA or enhanced compensated TA.

[0036] In one implementation, the network device may receive only the GNSS failure indication sent by the terminal device. In this case, the network device may determine the TA adjustment strategy based solely on the GNSS failure indication. In another implementation, the network device may receive only the first status information sent by the terminal device. In this case, the network device may determine the TA adjustment strategy based solely on the first status information. In yet another implementation, the network device may receive both the GNSS failure indication and the first status information sent by the terminal device. In this case, the network device may determine the TA adjustment strategy based on both the GNSS failure indication and the first status information simultaneously.

[0037] In the above scheme, by receiving a GNSS failure indication and / or first state information determined based on the real-time moving speed of the terminal device in the event of GNSS failure, the network device can make differentiated TA adjustment decisions according to the actual situation of the terminal device. This ensures that the terminal device can maintain a stable and reliable connection with the network even in the event of GNSS failure. Compared with the prior art where the terminal device immediately switches to enhanced compensation measures in the event of GNSS failure, this scheme, through intelligent collaboration between the terminal device and the network device, can flexibly select between conventional compensation TA and enhanced compensation TA to compensate for the uplink TA. This ensures that the UE can maintain a stable and reliable connection with the network even after losing GNSS assistance, while reducing unnecessary signaling overhead and achieving an optimized balance between performance and efficiency.

[0038] In one possible implementation, the timing advance (TA) adjustment strategy is determined based on the GNSS failure indication and / or the first state information of the terminal device. This includes: if the first state information is received and indicates that the predicted drift rate of the terminal device is less than the maximum compensation threshold of the network device, then the network device determines the TA adjustment strategy to be conventional TA compensation. Here, the maximum compensation threshold is the maximum drift rate that the network device can compensate for through TA, meaning the maximum compensation threshold represents the network device's maximum compensation capability for the TA drift rate of the terminal device.

[0039] In the above scheme, when the network device determines that its predicted drift rate is less than its maximum compensation capacity based on the information reported by the terminal device, it can directly use the conventional compensation TA, thereby reducing signaling overhead.

[0040] In one possible implementation, the timing advance (TA) adjustment strategy is determined based on GNSS failure indication and / or the first state information of the terminal device, including: if the first state information is received and the first state information indicates that the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device and less than the enhanced compensation threshold of the network device, then the network device determines the actual drift rate corresponding to the terminal device by continuously measuring the SRS sent by the terminal device; if the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, then the network device determines the TA adjustment strategy as conventional compensation TA; otherwise, the network device determines the TA adjustment strategy as enhanced compensation TA.

[0041] In the above scheme, when the network device determines that the predicted drift rate is greater than its maximum compensation capacity based on the information reported by the terminal device, considering that the predicted drift rate is a pessimistic estimate, it can be further verified by combining it with the actual drift rate of the terminal device, effectively preventing over-decision caused by the pessimistic estimation of the terminal device. When the network device determines that the actual drift rate of the terminal device is less than its maximum compensation capacity, it can directly use conventional compensation TA, thereby reducing signaling overhead. When the network device determines that the actual drift rate of the terminal device is greater than its maximum compensation capacity, it can use enhanced compensation TA, thereby ensuring the uplink synchronization reliability and preventing connection interruption caused by the accumulation of TA drift.

[0042] In one possible implementation, after sending a first TA adjustment indication corresponding to the TA adjustment strategy to the terminal device, the method further includes: the network device periodically determining the actual drift rate by continuously measuring the SRS; if the actual drift rate changes from a state less than the maximum compensation threshold to a state greater than the maximum compensation threshold, the network device sends a second TA adjustment indication to the terminal device. The second TA adjustment indication is used to indicate that the TA adjustment strategy is enhanced compensation TA.

[0043] In the above scheme, by periodically checking the actual drift rate of the terminal, the network device can dynamically monitor the status changes of the terminal device. Once it is found that the TA drift rate exceeds its maximum compensation capacity, the compensation strategy can be upgraded in a timely manner, thereby reducing the implicit accumulation of TA error and improving the long-term stability of the connection.

[0044] In one possible implementation, determining the timing advance (TA) adjustment strategy based on the GNSS failure indication and / or the first state information of the terminal device includes: if the first state information is received and the first state information indicates that the predicted drift rate of the terminal device is greater than the enhancement compensation threshold of the network device, then the TA adjustment strategy is determined to be enhancement compensation TA.

[0045] In the above scheme, when the network device determines that its predicted drift rate is greater than the enhancement compensation threshold based on the information reported by the terminal device, it can use enhanced compensation TA to ensure the uplink synchronization reliability and prevent connection interruption caused by TA drift accumulation.

[0046] In one possible implementation, the enhanced compensation threshold is equal to the product of the maximum compensation threshold and the safety margin.

[0047] In the above scheme, by introducing a safety margin, a buffer is provided for the network device's decision-making to deal with non-worst-case situations, thereby increasing the robustness of risk assessment and avoiding unnecessary compensation policy switching or signaling triggering due to overly strict threshold settings.

[0048] In one possible implementation, if only a GNSS failure indication is received, a timing advance (TA) adjustment strategy is determined based on the GNSS failure indication and / or the first state information of the terminal device. This includes: the network device determining the actual drift rate corresponding to the terminal device by continuously measuring the SRS sent by the terminal device; if the actual drift rate is less than the maximum compensation threshold of the network device, the network device determines the TA adjustment strategy as conventional compensation TA; otherwise, the network device determines the TA adjustment strategy as enhanced compensation TA.

[0049] In the above scheme, network devices actively measure their SRS signals to obtain the actual drift rate and compare it with their maximum compensation capability. This allows terminal devices to enjoy differentiated processing even if they do not send first state information, avoiding the resource waste caused by applying enhanced compensation to all devices. Specifically, when the network device determines that the actual drift rate of the terminal device is less than its maximum compensation capability, it can use conventional compensation TA, thereby reducing signaling overhead. When the network device determines that the actual drift rate of the terminal device is greater than its maximum compensation capability, it can use enhanced compensation TA, thereby ensuring uplink synchronization reliability and preventing connection interruptions caused by accumulated TA drift.

[0050] In one possible implementation, the conventional compensation TA is: the terminal device adjusts the TA based on the TAC sent by the network device.

[0051] In the above scheme, if the maximum compensation capability of the network device can cover the TA drift rate of the terminal device, the terminal device can directly adjust the TA based on the TAC sent by the network device, thereby reducing signaling overhead.

[0052] In one possible implementation, the enhanced TA compensation includes at least one of the following compensation methods: the terminal device adjusts the TA based on the TAC sent by the network device, wherein the period of the network device sending the TAC in the enhanced TA compensation is shorter than the period of the network device sending the TAC in the conventional TA compensation; the terminal device adjusts the TA according to the actual drift rate and the initial compensation value, wherein the initial compensation value is determined by the terminal device based on the last GNSS position; the terminal device adjusts the TA according to the actual position of the terminal device, wherein the actual position is determined by the terminal device using neighboring satellites.

[0053] In the above scheme, the enhanced compensation TA provides a variety of optional enhanced compensation methods, including increasing the TAC issuance frequency, assisting terminal pre-compensation, and providing assisted positioning. This combinatorial enhancement strategy enables network devices to flexibly select compensation methods according to the actual risk level of terminal devices and scenario conditions, ensuring synchronization performance while taking into account signaling efficiency and network load.

[0054] In one possible implementation, the first TA adjustment indication is carried in the RRC signaling.

[0055] In the above scheme, by carrying the first TA adjustment indication in RRC signaling, the reliability of indication information transmission is improved while reducing signaling overhead.

[0056] The second aspect is the implementation on the network device side, which corresponds to the first aspect. The explanations, supplements, and descriptions of the beneficial effects of the first aspect also apply to the second aspect, and will not be repeated here.

[0057] Thirdly, a communication device is provided, comprising: a module for performing the methods of any one of the first to second aspects, such as a transceiver module and a processing module. The transceiver module is used to instruct the transceiver functions of the communication device, and the processing module is used to perform functions of the communication device other than the transceiver functions.

[0058] In an optional implementation, the transceiver module may include a sending module and a receiving module. The sending module implements the sending function of the communication device of the third aspect, and the receiving module implements the receiving function of the communication device of the third aspect.

[0059] Furthermore, the technical effects of the communication device in the third aspect can be referenced from the technical effects of any of the implementation methods in the first to second aspects, and will not be elaborated here.

[0060] Fourthly, another communication device is provided, including a processor. This processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the methods in any of the possible implementations of the first to second aspects described above.

[0061] Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, to which the processor is coupled.

[0062] In one implementation, the communication interface can be a transceiver, or an input / output interface.

[0063] In another implementation, the communication device is a chip configured in a terminal device. When the communication device is a chip configured in a terminal device, the communication interface can be an input / output interface.

[0064] Fifthly, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is used to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute a method in any possible implementation of any aspect.

[0065] In specific implementation, the processor can be one or more chips, the input circuit can be input pins, the output circuit can be output pins, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to and transmitted by a transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as both the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0066] In a sixth aspect, a communication device is provided, including a processor and a memory. The processor is used to read instructions stored in the memory and to receive signals via a receiver and transmit signals via a transmitter to execute the method in any possible implementation of any of the above aspects.

[0067] Optionally, the processor may be one or more, and the memory may be one or more.

[0068] In a seventh aspect, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions) that, when the computer program is run, causes a computer to perform a method in any possible implementation of any of the above aspects.

