Clock synchronization deviation estimation method and apparatus, base station, and storage medium

Abstract

This application discloses a clock synchronization deviation estimation method, apparatus, base station, and storage medium, belonging to the field of communication technology. The method includes allocating fixed symbol resources within a predefined communication time slot for configuring probe reference signal resources; simultaneously allocating the probe reference signal resources to multiple remote radio frequency units (RF units) and terminals, enabling the RF units and terminals to transmit and receive probe reference signals in parallel within the same time slot; calculating the clock synchronization deviation value between RF units based on delay measurement data from each RF unit on the probe reference signal resources; and using the clock synchronization deviation value to compensate for the time difference measurement results of the probe reference signal transmitted by the terminal among the multiple RF units. This application ensures uninterrupted continuous transmission of communication services and achieves high-precision positioning measurements through dedicated resource allocation and a real-time deviation compensation mechanism.

Description

Technical Field

[0001] This application relates to the field of communication technology, specifically to a clock synchronization deviation estimation method, apparatus, base station, and storage medium. Background Technology

[0002] In distributed 5G base stations, achieving sub-meter accuracy (less than 1 meter) positioning relies on TDOA (Time Difference of Arrival) positioning technology. TDOA positioning requires extremely precise clock synchronization between each RRU (Radio Router Unit), with an error not exceeding ±8.138 nanoseconds (equivalent to a 2.4-meter positioning error). However, ordinary 5G communication services only require a synchronization accuracy of ±1.5 microseconds, making this requirement nearly 200 times more lenient. In actual operation, the RRU clock is affected by various factors, leading to deviations: temperature changes affect crystal oscillator accuracy, clock signals fluctuate randomly over time, and satellite signals or network clock sources may experience jumps. If these deviations are not corrected in time, the positioning system will simultaneously contain three types of errors: synchronization errors between devices; temperature-induced errors; and random jitter errors, ultimately resulting in a significant decrease in positioning accuracy, failing to meet sub-meter requirements. Summary of the Invention

[0003] This invention provides a clock synchronization deviation estimation method, device, base station, and storage medium, which can, while maintaining continuous transmission of 5G communication services, configure detection reference signal resources by dividing fixed symbol resources in predefined communication time slots, realize real-time calculation and compensation of clock synchronization deviation values ​​between multiple remote radio frequency units, and thus achieve sub-meter level measurement accuracy required for high-precision positioning.

[0004] Firstly, a method for estimating clock synchronization deviation is provided, including:

[0005] Fixed symbol resources are allocated in predefined communication time slots for configuring probe reference signal resources; The probe reference signal resources are simultaneously allocated to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot. The baseband unit calculates the clock synchronization deviation between the remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resource. The clock synchronization deviation value is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units.

[0006] Secondly, a clock synchronization deviation estimation device is also provided, comprising: The resource allocation module is used to allocate fixed symbol resources in predefined communication time slots for configuring probe reference signal resources; The resource allocation module is used to simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, so that the remote radio frequency units and the terminals can transmit and receive probe reference signals in parallel in the same time slot. The deviation calculation module is used to calculate the clock synchronization deviation value between the remote radio frequency units based on the time delay measurement data of each remote radio frequency unit on the probe reference signal resource; The deviation compensation module is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units using the clock synchronization deviation value.

[0007] Thirdly, a base station is also provided, comprising: The baseband unit is configured to allocate fixed symbol resources within a predefined communication time slot for configuring probe reference signal resources; simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot; calculate the clock synchronization deviation value between the remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resources; and use the clock synchronization deviation value to compensate for the arrival time difference measurement results of the probe reference signal transmitted by the terminal among the multiple remote radio frequency units. Fourthly, a computer-readable storage medium is also provided, on which a computer program is stored, which is loaded by a processor to perform the steps in any of the above-described methods or design schemes.

[0008] Beneficial effects: This application achieves high-precision clock synchronization under continuous 5G communication service transmission through the following technical solution: Fixed symbol resources are pre-allocated in the 5G standard communication time slots specifically for configuring probe reference signal resources. These fixed resources ensure the normal operation of conventional communication services and provide a dedicated channel for synchronization measurement. By simultaneously allocating probe reference signal resources to multiple remote radio frequency units and terminal devices, each remote radio frequency unit can complete the transmission and reception of probe reference signals in parallel with the terminal within the same time slot. Based on the time delay measurement data of the probe reference signals from each remote radio frequency unit, the precise clock synchronization deviation value between each remote radio frequency unit is calculated in real time. Finally, these calculated clock synchronization deviation values ​​are compensated in real time into the measurement results of the arrival time difference of the probe reference signals sent by the terminal between each remote radio frequency unit, thereby eliminating the impact of inter-device clock deviation on positioning accuracy and achieving sub-meter level high-precision positioning measurement. This application ensures uninterrupted continuous transmission of communication services and achieves high-precision positioning measurement through dedicated resource allocation and real-time deviation compensation mechanisms. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart illustrating a clock synchronization deviation estimation method provided in some embodiments of this application; Figure 2 This is one of the schematic diagrams of multiple RRUs transmitting and receiving SRS signals provided in some embodiments of this application; Figure 3 This is a second schematic diagram of multiple RRUs transmitting and receiving SRS signals provided in some embodiments of this application; Figure 4 This is the third of several schematic diagrams illustrating the transmission and reception of SRS signals by multiple RRUs provided in some embodiments of this application; Figure 5 This is the fourth of several schematic diagrams illustrating the transmission and reception of SRS signals by multiple RRUs provided in some embodiments of this application; Figure 6 This is the fifth of several schematic diagrams illustrating the transmission and reception of SRS signals by multiple RRUs provided in some embodiments of this application; Figure 7 This is one of the schematic diagrams illustrating the calculation of clock offset values ​​provided in some embodiments of this application; Figure 8 This is a second schematic diagram illustrating the calculation of clock offset values ​​provided in some embodiments of this application; Figure 9 This is a structural block diagram of a clock synchronization deviation estimation device provided in some embodiments of this application. Detailed Implementation

[0011] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0012] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0013] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0014] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0015] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0016] The following are the standardized definitions of the technical terms used in this application: Remote Radio Unit (RRU): A distributed radio frequency processing device in a 5G network, deployed at the remote end of the base station system to realize radio frequency signal transmission and reception functions, complete the mutual conversion between radio frequency signals and digital baseband signals, and perform the transmission and reception of probe reference signals.

