A method and system for improving HDC network clock synchronization

Abstract

The application discloses a kind of promotion HDC network clock synchronization method and system, belong to power carrier communication technical field.By real-time acquisition of the signal-to-noise ratio of Beidou timing signal and the number of effective satellites, Beidou timing and local weighted NTB clock are dynamically weighted and fused, and the HDC network clock synchronization accuracy is improved from millisecond level to hundred microsecond level;At the same time, combined with the whole scene adaptive switching synchronization strategy and periodic maintenance mechanism of good, general and no signal of Beidou signal, it is ensured that stable synchronization is maintained when Beidou signal is unavailable, high-precision, high-robustness clock synchronization is realized, time slot conflict rate and network packet loss rate are significantly reduced, and the throughput and reliability of communication network are improved.

Description

Technical Field

[0001] This invention relates to the field of power line carrier communication technology, specifically to a method and system for improving HDC network clock synchronization. Background Technology

[0002] HDC (High-speed Dual-mode Communication) is a dual-mode communication technology based on a hybrid networking of HPLC (High-speed Power Line Carrier) and low-power wireless. It achieves data communication through a hybrid network of power lines and wireless channels. In an HDC communication network, the number of nodes can reach thousands. TDMA and CSMA / CA are usually required for time slot allocation to ensure the efficient operation of the network. Therefore, the clock synchronization accuracy between all nodes in the network is crucial.

[0003] Traditional HDC network clock synchronization primarily relies on the Network Time Base (NTB), achieved through a high-precision hardware clock module in the Central Coordinator (CCO) supplemented by latency compensation. However, existing solutions suffer from the following drawbacks:

[0004] 1) HDC network clock synchronization relies on the CCO local clock module, and all nodes in the network achieve synchronization through NTB time synchronization. With long-term network operation, the CCO local clock deviation will gradually accumulate due to factors such as crystal oscillator aging, temperature drift, and environmental changes, causing the synchronization accuracy of the entire network to continuously degrade over time;

[0005] 2) Power line carrier channels exhibit significant time-varying characteristics, with noise levels and impedance fluctuating dynamically with the power load in the distribution area. Traditional solutions use fixed parameters for delay compensation, failing to consider the impact of real-time changes in channel quality on transmission delay. When channel noise increases or load fluctuates significantly, the delay compensation error increases sharply, severely affecting synchronization accuracy.

[0006] 3) In HDC dual-mode networking, the channel environments of different nodes vary significantly, and some nodes may be located in areas with strong noise or weak signal coverage. Traditional solutions adopt a uniform synchronization strategy for all nodes, lacking the ability to differentiate based on the actual channel quality of each node. This leads to a significant degradation in the synchronization performance of some nodes in the network, thereby lowering the overall performance of the entire network. Summary of the Invention

[0007] To address the above three issues, the purpose of this invention is to propose a method and system for improving clock synchronization in HDC networks. By introducing dynamic weighted fusion of BeiDou time synchronization and local weighted NTB clocks, the problem of low clock synchronization accuracy and poor stability of large-scale nodes in HDC networks can be solved.

[0008] This was achieved through the following technical solutions:

[0009] A method for improving HDC network clock synchronization, characterized by the following steps:

[0010] Step S1: Hardware initialization, setting the initialization window length, window step size, and signal-to-noise ratio classification threshold;

[0011] Step S2: Acquire BeiDou timing signals in real time and calculate BeiDou timing error. The weighting coefficient α is related to the BeiDou clock correction; where the BeiDou timing signal includes the signal-to-noise ratio of the received signal and the number of effective satellites N;

[0012] Step S3: Collect the channel signal-to-noise ratio, construct a sliding window, determine the reliability level of the signal-to-noise ratio within the sliding window, and calculate the NTB clock correction weighting coefficient β;

[0013] Step S4: Normalize and correct the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β;

[0014] Step S5: Based on BeiDou timing error Adaptive switching clock synchronization strategy based on the number of effective satellites N;

[0015] Step S6: Perform latency compensation and clock synchronization between nodes, obtain the BeiDou timestamp and local NTB timestamp of the sending node and receiving node, calculate the total latency and correct the local NTB clock of the receiving node accordingly.

[0016] Step S7: Periodic maintenance, update the weight coefficient, delay compensation period and clock calibration period according to the preset period.