[0069] Eighthly, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when executed on a computer, causes the computer to perform the methods in any possible implementation of any of the preceding aspects.

[0070] In a ninth aspect, a chip system is provided, comprising one or more processors for calling and executing instructions stored in memory, such that the methods in any of the foregoing aspects or any possible implementations of the foregoing aspects are performed. The chip system may be composed of chips or may include chips and other discrete devices.

[0071] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0072] In a tenth aspect, another communication system is provided, including the aforementioned terminal device, first network device, and second network device. Optionally, the communication system may also include other devices that communicate with the terminal device and / or network device. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of a communication system used in an embodiment of this application;

[0074] Figure 2 A schematic diagram showing the locations of different terminal devices in the event of GNSS failure, provided in an embodiment of this application.

[0075] Figure 3 This is a schematic diagram of the TA error corresponding to the mobility of the terminal device provided in the embodiments of this application;

[0076] Figure 4 A schematic diagram illustrating non-linear motion of the terminal device provided in the embodiments of this application;

[0077] Figure 5 A schematic diagram illustrating the first communication method provided in an embodiment of this application;

[0078] Figure 6 A schematic diagram illustrating a second communication method provided in an embodiment of this application;

[0079] Figure 7 This is a schematic diagram of a third communication method provided in an embodiment of this application;

[0080] Figure 8 This is a schematic diagram of the fourth communication method provided in the embodiments of this application;

[0081] Figure 9A schematic diagram illustrating a scenario where the terminal device and network device collaboratively determine the cause of GNSS failure, as provided in an embodiment of this application.

[0082] Figure 10 A schematic diagram illustrating the collaborative determination process between terminal equipment and network equipment in the event of GNSS failure, provided in an embodiment of this application.

[0083] Figure 11 This is a schematic diagram illustrating the signaling interaction between a terminal device and a network device in the event of GNSS failure, provided as an embodiment of this application.

[0084] Figure 12 A schematic diagram illustrating a scenario where a communication method is executed in the event of GNSS failure, as provided in an embodiment of this application.

[0085] Figure 13 A schematic block diagram of a communication device provided in the embodiments of this application;

[0086] Figure 14 Another schematic block diagram of the communication device provided in the embodiments of this application. Detailed Implementation

[0087] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0088] The technical solutions provided in this application can be applied to various communication systems, such as: Global System for Mobile Communications (GSM) systems, General Packet Radio Service (GPRS), Wireless Local Area Network (WLAN), Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, sidelink communication systems, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication systems, NTN communication systems, 5th Generation (5G) mobile communication systems, or new radio access technology (NR). Among these, 5G mobile communication systems can include non-standalone (NSA) and / or standalone (SA) networking. The technical solutions provided in this application can also be applied to future communication systems. This application does not limit the scope of these applications.

[0089] Figure 1 This is a schematic diagram of a communication system used in an embodiment of this application. The communication system 100 may include network devices, such as... Figure 1 The network device 110 is shown. The communication system 100 may also include terminal devices, such as... Figure 1 The terminal device 120 shown. The network device 110 and the terminal device 120 can communicate via a wireless link.

[0090] Figure 1 An exemplary network device 110 and a terminal device 120 are shown. Optionally, the communication system 100 may also include multiple network devices and / or multiple terminal devices.

[0091] In this application, "network equipment" refers to network-side equipment in an NTN network responsible for providing wireless access functionality to terminal devices. For example, in the transparent forwarding mode of satellite communication, the satellite forwards uplink data from the terminal device to the base station (i.e., the gateway or ground station), or forwards downlink data from the base station to the terminal device. In this case, the satellite does not perform encoding / decoding operations; the network equipment is the gateway. In the satellite regeneration mode, some or all of the base station's functions are hosted on the satellite, meaning the satellite performs some or all of the base station's functions, such as encoding / decoding. After receiving uplink data from the terminal device, the satellite performs encoding / decoding operations. In this case, the network equipment is the satellite (or the serving satellite for the terminal device) or a base station located on the satellite.

[0092] In this application, the network device may be referred to as an access network device, which has wireless transceiver capabilities and is used to communicate with terminal devices via an NTN link (satellite link). In this application, the means for implementing the functions of the network device can be the network device itself, or a means capable of supporting the network device in implementing these functions, such as a processor, circuit, chip, or chip system. This means can be installed in the network device or connected to the network device. In the technical solution provided in this application, the example of a network device being used to implement the functions of the network device is used to describe the technical solution provided in this application.

[0093] The terminal device in this application can be a wireless terminal device capable of receiving network device scheduling and instruction information. The wireless terminal device can be a device providing voice and / or data connectivity to a user, a handheld device with wireless connectivity, or other processing devices connected to a wireless modem. For example, the terminal device can communicate with one or more core networks or the Internet via a radio access network (RAN). The terminal device can also be referred to as a terminal, user equipment (UE), mobile station, mobile terminal, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), ultra-reliable low-latency communication (URLLC), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, or satellite communication, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle, aircraft (such as drone, helicopter, airplane), hot air balloon, ship, robot, robotic arm, or smart home device, etc. The embodiments of this application do not limit the form of the terminal device.

[0094] In this application, the apparatus for implementing the functions of a terminal device can be the terminal device itself, or any apparatus capable of supporting the terminal device in implementing those functions, such as a processor, circuit, chip, or chip system. This apparatus can be installed in or connected to the terminal device. In the technical solutions provided in this application, the example of a terminal device being used to implement the functions of a terminal device is used to describe the technical solutions provided in this application.

[0095] Network devices and / or terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. This application does not limit the application scenarios of the network devices and terminal devices. They can be deployed in the same or different scenarios; for example, both network devices and terminal devices can be deployed on land simultaneously; or, network devices can be deployed on land and terminal devices on water, etc., and so on.

[0096] In practical applications, multiple network devices can collaborate to assist terminal devices in achieving wireless access, with different network devices each implementing a portion of the base station's functions. For example, network devices can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0097] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (Open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. CU (or CU-CP and CU-UP), DU, and RU can implement different protocol layer functions.

[0098] There are two scenarios for GNSS failure under NTN: Scenario 1: The terminal device cannot rely on its GNSS to perform timing and frequency compensation for the service link. Scenario 2: The terminal device has a previously acquired GNSS-based location; that is, since the terminal device last acquired its GNSS location, it has not received GNSS information within a time period T, resulting in a decrease in its GNSS accuracy.

[0099] In Scenario 2, a common scenario is that a connected terminal device suddenly experiences a GNSS signal interruption. In this case, the terminal device is forced to rely on its last known GNSS positioning and satellite ephemeris data for self-compensation. Because the terminal device is constantly moving, this compensation method based on static data will generate cumulative errors. These errors increase linearly with the offset of the terminal device from its last known position, eventually manifesting as a rapidly deteriorating TA drift, which directly threatens the synchronization integrity of the uplink.

[0100] In response to this situation, a fundamental problem arises: how to accurately distinguish between normal states and abnormal states requiring enhanced intervention. If this distinction cannot be made effectively, either when GNSS fails, the network side fails to take timely enhancement measures, leading to increased TA drift and subsequent uplink synchronization failure; or under normal circumstances, implementing enhancement measures results in significant signaling overhead and resource waste.

[0101] Currently, existing technologies typically employ a simple reporting mechanism led by the terminal device: upon detecting a GNSS failure, the terminal device immediately reports it, and the network device then switches to GNSS resilient mode and implements immediate enhancement and compensation measures. The advantage of this approach is its simplicity and rapid response, ensuring timely detection and handling of GNSS failure events by the network device. However, this approach has inherent limitations; its core problem lies in its failure to differentiate between the mobile states of the terminal devices.

[0102] Please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the positions of different terminal devices in the event of GNSS failure, provided in an embodiment of this application. Taking an example where both terminal device 1 and terminal device 2 are moving in a straight line: the low-speed terminal device 1 moves at a speed... Move from GNSS failure location Actual position at any given time (distance traveled) ), high-speed terminal equipment 2 at moving speed Move from the GNSS failure location to Actual position at any given time (distance traveled) Due to the moving speed of terminal device 1 The moving speed is less than that of terminal device 2 Therefore, the moving distance of terminal device 1 The distance traveled by terminal device 2 is less than the distance traveled by terminal device 2. .

[0103] In other words, for a low-speed mobile terminal device 1, a conventional compensation strategy may be sufficient to cover its TA drift rate caused by location changes; however, for a high-speed mobile terminal device 2, a conventional compensation strategy may not be able to cover its TA drift rate caused by location changes, thus requiring the activation of an enhanced compensation strategy. However, the simple reporting mechanism in existing technologies, which is driven by the terminal device, activates the enhanced compensation mechanism as soon as the network device receives a GNSS failure report. This introduces unnecessary signaling overhead and resource consumption for a large number of low-speed terminals that do not require special handling.

[0104] In view of this, embodiments of this application provide a communication method in which, in the event of GNSS failure, the terminal device can send a GNSS failure indication and / or the terminal device's first status information to the network device. The network device can then comprehensively assess the current situation based on the information sent by the terminal device and its own compensation capabilities, thereby determining a TA adjustment strategy, instead of immediately switching to the enhanced compensation mechanism upon receiving a GNSS failure report. Therefore, this communication method can reduce unnecessary signaling overhead and achieve an optimized balance between performance and efficiency while ensuring that the terminal device can maintain a stable and reliable connection with the network device even after losing GNSS assistance.