[0017] Baseband Unit (BBU): The core control device of the base station system, responsible for physical layer baseband signal processing, protocol stack operation and system resource scheduling, and realizing centralized management and data processing of remote radio frequency units.

[0018] HUB (Host Unit): A signal relay device in a base station system, configured between the BBU and RRU, to realize the aggregation and distribution of multiple baseband signals, including signal combining, splitting and photoelectric conversion processing.

[0019] User Equipment (UE): Terminal access equipment for 5G networks, encompassing forms such as smartphones, industrial AGVs, and IoT terminals, serving as the target terminal for base station systems to provide communication and positioning services.

[0020] Sounding Reference Signal (SRS): A 5G physical layer-specific reference signal that is periodically sent by terminal equipment and used by the base station system for operations such as channel state measurement, delay estimation, and positioning parameter calculation.

[0021] Time Difference of Arrival (TDOA): A positioning algorithm based on multi-node collaborative measurement. It calculates the time difference between the arrival of the same signal at different remote radio frequency units and combines the spatial coordinates of the nodes to solve the terminal position.

[0022] In a distributed 5G base station system, multiple Remote Assisted Units (RRUs) work together to provide communication and positioning services. To achieve high-precision 5G positioning, the system employs the TDOA algorithm, whose positioning accuracy directly depends on the clock synchronization accuracy between RRUs. To achieve sub-meter (less than 1 meter) terminal positioning accuracy, the TDOA measurement error must be controlled within the nanosecond range (1 nanosecond is approximately equal to 30 centimeters). However, traditional 5G communication services only require a clock synchronization deviation between RRUs of less than ±1.5 microseconds (corresponding to a positioning error of ±450 meters), which is far from meeting the requirements for high-precision positioning. Although theoretically, the clock synchronization accuracy between RRUs can reach ±8.138 nanoseconds (corresponding to an error of ±2.4 meters), various dynamic deviations will be superimposed in actual operation: including temperature drift deviation caused by the temperature of the RRU crystal oscillator, random time jitter of the crystal oscillator itself, and system clock mutations caused by GNSS signal interruption or PTP transmission jitter. Without calibration, these accumulated deviations will far exceed the tolerance range of sub-meter positioning.

[0023] Existing clock synchronization deviation calibration methods mainly include the following two types of implementation schemes and their limitations: (1) Calibration method based on reference terminals. This method requires the pre-deployment of multiple dedicated reference terminal devices with precisely known locations in the target area, and the configuration of an independent power supply system and communication link for each reference terminal. This approach has significant deployment cost issues and is complex to implement, especially in large-scale commercial scenarios, where the deployment difficulty and maintenance costs will increase exponentially.

[0024] (2) RRU Polling-Based Calibration Method. This method utilizes RRU devices at known locations to sequentially simulate terminal transmission of probe reference signals and calculates the clock deviation between RRUs using a signal arrival time algorithm. This scheme has two main technical problems: 1) Subframe Configuration Switching Conflict Problem. Traditional methods require RRUs to switch operating modes when transmitting probe reference signals. Since RRUs, as base station devices, typically operate in downlink mode, while probe reference signals are uplink signals, this requires dynamic adjustment of symbol configuration in the radio frame. This mode switching not only interrupts normal communication but also causes timing alignment problems, making it impossible to perform communication services and positioning calibration simultaneously. 2) Historical Deviation Timeliness Problem. In actual deployment scenarios with a large number of RRUs, due to the long polling cycle, the clock deviation data used by the system is often historical measurement values. These historical data will gradually deviate due to the inherent characteristics of the device clock (such as temperature drift, random fluctuations, etc.), ultimately affecting positioning accuracy. Both of these traditional methods have obvious technical limitations and are difficult to meet the dual requirements of modern 5G networks for high-precision positioning and continuous communication.

[0025] This application achieves true parallel processing of communication and positioning through a time-slot resource configuration mechanism: within a predefined communication time slot, symbol resources are statically divided into three regions: the front region is fixed for regular communication service transmission, the middle region is configured with guard interval symbol resources, and the rear region is dedicated to the configuration of probe reference signal resources. By fixing the functional attributes of the symbols within the time slot, the remote radio unit does not need to change the subframe allocation configuration when transmitting probe reference signals, fundamentally solving the communication interruption problem caused by dynamic switching in traditional solutions. Each functional region strictly follows the preset symbol allocation strategy, ensuring that communication services and positioning measurements are executed in parallel throughout the entire process. Furthermore, the system can measure and compensate for clock deviations between RRUs in real time, including clock synchronization deviation, temperature drift deviation, random jitter deviation, and clock source transition deviation, ensuring that positioning accuracy remains at the sub-meter level. This design not only avoids communication interruption problems but also significantly reduces the requirements for RRU crystal oscillator accuracy, thereby reducing system costs.

[0026] On the one hand, this embodiment provides a clock synchronization deviation estimation method, such as Figure 1 As shown, it includes: S101: Allocate fixed symbol resources in the predefined communication time slots for configuring probe reference signal resources.

[0027] For example, the predefined communication time slot includes a structure consisting of a first part of symbols, a second part of symbols, and a third part of symbols, wherein the first part of symbols is allocated for communication services, the second part of symbols is set as a guard interval, and the third part of symbols is configured as the probe reference signal resource; wherein, when the remote radio unit transmits the probe reference signal, a predetermined timing advance is used to align the transmission timing with the downlink communication timing.

