Communication method and communication device

Abstract

The invention discloses a communication method and a communication device, relates to the field of communication, and is used for pre-compensating Doppler frequency shift of an uplink signal and calculating uplink TA under the condition of not depending on positioning of terminal equipment. The method is applied to a terminal device, and the method comprises the following steps: receiving first configuration information, the first configuration information comprising position information of M reference points and a theoretical Doppler frequency shift value; sending an uplink signal according to the uplink time advance TA and the uplink frequency offset pre-compensation amount; the uplink frequency offset pre-compensation amount is obtained based on at least one of an actually-measured Doppler frequency shift value and a theoretical Doppler frequency shift value of the target reference point, and the actually-measured Doppler frequency shift value is obtained by measuring a first signal of the network equipment by the terminal equipment; the target reference point is obtained based on the actually measured Doppler frequency shift value and the theoretical Doppler frequency shift values of the M reference points, and the uplink TA is obtained based on the position information of the target reference point and the motion parameters of the network equipment.

Description

TECHNICAL FIELD

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

[0002] In a non-terrestrial network (NTN), a satellite moves rapidly relative to a terminal device on the ground, so that there is a large Doppler frequency shift between the wireless link between the satellite and the terminal device on the ground. In order to avoid interference between subcarriers and between multiple users in the uplink, the terminal device needs to pre-compensate the Doppler frequency shift of the uplink signal. In an NTN network, the round-trip time (RTT) between the terminal device and the network device is large, and it is difficult to solve the interference problem between different users by relying only on the cyclic prefix of the random access preamble, so it is necessary to estimate the uplink timing advance (TA) and introduce an open-loop TA component obtained based on location calculation.

[0003] Currently, in a 3rd generation partnership project (3GPP) NTN system, a terminal device pre-compensates a transmission frequency and calculates an uplink TA based on global navigation satellite system (GNSS) positioning. However, in some scenarios, the terminal device does not have GNSS positioning capability (does not have a GNSS module), or the terminal device cannot receive a GNSS signal (for example, entering a tunnel causes the GNSS signal to be blocked), or the GNSS positioning accuracy of the terminal device is poor, which will cause the terminal device to be unable to pre-compensate the Doppler frequency shift of the uplink signal and calculate the uplink TA, and unable to eliminate interference between subcarriers and between multiple users, thereby affecting the communication quality. Therefore, how to reduce communication interference in this case is a problem that needs to be solved. SUMMARY

[0004] Embodiments of the present application provide a communication method and a communication device for pre-compensating the Doppler frequency shift of the uplink signal and calculating the uplink TA without relying on terminal device positioning.

[0005] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions: In a first aspect, a communication method is provided, which is applied to a terminal device and includes: receiving, by the terminal device, first configuration information, the first configuration information including position information of M reference points and theoretical Doppler shift values, M being an integer greater than 1; measuring, by the terminal device, a first signal of the network device to obtain a measured Doppler shift value; obtaining, by the terminal device, a target reference point according to the measured Doppler shift value and the theoretical Doppler shift values of the M reference points; obtaining, by the terminal device, an uplink frequency offset pre-compensation amount according to at least one of the measured Doppler shift value and the theoretical Doppler shift value of the target reference point; obtaining, by the terminal device, an uplink TA according to the position information of the target reference point and a motion parameter of the network device; and then transmitting, by the terminal device, an uplink signal according to the uplink TA and the uplink frequency offset pre-compensation amount.

[0006] The motion parameter of the network device includes a motion parameter of a satellite or a motion parameter of an aerial platform. The motion parameter of the satellite can be an ephemeris of the satellite, which accurately describes position information, speed information, a motion direction, etc. of the satellite at a specific time point. The motion parameter of the aerial platform includes position information, speed information, a motion direction, etc. of the aerial platform at a specific time point. The core role of the motion parameter is to replace or supplement the motion parameter of the satellite, and it is suitable for non-satellite aerial platforms.

[0007] The communication method provided by the embodiments of the present application is that the network device transmits the position information and the theoretical Doppler shift values of each reference point in the coverage range of the beam. When the terminal device is close to a certain reference point, the Doppler shift value measured by the terminal device is close to the theoretical Doppler shift value of the reference point, so the terminal device can use the position information of the reference point to approximately replace the position information of the terminal device, and then combine the motion parameter of the network device to pre-compensate the Doppler shift of the uplink signal and calculate the uplink TA. Thus, without relying on the positioning of the terminal device, the Doppler shift of the uplink signal is pre-compensated and the uplink TA is calculated.

[0008] The core effect of the scheme is to provide a new solution path for NTN uplink synchronization without relying on the positioning of the terminal device, which fundamentally solves the industry problem of uplink TA and frequency synchronization when GNSS is unavailable, blocked or insufficient in accuracy. The scheme enables the terminal device to maintain accurate synchronization with a high-speed moving satellite or aerial platform without positioning capability, reduces the interference between subcarriers and between multiple users, and greatly improves the reliability of the NTN system.

[0009] It should be noted that the scheme provided by the embodiments of the present application can pre-compensate the frequency offset (Doppler shift) caused by the Doppler effect, and can also pre-compensate the frequency offset caused by other factors, such as the frequency offset caused by the clock crystal deviation, which is not limited by the present application.

[0010] It should be noted that the embodiments of this application are illustrated using GNSS positioning as an example, without loss of generality. The solutions provided in the embodiments of this application are also applicable to scenarios where the NTN system fails to calculate uplink TA and perform uplink frequency pre-compensation based on positioning using other technologies.

[0011] In one possible implementation, transmitting an uplink signal based on the uplink TA and the uplink frequency offset pre-compensation amount includes: transmitting an uplink signal based on at least one of the TA and the uplink frequency offset pre-compensation amount when a first condition is met, wherein the first condition includes at least one of the following: the terminal device does not have a positioning function module installed, the terminal device cannot receive a positioning signal, the positioning function of the terminal device is unavailable, the positioning accuracy of the terminal device is less than or equal to an accuracy threshold, the positioning error of the terminal device is greater than or equal to an error threshold, and the time interval since the most recent acquisition of the location information of the terminal device is greater than or equal to a time threshold.

[0012] Among them, at least one of the accuracy threshold, error threshold, or time threshold is configured by the network device or agreed upon by the protocol.

[0013] It should be noted that in this application, the positioning accuracy and positioning error of the terminal device can be statistically defined as positioning accuracy and positioning error. For example, a probability greater than or equal to A% indicates a positioning accuracy less than or equal to B; a probability greater than or equal to C% indicates a positioning error greater than or equal to D. Here, 0≤A≤1, 0≤C≤1, and the units of B and D can be distance units, such as meters (m) or centimeters (cm). For ease of explanation, and without causing misunderstanding, this application will simply refer to the positioning accuracy and positioning error under the above specific probability conditions as positioning accuracy and positioning error. That is, a probability greater than or equal to A% with a positioning accuracy less than or equal to B is simply described as positioning accuracy less than or equal to B; a probability greater than or equal to C% with a positioning error greater than or equal to D is simply described as positioning error greater than or equal to D. The values ​​of the above probability values ​​A and B are configured by the network or agreed upon through a protocol.

[0014] This implementation clarifies that the proposed solution can be triggered under conditions of limited terminal device positioning (unavailable, insufficient accuracy, or excessively long signal reception period), demonstrating its "on-demand activation" characteristic. It avoids unnecessary computational overhead when the terminal device's positioning is normal, achieving seamless collaboration and intelligent switching between traditional GNSS positioning schemes and the proposed solution. This design ensures optimal system performance in most cases (prioritizing the use of high-precision GNSS) while automatically activating a backup mechanism in case of GNSS anomalies, enhancing the overall robustness and energy efficiency of the system.

[0015] In one possible implementation, the method further includes: receiving first indication information, the first indication information being used for at least one of the following: activating P reference points out of the M reference points, deactivating Q reference points out of the M reference points, and finally maintaining the activated reference points and the M reference points using the same distribution model; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0016] This implementation further introduces first indication information, enabling dynamic and refined management of the reference point set by the network. By separating "semi-static configuration" from "dynamic activation," network devices can quickly adjust the actual available subset of reference points for terminal devices based on real-time scenarios (such as satellite beam switching, terminal movement, and changes in service load) without retransmitting the complete first configuration information. This not only significantly reduces signaling overhead but also significantly improves system response speed and resource allocation flexibility, enabling the network to adapt more agilely to the highly dynamic environmental characteristics of NTN.

[0017] In one possible implementation, the first indication information indicates a reference point among the M reference points in any of the following ways: the first indication information includes an index of an activated or deactivated reference point, the index of which is used to indicate the position of the reference point's location information among the M reference points' location information, or to indicate the position of the reference point's theoretical Doppler frequency shift value among the M reference points' theoretical Doppler frequency shift values; or, when the first configuration information further includes identifiers of the M reference points, the first indication information includes identifiers of activated or deactivated reference points; or, the first indication information indicates activated and deactivated reference points through a first bitmap, where one bit of the first bitmap corresponds to one reference point, one bit having a first value indicates that the corresponding reference point is activated, and one bit having a second value indicates that the corresponding reference point is deactivated.

[0018] This implementation discloses the three indication methods (identifier, index, and bitmap) for the first indication information, providing a flexible, efficient, and standards-friendly signaling implementation scheme. These methods are suitable for reference point sets of different sizes and signaling overhead constraints: the identification method is intuitive and clear, the index method is concise and efficient, and the bitmap method is suitable for compactly representing multiple activation points. This design allows the scheme to seamlessly adapt to existing protocol stacks, ensuring ease of deployment and good compatibility with protocol standards, while providing network devices with diverse control granularity options.

[0019] In one possible implementation, the first indication information is carried via a medium access control element (MAC CE) or downlink control information (DCI). The second indication information is carried via DCI.

[0020] This implementation sets the bearer of the first indication information to MAC CE or DCI. Setting it to DCI ensures the practical feasibility and protocol compatibility of the solution. MAC CE and DCI are mature and efficient control signaling carriers in existing 5G / NR systems, characterized by low latency and high reliability. By utilizing existing signaling channels, this solution does not require defining new physical channels or significantly modifying the protocol stack, reducing the difficulty of standardization and industrialization, and facilitating rapid deployment and widespread commercial use.

[0021] In one possible implementation, the target reference point is the reference point with the smallest deviation between the theoretical Doppler frequency shift value and the measured Doppler frequency shift value among the P activated reference points.

[0022] This implementation provides a target reference point selection strategy: when the terminal device is close to a certain reference point, the Doppler frequency shift value measured by the terminal device is close to the theoretical Doppler frequency shift value of that reference point. Therefore, the terminal device can use the location information of the reference point to approximate its own location information. Compared to using a single reference point, this significantly reduces the differential delay and residual frequency offset introduced by location deviation, thereby significantly improving the accuracy of uplink pre-compensation and ultimately effectively solving the problem of initial access failure caused by huge propagation delays.

[0023] In one possible implementation, the method further includes: after establishing a connection with the network device, sending first reporting information, the first reporting information being used to indicate a target reference point.

[0024] This implementation introduces a mechanism for terminal devices to report the location information of selected target reference points to network devices, establishing a closed loop of "terminal device feedback - network device optimization" for the first time in NTN uplink synchronization. This feedback enables network devices to: perceive the reference points actually used by terminal devices in real time; dynamically optimize the distribution of reference points based on big data of group behavior (e.g., increase density in hotspot areas and decrease density in blind spots); and diagnose configuration anomalies or terminal anomalies. This endows the network with self-learning and self-optimization capabilities, moving from static configuration to dynamic intelligent management.

[0025] In one possible implementation, the first reporting information is carried in any of the following ways: radio resource control (RRC) signaling, MAC CE, or uplink control information (UCI).

[0026] This implementation discloses that the first reported information can be carried via RRC, MAC CE, or UCI, providing a flexible reporting approach adaptable to different scenarios and terminal device states. RRC is suitable for infrequent detailed reporting, MAC CE is suitable for rapid dynamic reporting, and UCI is suitable for low-latency, small-data-volume reporting. This multi-path design ensures that the reporting mechanism can operate efficiently and reliably under different RRC states (idle state, connected state) and different service requirements (latency sensitive, bandwidth sensitive).

[0027] In one possible implementation, the first reporting information is used to update at least one of the following: first configuration information, first instruction information.

[0028] This implementation explicitly states that the location information of the target reference point reported by the terminal device is directly used for network updates of at least one of the following: first configuration information and first indication information, forming a complete "configuration-selection-reporting-optimization" closed loop. This enables network devices to iteratively optimize the distribution and activation strategies of reference points based on the actual experience and distribution of terminal devices, thereby continuously improving the synchronization accuracy and resource efficiency of the entire network and achieving self-evolution of network performance.

