A Dual-Mode Communication Method of HPLC and Micro-Power Wireless

Abstract

The present invention provides an HPLC and micro-power wireless dual-mode communication method, belonging to the technical field of multiplex communication, for realizing the coordinated transmission of power line carrier communication and micro-power wireless communication, including a modulation-end method and a demodulation-end method; the modulation end includes: First, collect HPLC and micro-power wireless signals, and perform band-pass filtering and spectrum sensing to obtain non-interfering frequency bands. Then, establish a unified time reference, calculate the transmission delay, and perform delay compensation. Next, use orthogonal frequency division multiplexing technology for modulation and transmission. At the receiving end, select the primary and backup channels according to the signal strength, and use adaptive modulation and demodulation technology for demodulation and data recovery. This solution makes full use of the advantages of HPLC and micro-power wireless, realizes the integration of the two communication technologies, and solves the technical problem that currently, HPLC and micro-power wireless communication often use independent communication carriers and transmission protocols and it is difficult to achieve effective coordination.

Description

Technical Field

[0001] The present invention belongs to the technical field of multiplex communication, and more specifically, relates to an HPLC and micro-power wireless dual-mode communication method. Background Art

[0002] Currently, smart grid and Internet of Things technologies are developing rapidly. Among them, power line carrier communication (HPLC) and micro-power wireless communication are becoming important communication technologies. HPLC uses the existing power lines as communication media to achieve data transmission on the power lines and is widely used in fields such as grid automation and smart home. Micro-power wireless communication uses radio electromagnetic waves to achieve long-distance wireless connections and is applied to scenarios such as industrial control and Internet of Things sensing. The two communication technologies have their own characteristics. HPLC has the advantages of wide coverage and low cost, while micro-power wireless has the characteristics of strong flexibility and strong anti-interference ability.

[0003] In many application scenarios, HPLC and micro-power wireless communication need to work together to give full play to their respective advantages. For example, in the smart grid, HPLC can be used for data backhaul on the main lines, while micro-power wireless can be used for device connection in the last mile; in factory automation, HPLC is responsible for device networking on the production line, and micro-power wireless is used for flexible connection of mobile devices. However, currently, HPLC and micro-power wireless communication often use independent communication carriers and transmission protocols, making it difficult to achieve effective coordination.

[0004] The main problems are as follows:

[0005] 1. Low utilization efficiency of spectrum resources. The two communication systems each occupy different frequency bands, making it difficult to perform spectrum multiplexing and resulting in waste of spectrum resources.

[0006] 2. Communication performance is easily interfered. Due to frequency band isolation, HPLC and micro-power wireless communication are easily interfered with each other, affecting communication quality.

[0007] 3. System delay is difficult to coordinate. Due to different transmission mechanisms of HPLC and micro-power wireless, it is difficult to achieve time synchronization, resulting in too large an end-to-end delay difference.

[0008] Therefore, there is an urgent need for a new technical solution to achieve coordinated transmission of HPLC and micro-power wireless communication, improve spectrum utilization efficiency, and enhance communication reliability. Summary of the Invention

[0009] In view of this, the present invention provides an HPLC and micro-power wireless dual-mode communication method, which can solve the technical problem that currently, HPLC and micro-power wireless communication often use independent communication carriers and transmission protocols and it is difficult to achieve effective coordination.

[0010] The present invention is implemented as follows:

[0011] The present invention provides an HPLC and micro-power wireless dual-mode communication method for realizing the collaborative transmission of power line carrier communication and micro-power wireless communication, including a modulation-end method and a demodulation-end method;

[0012] The modulation-end method includes the following steps:

[0013] S11. Collect the HPLC signal and the micro-power wireless signal, and perform band-pass filtering on the HPLC signal; specifically: First, collect two electrical signals transmitted by the HPLC device and the micro-power wireless device. Then, use a band-pass filter to filter the HPLC signal to remove high-frequency and low-frequency interference components in the signal and retain the effective signal frequency band. The purpose of this step is to separate and obtain the two communication signals and prepare for subsequent orthogonal frequency division multiplexing.

[0014] S12. Control the orthogonal frequency division multiplexing modulation and demodulation platform to map the HPLC signal to the first carrier frequency band of the orthogonal frequency division multiplexing modulation and demodulation platform, and map the micro-power wireless signal to the second carrier frequency band of the orthogonal frequency division multiplexing modulation and demodulation platform; specifically: First, set the parameters of the orthogonal frequency division multiplexing (OFDM) modulation and demodulation platform, including the number of subcarriers, carrier spacing, symbol period, etc. Then, modulate the processed HPLC signal to the first carrier frequency band of the platform, specifically set at 3 kHz to 500 kHz; modulate the micro-power wireless signal to the second carrier frequency band, specifically set at 470 MHz to 510 MHz. The purpose of this is to achieve frequency reuse of the two communication signals and improve the spectrum utilization efficiency.

[0015] S13. Perform channel scanning on the first carrier frequency band and the second carrier frequency band based on spectrum sensing technology to obtain the spectrum occupancy information of the HPLC channel and the micro-power wireless channel; specifically: First, use a spectrum analyzer to perform a 60-second spectrum scan in the frequency band of 3 kHz to 510 MHz and record the spectrum occupancy. Then, analyze the spectrum occupancy status of the HPLC channel and the micro-power wireless signal on each subcarrier according to the scan results to obtain the spectrum distribution of the two signals in the time-frequency domain. The purpose of this step is to obtain the spectrum resource allocation of the current channel environment and provide a basis for subsequent dynamic resource management.

[0016] S14. Adopt a dynamic spectrum resource allocation model to allocate non-interfering frequency bands for HPLC communication and micro-power wireless communication according to the spectrum occupancy information; the purpose of this step is to adjust the allocation of the two signals in the frequency domain in real time according to the current channel conditions and improve the spectrum utilization efficiency.

[0017] S15. Establish a unified time reference using time-sensitive network technology to generate a time synchronization signal. Specifically: deploy precision clock synchronization devices at the modulation end and the demodulation end, and use time-sensitive network technology to establish a unified time reference at both ends. Then generate a time synchronization signal based on the time reference to provide a basis for subsequent delay compensation. The purpose of this step is to ensure time synchronization between HPLC and micro-power wireless communication, laying a foundation for the delay compensation of the two signals.

[0018] S16. Calculate the transmission delays of HPLC communication and micro-power wireless communication according to the time synchronization signal. Specifically: use the established time reference to measure the transmission time difference of HPLC and micro-power wireless signals from the transmitting end to the receiving end to obtain the actual transmission delays of the two signals. The purpose of this step is to obtain the delay parameters of the two communication signals in the system as the input for delay compensation.

[0019] S17. Input the transmission delay into the delay compensation equation to output the delay compensation coefficient and phase correction parameter for delay compensation of the data transmission of HPLC communication and micro-power wireless communication.

[0020] S18. Perform orthogonal frequency division multiplexing modulation on the HPLC signal and the micro-power wireless signal according to the delay compensation coefficient and phase correction parameter, and send the modulated signal through the channel. Specifically: apply the delay compensation coefficient and phase correction parameter calculated in step S17 to the OFDM modulation process of the HPLC and micro-power wireless signals. The two modulated signals are transmitted through the power line and the wireless channel. The purpose of this step is to achieve frequency division multiplexing transmission of the HPLC and micro-power wireless signals, suppress the interference caused by the delay difference, and ensure high-quality transmission of the two signals.

