HPLC (High Performance Liquid Chromatography) and micropower wireless dual-mode communication method

Abstract

The invention provides an HPLC (High Performance Liquid Chromatography) and micropower wireless dual-mode communication method, which belongs to the technical field of multiplexing communication, is used for realizing cooperative transmission of power line carrier communication and micropower wireless communication, and comprises a modulation end method and a demodulation end method. According to the modulation end, firstly, HPLC and micropower wireless signals are collected, and band-pass filtering and spectrum sensing are carried out, so that frequency bands which do not interfere with each other are obtained. Then, a unified time reference is established, transmission delay is calculated, and delay compensation is carried out; and then, modulating and transmitting by adopting an orthogonal frequency division multiplexing technology. And at a receiving end, main and standby channels are selected according to the signal strength, and demodulation and data recovery are performed by adopting an adaptive modulation and demodulation technology. According to the scheme, the advantages of HPLC and micropower wireless are fully utilized, fusion of two communication technologies is achieved, and the technical problem that effective cooperation is difficult to achieve due to the fact that existing HPLC and micropower wireless communication often adopt independent communication carriers and transmission protocols is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of multiplexed communication, and in particular relates to a HPLC and micro-power wireless dual-mode communication method. Background Art

[0002] At present, smart grid and Internet of Things technologies are developing rapidly, among which power line carrier communication (HPLC) and micro-power wireless communication are becoming one of the important communication technologies. HPLC uses existing power lines as communication media to realize data transmission on power lines, and is widely used in power grid automation, smart home and other fields. Micro-power wireless communication uses radio electromagnetic waves to achieve long-distance wireless connection, and is used in industrial control, Internet of Things sensing and other scenarios. 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 micropower wireless communication need to work together to give full play to their respective advantages. For example, in smart grids, HPLC can be used for data backhaul on the backbone line, while micropower wireless can be used for the last mile device connection; in factory automation, HPLC is responsible for equipment networking on the production line, while micropower wireless is used for flexible connection of mobile devices. However, currently HPLC and micropower wireless communication often use independent communication carriers and transmission protocols, making it difficult to achieve effective collaboration.

[0004] The main problems are as follows:

[0005] 1. Low efficiency in spectrum resource utilization. The two communication systems occupy different frequency bands, making it difficult to reuse the spectrum, resulting in a waste of spectrum resources.

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

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

[0008] Therefore, a new technical solution is urgently needed to achieve the 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 a HPLC and micro-power wireless dual-mode communication method, which can solve the technical problem that current HPLC and micro-power wireless communications often use independent communication carriers and transmission protocols, making it difficult to achieve effective collaboration.

[0010] The present invention is achieved in that:

[0011] The present invention provides a HPLC and micro-power wireless dual-mode communication method 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;

[0012] The modulation end method comprises the following steps:

[0013] S11, collecting HPLC signals and micro-power wireless signals, and performing bandpass filtering on the HPLC signals; specifically: first, collecting two electrical signals transmitted by the HPLC device and the micro-power wireless device. Then, using a bandpass filter to filter the HPLC signal, remove the 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, 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 interval, symbol period, etc. Then, modulate the processed HPLC signal to the first carrier frequency band of the platform, specifically set at 3kHz to 500kHz; modulate the micro-power wireless signal to the second carrier frequency band, specifically set at 470MHz to 510MHz. The purpose of this is to achieve frequency reuse of the two communication signals and improve spectrum utilization efficiency.

[0015] S13. Based on spectrum sensing technology, the first carrier frequency band and the second carrier frequency band are scanned to obtain spectrum occupancy information of HPLC channel and micro-power wireless channel; specifically: first, a spectrum analyzer is used to perform a 60-second spectrum scan in the frequency band of 3kHz to 510MHz to record the spectrum occupancy. Then, according to the scanning results, the spectrum occupancy status of HPLC channel and micro-power wireless signal on each subcarrier is analyzed 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. A dynamic spectrum resource allocation model is used 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 to improve the spectrum utilization efficiency.

[0017] S15. Use time-sensitive network technology to establish a unified time reference and generate a time synchronization signal. Specifically, deploy precision clock synchronization devices at the modulation and demodulation ends, 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 that HPLC and micro-power wireless communication achieve time synchronization and lay the foundation for delay compensation of the two signals.