[0028] Understandably, a fixed partitioning strategy is adopted in the predefined communication time slots, predefining the time slot structure as a configuration mode consisting of three parts: the front part is fixed for downlink communication services, the middle part is set with guard interval symbols, and the rear part is dedicated to probe reference signal resources. This partitioning method is implemented through physical layer preconfiguration, without the need for dynamic adjustment of subframe ratios. Specifically, the front part maintains conventional 5G communication services, while the rear part supports remote radio unit calibration and terminal positioning functions simultaneously through frequency domain / code domain resource multiplexing, achieving physical isolation between communication and positioning services. The setting of guard interval symbols effectively avoids timing conflicts during signal transmission and reception. In addition, when the remote radio unit transmits the probe reference signal, a predetermined timing advance (e.g., 13μs) is used, so that the baseband IQ data of the probe reference signal generated by the baseband unit is transmitted with a predetermined time advance relative to the radio frame boundary, ensuring that the transmission timing of the probe reference signal of the remote radio unit is aligned with the downlink timing of the downlink communication service. For example, when simulating 5G terminal behavior, the SRS signal is sent 13μs in advance. At this time, the SRS baseband IQ data generated by the distributed 5G base station needs to be synchronized 13μs in advance, and the remote radio frequency unit can normally send and receive the detection reference signal and communication signal.

[0029] S102: Simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot.

[0030] For example, simultaneously allocating the detection reference signal resources to multiple remote radio units and terminals includes at least one of the following allocation methods: each remote radio unit and terminal occupies a different subcarrier group in the frequency domain of the third part of the symbol; each remote radio unit and terminal uses mutually orthogonal reference signal sequences in the third part of the symbol, the reference signal sequences being ZC sequences generated based on different root indices; each remote radio unit and terminal forms a spatially isolated directional transmission beam in the third part of the symbol through beamforming.

[0031] Understandably, this application can allocate the probe reference signal resources to multiple RRUs and terminals through three-dimensional isolation in the frequency domain, code domain, and spatial domain. For example, it can dynamically allocate the third part of the symbol resources (such as the last 9 symbols) to multiple RRUs and terminals, specifically as follows: The frequency band of the third part of the symbols (such as symbols 7-14) is divided according to the comb structure. For example, the RRU group occupies even-numbered subcarriers (such as Comb2: subcarriers 0, 2, 4, ...) for clock calibration; the terminal group occupies odd-numbered subcarriers (such as Comb4: subcarriers 1, 5, 9, ...) for positioning, so as to realize frequency domain orthogonal transmission.

[0032] Each device is assigned a unique ZC sequence (e.g., RRU1 uses root index 25, RRU2 uses 29), and mixed signals are separated by sequence orthogonality. Even if multiple RRUs share the same subcarrier group, the receiver can still distinguish the signals through correlation operations.

[0033] The spatial radiation direction of the SRS signal is controlled by an antenna array, and a time-division multiplexing mechanism is adopted: RRU1 transmits the SRS signal in a designated time slot, with the beam pointing to region A (azimuth angle 30°), while RRU2 / RRU3 / RRU4 turn off transmission and only receive signals; RRU2 transmits the SRS signal in the next time slot, with the beam pointing to region B (azimuth angle 150°), while RRU1 / RRU3 / RRU4 turn off transmission and only receive signals, and so on, to avoid co-channel interference.

[0034] In this way, the RRU and the terminal can synchronously send SRS signals (e.g., symbol 7 simultaneously transmits RRU calibration and terminal positioning signals) without polling or waiting. Clock skew (temperature drift, random jitter, etc.) is eliminated through three-dimensional isolation (frequency domain + code domain + spatial domain), stabilizing TDOA positioning errors at the sub-meter level. Physical isolation between communication symbols (the first 5 symbols) and SRS symbols (the last 9 symbols) ensures continuous operation of 5G services.

[0035] For example, simultaneously allocating the probe reference signal resources to multiple remote radio units and terminals includes: the remote radio unit transmitting the probe reference signal occupies the downlink symbols in the first part of the symbols; the remote radio unit or terminal receiving the probe reference signal occupies the uplink symbols in the third part of the symbols; when the same remote radio unit needs to switch between the first part of the symbols and the third part of the symbols, the second part of the symbols is used as a protection interval for the transmit / receive mode switching.

[0036] Understandably, the predefined communication time slots are divided into three parts: the downlink symbols in the front section (first part) are dedicated to communication; the uplink symbols in the back section (third part) are allocated to other RRUs for receiving or terminals for transmitting SRS signals; and the guard interval symbols (GAP) in the middle section (second part) are used to resolve timing conflicts during RRU transmit / receive mode switching. This structural design ensures that: communication symbols and positioning symbols are physically isolated, guaranteeing uninterrupted 5G services; multiple RRUs can simultaneously transmit and receive SRS signals; and the GAP interval in the back section avoids signal aliasing caused by instantaneous RRU switching.

[0037] S103: The baseband unit calculates the clock synchronization deviation between remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resource.

[0038] For example, the spatial propagation theoretical delay of the signal within the third part of the symbol is calculated based on the three-dimensional coordinates of each remote radio frequency unit, and this theoretical delay is superimposed on the synchronization deviation between devices, the time-varying deviation caused by temperature drift, the random jitter deviation of the crystal oscillator frequency, and the jump deviation of the system clock source.

[0039] Understandably, in a distributed antenna system, multiple RRUs need to be strictly synchronized to ensure coordinated signal transmission. First, the theoretical propagation delay of electromagnetic waves in space is calculated using the physical location coordinates (x, y, z) of each RRU (e.g., a 1μs delay for a distance of 300 meters). However, the actual synchronization clock deviation also includes four key types of deviations: ① inherent clock offsets caused by equipment manufacturing (e.g., sampling clock deviation), i.e., synchronization deviation; ② dynamic errors caused by crystal oscillator frequency drift due to temperature changes (e.g., approximately 0.1ppm per degree Celsius); ③ random jitter of the crystal oscillator itself (e.g., short-term stability of approximately 1e-11); ④ jump errors caused by sudden anomalies in the master clock source (e.g., GPS / PTP). The system obtains a synchronization compensation value with nanosecond-level accuracy by vector superimposing the theoretical spatial delay with these four types of deviations (formula: total clock synchronization deviation = theoretical delay + synchronization deviation + temperature drift time-varying deviation + random jitter + clock jump). For example, a certain RRU measures a total clock synchronization deviation of 20ns. This 20ns total clock synchronization deviation includes: spatial delay of 15ns, synchronization deviation of 3ns, temperature drift of 1.2ns, jitter of 0.5ns, and clock jump of 0.3ns. This process is completed in parallel with communication services without interrupting 5G data transmission.

[0040] S104: Use clock synchronization deviation value to compensate for the time difference measurement results of the arrival time of the probe reference signal sent by the terminal among multiple remote radio frequency units.