[0105] To facilitate understanding of the embodiments of this application, the terminology used in this application will be briefly explained first. Optionally, the explanation of some terms may also refer to the explanations in the 3rd Generation Partnership Project (3GPP) standard protocol.

[0106] 1. GNSS Failure: Clearly informs network devices that the terminal device has entered GNSS failure mode, and its self-compensation capability is no longer available. GNSS failure of the terminal device can include: the terminal device is not equipped with GNSS, the terminal device's GNSS is (temporarily) unusable, the terminal device's GNSS is usable but the positioning accuracy is below a first threshold, or the terminal device's GNSS is usable but the GNSS measurement period is greater than a second threshold. The first and second thresholds can be set according to actual conditions and are not restricted.

[0107] As mentioned earlier, there are two scenarios for GNSS failure under NTN: Scenario 1 and Scenario 2. Scenario 1 means that the terminal device has never acquired or has completely lost GNSS capability from the beginning and is unable to perform any GNSS-assisted compensation. Scenario 2 means that the terminal device once had reliable GNSS, but the GNSS has not been continuously updated or has not been updated for a long period of time.

[0108] Therefore, GNSS failure can be understood as: the terminal device cannot use GNSS, such as the terminal device not being equipped with GNSS, or the terminal device's GNSS being (temporarily) unusable; or, the terminal device cannot obtain accurate location information based on GNSS. This accurate location information can refer to the TA and / or frequency offset calculated based on the location information meeting the communication requirements of the terminal device and network device. That is, the information provided by the terminal device's GNSS (such as the terminal device's location information) cannot meet the minimum performance requirements necessary to establish or maintain a reliable uplink. For example, the terminal device's GNSS can be used but the positioning accuracy is lower than the first threshold, or the terminal device's GNSS can be used but the GNSS measurement period is greater than the second threshold.

[0109] 2. Network devices in NTN: For example, when the NTN is a satellite network, in the transparent forwarding mode of satellite communication, the network device is a gateway station or a ground station; in the satellite regeneration mode, the network device is the satellite or a base station located on the satellite. The network devices can be referred to the relevant description in the aforementioned communication system section, and will not be repeated here. In the embodiments of this application, the terminal device and the network device communicate through the NTN link.

[0110] 3. GNSS Failure Indication: This is a notification signal generated by the terminal device and actively sent to the network device in the event of GNSS failure. It indicates that the terminal device has lost its ability to rely on GNSS for precise timing and positioning assistance. For example, it can be represented by a 1-bit flag, such as "1" indicating GNSS failure and "0" indicating GNSS validity; alternatively, it can be accompanied by a timestamp or a brief indication of the cause of failure, such as signal termination or accuracy error.

[0111] 4. TA Drift Rate: In the event of GNSS failure, due to the continuous movement of the terminal equipment relative to the satellite, the rate at which the error between the actual required TA and the TA estimated based on the last GNSS position before the failure increases over time. In other words, the TA drift rate is the quotient between the change in TA and time, indicating how many microseconds the TA value will deviate from per second. For example, a TA drift rate of 1.5 μs (microseconds) / s (second) means that if GNSS fails and no compensation is made, then every second, the timing of the uplink transmission by the terminal equipment will lag behind the timing expected by the network equipment by 1.5 microseconds.

[0112] The predicted drift rate is the maximum TA drift rate that a terminal device might experience in the future, estimated by a pre-defined, conservative mathematical model based on its real-time movement speed in the event of GNSS failure. The actual drift rate, on the other hand, is the actual TA drift rate of the terminal device, precisely calculated by the network device through actual measurement of the terminal device's SRS.

[0113] In the event of GNSS failure, the terminal device will perform TA pre-compensation based on the last GNSS position before the failure. However, due to the UE's mobility, there will inevitably be a discrepancy between this TA pre-compensation value and the actual compensation value required. Please refer to... Figure 3 , Figure 3 This is a schematic diagram of the TA error corresponding to the mobility of the terminal device provided in the embodiments of this application. The time is the GNSS failure point. This refers to the duration after GNSS failure. The terminal equipment... The movement continued during the period, but the TA pre-compensation was still based on The position at that moment, therefore. Figure 3 The dashed line on the left represents the predicted distance between the terminal device and the satellite, calculated by the terminal device based on its last GNSS position before failure. Figure 3 The dashed line on the right represents the actual distance between the terminal device and the satellite; the absolute value of the difference in their lengths is the distance estimation error. ; Figure 3 The solid line at the bottom center represents the position estimation error of the terminal device itself. .

[0114] To derive the geometric relationship between distance estimation error and position estimation error, auxiliary lines can be introduced to divide the relevant triangle (a triangle with predicted distance, actual distance, and position estimation error as its three sides) into an isosceles triangle and an obtuse triangle. In this construction, the distance estimation error forms the side adjacent to the obtuse angle of the lower obtuse triangle. Therefore, based on the geometric property that the side opposite the obtuse angle of an obtuse triangle is always greater than its adjacent side, it can be concluded that the distance estimation error is always less than the position estimation error of the terminal device. It should be noted that... Figure 3 The geometric configuration shown is only one possible configuration, but the above conclusions are universal.

[0115] Additionally, please refer to Figure 4 , Figure 4 This is a schematic diagram illustrating the non-linear motion of a terminal device provided in this application embodiment. Regarding the position estimation error of the terminal device, given a terminal device speed... and exercise time Below, it is clear that the position estimation error is largest when the terminal device moves along a straight line; therefore, the upper limit of the position estimation error is... .

[0116] In summary, based on the above two conclusions: 1. The distance estimation error is always less than the position estimation error of the terminal device; 2. The position estimation error is largest when the terminal device moves along a straight line. Therefore, the following chain of inequalities can be derived:

[0117] ;

[0118] in, This indicates the actual drift rate of the terminal device. This represents the distance estimation error, which is the absolute value of the difference between the predicted distance between the terminal device and the satellite calculated by the terminal device based on the last GNSS position before failure and the actual distance between the terminal device and the satellite. This indicates the position estimation error of the terminal device itself. This indicates the real-time moving speed of the terminal device. Represents the speed of light. This represents the predicted drift rate of the terminal device. It can be seen that the estimation results of the terminal device... Always greater than the true value This indicates that the estimation algorithm is essentially a pessimistic estimate, and its result provides a conservative upper bound for the TA drift rate.

[0119] 5. Maximum Compensation Threshold of Network Devices: The maximum drift rate that a network device can compensate for through TAC (Target Acquisition Control), i.e., the maximum compensation capability of a network device to correct TA drift rate. This refers to the maximum rate at which a network device, using its existing closed-loop control mechanism, can correct the TA drift rate of a terminal device in real time. For example, if the maximum compensation threshold of a network device is 1 μs / s, it means that every second, the network device can correct a timing lag or advance of the uplink transmission of the terminal device by 1 microsecond. If the TA drift rate is 1.5 μs / s, then the maximum compensation capability of the network device cannot cover this TA drift rate. Specifically, the network device can estimate its TA drift rate by periodically measuring the SRS (Scheduled Reflection Rate) of the terminal device and then issue TAC for correction. The maximum compensation threshold of the network device can be expressed as:

[0120] ;

[0121] in, This represents the maximum compensation threshold of a network device, i.e., the maximum TA drift rate that the network device can correct. This indicates the maximum amount of TA drift that a network device can correct with a single TAC (Transmission Control Order). This indicates the period during which network devices issue TACs.

[0122] 6. Enhanced Compensation Threshold for Network Devices: Given that the predicted drift rate of terminal devices is a pessimistic estimate, an enhanced compensation threshold is introduced on top of the maximum compensation threshold to address non-worst-case scenarios. This enhanced compensation threshold is greater than the maximum compensation threshold. For example, the enhanced compensation threshold equals the product of the maximum compensation threshold and a safety margin, where the safety margin is a predetermined parameter greater than 1, used to reasonably amplify the maximum compensation threshold. Understandably, the safety margin value can be constrained within a reasonable range, such as greater than 1 and less than 2, thereby avoiding excessively large enhanced compensation thresholds that would require almost all GNSS-failed terminal devices to trigger SRS measurement verification on the network device, leading to high network device overhead.

[0123] As an alternative approach, the security margin value can be determined based on factors such as the mobility statistics of terminal devices, the measurement overhead that network devices can tolerate, and the latency tolerance of services. For example, if the network device mainly serves high-speed terminal devices in scenarios such as high-speed rail and aviation, the security margin can be set to 1.3 to ensure effective capture of these clearly high-risk users; if it mainly serves low-speed terminal devices in scenarios such as walking and low-speed vehicle-mounted devices, the security margin can be set to 1.8 to allow more uncertain terminal devices to enter the verification area and avoid false positives. Furthermore, when network device resources are scarce, the security margin can be set smaller to reduce the number of terminal devices triggering SRS measurement verification and reduce network device resource overhead. It should be understood that the technical terms in this application are for illustrative purposes only and not as limiting factors. For example, as technology evolves, technical terms may also change; where the technical meaning remains the same, other technical terms should also apply to this application.

[0124] The solution provided in this application will be described in detail below with reference to the corresponding flowcharts. It is understood that the illustrative flowcharts provided in this application primarily use different devices (e.g., terminal devices, network devices) as examples of the execution subjects of this interactive illustration to illustrate the method, but this application does not limit the execution subjects of the interactive illustrations. For example, the devices (e.g., terminal devices, network devices) in the illustrative flowcharts can also be chips, chip systems, or processors that support the implementation of this method on the device, or logic modules or software that can implement all or part of the functions of the device.

