Cell synchronization method, system, storage medium and program product

Abstract

This application provides a cell synchronization method, system, storage medium, and program product, applicable to the field of communication technology. In response to an event of switching from a source cell to a target cell, a reference point timing difference is obtained. Based on a first transmission delay, a second transmission delay, the start time of the terminal's source cell frame, and the reference point timing difference, a downlink timing reference value for the target cell is calculated. If the signal quality of the source cell is greater than a preset signal quality threshold, the downlink timing reference value is determined as the downlink timing of the target cell. If the signal quality of the source cell is less than or equal to the preset signal quality threshold, the downlink timing reference value is used as a reference value to search for the synchronization signal of the target cell within a preset time window to obtain the downlink timing of the target cell. This reduces the processing latency of cell synchronization during cell synchronization and ensures service continuity.

Description

Technical Field

[0001] This application belongs to the field of communication technology, and in particular relates to a cell synchronization method, system, storage medium and program product. Background Technology

[0002] Non-terrestrial network (NTN) technology is a communication network based on non-terrestrial infrastructure such as satellites and high-altitude platforms. It aims to provide extensive communication coverage for users worldwide, including remote areas, maritime, and aviation scenarios, and can be used for voice and data communication in areas without terrestrial communication network coverage. In the low-Earth orbit (LEO) scenario of NTN, due to the high-speed motion of LEO satellites, the communication duration between the terminal and the satellite will not exceed a preset threshold. To ensure uninterrupted terminal communication, when the communication angle between the satellite and the ground reaches a certain threshold, the terminal needs to select a new satellite and connect to its corresponding cell.

[0003] To ensure service continuity, the time required for a terminal to switch to a new cell must be minimized. In existing technologies, when a terminal accesses a new cell, it needs to sequentially receive the primary synchronization signal and secondary synchronization signal of that cell, demodulate the Master Information Block (MIB) and System Information Block (SIB1) to obtain the complete superframe number and system frame number in order to complete the downlink synchronization process of the new cell.

[0004] However, in the existing NTN frame structure design, the synchronization signal and MIB are arranged relatively dispersedly, and the broadcast position of SIB1 is relatively sparse, which causes the terminal to spend a long time to complete signal reception and information parsing, resulting in a long cell synchronization processing delay and affecting the continuity of services. Summary of the Invention

[0005] This application provides a cell synchronization method, system, storage medium, and program product that can reduce the processing latency of cell synchronization and ensure service continuity during cell synchronization.

[0006] In a first aspect, embodiments of this application provide a cell synchronization method applied to a terminal, the method comprising:

[0007] In response to an event of switching from a source cell to a target cell, the reference point timing difference is obtained; wherein, the reference point timing difference is the timing deviation between the reference points of the source cell and the target cell;

[0008] The downlink timing reference value of the target cell is calculated based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal.

[0009] If the signal quality of the source cell is greater than the preset signal quality threshold, then the downlink timing reference value is determined as the downlink timing of the target cell.

[0010] If the signal quality of the source cell is less than or equal to the preset signal quality threshold, then the downlink timing reference value is used as the baseline value, and the synchronization signal of the target cell is searched within the preset time window to obtain the downlink timing of the target cell.

[0011] In one feasible implementation, obtaining the reference point timing difference includes:

[0012] Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the system information block; wherein, the reference point timing difference field is obtained by the network device from the received satellite signals and configured in the system information block;

[0013] And / or,

[0014] Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the radio resource control configuration information; wherein, the reference point timing difference field is configured by the network device in the radio resource control configuration information.

[0015] In one feasible implementation, before calculating the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the reference point timing difference, the method further includes:

[0016] Based on the source cell identifier and the target cell identifier, the ephemeris information, epoch time, and common timing advance of the source cell and the target cell are obtained from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, respectively. The ephemeris information field, epoch time field, and common timing advance field are configured by the network device in the radio resource control configuration information.

[0017] In one feasible implementation, the downlink timing reference value of the target cell is calculated based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the timing difference of the reference point, including:

[0018]

[0019] in, Indicates the downlink timing reference value; Indicates the start time of the source cell frame; Indicates the time difference between the reference point and the reference point; Indicates the second transmission delay; This indicates the first transmission delay.

[0020] In one feasible implementation, the downlink timing is obtained by searching for the synchronization signal of the target cell within a preset time window, using the downlink timing reference value as a base value, including:

[0021] The maximum timing error is determined based on the signal quality of the source cell, wherein the maximum timing error is inversely proportional to the signal quality of the source cell;

[0022] The preset time window is determined based on the downlink timing reference value and the maximum timing error;

[0023] Select the target synchronization signal whose time falls within the preset time window from the synchronization signals of the target cell;

[0024] The downlink timing of the target cell is obtained by searching within the target synchronization signal.

[0025] In one feasible implementation, before calculating the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the reference point timing difference, the method further includes:

[0026] Obtain the terminal coordinates, and calculate the first timing advance of the terminal based on the terminal coordinates, the ephemeris information and epoch time corresponding to the source cell;

[0027] The first transmission delay is calculated based on the common timing advance of the source cell and the first timing advance of the terminal.

[0028] Based on the terminal coordinates, the ephemeris information and epoch time corresponding to the target cell, calculate the second timing advance of the terminal.

[0029] The second transmission delay is calculated based on the common timing advance of the target cell and the second timing advance of the terminal.

[0030] Secondly, embodiments of this application provide a cell synchronization method applied to a network device, comprising:

[0031] The system information block is obtained from the received satellite signal, and a reference point timing difference field is configured in the system information block. The terminal obtains the reference point timing difference from the reference point timing difference field in the system information block based on the identifier of the target cell, and calculates the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0032] Configure a reference point timing difference field in the radio resource control configuration information so that the terminal can obtain the reference point timing difference from the reference point timing difference field in the radio resource control configuration information based on the identifier of the target cell, and calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0033] In one feasible implementation, it further includes:

[0034] The radio resource control configuration information includes an ephemeris information field, an epoch time field, and a common timing advance field. This allows the terminal to obtain the ephemeris information, epoch time, and common timing advance corresponding to the source and target cells from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, based on the source cell identifier and the target cell identifier, respectively. The terminal then calculates the first transmission delay and the second transmission delay based on the ephemeris information, epoch time, and common timing advance corresponding to the source and target cells, respectively. Based on the first transmission delay, the second transmission delay, the terminal's source cell frame start time, and the reference point timing difference, the terminal calculates the downlink timing reference value of the target cell.

[0035] Thirdly, embodiments of this application provide a cell synchronization system, which includes: a terminal and network equipment;

[0036] A terminal for performing cell synchronization using a cell synchronization method such as any one of the first aspects;

[0037] A network device for performing cell synchronization using a cell synchronization method as described in any of the second aspects.

