Application Of Variable Step Size Adaptive Filtering In Power Line Communication Denoising

Power Line Communication(PLC)technology is favored by people because of its low cost and convenient operation.However,there is a lot of noise in the PLC channel,and the most serious interference is background noise and impulse noise,which seriously reduces communication.Reliability.Therefore,it is necessary to study the characteristics of the PLC system noise and the denoising algorithm.The paper first introduces the classification and measurement methods of noise in the PLC channel,and models and simulates it.According to the correlation characteristics of three-phase power line noise,this paper uses adaptive filtering algorithm.For the fixed step size minimum mean square error(LMS)algorithm,there is a contradiction between convergence speed and steady state error.Three typical variable step size LMS algorithms based on Sigmoid function are used for PLC denoising.In the case of low signal to noise ratio,the denoising effect is not obvious.Therefore,this paper proposes an LMS algorithm that uses the correlation between the input signal and the error to correct the step size.Through the Matlab simulation comparison,in the low SNR PLC system,the improved variable step size LMS algorithm is better than the Sigmoid function based variable step size LMS algorithm.However,as the impulse noise intensity increases,the filtering effect of the improved variable step size LMS algorithm is not ideal,and the algorithm needs further improvement.Aiming at the shortage of improved variable step size LMS algorithm in time domain high-intensity pulse PLC denoising,a wavelet variable step size adaptive filtering algorithm is proposed.The input signal is first subjected to wavelet transform,and then the modified variable step size LMS algorithm proposed in this paper is used to perform matlab denoising simulation.The simulation results show that the improved LMS algorithm based on wavelet transform is suitable for high-intensity pulse PLC denoising,which provides a new way for the reliable implementation of PLC technology.Figure [56] table [8] reference [71].