[0029] In one possible implementation, sending the first reporting information includes: sending the first reporting information according to the instruction of the network device, or sending the first reporting information when a second condition is met, or periodically sending the first reporting information; wherein the second condition includes at least one of the following: first configuration information update, first indication information update, second indication information update, change of target reference point, deterioration of GNSS status of terminal device, change of RRC status of terminal device, movement distance of terminal device exceeding range, and terminal device entering or exiting energy-saving mode.

[0030] This implementation method, by constructing a flexible, multi-dimensional, and adaptive reporting triggering system, enables network devices to achieve refined, real-time perception and closed-loop management of terminal device reference point selection behavior. This mechanism integrates three modes: network-initiated requests, terminal event-driven mechanisms, and periodic reporting, comprehensively covering key scenarios such as configuration updates, state switching, location changes, and energy-saving mode conversions. This allows network devices to promptly obtain information on the actual reference point usage and state transitions of terminal devices in a dynamic NTN environment. This not only provides direct and reliable feedback data for network-optimized reference point configuration but also significantly improves the system's response speed and adaptability to changes in terminal mobility, GNSS availability, and energy-saving strategies. Ultimately, it forms an efficient closed loop of "network configuration - terminal selection - information reporting - configuration optimization," enhancing the overall robustness, management intelligence, and resource utilization efficiency of NTN in complex and ever-changing scenarios.

[0031] In one possible implementation, the target reference point is the reference point among M reference points that has the smallest deviation between the theoretical and measured Doppler frequency shift values. This implementation provides a target reference point selection strategy—when the terminal device is close to a certain reference point, the Doppler frequency shift value measured by the terminal device is close to the theoretical Doppler frequency shift value of that reference point. Therefore, the terminal device can use the location information of the reference point to approximate its own location information. Compared to using a single reference point, this significantly reduces the differential delay and residual frequency offset introduced by location deviation, thereby significantly improving the accuracy of uplink pre-compensation and ultimately effectively solving the problem of initial access failure caused by huge propagation delays.

[0032] In one possible implementation, M reference points are distributed along the diameter of the network device's direction of motion within the network device's beam coverage area.

[0033] The magnitude of the Doppler shift depends on the radial relative velocity between the network device and the terminal device. Within the beam coverage area, the radial velocity components of each reference point differ most significantly along the direction of movement of the network device. If the reference points are randomly distributed or distributed perpendicular to the direction of movement of the network device, some reference points may have similar Doppler shift values, making it difficult for the terminal device to distinguish the reference points after measurement. Furthermore, this method ensures that each reference point has a significantly different theoretical Doppler shift value. These Doppler shift values ​​form a monotonically varying sequence from the front edge of the beam (maximum positive value) to the beam center (close to zero) and then to the rear edge of the beam (maximum negative value). This improves matching accuracy: when the terminal device compares the measured Doppler shift value with this significantly different sequence of theoretical Doppler shift values, the uniqueness and robustness of the matching result are greatly enhanced, significantly reducing the probability of incorrect reference point selection due to measurement noise or errors. This is equivalent to improved positioning resolution: using the same number of reference points, the highest geographical resolution is achieved.

[0034] In one possible implementation, the first configuration information also includes a timestamp indicating the time at which the theoretical Doppler frequency shift values ​​for the M reference points are generated.

[0035] Because the Doppler frequency shift caused by the movement of network devices is time-sensitive, the terminal device can determine whether the theoretical Doppler frequency shift value is valid based on the timestamp, that is, whether it can be used to determine the location information of the reference point.

[0036] In one possible implementation, the first configuration information is carried via a system information block (SIB) or RRC signaling.

[0037] This implementation sets the first configuration information to be carried by either SIB or RRC signaling, ensuring high reliability and wide coverage of the first configuration information distribution. SIB broadcasting enables all terminal devices within the coverage area (including non-camped cell terminal devices) to obtain the first configuration information; RRC signaling allows the network to provide personalized configurations for specific terminal devices. These two methods complement each other, balancing the universality and specialization of system information dissemination, which is the fundamental guarantee for the large-scale deployment of this solution.

[0038] Secondly, a communication method is provided, applied to a network device. The method includes: the network device sending first configuration information, which includes position information of M reference points and theoretical Doppler frequency shift values, where M is an integer greater than 1. The network device receives an uplink signal based on the uplink TA and an uplink frequency offset pre-compensation amount. The uplink frequency offset pre-compensation amount is obtained based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The measured Doppler frequency shift value is obtained by a terminal device measuring the first signal of the network device. The target reference point is obtained based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of the M reference points. The uplink TA is obtained based on the position information of the target reference point and the motion parameters of the network device.

[0039] In one possible implementation, the method further includes: sending first indication information, the first indication information being used for at least one of the following: activating P reference points out of M reference points, deactivating Q reference points out of M reference points, and finally maintaining the activated reference points and the M reference points using the same distribution model; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0040] In one possible implementation, the first indication information indicates a reference point among the M reference points in any of the following ways: The first indication information includes the index of the activated or deactivated reference point. The index of the reference point is used to indicate the position of the reference point's location information among the M reference points, or to indicate the position of the theoretical Doppler frequency shift value of the reference point among the theoretical Doppler frequency shift values ​​of the M reference points. Alternatively, when the first configuration information also includes the identifiers of the M reference points, the first indication information includes the identifiers of the activated or deactivated reference points. Alternatively, the first indication information indicates the activated and deactivated reference points through a first bit map, where one bit of the first bit map corresponds to one reference point, one bit with a first value indicates that the corresponding reference point is activated, and one bit with a second value indicates that the corresponding reference point is deactivated.

[0041] In one possible implementation, the first instruction information is carried via MAC CE or DCI.

[0042] In one possible implementation, the target reference point is the reference point with the smallest deviation between the theoretical Doppler frequency shift value and the measured Doppler frequency shift value among the P activated reference points.

[0043] In one possible implementation, the method further includes: after establishing a connection with the terminal device, receiving first reporting information, the first reporting information being used by the terminal device to indicate a target reference point.

[0044] In one possible implementation, the first reporting information is carried in any of the following ways: RRC signaling, MACCE, or UCI.

[0045] In one possible implementation, the first reporting information is used to update at least one of the following: first configuration information, first instruction information, and second instruction information.

[0046] In one possible implementation, the target reference point is the reference point with the smallest deviation between the theoretical Doppler frequency shift value and the measured Doppler frequency shift value among M reference points.

[0047] In one possible implementation, M reference points are distributed along the diameter of the network device's direction of motion within the network device's beam coverage area.

[0048] In one possible implementation, the first configuration information also includes a timestamp indicating the time at which the theoretical Doppler frequency shift values ​​for the M reference points are generated.

[0049] In one possible implementation, the first configuration information is carried via SIB or RRC signaling.

[0050] Thirdly, a communication device is provided, comprising a processing module and a communication module. The communication module receives first configuration information, including position information of M reference points and theoretical Doppler frequency shift values, where M is an integer greater than 1. The processing module measures a first signal from a network device to obtain a measured Doppler frequency shift value. The processing module determines a target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of the M reference points. The processing module obtains an uplink frequency offset pre-compensation amount based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The processing module obtains an uplink TA based on the position information of the target reference point and the motion parameters of the network device. The communication module transmits an uplink signal based on the uplink TA and the uplink frequency offset pre-compensation amount.

[0051] In one possible implementation, the communication module is used to send an uplink signal according to TA and uplink frequency offset pre-compensation amount when a first condition is met, wherein the first condition includes at least one of the following: the terminal device does not have a positioning function module installed, the terminal device cannot receive a positioning signal, the positioning function of the terminal device is unavailable, the positioning accuracy of the terminal device is less than or equal to an accuracy threshold, the positioning error of the terminal device is greater than or equal to an error threshold, and the time interval since the most recent acquisition of the location information of the terminal device is greater than or equal to a time threshold.

[0052] In one possible implementation, the communication module is used to receive first indication information, which is used for at least one of the following: activating P reference points out of M reference points, deactivating Q reference points out of M reference points, and finally keeping the activated reference points and the M reference points using the same distribution model; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0053] In one possible implementation, the communication module is used to send a first reporting message after establishing a connection with the network device, the first reporting message being used to indicate a target reference point.

[0054] In one possible implementation, the communication module is used to send a first reporting information according to the instructions of the network device, or, when a second condition is met, send the first reporting information, or periodically send the first reporting information; wherein the second condition includes at least one of the following: first configuration information update, first indication information update, second indication information update, target reference point change, GNSS status of terminal device deterioration, RRC status of terminal device change, moving distance of terminal device exceeding range, terminal device entering or exiting energy-saving mode.

[0055] Fourthly, a communication device is provided, comprising a processing module and a communication module. The communication module is used to transmit first configuration information, which includes position information of M reference points and theoretical Doppler frequency shift values, where M is an integer greater than 1. The communication module is used to receive an uplink signal based on the uplink TA and an uplink frequency offset pre-compensation amount; the uplink frequency offset pre-compensation amount is obtained based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The measured Doppler frequency shift value is obtained by the terminal device measuring the first signal of the network device. The target reference point is obtained based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of the M reference points. The uplink TA is obtained based on the position information of the target reference point and the motion parameters of the network device.

[0056] In one possible implementation, the communication module is used to send first indication information, which is used for at least one of the following: activating P reference points out of M reference points, deactivating Q reference points out of M reference points, and finally keeping the activated reference points and the M reference points using the same distribution model; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0057] In one possible implementation, the communication module is used to receive first reporting information after establishing a connection with the terminal device. The first reporting information is used by the terminal device to indicate a target reference point.

[0058] Fifthly, a communication device is provided, including a processor. The processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the method in any possible implementation of the first aspect described above. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0059] In one implementation, the communication interface may be a transceiver, or an input / output interface.

[0060] In another implementation, the communication device is a chip configured in a network device. When the communication device is a chip configured in a network device, the communication interface can be an input / output interface.

[0061] In a sixth aspect, a communication device is provided, including a processor. The processor is coupled to a memory and can be used to execute instructions or data in the memory to implement the method in any possible implementation of the second aspect described above. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0062] In one implementation, the communication interface may 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] In a seventh aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the method in any possible implementation of the first or second aspect described above.

[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] Eighthly, a communication device is provided, including a processor and a memory. The processor is configured to read instructions stored in the memory, receive signals via a receiver, and transmit signals via a transmitter to execute the method in any possible implementation of the first or second aspect described above.

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

[0068] Ninthly, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions), which, when the computer program is run, causes a computer to perform the method in any possible implementation of the first or second aspect described above.

[0069] In a tenth aspect, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform the methods in any possible implementation of the first or second aspect described above.

[0070] Eleventhly, embodiments of this application provide a chip system including one or more processors for calling and executing instructions stored in memory, causing the methods in any possible implementation of the first or second aspect to be executed. 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 twelfth aspect, a communication system is provided, including the aforementioned communication devices, such as terminal equipment and network equipment. Optionally, the communication system may further include other devices that communicate with the terminal equipment and network equipment.

[0073] The technical effects of the second to twelfth aspects refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. Attached Figure Description

[0074] Figure 1 This application provides a schematic diagram of the architecture of a communication system. Figure 2 A schematic diagram of a TA provided in an embodiment of this application; Figure 3 A flowchart illustrating a communication method provided in an embodiment of this application; Figure 4 A schematic diagram showing the location of a reference point within the beam coverage area of ​​a network device provided in an embodiment of this application; Figure 5 A flowchart illustrating another communication method provided in an embodiment of this application; Figure 6 A flowchart illustrating another communication method provided in an embodiment of this application; Figure 7 A flowchart illustrating another communication method provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application; Figure 9 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0075] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0076] First, some concepts involved in this application will be described.

[0077] The terms "first" and "second" used in the embodiments of this application are only used to distinguish features of the same type and should not be construed as indicating relative importance, quantity, order, etc.

[0078] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0079] The technical solutions provided in this application can be applied to various communication systems, such as: 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, non-terrestrial network (NTN) communication systems, 5th generation (5G) mobile communication systems, new radio access technology (NR), future communication systems, and 5G Advanced communication systems. Among these, 5G mobile communication systems can include non-standalone (NSA) or standalone (SA) networks. The technical solutions provided in this application can also be applied to future communication systems. This application does not limit this application. The terms "system" and "network" in the embodiments of this application are often used interchangeably, and the described technologies can be used not only for the systems and radio technologies mentioned above, but also for other systems and radio technologies.

[0080] Figure 1 This is a schematic diagram of the architecture of a communication system provided in an embodiment of this application. The communication system 100 can be a communication system combining NTN and terrestrial networks. The communication system 100 may include network device 110 and terminal device 120. The network device 110 and the terminal device 120 can communicate with each other via a wireless link.

[0081] Figure 1 An exemplary embodiment is shown, comprising a network device 110 and multiple terminal devices 120. Optionally, the communication system 100 may further include multiple network devices 110 and multiple terminal devices 120.