[0041] For example, the baseband unit compensates the clock synchronization deviation value calculated by the remote radio unit at the receiving end for the current third part of the symbol in real time into the arrival time difference measurement results of the current symbol and subsequent adjacent symbols.

[0042] For example, the communication time slot adopts a 14-symbol frame structure; wherein symbols 1 to 5 are used for downlink service transmission and carry the physical downlink shared channel, symbol 6 is specifically used as a guard interval for transmit / receive handover compensation, and symbols 7 to 14 are used for uplink probe reference signal transmission; wherein odd-numbered symbols 7, 9, 11, and 13 are allocated to the four remote radio units to transmit signals in turn, and symbols 7 to 14 are allocated to the terminal to transmit probe reference signals.

[0043] Understandably, through a real-time sliding compensation mechanism, the clock deviation value (synchronization deviation + temperature drift deviation + random jitter + system jump) calculated by the RRU in step S103 is injected into the TDOA calculation of the current symbol and adjacent symbols. Specifically, for example, after symbol 7 completes the inter-RRU clock deviation measurement, the clock deviation value is applied to the terminal positioning calculation of the current symbol 7 and subsequent symbol 8 (e.g., the time difference between the arrival of the terminal SRS of symbol 8 at RRU2 / 3 / 4), and hardware delay errors are eliminated through a preset feedforward compensation formula. This mechanism overcomes the lag of traditional historical data compensation, improving positioning accuracy, for example, from 2.4 meters to 0.8 meters, while maintaining continuous operation of communication services.

[0044] For example, assuming symbol 7 represents the time period during which RRU1 sends the SRS signal, RRU2 / RRU3 / RRU4 will receive the SRS signal and measure their respective clock deviation values. After receiving the signal, RRU2 / RRU3 / RRU4 will measure the clock deviation values ​​relative to RRU1 as follows: RRU2 measures a clock deviation of 5ns synchronization deviation + 3ns temperature drift + 2ns random jitter + 1ns system jump = 11ns; RRU3 measures a clock deviation of 9ns; and RRU4 measures a clock deviation of 13ns.

[0045] It should be noted that during the initial clock deviation measurement phase between RRUs, the total clock deviation value = theoretical spatial delay + synchronization deviation + temperature drift deviation + random jitter + system jump; during the terminal positioning compensation phase, the effective compensation value = synchronization deviation + temperature drift deviation + random jitter + system jump. Since the theoretical spatial delay has been eliminated through coordinate pre-compensation, only the dynamic deviation component needs to be processed at this time. That is, the dynamic deviation components (synchronization / temperature drift / jitter / jump) need to be updated in real time.

[0046] Symbol 7 represents the inter-RRU clock synchronization measurement slot. Its measurement results will update the compensation parameters in real time and be applied to the remaining time slot and subsequent SRS signal reception in Symbol 8. Symbol 8 represents the time slot when the terminal sends an SRS positioning signal. Each RRU processes the received signal based on the latest compensation value from Symbol 7, achieving real-time correction without historical data lag. For example, RRU2 measures an 11ns deviation in Symbol 7 and applies it immediately, correcting the reception delay in Symbol 8 from 50ns to 39ns (50ns - 11ns); RRU3 measures a 9ns deviation in Symbol 7 and applies it immediately, correcting the reception delay in Symbol 8 from 60ns to 51ns (60ns - 9ns); RRU4 performs the same real-time compensation mechanism.

[0047] TDOA positioning calculations are performed using compensated latency data. For example, the latency difference between RRU2 (39ns) and RRU3 (51ns) is 12ns (51ns-39ns), which translates to a physical distance difference of 3.6 meters (12ns × speed of light). This calculation, by subtracting the real-time clock deviation of each RRU (including synchronization error + temperature drift + random jitter), results in a final distance difference of 3.6 meters that reflects only the actual spatial relationship between the terminal and the two RRUs and is unrelated to hardware clock errors.

[0048] This real-time sliding compensation mechanism reduces the overall positioning error compared to traditional solutions (because traditional solutions do not compensate for temperature drift / synchronization errors in real time), while maintaining the continuity of communication services. It effectively solves the clock synchronization problem when multiple RRUs work together.

[0049] Please refer to Figure 2 , Figure 2 This application demonstrates the timing coordination mechanism of the RRU for SRS signal transmission and reception and downlink communication services within predefined communication time slots. For example, in a standard time slot (which can consist of 14 symbols) provided in this application, the first 6 symbols (1-6) are communication-related (e.g., D represents downlink, G represents guard interval), and the last 8 symbols (7-14) are specially allocated. It should be noted that the number of symbols in a standard time slot can be flexibly set by the 3GPP protocol, so this application is not limited to this.

[0050] For different RRUs (e.g., RRU1-RRU4), symbols 7-14 have different D (downlink), U (uplink), and G (guard interval) configurations, reflecting the functional division of different RRUs within that time slot. For example, RRU1 is configured as downlink (D) in symbol 7 for transmitting SRS, and as uplink (U) in symbols 10-14 for receiving signals, etc. The BBU is configured as U (uplink) in symbols 7-14, responsible for related baseband processing functions, etc. Details are as follows: (1) The first 6 symbols (1-6): For RRU1-RRU4 and BBU, the first 5 symbols (1-5) are all "D" (downlink), used for 5G downlink communication service data transmission; the 6th symbol is "G" (guard interval), which plays a buffering and protection role to prevent signal interference.

[0051] (2) The last 8 symbols (7-14): RRU1: Symbol 7 is "D" (continue downlink communication related operations), symbols 9-14 are "U" (uplink, which can be used for SRS related operations, etc.), and symbol 8 is "G" (guard interval).

[0052] RRU2: Symbols 7-8 are “U” (can be used for SRS-related operations, etc.), symbol 9 is “D” (downlink communication-related operations), symbols 11-14 are “U” (uplink, can be used for SRS-related operations, etc.), and symbol 10 is “G” (guard interval).

[0053] RRU3: Symbols 7-10 are “U” (can be used for SRS-related operations, etc.), symbol 11 is “D” (downlink communication-related operations), symbols 13-14 are “U” (uplink, can be used for SRS-related operations, etc.), and symbol 12 is “G” (guard interval).