[0125] It is hereby uniformly stated that the message or signaling interactions involved in the interaction process of the embodiments of this application can adopt standard messages or signaling, or they can be newly introduced messages or signaling. The embodiments of this application do not specifically limit this. The following embodiments are provided as examples to more clearly illustrate the technical solutions of this application, and should not be used to limit the scope of protection of this application. Those skilled in the art will understand that, without conflict, the following embodiments and features can be combined with each other.

[0126] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, relational terms such as "first," "second," etc., in the description of this application are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0127] Furthermore, the term "and / or" in this application is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0128] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "connection" can be a direct connection or an indirect connection through an intermediate medium.

[0129] Please refer to Figure 5 , Figure 5 This is a schematic diagram illustrating a first communication method provided in an embodiment of this application. It can be understood that... Figure 5 The terminal device in the middle can be Figure 1 Any terminal device in the context of network equipment can refer to any component within that terminal device (such as a processor, chip, or chip system). Network equipment can be... Figure 1 Any access network device, or a component within an access network device (such as a processor, chip, or chip system). Figure 5 As shown, the method includes the following steps:

[0130] S201: In the event of GNSS failure, the terminal device sends a GNSS failure indication and / or the terminal device's first status information to the network device; correspondingly, the network device receives the GNSS failure indication and / or the terminal device's first status information sent by the terminal device.

[0131] The first state information of the terminal device is used to indicate the TA drift risk of the terminal device in the event of GNSS failure. The TA drift risk refers to the autonomous assessment data formed by the terminal device by analyzing its own real-time movement speed in the event of GNSS failure, which is used to quantify its uplink synchronization risk and report it to the network device. For example, the first state information can be used to directly indicate the real-time moving speed of the terminal device. Different real-time moving speeds of the terminal device represent different TA drift risk levels. For instance, a real-time moving speed of 10 km / h indicates a low TA drift risk, while a real-time moving speed of 100 km / h indicates a high TA drift risk. Alternatively, different speed ranges can be divided into multiple speed levels, and the first state information can be used to indicate these speed levels. Different speed levels represent different TA drift risk levels. For instance, speeds can be divided into three levels: low speed, medium speed, and high speed. Low speed indicates a low TA drift risk, medium speed indicates a moderate TA drift risk, and high speed indicates a high TA drift risk. Alternatively, the risk level of the terminal device can be determined based on its real-time moving speed. The first state information can be used to indicate these risk levels, and different risk levels represent different TA drift risk levels. For instance, risk levels can include three levels: low risk, medium risk, and high risk. Low risk indicates a low TA drift risk, medium risk indicates a moderate TA drift risk, and high risk indicates a high TA drift risk.

[0132] For example, the first state information can be represented by one or more bits, such as: "1" indicates that the terminal device is in a high-speed state, "0" indicates that the terminal device is in a low-speed state; or, "00" indicates that the terminal device is in a low-risk state, "01" indicates that the terminal device is in a medium-risk state, "10" indicates that the terminal device is in a high-risk state, etc.

[0133] As an optional method, please refer to Figure 6 , Figure 6 This is a schematic diagram of a second communication method provided in an embodiment of this application. The communication method may further include:

[0134] S301: The terminal device acquires the real-time moving speed and calculates the predicted drift rate of the terminal device based on the real-time moving speed.

[0135] The terminal device can estimate its real-time movement speed using internal sensors (e.g., an inertial measurement unit, IMU), and then determine the predicted drift rate based on the estimated real-time movement speed. For example, the terminal device can determine the predicted drift rate based on the following formula:

[0136] ;

[0137] in, This represents the predicted drift rate of the terminal device. This indicates the real-time moving speed of the terminal device. It represents the speed of light.

[0138] It should be noted that S301 described above is executed in the event of GNSS failure. For example, after the terminal device detects a GNSS failure, it begins to execute S301.

[0139] S302: The terminal device determines the first state information based on the predicted drift rate.

[0140] For example, the status of terminal devices can be divided into multiple risk levels based on the predicted drift rate. For instance, terminal devices with a predicted drift rate less than the network device's maximum compensation threshold can be classified as low-risk, while terminal devices with a predicted drift rate greater than the network device's maximum compensation threshold can be classified as high-risk.

[0141] For example, given that the predicted drift rate of the terminal device is a pessimistic estimate, an enhanced compensation threshold can be introduced to address non-worst-case scenarios, thereby classifying the terminal device's state into three risk levels: 1. Terminal devices with a predicted drift rate less than the network device's maximum compensation threshold are classified as low-risk; 2. Terminal devices with a predicted drift rate greater than the network device's maximum compensation threshold but less than the network device's enhanced compensation threshold are classified as medium-risk; 3. Terminal devices with a predicted drift rate greater than the network device's enhanced compensation threshold are classified as high-risk.

[0142] In one implementation, the terminal device may send only a GNSS failure indication to the network device; in another implementation, the terminal device may send only first status information to the network device; and in yet another implementation, the terminal device may send both a GNSS failure indication and first status information to the network device. It is understood that S301-S301 can be executed only when the terminal device needs to send first status information to the network device; that is, if the terminal device only sends a GNSS failure indication to the network device, then S301-S301 need not be executed.

[0143] It should be noted that when a terminal device sends both a GNSS failure indication and a first status information to the network device: the terminal device can send both the GNSS failure indication and the first status information simultaneously through a single signaling message, or it can send them separately through two signaling messages. For example, the terminal device can report the GNSS failure indication and the first status information through uplink RRC signaling (such as RRCReconfigurationComplete or a dedicated new message) or a media access control (MAC) control element (CE); or, the terminal device can report the GNSS failure indication through uplink RRC signaling and report the first status information through a dedicated new message.

[0144] S202: The network device determines the timing advance (TA) adjustment strategy based on the GNSS failure indication and / or the first state information of the terminal device.

[0145] TA adjustment strategy refers to the compensation mechanism determined by network devices based on received terminal information, used to maintain or restore uplink synchronization of the terminal device. In the embodiments of this application, the TA adjustment strategy is either conventional compensation TA or enhanced compensation TA: conventional compensation TA refers to the network device and terminal device adjusting the TA of the terminal device using existing, standardized closed-loop control procedures. Therefore, conventional compensation TA has lower signaling overhead but limited compensation capability; while enhanced compensation TA refers to a set of enhanced compensation procedures initiated by network devices and terminal devices when conventional compensation TA can no longer effectively cope with the situation. Therefore, enhanced compensation TA has higher signaling overhead but stronger compensation capability.

[0146] For example, conventional compensation TA involves the terminal device adjusting its TA based on the TAC (Target Acquisition Code) sent by the network device. Specifically, if the TA adjustment strategy is conventional compensation TA, the network device will maintain the existing TAC issuance mechanism, measuring the terminal device's SRS (Static Resistance Level) at fixed intervals and generating and issuing TACs based on the measurement results. After GNSS failure, the terminal device continues to use the last valid GNSS location for TA pre-compensation, while simultaneously receiving and responding to each TAC issued by the network device, updating its TA according to the adjustment amount in the command. The pre-compensation using the last valid GNSS location can be performed using existing methods.

[0147] For example, the enhanced TA compensation includes at least one of the following compensation methods: First, the terminal device adjusts the TA based on the TAC sent by the network device, wherein the period of the network device sending the TAC in the enhanced TA compensation is shorter than the period of the network device sending the TAC in the conventional TA compensation; Second, the terminal device adjusts the TA according to the actual drift rate and the initial compensation value, wherein the initial compensation value is determined by the terminal device based on its last GNSS position; Third, the terminal device adjusts the TA according to its actual position, wherein the actual position is determined by the terminal device using neighboring satellites.

[0148] Regarding the first compensation method mentioned above (i.e., the terminal device adjusts the TA based on the TAC sent by the network device), if the TA adjustment strategy is enhanced compensation TA, then the network device will shorten the cycle of sending the TAC to the terminal device, for example, shortening the TAC sending cycle to the original cycle. This will improve the compensation capabilities of network devices. This is to enhance the ability to correct the TA drift rate of terminal equipment, enabling it to cover the TA drift rate of the terminal equipment. After GNSS failure, the terminal equipment continues to use the last valid GNSS position for TA pre-compensation, while adjusting the timing expectation of the received TAC, receiving and responding to each TAC issued by the network equipment, and updating its TA according to the adjustment amount in the command.

[0149] For the second compensation method mentioned above (i.e., the terminal device adjusts the TA based on the actual drift rate and the initial compensation value), if the TA adjustment strategy is enhanced compensation TA, the network device can send the calculated actual drift rate to the terminal device; the terminal device adjusts its target compensation value according to the following formula based on the initial compensation value calculated based on the last GNSS position:

[0150] ;

[0151] in, This represents the target compensation value for the terminal device. This represents the initial compensation value calculated by the terminal device based on the last GNSS location. The inertia factor representing smooth drift, This indicates the actual drift rate of the terminal device. This represents the time elapsed from the moment the GNSS failed to the present moment (e.g., the moment when the target compensation value was first calculated, or the moment when the terminal device received the actual drift rate). This compensation method allows the terminal device to autonomously adjust itself based on its past accurate TA drift rate, utilizing its inertia.