[0038] Fourthly, embodiments of this application provide a terminal-side cell synchronization device, the device comprising:

[0039] The acquisition module is used to acquire the reference point timing difference in response to the event of switching from the source cell to the target cell; wherein, the reference point timing difference is the timing deviation between the reference points of the source cell and the target cell;

[0040] The calculation module is used to calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal.

[0041] The first processing module is used to determine the downlink timing reference value as the downlink timing of the target cell if the signal quality of the source cell is greater than a preset signal quality threshold.

[0042] The second processing module is used to search for the synchronization signal of the target cell within a preset time window if the signal quality of the source cell is less than or equal to a preset signal quality threshold, using the downlink timing reference value as a benchmark value, to obtain the downlink timing of the target cell.

[0043] Fifthly, embodiments of this application provide a network device-side cell synchronization apparatus, the apparatus comprising:

[0044] The first configuration module is used to obtain a system information block from the received satellite signal and configure a reference point timing difference field in the system information block, so that the terminal obtains the reference point timing difference from the reference point timing difference field in the system information block based on the identifier of the target cell, and calculates the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0045] The second configuration module is used to configure the reference point timing difference field in the radio resource control configuration information, so that the terminal can obtain the reference point timing difference from the reference point timing difference field in the radio resource control configuration information based on the identifier of the target cell, and calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0046] Sixthly, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement a cell synchronization method as described above.

[0047] In a seventh aspect, embodiments of this application provide a computer program product in which instructions, when executed by a processor of an electronic device, cause the electronic device to perform any of the above-mentioned cell synchronization methods.

[0048] This application provides a cell synchronization method, system, storage medium, and program product. Compared to existing technologies that require receiving the primary and secondary synchronization signals of the target cell and demodulating the main system module and system information block to obtain the complete superframe number and system frame number before completing the downlink synchronization process of a new cell, this application obtains the reference point timing difference in response to the event of switching from the source cell to the target cell. Based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame, and the reference point timing difference, it calculates the downlink timing reference value of the target cell. Using the known timing parameters of the source cell as a benchmark, it derives the downlink timing of the target cell. This is especially beneficial when the signal quality of the source cell is greater than the pre-defined... By setting a signal quality threshold, the downlink timing reference value is determined as the downlink timing of the target cell. This skips the traditional lengthy signal reception and decoding process and directly calculates the downlink timing of the target cell, reducing the processing latency of cell synchronization. If the signal quality of the source cell is less than or equal to the preset signal quality threshold, the downlink timing reference value is used as the benchmark value. Within a preset time window, the synchronization signal of the target cell is searched to obtain the downlink timing of the target cell. This reduces the amount of signal data that the terminal needs to receive and process, as well as the length of the time window for related calculations, thus reducing the amount of data processed and the computational complexity. It also reduces the processing latency of cell synchronization and ensures the continuity of services. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A flowchart illustrating the first cell synchronization method provided in this application embodiment is shown;

[0051] Figure 2 The timing relationship between the source cell and the target cell is shown;

[0052] Figure 3 A schematic diagram of the timing relationship is shown;

[0053] Figure 4 A flowchart illustrating the second cell synchronization method provided in an embodiment of this application is shown;

[0054] Figure 5 A flowchart illustrating the third cell synchronization method provided in this application embodiment is shown;

[0055] Figure 6 A flowchart illustrating the fourth cell synchronization method provided in this application embodiment is shown;

[0056] Figure 7A schematic diagram of the terminal-side cell synchronization device provided in this application is shown;

[0057] Figure 8 A schematic diagram of the network equipment-side cell synchronization device provided in this application is shown.

[0058] Figure 9 This application illustrates the cell synchronization system provided in this application;

[0059] Figure 10 A schematic diagram of the hardware structure of the terminal provided in this application is shown;

[0060] Figure 11 A schematic diagram of the hardware structure of the network device provided in this application is shown. Detailed Implementation

[0061] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0063] It should be noted that the acquisition, storage, use, and processing of data in this application embodiment all comply with the relevant provisions of national laws and regulations.

[0064] It should be noted that in the embodiments of this application, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, it does not mean that the applicant has used or necessarily used the solution.

[0065] Currently, in existing technologies, when performing cell synchronization, the terminal needs to obtain the complete superframe number and frame number to achieve accurate timing alignment. These two types of numbers are split into multiple segments and stored separately in different signal or information blocks. The terminal needs to receive the primary synchronization signal and secondary synchronization signal of the new cell to be accessed, obtain the intra-frame deviation and the lower 3 bits of the frame number based on the primary synchronization signal and secondary synchronization signal, then parse the MIB to extract the higher 7 bits of the frame number and the higher 2 bits of the superframe, and finally parse the SIB1 to obtain the higher 8 bits of the superframe. All binary segments need to be collected and spliced ​​into a complete superframe number and frame number before downlink synchronization of the new cell can be completed.

[0066] In the frame structure design of NTN, the primary and secondary synchronization signals storing the lower 3 bits of the frame number, the MIB storing the higher 7 bits of the frame number, and the higher 2 bits of the superframe number are inherently scattered. Furthermore, the SIB1 storing the higher 8 bits of the superframe number has a long broadcast period and a relatively sparse position. This causes the terminal to wait for multiple frame cycles to collect all binary segments, resulting in a latency on the order of seconds. Consequently, when accessing a new cell from the current cell, the intermediate latency is long, affecting service continuity. This is particularly problematic for voice services in Internet of Things Non-Terrestrial Network (IoT NTN) scenarios, severely impacting their continuity.

[0067] To address the problems in existing technologies, embodiments of this application provide a cell synchronization method, system, storage medium, and program product. In response to an event of switching from a source cell to a target cell, the downlink timing reference value of the target cell is calculated based on a first transmission delay, a second transmission delay, the start time of the source cell frame of the terminal, and a reference point timing difference. The downlink timing of the target cell is derived using known timing parameters of the source cell as a benchmark. If the signal quality of the source cell is greater than a preset signal quality threshold, the downlink timing reference value is directly determined as the downlink timing of the target cell. This skips the traditional lengthy signal reception and decoding process, directly obtaining the downlink timing of the target cell and reducing the processing latency of cell synchronization. If the signal quality of the source cell is less than or equal to the preset signal quality threshold, the downlink timing reference value is used as a benchmark value, and the synchronization signal of the target cell is searched within a preset time window to obtain the downlink timing of the target cell. This reduces the amount of data the terminal needs to process and lowers computational complexity, thus also reducing the processing latency of cell synchronization and ensuring service continuity.

[0068] The following section first introduces a cell synchronization method provided in the embodiments of this application.