[0054] RRU4: Symbols 7-12 are “U” (can be used for SRS related operations, etc.), symbol 13 is “D” (downlink communication related operations), and symbol 14 is “G” (guard interval).

[0055] BBU: Symbols 7-14 are all "U". 5G terminals can send sounding reference signals (SRS) on these symbols. The BBU is responsible for baseband processing and supports the RRU to complete SRS reception and measurement.

[0056] Figure 2 The label at the bottom center reads "SRS transmits IQ (in-phase and quadrature components, used to represent baseband signals) 13μs ahead," meaning that the SRS baseband IQ data generated by the baseband unit is 13 microseconds ahead of the air interface. It should be noted that the 13 microsecond difference can be flexibly set by the 3GPP protocol, so this application is not limited to this.

[0057] Taking RRU1 as an example: When it reaches symbols 9-14 "U" (uplink), because the IQ is 13μs ahead, RRU1 can receive the SRS signal in a timely and accurate manner when the timing corresponding to these symbols is reached (because the data is prepared in advance and meets the timing requirements for receiving the uplink SRS signal).

[0058] When the 7th "D" symbol (downlink) is executed, the baseband unit has already generated the downlink SRS IQ data 13μs in advance, so RRU1 can accurately send the SRS signal according to the downlink timing.

[0059] The same logic applies to other RRUs (such as RRU2-RRU4). During their respective "U" symbols (used for uplink-related operations such as SRS) and "D" symbols (for downlink communication-related operations), the timing of sending IQ via SRS 13μs in advance, along with the functional timing determined by their own symbol configuration, ensures: 1) SRS signal transmission: At appropriate uplink times such as the “U” symbol, the RRU sends an SRS reference signal using pre-prepared IQ data (e.g., simulating 5G terminal transmission for subsequent SRS-based operations such as positioning), and the transmission timing is aligned with the radio frame (meeting the overall system timing requirements).

[0060] 2) Downlink communication services: During downlink events such as the “D” symbol, communication service data is sent normally according to the downlink timing sequence and aligned with the radio frame (complying with the timing specifications for downlink data transmission in 5G communication systems).

[0061] Traditional solutions require adjustments to the subframe structure and timing conflicts with downlink communication services due to SRS-related operations (such as the terminal or RRU sending SRS signals during positioning), leading to communication interruptions or inaccurate SRS operations. However, this application addresses these issues by configuring symbols (clarifying the function of each RRU in different symbols, whether for downlink communication "D" or uplink SRS-related "U") and advancing the SRS transmission IQ by 13µs. This ensures that the RRUs, at the appropriate time corresponding to their symbol functions, can guarantee that downlink communication services and SRS signals are transmitted according to normal downlink timing (e.g., in the "D" symbol) and aligned with the radio frame, while also ensuring that SRS signals are received according to radio frame alignment requirements in appropriate symbols such as "U" (uplink-related timing). (Because the IQ is prepared in advance, it can be transmitted at the appropriate time, and the receiving end receives the uplink SRS signal and other communication service data 13µs in advance). This resolves the timing conflict between communication and SRS-based operations (such as potential positioning). Ultimately, this achieved the coordination between communication services (through downlink configuration such as the "D" symbol and normal downlink timing guarantees) and SRS-based related operations (through uplink configuration such as the "U" symbol and IQ to ensure timely transmission of SRS signals) within this time slot. This allows both to operate at their appropriate times and in accordance with system timing requirements (aligned with the radio frame). For example, communication services can continuously transmit data, while the SRS signal can be used for subsequent functions such as RRU inter-clock calibration and terminal positioning (SRS can be used for positioning calculations such as TDOA measurement).

[0062] As described above, the distributed 5G base station reserves the first 5 symbols of the predefined communication time slot for 5G communication and the last 9 symbols for SRS positioning. Positioning SRS resources can be allocated to several RRUs and 5G positioning terminals through combing and code division multiplexing. The transmission and reception of positioning SRS resources can be configured in the following ways: like Figures 3-6 As shown, Figures 3-6 The document demonstrates the configuration of special time slots in a distributed 5G base station and various forms of SRS (Sound Reference Signal) transmission and reception by different RRUs (RRU1, RRU2, RRU3, RRU4) within these time slots, as detailed below: The first 5 symbols (1-5) are reserved for 5G communication and are marked with "D" (representing downlink communication services).

[0063] The sixth symbol is "G" (guard interval), used for buffering to prevent signal interference between the first 5 communication symbols (downlink) and the last 9 positioning-related symbols (involving SRS transmission and reception, and uplink "U" operations, etc.).

[0064] The last 9 symbols (7-14) are reserved for SRS positioning. Among them, "D" indicates that the RRU is transmitting the SRS signal; "U" indicates that the RRU is receiving the SRS signal. When the same RRU switches from transmitting "D" to receiving "U", a "G" needs to be added in the middle (i.e., a guard interval, used for buffering during switching to prevent signal confusion).

[0065] The following is based on Figure 3 Let's take an example to illustrate: RRU1: In the first 6 symbols (1-6), 1-5 are "D" (downlink communication), and 6 is "G" (guard interval). In the last 9 symbols (7-14), 7 is "D" (transmitting SRS signal), 8 is "G" (guard interval for switching from transmitting "D" to receiving "U"), and 9-14 are "U" (receiving SRS signal).

[0066] RRU2: In the first 6 symbols (1-6), 1-5 are "D" and 6 is "G". In the last 9 symbols (7-14), 7-8 are "U" (receive SRS signal), 9 is "D" (transmit SRS signal), 10 is "G" (switch protection interval), and 11-14 are "U" (receive SRS reference signal).

[0067] RRU3: In the first 6 symbols (1-6), 1-5 are "D" and 6 is "G". In the last 9 symbols (7-14), 7-10 are "U" (receive SRS reference signal), 11 is "D" (transmit SRS signal), 12 is "G" (switch protection interval), and 13-14 are "U" (receive SRS signal).

[0068] RRU4: In the first 6 symbols (1-6), 1-5 are "D" and 6 is "G". In the last 9 symbols (7-14), 7-12 are "U" (receive SRS signal), 13 is "D" (transmit SRS signal), and 14 is "G" (switch protection interval).