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

[0019] 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;

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

[0021] The demodulation end method comprises the following steps:

[0022] S21, receiving the HPLC signal and micro-power wireless signal after delay compensation, and measuring the signal strength; specifically: first, the receiving end obtains the HPLC and micro-power wireless signals from the power line and the wireless channel. Then, the power detection circuit is used 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.

[0023] S22, according to the signal strength measurement result, 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 result of step S21, compare the receiving power of the HPLC channel and the micro-power wireless channel, select the channel with better signal quality as the main channel, and the other channel as the backup channel. The purpose of this step is to achieve adaptive switching of the communication link to ensure that the system can reliably transmit data in a complex channel environment.

[0024] S23, demodulate the signal of the main channel using an adaptive modulation and demodulation method, and switch to the backup channel when the signal quality of the main channel is lower than a preset threshold; 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, and when the quality index (such as signal-to-noise ratio, bit error rate, etc.) is lower than a preset threshold Q th =15dB, it automatically switches to the backup channel for demodulation. The purpose of this step is to dynamically select the best demodulation path according to the current channel status to improve the reliability of communication.

[0025] S24, channel decoding and data recovery are performed on the demodulated data to complete the reception of dual-mode communication data; specifically: first, channel coding and decoding are performed on the demodulated digital signal to remove the error introduced by the channel. Then, data recovery is performed 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 3KHz to 500KHz, and the second carrier frequency band is specifically 470MHz to 510MHz.

[0027] On the basis of the above technical solution, the HPLC and micro-power wireless dual-mode communication method of the present invention can also be improved as follows:

[0028] 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] Furthermore, the channel capacity matrix equation is used to calculate the potential data transmission capacity of HPLC and micro-power wireless channels. The input is channel bandwidth, transmit power, channel gain, noise power spectral density and interference power. The output is the channel capacity value and capacity change trend of each sub-channel.

[0030] Furthermore, the power allocation matrix equation is used to allocate optimal transmission power to each subchannel according to the channel state, the input is the channel response, noise power, phase angle and the number of subchannels, and the output is the optimal power allocation scheme that meets the total power constraint.

[0031] Furthermore, 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 overall spectrum efficiency and efficiency gradient of the system.

[0032] Furthermore, 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 scheme and spectrum efficiency of the three equations, and the output is the optimal frequency band allocation scheme 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.

[0033] Furthermore, the step of establishing the training data set of the fusion distribution network is specifically:

[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 spectrum efficiency corresponding to each set of data;

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

[0038] The communication performance is used as a label to construct a training dataset.

[0039] The steps of training the fusion distribution network are specifically:

[0040] 1. Normalize the training data;

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

[0042] 3. The loss function uses mean square error;

[0043] 4. The initial value of the learning rate is set to 0.01, and an adaptive adjustment strategy is adopted;

[0044] 5. The number of training rounds is set to 100, and 80% of the data is randomly selected in each round;

[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 of the ith subchannel at time j (bit / s), B i，j is the bandwidth of the ith subchannel at time j (Hz), P i，j is the transmission power (W), Hi，j is the channel gain, N0 is the Gaussian white noise power spectral density (W / Hz), I i，j is the interference power (W), α, β, γ are unknown coefficients, and t is the time variable (s).

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

[0050]

[0051] Where P opt is the optimal power allocation value (W), λ is the Lagrange multiplier, N k is the noise power of the kth subchannel (W), h k is the channel response of the kth 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 spectrum efficiency matrix equation is specifically expressed as follows:

[0053]

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

[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 of the lth path (s), 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 qth harmonic component, f qis the frequency of the qth harmonic component (Hz), j is an imaginary unit. The complex form is used here because it is necessary to compensate for both the amplitude and phase of the signal. 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 signal phase rotation and delay compensation calculations.

[0058] The parameter acquisition method is:

[0059] 1.B i，j It is 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 3KHz-510MHz;

[0061] Step 2: Use the maximum hold mode to record the spectrum occupancy within 60 seconds;

[0062] Step 3: Calculate the bandwidth of each sub-channel based on the spectrum diagram.

[0063] 2.H i，j It is obtained through channel measurement. The specific steps are as follows:

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

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

[0066] Step 3: Calculate the channel gain based on the transmit power and the receive power.