[0021] The method at the demodulation end includes the following steps:

[0022] S21. Receive the HPLC signal and the micro-power wireless signal after delay compensation and perform signal strength measurement. Specifically: first, the receiving end obtains the HPLC and micro-power wireless signals from the power line and the wireless channel. Then, use a power detection circuit to measure and record the received power of the two signals. The purpose of this step is to obtain the current signal quality information as the basis for subsequent adaptive modulation and demodulation.

[0023] S22. Select the communication channel with better signal quality as the main channel and the other channel as the backup channel according to the signal strength measurement result. Specifically: according to the measurement result of step S21, compare the received powers of the HPLC channel and the micro-power wireless channel, and select the one with better signal quality as the main channel and the other as the backup channel. The purpose of this step is to achieve adaptive switching of the communication link and ensure reliable data transmission of the system in a complex channel environment.

[0024] S23. Demodulate the signal of the main channel using an adaptive modulation and demodulation method. When the signal quality of the main channel is lower than a preset threshold, switch to the backup channel. Specifically: First, demodulate the signal of the main channel using an adaptive OFDM demodulation algorithm. At the same time, continuously monitor the signal quality of the main channel. When the quality index (such as signal-to-noise ratio, bit error rate, etc.) is lower than the preset threshold Q th = 15 dB, automatically switch to the backup channel for demodulation. The purpose of this step is to dynamically select the best demodulation path according to the current channel state and improve the reliability of communication.

[0025] S24. Perform channel decoding and data recovery on the demodulated data to complete the reception of dual-mode communication data. Specifically: First, perform channel encoding and decoding on the demodulated digital signal to remove the errors introduced by the channel. Then, perform data recovery on the decoded bit stream to obtain the final HPLC and micro-power wireless communication data. The purpose of this step is to complete the end-to-end reception of dual-mode communication and provide reliable data services for upper-layer applications.

[0026] Preferably, the first carrier frequency band is specifically 3 KHz to 500 KHz, and the second carrier frequency band is specifically 470 MHz to 510 MHz.

[0027] Based on the above technical solutions, a HPLC and micro-power wireless dual-mode communication method of the present invention can also be improved as follows:

[0028] Among them, the dynamic spectrum resource allocation model includes a channel capacity matrix equation, a power allocation matrix equation, a spectrum efficiency matrix equation, and a fusion allocation network.

[0029] Further, the channel capacity matrix equation is used to calculate the potential data transmission capabilities of the HPLC and micro-power wireless channels. The inputs are channel bandwidth, transmit power, channel gain, noise power spectral density, and interference power, and the outputs are the channel capacity values and capacity change trends of each sub-channel.

[0030] Further, the power allocation matrix equation is used to allocate the optimal transmit power to each sub-channel according to the channel state. The inputs are channel response, noise power, phase angle, and the number of sub-channels, and the output is the optimal power allocation scheme that satisfies the total power constraint.

[0031] Further, the spectrum efficiency matrix equation is used to evaluate the utilization efficiency of spectrum resources. The inputs are sub-carrier data rate, bandwidth, bit error rate, and frequency information, and the outputs are the overall spectrum efficiency and efficiency gradient of the system.

[0032] Furthermore, the fusion allocation network adopts a lightweight neural network, which is used to synthesize the output results of three matrix equations and make intelligent decisions. The input is the channel capacity values, power allocation schemes, and spectral efficiencies of the three equations, and the output is the optimal frequency band allocation scheme for the HPLC and micro-power wireless channels. The specific structure is as follows: the input layer contains 15 neurons, the two hidden layers contain 8 and 4 neurons respectively, and the output layer contains 2 neurons. The ReLU activation function and Dropout regularization are used.

[0033] Furthermore, the steps for establishing the training dataset of the fusion allocation network are specifically as follows:

[0034] Collect HPLC communication data under different power line channel environments;

[0035] Collect micro-power wireless communication data at different spatial locations;

[0036] Calculate the channel capacity, optimal power allocation, and spectral efficiency corresponding to each group of data;

[0037] Record the actually used frequency band allocation scheme and its communication performance;

[0038] Use the communication performance as a label to construct the training dataset.

[0039] The steps for training the fusion allocation network are specifically as follows:

[0040] 1. Normalize the training data;

[0041] 2. Adopt the mini-batch stochastic gradient descent algorithm;

[0042] 3. Select the mean squared error as the loss function;

[0043] 4. Set the initial value of the learning rate to 0.01 and adopt an adaptive adjustment strategy;

[0044] 5. Set the number of training epochs to 100 and randomly select 80% of the data in each epoch;

[0045] 6. Use 20% of the data for validation and stop training when the validation error is less than 0.1.

[0046] Furthermore, the channel capacity matrix equation is specifically expressed as follows:

[0047]

[0048] In the formula, C i，j is the channel capacity (bit / s) of the i-th sub-channel at time j, B i，j is the bandwidth (Hz) of the i-th sub-channel at time j, P i，j is the transmit power (W), Hi，j is the channel gain, N 0 is the power spectral density of Gaussian white noise (W / Hz), I i，j is the interference power (W), α, β, γ are undetermined coefficients, and t is the time variable (s).

[0049] The power allocation matrix equation is specifically expressed as follows:

[0050]

[0051] In the formula, P opt is the optimal power allocation value (W), λ is the Lagrange multiplier, N k is the noise power (W) of the k-th subchannel, h k is the channel response of the k-th subchannel, θ k is the phase angle (rad), δ is the correction coefficient, K is the total number of subchannels, (x) + = max(0, x).

[0052] The spectral efficiency matrix equation is specifically expressed as follows:

[0053]

[0054] In the formula, η s，t is the spectral efficiency (bit / s / Hz) at time t, R n，t is the data rate (bit / s) of the n-th subcarrier at time t, B n is the bandwidth (Hz) of the n-th subcarrier, p m is the bit error rate of the m-th subcarrier, μ, ω are weight coefficients, f i is the center frequency (Hz) of the i-th subcarrier.

[0055] The delay compensation equation is specifically expressed as follows:

[0056]

[0057] In the formula, τ comp is the delay compensation value (s), τ base is the reference delay (s), ξ is the attenuation coefficient, d is the transmission distance (m), ρ is the gain coefficient, τ l is the delay (s) of the l-th path, τ th is the delay threshold (s), κ is the adjustment coefficient, σ is the complex domain compensation coefficient, A q is the amplitude of the q-th harmonic component, f qis the frequency (Hz) of the q-th harmonic component, and j is the imaginary unit. The reason for using the complex form here is that both the amplitude and phase of the signal need to be compensated. The term (1 + j) makes the compensation include both the real part (amplitude compensation) and the imaginary part (phase compensation); the complex form can more conveniently perform calculations for signal phase rotation and time delay compensation.

[0058] The method for obtaining parameters is as follows:

[0059] 1. B i，j Obtained by measuring with a spectrum analyzer. The specific steps are as follows:

[0060] Step 1: Set the frequency range of the spectrum analyzer to 3 KHz - 510 MHz;

[0061] Step 2: Record the spectrum occupancy within 60 s in the maximum hold mode;

[0062] Step 3: Calculate the bandwidth of each sub-channel according to the spectrogram.

[0063] 2. H i，j Obtained by channel measurement. The specific steps are as follows:

[0064] Step 1: Transmit a pilot signal with a known power;

[0065] Step 2: The receiving end measures the power of the pilot signal;

[0066] Step 3: Calculate the channel gain according to the transmitted power and the received power.

[0067] 3. τ l Obtained by time delay scanning. The specific steps are as follows:

[0068] Step 1: Transmit a narrow pulse signal;

[0069] Step 2: The receiving end uses the correlation detection method to identify the multipath components;

[0070] Step 3: Record the arrival time differences of each path component.