[0017] Optionally, hardware initialization includes: configuring a BeiDou dual-mode timing module for the Central Coordinator (CCO); and enabling a high-precision crystal oscillator NTB clock for the smart terminal (STA); wherein the high-precision crystal oscillator has a daily error of less than 0.5 s / d. This provides an external high-precision time reference for the entire network and maintains low clock drift even when there is no BeiDou signal.

[0018] Optionally, calculate the BeiDou timing error. The BeiDou timing error is calculated using the weighting coefficient α, the signal-to-noise ratio of the BeiDou timing received signal obtained in real time by the Central Coordinator (CCO), the effective number of satellites N, and a preset comprehensive correction coefficient K. Meanwhile, based on BeiDou timing error Calculate the BeiDou clock correction weight coefficient α, where the value of the BeiDou clock correction weight coefficient α ranges from 0 to 1.

[0019] Optionally, the channel signal-to-noise ratio (SNR) is collected in preset window steps and stored sequentially in a sliding window; the reliability of the SNR within the sliding window is classified into levels; and the number of sampling points for each SNR reliability level is weighted and averaged to obtain the NTB clock correction weight coefficient β. By weighting and averaging the number of sampling points for each SNR reliability level, the time-varying characteristics of the power line channel can be reflected in real time.

[0020] Optionally, based on the signal-to-noise ratio (SNR) grading threshold, the SNR reliability within the sliding window is classified into levels, including: high reliability, medium reliability, and low reliability.

[0021] Optionally, the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β are normalized, including making the sum of α and β equal to one. This ensures the consistency of weight allocation between BeiDou and NTB time synchronization during fusion, avoiding increased clock synchronization errors due to weight overflow or insufficient weight.

[0022] Optionally, the delay compensation and clock synchronization include: the transmitting node transmitting a data frame and recording a first BeiDou timestamp and a first local NTB timestamp; the receiving node recording a second BeiDou timestamp when receiving the data frame; and the receiving node recording a second local NTB timestamp when responding, calculating the total delay compensation and using the total delay compensation value to correct the local NTB clock of the receiving node.

[0023] Optionally, the adaptive switching of the clock synchronization strategy in step S5 includes: when the BeiDou timing error... When the error is less than the first threshold, BeiDou timekeeping is prioritized, with the BeiDou clock correction weighting coefficient α set to 1 and the NTB clock correction weighting coefficient β set to 0; when the BeiDou timekeeping error... When the value falls between the first and second thresholds, the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β are dynamically calculated according to step S4 and then weighted and fused. When the number of effective BeiDou satellites is lower than the preset number, the BeiDou clock correction weight coefficient α is forcibly set to 0 and the NTB clock correction weight coefficient β is set to 1, adopting a pure NTB clock synchronization mode. Based on the clock synchronization strategy, the optimal synchronization mode can be adaptively selected in all scenarios, including when the BeiDou signal is good, average, and no signal, achieving highly robust clock synchronization.

[0024] In addition, an improved HDC network clock synchronization system is proposed for implementing the above method, including: a central coordinator, multiple smart terminals (STAs), and a power line and low-power wireless hybrid communication bus between the central coordinator and the multiple smart terminals; wherein the central coordinator is equipped with a Beidou dual-mode timing module and a local NTB clock; and the STAs are equipped with a local NTB clock.

[0025] The beneficial effects of this invention compared to the prior art are:

[0026] 1) Introducing BeiDou time synchronization as an external high-precision time reference, and combining the signal-to-noise ratio and the number of effective satellites to quantitatively evaluate the BeiDou time synchronization error, thereby improving the clock synchronization accuracy of the HDC network from the millisecond level to the microsecond level;

[0027] 2) Through the hierarchical switching of the full-scenario adaptive clock synchronization strategy, intelligent coordination between BeiDou time synchronization and NTB time synchronization is achieved. It can work stably in all scenarios, including when BeiDou signal is good, average, or no BeiDou signal, overcoming the problem of lack of external means for calibration and adaptive control in existing technologies.