[0082] The network equipment in this application can be a satellite used for satellite communication, such as Tiantong satellite communication and Xingwang satellite communication, or it can be an aircraft (such as a drone, helicopter, airplane, or hot air balloon). Network equipment can also be network-side equipment such as access network equipment and core network equipment. Network equipment can include access network equipment, mobility management entity (MME), home subscriber server (HSS), access management function (AMF) network elements, and session management function (SMF) network elements.

[0083] The MME is used for signaling processing, such as attach, detach, and tracking area updates. It is also used for user authentication, session management, and mobility management (e.g., handover control). The HSS stores core user data, such as the International Mobile Subscriber Identity (IMSI) and authentication keys. It also manages user subscription information, such as Quality of Service (QoS) policies.

[0084] AMF network elements are used for user access and mobility management, including functions such as handling terminal device access requests, mobility management, and radio resource allocation.

[0085] SMF network elements are used for session management functions, such as tunnel maintenance, IP address allocation and management, UP function selection, policy enforcement and quality of service (QoS) control, billing data collection, roaming, etc.

[0086] Access network equipment, sometimes also called access nodes, has wireless transceiver capabilities for communicating with terminals. Access network equipment includes, but is not limited to, base stations, evolved NodeBs (eNodeBs), transmission reception points (TRPs) in the aforementioned communication systems, next-generation NodeBs (gNBs) in 5G mobile communication systems, access network equipment or modules in open RAN (ORAN) systems, satellites in NTN communication systems, base stations in future mobile communication systems, or access nodes in WiFi systems. Access network equipment can also be modules or units capable of implementing some of the functions of a base station. Access network equipment can be macro base stations, micro base stations, indoor stations, relay nodes, donor nodes, or wireless controllers in cloud radio access network (CRAN) scenarios. Optionally, access network equipment can also be servers, wearable devices, or vehicle-mounted equipment. For example, in vehicle-to-everything (V2X) technology, the access network equipment can be a roadside unit (RSU). Multiple access network devices in a communication system can be base stations of the same type or different types. Base stations can communicate with terminals directly or via relay stations. Terminals can communicate with multiple base stations using different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the access network devices.

[0087] In this application, the means for implementing the functions of a network device can be a network device itself, or a means capable of supporting the network device in implementing those functions, such as a processor, circuit, chip, or chip system. This means can be installed in or connected to the network device. In the technical solutions provided in this application, the example of a network device being used to implement the functions of a network device is used to describe the technical solutions provided in this application.

[0088] The terminal device in this application can be a terminal device capable of wireless communication. The terminal device can be a device that provides voice and 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 satellite communication, 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, 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.

[0089] 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 the terminal device or connected to and used with 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.

[0090] 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).

[0091] 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.

[0092] To facilitate understanding of the embodiments of this application, the terminology used in this application is first briefly explained. Optionally, the explanation of some terms can also refer to the explanations in the 3rd Generation Partnership Project (3GPP) standard protocol. It should be understood that the technical terms in this application are only examples and not limitations. 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.

[0093] Timing advance (TA): In mobile communication, due to the distance between terminal devices and network devices, signal transmission delays occur, causing uplink signals from different terminal devices to arrive at the network device at different times, potentially leading to interference. To solve this problem, signals sent by different terminal devices on the same subframe are required to arrive at the network device at essentially the same time. The network device can use TA to receive signals from terminal devices within the cyclic prefix (CP) range.

[0094] Timing advance of terminal devices is an important parameter for adjusting the uplink transmission time of terminal devices, which refers to the amount of time advance between the uplink frame sent by the terminal device and the corresponding downlink frame. Figure 2 A schematic diagram of a TA provided in an embodiment of this application is shown below. Figure 2 As shown, the i-th uplink frame is TA ahead of the i-th downlink frame.

[0095] In existing communication protocols, the calculation method for timing advance is as follows: .in, For the timing advance of network indication, different Different lead times apply. This is the timing advance offset, used for timing calibration to ensure the consistency of the timing advance calculation. The timing advance between the uplink synchronization reference point in the feeder link and the satellite is indicated by the network. The timing advance for the service link (i.e., the link between the terminal equipment and the satellite), also known as the open-loop timing advance. As a time unit, ,in, .

[0096] It should be noted that, and These three parameters are sent from the network to the terminal device, and they can be collectively referred to as closed-loop TA. This parameter is calculated by the terminal device based on its own location and can also be called open-loop TA.

[0097] In this context, network devices can instruct terminal devices via timing advance commands (TACs) from the Media Access Control Element (MAC CE). Network devices can indicate to terminal devices via random access response (RAR). Network devices can broadcast to terminal devices via system information blocks (SIBs). For example, via SIB 19 broadcast.

[0098] For example, during random access, the terminal device reports a preamble to the network device via the physical random access channel (PRACH). The network device calculates the initial timing advance based on the received preamble and sends the calculated initial timing advance to the terminal device via the TAC in the random access response (RAR). This TAC is an index value corresponding to a specific time adjustment amount. Additionally, the RAR also includes... After the terminal device detects the RAR, it calculates the corresponding time adjustment amount based on the TAC in the RAR. Then according to and Adjust the timing for sending uplink frames.

[0099] In connected mode, network devices can send MAC CE TAC messages to terminal devices in real time. It broadcasts in real time to terminal devices via SIB 19. The terminal device calculates its location based on its own position. and upon receiving and Afterwards, according to and Calculate Then according to Adjust the uplink frame transmission time. Currently, terminal devices obtain their own location based on GNSS and calculate based on the obtained location. .

[0100] Non-terrestrial networks (NTNs) refer to network architectures that utilize network equipment such as satellites and aerial platforms as relays to provide communication services to terminal devices. Traditional terrestrial network (TN) cellular communication systems (such as 4G / 5G) cannot provide seamless coverage, especially in areas where base stations cannot be deployed, such as oceans, deserts, and the air. NTNs can extend the coverage of traditional terrestrial networks, achieving seamless global connectivity. The characteristics of NTN communication are: large communication range; for areas currently inaccessible or prohibitively expensive to cover by cellular communication systems, such as oceans, deserts, and remote mountainous areas, communication can be established between any two points within the coverage area of ​​the radio waves emitted by network equipment (such as satellites). They are less susceptible to land-based disasters and have high reliability. In extreme situations such as earthquakes where cellular communication infrastructure becomes unavailable, NTN communication can quickly establish communication connections. For latency-sensitive services requiring long-distance transmission, NTN communication can reduce transmission latency.

[0101] Airborne platforms refer to high-altitude or mid-altitude communication platforms in NTN (Network Telecommunications) other than satellites. These mainly include the following categories: High-altitude platforms: These are quasi-stationary platforms that remain stationary in the stratosphere (approximately 20-50 kilometers above sea level) for extended periods, such as solar-powered drones, balloons, or airships. They move extremely slowly relative to the ground and can be considered "quasi-stationary." Airborne base stations: These are aircraft carrying communication equipment (e.g., commercial airliners, dedicated communication drones) that serve as mobile base stations, providing services to ground users or users inside the aircraft. They move relatively quickly, but their trajectories are relatively predictable (flying along a flight path). Low-altitude drone base stations: These are drones that hover or move slowly at low altitudes (e.g., several hundred meters) to provide temporary or emergency cellular coverage. They offer flexible mobility but have a small service range.

[0102] Satellite motion parameters, such as satellite ephemeris, are a set of data files containing satellite orbital parameters and time information. It precisely describes the satellite's position, velocity, and direction of motion at a specific point in time. Satellite ephemeris includes: orbital shape (whether the satellite's orbit is a perfect circle or an ellipse, the radius of a circle, and the major and minor axes of an ellipse); the satellite's direction of motion and velocity; and its spatiotemporal position (the satellite's position on its orbit at a precise moment).

[0103] Terminal devices can determine the satellite's position, velocity, and direction of motion at a specific point in time based on the satellite's ephemeris information. Based on this information and its own position, the terminal device can determine the Doppler shift value and trend of the wireless link, and perform frequency pre-compensation (or frequency adjustment) on the uplink frequency before signal transmission to reduce frequency changes caused by the Doppler shift.

[0104] The motion parameters of an airborne platform include its position, speed, and direction of motion at a specific point in time. Its core function is to replace or supplement the motion parameters of satellites, and it is applicable to non-satellite airborne platforms. Terminal equipment can determine the Doppler shift value and its trend based on the above information and its own position information, and perform frequency pre-compensation (or frequency adjustment) on the uplink frequency before signal transmission to reduce frequency changes caused by Doppler shift.

[0105] Doppler shift refers to the carrier frequency shift caused by the relative radial motion between the transmitter and receiver.

[0106] For network equipment that is satellite, especially medium Earth orbit (MEO) and low Earth orbit (LEO) satellites, the rapid movement relative to ground-based terminal equipment results in significant Doppler shift in the wireless link between the satellite and ground equipment. To avoid interference between uplink subcarriers and among multiple users, terminal equipment needs to pre-compensate for the Doppler shift of the uplink signal and calculate the uplink timing advance (TA). This involves adjusting the transmission frequency and time of the uplink signal to ensure that the uplink signals transmitted by each terminal device arrive at the network equipment at the specified frequency and time, thereby eliminating interference between subcarriers and among multiple users.

[0107] Currently, terminal devices rely on Global Navigation Satellite System (GNSS) positioning to pre-compensate transmission frequencies and calculate uplink TA. However, in certain scenarios, GNSS becomes ineffective. For example, the terminal device may lack positioning capabilities (not equipped with a GNSS module), or it may be unable to receive GNSS signals (GNSS signals are blocked), or its positioning accuracy may be poor. These issues will prevent the terminal device from pre-compensating for the Doppler shift of the uplink signal and calculating the uplink TA, thus failing to eliminate interference between subcarriers and between multiple users, impacting communication quality.

[0108] like Figure 1 As shown, even if the location information of a common reference point (e.g., the beam center) within the beam coverage area of ​​the network device is used to replace the location information of all terminal devices within the beam coverage area, and the Doppler frequency shift of the uplink signal is pre-compensated and the uplink TA is calculated, due to the wide beam coverage area, there may be a huge deviation between the actual location of each terminal device and the location of the common reference point. This results in the pre-compensation based on the location information of the common reference point being seriously inconsistent with the actual pre-compensation required by the terminal devices.

[0109] In view of this, this application provides a communication method. Since the circular coverage area of ​​the downlink beam of a network device (e.g., a satellite or an airborne platform) can include M reference points, each corresponding to a location information and a theoretical Doppler frequency shift value, when a terminal device is close to one of the reference points, the Doppler frequency shift value measured by the terminal device is close to the theoretical Doppler frequency shift value of that reference point. Therefore, the terminal device can use the location information of the reference point to approximate its own location information. Combined with the motion parameters of the network device, the Doppler frequency shift of the uplink signal is pre-compensated, and the uplink TA is calculated. Thus, without relying on the terminal device's positioning, the Doppler frequency shift of the uplink signal can be pre-compensated, and the uplink TA can be calculated.

[0110] The core effect of this solution lies in providing a completely new approach to NTN uplink synchronization that does not rely on terminal device positioning. By enabling terminal devices to calculate uplink TA and uplink frequency offset pre-compensation based on the location information of reference points configured in the network (rather than their own location information), it fundamentally solves the industry-wide problem of uplink time and frequency asynchrony when GNSS is unavailable, blocked, or lacks sufficient accuracy. This solution allows terminal devices to maintain precise synchronization with high-speed moving satellites or aerial platforms even without positioning capabilities, greatly improving the reliability, coverage continuity, and terminal compatibility of the NTN system. It is a key technology for a fully covered integrated air-space network.

[0111] It should be noted that the solution provided in this application can pre-compensate for frequency shift (Doppler frequency shift) caused by the Doppler effect, and can also pre-compensate for frequency shift caused by other factors, such as frequency shift caused by clock crystal oscillator deviation. This application does not limit this.

[0112] It should be noted that the embodiments of this application are illustrated using GNSS positioning as an example, without loss of generality. The solutions provided in the embodiments of this application are also applicable to scenarios where the NTN system fails to calculate uplink TA and perform uplink frequency pre-compensation based on positioning using other technologies.

[0113] 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 in the illustrative flowcharts (e.g., terminal devices, network devices) 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.

[0114] As a general statement, the message or signaling interactions involved in the interaction process of this application embodiment can be standard messages or signaling or newly introduced messages or signaling. This application embodiment does not make specific limitations on this.

[0115] Figure 3 This is a flowchart illustrating a communication method provided in an embodiment of this application. Figure 3 The terminal device in the middle can be Figure 1 The term "terminal device" can also refer to the components within a terminal device (such as a processor, chip, or chip system). Figure 3 The network devices in the middle can be Figure 1 The term "network device" can also refer to the components within a network device (such as processors, chips, or chip systems). For example... Figure 3 As shown, the communication method 300 includes the following steps S301-S302.

[0116] S301. The network device sends first configuration information to the terminal device. The first configuration information includes the location information of M reference points and the theoretical Doppler frequency shift value, where M is an integer greater than 1.