[0071] 4. Bit error rate p m Obtained by bit error rate testing. The specific steps are as follows:

[0072] Step 1: Transmit a known bit sequence;

[0073] Step 2: The receiving end counts the number of error bits;

[0074] Step 3: Calculate the bit error rate = number of error bits / total number of bits.

[0075] The default value ranges of the coefficients are as follows: α ∈ [0.1, 0.5]; β ∈ [0.01, 0.1]; γ ∈ [0.001, 0.01]; δ ∈ [0.1, 1]; μ ∈ [0.5, 2]; ω ∈ [0.1, 1]; ξ ∈ [0.001, 0.01]; ρ ∈ [0.1, 1]; k ∈ [1, 10]; σ ∈ [0.1 + 0.1j, 1 + j].

[0076] Steps for obtaining the delay threshold:

[0077] (1) Measure the minimum delay τ of the system min ;

[0078] (2) Measure the maximum delay τ of the system max ;

[0079] (3) Calculate the delay threshold τ th :

[0080] τ th = τ min + X 4 (τ max - τ min );

[0081] In the formula, χ 4 is the delay margin coefficient, and its value range is [0.4, 0.6]; default value: τ th = 10ms;

[0082] The preset threshold is the channel quality threshold, and the obtaining steps are as follows:

[0083] (1) Calculate the signal-to-noise ratio SNR; (2) Calculate the bit error rate BER; (3) Calculate the channel quality threshold Q th :

[0084] Q th = X 5 · SNR · (1 - BER) 2 ; In the formula, χ 5 is the quality coefficient, and its value range is [0.5, 0.7]; default value: Q th = 15dB.

[0085] Compared with the prior art, the beneficial effects of a HPLC and micro-power wireless dual-mode communication method provided by the present invention are as follows:

[0086] 1. Improve the spectrum utilization efficiency. Traditional HPLC and micro-power wireless each occupy different frequency bands, while in this solution, through OFDM frequency division multiplexing, effective multiplexing of the two signals in the spectrum is achieved, greatly improving the spectrum utilization rate.

[0087] 2. Enhance communication reliability. Since there is mutual interference between HPLC and micro-power wireless communication, this solution allocates non-interfering frequency bands for the two signals through dynamic spectrum resource allocation, effectively avoiding the interference effect and improving the overall communication quality.

[0088] 3. Achieve time synchronization. Due to different transmission mechanisms, there are often large time-delay differences between HPLC and micro-power wireless. This solution uses time synchronization and time-delay compensation technologies to eliminate the time-delay differences between the two signals and ensure time synchronization for end-to-end transmission.

[0089] 4. Achieve adaptive switching. In a complex channel environment, the adaptive receiving algorithm of this solution can dynamically select a communication link with better signal quality to ensure the reliability of data transmission and provide stable communication services for upper-layer applications.

[0090] In summary, the present invention solves the technical problem that currently, HPLC and micro-power wireless communication often use independent communication carriers and transmission protocols, making it difficult to achieve effective coordination. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 It is a flowchart of the steps executed by the modulation end;

[0092] Figure 2 It is a flowchart of the steps executed by the demodulation end;

[0093] Figure 3 It is a spectrum distribution characteristic diagram of HPLC and micro-power wireless signals;

[0094] Figure 4 It is a schematic diagram of the channel capacity distribution of the dual-mode communication system;

[0095] Figure 5 It is a comparison diagram of the time-delay characteristics of HPLC and micro-power wireless signals. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0096] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0097] As Figure 1-2 shown, it is a flowchart of the steps executed by the modulation end and the demodulation end of a dual-mode communication method between HPLC and micro-power wireless provided by the present invention. This method is used to achieve coordinated transmission of power line carrier communication and micro-power wireless communication, including a modulation end method and a demodulation end method;

[0098] The modulation end method includes the following steps:

[0099] S11. Collect HPLC signals and micro-power wireless signals, and perform band-pass filtering on the HPLC signals;

[0100] S12. Control the orthogonal frequency division multiplexing (OFDM) modulation and demodulation platform, map the HPLC signals to the first carrier frequency band of the OFDM modulation and demodulation platform, and map the micro-power wireless signals to the second carrier frequency band of the OFDM modulation and demodulation platform;

[0101] S13. Based on spectrum sensing technology, perform channel scanning on the first carrier frequency band and the second carrier frequency band to obtain the spectrum occupancy information of the HPLC channel and the micro-power wireless channel;

[0102] S14. Adopt a dynamic spectrum resource allocation model, and according to the spectrum occupancy information, allocate non-interfering frequency bands for HPLC communication and micro-power wireless communication;

[0103] S15. Adopt time-sensitive network technology to establish a unified time reference and generate a time synchronization signal;

[0104] S16. According to the time synchronization signal, calculate the transmission delays of HPLC communication and micro-power wireless communication;

[0105] S17. Input the transmission delays into the delay compensation equation, and output the delay compensation coefficient and phase correction parameters for compensating the data transmission of HPLC communication and micro-power wireless communication;

[0106] S18. According to the delay compensation coefficient and phase correction parameters, perform OFDM modulation on the HPLC signals and the micro-power wireless signals, and send the modulated signals through the channel;

[0107] Among them, the demodulation-end method includes the following steps:

[0108] S21. Receive the HPLC signals and the micro-power wireless signals after delay compensation, and perform signal strength measurement;

[0109] S22. According to the signal strength measurement results, select the communication channel with better signal quality as the main channel, and the other channel as the backup channel;

[0110] S23. Adopt an adaptive modulation and demodulation method to demodulate the signals on the main channel. When the signal quality of the main channel is lower than the preset threshold, switch to the backup channel;

[0111] S24. Perform channel decoding and data recovery on the demodulated data to complete the reception of the dual-mode communication data.

[0112] The following describes the specific implementation manners of the above steps in detail:

[0113] Step S11: Collect the HPLC signal and the micro-power wireless signal, and perform band-pass filtering on the HPLC signal. First, collect two electrical signals transmitted by the HPLC device and the micro-power wireless device. Then, use a band-pass filter to filter the HPLC signal to remove high-frequency and low-frequency interference components in the signal and retain the effective signal frequency band. The purpose of this step is to separate and obtain the two communication signals to prepare for subsequent orthogonal frequency division multiplexing.

[0114] Step S12: Control the orthogonal frequency division multiplexing modulation and demodulation platform to map the HPLC signal to the first carrier frequency band and the micro-power wireless signal to the second carrier frequency band. Specifically, first set the parameters of the orthogonal frequency division multiplexing (OFDM) modulation and demodulation platform, including the number of subcarriers, carrier spacing, symbol period, etc. Then, modulate the processed HPLC signal to the first carrier frequency band of the platform and the micro-power wireless signal to the second carrier frequency band. The purpose of this is to achieve frequency reuse of the two communication signals and improve the spectrum utilization efficiency. Here, the first carrier frequency band is set from 3 kHz to 500 kHz, and the second carrier frequency band is set from 470 MHz to 510 MHz.

[0115] Step S13: Based on spectrum sensing technology, perform channel scanning on the first carrier frequency band and the second carrier frequency band to obtain the spectrum occupancy information of the HPLC channel and the micro-power wireless channel. First, use a spectrum analyzer to perform a 60-second spectrum scan in the frequency band from 3 kHz to 510 MHz and record the spectrum occupancy. Then, analyze the spectrum occupancy status of the HPLC channel and the micro-power wireless signal on each subcarrier according to the scan results to obtain the spectrum distribution of the two signals in the time-frequency domain. The purpose of this step is to obtain the spectrum resource allocation of the current channel environment and provide a basis for subsequent dynamic resource management.