[0067] 3. τ l It is obtained through time-delay scanning. The specific steps are as follows:

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

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

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

[0071] 4. Bit error rate p m It is obtained through bit error rate testing. The specific steps are as follows:

[0072] Step 1: Send 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 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 to obtain the latency threshold:

[0077] (1) Measurement system minimum delay τ min ;

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

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

[0080] τ th =τ min +X4(τ max -τ min );

[0081] Where χ4 is the delay margin coefficient, and its value range is [0.4, 0.6]; the default value is τ th =10ms;

[0082] The preset threshold is a channel quality threshold, and the acquisition steps are:

[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 =X5·SNR·(1-BER) 2 ; In the formula, χ5 is the quality coefficient, and its value range is [0.5, 0.7]; the default value is: Q th =15dB.

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

[0086] 1. Improve spectrum utilization efficiency. Traditional HPLC and micro-power wireless each occupy different frequency bands, while this solution uses OFDM frequency division multiplexing to achieve effective multiplexing of the two signals on the spectrum, greatly improving spectrum utilization.

[0087] 2. Enhance communication reliability. Since HPLC and micropower wireless communication interfere with each other, this solution allocates frequency bands that do not interfere with each other for the two signals through dynamic spectrum resource allocation, effectively avoiding interference and improving the overall communication quality.

[0088] 3. Achieve time synchronization. HPLC and micro-power wireless often have large delay differences due to different transmission mechanisms. This solution uses time synchronization and delay compensation technology to eliminate the delay difference between the two signals and ensure time synchronization of end-to-end transmission.

[0089] 4. Realize adaptive switching. In a complex channel environment, the adaptive receiving algorithm of this solution can dynamically select the communication link with better signal quality, 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 collaboration. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 A flow chart of steps performed for the modulation end;

[0092] Figure 2 A flowchart of the steps performed by the demodulator;

[0093] Figure 3 Spectrum distribution characteristics of HPLC and micro-power wireless signals;

[0094] Figure 4 Schematic diagram of channel capacity distribution of dual-mode communication system;

[0095] Figure 5 This is a comparison chart of the delay characteristics of HPLC and micro-power wireless signals. DETAILED DESCRIPTION

[0096] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0097] like Figure 1-2 As shown, it is a flow chart of the execution steps of the modulation end and the demodulation end of a HPLC and micro-power wireless dual-mode communication method provided by the present invention. The method is 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;

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

[0099] S11, collecting HPLC signals and micro-power wireless signals, and performing band-pass filtering on the HPLC signals;

[0100] S12, controlling the OFDM platform to map the HPLC signal to the first carrier frequency band of the OFDM platform, and mapping the micro-power wireless signal to the second carrier frequency band of the OFDM platform;

[0101] 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;

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

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

[0104] S16, calculating the transmission delay of HPLC communication and micro-power wireless communication according to the time synchronization signal;

[0105] S17, inputting the transmission delay into the delay compensation equation, outputting the delay compensation coefficient and the phase correction parameter, which are used to perform delay compensation for the data transmission of HPLC communication and micro-power wireless communication;

[0106] 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;

[0107] The demodulation end method includes the following steps:

[0108] S21, receiving the delay-compensated HPLC signal and the micro-power wireless signal, and measuring the signal strength;

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

[0110] S23, demodulating the signal of the main channel using an adaptive modulation and demodulation method, and switching to the backup channel when the signal quality of the main channel is lower than a preset threshold;

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

[0112] The specific implementation methods of the above steps are described in detail below:

[0113] Step S11: Collect HPLC signals and micro-power wireless signals, and perform bandpass filtering on the HPLC signals. First, collect two electrical signals transmitted by the HPLC device and the micro-power wireless device. Then, use a bandpass 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 modulate 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 spectrum utilization efficiency. Here, the first carrier frequency band is set at 3kHz to 500kHz, and the second carrier frequency band is set at 470MHz to 510MHz.

[0115] Step S13: Based on spectrum sensing technology, the first carrier frequency band and the second carrier frequency band are channel scanned to obtain the spectrum occupancy information of the HPLC channel and the micro-power wireless channel. First, a spectrum analyzer is used to perform a 60-second spectrum scan in the frequency band of 3kHz to 510MHz to record the spectrum occupancy. Then, the spectrum occupancy status of the HPLC channel and the micro-power wireless signal on each subcarrier is analyzed according to the scanning 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: Using a dynamic spectrum resource allocation model, according to the spectrum occupancy information, allocate frequency bands that do not interfere with each other for HPLC communication and micro-power wireless communication. 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 capacity of HPLC and micro-power wireless channels. The input parameters include channel bandwidth, transmit power, channel gain, noise power spectral density and interference power. The output is the capacity value of each sub-channel and the capacity change trend.

