Research On LED Control Algorithm Based On Low Voltage Power Line Carrier Communication

With the progress of science and technology and the development of society and the advancement of rural urbanization,people have higher expectations and requirements for the future smart city.About 20% of all kinds of power transmission network and communication resources are needed to be solved for LED(light emitting diode)real-time transmission and information transmission in all parts of the country.According to the requirements of application scenarios,this thesis further seeks for more optimized signal modulation and demodulation algorithm and coupling mode in the current typical equipment model of power communication,improves the anti-interference ability of power carrier communication terminal,promotes the real-time traffic monitoring system and LED visible wireless communication system in smart city.(1)Based on the research of the popular LED street lamp control system currently in use in urban construction,this thesis built a simplified LED model of general power line carrier control in the laboratory,and explores how to improve the transmission algorithm to increase the limit of data transmission and to reduce the bit error rate.In the laboratory,the process of implementing remote control of the LED street lamp monitoring system through the power line carrier to the terminal was simulated,and the improved algorithm was tested for extreme data transmission.Compared with the test results of the algorithm before the improvement,the bit error rate of the system channel after the optimization reduced from 14.8% to 10.7%,the maximum instantaneous transmission data volume that the channel could withstand had been increased from 13638 bytes to 18833 bytes.(2)This thesis studied the signal transmission process in the currently widely used OFDM(orthogonal frequency division multiplexing)system combined with the LS algorithm,MMSE algorithm,LMMSE algorithm,linear interpolation and other sub-channel anti-jamming algorithms,compared the performance of various channel estimation algorithms based on the MATLAB simulation,and proposed a method to optimize the overall anti-interference ability of the system using the Lagrangian interpolation method in the sub-carriers combined with the LS pilot channel estimation algorithm.The study showed that under different signal-to-noise ratios,the error rate of the proposed Lagrangian interpolation channel estimation algorithm was about 30% lower than that of the popular linear interpolation channel estimation algorithm.(3)In order to further verify the proposed Lagrange interpolation channel estimation algorithm on the anti-interference ability of carrier communication in the scene of remote meter reading at the end of the actual power grid channel,this thesis adopted two experimental methods: hardware test in laboratory simulation scene and hardware test in field,and used the packet loss rate in the actual power grid system to judge whether the remote meter reading result is good or not The performance index was used to test the data transmission performance,performance index and anti-interference ability of the carrier chip loaded with the optimized algorithm in various practical applications and extreme noise environments.At the same time,the equipment group using the original algorithm carrier chip was designed synchronously,so that the equipment of two groups of devices with different algorithm chips were in the same installation conditions,the same noise environment and the same transmission signal under the same time node,the data acquisition contrast test was carried out.The test result showed that the total packet loss times of the equipment group using the optimized algorithm in the laboratory environment was only 58% of the original carrier chip device group,and the total packet loss times of the equipment group using the optimized algorithm was only 77.34% of the equipment group using the original carrier chip in the actual application environment.The test results were basically consistent with the MATLAB simulation and showed that the anti-interference ability of the proposed algorithm optimized by Lagrange interpolation method for low-voltage power cable noise,especially tburst noise was greatly improved compared with the current popular channel estimation algorithms.