[0152] Regarding the third compensation method mentioned above (i.e., the terminal device adjusts its TA based on its actual location), if the TA adjustment strategy is enhanced compensation TA, the network device can utilize other satellites visible to the terminal device to locate it. Specifically, the network device first instructs neighboring satellites to send a positioning reference signal (PRS) to the terminal device so that the terminal device can measure the time delay difference between itself and each satellite. Subsequently, the terminal device uses the downlink TDOA (DL-TDOA) method to calculate its precise location, thereby restoring its autonomous pre-compensation capability.

[0153] Network devices can determine TA adjustment strategies based on GNSS failure indications and / or the first status information of terminal devices. The method by which network devices determine TA adjustment strategies may vary depending on the information sent by the terminal devices (sending only GNSS failure indications, only first status information, or both). The methods by which network devices determine TA adjustment strategies are described in detail below.

[0154] Scenario 1: The terminal device only sends a GNSS failure indication, meaning the network device only receives the GNSS failure indication. Therefore, the network device determines the TA adjustment strategy solely based on the aforementioned GNSS failure indication. For example, the situation where the terminal device only sends a GNSS failure indication may occur in cases where the terminal device can only report a GNSS failure indication, the terminal device cannot determine the first status information, or the terminal device cannot report the first status information.

[0155] It is understood that the embodiments of this application constitute a verification and decision-making process entirely led by the network device. The network device can determine the actual drift rate of the terminal device based on the SRS sent by the terminal device, and then compare the actual drift rate with its own maximum compensation threshold to determine the TA adjustment strategy based on the comparison result. Specifically, if the network device only receives a GNSS failure indication, then the above S202 may specifically include the following steps:

[0156] Step 1), the network device determines the actual drift rate of the terminal device by continuously measuring the SRS sent by the terminal device.

[0157] For example, network devices at any time The network device captures the first SRS sent by the terminal device. Specifically, it can use a correlator to perform matched filtering with the locally stored SRS sequence to measure the propagation time of the SRS from the terminal antenna, through space, and to the network receiving antenna, and convert the propagation time into the corresponding first TA value. Network devices are constantly ( (This represents the time interval between two SRS transmissions.) Capture the second SRS transmitted by the terminal device, repeat the same time measurement procedure, and obtain the second TA value. Network devices can determine the actual drift rate of terminal devices based on the following formula:

[0158] ;

[0159] in, This indicates the actual drift rate of the terminal device. This represents the TA value corresponding to the first SRS. This indicates the TA value corresponding to the second SRS. This indicates the time interval between two SRS transmissions.

[0160] Step 2): If the actual drift rate is less than the maximum compensation threshold of the network device, the network device determines the TA adjustment strategy as conventional TA compensation; otherwise, the network device determines the TA adjustment strategy as enhanced TA compensation.

[0161] If the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, the network device confirms that its compensation capability is sufficient to cover the actual drift rate of the terminal device, and therefore the TA adjustment strategy can be determined to be conventional TA compensation. If the actual drift rate of the terminal device is greater than the maximum compensation threshold of the network device, the network device determines that the actual drift rate of the terminal device has exceeded its compensation capability, and therefore the TA adjustment strategy can be determined to be enhanced TA compensation.

[0162] Since existing terminal devices lack self-evaluation capabilities, all GNSS failure events require triggering SRS measurements and calculations by the network equipment, which necessitates the use of the communication method provided in this application. Although this increases the processing overhead of the network equipment and SRS-related signaling resources, it effectively distinguishes between low-speed and high-speed terminal devices through precise measurements by the network equipment, thereby avoiding unnecessary enhancement compensation for a large number of low-speed terminal devices. This differentiated processing still significantly outperforms existing solutions in terms of overall signaling overhead, thus serving as an effective compatibility solution for traditional terminal devices.

[0163] Scenario 2: The terminal device sends both a GNSS failure indication and first status information; that is, the network device receives both the GNSS failure indication and the first status information. Therefore, the network device can simultaneously determine the TA adjustment strategy based on the aforementioned GNSS failure indication and first status information. For example, if the terminal device can determine the first status information and can report the first status information, the terminal device can send both the GNSS failure indication and the first status information.

[0164] It is understood that this application embodiment is a process of collaborative verification and decision-making between a terminal device and a network device. The terminal device assesses the risk level after GNSS failure based on its real-time movement speed, and then reports the assessment result (i.e., the first status information) to the network device. The network device makes a decision on the TA adjustment strategy based on the data reported by the terminal device and sends it to the terminal device. Specifically, if the network device receives both the GNSS failure indication and the first status information, then the above-mentioned S202 may specifically include the following steps:

[0165] Step 1): If the predicted drift rate of the terminal device represented by the first state information is less than the maximum compensation threshold of the network device, then the network device determines the TA adjustment strategy as conventional compensation TA.

[0166] For example, when a terminal device assesses its predicted drift rate as less than the network device's maximum compensation threshold, it can assess its own state as low risk and determine that the TA drift problem caused by its mobility will not lead to uplink synchronization failure. In this case, the network device's compensation capability is sufficient to cover the terminal device's pessimistic estimate; that is, even if the terminal device moves according to the worst-case scenario, the conventional TA compensation is completely sufficient to compensate for the terminal device's TA drift rate.

[0167] Step 2): If the predicted drift rate of the terminal device represented by the first state information is greater than the maximum compensation threshold of the network device and less than the enhancement compensation threshold of the network device, then the network device determines the actual drift rate corresponding to the terminal device by continuously measuring the SRS sent by the terminal device.

[0168] For example, when a terminal device assesses that its predicted drift rate is greater than the network device's maximum compensation threshold, the terminal device's TA drift rate may exceed the network device's compensation capability. However, considering that the terminal device's predicted drift rate is a pessimistic estimate that is significantly higher than the actual value, its actual drift rate may still be within the network device's compensation capability, i.e., the terminal device's predicted drift rate is less than the network device's enhanced compensation threshold. The terminal device can assess its own status as medium risk, which indicates that there is a potential risk to uplink synchronization. The network device cannot determine that the actual risk has exceeded the limit based solely on this report, and can initiate a verification process for secondary confirmation.

[0169] The verification method is as follows: The terminal device periodically sends SRS (Short Response Signals) for the network device to perform channel measurement and timing estimation. The network device can accurately calculate the TA (Transmission Aspect Ratio) drift rate caused by the actual movement of the terminal by comparing the TA values ​​corresponding to two consecutive SRS measurements. The specific implementation of this verification method has been described in detail in the embodiment corresponding to Case 1 above, and will not be repeated here.

[0170] Step 3): If the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, the network device determines the TA adjustment strategy as conventional TA compensation; otherwise, the network device determines the TA adjustment strategy as enhanced TA compensation.

[0171] If the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, it indicates that the current TA drift rate is within a controllable range, and the previous estimate of the terminal device was overly pessimistic. Therefore, the network device can determine the TA adjustment strategy as conventional TA compensation. If the actual drift rate of the terminal device is greater than the maximum compensation threshold of the network device, it indicates that the compensation capability of the network device is indeed insufficient to cover the actual drift rate of the terminal device. Therefore, the network device can determine the TA adjustment strategy as enhanced TA compensation, providing stronger compensation for the TA drift rate caused by the mobility of the terminal device.

[0172] Step 4): If the predicted drift rate of the terminal device represented by the first state information is greater than the enhancement compensation threshold of the network device, then the TA adjustment strategy is determined to be enhancement compensation TA.

[0173] For example, when a terminal device assesses its predicted drift rate as greater than the network device's enhanced compensation threshold, it can assess its own status as high-risk and determine that there is a serious risk to uplink synchronization. In this case, even if the terminal device's estimate is pessimistic, the terminal device's TA drift rate may still exceed the network device's compensation capability after factoring in the safety margin; that is, the terminal device has extremely high mobility, and even considering the pessimistic estimate, its TA drift rate is very likely to exceed the coverage of the conventionally compensated TA, posing a serious threat to connection quality.

[0174] For example, suppose the maximum compensation threshold of the network device is 2 μs / s (i.e., the network device can correct a maximum TA drift rate of 2 microseconds per second), and the predicted drift rate of the terminal device is 2.1 μs / s: If no safety margin is introduced in the current scenario, since the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device, the network device will determine the TA adjustment strategy as enhanced TA compensation. However, since the predicted drift rate of the terminal device is a pessimistic estimate, its actual drift rate may only be 1.9 μs / s. Therefore, the network device may perform an unnecessary enhanced compensation, resulting in wasted resources. If a safety margin (assumed to be 1.5) is introduced in the current scenario, then the enhancement compensation threshold of the network device is 3μs / s. Although the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device, it is less than the enhancement compensation threshold of the network device. The network device will not directly determine the TA adjustment strategy as enhancement compensation TA, but will further calculate the actual drift rate of the terminal device (assumed to be 1.9μs / s). Since the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, the network device will determine the TA adjustment strategy as regular compensation TA, thus successfully avoiding one overcompensation.

[0175] It should be noted that step 1) in this embodiment is a specific implementation method for the network device to determine the TA adjustment strategy when the terminal device is in a low-risk state; steps 2) and 3) in this embodiment are specific implementation methods for the network device to determine the TA adjustment strategy when the terminal device is in a medium-risk state; and step 4) in this embodiment is a specific implementation method for the network device to determine the TA adjustment strategy when the terminal device is in a high-risk state.