[0028] 3) By continuously monitoring the channel signal-to-noise ratio (SNR) based on a sliding window and performing graded weighting of SNR reliability, it can effectively adapt to the time-varying characteristics of the power line channel and reduce the impact of noise and composite fluctuations on synchronization accuracy. Attached Figure Description

[0029] Figure 1 A flowchart illustrating a method for improving HDC network clock synchronization;

[0030] Figure 2 This is an architecture diagram for improving HDC network clock synchronization systems;

[0031] Figure 3 This is a message interaction timing diagram for an improved method of HDC network clock synchronization. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figure 1 As shown in the figure, this is a flowchart of a method to improve HDC network clock synchronization, illustrating the complete processing flow of such a method. The specific steps of this method include the following:

[0034] Step S1: Hardware initialization, setting the initialization window length, window step, and signal-to-noise ratio (SNR) grading threshold. Specifically, hardware initialization includes configuring the BeiDou dual-mode timing module for the Central Coordinator (CCO); enabling a high-precision crystal oscillator (NTB) clock for the smart terminals (STAs). The BeiDou dual-mode timing module not only provides a time reference with a timing accuracy ≤100ns, providing a high-precision external unified time reference for the network, but also, for the STAs, uses a high-precision crystal oscillator (NTB) clock with a daily error of less than 0.5s / d to suppress local clock drift accumulation, ensuring that all nodes in the network maintain low clock drift even when there is no BeiDou signal or during synchronization intervals.

[0035] In this embodiment, the initial window length is set to 15 sampling data points; the step time is set to 1 minute; the signal-to-noise ratio (SNR) grading thresholds include a first grading threshold and a second grading threshold, which are set to 20 dB and 10 dB respectively. It should be noted that the first and second grading thresholds are existing industry application experience values. In practical applications, the thresholds need to be dynamically adjusted based on communication reliability.

[0036] Step S2: Acquire BeiDou timing signals in real time and calculate BeiDou timing error. The BeiDou clock correction weighting coefficient α is used. The BeiDou timing signal includes the signal-to-noise ratio (SNR) of the received signal and the number of effective satellites N. Specifically, based on the SNR and the number of effective satellites N of the BeiDou timing received signal obtained in real time by the Central Coordinator (CCO), and combined with a preset comprehensive correction coefficient K, the BeiDou timing error is calculated. It should be noted that the overall correction factor K is related to the receiver accuracy, geometric precision factor GDOP, and wavelength; in this embodiment, it is set to 10.

[0037] Meanwhile, based on BeiDou timing error Calculate the BeiDou clock correction weighting coefficient α= Where s is the exponential weighting coefficient, determined by fitting a large amount of field test data, and is taken as 3.25 in this embodiment; the BeiDou clock correction weighting coefficient α ranges from 0 to 1; when the BeiDou timing error The smaller the value, the closer α is to 1, which means that the BeiDou timing accuracy is higher and it plays a dominant role in subsequent weighted fusion; conversely, the closer α is to 0, the greater the weight of NTB timing.

[0038] Step S3: Collect the channel signal-to-noise ratio (SNR), construct a sliding window, determine the reliability level of the SNR within the sliding window, and calculate the NTB clock correction weighting coefficient β. Specifically, the operation steps include:

[0039] A sliding window is constructed based on a preset window length. The channel signal-to-noise ratio is collected according to the preset window step and stored in the sliding window in sequence. In this embodiment, the step time is set to one minute, that is, the channel signal-to-noise ratio is collected once every minute. After collection, it is stored in a sliding window of 15 points in sequence. After the channel signal-to-noise ratio of 15 sampling points is stored, a new channel signal-to-noise ratio is collected every minute while the earliest sampling point is removed.

[0040] The reliability level of the signal-to-noise ratio (SNR) within the sliding window is divided based on the SNR grading thresholds. These thresholds include a first grading threshold and a second grading threshold, and the reliability levels are high reliability, medium reliability, and low reliability. A high reliability is defined as an SNR greater than the first grading threshold; a medium reliability is defined as an SNR lower than the first grading threshold but higher than the second grading threshold; and a low reliability is defined as an SNR lower than the second grading threshold. In this embodiment, the first grading threshold is set to 20 dB, and the second grading threshold is set to 10 dB.