[0069] Figure 1A flowchart illustrating the first cell synchronization method provided in this application embodiment is shown. This method is applied to a terminal, such as... Figure 1 As shown, the method may include the following steps:

[0070] S101: In response to an event of switching from the source cell to the target cell, obtain the reference point timing difference; wherein, the reference point timing difference is the timing deviation between the reference points of the source cell and the target cell;

[0071] S102: Calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal.

[0072] S103: If the signal quality of the source cell is greater than the preset signal quality threshold, then the downlink timing reference value is determined as the downlink timing of the target cell;

[0073] S104: If the signal quality of the source cell is less than or equal to the preset signal quality threshold, then the downlink timing reference value is used as the base value, and the synchronization signal of the target cell is searched within the preset time window to obtain the downlink timing of the target cell.

[0074] In this embodiment, compared to the prior art which requires receiving the primary and secondary synchronization signals of the target cell and demodulating the main system module and system information block to obtain the complete superframe number and system frame number in order to complete the downlink synchronization process of the new cell, this application obtains the reference point timing difference in response to the event of switching from the source cell to the target cell. Based on the first transmission delay, the second transmission delay, the terminal's source cell frame start time, and the reference point timing difference, it calculates the downlink timing reference value of the target cell. Using the known timing parameters of the source cell as a benchmark, it derives the downlink timing of the target cell. If the signal quality of the source cell is greater than a preset signal quality threshold, then the downlink timing is... The downlink timing reference value is determined as the downlink timing of the target cell. This can skip the traditional lengthy signal reception and decoding process and directly calculate the downlink timing of the target cell, reducing the processing latency of cell synchronization. If the signal quality of the source cell is less than or equal to the preset signal quality threshold, the downlink timing reference value is used as the benchmark value. The synchronization signal of the target cell is searched within the preset time window to obtain the downlink timing of the target cell. This can reduce the amount of signal data that the terminal needs to receive and process, as well as the length of the time window for related calculations, thereby reducing the amount of data processed and the computational complexity. It also reduces the processing latency of cell synchronization and ensures the continuity of services.

[0075] The specific implementation methods for each of the above steps are described below.

[0076] S101: In response to an event of switching from the source cell to the target cell, obtain the reference point timing difference;

[0077] In this embodiment, the core of the solution lies in using the ephemeris information of the source cell and the target cell to calculate the downlink timing of the target cell based on the known information of the source cell. However, in a low-Earth orbit (LEO) NTN scenario, the reference points of the source cell and the target cell are their own independent timing bases, resulting in a natural timing deviation. If this deviation is ignored and the downlink timing of the target cell is calculated directly, the timing result will be biased, leading to synchronization failure or service interruption. Therefore, before calculating the downlink timing of the target cell, it is necessary to first obtain the timing difference of the reference points to eliminate the impact of clock asynchrony between the two reference points.

[0078] In this context, the reference point refers to the timing reference point of the cell. For low-Earth orbit satellite cells, the reference point can be the satellite's own high-precision reference clock point. For ground-assisted cells, the reference point can be a preset fixed ground synchronization point. Its core function is to provide a unified time reference for signals transmitted within the cell. Reference point timing refers to the continuous and stable time sequence generated by the reference point based on its own high-precision clock. It serves as the original reference for the timing of all signal transmissions within the cell. Therefore, the reference point timing difference refers to the timing deviation between the reference points of the source cell and the target cell. It consists of three parts: superframe number deviation, frame number deviation, and intra-frame deviation, with the intra-frame deviation having an accuracy of 1 / 19200000.0 second. The reference point timing difference is obtained through inter-satellite links. Because the source and target cells are not synchronized, the reference point timing difference is not zero.

[0079] In one example, the event of switching from the source cell to the target cell includes, but is not limited to, the following scenarios: handover scenario, cell reselection scenario, and Radio Resource Control (RRC) reconstruction scenario. Specifically, the handover scenario occurs when the satellite elevation angle of the source cell currently accessed by the terminal drops to a preset threshold, or the signal quality of the source cell falls below a preset threshold, triggering a cell handover and requiring access to a new cell. The cell reselection scenario occurs when the terminal, in an idle state, detects that the signal quality of a nearby target cell is better than that of the current source cell, thus triggering a cell reselection. The RRC reconstruction scenario occurs when the connection between the terminal and the source cell is interrupted due to obstruction, interference, or other reasons, requiring access to a target cell with better signal quality through an RRC reconstruction process.

[0080] In one example, to quickly and reliably obtain the reference point timing difference between the source cell and the target cell, one specific implementation of obtaining the reference point timing difference is as follows:

[0081] Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the system information block; wherein, the reference point timing difference field is obtained by the network device from the received satellite signals and configured in the system information block.

[0082] In this application embodiment, the system information block is the neighbor cell parameter information periodically broadcast by the source cell. In one example, the system information block can be SIB33. During the networking phase, this application obtains the system information block from the received satellite signals through network devices and adds a reference point timing difference field to the system information block, which can be stored according to the correspondence between cell identifier and reference point timing difference.

[0083] In one example, when the terminal communicates with the source cell, it can receive SIB33 and cache the reference point timing differences of all neighboring cells stored therein. When a handover is required, the terminal can directly obtain the reference point timing difference of the target cell from the reference point timing differences of all neighboring cells stored in the terminal according to the identifier of the target cell.

[0084] Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the radio resource control configuration information; wherein, the reference point timing difference field is configured by the network device in the radio resource control configuration information.

[0085] In this embodiment, the radio resource control configuration information is a dedicated configuration message sent by the network device to the terminal when the terminal triggers cell handover. In the low-Earth orbit NTN scenario, SIB33 may be obstructed or interfered with, causing the terminal to fail to parse the information it carries. Therefore, when the terminal fails to parse the information carried by SIB33, the network device can send the reference point timing difference to the terminal through the RRC configuration information. The terminal does not need to rely on the broadcast reception of SIB33, but only needs to parse this dedicated configuration message to obtain the reference point timing difference, ensuring that the synchronization process is not interrupted.

[0086] In one example, the network device can determine the target cell based on the measurement report reported by the terminal. The network device calculates the reference point timing difference by timing the reference points corresponding to the source cell and the target cell respectively. Then, the network device encapsulates the reference point timing difference into the RRC configuration information generated specifically for this terminal.

[0087] In one example, a reference point timing field can also be added to the aforementioned system information block and radio resource control configuration information. Based on the source cell identifier and the target cell identifier, the real-time reference points corresponding to the source cell and the target cell can be obtained from the system information block or the RRC configuration information. The reference point timing difference between the source cell and the target cell can be calculated by measuring the difference between the two.