[0118] The power allocation matrix equation is used to allocate the optimal transmit power to each subchannel according to the channel status. The input parameters include 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.

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

[0120] The fusion allocation network uses a lightweight neural network to make intelligent decisions based on the output results of three matrix equations. The input is channel capacity, power allocation and spectrum 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 ReLU activation function and Dropout regularization.

[0121] Through the dynamic spectrum resource allocation model, the allocation of HPLC and micro-power wireless signals in the frequency domain can be adjusted in real time according to the current channel conditions, avoiding interference between the two communication signals and improving spectrum utilization efficiency.

[0122] Step S15: Use time-sensitive network technology to establish a unified time reference and 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 that HPLC and micro-power wireless communication achieve time synchronization and lay the foundation for delay compensation of the two signals.

[0123] Step S16: Calculate the transmission delay of HPLC communication and micro-power wireless communication according to the time synchronization signal. Using the established time reference, measure the transmission time difference of HPLC and micro-power wireless signals from the transmitter to the receiver to obtain the actual transmission delay 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 of delay compensation.

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

[0125]

[0126] Among them, 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 lth 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 qth harmonic component, f q is the frequency of the qth harmonic component.

[0128] The compensation coefficient and phase correction parameters are calculated through the delay compensation equation and applied to the data modulation of HPLC and micro-power wireless signals, which can effectively suppress the coherent interference caused by the delay difference and improve the communication quality.

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

[0130] The specific implementation of the demodulation end is introduced below:

[0131] Step S21: Receive the HPLC signal and micro-power wireless signal after delay compensation, and measure the signal strength. First, the receiving end obtains the HPLC and micro-power wireless signals from the power line and the wireless channel. Then, the power detection circuit is used 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 result, the communication channel with better signal quality is selected as the main channel, and the other channel is selected as the backup channel. Specifically, according to the measurement result of step S21, the received power of the HPLC channel and the micro-power wireless channel is compared, and the channel with better signal quality is selected as the main channel, and the other channel is selected as the backup channel. The purpose of this step is to achieve adaptive switching of the communication link to ensure that the system can reliably transmit data in a complex channel environment.

[0133] Step S23: Adopt the 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, the signal of the main channel is demodulated by the adaptive OFDM demodulation algorithm. At the same time, the signal quality of the main channel is continuously monitored. When the quality index (such as signal-to-noise ratio, bit error rate, etc.) is lower than the preset threshold, it automatically switches to the backup channel for demodulation. The preset channel quality threshold Q th The purpose of this step is to dynamically select the best demodulation path according to the current channel status to improve the reliability of communication.

[0134] Step S24: channel decoding and data recovery are performed on the demodulated data to complete the reception of dual-mode communication data. Specifically, channel coding and decoding are first performed on the demodulated digital signal to remove the error introduced by the channel. Then, data recovery is performed 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 realize the coordinated transmission of HPLC and micro-power wireless communication through key technologies such as spectrum sensing, dynamic resource allocation, and delay compensation, thereby 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 methods ensure the efficient collaborative work of the dual-mode communication system in a complex channel environment.

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

[0137] Specifically, firstly, the orthogonal frequency division multiplexing (OFDM) technology is used 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, frequency band resources that do not interfere with each other are dynamically allocated to the two signals to improve spectrum utilization. At the same time, through time synchronization and delay compensation, the coherent interference caused by the difference in transmission delay is suppressed to ensure high-quality transmission of the two signals. At the demodulation end, an adaptive receiving algorithm is used to dynamically select the best demodulation path according to the current channel conditions to further improve communication reliability.

[0138] The key innovations of this technical solution are:

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

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

[0141] 3. Use delay compensation technology. In view of the delay difference caused by different transmission mechanisms of HPLC and micro-power wireless signals, a delay compensation equation is proposed to effectively suppress coherent interference and ensure the time domain synchronization of the two signals.