[0117] The network device can periodically send first configuration information, such as periodically broadcasting it, to prevent reference points from becoming invalid due to outdated information. The network device can also send the first configuration information to some terminal devices within its beam coverage area. Correspondingly, the terminal devices receive the first configuration information from the network device. M reference points are distributed within the beam coverage area of ​​the network device. The difference in theoretical Doppler frequency shift values ​​between different reference points is greater than a frequency shift threshold to ensure that each reference point is physically distinguishable in the frequency domain.

[0118] For example, the M reference points can be distributed along the diameter of the beam coverage area along the direction of movement of the network device (i.e., the direction of the velocity vector projected onto the ground). The reason is as follows: The magnitude of the Doppler shift depends on the radial relative velocity between the network device and the terminal device. Within the beam coverage area, the radial velocity components of each reference point differ most significantly along the direction of movement of the network device. If the reference points are randomly distributed or distributed perpendicular to the direction of movement of the network device, some reference points may have similar Doppler shift values, making it difficult for the terminal device to distinguish the reference points after measurement. Furthermore, this method ensures that each reference point has a significantly different theoretical Doppler shift value. These Doppler shift values ​​form a monotonically varying sequence from the front edge of the beam (maximum positive value) to the beam center (close to zero) and then to the rear edge of the beam (maximum negative value). This improves matching accuracy: when the terminal device compares the measured Doppler shift value with this significantly different sequence of theoretical Doppler shift values, the uniqueness and robustness of the matching result are greatly enhanced, significantly reducing the probability of incorrect reference point selection due to measurement noise or errors. This is equivalent to improved positioning resolution: using the same number of reference points, the highest geographical resolution is achieved.

[0119] This simplifies computation and signaling overhead. The two-dimensional beam coverage problem is reduced to a one-dimensional problem along a line (diameter). Dimensionality reduction modeling significantly simplifies the complexity of network devices calculating the theoretical Doppler shift value of the reference point. Since the reference point lies on a line, its location information can be efficiently represented using one-dimensional coordinates (distance or coordinate offset relative to the beam center) instead of complete two-dimensional (longitude, latitude) or three-dimensional coordinates, thus reducing signaling overhead.

[0120] It should be noted that the number M can be dynamically adjusted. Network devices can also plan the distribution model of reference points in other ways, such as distributing the M reference points along diameters in other directions, distributing the M reference points evenly in a grid pattern, or distributing the M reference points as concentric circles with different diameters centered on the beam center, etc. This application does not impose limitations on these methods. The M reference points can be distributed at equal intervals or unequal intervals; some reference points can be distributed at equal intervals, while the remaining reference points can be distributed at unequal intervals. For example, reference points closer to the beam center can be denser, while reference points closer to the beam edge can be sparser. The reasons are as follows: Near the beam center, the Doppler frequency shift caused by the relative motion of network equipment varies drastically with spatial location, exhibiting extremely high frequency domain sensitivity. Due to the significant differences in theoretical Doppler frequency shift values ​​between different reference points, the system possesses extremely strong feature discrimination capabilities. Therefore, reference points near the beam center can be more densely packed, fully utilizing this high sensitivity characteristic to achieve extremely high-resolution position matching and more accurate tone compensation.

[0121] At the beam edge, the Doppler frequency shift tends to level off with displacement, and the frequency domain characteristics are less sensitive to positional changes. If reference points are set too densely in this region, the theoretical frequency shift difference between adjacent points may be smaller than the inherent measurement error of the terminal equipment, causing the terminal equipment to fail to effectively distinguish the target reference point and resulting in matching failure. Therefore, if reference points are set too densely, the theoretical Doppler frequency shift difference between adjacent reference points may be smaller than the measurement error range of the terminal equipment, causing the terminal to be unable to accurately distinguish the target reference point (i.e., mismatch occurs). To ensure the resolvability of reference points, the physical distance between reference points should be appropriately increased in the beam edge region to ensure a sufficiently large theoretical frequency shift difference between adjacent reference points for the terminal to perform feature matching.

[0122] For example, Figure 4 This is a schematic diagram illustrating the location of reference points within the beam coverage area of ​​a network device according to an embodiment of this application. Within the circular beam coverage area of ​​the network device 110, a diameter is defined along the direction of movement of the network device 110. This diameter is divided into an even number (2N) equal-length segments, where the number N is determined by the desired positioning accuracy of the network device; the larger N is, the higher the positioning accuracy. This results in 2N+1 segmented points (including the beam center), which serve as reference points. In this case, 2N+1 = M.

[0123] Each reference point corresponds to a location information and a theoretical Doppler frequency shift value. When the terminal device 120 is close to a certain reference point (e.g., reference point 401), the Doppler frequency shift value measured by the terminal device is close to the theoretical Doppler frequency shift value of the reference point. In this case, the terminal device 120 can use the location information of the reference point to approximate the location information of the terminal device 120.

[0124] The location information and theoretical Doppler frequency shift value corresponding to the same reference point can be transmitted together. For example, {location information of reference point 0, theoretical Doppler frequency shift value of reference point 0}, {location information of reference point 1, theoretical Doppler frequency shift value of reference point 1}, {location information of reference point 2, theoretical Doppler frequency shift value of reference point 2}, and so on.

[0125] The location information and theoretical Doppler frequency shift value corresponding to the same reference point can also be transmitted separately, using the same index to correspond to the same reference point. The index of the reference point is used to indicate the position of the location information of the reference point among the location information of M reference points, or to indicate the position of the theoretical Doppler frequency shift value of the reference point among the theoretical Doppler frequency shift values ​​of M reference points. The value range of the reference point index is [0, M-1] or [1, M].

[0126] For example, the first configuration information includes {location information of reference point 0, location information of reference point 1, location information of reference point 2}, and {theoretical Doppler frequency shift value of reference point 0, theoretical Doppler frequency shift value of reference point 1, and theoretical Doppler frequency shift value of reference point 2}. Then, the index corresponding to reference point 0 is 0, the index corresponding to reference point 1 is 1, and the index corresponding to reference point 2 is 2.

[0127] The location information of each reference point can include its latitude and longitude coordinates [latitude, longitude], and optionally, its altitude information. Taking the location information including the latitude and longitude coordinates of the reference point as an example, the location information of the M reference points included in the first configuration information can be represented as {[latitude0, longitude0], [latitude1, longitude1], [latitude2, longitude2]}, etc.

[0128] Alternatively, the location information of the reference point at the beam center can include the latitude and longitude coordinates [latitude, longitude] of the reference point, while the location information of other reference points can include coordinate offset values ​​relative to the beam center. For example, the location information of the M reference points included in the first configuration information can be represented as {[latitude0, longitude0], [latitude_offset1, longitude_offset1], [latitude_offset2, longitude_offset2]}, etc. Since the offset values ​​are on a smaller order of magnitude than the coordinate values, signaling overhead can be reduced. It should be noted that coordinate offset values ​​relative to other reference points (such as reference points near the beam edge close to the forward direction of the network device) can also be used, and this application does not limit this.

[0129] Alternatively, the location information of the reference point at the beam center can include the latitude and longitude coordinates [latitude, longitude] of the reference point, while the location information of other reference points can include their distances relative to the beam center. For example, the location information of the M reference points included in the first configuration information can be represented as {[latitude0, longitude0], offset1, offset2}, etc. Since the motion parameters of the network device include the direction of motion of the network device, the terminal device can calculate the location of each reference point based on this information. Because the distance is on a smaller order of magnitude than the coordinate value, signaling overhead can be reduced. It should be noted that coordinate offset values ​​relative to other reference points (such as reference points near the edge of the beam close to the direction of travel of the network device) can also be used, and this application does not limit this.

[0130] Taking M=2N+1 as an example, the theoretical Doppler frequency shift values ​​of 2N+1 reference points can be represented as a list, set, array, etc. For example, the theoretical Doppler frequency shift values ​​of 2N+1 reference points can be represented as an array D[-N]~D[N], where D[0] refers to the theoretical Doppler frequency shift value of the reference point at the beam center, and this value is 0, so it can be ignored. The theoretical Doppler frequency shift value D[n] of reference point n is obtained through formulas 1 and 2, where -N≤n≤N, and n is an integer.

[0131] Formula 1.

[0132] Formula 2.

[0133] in, For carrier frequency, For the speed of network devices, At the speed of light, Angle of elevation For the height of network equipment, The diameter of the beam range. The sign of the Doppler shift value indicates the direction of relative motion between the network device and the reference point; a positive value indicates that the network device is approaching the reference point, and a negative value indicates that the network device is moving away from the reference point.

[0134] Optionally, the first configuration information may also include a timestamp, which indicates the time when the theoretical Doppler frequency shift values ​​for the M reference points were generated. Since the Doppler frequency shift caused by the movement of network devices is time-sensitive, the terminal device can determine whether the theoretical Doppler frequency shift values ​​are valid, i.e., whether they can be used to determine the location information of the reference points, based on the timestamp.

[0135] Optionally, the first configuration information may also include the identifiers (IDs) of M reference points, and the first configuration information may also be represented as {ID0: [latitude0, longitude0], ID1: [latitude1, longitude1], ID2: [latitude2, longitude2]}, etc.

[0136] Location information, theoretical Doppler frequency shift value, and identifier corresponding to the same reference point can be transmitted together. For example, {location information of reference point 0, theoretical Doppler frequency shift value of reference point 0, identifier of reference point 0}, {location information of reference point 1, theoretical Doppler frequency shift value of reference point 1, identifier of reference point 1}, {location information of reference point 2, theoretical Doppler frequency shift value of reference point 2, identifier of reference point 2}, and so on.

[0137] Location information, theoretical Doppler frequency shift values, and identifiers corresponding to the same reference point can also be sent separately, using the same index to correspond to the same reference point. For example, {location information of reference point 0, location information of reference point 1, location information of reference point 2}, {theoretical Doppler frequency shift value of reference point 0, theoretical Doppler frequency shift value of reference point 1, theoretical Doppler frequency shift value of reference point 2}, {identifier of reference point 0, identifier of reference point 1, identifier of reference point 2}, and so on.

[0138] For example, the first configuration information can be carried in the system information block (SIB) or radio resource control (RRC) signaling of the physical downlink shared channel (PDSCH). For instance, a network device periodically broadcasts SIB19, enabling all terminal devices within its coverage area to receive the first configuration information. As another example, a network device sends RRC signaling to a terminal device within its coverage area, causing that terminal device to receive the first configuration information. It should be noted that information between the terminal device and the network device can be transmitted directly or forwarded through other devices.

[0139] This implementation sets the first configuration information to be carried by either SIB or RRC signaling, ensuring high reliability and wide coverage of the first configuration information distribution. SIB broadcasting enables all terminal devices within the coverage area (including non-camped cell terminal devices) to obtain the first configuration information; RRC signaling allows the network to provide personalized configurations for specific terminal devices. These two methods complement each other, balancing the universality and specialization of system information dissemination, which is the fundamental guarantee for the large-scale deployment of this solution.

[0140] Optionally, the network device may also send first indication information to the terminal device. Accordingly, the terminal device receives the first indication information from the network device. The first indication information is used for at least one of the following: activating P reference points out of M reference points, or deactivating Q reference points out of M reference points. P + Q = M, where P and Q are both integers greater than or equal to 0 and less than or equal to M. In other words, the first indication information is used to activate P pairs of position information and theoretical Doppler frequency shift values, or to deactivate Q pairs of position information and theoretical Doppler frequency shift values. The first configuration information is equivalent to configuring the entire set of reference points, and the first indication information is equivalent to activating or deactivating a subset or the entire set of reference points.

[0141] The final active reference points adopt the same distribution model as the M reference points. The final active reference points refer to: the P active reference points, or the P reference points remaining after removing the Q deactivated reference points from the M reference points. For example, if the M reference points are uniformly distributed, then the final active reference points will also be uniformly distributed. As another example, if the M reference points are denser near the beam center and sparser near the beam edges, then the final active reference points will also be denser near the beam center and sparser near the beam edges. This ensures consistency in the distribution model of the reference points before and after activation.

[0142] For example, the first indication information can be carried in the medium access control element (MAC CE) or downlink control information (DCI). MAC CE and DCI are mature and efficient control signaling carriers in existing 5G / NR systems, characterized by low latency and high reliability. By utilizing existing signaling channels, this solution does not require defining new physical channels or significantly modifying the protocol stack, ensuring the practical feasibility and protocol compatibility of the solution, reducing the difficulty of standardization and industrialization, and facilitating rapid deployment and widespread commercial use.

[0143] The first instruction information can indicate (either activate or deactivate) a reference point among M reference points in any of the following ways: In one possible implementation, the first indication information may include the index of the reference point to be activated or deactivated, where the index of the reference point ranges from [0, M-1] to [1, M]. The indexes of the reference points can form a list, set, array, etc. For example, if the first indication information is {0, 2}, it indicates that two reference points, namely reference points at index 0 and index 2, are activated or deactivated.