[0116] Step S14: Adopt a dynamic spectrum resource allocation model to allocate non-interfering frequency bands for HPLC communication and micro-power wireless communication according to the spectrum occupancy information. The dynamic spectrum resource allocation model includes three matrix equations and a fusion allocation network:

[0117] The channel capacity matrix equation is used to calculate the potential data transmission capabilities of the HPLC and micro-power wireless channels. The input parameters include channel bandwidth, transmit power, channel gain, noise power spectral density, and interference power, and the output is the capacity value and capacity change trend of each sub-channel.

[0118] The power allocation matrix equation is used to allocate the optimal transmit power for each sub-channel according to the channel state. The input parameters include channel response, noise power, phase angle, and the number of sub-channels, and the output is the optimal power allocation scheme that satisfies the total power constraint.

[0119] The spectral efficiency matrix equation is used to evaluate the utilization efficiency of spectral resources. The input parameters include subcarrier data rate, bandwidth, bit error rate, and frequency information, and the output is the overall spectral efficiency and efficiency gradient of the system.

[0120] The fusion allocation network adopts a lightweight neural network and makes intelligent decisions by synthesizing the output results of three matrix equations. The input is channel capacity, power allocation, and spectral efficiency, and the output is the optimal frequency band allocation scheme for HPLC and micro-power wireless channels. The structure of the neural network includes 15 input neurons, two hidden layers (8 and 4 neurons), and 2 output neurons, using the ReLU activation function and Dropout regularization.

[0121] Through the dynamic spectrum resource allocation model, it is possible to adjust the allocation of HPLC and micro-power wireless signals in the frequency domain in real time according to the current channel conditions, avoid interference between the two communication signals, and improve the spectral utilization efficiency.

[0122] Step S15: Establish a unified time reference using time-sensitive network technology to generate a time synchronization signal. Specifically, deploy precision clock synchronization devices at the modulation end and the demodulation end, and use time-sensitive network technology to establish a unified time reference at both ends. Then generate a time synchronization signal based on the time reference to provide a basis for subsequent delay compensation. The purpose of this step is to ensure time synchronization between HPLC and micro-power wireless communications and lay a foundation for the delay compensation of the two signals.

[0123] Step S16: Calculate the transmission delays of HPLC communication and micro-power wireless communication according to the time synchronization signal. Using the established time reference, measure the transmission time difference between the HPLC and micro-power wireless signals from the transmitter to the receiver to obtain the actual transmission delays of the two signals. The purpose of this step is to obtain the delay parameters of the two communication signals in the system as the input for delay compensation.

[0124] Step S17: Input the transmission delay into the delay compensation equation to output the delay compensation coefficient and phase correction parameter, which are used to perform delay compensation on the data transmission of HPLC communication and micro-power wireless communication. The delay compensation equation is as follows:

[0125]

[0126] where τ comp is the delay compensation value,

[0127] τ base is the reference delay, ξ is the attenuation coefficient, d is the transmission distance, ρ is the gain coefficient, τ l is the delay of the l-th path, τ th is the delay threshold, κ is the adjustment coefficient, σ is the complex domain compensation coefficient, A qis the amplitude of the q-th harmonic component, and f q is the frequency of the q-th harmonic component.

[0128] By calculating the compensation coefficient and phase correction parameters through the time-delay compensation equation and applying them to the data modulation of HPLC and micro-power wireless signals, the coherent interference caused by time-delay differences can be effectively suppressed, and the communication quality can be improved.

[0129] Step S18: According to the time-delay compensation coefficient and phase correction parameters, perform orthogonal frequency division multiplexing modulation on the HPLC signal and the micro-power wireless signal, and send the modulated signal through the channel. Specifically, apply the time-delay compensation coefficient and phase correction parameters calculated in step S17 to the OFDM modulation process of the HPLC and micro-power wireless signals. The two modulated signals are transmitted through the power line and the wireless channel. The purpose of this step is to achieve frequency division multiplexing transmission of the HPLC and micro-power wireless signals, suppress the interference caused by time-delay differences, and ensure high-quality transmission of the two signals.

[0130] The following introduces the specific implementation manner of the demodulation end:

[0131] Step S21: Receive the HPLC signal and the micro-power wireless signal after time-delay compensation, and perform signal strength measurement. First, the receiving end obtains the HPLC and micro-power wireless signals from the power line and the wireless channel. Then, use a power detection circuit to measure and record the received power of the two signals. The purpose of this step is to obtain the current signal quality information and provide a basis for subsequent adaptive modulation and demodulation.

[0132] Step S22: According to the signal strength measurement results, select the communication channel with better signal quality as the main channel, and the other channel as the backup channel. Specifically, according to the measurement results of step S21, compare the received powers of the HPLC channel and the micro-power wireless channel, and select the one with better signal quality as the main channel, and the other as the backup channel. The purpose of this step is to achieve adaptive switching of the communication link and ensure reliable data transmission of the system in a complex channel environment.

[0133] Step S23: Use an adaptive modulation and demodulation method to demodulate the signal of the main channel. When the signal quality of the main channel is lower than the preset threshold, switch to the backup channel. First, use an adaptive OFDM demodulation algorithm to demodulate the signal of the main channel. At the same time, continuously monitor the signal quality of the main channel. When the quality indicators (such as signal-to-noise ratio, bit error rate, etc.) are lower than the preset threshold, automatically switch to the backup channel for demodulation. The preset channel quality threshold Q th is 15 dB, which is comprehensively calculated from the signal-to-noise ratio and the bit error rate. The purpose of this step is to dynamically select the best demodulation path according to the current channel state and improve the reliability of communication.

[0134] Step S24: Perform channel decoding and data recovery on the demodulated data to complete the reception of dual-mode communication data. Specifically, first perform channel encoding and decoding on the demodulated digital signal to remove the errors introduced by the channel. Then, perform data recovery on the decoded bit stream to obtain the final HPLC and micro-power wireless communication data. The purpose of this step is to complete the end-to-end reception of dual-mode communication and provide reliable data services for upper-layer applications.

[0135] In summary, the modulation-end method and demodulation-end method of the present invention achieve the collaborative transmission of HPLC and micro-power wireless communication through key technologies such as spectrum sensing, dynamic resource allocation, and delay compensation, improving the spectrum utilization efficiency and communication reliability. The modulation-end method includes steps such as signal acquisition, frequency division multiplexing, dynamic resource allocation, and delay compensation; the demodulation-end method includes steps such as signal reception, adaptive demodulation, and channel decoding. These specific implementation manners ensure the efficient collaborative operation of the dual-mode communication system in a complex channel environment.

[0136] The present invention proposes a dual-mode communication method for HPLC and micro-power wireless, which realizes the efficient collaborative transmission of two communication signals through technical means such as spectrum sensing, dynamic resource allocation, and delay compensation.

[0137] Specifically, first use the orthogonal frequency division multiplexing (OFDM) technology to modulate the HPLC signal to the low-frequency carrier band and the micro-power wireless signal to the high-frequency carrier band to achieve spectrum multiplexing. Then, based on spectrum sensing, dynamically allocate non-interfering frequency band resources for the two signals to improve the spectrum utilization rate. At the same time, through time synchronization and delay compensation, suppress the coherent interference caused by the transmission delay difference to ensure the high-quality transmission of the two signals. At the demodulation end, adopt an adaptive reception algorithm to dynamically select the best demodulation path according to the current channel condition to further improve the communication reliability.