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

[0143] In general, 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 principles of the present invention include:

[0145] 1. Spectrum Sharing:

[0146] Aiming at the problem that HPLC and micro-power wireless communication occupy different frequency bands, the present invention uses OFDM technology to realize the sharing of the two communication signals on the spectrum. OFDM is an efficient multi-carrier modulation technology, which divides the broadband signal into multiple orthogonal subcarriers, and each subcarrier is modulated at a lower symbol rate. This not only improves the spectrum utilization efficiency, but also effectively suppresses 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 rationally 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 the different transmission mechanisms, HPLC and micropower wireless communication often have large delay differences, which can cause coherent interference between the two signals at the receiving end, reducing the communication quality.

[0150] To this end, 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 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 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. In order to ensure the reliability of communication, the present invention adopts an adaptive receiving algorithm at the receiving end.

[0153] Specifically, the receiving end will continuously monitor the receiving power and bit error rate of the two signals, and dynamically select the communication link with better signal quality as the main channel according to the preset channel quality indicators. 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] A specific embodiment 1 of the present invention is provided below. The specific implementation of each step in the embodiment 1 is described in detail as follows: Step S11 specifically includes:

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

[0156] Then, the HPLC signal is filtered using a bandpass filter. Assume that the filter transfer function is H(f) and the cutoff frequency is f c , where f c The value range of is [3kHz, 500kHz]. 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 OFDM modulation and demodulation platform. Assume that the number of subcarriers is N, the carrier spacing is Δf, and the symbol period is T s .

[0161] Then, the filtered HPLC signal Modulate to the first carrier frequency band of the OFDM platform. The center frequency range of the first carrier frequency band is [3kHz, 500kHz], and the bandwidth is B1. wireless (t) modulate 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 B2.

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

[0163]

[0164] in, represents discrete Fourier transform, f1 and f2 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 this is to achieve frequency reuse of two communication signals and improve spectrum utilization efficiency.

[0166] The step S13 specifically includes:

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

[0168] Then, based on the obtained spectrum information, the spectrum occupancy status of the HPLC signal and the micro-power wireless signal on each subcarrier is analyzed. The spectrum occupancy index U can be defined as HPLC (k, t) and U wireless (k, t), where k represents the kth subcarrier.

[0169]

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

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

[0172] The step S14 specifically includes:

[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 of the ith subchannel at time j (bit / s), B i，j is the bandwidth of the ith subchannel at time j (Hz), P i，j is the transmission power (W), H i，j is the channel gain, N0 is the Gaussian white noise power spectral density (W / Hz), Ii，j is the interference power (W), α, β, γ are unknown coefficients, and t is the time variable (s). This equation is used to calculate the potential data transmission capacity of HPLC and micro-power wireless channels.

[0177] Power allocation matrix equation:

[0178]

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

[0180] Spectral efficiency matrix equation:

[0181]

[0182] Among them, η s，t is the spectral efficiency at time t (bit / s / Hz), R n，t is the data rate of the nth subcarrier at time t (bit / s), B n is the bandwidth of the nth subcarrier (Hz), p m is the bit error rate of the mth subcarrier, μ, ω are weight coefficients, and f i is the center frequency of the ith subcarrier (Hz). This equation is used to evaluate the utilization efficiency of spectrum resources.

[0183] The fusion allocation network uses a lightweight neural network. The input is the output of three matrix equations (channel capacity, power allocation, and spectrum efficiency), and the output is the optimal frequency band allocation scheme for 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 ReLU activation function and Dropout regularization.

[0184] Through the dynamic spectrum resource allocation model, the allocation of HPLC and micro-power wireless signals in the frequency domain can be adjusted in real time according to the current channel conditions, avoiding interference between the two communication signals and improving spectrum utilization efficiency.

[0185] The step S15 specifically includes:

[0186] Deploy precision clock synchronization devices at the modulation and demodulation ends, and use time-sensitive network technology to establish a unified time reference at both ends. The time reference is t b (t), where t is the current time.

[0187] Then, a time synchronization signal t is generated according to the time reference. s (t), can be expressed as:

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

[0189] The purpose of this step is to ensure that HPLC and micropower wireless communication are time synchronized, laying the foundation for subsequent delay compensation.

[0190] The step S16 specifically includes:

[0191] Using the established time base t b (t), measure the transmission delay of HPLC signal and micro-power wireless signal from the transmitter to the receiver. Define the transmission delay of HPLC signal as τ HPLC , the transmission delay of micro-power wireless signal is τ wireless .