[0176] Scenario 3: The terminal device only sends the first status information, meaning the network device only receives the first status information. Therefore, the network device can determine the TA adjustment strategy based on the aforementioned first status information. For example, if the terminal device has already sent a GNSS failure indication beforehand, the terminal device can send only the first status information.

[0177] The specific implementation of the network device determining the TA adjustment strategy in this application embodiment is similar to the specific implementation of the network device determining the TA adjustment strategy in the embodiment where the terminal device sends both GNSS failure indication and first status information, and will not be repeated here; the only difference between the two is whether the terminal device sends a GNSS failure indication to the network device.

[0178] In other words, for low-speed or even stationary terminal equipment, the position deviation and TA drift caused by GNSS failure are very limited, and conventional TS compensation is sufficient to cope with it, without the need to start enhancement measures; conversely, for high-speed terminal equipment, the TA drift will increase sharply, and it is necessary to rely on enhanced TA compensation.

[0179] S203: The network device sends a first TA adjustment instruction corresponding to the TA adjustment policy to the terminal device; correspondingly, the terminal device receives the first TA adjustment instruction sent by the network device.

[0180] Network devices can generate corresponding control commands (i.e., first TA adjustment instructions) and send them to terminal devices according to the TA adjustment policy determined in S202. Different first TA adjustment instructions are used to indicate different TA adjustment policies. That is, a normal compensation TA corresponds to one type of first TA adjustment instruction, and an enhanced compensation TA corresponds to another type. For example, a first TA adjustment instruction of "normal" indicates that the TA adjustment policy is normal compensation TA, and a first TA adjustment instruction of "enhanced" indicates that the TA adjustment policy is enhanced compensation TA.

[0181] For example, when the TA adjustment strategy is to enhance the TA compensation, the first TA adjustment indication information may include an indication field and specific enhancement parameters, such as: the shortened TAC transmission period, the actual drift rate calculated by the network device, or the location information of the terminal device calculated by the network device based on other satellites, etc.

[0182] As an alternative, the first TA adjustment indication can be carried in the RRC signaling.

[0183] S204: The terminal equipment determines the TA for uplink transmission according to the first TA adjustment instruction.

[0184] If the first TA adjustment indication is used to indicate that the TA adjustment strategy is conventional compensation TA, the terminal device can continue to perform TA pre-compensation based on the last GNSS location and receive and respond to the TAC periodically issued by the network device to determine the TA.

[0185] If the first TA adjustment instruction is used to indicate that the TA adjustment strategy is enhanced compensation TA, the terminal device can adjust its method of determining TA according to the enhancement parameters attached to the first TA adjustment instruction; for example, it can determine TA by receiving and responding to the TAC periodically sent by the network device after shortening the cycle; or, it can superimpose the actual drift rate sent by the network device into the conventional compensation TA method to determine the final TA used for uplink transmission; or, it can determine TA by using the conventional compensation TA method based on the actual position of the terminal device determined by the network device based on other satellites.

[0186] Furthermore, based on the above embodiments, please refer to... Figure 7 , Figure 7 This is a schematic diagram of a third communication method provided in an embodiment of this application. When the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device but less than the enhancement compensation threshold of the network device, after S203 above, the communication method provided in this embodiment may further include:

[0187] S401: Network devices periodically determine the actual drift rate by continuously measuring the SRS.

[0188] S402: If the actual drift rate changes from being less than the maximum compensation threshold to being greater than the maximum compensation threshold, the network device sends a second TA adjustment instruction to the terminal device.

[0189] Considering the dynamic nature of terminal device movement, its current state (i.e., the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device but less than the enhanced compensation threshold of the network device) may not be sustainable. For example, after completing a turn, the terminal device re-enters high-speed straight-line motion, causing the TA drift rate of the terminal device to be lower than the compensation capability of the network device during the turn, while the TA drift rate of the terminal device is higher than the compensation capability of the network device after the turn is completed.

[0190] Therefore, network devices can introduce a periodic review mechanism: set an evaluation period, and at each evaluation period, the network device will remeasure the SRS and calculate the actual drift rate; once it is found that the actual drift rate changes from being less than the maximum compensation threshold to being greater than the maximum compensation threshold, the TA adjustment strategy is determined to be enhanced compensation TA, and the second TA adjustment instruction corresponding to the enhanced compensation TA is sent to the terminal device.

[0191] This periodic review mechanism ensures that network equipment responds quickly to risk escalation and effectively avoids the accumulation of TA errors.

[0192] Understandably, once a network device detects that the actual drift rate changes from being greater than the maximum compensation threshold to being less than the maximum compensation threshold, it can also determine the TA adjustment strategy as the regular compensation TA and send the second TA adjustment instruction corresponding to the regular compensation TA to the terminal device.

[0193] Furthermore, based on the above embodiments, please refer to... Figure 8 , Figure 8 This is a schematic diagram of a fourth communication method provided in an embodiment of this application. The communication method provided in an embodiment of this application may further include:

[0194] S501: The terminal device monitors its own speed changes.

[0195] S502: If the speed change causes a change in the first state information, the terminal device sends the second state information to the network device.

[0196] Also considering the dynamic nature of terminal device movement, the terminal device's own state assessment mechanism can be real-time. Since the terminal device's predicted drift rate is directly related to its real-time movement speed, and the network device's maximum compensation threshold is a fixed value, any significant speed fluctuation of the terminal device (such as emergency braking or sudden acceleration) may lead to a transition in state level.

[0197] Therefore, a real-time status update mechanism can be introduced for terminal devices: during GNSS failure, the terminal device continuously monitors its own speed changes. Once a speed change is detected that triggers a change in status level, the UE should immediately trigger a new status update signaling to reassess and report the latest status. This mechanism ensures that the network's perception of UE risks is synchronized in real time, especially when the UE undergoes severe maneuvers, guaranteeing the accuracy and timeliness of decision-making.

[0198] In summary, within NTN, a large number of connected terminal devices may fail due to GNSS signal loss. These terminal devices exhibit significantly different mobility characteristics, covering a wide range from low-speed (e.g., walking), medium-speed (e.g., vehicle-mounted) to high-speed (e.g., high-speed rail, aviation), such as... Figure 9 As shown. In this context, how to ensure that these terminal devices can maintain a stable and reliable connection with network devices after losing GNSS assistance is the core issue of this application.

[0199] Therefore, in this embodiment, when a GNSS failure is detected, the terminal device can perform a rapid preliminary assessment by combining its own status (such as real-time movement speed) with the compensation capability threshold of the network device, and report the assessment result. Subsequently, the network device utilizes its global information advantage to make a secondary, precise decision based on the status reported by the terminal device, and sends the final instruction to the terminal device to achieve precise synchronization of the states at both ends. Thus, this embodiment organically combines the terminal device's rapid local perception capability with the network device's global, precise decision-making capability, ensuring the accuracy and timeliness of the decision. Simultaneously, by triggering enhanced compensation (TA) only when necessary, unnecessary signaling overhead is significantly reduced, achieving an optimized balance between performance and efficiency.

[0200] For example, please refer to Figure 10 , Figure 10 This is a schematic diagram illustrating the collaborative determination process between a terminal device and a network device in the event of GNSS failure, as provided in an embodiment of this application. Specifically, the collaborative determination process between the terminal device and the network device in the event of GNSS failure may include:

[0201] S601: The terminal device detected a GNSS failure.

[0202] S602: The terminal device assesses its own status based on the compensation capability of the network device (i.e., the maximum compensation threshold) and its own real-time moving speed.

[0203] S603: The terminal device reports its own status through GNSS failure indication and / or first status information.

[0204] S604: The network device receives the GNSS failure indication and / or first status information sent by the terminal device.

[0205] S605: If the terminal device is in a low-risk state (i.e., the predicted drift rate of the terminal device is less than the maximum compensation threshold of the network device), then the network device determines the TA adjustment strategy as normal compensation TA.

[0206] S606: If the terminal device is in a high-risk state (i.e., the predicted drift rate of the terminal device is greater than the enhancement compensation threshold of the network device), then the network device determines the TA adjustment strategy as enhancement compensation TA.

[0207] S607: If the terminal device is in a medium-risk state (i.e., the first state information indicates that the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device and less than the enhancement compensation threshold of the network device), then the network device periodically measures the SRS and calculates the actual drift rate of the terminal device.

[0208] S608: Network devices compare the actual drift rate with their own compensation capabilities.

[0209] S609: If the actual drift rate of the terminal device is lower than the compensation capability (i.e., less than the maximum compensation threshold of the network device), the network device determines the TA adjustment strategy as normal compensation TA.

[0210] S610: Periodic re-inspection of network devices (i.e., recalculating the actual drift rate and comparing the actual drift rate with its own compensation capability).

[0211] S611: If the actual drift rate of the terminal device is higher than the compensation capability (i.e., greater than the maximum compensation threshold of the network device), the network device determines the TA adjustment strategy as enhanced compensation TA.

[0212] S612: The network device feeds back the TA adjustment policy to the terminal device through the first TA adjustment instruction.

[0213] S613: The terminal device takes corresponding measures based on the feedback from the network device.