[0138] The key innovation of this technical solution lies in:

[0139] 1. Implement spectrum multiplexing using OFDM modulation. Different from the traditional independent frequency band transmission, this solution uses OFDM technology to map the HPLC and micro-power wireless signals to different carrier frequency bands to achieve spectrum multiplexing, greatly improving the spectrum utilization efficiency.

[0140] 2. Apply dynamic spectrum resource management. Through spectrum sensing and intelligent allocation algorithms, optimize the allocation of HPLC and micro-power wireless signals in the frequency domain in real time, avoid spectrum conflicts between the two signals, and improve the overall communication performance.

[0141] 3. Adopt delay compensation technology. Aiming at the delay difference between HPLC and micro-power wireless signals due to different transmission mechanisms, a delay compensation equation is proposed to effectively suppress coherent interference and ensure the time-domain synchronization of the two signals.

[0142] 4. Achieve adaptive reception switching. At the demodulation end, continuously monitor the channel condition and dynamically select the communication link with better signal quality to improve the overall communication reliability.

[0143] Generally speaking, the HPLC and micro-power wireless dual-mode communication method of the present invention fully integrates the advantages of the two communication technologies, realizes spectrum sharing, time synchronization and adaptive switching through innovative technical means, and greatly improves the spectrum utilization efficiency and reliability of the communication system.

[0144] Specifically, the principle of the present invention includes:

[0145] 1. Spectrum sharing:

[0146] Aiming at the problem that HPLC and micro-power wireless communications each occupy different frequency bands, the present invention uses OFDM technology to achieve spectrum sharing of the two communication signals. OFDM is an efficient multi-carrier modulation technology that divides a broadband signal into multiple orthogonal sub-carriers, and each sub-carrier is modulated at a lower symbol rate. This not only improves the spectrum utilization efficiency, but also can effectively suppress narrowband interference.

[0147] Specifically, the present invention modulates the HPLC signal to the low-frequency carrier of the OFDM platform and modulates the micro-power wireless signal to the high-frequency carrier. By reasonably designing the carrier frequencies of the two signals, they do not interfere with each other. At the same time, a dynamic spectrum resource management algorithm is also applied to monitor and optimize the allocation of the two signals in the frequency domain in real time to avoid spectrum conflicts.

[0148] 2. Time synchronization:

[0149] Due to different transmission mechanisms, there are often large delay differences between HPLC and micro-power wireless communications. This delay difference will cause coherent interference between the two signals at the receiving end and reduce the communication quality.

[0150] Therefore, the present invention adopts time synchronization technology to establish a unified time reference at the transmitting end and the receiving end. By measuring the actual transmission delay of the HPLC and micro-power wireless signals, the compensation delay is calculated and applied to the data modulation of the two signals. In this way, the delay difference between the two signals can be eliminated and the synchronization in the time domain can be ensured.

[0151] 3. Adaptive switching:

[0152] In a complex channel environment, the transmission quality of HPLC and micro-power wireless signals will change. To ensure the reliability of communication, the present invention adopts an adaptive reception algorithm at the receiving end.

[0153] Specifically, the receiving end continuously monitors the received power and bit error rate of the two signals, and dynamically selects the communication link with better signal quality as the main channel according to the preset channel quality index. When the quality of the main channel drops to the preset threshold, it will automatically switch to the backup channel to continue receiving data. This adaptive switching mechanism ensures the reliability of end-to-end communication.

[0154] The following provides a specific Embodiment 1 of the present invention. The specific implementation of each step in Embodiment 1 is described in detail as follows: The step S11 specifically includes:

[0155] First, collect two-way electrical signals transmitted by HPLC devices and micro-power wireless devices. For the HPLC signal, record its characteristic parameters in the time domain and frequency domain, denoted as x HPLC (t). For the micro-power wireless signal, record its characteristic parameters in the time domain and frequency domain, denoted as x wireless (t).

[0156] Then, use a band-pass filter to filter the HPLC signal. Let the transfer function of the filter be H(f), and the cut-off frequency be f c , where the value range of f c is [3 kHz, 500 kHz]. The filtered HPLC signal can be expressed as:

[0157]

[0158] The purpose of this step is to separate and obtain the two communication signals to prepare for subsequent orthogonal frequency division multiplexing.

[0159] The step S12 specifically includes:

[0160] First, set the parameters of the orthogonal frequency division multiplexing (OFDM) modulation and demodulation platform. Let the number of subcarriers be N, the carrier spacing be Δf, and the symbol period be T s .

[0161] Then, modulate the filtered HPLC signal to the first carrier frequency band of the OFDM platform. The center frequency range of the first carrier frequency band is [3 kHz, 500 kHz], and the bandwidth is B 1 . Modulate the micro-power wireless signal x wireless (t) to the second carrier frequency band of the OFDM platform. The center frequency range of the second carrier frequency band is [470 MHz, 510 MHz], and the bandwidth is B 2 .

[0162] The OFDM modulation process can be expressed as:

[0163]

[0164] Among them, represents the discrete Fourier transform, f 1 and f 2 are the center frequencies of the first carrier frequency band and the second carrier frequency band respectively, and p(t) is the OFDM symbol pulse.

[0165] The purpose of doing this is to achieve frequency multiplexing of two communication signals and improve the spectrum utilization efficiency.

[0166] The specific steps of step S13 include:

[0167] First, use a spectrum analyzer to perform a spectrum scan in the frequency band of [3 kHz, 510 MHz] for T = 60 s, and record the spectrum occupancy. The spectrum power density P(f, t) can be obtained, where f is the frequency and t is the time.

[0168] Then, according to the obtained spectrum information, analyze the spectrum occupancy status of the HPLC signal and the micro-power wireless signal on each subcarrier. The spectrum occupancy indicators U HPLC (k, t) and U wireless (k, t) can be defined, where k represents the k-th subcarrier.

[0169]

[0170] Among them, P th is the power detection threshold. Through these two indicators, the spectrum distribution of the HPLC channel and the micro-power wireless channel in the time-frequency domain can be obtained.

[0171] The purpose of this step is to obtain the spectrum resource allocation of the current channel environment and provide a basis for subsequent dynamic resource management.

[0172] The specific steps of step S14 include:

[0173] The dynamic spectrum resource allocation model includes the following three matrix equations and a fusion allocation network:

[0174] Channel capacity matrix equation:

[0175]

[0176] Among them, C i，j is the channel capacity (bit / s) of the i-th subchannel at time j, B i，j is the bandwidth (Hz) of the i-th subchannel at time j, P i，jis the transmission power (W), H i，j is the channel gain, N 0 is the power spectral density of Gaussian white noise (W / Hz), I i，j is the interference power (W), α, β, γ are undetermined coefficients, and t is the time variable (s). This equation is used to calculate the potential data transmission capacity of the HPLC and micro-power wireless channels.

[0177] Power allocation matrix equation:

[0178]

[0179] where P opt is the optimal power allocation value (W), λ is the Lagrange multiplier, N k is the noise power (W) of the k-th sub-channel, h k is the channel response of the k-th sub-channel, θ k is the phase angle (rad), δ is the correction coefficient, K is the total number of sub-channels, (x) + = max(0, x). This equation is used to allocate the optimal transmission power to each sub-channel according to the channel state.

[0180] Spectral efficiency matrix equation:

[0181]

[0182] where η s，t is the spectral efficiency (bit / s / Hz) at time t, R n，t is the data rate (bit / s) of the n-th sub-carrier at time t, B n is the bandwidth (Hz) of the n-th sub-carrier, p m is the bit error rate of the m-th sub-carrier, μ, ω are weight coefficients, f i is the center frequency (Hz) of the i-th sub-carrier. This equation is used to evaluate the utilization efficiency of spectral resources.