[0144] In another possible implementation, when the first configuration information further includes identifiers of M reference points, the first indication information may include identifiers of activated or deactivated reference points. For example, if the first indication information is {ID0, ID2}, it indicates that two of the reference points are activated or deactivated, namely reference points identified as ID0 and ID2, respectively.

[0145] In another possible implementation, the first indication information can indicate activated and deactivated reference points via a first bitmap. For example, the first bitmap includes M bits, where each bit corresponds to a reference point. A first value (e.g., 1) indicates activation of the corresponding reference point, and a second value (e.g., 0) indicates deactivation. A total of P bits are designated as first values, and a total of Q bits are designated as second values. For example, if the first bitmap is 8100...0, it indicates activation of two reference points, namely the first reference point and the third reference point.

[0146] It should be noted that, in this embodiment, the index of the reference point corresponds to the reference point sorting. When the reference point sorting changes, the reference point index also changes. The identifier of the reference point is unique and will not change with the reference point sorting.

[0147] The three indication methods (identifier, index, and bitmap) described above for the first indication information provide a flexible, efficient, and standards-friendly signaling implementation scheme. These methods are suitable for reference point sets of different sizes and signaling overhead constraints: the identification method is intuitive and clear, the index method is concise and efficient, and the bitmap method is suitable for compactly representing multiple activation points. This design allows the scheme to seamlessly adapt to existing protocol stacks, ensuring ease of deployment and good compatibility with protocol standards, while providing network devices with diverse control granularity options.

[0148] This application embodiment achieves dynamic and refined management of the reference point set by further introducing first indication information. By separating "semi-static configuration" from "dynamic activation," network devices can quickly adjust the actual available subset of reference points for terminal devices based on real-time scenarios (such as satellite beam switching, terminal movement, and changes in service load) without retransmitting the complete first configuration information. This not only significantly reduces signaling overhead but also significantly improves system response speed and resource allocation flexibility, enabling the network to adapt more agilely to the highly dynamic environmental characteristics of NTN. Specifically, it includes the following advantages: This approach enables low-frequency transmission of the entire set of reference points with high overhead, while high-frequency adjustment of activation commands with low overhead, resulting in lower overall overhead. It also reduces signaling overhead. The location information of the N candidate reference points indicated by the first configuration information can be a large and relatively static set, requiring no frequent updates. Network devices dynamically activate or deactivate reference points using lightweight first indication information, avoiding frequent transmission of location information and reducing signaling overhead.

[0149] Lightweight activation signaling enables rapid switching of activated location information, facilitating quick updates and responses. When network devices move, network topology changes, or terminal devices enter a new downlink beam coverage area, the network devices can quickly change the location information and theoretical Doppler shift values ​​required by the terminal devices by sending new initial indication information, without needing to resend the complete and potentially large amount of location information and theoretical Doppler shift values. This reduces update latency and enhances adaptability to dynamic NTN environments.

[0150] Adapting to terminal devices that move over large areas. For a terminal device moving over a large geographical area (such as a vehicle-mounted terminal device or an airborne terminal device), the network device can configure location information of a wide range of reference points covering the terminal device's movement path at once using initial configuration information. Subsequently, as the terminal device moves, the network device only needs to switch the activated subset of reference points via lightweight signaling to guide the terminal device to use the location information most suitable for its current location for calculations.

[0151] Network management flexibility. Network devices can configure the same reference point for all terminal devices within a cell or area, and then activate different reference points for terminal devices based on different accuracy requirements, different mobility modes, or different areas, using different initial indication information. This enables differentiated and granular network management.

[0152] S302. The terminal device sends an uplink signal to the network device based on the uplink TA and the uplink frequency offset pre-compensation amount. The uplink frequency offset pre-compensation amount is obtained based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The measured Doppler frequency shift value is obtained by the terminal device measuring the first signal of the network device. The target reference point is obtained based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of M reference points. The uplink TA is obtained based on the position information of the target reference point and the motion parameters of the network device.

[0153] Accordingly, the network device receives the uplink signal based on the uplink TA and the uplink frequency offset pre-compensation amount. For example, a terminal device initiates random access to the network device. The frequency at which the terminal device sends the uplink signal (i.e., the transmission frequency of the uplink signal) is equal to the reference frequency plus the uplink frequency offset pre-compensation amount. It should be noted that the uplink frequency offset pre-compensation amount can be positive, negative, or zero. Figure 2 As shown, the transmission time of the i-th uplink frame containing the uplink signal is earlier than the transmission time of the i-th downlink frame, and this time difference is TA. This is to compensate for the propagation delay and achieve uplink synchronization.

[0154] The reference frequency can be the transmission frequency of a previous uplink signal at a specific time. In frequency division duplex (FDD) scenarios, the reference frequency can be indicated by the network device. In time division duplex (TDD) scenarios, the terminal device can determine the reference frequency based on the transmission or reception frequency of the downlink signal; that is, the reference frequency is equal to the transmission or reception frequency of the downlink signal. This method can be applied when the terminal device is in idle or connected mode.

[0155] The motion parameters of network devices include the motion parameters of satellites or airborne platforms, depending on whether the network device is a satellite or an airborne platform.

[0156] The following explains how the terminal device obtains the uplink TA and uplink frequency offset pre-compensation amount: Specifically, Figure 5 This is a flowchart illustrating another communication method provided in an embodiment of this application. S302 includes S3021-S3024: S3021. The terminal device measures the first signal of the network device and obtains the measured Doppler frequency shift value.

[0157] The first signal may include a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), a demodulation reference signal (DM-RS), etc.

[0158] Taking the first signal as SSB as an example, the terminal device first performs initial time-frequency synchronization of the SSB signal.

[0159] The terminal device receives the center frequency as SSB signal Perform frequency domain shifting and mixing to a center frequency of The baseband, where n is the sampling time. Center frequency The corresponding global synchronization channel number (GSCN) is used. Then, a low-pass filter (LPF) is applied to suppress out-of-band noise, yielding the baseband signal. This process is illustrated in Equation 3. Formula 3.

[0160] in, For baseband signals, LPF is a low-pass filter. Sampling rate, for arrive Frequency offset.

[0161] Subsequently, the terminal device detects the primary synchronization signal (PSS) of the SSB. This is because the terminal device locally stores all possible PSS sequences. (in For community signage, (For subcarrier configuration) The time-domain signal of the SSB contains a PSS sequence, which the terminal device transmits via the baseband signal. A sliding cross-correlation operation is performed with each local PSS sequence to search for the best match. This process is illustrated in Equation 4: Formula 4.

[0162] in, This marks the starting position for PSS timing synchronization. Finally, the terminal device determines the parameter combination that maximizes the correlation output by detecting the peak value of the cross-correlation result. This process is shown in Equation 5: Formula 5.

[0163] Through the above process, the terminal device not only obtains its own cell identifier and subcarrier spacing configuration, but also completes the initial time-frequency synchronization, laying a key foundation for the subsequent frequency offset calculation process.

[0164] Then, the terminal device can estimate the Doppler frequency shift value, which can include integer multiples of the Doppler frequency shift value. and fractional multiples of Doppler frequency shift value .

[0165] Taking the first signal as SSB as an example, for integer multiples of the Doppler frequency shift value, since the PSS sequence of SSB has good autocorrelation characteristics in the frequency domain, the Doppler frequency shift value of PSS can be estimated by performing correlation operations in the frequency domain.

[0166] Specifically, the terminal equipment receives baseband signals. Perform a discrete Fourier transform (DFT) to obtain the frequency domain PSS sequence. The terminal device uses the pre-determined cell identifier. and subcarrier configuration Generate frequency domain PSS sequences locally The corresponding time-domain PSS sequence is Then, the terminal device processes the received frequency-domain PSS sequence in the frequency domain. and locally generated frequency domain PSS sequence By performing cross-correlation calculations, integer multiples of the Doppler frequency shift can be obtained. This process is shown in Formula 6: Formula 6.

[0167] The peak position of this cross-correlation result corresponds to an integer multiple of the Doppler frequency shift value. ,Right now .

[0168] For fractional Doppler frequency shift values, the baseband signal model affected by fractional Doppler frequency shift values ​​is shown in Equation 7: Formula 7.

[0169] in, To obtain the initial position after initial time-frequency synchronization, N is the length of the PSS sequence. The terminal device will then transmit the baseband signal... With local PSS signal Conjugate multiplication of time-domain sequences. This process is shown in Equation 8: Formula 8.

[0170] As can be seen from Formula 8, due to the presence of fractional octave frequency offset, the sequence... The first half of the sequence and the second half of the sequence will produce a Doppler shift value that is a fraction of a factor. A proportional phase difference. Through the sequence By performing correlation operations between the first half and the second half of the sequence, the fractional octet frequency offset can be accurately estimated. This process is illustrated in Formula 9: Formula 9.

[0171] According to Formula 9, the fractional Doppler frequency shift value can be calculated. ∠R is the argument of the complex number R, measured in radians. Terminal equipment uses integer multiples of the Doppler frequency shift value. and fractional multiples of Doppler frequency shift value The measured Doppler frequency shift value was obtained. The process is shown in Formula 10: Formula 10.

[0172] in, This represents the subcarrier spacing.

[0173] S3022. The terminal device obtains the target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of M reference points.

[0174] When the first configuration information includes a timestamp, if the time difference between the current time and the timestamp is less than a time threshold, it indicates that the theoretical Doppler frequency shift value is still valid. The terminal device can then obtain the target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of M reference points. If the time difference between the current time and the timestamp is greater than or equal to the time threshold, it indicates that the theoretical Doppler frequency shift value is invalid. The terminal device cannot obtain the target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of M reference points and must wait for the network device to update the first configuration information.

[0175] If the terminal device does not receive the first instruction information, it calculates the deviation between the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of each of the M reference points, and selects the reference point with the smallest deviation as the target reference point. In other words, the target reference point is the reference point among the M reference points with the smallest deviation between the theoretical and measured Doppler frequency shift values.

[0176] If the terminal device receives the first instruction information, it calculates the deviation between the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of each of the P activated reference points, and selects the reference point with the smallest deviation as the target reference point. In other words, the target reference point is the reference point with the smallest deviation between the theoretical and measured Doppler frequency shift values ​​among the P activated reference points.

[0177] The process is shown in Formula 11: Formula 11.

[0178] Where j represents the index of the target reference point, D[i] represents the theoretical Doppler frequency shift value of reference point i, -N≤i≤N, and i is an integer.

[0179] This method is based on the principle of consistent uplink and downlink Doppler frequency shifts under the same conditions. It introduces "Doppler frequency shift matching" as a reference point selection criterion, creatively utilizing downlink channel characteristics to infer the location of the terminal device. Based on the principle of consistent downlink Doppler frequency shifts, this method selects the closest reference point by matching the measured downlink Doppler frequency shift value with the theoretical Doppler frequency shift of each reference point. Its advantages are: it is completely independent of GNSS positioning; it fully utilizes existing downlink signals, is simple to implement, and the terminal can complete the process autonomously and quickly; it has adaptive capabilities to time-varying channels, making it particularly suitable for mobile scenarios. It has the following advantages: Enhance system robustness and coverage reliability. In extreme cases where GNSS signals are blocked (such as indoors, tunnels, urban canyons) or the terminal lacks a GNSS module, the system can still maintain NTN uplink synchronization, avoiding communication interruption and truly achieving ubiquitous coverage.

[0180] Achieving a balance between energy saving and performance. Allowing terminal devices to extend GNSS signal reception cycles or even temporarily disable GNSS to save power. During gaps in terminal device positioning, the system can seamlessly take over, maintaining uplink synchronization, thus achieving energy savings without compromising performance.

[0181] This reduces terminal complexity and cost. It provides a feasible path for low-complexity, low-cost terminals (such as large-scale IoT sensors) to access NTN networks. These terminals can complete the necessary synchronization using only a communication receiver without a GNSS module, significantly reducing hardware costs and power consumption.

[0182] Terminal devices can quickly and adaptively select the location information of the target reference point. The closest frequency shift selection mechanism has low computational load and can be completed quickly and autonomously by the terminal device without multiple signaling interactions with network devices, reducing synchronization establishment latency, and can adaptively follow the movement of the terminal device or changes in the channel.

[0183] Improve the resource management efficiency of network equipment. Network equipment no longer needs to perform complex real-time location calculations or beam tracking for each non-GNSS terminal device. With just a set of location information configured, the terminal device can autonomously complete the calculations and compensation, reducing the computational and signaling burden on the network equipment.

[0184] S3023. The terminal equipment uses the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount, or uses the measured Doppler frequency shift value as the uplink frequency offset pre-compensation amount, or uses the linear mean of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount.