[0192]

[0193] in, are the emission times of HPLC and micro-power wireless signals, 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 of delay compensation.

[0195] The step S17 specifically includes:

[0196] The delay compensation coefficient and phase correction parameter are calculated 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 lth path (s), 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 qth harmonic component, f qis the frequency of the qth harmonic component (Hz).

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

[0200] The step S18 specifically includes:

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

[0202]

[0203] Among them, X HPLC (k) and X wireless (k) are the frequency domain signals of HPLC and micro-power wireless signals on the kth subcarrier, f1 and f2 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 modulated two-way signals are transmitted through power lines and wireless channels. The purpose of this step is to achieve frequency division multiplexing transmission of HPLC and micro-power wireless signals, suppress interference caused by delay differences, and ensure high-quality transmission of the two signals.

[0205] The step S21 specifically includes:

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

[0207] Then, the power detection circuit is used to measure and record the received power of the two signals. For the HPLC signal, its received power is recorded as P HPLC ; For micro-power wireless signals, 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 step S22 specifically includes:

[0210] According to the measurement result of step S21, the received power P of the HPLC channel and the micro-power wireless channel are compared. HPLC and P wirelessSelect the channel with better signal quality (i.e., the channel with higher receiving power) as the main channel, and the other channel as the backup channel. The receiving power of the main channel is P main , the receiving power of the backup channel is P backup .

[0211]

[0212] The purpose of this step is to achieve adaptive switching of communication links to ensure that the system can reliably transmit data in complex channel environments.

[0213] The step S23 specifically includes:

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

[0215] Q main =X5·SNR main , (1-BER main ) 2 ;

[0216] Q th =15dB;

[0217] Among them, SNR main =P main / N0 is the signal-to-noise ratio of the main channel, χ5 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 based on the current channel status to improve the reliability of communication.

[0219] The step S24 specifically includes:

[0220] First, the demodulated digital signal is channel-encoded and decoded to remove the error introduced by the channel. The encoding and decoding operation can be recorded as and

[0221]

[0222] Then, the decoded bit stream is restored to obtain the final HPLC and micro-power wireless communication data. The restored data is recorded as and

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

[0224] In order to further understand and implement the present invention, the following is an example 2 of a specific common scenario of the present invention: A smart grid company is deploying a distribution automation system based on power line carrier communication (HPLC) and micro-power wireless communication. The system is mainly used in urban distribution networks, covering substations, distribution lines and user-side terminal equipment. In order to improve the reliability of communication and the efficiency of spectrum utilization, the company decided to adopt the HPLC and micro-power wireless dual-mode communication method proposed in the present invention. The following is its specific implementation.

[0225] System deployment:

[0226] The topology of the distribution automation system is shown in Table 1. The HPLC master station is deployed at the substation end to collect and process the operation data of the substation; the HPLC relay nodes are deployed along the distribution lines to undertake the tasks of line monitoring and fault warning; and the micro-power wireless terminal equipment is deployed on the user side to realize functions such as meter data collection and load control. The HPLC master station and the relay node are connected through power lines, and the micro-power wireless terminal communicates wirelessly with the nearest HPLC relay node. The entire system constitutes a hybrid communication network.

[0227] Table 1 Topology of distribution automation system

[0228] equipment quantity Communication HPLC Master Station 1 Power lines HPLC Relay Node 100 Power lines Micro-power wireless terminal 10000 Micropower Wireless

[0229] System parameters: When deploying the system, enterprise technicians measured and set the key parameters of HPLC and micropower wireless communication, as follows:

[0230] 1.HPLC signal parameters: center frequency range: 3kHz~500kHz; signal bandwidth: 10kHz / subchannel; transmission power: 0.1W / subchannel; channel gain: 0~40dB; noise power spectrum density: -150dBm / Hz; interference power: -80dBm;

[0231] 2. Micro-power wireless signal parameters: center frequency range: 470MHz~510MHz; signal bandwidth: 1MHz / subchannel; transmission power: 10mW / subchannel; channel gain: 0~30dB; noise power spectrum density: -160dBm / Hz; interference power: -90dBm;

[0232] 3.OFDM parameters: number of subcarriers: 256; carrier spacing: 39.0625kHz; symbol period: 25.6μs;

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

[0234] 5. Bit error rate: HPLC maximum bit error rate: 10 -4 ;Micropower wireless maximum bit error rate: 10 -5 ;

[0235] like Figure 3 The figure below shows the spectrum distribution characteristics of HPLC and micro-power wireless signals. The left figure shows the power spectrum density distribution of the HPLC signal in the range of 3kHz to 500kHz, and the right figure shows the power spectrum density distribution of the micro-power wireless signal in the range of 470MHz to 510MHz. It can be clearly seen that the separation characteristics of the two signals in the frequency domain.