[0041] A hash table is constructed to count the number of sampling points for each signal-to-noise ratio (SNR) reliability level within a sliding time window. The number of high-reliability sampling points is denoted as n1, medium-reliability sampling points as n2, and low-reliability sampling points as n3. A weighted average is then applied to the sampling points for each SNR reliability level. Specifically, the number of high-reliability sampling points n1 is assigned a weight k1, the number of medium-reliability sampling points n2 is assigned a weight k2, and the number of low-reliability sampling points n3 is assigned a weight k3.

[0042] Because a higher signal-to-noise ratio (SNR) in a power line carrier channel results in lower delay jitter and higher NTB synchronization stability, a higher weight is assigned to the number of sampling points for high reliability. The weighting coefficients satisfy k1>k2>k3 and k1+k2+k3=1. The more high-reliability sampling points n1 there are, the more the channel is in a low-jitter state within the statistical period, and the higher the reference value of NTB clock synchronization. It should be noted that, regarding delay jitter, this embodiment of the invention performs boundary jitter reduction processing during sampling. Specifically, within a 2-second time range before and after sampling, 5 points are continuously sampled, and the effective number of points is averaged.

[0043] Next, the NTB clock correction weighting coefficient β is calculated. In this embodiment, k1 is set to 0.6, k2 to 0.3, and k3 to 0.1.

[0044] Step S4: Normalize the BeiDou clock correction weighting coefficient α and the NTB clock correction weighting coefficient β so that the sum of α and β is 1. Specifically, the normalization correction method prioritizes the BeiDou signal and supplements it with NTB, based on the timing error of the BeiDou signal. The BeiDou clock correction weight coefficient α is determined, and then β is adjusted to be the remaining weight that complements α. This ensures the consistency of weight allocation between BeiDou time service and NTB time service during fusion, and avoids increased clock synchronization error due to weight overflow or insufficient weight.

[0045] Step S5: Based on BeiDou timing error The clock synchronization strategy is adaptively switched according to the number of effective satellites N; specifically, the clock synchronization strategy is based on the BeiDou timing error. As a condition for switching clock synchronization strategies, when the BeiDou timing error... When the signal is below the first threshold, the BeiDou signal is considered good. At this time, BeiDou time synchronization is used as the primary method, and the BeiDou clock correction weight coefficient α is forcibly set to 1, while the NTB clock correction weight coefficient β is set to 0.

[0046] When BeiDou timing error When the signal is between the first threshold and the second threshold, the BeiDou signal is considered to be average. Based on step S4, the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β are dynamically calculated, and the BeiDou time synchronization and the NTB clock are weighted and fused. At this time, the robustness of clock synchronization reaches the highest level.

[0047] When the number of valid BeiDou satellites is lower than a preset number, it is determined that there is no BeiDou signal. The BeiDou clock correction weight coefficient α is forcibly set to 0, and the NTB clock correction weight coefficient β is set to 1, adopting a pure NTB clock synchronization mode. In this embodiment, the first threshold is set to 100μs; the second threshold is set to 500μs; and the number of valid BeiDou satellites is set to 4. When the number of acquired BeiDou satellites is less than 4, it is determined that there is no BeiDou signal, and NTB clock synchronization is forcibly adopted.

[0048] Step S6: Nodes perform latency compensation and clock synchronization, obtaining the BeiDou timestamps and local NTB timestamps of the sending and receiving nodes, calculating the total latency, and using this to correct the local NTB clock of the receiving node; specifically, the latency compensation and clock synchronization interaction process is as follows: Figure 3 As shown, the Central Coordinator (CCO) acts as the transmitting node to send data frames, recording the first BeiDou timestamp Tb1 and the first local NTB timestamp Tn1. When the receiving node of the smart terminal (STA) receives the data frame, it records the second BeiDou timestamp Tb2. The receiving node of the smart terminal generates a response message upon receiving the synchronization data frame, and records the second local NTB timestamp Tn11 in the response message. The smart terminal (STA) encapsulates the second BeiDou timestamp Tb2 and the second local NTB timestamp Tn11 in the data frame of the response message and sends it to the Central Coordinator (CCO).

[0049] The Central Coordinator (CCO) uses the BeiDou clock correction weighting coefficient α and the NTB clock correction weighting coefficient β, which have been normalized and corrected in step S4, to weight and fuse the absolute time deviation (difference between BeiDou timestamps) and the relative time drift (difference between NTB timestamps) to calculate the total delay compensation Δt. This total delay compensation value is then used to correct the local NTB clock of the smart terminal (STA) receiving node, completing the closed-loop synchronization. Specifically, the total delay compensation... The local NTB clock of the receiving node is corrected based on the total delay compensation.