[0185] For terminal devices using the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount, intelligent matching is performed using the terminal device's measured values, but uplink compensation is performed using clean theoretical values ​​sent by the network device. This achieves precise alignment between the network device and the terminal device in the compensation model, completely isolating the terminal device's measurement noise and individual biases. This ensures that all terminal devices selecting the same reference point have consistent and predictable uplink frequency offsets, thereby greatly simplifying the design of the network device's receiver and significantly improving the determinism and overall reliability of the system's initial access in GNSS failure scenarios. This is achieved at the cost of minimal, controlled residual errors, in exchange for maximum improvement in system-level performance.

[0186] Using the measured Doppler frequency shift value as the uplink frequency offset pre-compensation amount for terminal devices provides optimal instantaneous dynamic tracking capability and enables rapid response to link changes.

[0187] For terminal equipment, using the linear mean of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value at the target reference point as the uplink frequency offset pre-compensation amount means: Uplink frequency offset pre-compensation amount = a Measured Doppler frequency shift value +b The theoretical Doppler frequency shift value of the target reference point is given by a+b=1, where a and b are weights. This method balances instantaneous tracking and long-term stability, smoothing measurement noise to some extent and partially correcting minor deviations between the theoretical and measured Doppler frequency shift values. Furthermore, by adjusting the values ​​of a and b, the weights of the measured and theoretical Doppler frequency shift values ​​of the target reference point can be adjusted, making the uplink frequency offset pre-compensation amount more biased towards either the measured or theoretical Doppler frequency shift value of the target reference point.

[0188] S3024. The terminal device obtains the uplink TA based on the location information of the target reference point and the motion parameters of the network device.

[0189] Terminal devices can dynamically adjust components based on the closed-loop configuration of network devices. Fixed offset Public adjustment components Round-trip propagation delay between the target reference point and network devices Basic Time Units Calculate the upstream TA. The process is shown in Formula 12: Formula 12.

[0190] in, , , The method for determining this can be found in the provisions of 3GPP protocols TS 38.211 and TS 38.213. It should be noted that, in the embodiments of this application, Formula 2... It is calculated based on the location information of the target reference point and the motion parameters of the network device. For example, This equals the round-trip propagation delay between the target reference point and the network device, i.e., 2. (Distance between the target reference point and the network device) / speed of light. The distance between the target reference point and the network device is obtained from the position information of the target reference point and the position information of the network device. The position information of the network device comes from the motion parameters of the network device.

[0191] Optionally, if the first condition is met, the terminal device executes S302. This causes the terminal device to perform pre-compensation for the Doppler frequency shift of the uplink signal and calculate the uplink TA based on the location information of the reference point, achieving pre-compensation for the Doppler frequency shift of the uplink signal and calculation of the uplink TA without relying on the terminal device's positioning. If the first condition is not met, the terminal device does not need to execute S302. Instead, the terminal device performs pre-compensation for the Doppler frequency shift of the uplink signal and calculates the uplink TA based on the GNSS positioning information to achieve high-precision pre-compensation. The first condition essentially describes the case where GNSS is invalid; not meeting the first condition essentially describes the case where GNSS is valid.

[0192] The first condition includes at least one of the following: the terminal device does not have a positioning function (e.g., GNSS) module installed; the terminal device cannot receive positioning signals (e.g., entering a tunnel causes GNSS signals to be blocked); the positioning function of the terminal device is unavailable (e.g., the user disables the GNSS positioning function); the positioning accuracy of the terminal device is less than or equal to the accuracy threshold (e.g., 50m); the positioning error of the terminal device is greater than or equal to the error threshold (e.g., 45m); and the time interval since the most recent acquisition of the terminal device's location information is greater than or equal to the time threshold (e.g., 10 seconds).

[0193] It should be noted that the various thresholds involved in the embodiments of this application can be configured by network devices, agreed upon through protocols, or set independently by terminal devices.

[0194] This implementation method clarifies that the solution can be triggered even when GNSS is invalid, reflecting its "on-demand activation" characteristic. It avoids unnecessary computational overhead when the terminal device's positioning is normal, achieving seamless collaboration and intelligent switching between traditional GNSS positioning schemes and the solution proposed in this application. This design ensures optimal system performance in most cases (prioritizing the use of high-precision GNSS) while automatically activating a backup mechanism when GNSS is abnormal, enhancing the overall robustness and energy efficiency of the system.

[0195] Furthermore, this method can compensate for the loss of location information when the terminal device's positioning is unavailable, has low accuracy, or has been in use for an extended period. This prevents the pre-compensation of Doppler shift in the uplink signal and the calculation of uplink TA, thus avoiding uplink synchronization disorder or loss of lock and improving link stability. It also eliminates interference between subcarriers and between multiple users, ensuring communication quality. Additionally, it allows the terminal device to extend the GNSS signal reception period to save power. This implementation method maintains uplink synchronization between two adjacent terminal device positioning operations, achieving energy savings without performance degradation.

[0196] Optionally, the terminal device may also send first reporting information to the network device after establishing a connection with the network device. Correspondingly, the network device receives the first reporting information after establishing a connection with the terminal device. The first reporting information is used to indicate the target reference point, and can then be used by the network device to update at least one of the following: first configuration information, first indication information.

[0197] For example, the first reported information can be carried in any of the following ways: signaling, MAC CE, or uplink control information (UCI). This provides a flexible reporting approach that adapts to different scenarios and terminal device states. RRC is suitable for infrequent detailed reporting, MAC CE is suitable for rapid dynamic reporting, and UCI is suitable for low-latency, small-data-volume reporting. This multi-path design ensures that the reporting mechanism can work efficiently and reliably under different RRC states (idle state, connected state) and different service requirements (latency sensitive, bandwidth sensitive).

[0198] The terminal device may send a first reporting message according to the instructions of the network device (via DCI), or, under the condition of meeting a second condition, the terminal device may send a first reporting message to the network device, or the terminal device may periodically send a first reporting message to the network device. The second condition includes at least one of the following: first configuration information update, first instruction information update, change of target reference point, deterioration of GNSS status of the terminal device, change of RRC status of the terminal device, movement distance of the terminal device exceeding range, or the terminal device entering or exiting energy-saving mode.

[0199] When the first configuration information or the first indication information changes, the terminal device sends the first reporting information, enabling the network device to obtain the updated target reference point in a timely manner and achieve better data transmission.

[0200] A change in the target reference point refers to a change in the target reference point selected by the terminal device. This can reflect changes in the terminal device's location in real time.

[0201] GNSS status deterioration can include: a change from being able to receive GNSS signals to being unable to receive GNSS signals; a change in the GNSS positioning accuracy of the terminal device from less than a first accuracy threshold (e.g., 5m) to greater than a second accuracy threshold (e.g., 45m); and a change in the GNSS positioning error of the terminal device from less than a first error threshold (e.g., 10m) to greater than a second error threshold (e.g., 50m). Applicable scenarios include the terminal device entering a tunnel or indoors; GNSS module failure; and the user disabling the GNSS positioning function.

[0202] A change in RRC state refers to the transition of a terminal device's RRC state between the IDLE, INACTIVE, and CONNECTED states. For example, a terminal device sends its first reporting message after transitioning from the IDLE or INACTIVE state to the CONNECTED state. Another example is the terminal device sending its first reporting message for the last time before transitioning from the CONNECTED state to the IDLE or INACTIVE state. This is integrated with the connection management process to prevent the terminal device from reporting while in the IDLE or INACTIVE state.

[0203] "Movement distance exceeding range" refers to a situation where, since the last transmission of the first reported information, the distance moved exceeds a distance threshold (e.g., 500 meters), or the number of target reference point switching exceeds a frequency threshold (e.g., 3 times). When the first condition is not met, the movement distance can be measured; when the first condition is met, the number of target reference point switching can be counted. This ensures that the first reported information is not sent too frequently, while still reflecting significant changes in the terminal device's location.

[0204] Entering or exiting energy-saving mode refers to the following: After entering energy-saving mode, the terminal device extends the GNSS signal reception period or even shuts down GNSS. During the interval between two adjacent GNSS signal measurements, or during the period when GNSS is off, it relies on the aforementioned target reference point for positioning, and then calculates the uplink TA and uplink frequency offset pre-compensation. The terminal device sends a first reporting message, enabling the network device to clearly know when the terminal device started relying on the target reference point, and can adjust the monitoring and management strategy for the terminal device, such as reducing the frequency of TA adjustments. After exiting energy-saving mode, the terminal device resumes GNSS measurement or GNSS reception. The terminal device sends a first reporting message, enabling the network device to perform problem diagnosis, retrospectively analyze whether the target reference point used during the energy-saving period was reasonable, and whether the synchronization deviation was caused by inaccurate selection of the target reference point.

[0205] This implementation method, by constructing a flexible, multi-dimensional, and adaptive reporting triggering system, enables network devices to achieve refined, real-time perception and closed-loop management of terminal device reference point selection behavior. This mechanism integrates three modes: network-initiated requests, terminal event-driven mechanisms, and periodic reporting, comprehensively covering key scenarios such as configuration updates, state switching, location changes, and energy-saving mode conversions. This allows network devices to promptly obtain information on the actual target reference point usage and GNSS status changes of terminal devices in a dynamic NTN environment. This not only provides direct and reliable feedback data for network devices to optimize reference point configuration but also significantly improves the system's response speed and adaptability to changes in terminal mobility, GNSS availability, and energy-saving strategies. Ultimately, it forms an efficient closed loop of "network configuration - terminal selection - information reporting - configuration optimization," enhancing the overall robustness, management intelligence, and resource utilization efficiency of NTN in complex and ever-changing scenarios.

[0206] For example, the first reported information may include the index of the target reference point among the M reference points. For instance, the first reported information may include an index of 2, indicating that the target reference point is the reference point corresponding to index 2 among the M reference points.

[0207] The first reported information can indicate the target reference point through a second bitmap. For example, the second bitmap includes M bits, and one bit of the second bitmap corresponds to one of the M reference points. A bit of the second bitmap with the eighth value (e.g., 0) indicates that the corresponding reference point is not the target reference point, and a bit of the third bitmap with the ninth value (e.g., 1) indicates that the corresponding reference point is the target reference point. For example, if the second bitmap is 00100...0, it means that the third reference point is the target reference point. When the first configuration information includes identifiers of M reference points, the first reported information can indicate the target reference point through the identifier of the target reference point. For example, if the first reported information is {ID2}, it means that the target reference point is the reference point corresponding to identifier ID2.

[0208] The network device can update at least one of the following based on the target reference points reported by at least one terminal device: first configuration information and first indication information. For example, in areas with dense terminal devices, the number of reference points configured in the first configuration information can be increased, or the number of reference points activated by the first indication information can be increased, or the number of reference points deactivated by the first indication information can be decreased. This is equivalent to setting a denser number of reference points to improve positioning accuracy, thereby improving the accuracy of pre-compensation for Doppler frequency shift of uplink signals and the calculation of uplink TA. As another example, in areas with sparse terminal devices, the number of reference points configured in the first configuration information can be decreased, or the number of reference points activated by the first indication information can be decreased, or the number of reference points deactivated by the first indication information can be increased. This is equivalent to setting a sparser number of reference points to save signaling overhead. For instance, the network device can adjust the number, distribution, density, etc., of reference points based on the first reported information.

[0209] It should be noted that for the remaining reference points after additions or reductions, the difference in theoretical Doppler frequency shift values ​​between different reference points must also be greater than the frequency shift threshold to ensure that each reference point is physically distinguishable in the frequency domain.

[0210] This implementation explicitly states that the target reference point reported by the terminal device is directly used by the network device to update at least one of the following: first configuration information and first instruction information, forming a complete "configuration-selection-reporting-optimization" closed loop. This enables the network device to iteratively optimize the distribution and activation strategy of reference points based on the actual experience and distribution of terminal devices, thereby continuously improving the synchronization accuracy and resource efficiency of the entire network and achieving self-evolution of network performance.

[0211] This implementation introduces a mechanism for terminal devices to report selected target reference points to network devices, establishing a closed loop of "terminal device feedback - network device optimization" for the first time in NTN uplink synchronization. This feedback enables network devices to: perceive the reference points actually used by terminal devices in real time; dynamically optimize the distribution of reference points based on big data of group behavior (e.g., increase density in hotspot areas and decrease density in blind spots); and diagnose configuration anomalies or terminal anomalies. This endows the network with self-learning and self-optimization capabilities, moving from static configuration to dynamic intelligent management.

[0212] Specifically, this implementation method has the following advantages: closed-loop feedback, supporting network devices to dynamically adjust the distribution of reference points. Without feedback, network devices can only configure reference points based on geographical prediction or uniform grids, which is inefficient. Reporting target reference points transforms reference point configuration from open-loop prediction to closed-loop learning, significantly improving resource allocation efficiency and reducing the blindness of network side-blind configuration.