[0236] By measuring and setting the above parameters, the company ensured the basic working conditions of HPLC and micro-power wireless communication. Next, for the specific implementation of the present invention, the company's technical personnel implemented the following steps:

[0237] Step S11: Signal acquisition and filtering

[0238] First, the HPLC master station and the micro-power wireless terminal device collect the original communication signals from the power line and the wireless channel respectively. For the HPLC signal, due to its narrow bandwidth, it only needs to be bandpass filtered in the frequency band of 3kHz to 500kHz.

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

[0240]

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

[0242] Step S12: OFDM frequency division multiplexing

[0243] The processed HPLC signal and micro-power wireless signal are mapped to different carrier frequency bands of the OFDM platform respectively.

[0244] For the HPLC signal, it is modulated to the low-frequency carrier of the OFDM platform, with a center frequency range of f1=3kHz to 500kHz, a subcarrier spacing Δf=39.0625kHz, and a total of 128 subcarriers are allocated.

[0245] For micro-power wireless signals, they are modulated to the high-frequency carrier of the OFDM platform, with a center frequency range of f2 = 470 MHz to 510 MHz. The subcarrier spacing is still Δf = 39.0625 kHz, and 128 subcarriers are allocated.

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

[0247] Step S13: Spectrum scanning and analysis

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

[0249] The HPLC master station and the micro-power wireless terminal equipment both use a spectrum analyzer to perform a 60-second spectrum scan in the frequency band from 3kHz to 510MHz and record the spectrum power density P(f, t). Based on the scan results, the spectrum occupancy index U of the HPLC signal and the micro-power wireless signal on each subcarrier is calculated respectively. HPLC (k, t) and U wireless (k, t).

[0250]

[0251] Among them, P th is the power detection threshold, which is -90dBm. 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 adopts a dynamic spectrum resource allocation model to dynamically allocate subcarriers of HPLC and micro-power wireless signals.

[0254] First, the channel capacity matrix equation is used to calculate the potential data transmission capacity of each subchannel:

[0255]

[0256] Among them, C i，j is the channel capacity of the ith subchannel at time j (bit / s), B i，j is the bandwidth (10kHz), P i，j is the transmitting power (0.1W), H i，j is the channel gain (0~40dB), N0 is the noise power spectral density (-150dBm / Hz), I i，j is the interference power (-80dBm).

[0257] Then, the power allocation matrix equation is used to allocate the optimal transmit power to each subchannel:

[0258]

[0259] Among them, λ is the Lagrange multiplier, N k is the noise power of the kth subchannel, h k is the channel response, θ k is the phase angle.

[0260] The spectrum efficiency matrix equation is then used to evaluate the utilization efficiency of spectrum resources:

[0261]

[0262] Among them, η s，t is the spectral efficiency at time t (bit / s / Hz), R n，t is the data rate of the nth subcarrier (bit / s), p m is the bit error rate of the mth subcarrier.

[0263] Finally, the fusion allocation network combines the results of the above three matrix equations and outputs the optimal allocation scheme of HPLC and micro-power wireless signals in the frequency domain, such as Figure 4 The figure shows the channel capacity distribution diagram 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 color depth represents the size of the channel capacity. Through this figure, we can intuitively see the relationship between the system capacity and the channel gain and signal-to-noise ratio.

[0264] This dynamic spectrum resource allocation mechanism can ensure that HPLC and micro-power wireless signals do not interfere with each other in the spectrum, thereby improving the overall spectrum utilization efficiency.

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

[0266] In order to suppress the coherent interference between HPLC and micro-power wireless signals due to the difference in transmission delay, it is necessary to achieve time synchronization of the two signals.

[0267] The HPLC master station and micro-power wireless terminal equipment are equipped with precise clock synchronization devices, and a unified time reference is established through time-sensitive network technology. b Then, based on the time reference, the actual transmission delay of the HPLC signal and the micro-power wireless signal are measured respectively:

[0268]

[0269] in, are the emission times of HPLC and micro-power wireless signals, The receiving time respectively.