[0050] Step S7: Periodic maintenance, update the weight coefficient, delay compensation period and clock calibration period according to the preset period.

[0051] In this embodiment, the update cycle for weight coefficients α and β is set to 1 minute. At each update time, step S2 is re-executed to acquire the BeiDou timing signal and calculate α, and step S3 is re-executed to determine the SNR reliability level within the sliding window and calculate β. After normalization correction in step S4, the latest weight coefficients are obtained. The calculation cycle for the delay compensation value is set to 5 seconds, meaning step S6 is executed every 5 seconds to calculate the total delay compensation value using the latest α and β and correct the local NTB clock of each node, ensuring real-time clock synchronization. The clock calibration cycle is 1 minute, synchronized with the weight update cycle, and the local NTB clock of each node is periodically calibrated to eliminate accumulated errors.

[0052] In addition, an improved HDC network clock synchronization system is proposed for implementing the above methods, such as... Figure 2 As shown, the system mainly consists of a central coordinator (CCO), multiple smart terminals (STA), and a power line and low-power wireless hybrid communication bus (HDC bus) connecting the central coordinator and the smart terminals. The central coordinator and each smart terminal node exchange data and transmit clock synchronization signals via the HDC bus, jointly constructing an HDC dual-mode communication network. The following is a detailed description of the system components and hardware connections:

[0053] The Central Coordinator (CCO) serves as the network's clock control center and high-precision time reference source. The CCO is equipped with a BeiDou dual-mode time synchronization module and a local NTB clock. The BeiDou dual-mode time synchronization module receives external satellite signals and calculates UTC time, providing an external high-precision time reference for network clock synchronization. The local NTB clock serves as the network time reference, dynamically weighted and fused with BeiDou signals to correct for accumulated deviations in the local time base.

[0054] Smart Terminal (STA): Configured with a local NTB clock, which is powered by a high-precision hardware crystal oscillator. During clock synchronization, the STA interacts with the Central Coordinator (CCO) to obtain and record the BeiDou timestamps and local NTB timestamps of the transmitting and receiving nodes.

[0055] Power Line and Low Power Wireless Hybrid Communication Bus (HDC Bus): Serving as the underlying dual-mode physical medium connecting the Central Coordinator (CCO) and each Smart Terminal (STA), it carries all service data streams and clock synchronization messages in the system. The HDC bus exhibits time-varying channel characteristics, and the system dynamically assesses the channel reliability level by sampling the channel signal-to-noise ratio of this bus using a sliding window.

[0056] During system operation, the Central Coordinator (CCO) adjusts the timing based on the BeiDou system's accuracy. The system dynamically calculates the BeiDou clock correction weighting coefficient α and the NTB clock correction weighting coefficient β based on the channel signal-to-noise ratio. Each smart terminal calculates the total delay compensation value Δt based on the received timestamp data, and uses this value to correct its own local NTB clock, thereby achieving clock synchronization among all nodes in the network.

[0057] In summary, this invention improves the clock synchronization accuracy of HDC networks from milliseconds to microseconds by introducing dynamic weighted fusion of BeiDou time synchronization and local NTB clock. Furthermore, by combining an adaptive switching synchronization strategy across all scenarios—good, average, and no BeiDou signal—it achieves high-precision and robust clock synchronization, significantly reducing time slot conflict rate and packet loss rate, and improving network throughput and reliability, demonstrating significant progress.