[0088] In this embodiment, by pre-configuring the reference point timing difference field in the system information block, the terminal can receive and cache the reference point timing differences corresponding to all neighboring cells in advance after accessing the source cell. This allows for rapid retrieval of the corresponding reference point timing difference from the local cache based on the target cell identifier when a cell replacement event is triggered, improving the calculation speed of the downlink timing reference value and thus shortening the overall latency of cell synchronization. Furthermore, by pre-configuring the reference point timing difference field in the radio resource control configuration information, even when SIB33 cannot be received or parsed normally due to satellite obstruction, signal interference, or other factors in LEO NTN scenarios, the terminal can still accurately obtain the reference point timing difference corresponding to the current target cell by receiving the radio resource control configuration information directed by the network device. This ensures that the calculation process of the downlink timing reference value of the target cell is not interrupted, avoiding cell synchronization failure due to missing parameters, thereby improving the reliability of cell synchronization in LEO NTN scenarios.

[0089] S102: Calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal.

[0090] In this embodiment, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal. The source cell frame start time of the terminal refers to the start time point at which the terminal actually receives the downlink data frame from the source cell. Through the timing correlation between the reference points of the source cell and the target cell, the relationship between the first transmission delay, the second transmission delay, the timing difference of the reference points, the source cell frame start time of the terminal, and the downlink timing reference value of the target cell can be derived, thereby enabling the downlink timing reference value of the target cell to be calculated based on the source cell frame start time.

[0091] In one example, the start time of the source cell frame of the terminal can be obtained by receiving the downlink synchronization and pilot signals of the source cell.

[0092] To facilitate understanding of the calculation process of the downlink timing reference value, Figure 2 The timing relationship between the source cell and the target cell is shown, such as... Figure 2 As shown, in order to understand the calculation formula for the downlink timing reference value, refer to... Figure 2 ,in It is a precise moment recorded locally by the terminal, that is, the starting moment when it receives the current source cell downlink frame number N, i.e., the instant at which the source cell downlink frame is received; since If the signal arrives at the terminal, then subtracting the transmission time from the source cell reference point to the terminal will give the time when the source cell reference point emitted the signal. :

[0093] (1)

[0094] in, This indicates the time when the source cell reference point sends a signal with frame number N; This indicates the start time of the source cell frame, that is, the time when the terminal receives the source cell signal with frame number N; This represents the first transmission delay, which is the delay in the signal being transmitted from the reference point of the source cell to the terminal.

[0095] The reference point timing difference between the source cell reference point and the target cell reference point is: That is, the time difference between the source cell reference point and the target cell reference point is The time when the source cell reference point sends a signal with frame number N minus the timing difference of the reference point is: This allows us to obtain the time when the target cell reference point sends a signal with frame number N. :

[0096] (2)

[0097] in, This indicates the time when the target cell reference point sends a signal with frame number N; This indicates the time when the source cell reference point sends a signal with frame number N; This indicates the time difference between the reference point and the reference point.

[0098] Therefore, the time for transmitting a signal with frame number N from the target cell reference point In addition, there is a second transmission delay in the signal transmission from the target cell reference point to the terminal. This will give you the downlink timing reference value for the target cell:

[0099] (3)

[0100] in, Indicates the downlink timing reference value; Indicates the time when the target cell reference point sends a signal with frame number N; This indicates the second transmission delay.

[0101] Therefore, by combining the above formulas (1) to (3), we can obtain the relationship between the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, the timing difference of the reference point, and the downlink timing reference value of the target cell:

[0102] (4)

[0103] in, Indicates the downlink timing reference value; Indicates the start time of the source cell frame; Indicates the time difference between the reference point and the reference point; Indicates the second transmission delay; This indicates the first transmission delay.

[0104] In this embodiment, the calculation formula for the downlink timing reference value can be derived by considering the relationship between the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, the timing difference of the reference point, and the downlink timing reference value of the target cell. Thus, the downlink timing reference value of the target cell can be directly obtained based on the start time of the source cell frame, without needing to sequentially receive the primary synchronization signal and secondary synchronization signal of the cell, demodulate the main system module and system information block to obtain the complete superframe number and system frame number. This avoids the second-level waiting delay caused by the scattered arrangement of synchronization signals and MIBs and the relatively sparse SIB1 broadcast position, thereby reducing the processing delay of cell synchronization.

[0105] In one example, to obtain the first transmission delay and the second transmission delay, before step S102, the following is also included:

[0106] Obtain the terminal coordinates, and calculate the terminal's first timing advance based on the terminal coordinates, the ephemeris information corresponding to the source cell, and the epoch time.

[0107] In this embodiment, the first timing advance of the terminal refers to the round-trip propagation time of the signal between the terminal, the source cell, and the satellite. The first timing advance of the terminal can be obtained by using the terminal coordinates, the ephemeris information corresponding to the source cell, and the epoch time.

[0108] In one example, the terminal can obtain its own coordinates through the built-in Global Positioning System (GPS), BeiDou Navigation Satellite System, or other positioning modules.

[0109] In another example, the terminal can obtain the ephemeris information and epoch time of the source cell by reading the source cell system block SIB33.

[0110] In another example, to ensure the timeliness of the terminal's first timing advance, after responding to the event of switching from the source cell to the target cell, the terminal obtains the terminal coordinates, the ephemeris information and epoch time corresponding to the source cell, and calculates the first timing advance.

[0111] The first transmission delay is calculated based on the common timing advance of the source cell and the first timing advance of the terminal.

[0112] In this embodiment, the common timing advance corresponding to the source cell refers to the round-trip time of the signal between the satellite and the source cell reference point, while the first transmission delay refers to the delay of the signal from the source cell reference point to the terminal. Therefore, the formula for calculating the first transmission delay is:

[0113] (5)

[0114] in, Indicates the first transmission delay; This indicates the public timing advance amount corresponding to the source cell; This indicates the first timing advance of the terminal.

[0115] Based on the terminal coordinates, the ephemeris information and epoch time corresponding to the target cell, the second timing advance of the terminal is calculated.

[0116] In this embodiment, the first timing advance of the terminal refers to the round-trip propagation time of the signal between the terminal, the target cell, and the satellite. Therefore, the terminal coordinates, the ephemeris information and epoch time corresponding to the target cell are obtained and the second timing advance of the terminal is calculated using the same calculation method as the second timing advance.

[0117] In one example, the terminal can also obtain the ephemeris information and epoch time of the target cell by reading the target cell system block SIB33.

[0118] In another example, also to ensure the timeliness of the terminal's second timing advance, after responding to the event of switching from the source cell to the target cell, the terminal obtains the terminal coordinates, the ephemeris information and epoch time corresponding to the target cell, and calculates the second timing advance.