[0183] The fusion allocation network adopts a lightweight neural network. The input is the output results of three matrix equations (channel capacity, power allocation, spectral efficiency), and the output is the optimal frequency band allocation scheme for the HPLC and micro-power wireless channels. The network structure includes 15 input neurons, two hidden layers (8 and 4 neurons), and 2 output neurons, using the ReLU activation function and Dropout regularization.

[0184] Through the dynamic spectrum resource allocation model, it is possible to adjust the allocation of HPLC and micro-power wireless signals in the frequency domain in real time according to the current channel conditions, avoid interference between the two communication signals, and improve the spectral utilization efficiency.

[0185] The specific steps of step S15 include:

[0186] Deploy precise clock synchronization devices at the modulation end and the demodulation end, and establish a unified time reference at both ends using time-sensitive network technology. Denote the time reference as t b (t), where t is the current time.

[0187] Then generate a time synchronization signal t s (t), which can be expressed as:

[0188] t s (t) = t b (t) - t b (0);

[0189] The purpose of this step is to ensure time synchronization between HPLC and micro-power wireless communication, laying a foundation for subsequent delay compensation.

[0190] The specific steps of step S16 include:

[0191] Utilize the established time reference t b (t) to measure the transmission delays of HPLC signals and micro-power wireless signals from the transmitter to the receiver. Define the transmission delay of HPLC signals as τ HPLC , and the transmission delay of micro-power wireless signals as τ wireless .

[0192]

[0193] Among them, are the transmission times of HPLC and micro-power wireless signals respectively, are the reception times of HPLC and micro-power wireless signals respectively.

[0194] The purpose of this step is to obtain the delay parameters of the two communication signals in the system as the input for delay compensation.

[0195] The specific steps of step S17 include:

[0196] Calculate the delay compensation coefficient and phase correction parameter using the delay compensation equation:

[0197]

[0198] Among them, τ comp is the delay compensation value (s), τ base is the reference delay (s), ξ is the attenuation coefficient, d is the transmission distance (m), ρ is the gain coefficient, τ l is the delay of the l-th path (s), τ th is the delay threshold (s), κ is the adjustment coefficient, σ is the complex domain compensation coefficient, A qis the amplitude of the q-th harmonic component, and f q is the frequency (Hz) of the q-th harmonic component.

[0199] Applying the calculated time delay compensation coefficient and phase correction parameter to the data modulation of HPLC and micro-power wireless signals can effectively suppress the coherent interference caused by time delay differences and improve the communication quality.

[0200] The specific steps of step S18 include:

[0201] Applying the time delay compensation coefficient τ comp calculated in step S17 and the phase correction parameter σ to the OFDM modulation process of HPLC and micro-power wireless signals. The OFDM-modulated signal can be expressed as:

[0202]

[0203] where X HPLC (k) and X wireless (k) are the frequency domain signals of HPLC and micro-power wireless signals on the k-th subcarrier respectively, f 1 and f 2 are the center frequencies of the first carrier frequency band and the second carrier frequency band respectively, and p(t) is the OFDM symbol pulse.

[0204] The two modulated signals are transmitted through the power line and the wireless channel. The purpose of this step is to achieve frequency division multiplexing transmission of HPLC and micro-power wireless signals, suppress the interference caused by time delay differences, and ensure high-quality transmission of the two signals.

[0205] The specific steps of step S21 include:

[0206] First, the receiving end obtains the HPLC signal S HPLC (t) and the micro-power wireless signal s wireless (t) from the power line and the wireless channel.

[0207] Then, a power detection circuit is used to measure and record the received power of the two signals. For the HPLC signal, record its received power as P HPLC ; for the micro-power wireless signal, record its received power as P wireless .

[0208] The purpose of this step is to obtain the current signal quality information and provide a basis for subsequent adaptive modulation and demodulation.

[0209] The specific steps of step S22 include:

[0210] According to the measurement results of step S21, compare the received powers P HPLCand P wireless Select the path with better signal quality (i.e., the path with higher received power) as the main channel, and the other path as the backup channel. Denote the received power of the main channel as P main and the received power of the backup channel as P backup .

[0211]

[0212] The purpose of this step is to achieve the adaptive switching of the communication link and ensure the reliable transmission of data in a complex channel environment.

[0213] The specific steps of step S23 include:

[0214] First, demodulate the signal of the main channel using the adaptive OFDM demodulation algorithm. At the same time, continuously monitor the signal quality of the main channel, that is, the received power P main and the bit error rate BER main . When the signal quality index Q main of the main channel is lower than the preset threshold Q th , automatically switch to the backup channel for demodulation.

[0215] Q main = X 5 ·SNR main , (1 - BER main ) 2 ;

[0216] Q th = 15dB;

[0217] Among them, SNR main = P main / N 0 is the signal-to-noise ratio of the main channel, χ 5 is the quality coefficient, and its value range is [0.5, 0.7].

[0218] The purpose of this step is to dynamically select the best demodulation path according to the current channel state and improve the reliability of communication.

[0219] The specific steps of step S24 include:

[0220] First, perform channel encoding and decoding on the demodulated digital signal to remove the errors introduced by the channel. The encoding and decoding operations can be denoted as and

[0221]

[0222] Then, perform data recovery on the decoded bit stream to obtain the final HPLC and micro-power wireless communication data. Denote the recovered data as and

[0223] The purpose of this step is to complete the end-to-end reception of dual-mode communication and provide reliable data services for upper-layer applications.

[0224] To further understand and implement the present invention, an embodiment 2 of a specific shared scenario of the present invention is provided below: An intelligent power grid enterprise is deploying a distribution automation system based on power line carrier communication (HPLC) and micro-power wireless communication. This system is mainly applied to urban distribution networks, and its coverage includes substations, distribution lines, and user-side terminal devices. To improve the reliability of communication and the spectrum utilization efficiency, the enterprise decides to adopt the HPLC and micro-power wireless dual-mode communication method proposed by the present invention. The following is its specific implementation situation.

[0225] System deployment:

[0226] The topological structure of this distribution automation system is shown in Table 1. An HPLC master station is deployed at the substation end to collect and process the operation data of the substation; HPLC relay nodes are deployed along the distribution lines to undertake the tasks of line monitoring and fault warning; micro-power wireless terminal devices are deployed on the user side to achieve functions such as electricity meter data collection and load control. The HPLC master station and relay nodes are connected through power lines, while the micro-power wireless terminals communicate wirelessly with the nearby HPLC relay nodes. The entire system constitutes a hybrid communication network.