[0069] BBU: In the first 6 symbols (1-6), 1-5 are "D" and 6 is "G". In the last 9 symbols (7-14), all are "U" (responsible for related baseband processing and other functions related to receiving SRS signals).

[0070] Therefore, Figures 3-6 The first six symbols (1-6) ensure communication (the first five "D" symbols are for downlink communication, and the sixth "G" symbol is for protection), while the last eight symbols (7-14) focus on SRS-related operations ("D" for transmitting, "U" for receiving SRS signals, and "G" for handover protection). The different positions of "D" (transmitting SRS), the range of "U" (receiving SRS), and the timing of adding "G" (handover protection) in symbols 7-14 for different RRUs reflect the division of labor in SRS transmission and reception among the RRUs configured before the distributed 5G base station begins operation (e.g., some RRUs transmit SRS signals first, while others transmit them later). However, they all collectively serve SRS-based system functions (such as positioning and clock calibration) while ensuring the normal operation of 5G communication services (the first six symbols). Strictly adhering to the rule of "RRU transmitting SRS signals as D, receiving as U, D to U plus G," the "G" symbol ensures the orderliness and signal quality of SRS signal transmission and reception (preventing interference during transmission and reception transitions), ensuring that the entire SRS-related operation meets the timing requirements of the wireless communication system within the time slot (alignment with the radio frame, etc.).

[0071] like Figure 7 As shown, Figure 7 The operating modes of RRU1-RRU4 and BBU on 14 symbols in a distributed 5G base station are shown below: Symbols 1-6: Symbols 1-5: RRU1-RRU4 and BBU are all "D" (downlink), used for 5G downlink communication data transmission to ensure the basic operation of communication services.

[0072] Symbol 6: RRU1-RRU4 and BBU are all "G" (guard interval), which serves as a buffer to prevent signal interference between the first 5 downlink communication symbols and subsequent SRS related symbols.

[0073] Symbol 7-14: Symbol 7: RRU1: "D" (Send SRS signal).

[0074] RRU2, RRU3, RRU4 and BBU: "U" (receive SRS signal).

[0075] At this point, symbols 7, 9, 11, and 13 represent RRU1, RRU2, RRU3, and RRU4 transmitting SRS signals, respectively. The other three RRUs receive the SRS signals for each symbol. Since the RRU locations are known, the time delay deviation can be calculated. For example, if RRU1 transmits an SRS signal, the other three RRUs (RRU2, RRU3, and RRU4) receive the signal. Since the RRU locations are known, the time delay deviation from RRU1 to the other RRUs can be calculated by receiving the signals (for example, after RRU2 receives the SRS signal transmitted by RRU1, it calculates the time delay deviation based on its own location, the location of RRU1, and the signal transmission time; similarly, RRU3 and RRU4 perform similar calculations).

[0076] Symbol 8: RRU1: "G" (guard interval, because after symbol 7 sends "D", if there is a subsequent receive operation U, "G" is added according to the rules).

[0077] RRU2, RRU3, RRU4 and BBU: "U" (receive SRS signal).

[0078] Simultaneously, the three RRUs receiving SRS signals will compensate the clock synchronization deviation value of the corresponding symbol 7 in real time to the 5G positioning terminal delay estimate of the corresponding symbol 7 and the adjacent symbol 8. At symbol 8, RRU2, RRU3, and RRU4, which previously received the SRS signal sent by RRU1 at symbol 7 (and calculated the delay deviation), will compensate the delay deviation calculated by symbol 7 in real time to the delay estimate of symbol 7 (its own delay estimate of receiving the RRU1 signal) and symbol 8 (the delay estimate of receiving the 5G positioning terminal signal), thereby improving the accuracy of the 5G positioning terminal delay estimate. For example, assuming symbol 7 calculates the clock synchronization deviation value Δt1 from RRU1 to RRU2, when symbol 8 receives the 5G positioning terminal signal, RRU2 will use Δt1 to correct the estimate of the terminal signal arrival time, making the estimate closer to the true value.

[0079] Symbol 9: RRU2: "D" (Send SRS signal).

[0080] RRU1, RRU3, RRU4 and BBU: "U" (receive SRS signal).

[0081] Similarly, in symbol 7, RRU2 sends an SRS signal, and the other three RRUs (RRU1, RRU3, and RRU4) receive and calculate the clock synchronization deviation value from RRU2 to themselves (e.g., RRU1 calculates the clock synchronization deviation value Δt2 after receiving the SRS signal sent by RRU2).

[0082] Symbol 10: RRU2: "G" (Guard interval, added after "D" is sent in symbol 9).

[0083] RRU1, RRU3, RRU4 and BBU: "U" (receive SRS signal).

[0084] RRU1, RRU3, and RRU4, which receive the SRS signal (symbol 9) sent by RRU2, compensate the clock synchronization deviation value (such as Δt2) calculated by symbol 9 in real time to symbol 9 (the estimated delay value of receiving the RRU2 signal) and symbol 10 (the estimated delay value of receiving the 5G positioning terminal signal).

[0085] Symbol 11: RRU3: "D" (Send SRS signal).

[0086] RRU1, RRU2, RRU4 and BBU: "U" (receive SRS signal).

[0087] RRU3 sends an SRS signal, and the other three RRUs (RRU1, RRU2, and RRU4) receive and calculate the time delay deviation from RRU3 to themselves (e.g., RRU1 calculates the clock synchronization deviation value Δt3 after receiving the SRS signal sent by RRU3).

[0088] Symbol 12: RRU3: "G" (Guard interval, added after symbol 11 sends "D").

[0089] RRU1, RRU2, RRU4 and BBU: "U" (receive SRS signal).

[0090] RRU1, RRU2, and RRU4, which receive the SRS signal (symbol 11) sent by RRU3, compensate the delay deviation (such as Δt3) calculated by symbol 11 in real time to symbol 11 (the estimated delay value of receiving the RRU3 signal) and symbol 12 (the estimated delay value of receiving the 5G positioning terminal signal).

[0091] Symbol 13: RRU4: "D" (Send SRS signal).

[0092] RRU1, RRU2, RRU3 and BBU: "U" (receive SRS signal).