[0119] The second transmission delay is calculated based on the common timing advance of the target cell and the second timing advance of the terminal.

[0120] In this embodiment, the common timing advance corresponding to the target cell refers to the round-trip time of the signal between the satellite and the target cell reference point, while the second transmission delay refers to the delay of the signal transmission from the target cell reference point to the terminal. Therefore, the formula for calculating the second transmission delay is:

[0121] (6)

[0122] in, Indicates the second transmission delay; This indicates the advance timing for the target community. This indicates the second timing advance of the terminal.

[0123] To clearly illustrate the relationship between transmission delay, common timing advance, and terminal timing advance Figure 3 A timing relationship diagram is shown, such as Figure 3 As shown in the figure, this diagram depicts the signal transmission path between the satellite, reference point, and terminal in a non-terrestrial network communication scenario: the uplink signal sent by the terminal is relayed by the satellite and finally reaches the gateway through the reference point; the downlink signal follows the opposite path, from the gateway through the reference point to the satellite, and then relayed by the satellite to the terminal. The Common TA marked in the figure represents the common timing advance for the cell, specifically the round-trip propagation time of the signal from the reference point to satellite 1 and back. This parameter is pre-calculated and configured by the network equipment through the ground telemetry and control link and is a fixed parameter shared by all terminals within the cell's coverage area. The UE TA 1 and UE TA 2 marked in the figure correspond to the terminal timing advance for terminal 1 and terminal 2, respectively. Specifically, they represent the round-trip propagation time of the signal from the corresponding terminal to the satellite and back. Due to the different distances between terminal 1 and terminal 2 and the satellite, their terminal timing advance values ​​differ, representing personalized round-trip delay parameters for each terminal. Based on the first transmission delay and the second transmission delay defined in this application, it can be known that the first transmission delay and the second transmission delay are the time for the reference point to be transmitted to the terminal, which is therefore half of the sum of the common timing advance and the terminal timing advance.

[0124] In this embodiment, by analyzing the composition relationship between the common timing advance and the terminal timing advance, it can be concluded that the first transmission delay is half of the sum of the common timing advance corresponding to the source cell and the terminal's first timing advance, and the second transmission delay is half of the sum of the common timing advance corresponding to the target cell and the terminal's second timing advance. Therefore, by calculating the terminal's first timing advance, the first transmission delay can be obtained based on the terminal's first timing advance and the common timing advance corresponding to the source cell, and by calculating the terminal's second timing advance, the second transmission delay can be obtained based on the terminal's second timing advance and the common timing advance corresponding to the target cell, thereby providing accurate and reliable delay parameters for subsequently calculating the downlink timing reference value of the target cell.

[0125] In one example, to avoid failures in acquiring ephemeris information, epoch time, and common timing advance, the calculation of the first and second transmission delays includes:

[0126] Based on the source cell identifier and the target cell identifier, the ephemeris information, epoch time, and common timing advance of the source cell and the target cell are obtained from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, respectively. The ephemeris information field, epoch time field, and common timing advance field are configured by the network device in the radio resource control configuration information.

[0127] In this embodiment, the network device obtains the ephemeris information, epoch time, and corresponding common timing advance of the source cell and the target cell through the satellite telemetry and control link, and writes these parameters into the radio resource control configuration information. After the terminal triggers the event of switching from the source cell to the target cell, the terminal can obtain the corresponding ephemeris information, epoch time, and common timing advance based on the identifier of the source cell and the identifier of the target cell, respectively.

[0128] In one example, the network device can determine the source cell and the target cell based on the measurement report reported by the terminal. After determining the source cell and the target cell, the ephemeris information, epoch time and the corresponding common timing advance of the source cell and the target cell are written into the radio resource control configuration information.

[0129] In one example, the ephemeris information, epoch time, and common timing advance in the radio resource control configuration information are in the same format as those in the system information block.

[0130] In this embodiment of the application, in order to avoid the terminal failing to parse the information carried by the radio resource control configuration information due to obstruction or interference, this application adds an ephemeris information field, an epoch time field, and a common timing advance field to the radio resource control configuration information. This ensures that when the terminal receives the handover command, it can directly obtain all the key parameters required to calculate the transmission delay from the dedicated signaling at once. This avoids the terminal failing to parse the information in time due to environmental interference, and can still perform fast synchronization calculation based on the complete information carried by the radio resource control configuration information, thereby improving the success rate of the handover process.

[0131] S103: If the signal quality of the source cell is greater than the preset signal quality threshold, then the downlink timing reference value is determined as the downlink timing of the target cell.

[0132] In this embodiment, the error of the downlink timing reference value mainly comes from the start time of the source cell frame of the terminal. Because when a new cell needs to be accessed, the signal of the source cell may be relatively poor, resulting in an error in the start time of the source cell frame. Therefore, by judging the signal quality of the source cell, if the signal quality of the source cell is greater than the preset signal quality threshold, the start time of the source cell frame is considered to be reliable enough. At this time, the downlink timing reference value can be determined as the downlink timing of the target cell.

[0133] In one example, signal quality can be determined by the signal-to-interference plus noise ratio (SINR). The terminal can detect the SINR of the source cell signal using its radio frequency module.

[0134] S104: If the signal quality of the source cell is less than or equal to the preset signal quality threshold, then the downlink timing reference value is used as the base value, and the synchronization signal of the target cell is searched within the preset time window to obtain the downlink timing of the target cell.

[0135] In this embodiment, when the signal quality of the source cell is less than or equal to a preset signal quality threshold, the calculated downlink timing reference value has a large error. If this downlink timing reference value is directly used as the downlink timing for the target cell, it may cause the terminal and the target cell to fail to establish downlink synchronization, leading to serious problems such as handover failure and service interruption. However, since this downlink timing reference value is calculated based on precise geometric information such as the ephemeris of the source and target cells and the terminal's location, its error mainly stems from poor signal quality, and therefore its value is still close to the actual synchronization position. Therefore, this application uses the downlink timing reference value as a benchmark value, determines the maximum timing error through the source cell signal quality, and then dynamically determines a preset time window that is much smaller than the traditional synchronization search range. The terminal only needs to search for the synchronization signal of the target cell within this preset time window to quickly lock the accurate synchronization position.

[0136] Figure 4 A flowchart illustrating the second cell synchronization method provided in this application is shown, as follows: Figure 4 As shown, S401: Calculate the downlink timing reference value of the target cell; S402: Determine whether the downlink timing reference value is directly available; S403: Determine the downlink timing reference value as the downlink timing of the target cell; S404: Based on the downlink timing reference value as the benchmark value, find the downlink timing of the target cell.

[0137] S401: Calculate the downlink timing reference value of the target cell; calculate the downlink timing reference value of the target cell using the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point.