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

[0271] Step S17: Delay compensation

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

[0273] Use the delay compensation equation:

[0274]

[0275] Among them, τ l is the delay of the lth transmission path, A q and f q are the amplitude and frequency of the qth harmonic component respectively.

[0276] Applying the calculated delay compensation coefficient to the OFDM modulation process of 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 perform OFDM modulation on the delay-compensated HPLC signal and the micro-power wireless signal, respectively, 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 micro-power wireless signal is:

[0281]

[0282] Among them, X HPLC (k) and X wireless (k) are the frequency domain signals of HPLC and micropower wireless signal on the kth subcarrier, σ HPLC and σ wirelessis the phase correction parameter, and p(t) is the OFDM symbol pulse.

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

[0284] Receiver processing:

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

[0286] First, measure the received power P of the two signals HPLC and P wireless , select the channel with better signal quality as the main channel and the other as the backup channel.

[0287]

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

[0289] Finally, the demodulated digital signal is channel coded and decoded to remove the error introduced by the channel and complete the data recovery to form the final HPLC and micro-power wireless communication data.

[0290] System Verification:

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

[0292] The trial operation results show that the system has significantly improved spectrum utilization efficiency, communication reliability and latency performance:

[0293] 1. Spectrum utilization efficiency:

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

[0295] 2. Communication reliability:

[0296] In complex power line and wireless channel environments, the system's end-to-end communication interruption probability is reduced by 45%. Dynamic spectrum resource allocation and adaptive receiving switching mechanisms effectively cope with the impact of channel changes and ensure communication reliability.

[0297] 3. Latency performance:

[0298] The end-to-end delay difference between HPLC and micro-power wireless signals is reduced to less than 5ms, which is a significant improvement over the 10ms difference in traditional solutions. The application of time synchronization and delay compensation technology ensures a high degree of coordination between the two signals in the time domain.

[0299] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by 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, select 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.

2. A HPLC and micro-power wireless dual-mode communication method according to claim 1, characterized in that: 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.

3. A HPLC and micro-power wireless dual-mode communication method according to claim 2, characterized in that: The channel capacity matrix equation is used to calculate the potential data transmission capacity of HPLC and micro-power wireless channels. The input is 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.

4. A HPLC and micro-power wireless dual-mode communication method according to claim 3, characterized in that: 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 the number of subchannels. The output is the optimal power allocation scheme that meets the total power constraint.

5. A HPLC and micro-power wireless dual-mode communication method according to claim 4, characterized in that: 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 entire system.

6. A HPLC and micro-power wireless dual-mode communication method according to claim 5, characterized in that: 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 scheme and spectrum efficiency of the three equations, and the output is the optimal frequency band allocation scheme 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. ReLU activation function and Dropout regularization are used.

7. A HPLC and micro-power wireless dual-mode communication method according to claim 6, 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.

8. The HPLC and micro-power wireless dual-mode communication method according to claim 5, characterized in that: The channel capacity matrix equation is specifically expressed as follows: In the formula, C i，j is the channel capacity of the ith subchannel at time j (bit / s), B i，j is the bandwidth of the ith subchannel at time j (Hz), P i，j is the transmission power (W), H i，j is the channel gain, N0 is the Gaussian white noise power spectral density (W / Hz), I i，j is the interference power (W), α, β, γ are unknown coefficients, and t is the time variable (s).

9. A HPLC and micro-power wireless dual-mode communication method according to claim 6, characterized in that: The power allocation matrix equation is specifically expressed as follows: Where P opt is the optimal power allocation value (W), λ is the Lagrange multiplier, N k is the noise power of the kth subchannel (W), h k is the channel response of the kth subchannel, θ k is the phase angle (rad), δ is the correction coefficient, K is the total number of subchannels, (x) + =max(0,x).

10. A HPLC and micro-power wireless dual-mode communication method according to claim 7, characterized in that: The spectrum efficiency matrix equation is specifically expressed as follows: Where η s，t is the spectral efficiency at time t (bit / s / Hz), R n，t is the data rate of the nth subcarrier at time t (bit / s), B n is the bandwidth of the nth subcarrier (Hz), p m is the bit error rate of the mth subcarrier, μ, ω are weight coefficients, and f i is the center frequency of the i-th subcarrier (Hz).

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