[0227] Table 1 Topological structure of the distribution automation system

[0228] equipment quantity communication mode HPLC master station 1 power line HPLC relay node 100 power line micro-power wireless terminal 10000 micro-power wireless

[0229] System parameters: When deploying this system, the enterprise's technical personnel measured and set the key parameters of HPLC and micro-power wireless communication as follows:

[0230] 1. HPLC signal parameters: Center frequency range: 3 kHz to 500 kHz; Signal bandwidth: 10 kHz / subchannel; Transmit power: 0.1 W / subchannel; Channel gain: 0 to 40 dB; Noise power spectral density: -150 dBm / Hz; Interference power: -80 dBm;

[0231] 2. Micro-power wireless signal parameters: Center frequency range: 470 MHz to 510 MHz; Signal bandwidth: 1 MHz / subchannel; Transmit power: 10 mW / subchannel; Channel gain: 0 to 30 dB; Noise power spectral density: -160 dBm / Hz; Interference power: -90 dBm;

[0232] 3. OFDM Parameters: Number of subcarriers: 256; Carrier spacing: 39.0625 kHz; Symbol period: 25.6 μs;

[0233] 4. Delay characteristics: Minimum HPLC delay: 5 ms; Maximum HPLC delay: 20 ms; Minimum micro-power wireless delay: 1 ms; Maximum micro-power wireless delay: 10 ms;

[0234] 5. Bit error rate: Maximum HPLC bit error rate: 10 -4 ; Maximum micro-power wireless bit error rate: 10 -5 ;

[0235] As Figure 3 shown, it is the spectrum distribution characteristic diagram of HPLC and micro-power wireless signals. The left figure shows the power spectral density distribution of HPLC signals in the range of 3 kHz to 500 kHz, and the right figure shows the power spectral density distribution of micro-power wireless signals in the range of 470 MHz to 510 MHz. It can be clearly seen the separation characteristics of the two signals in the frequency domain.

[0236] Through the measurement and setting of the above parameters, the enterprise ensures the basic working conditions of HPLC and micro-power wireless communications. Next, for the specific implementation of the present invention, the enterprise technicians carried out the following steps:

[0237] Step S11: Signal acquisition and filtering

[0238] First, the HPLC master station and the micro-power wireless terminal device respectively collect the original communication signals from the power line and the wireless channel. For HPLC signals, due to their narrow bandwidth, only band-pass filtering needs to be performed within the frequency band of 3 kHz to 500 kHz.

[0239] The transfer function H(f) of the filter is designed as follows:

[0240]

[0241] After filtering, the spectrum distribution of HPLC signals is more concentrated, which is beneficial to subsequent OFDM modulation.

[0242] Step S12: OFDM frequency division multiplexing

[0243] Map the processed HPLC signals and micro-power wireless signals to different carrier frequency bands of the OFDM platform respectively.

[0244] For HPLC signals, they are modulated to the low-frequency carrier of the OFDM platform, and the center frequency range is f 1 = 3 kHz to 500 kHz. The subcarrier spacing Δf = 39.0625 kHz, and a total of 128 subcarriers are allocated.

[0245] For the micro-power wireless signal, it is modulated onto the high-frequency carrier of the OFDM platform, and the center frequency range is f 2 = 470 MHz to 510 MHz. The sub-carrier spacing is still Δf = 39.0625 kHz, and 128 sub-carriers are allocated.

[0246] The purpose of doing this is to achieve the frequency-domain multiplexing of HPLC and micro-power wireless signals and improve the spectrum utilization efficiency.

[0247] Step S13: Spectrum scanning and analysis

[0248] To avoid interference between HPLC and micro-power wireless signals in the spectrum, it is necessary to scan and analyze the current spectrum usage situation.

[0249] Both the HPLC master station and the micro-power wireless terminal device use a spectrum analyzer to perform a 60-second spectrum scan in the frequency band from 3 kHz to 510 MHz and record the spectrum power density P(f, t). According to the scan results, calculate the spectrum occupancy indicators U HPLC (k, t) and U wireless (k, t) for the HPLC signal and the micro-power wireless signal on each sub-carrier respectively.

[0250]

[0251] Among them, P th is the power detection threshold, taking -90 dBm. Through these two indicators, the spectrum occupancy distribution of HPLC and micro-power wireless signals in the time-frequency domain can be obtained.

[0252] Step S14: Dynamic spectrum resource allocation

[0253] According to the spectrum occupancy information obtained in step S13, the enterprise dynamically allocates the sub-carriers of HPLC and micro-power wireless signals using a dynamic spectrum resource allocation model.

[0254] First, calculate the potential data transmission capacity of each sub-channel using the channel capacity matrix equation:

[0255]

[0256] Among them, C i，j is the channel capacity (bit / s) of the i-th sub-channel at time j, B i，j is the bandwidth (10 kHz), P i，j is the transmit power (0.1 W), H i，j is the channel gain (0 to 40 dB), N 0 is the noise power spectral density (-150 dBm / Hz), I i，jis the interference power (-80 dBm).

[0257] Then, the optimal transmission power is allocated to each sub-channel by using the power allocation matrix equation:

[0258]

[0259] where λ is the Lagrange multiplier, N k is the noise power of the k-th sub-channel, h k is the channel response, and θ k is the phase angle.

[0260] Then, the utilization efficiency of the spectrum resources is evaluated by using the spectral efficiency matrix equation:

[0261]

[0262] where η s，t is the spectral efficiency (bit / s / Hz) at time t, R n，t is the data rate (bit / s) of the n-th sub-carrier, and p m is the bit error rate of the m-th sub-carrier.

[0263] Finally, the fusion distribution network combines the results of the above three matrix equations and outputs the optimal allocation scheme of the HPLC and micro-power wireless signals in the frequency domain, as Figure 4 shown, which is a schematic diagram of the channel capacity distribution of the dual-mode communication system. The X-axis represents the channel gain, the Y-axis represents the signal-to-noise ratio, and the Z-axis represents the channel capacity. The depth of the color represents the magnitude of the channel capacity. Through this figure, the relationship between the system capacity and the channel gain and the signal-to-noise ratio can be intuitively seen.

[0264] Through this dynamic spectrum resource allocation mechanism, it can be ensured that the HPLC and micro-power wireless signals do not interfere with each other in the spectrum, and the overall spectrum utilization efficiency is improved.

[0265] Steps S15 & S16: Time synchronization and delay measurement

[0266] To suppress the coherent interference caused by the transmission delay difference between the HPLC and micro-power wireless signals, time synchronization of the two signals needs to be achieved.

[0267] Precise clock synchronization devices are deployed at both the HPLC master station and the micro-power wireless terminal device, and a unified time reference t b (t) is established through the time-sensitive network technology. Then, according to the time reference, the actual transmission delays of the HPLC signal and the micro-power wireless signal are measured respectively:

[0268]

[0269] where They are the transmission moments of HPLC and micro-power wireless signals respectively. They are the reception moments respectively.

[0270] As Figure 5 shown, it is a comparison chart of the time-delay characteristics of HPLC and micro-power wireless signals. The horizontal axis represents time, and the vertical axis represents the transmission time delay. The blue solid line represents the time-delay change of the HPLC signal, and the red dashed line represents the time-delay change of the micro-power wireless signal. It can be seen from the figure the time-delay difference between the two signals and their dynamic change characteristics. Through time synchronization and time-delay measurement, necessary parameters for subsequent time-delay compensation are provided.

[0271] Step S17: Time-delay compensation

[0272] According to the actual transmission time delays τ HPLC and τ wireless of the HPLC and micro-power wireless signals measured in step S16, the enterprise calculates the corresponding time-delay compensation coefficients τ comp，HPLC and τ comp，wireless .

[0273] Adopt the time-delay compensation equation:

[0274]

[0275] where τ l is the time delay of the l-th transmission path, and A q and f q are the amplitude and frequency of the q-th harmonic component respectively.

[0276] Applying the calculated time-delay compensation coefficients to the OFDM modulation process of the HPLC and micro-power wireless signals can effectively suppress the coherent interference between the two signals.

[0277] Step S18: Dual-mode signal transmission

[0278] Finally, the HPLC master station and the micro-power wireless terminal device respectively perform OFDM modulation on the HPLC signal and the micro-power wireless signal after time-delay compensation, and send them out through the power line and the wireless channel. The OFDM modulation expression of the HPLC signal is:

[0279]

[0280] The OFDM modulation expression of the micro-power wireless signal is:

[0281]

[0282] where X HPLC (k) and X wireless(k) is the frequency-domain signal of HPLC and micro-power wireless signal on the k-th subcarrier, σ HPLC and σ wireless are phase correction parameters, and p(t) is the OFDM symbol pulse.