[0138] S402: Determine whether the downlink timing reference value is directly available; if the signal quality of the source cell is greater than the preset signal quality threshold, step S403 can be executed directly, otherwise step S404 will be executed.

[0139] S403: Determine the downlink timing reference value as the downlink timing of the target cell.

[0140] S404: Based on the downlink timing reference value, find the downlink timing of the target cell.

[0141] In one example, to obtain accurate downlink timing of the target cell even under poor signal quality conditions, a specific implementation of step S104 is as follows:

[0142] The maximum timing error is determined based on the signal quality of the source cell, where the maximum timing error is inversely proportional to the signal quality of the source cell.

[0143] In this embodiment, the signal quality of the source cell directly affects the start time of the source cell frame of the terminal. The worse the signal quality, the greater the error. The maximum timing error is the maximum range that the predicted downlink timing reference value may deviate from the true value. Therefore, the maximum timing error can be determined based on the signal quality of the source cell.

[0144] In one example, the mapping relationship between signal quality and maximum timing error can be determined through simulation. For instance, in a simulation environment, scenarios where signals propagate with different signal qualities are simulated, and the detection error of the terminal at the start time of the source cell frame is repeatedly tested in each scenario. The maximum deviation range of the downlink timing reference value for different signal qualities is statistically analyzed, and a mapping relationship table between the signal quality of the source cell and the maximum timing error is established based on the simulation results.

[0145] The preset time window is determined based on the downlink timing reference value and the maximum timing error.

[0146] In this embodiment, the downlink timing reference value is the time center, the start time of the preset time window is the downlink timing reference value minus the maximum timing error, and the end time of the preset time window is the downlink timing reference value plus the maximum timing error. That is, the window length is twice the maximum timing error plus 1, so as to cover all sampling points.

[0147] Select the target synchronization signal whose time falls within the preset time window from the synchronization signals of the target cell.

[0148] In this embodiment of the application, the synchronization signal received by the terminal contains a large number of invalid signals outside the window. Capturing the signal within the window can reduce the amount of data processed by the terminal, reduce the consumption of computing resources, and improve the search speed. Therefore, the target synchronization signal is selected from the synchronization signal of the target cell, and the time of the signal falls within the preset time window.

[0149] The downlink timing of the target cell is obtained by searching within the target synchronization signal.

[0150] In this embodiment of the application, the downlink timing of the target cell can be obtained by searching within the target synchronization signal.

[0151] In one example, a time-domain correlation operation is performed between the target synchronization signal and a copy of the standard synchronization signal pre-stored in the terminal to search for the peak value of the correlation value. The time corresponding to the peak value is the precise downlink timing.

[0152] In this embodiment, the maximum timing error is determined based on the signal quality of the source cell, and a preset time window is determined based on the downlink timing reference value and the maximum timing error. This allows the synchronization search to be performed within the preset time window, avoiding the huge time overhead caused by blindly searching over the entire uncertain time range in the traditional synchronization process. Furthermore, since the search range is strictly limited to the maximum error range near the predicted value, the amount of signal data that the terminal needs to receive and process, as well as the length of the time window for related calculations, are reduced. As a result, the amount of data processed and the computational complexity are also reduced, thus reducing the downlink timing determination time of the target cell and ensuring service continuity.

[0153] Figure 5 A flowchart illustrating the third cell synchronization method provided in this application is shown. Figure 5 As shown, this method is applied to a network device and may include the following steps:

[0154] S501: Obtain a system information block from the received satellite signal and configure a reference point timing difference field in the system information block, so that the terminal obtains the reference point timing difference from the reference point timing difference field in the system information block based on the identifier of the target cell, and calculates the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0155] In this embodiment, the system information block is a public parameter carrier for the periodic broadcast of the source cell. By configuring a reference point timing difference field in it, all terminals accessing the source cell can read the cache in advance, without having to send it separately to each terminal, thus reducing network-side overhead.

[0156] In one example, during the networking phase, the network device obtains SIB33 from the satellite signal and configures a reference point timing difference field therein, so that the source cell broadcasts SIB33 containing this field at a preset period for the terminal to receive.

[0157] S502: Configure a reference point timing difference field in the radio resource control configuration information so that the terminal can obtain the reference point timing difference from the reference point timing difference field in the radio resource control configuration information based on the identifier of the target cell, and calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0158] In the embodiments of this application, in scenarios where the terminal has just accessed the source cell or the SIB33 broadcast is interfered with, the terminal may not obtain the reference point timing difference in SIB33. Configuring this field in the radio resource control configuration information can enable targeted distribution during handover, ensuring that the terminal can obtain the reference point timing difference and avoiding synchronization failure.

[0159] In one example, after the terminal triggers a cell handover, the network device adds the corresponding reference point timing difference field to the radio resource control configuration information based on the target cell identifier and sends it to the terminal in a targeted manner.

[0160] In one example, the reference point timing difference field configured in the radio resource control configuration information has the same format as the reference point timing difference field configured in the system information block, so the terminal does not need to develop two sets of parsing logic, reducing the complexity of the terminal.

[0161] In this embodiment, the network-side device obtains a system information block from the received satellite signal and configures a reference point timing difference (RPD) field in the system information block. This allows the terminal to receive and cache the RPDs of all neighboring cells in advance after accessing the source cell. Consequently, when a cell replacement event is triggered, the terminal can quickly obtain the corresponding RPD from the local cache based on the target cell identifier, improving the calculation speed of the downlink timing reference value. Furthermore, the network device configures the RPD field in the radio resource control configuration information, ensuring that even if the terminal does not obtain the RPD in SIB33, it can still accurately obtain the RPD corresponding to the current target cell by receiving the radio resource control configuration information sent by the network device. This ensures that the calculation process of the downlink timing reference value of the target cell is not interrupted, guaranteeing the success rate of cell synchronization.

[0162] In one example, since SIB33 already contains the ephemeris information and epoch time of each neighboring cell, as well as the common timing advance, to ensure the success rate of cell synchronization, it also includes:

[0163] The radio resource control configuration information includes an ephemeris information field, an epoch time field, and a common timing advance field. This allows the terminal to obtain the ephemeris information, epoch time, and common timing advance corresponding to the source and target cells from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, based on the source cell identifier and the target cell identifier, respectively. The terminal then calculates the first transmission delay and the second transmission delay based on the ephemeris information, epoch time, and common timing advance corresponding to the source and target cells, respectively. Based on the first transmission delay, the second transmission delay, the terminal's source cell frame start time, and the reference point timing difference, the terminal calculates the downlink timing reference value of the target cell.