[0213] Assist network devices in evaluating configuration validity and diagnosing network anomalies. For example, if the target reference points reported by most terminal devices are significantly different from the network expectations, it indicates that the configuration of the first configuration information and the first indication information may be incorrect. If the target reference point reported by a terminal device is obviously abnormal (e.g., far from its serving cell), it indicates that the terminal device is in an abnormal state (e.g., location failure, excessive movement speed).

[0214] For terminal devices, this can improve communication quality. By optimizing the distribution of reference points based on reported target reference points, network devices can obtain more accurate location information that better reflects their true location, thereby improving uplink synchronization accuracy and communication quality. Additionally, it can reduce the power consumption of terminal devices. A better reference point configuration allows terminal devices to converge faster and with less computation during calculations, reducing power increases or retransmissions caused by synchronization inaccuracies in subsequent communications.

[0215] Furthermore, due to the high-speed movement of network equipment such as satellites relative to terminal devices, the Doppler frequency shift may change, potentially rendering the initial indication information invalid and unusable for determining the target reference point. After a certain period, the terminal device needs to reacquire the initial indication information. Therefore, the initial indication information is valid within a first time period, meaning it can be used to determine the target reference point, thus ensuring the timeliness of the initial indication information.

[0216] In one possible implementation, the first time period refers to the time period from a first moment (start time) to a second moment (end time). The first moment corresponds to the time when the first event occurs, and the second moment corresponds to the time when the second event occurs. This is equivalent to triggering the terminal device to determine the target reference point through the event.

[0217] For example, the first event refers to the quality of the terminal device's positioning signal being less than or equal to the signal quality threshold A1, or the positioning accuracy of the terminal device being less than or equal to the positioning accuracy threshold B1; the second event refers to the quality of the terminal device's positioning signal being greater than or equal to the signal quality threshold A2, or the positioning accuracy of the terminal device being greater than or equal to the positioning accuracy threshold B2. The signal quality threshold A2 is greater than the signal quality threshold A1, and the positioning accuracy threshold B2 is greater than the positioning accuracy threshold B1. That is, when the positioning quality of the terminal device deteriorates or the positioning accuracy of the terminal device decreases, the terminal device can determine the target reference point based on the first indication information. Without relying on the terminal device's positioning, pre-compensation for the Doppler frequency shift of the uplink signal and calculation of the uplink TA are achieved. When the positioning quality of the terminal device improves or the positioning accuracy of the terminal device increases, the uplink signal frequency pre-compensation based on the terminal device's positioning is restored, and the uplink TA is calculated.

[0218] Optionally, the values ​​of signal quality threshold A1, signal quality threshold A2, positioning accuracy threshold B1, and positioning accuracy threshold B2 can be agreed upon by the protocol or configured by the network device. That is, the network device sends second configuration information to the terminal device, and the terminal device receives the second configuration information accordingly. The second configuration information includes at least one of the following: signal quality threshold A1, signal quality threshold A2, positioning accuracy threshold B1, and positioning accuracy threshold B2.

[0219] For example, the first event refers to the first time the first indication information is used to determine the target reference point; the second event refers to the Kth time the first indication information is used to determine the target reference point; where K is an integer greater than or equal to 1. In other words, because the satellite moves at high speed relative to the terminal equipment, the Doppler frequency shift may change, and the first indication information can be used to determine the target reference point a finite number of times (K times). After K times, the terminal equipment needs to reacquire the first indication information.

[0220] In another possible implementation, the first time period refers to the time period from a first moment (start moment) to a second moment (end moment). The first moment is the moment when the first indication information is received plus a first offset, or the first moment is the moment when the Hybrid Automatic Repeat Request (HARQ) acknowledgment (ACK) corresponding to the first indication information is sent plus a second offset. The second moment is the first moment plus a first duration, or the second moment is the moment when the next first indication information begins to take effect.

[0221] It should be noted that each offset (first offset, second offset) is used to allow time for the terminal device to determine the target reference point based on the first indication information, calculate the uplink TA and uplink frequency offset pre-compensation amount, and send uplink signals. The HARQ-ACK corresponding to the first indication information is used to indicate to the network device that the terminal device has received the first indication information.

[0222] The reception time of the first indication information and the transmission time of the HARQ ACK corresponding to the first indication information can be absolute time, such as Coordinated Universal Time (UTC), or relative time, such as the Ath system frame, the Bth half frame, the Cth subframe, the Dth time slot, the Eth orthogonal frequency division multiplexing (OFDM) symbol, etc.

[0223] The first offset, second offset, first duration, and second duration are all greater than or equal to 0, and can be absolute or relative time (e.g., A system frames, B half-frames, C subframes, D time slots, E OFDM symbols). They can be agreed upon by a protocol or configured by the network device. Specifically, the network device sends third configuration information to the terminal device, and the terminal device receives the third configuration information from the network device. The third configuration information includes at least one of the following: first offset indication information, used by the terminal device to determine the first offset; second offset indication information, used by the terminal device to determine the second offset; first duration indication information, used by the terminal device to determine the first duration; and second duration indication information, used by the terminal device to determine the second duration. These indications can indicate specific values ​​(e.g., 2ms, 4ms) or the corresponding indices (e.g., 2ms corresponds to index 0, 4ms corresponds to index 1), which is not limited in this embodiment.

[0224] For example, the first time period can be represented as .in, The moment when the terminal device receives the first indication information, or the moment when the terminal device sends the HARQ ACK corresponding to the first indication information. This is either the first offset or the second offset. This is the first duration.

[0225] For example, the first time period can be represented as .in, This is the moment when the next first instruction message takes effect. The time can be absolute, such as UTC, or relative, such as the time corresponding to the Ath system frame, the Bth half-frame, the Cth subframe, the Dth time slot, or the Eth OFDM symbol. The meanings of other parameters are described above and will not be repeated here.

[0226] Compared to the second example, the first example, due to its shorter timeframe for the first indication information to take effect, results in smaller errors in the calculated uplink TA and uplink frequency offset pre-compensation amounts. The second example, compared to the first, allows for a continuous first timeframe, meaning the first indication information is always in effect. The terminal device can consistently determine the target reference point based on the first indication information, thereby calculating the uplink TA and uplink frequency offset pre-compensation amounts.

[0227] In another possible implementation, the first time period is the running time of the first timer. The parameters of the first timer (start time, restart time, shutdown time, and running duration) can be agreed upon by the protocol or configured by the network device.

[0228] For example, if the second condition is met, the terminal device starts or restarts the first timer. The second condition is that the terminal device receives the first indication information. In other words, the first indication information becomes effective when the terminal device receives it.

[0229] For example, the network device sends fourth configuration information to the terminal device. Correspondingly, the terminal device receives the fourth configuration information from the network device. The fourth configuration information includes at least one of the following: start / stop information, used to start, restart, or stop the first timer; and duration information, used to indicate the runtime of the first timer. That is, the network device triggers the first indication information to take effect. The start / stop information can each occupy one bit; for example, a start / stop information value of 1 indicates starting or restarting the first timer, and a start / stop information value of 0 indicates stopping the first timer. The duration information can indicate a specific value (e.g., 2ms, 4ms), or it can indicate the index corresponding to the value (e.g., 2ms corresponds to index 0, 4ms corresponds to index 1). This application does not limit the time unit for the runtime. This application does not limit the time unit for the runtime.

[0230] The communication method provided in this application involves a network device transmitting the location information and theoretical Doppler frequency shift values ​​of various reference points within the beam coverage area. When a terminal device is close to a certain reference point, the Doppler frequency shift value measured by the terminal device is close to the theoretical Doppler frequency shift value of that reference point. Therefore, the terminal device can use the location information of the reference point to approximate its own location information. Combined with the motion parameters of the network device, pre-compensation is performed on the Doppler frequency shift of the uplink signal, and the uplink TA is calculated. This allows for pre-compensation of the Doppler frequency shift of the uplink signal and calculation of the uplink TA without relying on the terminal device's positioning.

[0231] Figure 6 This is a flowchart illustrating another communication method provided in an embodiment of this application. In this communication method, the network device sends first configuration information to the terminal device, and optionally, the terminal device sends first reporting information.Figure 6 The terminal device in the middle can be Figure 1 The term "terminal device" can also refer to the components within a terminal device (such as a processor, chip, or chip system). Figure 6 The network devices in the middle can be Figure 1 The term "network device" can also refer to the components within a network device (such as processors, chips, or chip systems). For example... Figure 6 As shown, the communication method 600 includes the following steps S601-S607, wherein S607 is optional.

[0232] S601, The network device sends the first configuration information to the terminal device.

[0233] This step is described in accordance with S301 and will not be repeated here.

[0234] S602. The terminal device measures the first signal of the network device and obtains the measured Doppler frequency shift value.

[0235] This step is based on S3021 and will not be repeated here.

[0236] S603. The terminal device obtains the target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of M reference points.

[0237] The terminal device calculates the deviation between the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of each of the M reference points, and selects the reference point with the smallest deviation as the target reference point. This step is the same as S3022 and will not be described again here.

[0238] S604. The terminal equipment uses the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount, or uses the measured Doppler frequency shift value as the uplink frequency offset pre-compensation amount, or uses the linear mean of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount.

[0239] This step is based on S3023 and will not be repeated here.

[0240] S605. The terminal device obtains the uplink TA based on the location information of the target reference point and the motion parameters of the network device.

[0241] This step is based on S3024 and will not be repeated here.

[0242] S606. The terminal device sends an uplink signal to the network device based on the uplink TA and the uplink frequency offset pre-compensation amount.

[0243] This step is described in S302 and will not be repeated here.

[0244] S607. The terminal device sends the first reporting information to the network device.

[0245] This step refers to the description of the first reported information in S302, and will not be repeated here.

[0246] Figure 7 This is a flowchart illustrating another communication method provided in an embodiment of this application. In this communication method, the network device sends first configuration information and first indication information to the terminal device. Optionally, the terminal device sends first reporting information. Figure 7 The terminal device in the middle can be Figure 1 The term "terminal device" can also refer to the components within a terminal device (such as a processor, chip, or chip system). Figure 7 The network devices in the middle can be Figure 1 The term "network device" can also refer to the components within a network device (such as processors, chips, or chip systems). For example... Figure 7 As shown, the communication method 700 includes the following steps S701-S707, wherein S707 is optional: S701, The network device sends the first configuration information and the first instruction information to the terminal device.

[0247] The first configuration information and the description of the first configuration information refer to S301, and will not be repeated here.

[0248] S702, the terminal device measures the first signal of the network device and obtains the measured Doppler frequency shift value.

[0249] This step is based on S3021 and will not be repeated here.

[0250] S703. The terminal device obtains the target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the P activated reference points.

[0251] The terminal device calculates the deviation between the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the P activated reference points, and selects the reference point with the smallest deviation as the target reference point. This step is the same as S3022 and will not be described again here.

[0252] S704. The terminal equipment uses the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount, or uses the measured Doppler frequency shift value as the uplink frequency offset pre-compensation amount, or uses the linear mean of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point as the uplink frequency offset pre-compensation amount.

[0253] This step is based on S3023 and will not be repeated here.

[0254] S705. The terminal device obtains the uplink TA based on the location information of the target reference point and the motion parameters of the network device.

[0255] This step is based on S3024 and will not be repeated here.

[0256] S706. The terminal device sends an uplink signal to the network device based on the uplink TA and the uplink frequency offset pre-compensation amount.

[0257] This step is described in S302 and will not be repeated here.

[0258] S707, The terminal device sends the first reporting information to the network device.

[0259] This step refers to the description of the first reported information in S302, and will not be repeated here.

[0260] like Figure 8 As shown in the illustration, an embodiment of this application provides a communication device. The communication device 800 may include a communication module 810. The communication module 810 can implement corresponding communication functions, which can be internal communication functions of the communication device 800 or communication functions between the communication device 800 and other devices. Optionally, the communication module 810 may also be referred to as a communication interface or a transceiver module. Optionally, the communication device 800 further includes a processing module 820. The processing module 820 can implement corresponding processing functions.

[0261] Optionally, the communication device 800 further includes a storage module 830, which can be used to store instructions and data; the processing module 820 can read the instructions and data in the storage module 830 so that the communication device 800 can implement the aforementioned method embodiment.

[0262] In one possible design, the communication device 800 may correspond to the terminal device in the above method embodiments, or a component (such as a circuit, chip, or chip system) configured in the terminal device. The communication device 800 can be used to execute the steps or processes performed by the terminal device in any of the above method embodiments.

[0263] For example, the communication module 810 is used to receive first configuration information, which includes the position information of M reference points and theoretical Doppler frequency shift values, where M is an integer greater than 1. The processing module 820 is used to measure the first signal of the network device to obtain a measured Doppler frequency shift value. The processing module 820 is used to obtain a target reference point based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of the M reference points. The processing module 820 is used to obtain an uplink frequency offset pre-compensation amount based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The processing module 820 is used to obtain the uplink TA based on the position information of the target reference point and the motion parameters of the network device. The communication module 810 is used to send an uplink signal based on the uplink TA and the uplink frequency offset pre-compensation amount.