[0283] Through this way of OFDM frequency division multiplexing and time delay compensation, HPLC and micro-power wireless signals achieve cooperative transmission and avoid mutual interference.

[0284] Receiver processing:

[0285] At the receiver, the HPLC relay node and the micro-power wireless terminal device respectively receive signals from the HPLC master station and the wireless channel.

[0286] First, measure the received powers P HPLC and P wireless , and select the path with better signal quality as the main channel, and the other path as the backup channel.

[0287]

[0288] Then, use the adaptive OFDM demodulation algorithm to demodulate the signal of the main channel. At the same time, continuously monitor the signal quality of the main channel, that is, the received power P main and the bit error rate BER main . When the signal quality index Q main = 0.6·SNR main ·(1 - BER main ) 2 is lower than 15 dB, automatically switch to the backup channel for demodulation.

[0289] Finally, perform channel coding and decoding on the demodulated digital signal, remove the errors introduced by the channel, and complete data recovery to form the final HPLC and micro-power wireless communication data.

[0290] System verification:

[0291] To verify the performance of the proposed solution of the present invention, the enterprise deployed the HPLC and micro-power wireless dual-mode communication system in the actual distribution network environment and conducted a one-month trial operation.

[0292] The trial operation results show that the system has significant improvements in aspects such as spectrum utilization efficiency, communication reliability, and delay performance:

[0293] 1. Spectrum utilization efficiency:

[0294] Compared with the traditional solution that uses independent frequency bands, the spectrum utilization rate of the solution of the present invention has increased by about 80%. The effective multiplexing of HPLC and micro-power wireless signals in the frequency domain has greatly improved the utilization efficiency of spectrum resources.

[0295] 2. Communication reliability:

[0296] In a complex power line and wireless channel environment, the end-to-end communication interruption probability of the system has been reduced by 45%. The dynamic spectrum resource allocation and adaptive reception switching mechanism effectively cope with the impact brought by channel changes and ensure the communication reliability.

[0297] 3. Delay performance:

[0298] The end-to-end delay difference between HPLC and micro-power wireless signals has been reduced to within 5 ms, showing a significant improvement compared with the 10 ms difference in the traditional solution. The application of time synchronization and delay compensation technologies ensures a high degree of coordination between the two signals in the time domain.

[0299] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered within the protection scope of the present invention.

Claims

1. A HPLC and micro-power wireless dual-mode communication method, characterized in that: Used to realize the coordinated transmission of power line carrier communication and micro-power wireless communication, including a modulation end method and a demodulation end method; The modulation end method comprises the following steps: S11, collecting HPLC signals and micro-power wireless signals, and performing band-pass filtering on the HPLC signals; S12, controlling the OFDM platform to map the HPLC signal to a first carrier frequency band of the OFDM platform, and mapping the micro-power wireless signal to a second carrier frequency band of the OFDM platform; S13, performing channel scanning on the first carrier frequency band and the second carrier frequency band based on spectrum sensing technology to obtain spectrum occupancy information of HPLC channels and micro-power wireless channels; S14, using a dynamic spectrum resource allocation model, and allocating frequency bands that do not interfere with each other for HPLC communication and micro-power wireless communication according to the spectrum occupancy information; S15. Use time-sensitive network technology to establish a unified time reference and generate a time synchronization signal; S16, calculating the transmission delay of HPLC communication and micro-power wireless communication according to the time synchronization signal; S17, inputting the transmission delay into a delay compensation equation, outputting a delay compensation coefficient and a phase correction parameter, for delay compensation of data transmission of HPLC communication and micro-power wireless communication; S18, performing orthogonal frequency division multiplexing modulation on the HPLC signal and the micro-power wireless signal according to the delay compensation coefficient and the phase correction parameter, and sending the modulated signal through the channel; The demodulation end method comprises the following steps: S21, receiving the delay-compensated HPLC signal and the micro-power wireless signal, and measuring the signal strength; S22, according to the signal strength measurement result, selecting a communication channel with better signal quality as a main channel and another channel as a backup channel; S23, demodulating the signal of the primary channel by using an adaptive modulation and demodulation method, and switching to the backup channel when the signal quality of the primary channel is lower than a preset threshold; S24, performing channel decoding and data recovery on the demodulated data to complete the reception of the dual-mode communication data; The dynamic spectrum resource allocation model includes a channel capacity matrix equation, a power allocation matrix equation, a spectrum efficiency matrix equation and a fusion allocation network; The channel capacity matrix equation is used to calculate the potential data transmission capacity of HPLC and micro-power wireless channels. The input is the channel bandwidth, transmission power, channel gain, noise power spectrum density and interference power. The output is the channel capacity value and capacity change trend of each sub-channel. The power allocation matrix equation is used to allocate the optimal transmission power to each subchannel according to the channel state, the input is the channel response, noise power, phase angle and number of subchannels, and the output is the optimal power allocation scheme that meets the total power constraint; The spectrum efficiency matrix equation is used to evaluate the utilization efficiency of spectrum resources. The input is subcarrier data rate, bandwidth, bit error rate and frequency information, and the output is the spectrum efficiency and efficiency gradient of the whole system. Among them, the fusion allocation network adopts a lightweight neural network to integrate the output results of the three matrix equations and make intelligent decisions. The input is the channel capacity value, power allocation plan and spectrum efficiency of the three equations, and the output is the optimal frequency band allocation plan for HPLC and micro-power wireless channels. The specific structure is: the input layer contains 15 neurons, the two hidden layers contain 8 and 4 neurons respectively, and the output layer contains 2 neurons, using ReLU activation function and Dropout regularization.

2. A HPLC and micro-power wireless dual-mode communication method according to claim 1, characterized in that: The steps of establishing the training data set of the fusion distribution network are specifically: Collect HPLC communication data under different power line channel environments; Collect micro-power wireless communication data at different spatial locations; Calculate the channel capacity, optimal power allocation and spectrum efficiency corresponding to each set of data; Record the actual frequency band allocation scheme and its communication performance; The communication performance is used as a label to construct a training dataset.

3. A HPLC and micro-power wireless dual-mode communication method according to claim 2, characterized in that: The channel capacity matrix equation is specifically expressed as follows: ; In the formula, For the The subchannel at time The channel capacity (bit / s), For the The subchannel at time Bandwidth (Hz), is the transmission power (W), is the channel gain, is the power spectral density of Gaussian white noise (W / Hz), is the interference power (W), is the coefficient to be determined, is the time variable (s).

4. A HPLC and micro-power wireless dual-mode communication method according to claim 3, characterized in that: The power allocation matrix equation is specifically expressed as follows: ; In the formula, is the optimal power allocation value (W), is the Lagrange multiplier, For the The noise power of each subchannel (W), For the The channel response of the subchannels is is the phase angle (rad), is the correction factor, is the total number of subchannels, .

5. A HPLC and micro-power wireless dual-mode communication method according to claim 4, characterized in that: The spectrum efficiency matrix equation is specifically expressed as follows: ; In the formula, For the moment Spectral efficiency (bit / s / Hz), For the subcarrier at time Data rate (bit / s), For the The bandwidth of the subcarriers (Hz), For the The bit error rate of the subcarriers, is the weight coefficient, For the The center frequency of the subcarriers (Hz); Indicates the total number of subcarriers; Indicates the spectrum efficiency.

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