[0164] In this embodiment of the application, the network device obtains the ephemeris information and epoch time of the source cell and the target cell in real time through the satellite telemetry and control link, and calculates the common timing advance of the source cell and the target cell based on the satellite orbital altitude and satellite-to-ground distance. The network device configures these parameters in the radio resource control configuration information, so that after the terminal triggers cell handover, the network device sends the radio resource control configuration information containing these parameters to the terminal.

[0165] In this embodiment, ephemeris information, epoch time, and common timing advance are the core parameters for the terminal to calculate transmission delay. To avoid the terminal failing to parse the information carried by SIB33 due to obstruction or interference, this application configures the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information through network devices. This ensures that the terminal can always obtain the above parameters, ensures that the calculation process of the downlink timing reference value of the target cell is not interrupted, and guarantees the success rate of cell synchronization.

[0166] Figure 6 A flowchart illustrating the fourth cell synchronization method provided in this application is shown, as follows: Figure 6 As shown, the method includes the following steps:

[0167] S601: The network device obtains the system information block from the received satellite signal and configures the reference point timing difference field in the system information block.

[0168] S602: Network devices configure the reference point timing difference field in the radio resource control configuration information.

[0169] S603: Network devices configure the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information.

[0170] S604: The terminal obtains the reference point timing difference from the reference point timing difference field in the system information block or radio resource control configuration information based on the identifier of the target cell.

[0171] S605: Based on the identifier of the source cell and the identifier of the target cell, the terminal obtains the ephemeris information, epoch time, and common timing advance corresponding to the source cell and the target cell from the ephemeris information field, epoch time field, and common timing advance field in the system information block or radio resource control configuration information, respectively.

[0172] S606: The terminal calculates the first transmission delay and the second transmission delay based on the terminal coordinates, ephemeris information field, epoch time field and common timing advance field respectively;

[0173] S607: The terminal calculates the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame, and the timing difference of the reference point.

[0174] S608: If the signal quality of the terminal in the source cell is greater than the preset signal quality threshold, then the downlink timing reference value is determined as the downlink timing of the target cell.

[0175] S609: If the signal quality of the terminal in the source cell is less than or equal to the preset signal quality threshold, then the downlink timing reference value is used as the base value to search for the synchronization signal of the target cell within the preset time window to obtain the downlink timing of the target cell.

[0176] Figure 7 A schematic diagram of the terminal-side cell synchronization device provided in this application is shown. Figure 7 As shown, the terminal-side cell synchronization device 700 provided in this application includes:

[0177] The acquisition module 701 is used to acquire the reference point timing difference in response to the event of switching from the source cell to the target cell; wherein, the reference point timing difference is the timing deviation between the reference points of the source cell and the target cell;

[0178] The calculation module 702 is used to calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal.

[0179] The first processing module 703 is used to determine the downlink timing reference value as the downlink timing of the target cell if the signal quality of the source cell is greater than a preset signal quality threshold.

[0180] The second processing module 704 is used to search for the synchronization signal of the target cell within a preset time window if the signal quality of the source cell is less than or equal to a preset signal quality threshold, using the downlink timing reference value as a base value, to obtain the downlink timing of the target cell.

[0181] In one example, obtaining module 701 includes:

[0182] The first acquisition submodule is used to obtain the reference point timing difference from the reference point timing difference field in the system information block based on the identifier of the target cell; wherein, the reference point timing difference field is obtained by the network device from the received satellite signals and configured in the system information block;

[0183] The second acquisition submodule is used to obtain the reference point timing difference from the reference point timing difference field in the radio resource control configuration information based on the identifier of the target cell; wherein the reference point timing difference field is configured by the network device in the radio resource control configuration information.

[0184] In one example, the terminal-side cell synchronization device 700 also includes:

[0185] The acquisition module is also used to acquire the ephemeris information, epoch time, and common timing advance of the source cell and the target cell respectively from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information based on the source cell identifier and the target cell identifier; wherein the ephemeris information field, epoch time field, and common timing advance field are configured by the network device in the radio resource control configuration information.

[0186] In one example, the second processing module 704 includes:

[0187] The first determining submodule is used to determine the maximum timing error based on the signal quality of the source cell, wherein the maximum timing error is inversely proportional to the signal quality of the source cell;

[0188] The second determining submodule is used to determine a preset time window based on the downlink timing reference value and the maximum timing error.

[0189] The selection submodule is used to select the target synchronization signal whose time falls within a preset time window from the synchronization signals of the target cell;

[0190] The search submodule is used to search within the target synchronization signal to obtain the downlink timing of the target cell.

[0191] In one example, the terminal-side cell synchronization device 700 also includes:

[0192] The acquisition module is also used to acquire the terminal coordinates and calculate the terminal's first timing advance based on the terminal coordinates, the ephemeris information and epoch time corresponding to the source cell;

[0193] The calculation module is also used to calculate the first transmission delay based on the common timing advance of the source cell and the first timing advance of the terminal;

[0194] The calculation module is also used to calculate the second timing advance of the terminal based on the terminal coordinates, the ephemeris information corresponding to the target cell, and the epoch time.

[0195] The calculation module is also used to calculate the second transmission delay based on the common timing advance of the target cell and the second timing advance of the terminal.

[0196] Figure 8A schematic diagram of the network equipment-side cell synchronization device provided in this application is shown. Figure 8 As shown, the network device-side cell synchronization device 800 provided in this application includes:

[0197] The first configuration module 801 is used to obtain a system information block from the received satellite signal and configure a reference point timing difference field in the system information block, so that the terminal obtains the reference point timing difference from the reference point timing difference field in the system information block based on the identifier of the target cell, and calculates the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0198] The second configuration module 802 is used to configure a reference point timing difference field in the radio resource control configuration information, so that the terminal can obtain the reference point timing difference from the reference point timing difference field in the radio resource control configuration information based on the identifier of the target cell, and calculate the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the start time of the terminal's source cell frame and the reference point timing difference.

[0199] In one example, the network device-side cell synchronization device 800 also includes:

[0200] The second configuration module is further configured to configure ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, so that the terminal can obtain the ephemeris information, epoch time, and common timing advance corresponding to the source cell and the target cell respectively from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information based on the source cell identifier and the target cell identifier, so that the terminal can calculate the first transmission delay and the second transmission delay based on the ephemeris information, epoch time, and common timing advance corresponding to the source cell and the target cell respectively, and calculate the downlink timing reference value of the target cell according to the first transmission delay, the second transmission delay, the terminal's source cell frame start time, and the reference point timing difference.

[0201] Figure 9 The cell synchronization system provided in this application is shown. The cell synchronization system 900 includes: a terminal 1000 and a network device 1100.