[0058] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A method for improving HDC network clock synchronization, characterized in that the steps include... include: Step S1: Hardware initialization, including: configuring the BeiDou dual-mode timing module for the Central Coordinator (CCO); enabling the high-precision crystal oscillator NTB clock for the smart terminal (STA); and setting the initialization window length, window step, and signal-to-noise ratio (SNR) grading threshold. Step S2: Acquire BeiDou timing signals in real time and calculate BeiDou timing error. The weighting factor α for BeiDou clock correction includes: the signal-to-noise ratio (SNR) of the BeiDou timing received signal obtained in real time by the Central Coordinator (CCO) and the number of effective satellites N, combined with a preset comprehensive correction factor K, to calculate the BeiDou timing error. Meanwhile, based on BeiDou timing error Calculate the BeiDou clock correction weighting coefficient α= s is the exponential weighting coefficient, and the BeiDou clock correction weighting coefficient α ranges from 0 to 1; Step S3: Collect the channel signal-to-noise ratio, construct a sliding window, determine the reliability level of the signal-to-noise ratio within the sliding window, and calculate the NTB clock correction weighting coefficient β; The reliability of the signal-to-noise ratio within the sliding window is classified into three levels: high reliability, medium reliability, and low reliability. Before calculating the NTB clock correction weighting coefficient β, a hash table is first constructed to count the number of sampling points for each signal-to-noise ratio reliability level within the sliding time window. The number of high reliability sampling points is recorded as n1, the number of medium reliability sampling points is recorded as n2, and the number of low reliability sampling points is recorded as n3. The sampling points of each signal-to-noise ratio reliability level are graded and weighted, and the number of high reliability sampling points n1 is assigned a weight k1, the number of medium reliability sampling points n2 is assigned a weight k2, and the number of low reliability sampling points n3 is assigned a weight k3. The weighted coefficients satisfy k1 > k2 > k3 and k1 + k2 + k3 = 1; Calculate the NTB clock correction weighting factor using the following formula. ; Step S4: Normalize and correct the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β; Step S5: Based on BeiDou timing error Adaptive switching clock synchronization strategy based on the number of effective satellites N; Step S6: Perform latency compensation and clock synchronization between nodes, obtain the BeiDou timestamp and local NTB timestamp of the sending node and receiving node, calculate the total latency and correct the local NTB clock of the receiving node accordingly. Step S7: Periodic maintenance, update the weight coefficient, delay compensation period and clock calibration period according to the preset period.

2. The method for improving HDC network clock synchronization according to claim 1, characterized in that, In step S1, the daily error of the high-precision crystal oscillator is less than 0.5 s / d.

3. The method for improving HDC network clock synchronization according to claim 1, characterized in that, Step S3 includes: collecting channel signal-to-noise ratios (SNRs) in preset window steps and storing them sequentially in a sliding window; classifying the reliability of the SNRs within the sliding window into different levels; and performing a weighted average of the number of sampling points for each SNR reliability level to obtain the NTB clock correction weight coefficient β.

4. The method for improving HDC network clock synchronization according to claim 1, characterized in that, In step S4, the normalization correction prioritizes the BeiDou timing signal, and the NTB supplementation logic normalizes and corrects the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β.

5. The method for improving HDC network clock synchronization according to claim 1, characterized in that, In step S6, the delay compensation and clock synchronization include: the sending node sends a data frame and records the first BeiDou timestamp and the first local NTB timestamp; the receiving node records the second BeiDou timestamp when receiving the data frame; when the receiving node responds, it records the second local NTB timestamp, calculates the total delay compensation, and uses the total delay compensation value to correct the local NTB clock of the receiving node.

6. The method for improving HDC network clock synchronization according to claim 1, characterized in that, Step S5 involves adaptively switching the clock synchronization strategy, including: when the BeiDou timing error... When the error is less than the first threshold, BeiDou timekeeping is prioritized, with the BeiDou clock correction weighting coefficient α set to 1 and the NTB clock correction weighting coefficient β set to 0; when the BeiDou timekeeping error... When the number of satellites is between the first threshold and the second threshold, the BeiDou clock correction weight coefficient α and the NTB clock correction weight coefficient β are dynamically calculated according to step S4 and then weighted and fused. When the number of effective BeiDou satellites is less than the preset number, the BeiDou clock correction weight coefficient α is forcibly set to 0 and the NTB clock correction weight coefficient β is set to 1, and the pure NTB clock synchronization mode is adopted.

7. A method for improving HDC network clock synchronization, used to implement any one of claims 1 to 6, characterized in that, include: Central coordinator, multiple smart terminals STA, and a power line and low-power wireless hybrid communication bus between the central coordinator and the multiple smart terminals; The central coordinator is equipped with a BeiDou dual-mode timing module and a local NTB clock; the STA is equipped with a local NTB clock.

Images