[0214] For example, please refer to Figure 11 , Figure 11This is a schematic diagram illustrating the signaling interaction between a terminal device and a network device in the event of GNSS failure, as provided in an embodiment of this application. Specifically, when the terminal device detects a GNSS failure, it assesses its own status and reports first status information. The network device receives the first status information and determines a TA adjustment strategy based on it: 1. If the terminal device is in a low-risk state (i.e., the predicted drift rate of the terminal device is less than the maximum compensation threshold of the network device), the network device confirms that it can completely cover the TA drift rate caused by the movement of the terminal device, and then issues a first TA adjustment instruction corresponding to the conventional compensation TA. 2. If the terminal device is in a high-risk state (i.e., the predicted drift rate of the terminal device is greater than the enhanced compensation threshold of the network device), the network device determines that the risk is extremely high, and then issues a first TA adjustment instruction corresponding to the enhanced compensation TA. 3. If the terminal device is in a medium-risk state (i.e., the first status information indicates that the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device and less than the enhanced compensation threshold of the network device), the network device performs a fine assessment of the terminal device's status based on SRS and issues a first TA adjustment instruction corresponding to the assessment result; in addition, the network device can perform periodic reviews. Finally, the terminal equipment takes corresponding measures based on the first TA adjustment instruction.

[0215] Please refer to Figure 12 , Figure 12 This illustration shows a scenario where a communication method is executed in the event of GNSS failure, as provided in this application embodiment. One satellite simultaneously provides services to multiple terminal devices with varying GNSS failures and different movement speeds. The purpose of the communication method provided in this application embodiment is to achieve differentiated and refined management of these terminal devices. Specifically, after GNSS failure, the terminal device first performs a rapid self-assessment based on its real-time movement speed (i.e., calculates its predicted drift rate based on the real-time movement speed and compares the predicted drift rate with the network device's maximum compensation threshold and enhancement compensation threshold). For example, it determines its own risk level and reports this risk level to the network device through first status information. The network device then adopts a differentiated strategy based on the reported first status information: for terminal devices reporting low risk (i.e., ... Figure 12 For terminal devices operating at low speeds: 1) a direct decision can be made, i.e., the TA adjustment strategy can be set to conventional TA compensation; for terminal devices reporting high risks (i.e.... Figure 12 For terminal devices operating at high speeds (3), a direct decision can be made, namely, determining the TA adjustment strategy to enhance and compensate for TA; while for terminal devices reporting medium-risk (i.e., Figure 12 For terminal devices 2 operating at medium speeds, precise verification is performed using SRS measurements before making a decision. For example, the actual drift of the terminal device is calculated based on SRS, and the actual drift rate is compared with its own maximum compensation threshold. Finally, the network device can issue a first TA adjustment instruction corresponding to the determined TA adjustment strategy.

[0216] Therefore, the communication method provided in this application can efficiently coordinate the rapid sensing capability of terminal devices with the precise measurement capability of network devices, ensuring the accuracy of TA drift rate compensation. Simultaneously, by avoiding unnecessary SRS measurements on low-speed terminal devices, it significantly reduces system signaling overhead. Furthermore, considering the complexity of the terminal device's motion state, a hierarchical mechanism with safety margins is introduced, classifying risks into three levels: Low risk: compensation is still possible under the most conservative estimate, and the network device directly determines the risk; High risk: compensation is still impossible even beyond the safety margin, and the network device directly determines the risk; Medium risk: between the two, and the network device initiates refined measurement and evaluation. That is, resource-intensive measurements are only performed when necessary, thereby significantly reducing signaling overhead while maximizing the accuracy of network decisions.

[0217] It should be understood that Figures 5 to 12 The flowcharts or scene diagrams shown are for illustrative purposes only and are not intended to limit the embodiments of this application to the examples illustrated. In fact, those skilled in the art can interpret the embodiments based on... Figures 5 to 12 The examples in the document can be transformed into equivalent ways to obtain more implementations.

[0218] The above text combined Figures 5 to 12 This document describes in detail the communication method provided in the embodiments of this application. The following will combine... Figures 13 to 14 The device embodiments of this application are described in detail below. It should be understood that the communication device of this application embodiment can execute the various communication methods of the foregoing embodiments of this application, that is, the specific working processes of the various products below can be referred to the corresponding processes in the foregoing method embodiments.

[0219] In the embodiments described above, the terminal device may execute some or all of the steps in each embodiment; the network device may execute some or all of the steps in each embodiment. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the steps may be executed in different orders as presented in the embodiments, and it is not necessary to execute all the operations in the embodiments of this application. Moreover, the sequence number of each step does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0220] Figure 13 This is a schematic block diagram of a communication device provided in an embodiment of this application. Figure 13As shown, the communication device 700 may include a communication module 720. The communication module 720 can implement corresponding communication functions, which can be internal communication functions of the communication device 700 or communication functions between the communication device 700 and other devices. Optionally, the communication module 720 may also be referred to as a communication interface or transceiver module. Optionally, the communication device 700 further includes a processing module 710. The processing module 710 can implement corresponding processing functions.

[0221] Optionally, the communication device 700 further includes a storage module, which can be used to store instructions and / or data; the processing module 710 can read the instructions and / or data in the storage module so that the communication device 700 can implement the aforementioned method embodiments.

[0222] In one possible design, the communication device 700 may correspond to the terminal device in the above method embodiments, or to a component (such as a circuit, chip, or chip system) configured in the terminal device. The communication device 700 can be used to perform the steps or processes performed by the terminal device in any of the above method embodiments.

[0223] For example, in the event of GNSS failure, the communication module 720 is configured to send a GNSS failure indication and / or first status information of the terminal device to a network device in a non-terrestrial network connected to the terminal device, wherein the first status information is determined based on the real-time moving speed of the terminal device and is used to indicate the TA drift risk of the terminal device in the event of GNSS failure; and to receive a first timing advance (TA) adjustment indication sent by the network device, wherein different first TA adjustment indications are used to indicate different TA adjustment strategies, the TA adjustment strategy is determined by the network device based on the GNSS failure indication and / or the first status information, and the TA adjustment strategy is either conventional compensated TA or enhanced compensated TA.

[0224] The processing module 710 is used to determine the TA for uplink transmission based on the first TA adjustment instruction.

[0225] The above are merely examples; for detailed steps or procedures, please refer to the descriptions in the foregoing embodiments.

[0226] In one possible design, the communication device 700 may correspond to the network device in the above method embodiments, or to a component (such as a circuit, chip, or chip system) configured in the network device. The communication device 700 can be used to perform the steps or processes performed by the network device in any of the above method embodiments.

[0227] For example, the processing module 710 is used to determine a timing advance (TA) adjustment strategy based on GNSS failure indication and / or first state information of the terminal equipment, wherein the TA adjustment strategy is a conventional compensated TA or an enhanced compensated TA.

[0228] The communication module 720 is used to receive a Global Navigation Satellite System (GNSS) failure indication and / or a first status information of the terminal device sent by a terminal device connected to the network device, wherein the first status information is determined based on the real-time moving speed of the terminal device and is used to indicate the TA drift risk of the terminal device in the event of GNSS failure; and to send a first TA adjustment indication corresponding to the TA adjustment strategy to the terminal device.

[0229] The above are merely examples; for detailed steps or procedures, please refer to the descriptions in the foregoing embodiments.

[0230] Figure 14 This is another schematic block diagram of a communication device provided in an embodiment of this application. The communication device 800 may be a chip, chip system, or processor, etc., in a terminal device or network device that implements the above-described methods. The communication device 800 can be used to implement the methods described in the above-described method embodiments; for details, please refer to the descriptions in the above-described method embodiments.

[0231] like Figure 14 As shown, the communication device 800 may include one or more processors 810, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 810 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the communication device 800 (e.g., a base station, baseband chip, user, user chip), execute software programs, and process data from the software programs.

[0232] In an alternative design, the processor 810 may also store instructions and / or data that can be executed by the processor 810 to cause the communication device 800 to perform the methods described in the above method embodiments.

[0233] In another alternative design, the communication device 800 may include a communication interface 820 for implementing receiving and transmitting functions. For example, the communication interface 820 may be a transceiver circuit, interface, interface circuit, or transceiver. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and transmitting functions may be separate or integrated. The aforementioned transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0234] Optionally, the communication device 800 may include one or more memories 830, which may store instructions that can be executed on the processor 810, causing the communication device 800 to perform the methods described in the above method embodiments. Optionally, the memories 830 may also store data. Optionally, the processor 810 may also store instructions and / or data. The processor 810 and the memories 830 may be provided separately or integrated together.

[0235] It should be understood that, in one possible design, the steps in the method embodiments provided in this application can be implemented by integrated logic circuits in the processor's hardware or by instructions in software form. The steps of the methods disclosed in the embodiments of this application can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0236] In one implementation, the communication device 800 may correspond to the terminal device in the above method embodiments and may be used to execute the various steps and / or processes executed by the terminal device in the above method embodiments. The processor 810 may be used to execute instructions stored in the memory 830, and when the processor 810 executes the instructions stored in the memory, the processor 810 is used to execute the various steps and / or processes of the above method embodiments corresponding to the terminal device.

[0237] In another implementation, the communication device 800 may correspond to the network device in the above method embodiments and may be used to execute the various steps and / or processes executed by the network device in the above method embodiments. The processor 810 may be used to execute instructions stored in the memory 830, and when the processor 810 executes the instructions stored in the memory, the processor 810 is used to execute the various steps and / or processes of the above method embodiments corresponding to the network device.

[0238] It should be understood that the aforementioned processing device can be one or more chips. For example, the processing device can be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system-on-chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0239] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0240] According to the method provided in the embodiments of this application, this application also provides a chip system, which includes one or more processors for calling and executing instructions stored in memory, thereby causing the method described in the embodiments of this application to be executed. The chip system may be composed of chips or may include chips and other discrete devices.