[0264] In one possible implementation, the communication module 810 is used to send an uplink signal according to TA and uplink frequency offset pre-compensation amount when a first condition is met, wherein the first condition includes at least one of the following: the terminal device does not have a positioning function module installed, the terminal device cannot receive a positioning signal, the positioning function of the terminal device is unavailable, the positioning accuracy of the terminal device is less than or equal to an accuracy threshold, the positioning error of the terminal device is greater than or equal to an error threshold, and the time interval since the most recent acquisition of the location information of the terminal device is greater than or equal to a time threshold.

[0265] In one possible implementation, the communication module 810 is used to receive first indication information, which is used for at least one of the following: activating P reference points out of M reference points, and deactivating Q reference points out of M reference points; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0266] In one possible implementation, the communication module 810 is used to send first reporting information after establishing a connection with the network device, the first reporting information being used to indicate the target reference point.

[0267] In one possible implementation, the communication module 810 is used to send a first reporting information according to the instructions of the network device, or, when a second condition is met, send the first reporting information, or periodically send the first reporting information; wherein the second condition includes at least one of the following: first configuration information update, first indication information update, second indication information update, target reference point change, GNSS status of terminal device deterioration, RRC status of terminal device change, moving distance of terminal device exceeding range, terminal device entering or exiting energy-saving mode.

[0268] In one possible design, the communication device 800 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 800 can be used to perform the steps or processes performed by the network device in any of the above method embodiments.

[0269] For example, the communication module 810 is used to send first configuration information, which includes the position information of M reference points and theoretical Doppler frequency shift values, where M is an integer greater than 1. The communication module 810 is used to receive uplink signals according to the uplink TA and the uplink frequency offset pre-compensation amount; the uplink frequency offset pre-compensation amount is obtained based on at least one of the measured Doppler frequency shift value and the theoretical Doppler frequency shift value of the target reference point. The measured Doppler frequency shift value is obtained by the terminal device measuring the first signal of the network device. The target reference point is obtained based on the measured Doppler frequency shift value and the theoretical Doppler frequency shift values ​​of the M reference points. The uplink TA is obtained based on the position information of the target reference point and the motion parameters of the network device.

[0270] In one possible implementation, the communication module 810 is used to send first indication information, which is used for at least one of the following: activating P reference points out of M reference points, and deactivating Q reference points out of M reference points; P+Q=M, where P and Q are both integers greater than or equal to 0 and less than or equal to M.

[0271] In one possible implementation, the communication module 810 is used to receive first reporting information after establishing a connection with the terminal device. The first reporting information is used by the terminal device to indicate a target reference point.

[0272] Figure 9 This is a schematic diagram of another communication device provided in an embodiment of this application. The communication device 900 may be a chip, chip system, or processor, etc., used in network devices or terminal devices to implement the above-described methods. The communication device 900 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.

[0273] like Figure 9 As shown, the communication device 900 may include one or more processors 910, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 910 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 900 (e.g., a base station, baseband chip, user, user chip), execute software programs, and process data from the software programs.

[0274] In an alternative design, the processor 910 may also store instructions and data, which can be executed by the processor 910 to cause the communication device 900 to perform the methods described in the above method embodiments.

[0275] In another alternative design, the communication device 900 may include a communication interface 920 for implementing receiving and transmitting functions. For example, the communication interface 920 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.

[0276] Optionally, the communication device 900 may include one or more memories 930, which may store instructions that can be executed on the processor 910, causing the communication device 900 to perform the methods described in the above method embodiments. Optionally, the memories 930 may also store data. Optionally, the processor 910 may also store instructions and data. The processor 910 and the memories 930 may be provided separately or integrated together.

[0277] 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.

[0278] In one implementation, the communication device 900 can correspond to the terminal device in the above method embodiments and can be used to execute the various steps and processes executed by the terminal device in the above method embodiments. The processor 910 can be used to execute instructions stored in the memory 930, and when the processor 910 executes the instructions stored in the memory, the processor 910 is used to execute the various steps and processes of the above method embodiments corresponding to the terminal device.

[0279] In another implementation, the communication device 900 can correspond to the network device in the above method embodiments and can be used to execute the various steps and processes executed by the network device in the above method embodiments. The processor 910 can be used to execute the instructions stored in the memory 930, and when the processor 910 executes the instructions stored in the memory, the processor 910 is used to execute the various steps and processes of the above method embodiments corresponding to the network device.

[0280] It should be understood that the aforementioned processor can be one or more chips. For example, the processor 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.

[0281] 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.

[0282] According to the method provided in the embodiments of this application, this application also provides a processor, including: 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 the method described in the embodiments of this application.

[0283] 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.

[0284] 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.

[0285] The chip system may include input circuits or interfaces for transmitting information or data, and output circuits or interfaces for receiving information or data.

[0286] According to the method provided in the embodiments of this application, this application also provides a communication system, which includes the aforementioned terminal device and network device.

[0287] 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 terminal device or network device in any of the foregoing method embodiments.

[0288] 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 performed by the terminal device or network device in any of the foregoing method embodiments.

[0289] 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.

[0290] 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.

[0291] 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. A computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated.

[0292] 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.

[0293] 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.

[0294] 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 by comprising: The method is applied to a terminal device, and comprises: receiving first configuration information, the first configuration information comprising position information of M reference points and theoretical Doppler shift values, M being an integer greater than 1; sending an uplink signal according to an uplink time advance (TA) and an uplink frequency offset pre-compensation amount, the uplink frequency offset pre-compensation amount being obtained based on at least one of a measured Doppler shift value and a theoretical Doppler shift value of a target reference point, the measured Doppler shift value being obtained by the terminal device measuring a first signal of a network device, the target reference point being obtained based on the measured Doppler shift value and the theoretical Doppler shift values of the M reference points, and the uplink TA being obtained based on position information of the target reference point and a motion parameter of the network device.

2. The method of claim 1, wherein, The sending of the uplink signal according to the uplink TA and the uplink frequency offset pre-compensation amount comprises: in a case where a first condition is met, sending the uplink signal according to the uplink TA and the uplink frequency offset pre-compensation amount, wherein the first condition comprises at least one of the following: the terminal device is not installed with a positioning function module, the terminal device cannot receive a positioning signal, the positioning function of the terminal device is unavailable, the positioning accuracy of the terminal device is less than or equal to an accuracy threshold, the positioning error of the terminal device is greater than or equal to an error threshold, and a time interval from a time at which position information of the terminal device was last obtained is greater than or equal to a time threshold.

3. The method of claim 1, wherein, The method further comprises: receiving first indication information, the first indication information being used for at least one of the following: activating P reference points of the M reference points, deactivating Q reference points of the M reference points, and finally maintaining activated reference points to use the same distribution model as the M reference points; P+Q=M, P and Q are both integers greater than or equal to 0 and less than or equal to M.

4. The method of claim 3, wherein, The first indication information indicates a reference point of the M reference points in any of the following ways: The first indication information comprises an index of an activated or deactivated reference point, the index of the reference point being used to indicate a position of position information of the reference point in position information of the M reference points, or to indicate a position of a theoretical Doppler shift value of the reference point in theoretical Doppler shift values of the M reference points; or When the first configuration information further comprises an identifier of the M reference points, the first indication information comprises an identifier of an activated or deactivated reference point; or The first indication information indicates activated and deactivated reference points through a first bit map, one bit of the first bit map corresponding to one reference point, the one bit being a first value to indicate activation of the corresponding reference point, and the one bit being a second value to indicate deactivation of the corresponding reference point.

5. The method according to claim 3 or 4, characterized in that, The first indication information is carried through a medium access control control element (MAC CE) or downlink control information (DCI).

6. The method according to claim 3 or 4, characterized in that, The target reference point is a reference point of the P activated reference points, for which a theoretical Doppler shift value has a minimum deviation from the measured Doppler shift value.

7. The method according to claim 3 or 4, characterized in that, The method further comprises: After a connection is established with the network device, first reporting information is sent, the first reporting information being used to indicate the target reference point.

8. The method of claim 7, wherein, The first reporting information is carried by any of the following ways: Radio resource control (RRC) signaling, MAC CE, or uplink control information (UCI).

9. The method of claim 7, wherein, The first reporting information is also used to update at least one of the following: the first configuration information or the first indication information.

10. The method of claim 7, wherein, The first reporting information is sent in the following ways: The first reporting information is sent according to an indication of the network device, or the first reporting information is sent if a second condition is met, or the first reporting information is sent periodically. The second condition includes at least one of the following: the first configuration information is updated, the first indication information is updated, the target reference point changes, a global navigation satellite system (GNSS) state of the terminal device deteriorates, an RRC state of the terminal device changes, a moving distance of the terminal device exceeds a range, or the terminal device enters or exits an energy-saving mode.

11. The method of claim 1 or 2, wherein, The target reference point is a reference point in the M reference points with the smallest deviation between a theoretical Doppler shift value and a measured Doppler shift value.

12. The method according to any one of claims 1 to 4, characterized in that, The M reference points are distributed along a diameter in a moving direction of the network device within a beam coverage range of the network device.

13. The method according to any one of claims 1 to 4, characterized in that, The first configuration information further includes a timestamp, the timestamp being used to indicate a time at which the theoretical Doppler shift values of the M reference points are generated.

14. The method according to any one of claims 1 to 4, characterized in that, The first configuration information is carried by system information block (SIB) or RRC signaling.

15. A method of communication, comprising: The method is applied to a network device, and the method includes: Sending first configuration information, the first configuration information including position information and theoretical Doppler shift values of M reference points, M being an integer greater than 1. Receiving an uplink signal according to an uplink time advance (TA) and an uplink frequency offset pre-compensation amount, the uplink frequency offset pre-compensation amount being obtained based on at least one of a measured Doppler shift value or a theoretical Doppler shift value of a target reference point, the measured Doppler shift value being obtained by a terminal device measuring a first signal of the network device, the target reference point being obtained based on the measured Doppler shift value and the theoretical Doppler shift values of the M reference points, and the uplink TA being obtained based on position information of the target reference point and a motion parameter of the network device.

16. The method of claim 15, wherein, The method further includes: Sending first indication information, the first indication information being used to at least one of the following: activate P reference points in the M reference points, deactivate Q reference points in the M reference points, or finally keep activated reference points using the same distribution model as the M reference points; P+Q=M, P and Q are both integers greater than or equal to 0 and less than or equal to M.

17. The method of claim 16, wherein, The first indication information indicates a reference point in the M reference points in any of the following ways: The first indication information includes an index of the activated or deactivated reference point, and the index of the reference point is used to indicate a position of the reference point in the position information of the M reference points, or is used to indicate a position of a theoretical Doppler shift value of the reference point in the theoretical Doppler shift values of the M reference points. When the first configuration information further includes the identifiers of the M reference points, the first indication information includes the identifiers of the activated or deactivated reference points. The first indication information indicates the activated and deactivated reference points through a first bit map, one bit of the first bit map corresponds to one reference point, the bit is of a first value to indicate that the corresponding reference point is activated, and the bit is of a second value to indicate that the corresponding reference point is deactivated.

18. The method of claim 16 or 17, wherein, The first indication information is carried through a medium access control control element (MAC CE) or downlink control information (DCI).

19. The method of claim 16 or 17, wherein, The target reference point is a reference point with the smallest deviation between a theoretical Doppler shift value and the measured Doppler shift value in the P activated reference points.

20. The method of claim 16 or 17, wherein, The method further includes: After a connection is established with the terminal device, first reporting information is received, and the first reporting information is used to indicate the target reference point.

21. The method of claim 20, wherein, The first reporting information is carried through any of the following manners: Radio resource control (RRC) signaling, a medium access control control element (MAC CE), or uplink control information (UCI).

22. The method of claim 20, wherein, The first reporting information is used to update at least one of the following: the first configuration information or the first indication information.

23. The method of claim 15, wherein, The target reference point is a reference point with the smallest deviation between a theoretical Doppler shift value and the measured Doppler shift value in the M reference points.

24. The method of any one of claims 15-17, wherein, The M reference points are distributed on a diameter along a motion direction of the network device in a beam coverage range of the network device.

25. The method of any one of claims 15-17, wherein, The first configuration information further includes a time stamp, and the time stamp is used to indicate a time at which the theoretical Doppler shift values of the M reference points are generated.

26. The method of any one of claims 15-17, wherein, The first configuration information is carried through a system information block (SIB) or RRC signaling.

27. A communications device, characterized by The communication device includes a processor and a memory, and the memory stores instructions, and when the processor executes the instructions, the communication device performs the method in any of claims 1-26.

28. A computer readable storage medium having stored thereon a computer program or instructions, characterized in that, The computer program or instructions, when executed, cause a computer to perform the method in any of claims 1-26.

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