[0093] RRU4 sends an SRS signal, and the other three RRUs (RRU1, RRU2, and RRU3) receive and calculate the clock synchronization deviation value from RRU4 to themselves (e.g., RRU1 calculates the clock synchronization deviation value Δt4 after receiving the SRS signal sent by RRU4).

[0094] Symbol 14: RRU4: "G" (Guard interval, added after symbol 13 sends "D").

[0095] RRU1, RRU2, RRU3 and BBU: "U" (receive SRS signal).

[0096] RRU1, RRU2, and RRU3, which receive the SRS signal (symbol 13) sent by RRU4, compensate the clock synchronization deviation value (such as Δt4) calculated by symbol 13 in real time to symbol 13 (the estimated delay value of receiving the RRU4 signal) and symbol 14 (the estimated delay value of receiving the 5G positioning terminal signal).

[0097] The role of BBU: BBU is "U" in symbols 7-14 (receive SRS signal). It is responsible for baseband processing of the SRS signals received by each RRU (such as demodulation and analysis of the received signal, assisting the RRU in completing the delay deviation calculation and subsequent compensation of the delay estimate of the 5G positioning terminal, or collecting the delay deviation information calculated by each RRU for higher-level processing, such as the overall system clock calibration and positioning calculation fusion).

[0098] Understandable. Figure 7 By configuring the “D” (transmit SRS), “U” (receive SRS), and “G” (guard interval) of RRU1-RRU4 and BBU on each symbol, the process of calculating the delay deviation based on SRS signals in a distributed 5G base station (through the transmission and reception of SRS signals between RRUs) and compensating for the delay estimate of the 5G positioning terminal (using the clock synchronization deviation value to correct the delay estimate of the received 5G positioning terminal signal) is demonstrated, reflecting the collaborative work between communication and SRS-based positioning-related operations.

[0099] In summary, this application achieves parallel processing of communication services and high-precision positioning by intelligently allocating fixed symbol resources (such as symbols 7-14) within 5G communication time slots for SRS reference signal transmission and reception. Specifically, the last 9 symbols of a predefined communication time slot are reserved for SRS positioning, while the first 5 symbols maintain communication services. Through combing / code division multiplexing, the RRU and the terminal can transmit and receive SRS in parallel within the same time slot, avoiding service interruptions caused by subframe switching. The delay data (including synchronization deviation, temperature drift, random jitter, and system jump) measured by the RRU in dedicated symbols (such as symbol 7) is used to correct the terminal TDOA measurement values ​​of adjacent symbols (such as symbol 8) in real time. Symbol-level real-time calibration eliminates historical value deviations (temperature drift / jitter / jump), reducing the dependence on the RRU crystal oscillator accuracy, allowing ordinary commercial-grade hardware to meet sub-meter positioning requirements.

[0100] like Figure 8 As shown, Figure 8 This demonstrates how RRU1 and UE transmit SRS signals, and how RRU2, RRU3, and RRU4 are selected for delay estimation. The formula derivation is as follows: : ; : ; : ; : ; : indicates the first RRU receives and the first The clock synchronization deviation transmitted by the RRU or a certain UE can be rewritten as ; : indicates that the j-th RRU or a certain UE sends the j-th transmission. During RRU reception, the clock deviation caused by temperature changes in components such as the RRU crystal oscillator is... The RRU crystal oscillator generates random clock deviations due to time jitter. Clock source jitter causes clock transition deviation in distributed 5G base station systems to be: The sum of ; Indicates the first RRU receives and the first The delay is estimated based on the actual location of the RRU or a specific UE, and the theoretical delay is calculated based on the theoretical location.

[0101] ; = .

[0102] RRU1 transmits the SRS signal, and RRU2, RRU3, and RRU4 receive the signal and perform time delay deviation estimation. ; ; .

[0103] The UE transmits the SRS signal, and RRU2, RRU3, and RRU4 receive the signal to perform delay offset estimation. ; ; .

[0104] The corrected latency is:

[0105]

[0106]

[0107] The TDOA algorithm calculates the UE's latency difference. If it's real-time latency deviation compensation, regardless of whether the RRU or the UE sends the SRS reference signal, the receiving RRU hardware is unaware of this. Therefore, the physical characteristics are consistent within the same time slot or symbol, meaning there is... The clock synchronization deviation between RRUs within the same time slot or symbol is fixed and is independent of whether it is an RRU or a UE transmitter. :

[0108]

[0109] If historical delay offset compensation is used, the historical random clock offset and the current actual clock offset may not be consistent. Historical clock synchronization deviations and current clock deviations may not be consistent. .

[0110]

[0111]

[0112]

[0113]

[0114] On the other hand, such as Figure 9 As shown, this embodiment provides a clock synchronization deviation estimation device, including a resource partitioning module 901, a resource allocation module 902, a deviation calculation module 903, and a deviation compensation module 904.

[0115] For example, the resource allocation module 901 is used to allocate fixed symbol resources in a predefined communication time slot for configuring probe reference signal resources.

[0116] For example, the resource allocation module 902 is used to simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, so that the remote radio frequency units and the terminals can transmit and receive probe reference signals in parallel in the same time slot.

[0117] For example, the deviation calculation module 903 is used to calculate the clock synchronization deviation value between the remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resource estimated by the baseband unit.

[0118] For example, the deviation compensation module 904 is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units using the clock synchronization deviation value.

[0119] Understandably, this embodiment dynamically allocates fixed symbol resources in the 5G communication time slot (e.g., symbol 7 is configured as a probe reference signal resource), enabling multiple remote radio units and terminals to transmit and receive probe reference signals in parallel within the same time slot. The resource allocation module 902 ensures that service data transmission and SRS measurement are time-division multiplexed without interruption. The deviation calculation module 903 baseband unit calculates the clock synchronization deviation in real time based on the delay measurement data of each RRU on the dedicated symbol (e.g., 11ns measured by RRU2 includes temperature drift / synchronization error). The deviation compensation module 904 immediately applies the calculation result to the terminal signal arrival time compensation of subsequent symbols (e.g., symbol 8). Through this symbol-level closed-loop processing, while maintaining the continuity of 5G services, the delay measurement error of multi-RRU collaborative positioning is reduced, achieving the pure delay difference measurement required for sub-meter positioning accuracy.