[0241] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0242] According to the method provided in the embodiments of this application, this application also provides a communication system, which includes the aforementioned network device and terminal device.

[0243] According to the method provided in the embodiments of this application, this application also provides a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the network device or terminal device in any of the foregoing method embodiments.

[0244] According to the method provided in the embodiments of this application, this application also provides a computer-readable storage medium storing program code, which, when run on a computer, causes the computer to execute the various steps or processes executed by the network device or terminal device in any of the foregoing method embodiments.

[0245] The computer-readable storage medium may be the aforementioned volatile memory or non-volatile memory, or it may include both volatile memory and non-volatile memory.

[0246] In the embodiments of this application, the terms and English abbreviations are exemplary examples given for ease of description and should not be construed as limiting the application in any way. This application does not preclude the possibility of defining other terms that can achieve the same or similar functions in existing or future agreements.

[0247] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated.

[0248] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

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

[0250] In summary, the above description is merely a preferred embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, Applied to terminal devices, including: In the event of a GNSS failure, a GNSS failure indication and / or first status information of the terminal device are sent to network devices in a non-terrestrial network connected to the terminal device. The first status information is determined based on the real-time moving speed of the terminal device and is used to indicate the timing advance (TA) drift risk of the terminal device in the event of a GNSS failure. The network device receives a first TA adjustment instruction, wherein different first TA adjustment instructions are used to indicate different TA adjustment strategies. The TA adjustment strategy is determined by the network device based on the GNSS failure indication and / or the first status information. The TA adjustment strategy is either conventional compensated TA or enhanced compensated TA. The TA for uplink transmission is determined based on the first TA adjustment instruction; If only the GNSS failure indication is sent, the TA adjustment strategy is determined based on the comparison between the actual drift rate of the terminal device and the maximum compensation threshold of the network device. The actual drift rate is determined based on the sounding reference signal (SRS) sent by the terminal device, and the maximum compensation threshold is the maximum drift rate that the network device can compensate for by using a timed advance command (TAC).

2. The method according to claim 1, characterized in that, The method further includes: The real-time moving speed is obtained, and the predicted drift rate of the terminal device is calculated based on the real-time moving speed; The first state information is determined based on the predicted drift rate.

3. The method according to claim 2, characterized in that, If the predicted drift rate is less than the maximum compensation threshold of the network device, then the TA adjustment strategy is the conventional compensation TA; Alternatively, if the predicted drift rate is greater than the maximum compensation threshold and less than the enhanced compensation threshold of the network device, and the actual drift rate of the terminal device is less than the maximum compensation threshold, then the TA adjustment strategy is the conventional compensation TA.

4. The method according to claim 2, characterized in that, If the predicted drift rate is greater than the maximum compensation threshold of the network device and less than the enhanced compensation threshold of the network device, and the actual drift rate of the terminal device is greater than the maximum compensation threshold, then the TA adjustment strategy is the enhanced compensation TA. Alternatively, if the predicted drift rate is greater than the enhancement compensation threshold, then the TA adjustment strategy is the enhancement compensation TA.

5. The method according to claim 3 or 4, characterized in that, The enhanced compensation threshold is equal to the product of the maximum compensation threshold and the safety margin.

6. The method according to claim 1, characterized in that, If only the GNSS failure indication is sent and the actual drift rate of the terminal device is less than the maximum compensation threshold of the network device, then the TA adjustment strategy is the conventional compensation TA.

7. The method according to claim 1, characterized in that, If only the GNSS failure indication is sent and the actual drift rate of the terminal device is greater than the maximum compensation threshold of the network device, then the TA adjustment strategy is the enhanced compensation TA.

8. The method according to any one of claims 1-3 and 6, characterized in that, The conventional compensation TA is: the terminal device adjusts the TA based on the TAC sent by the network device.

9. The method according to any one of claims 3-4 and 6-7, characterized in that, The enhanced compensation TA includes at least one of the following compensation methods: The terminal device adjusts the TA based on the TAC sent by the network device, wherein the period during which the network device sends the TAC in the enhanced compensation TA is shorter than the period during which the network device sends the TAC in the regular compensation TA; The terminal device adjusts the TA according to the actual drift rate and the initial compensation value, wherein the initial compensation value is determined by the terminal device based on the last GNSS position; The terminal device adjusts the TA according to its actual location, wherein the actual location is determined by the terminal device using neighboring satellites.

10. The method according to any one of claims 1-4 and 6-7, characterized in that, Also includes: Monitor the speed changes of the terminal device; If the speed change causes a change in the first state information, then a second state information is sent to the network device.

11. The method according to any one of claims 1-4 and 6-7, characterized in that, The first TA adjustment indication is carried in the Radio Resource Control (RRC) signaling.

12. A communication method, characterized in that, Network devices used in non-terrestrial networks include: Receive a Global Navigation Satellite System (GNSS) failure indication and / or the first status information of the terminal device sent by a terminal device connected to the network device, wherein the first status information is determined based on the real-time moving speed of the terminal device, and the first status information is used to indicate the timing advance (TA) drift risk of the terminal device in the event of GNSS failure; A TA adjustment strategy is determined based on the GNSS failure indication and / or the first state information of the terminal device, wherein the TA adjustment strategy is a conventional compensation TA or an enhanced compensation TA; Send the first TA adjustment instruction corresponding to the TA adjustment strategy to the terminal device; If only the GNSS failure indication is received, then determining the TA adjustment strategy based on the GNSS failure indication and / or the first state information of the terminal device includes: The actual drift rate of the terminal device is determined by continuously measuring the detection reference signal (SRS) sent by the terminal device. The actual drift rate is compared with the maximum compensation threshold of the network device, and the TA adjustment strategy is determined based on the comparison result. The maximum compensation threshold is the maximum drift rate that the network device can compensate by periodically in advance by commanding TAC.

13. The method according to claim 12, characterized in that, The step of determining the TA adjustment strategy based on the GNSS failure indication and / or the first state information of the terminal device includes: If the first status information is received and the first status information indicates that the predicted drift rate of the terminal device is less than the maximum compensation threshold of the network device, then the TA adjustment strategy is determined to be the conventional compensation TA.

14. The method according to claim 12, characterized in that, The strategy for determining the timing advance (TA) adjustment based on the GNSS failure indication and / or the first state information of the terminal device includes: If the first status information is received and the first status information indicates that the predicted drift rate of the terminal device is greater than the maximum compensation threshold of the network device and less than the enhancement compensation threshold of the network device, then the actual drift rate corresponding to the terminal device is determined by continuously measuring the SRS sent by the terminal device. If the actual drift rate is less than the maximum compensation threshold, the TA adjustment strategy is determined to be the conventional compensation TA; otherwise, the TA adjustment strategy is determined to be the enhanced compensation TA.

15. The method according to claim 14, characterized in that, After sending the first TA adjustment instruction corresponding to the TA adjustment strategy to the terminal device, the method further includes: The actual drift rate is determined periodically by continuously measuring the SRS. If the actual drift rate changes from being less than the maximum compensation threshold to being greater than the maximum compensation threshold, a second TA adjustment instruction is sent to the terminal device. The second TA adjustment instruction is used to indicate that the TA adjustment strategy is the enhanced compensation TA.

16. The method according to claim 12, characterized in that, The strategy for determining the timing advance (TA) adjustment based on the GNSS failure indication and / or the first state information of the terminal device includes: If the first status information is received and the first status information indicates that the predicted drift rate of the terminal device is greater than the enhancement compensation threshold of the network device, then the TA adjustment strategy is determined to be the enhancement compensation TA.

17. The method according to claim 14 or 15, characterized in that, The enhanced compensation threshold is equal to the product of the maximum compensation threshold and the safety margin.

18. The method according to claim 12, characterized in that, If only the GNSS failure indication is received, then comparing the actual drift rate with the maximum compensation threshold of the network device and determining the TA adjustment strategy based on the comparison result includes: If the actual drift rate is less than the maximum compensation threshold of the network device, then the TA adjustment strategy is determined to be the conventional compensation TA; otherwise, the TA adjustment strategy is determined to be the enhanced compensation TA.

19. The method according to any one of claims 12-15, characterized in that, The conventional compensation TA is: the terminal device adjusts the TA based on the TAC sent by the network device.

20. The method according to any one of claims 14, 15, and 18, characterized in that, The enhanced compensation TA includes at least one of the following compensation methods: The terminal device adjusts the TA based on the TAC sent by the network device, wherein the period during which the network device sends the TAC in the enhanced compensation TA is shorter than the period during which the network device sends the TAC in the regular compensation TA; The terminal device adjusts the TA according to the actual drift rate and the initial compensation value, wherein the initial compensation value is determined by the terminal device based on the last GNSS position; The terminal device adjusts the TA according to its actual location, wherein the actual location is determined by the terminal device using neighboring satellites.

21. The method according to any one of claims 12-16, 18, characterized in that, The first TA adjustment indication is carried in the Radio Resource Control (RRC) signaling.

22. A communication device, characterized in that, The device includes at least one processor coupled to a memory storing a program or instructions, the processor executing the program or instructions to cause the device to perform the method as described in any one of claims 1 to 21.

23. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 21.

24. A communication system, characterized in that, Includes the communication device as described in claim 22.

25. A chip system comprising one or more processors, the one or more processors being configured to retrieve and execute instructions stored in memory, such that the method of any one of claims 1 to 21 is performed.

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