[0202] Figure 10 A schematic diagram of the hardware structure of the terminal provided in this application is shown. The terminal 1000 includes a terminal processor 1001 and a terminal memory 1002 storing computer program instructions.

[0203] Specifically, the processor 1001 of the aforementioned terminal may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0204] The terminal's memory 1002 may include mass storage for data or instructions. For example, and not limitingly, memory 1002 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. In one instance, memory 1002 may include removable or non-removable (or fixed) media, or the terminal's memory 1002 may be non-volatile solid-state memory.

[0205] In one instance, the terminal's memory 1002 may be a read-only memory (ROM). In one instance, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0206] The terminal's memory 1002 may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to one aspect of this application.

[0207] The terminal's processor 1001 implements the above by reading and executing computer program instructions stored in memory 1002. Figure 1 A cell synchronization method is shown in the embodiment.

[0208] In one example, the terminal may further include a communication interface 1003 and a bus 1004. Wherein, for example... Figure 10 As shown, the terminal's processor 1001, terminal's memory 1002, and terminal's communication interface 1003 are connected through the terminal's bus 1004 and complete communication between them.

[0209] The terminal's communication interface 1003 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0210] The terminal's bus 1004 includes hardware, software, or both, that couples components of the online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, the terminal's bus 1004 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0211] Figure 11 A schematic diagram of the hardware structure of the network device provided in this application is shown. The network device 1100 includes a network device processor 1101 and a network device memory 1102 storing computer program instructions.

[0212] Specifically, the processor 1101 of the aforementioned network device may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0213] The network device's memory 1102 may include mass storage for data or instructions. For example, and not limitingly, the network device's memory 1002 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. In one instance, the network device's memory 1002 may include removable or non-removable (or fixed) media, or the network device's memory 1102 may be non-volatile solid-state memory.

[0214] In one instance, the network device’s memory 1102 may be a read-only memory (ROM). In one instance, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0215] The memory 1102 of the network device may include read-only memory (ROM), random access memory (RAM), disk storage media device, optical storage media device, flash memory device, electrical, optical, or other physical / tangible memory storage device. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to one aspect of this application.

[0216] The processor 1101 of the network device implements the above by reading and executing computer program instructions stored in the memory 1102 of the network device. Figure 5 A cell synchronization method is shown in the embodiment.

[0217] In one example, the network device may further include a communication interface 1103 and a bus 1104. For example, Figure 11 As shown, the network device's processor 1101, network device's memory 1102, and network device's communication interface 1103 are connected through the network device's bus 1104 and complete mutual communication.

[0218] The communication interface 1103 of the network device is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0219] The network device's bus 1104 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated GraphicsPort (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, the network device's bus 1104 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, this application contemplates any suitable bus or interconnect.

[0220] Furthermore, in conjunction with one of the cell synchronization methods in the above embodiments, this application embodiment can provide a computer-readable storage medium for implementation. This computer-readable storage medium stores computer program instructions; when executed by a processor, these computer program instructions implement any of the cell synchronization methods in the above embodiments.

[0221] This application also provides a computer program product, including a computer program, which, when executed, implements any of the cell synchronization methods described in the above embodiments.

[0222] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0223] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, read-only memory (ROM), flash memory, erasable read-only memory (EROM), floppy disks, compact disc read-only memory (CD-ROM), optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0224] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0225] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0226] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and servers described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A cell synchronization method, applied to a terminal, characterized in that, include: In response to an event of switching from a source cell to a target cell, a reference point timing difference is obtained; wherein, the reference point timing difference is the timing deviation between the reference points of the source cell and the target cell; The downlink timing reference value of the target cell is calculated based on the first transmission delay, the second transmission delay, the start time of the source cell frame of the terminal, and the timing difference of the reference point; wherein, the first transmission delay is the delay of the signal from the reference point of the source cell to the terminal, and the second transmission delay is the delay of the signal from the reference point of the target cell to the terminal. If the signal quality of the source cell is greater than a preset signal quality threshold, then the downlink timing reference value is determined as the downlink timing of the target cell; If the signal quality of the source cell is less than or equal to the preset signal quality threshold, then the downlink timing reference value is used as the benchmark value, and the synchronization signal of the target cell is searched within the preset time window to obtain the downlink timing of the target cell.

2. The method according to claim 1, characterized in that, The process of obtaining the reference point timing difference includes: Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the system information block; wherein, the reference point timing difference field is obtained by the network device from the received satellite signals and configured in the system information block; And / or, Based on the identifier of the target cell, the reference point timing difference is obtained from the reference point timing difference field in the radio resource control configuration information; wherein, the reference point timing difference field is configured by the network device in the radio resource control configuration information.

3. The method according to claim 1, characterized in that, Before calculating the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the timing difference of the reference point, the method further includes: Based on the source cell identifier and the target cell identifier, the ephemeris information, epoch time, and common timing advance of the source cell and the target cell are obtained from the ephemeris information field, epoch time field, and common timing advance field in the radio resource control configuration information, respectively; wherein, the ephemeris information field, the epoch time field, and the common timing advance field are configured by the network device in the radio resource control configuration information.

4. The method according to claim 1, characterized in that, The step of calculating the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the timing difference of the reference point includes: in, This represents the downlink timing reference value; Indicates the start time of the source cell frame; This indicates the timing difference between the reference points; Indicates the second transmission delay; This indicates the first transmission delay.

5. The method according to claim 1, characterized in that, The step of using the downlink timing reference value as a base value to search for the synchronization signal of the target cell within a preset time window to obtain the downlink timing of the target cell includes: The maximum timing error is determined based on the signal quality of the source cell, wherein the maximum timing error is inversely proportional to the signal quality of the source cell; The preset time window is determined based on the downlink timing reference value and the maximum timing error; Select a target synchronization signal whose time falls within the preset time window from the synchronization signals of the target cell; The downlink timing of the target cell is obtained by searching within the target synchronization signal.

6. The method according to claim 1 or 3, characterized in that, Before calculating the downlink timing reference value of the target cell based on the first transmission delay, the second transmission delay, the source cell frame start time of the terminal, and the timing difference of the reference point, the method further includes: Obtain the terminal coordinates, and calculate the first timing advance of the terminal based on the terminal coordinates, the ephemeris information and epoch time corresponding to the source cell; The first transmission delay is calculated based on the common timing advance of the source cell and the first timing advance of the terminal. Based on the terminal coordinates, the ephemeris information and epoch time corresponding to the target cell, calculate the second timing advance of the terminal; The second transmission delay is calculated based on the common timing advance of the target cell and the second timing advance of the terminal.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement a cell synchronization method as described in any one of claims 1-6.

8. A computer program product, characterized in that, When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device performs a cell synchronization method as described in any one of claims 1-6.

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