[0120] This embodiment also provides a base station, including a baseband unit and multiple remote radio frequency units: The baseband unit is configured to allocate fixed symbol resources in a predefined communication time slot for configuring probe reference signal resources; simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot; calculate the clock synchronization deviation value between remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resources; and use the clock synchronization deviation value to compensate for the arrival time difference measurement results of the probe reference signal transmitted by the terminal among multiple remote radio frequency units.

[0121] Understandably, in this embodiment, the baseband unit intelligently allocates fixed symbol resources (such as symbol 7) in the 5G communication time slot for dedicated detection reference signal configuration. The resource allocation module enables multiple remote radio units and terminals to complete SRS transmission and reception in parallel within the same time slot, achieving seamless time-division multiplexing of communication services and measurement signals. Each RRU calculates the clock synchronization deviation value in real time based on the delay data measured by the dedicated symbol (such as 11ns measured by RRU2 including crystal oscillator temperature drift / synchronization error). The baseband unit centrally processes and feeds back compensation parameters, and immediately performs dynamic correction on the arrival time difference of the terminal signal in the next symbol period (such as symbol 8). This symbol-level real-time closed-loop compensation mechanism reduces the delay error of multi-RRU collaborative positioning, ensuring continuous transmission of 5G services while achieving sub-meter positioning accuracy for TDOA.

[0122] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to execute the arrangement in any of the methods described above.

[0123] In the embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0124] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0125] The present application provides a clock synchronization deviation estimation method, apparatus, base station, and storage medium. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present application. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present application. Therefore, the content of this specification should not be construed as a limitation of the present application.

Claims

1. A method for estimating clock synchronization deviation, characterized in that, include: Fixed symbol resources are allocated in predefined communication time slots for configuring probe reference signal resources; The probe reference signal resources are simultaneously allocated to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot. The baseband unit calculates the clock synchronization deviation between the remote radio frequency units based on the delay measurement data of each remote radio frequency unit on the probe reference signal resource. The clock synchronization deviation value is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units.

2. The clock synchronization deviation estimation method according to claim 1, characterized in that, The predefined communication time slot includes a structure consisting of a first part of symbols, a second part of symbols, and a third part of symbols, wherein the first part of symbols is allocated for communication services, the second part of symbols is set as a guard interval, and the third part of symbols is configured as the probe reference signal resource.

3. The clock synchronization deviation estimation method according to claim 2, characterized in that, The simultaneous allocation of the detection reference signal resources to multiple remote radio frequency units and terminals includes at least one of the following allocation methods: Each remote radio frequency unit and the terminal occupy different subcarrier groups in the frequency domain of the third part of the symbol; Each remote radio frequency unit and the terminal respectively adopt mutually orthogonal reference signal sequences on the third part of the symbol; Each remote radio frequency unit and the terminal form a spatially isolated directional transmission beam on the third part of the symbol through beamforming.

4. The clock synchronization deviation estimation method according to claim 2, characterized in that, The step of simultaneously allocating the detection reference signal resources to multiple remote radio frequency units and terminals includes: The remote radio unit that transmits the probe reference signal occupies the downlink symbol in the third part of the symbol; the remote radio unit or terminal that receives the probe reference signal occupies the uplink symbol in the third part of the symbol; when the same remote radio unit needs to switch between downlink and uplink, the second part of the symbol is used as a protection interval for the transmit / receive mode switching. Among them, when the remote radio frequency unit transmits the detection reference signal, it adopts a predetermined timing advance to align the transmission timing with the downlink communication timing.

5. The clock synchronization deviation estimation method according to claim 2, characterized in that, The steps for calculating the clock synchronization deviation value include: The theoretical spatial propagation delay of the signal within the third part of the symbol is calculated based on the three-dimensional coordinates of each remote radio frequency unit. This theoretical delay is then superimposed on the synchronization deviation between devices, the time-varying deviation caused by temperature drift, the random jitter deviation of the crystal oscillator frequency, and the jump deviation of the system clock source.

6. The clock synchronization deviation estimation method according to claim 1, characterized in that, The compensation for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units using the clock synchronization deviation value includes: The remote radio frequency unit at the receiving end compensates the clock synchronization deviation value calculated for the current third symbol in real time into the arrival time difference measurement results of the current symbol and subsequent adjacent symbols.

7. The clock synchronization deviation estimation method according to claim 2, characterized in that, The communication time slot adopts a 14-symbol frame structure; wherein, the first part of the symbols includes symbols 1 to 5, which are used for downlink service transmission and carry the physical downlink shared channel; the second part of the symbols includes symbol 6, which is specifically used as a guard interval for communication transmission and uplink sounding reference signal switching compensation; symbols 7 to 14 are used for uplink sounding reference signal transmission; wherein odd-numbered symbols 7, 9, 11, and 13 are allocated to the four remote radio units to transmit signals in turn, and symbols 7 to 14 are allocated to the terminal to transmit sounding reference signals.

8. A clock synchronization deviation estimation device, characterized in that, include: The resource allocation module is used to allocate fixed symbol resources in predefined communication time slots for configuring probe reference signal resources; The resource allocation module is used to simultaneously allocate the probe reference signal resources to multiple remote radio frequency units and terminals, so that the remote radio frequency units and the terminals can transmit and receive probe reference signals in parallel in the same time slot. The deviation calculation module is used to calculate the clock synchronization deviation value between the remote radio frequency units based on the time delay measurement data of each remote radio frequency unit on the probe reference signal resource; The deviation compensation module is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units using the clock synchronization deviation value.

9. A base station, characterized in that, include: The baseband unit is configured to allocate fixed symbol resources in a predefined communication time slot for configuring probe reference signal resources; The probe reference signal resources are simultaneously allocated to multiple remote radio frequency units and terminals, enabling the remote radio frequency units and terminals to transmit and receive probe reference signals in parallel within the same time slot. Based on the time delay measurement data of each remote radio unit on the probe reference signal resource, calculate the clock synchronization deviation value between the remote radio units; The clock synchronization deviation value is used to compensate for the time difference measurement results of the probe reference signal sent by the terminal among multiple remote radio frequency units.

10. A computer-readable storage medium, characterized in that, It stores a computer program, which is loaded by a processor to perform the steps in the clock synchronization deviation estimation method according to any one of claims 1-7.

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