Power Line Channel Noise Suppression Method Research Based On The Pretreatment

The power line communication network is an infrastructure that ensures the safe and stable operation of the power system.Power line communication technology uses existing power lines for communication.Because no need to re lay the communication line and low economic cost,power line communication has been paid much attention.However,there is a lot of noise in the power line communication channel,which seriously affects the reliability of power line communicati on.Therefore,in order to ensure the quality of communication,it is necessary to analyze the noise characteristics of the power line communication channel and study the noise suppression.This paper studies the digital communication system based on OFDM technology,analyzes related technologies,establishes relevant noise model,and deeply studies noise suppression based on preprocessing.The main work done in this paper is :The noise components in power line communication are analyzed.The background noise modeling is modeled based on the traditional noise modeling and measured power line noise.The model of the impulse noise is built on the basis of the Bernoulli-Gaussion impulse noise model through the parameter adjustment method.In the simulation analysis of modeling,the noise model is compared with the actual data in the time domain and frequency domain,and the duration and amplitude distribution curve of the impulse noise are analyzed.The algorithm of reducing the peak to average power ratio is st udied,and it is used as a preprocessing part of noise suppression.In this paper,the peak to average ratio distribution of OFDM signals is analyzed,and then several algorithms for reducing PARP are studied,and the complementary cumulative distribution function expression of the SLM algorithm is derived.Finally,the algorithm of clipping,SLM and PTS is simulated,and the limitation of the clipping algorithm is analyzed.The complementary cumulative distribution curve of the algorithm is compared.The nonlinear noise suppression method based on preprocessing is studied.First,two nonlinear noise suppression methods of blanking and clipping are introduced,and the SNR gain of the two suppression algorithms is deduced in detail.According to the cumulative distribution function of SLM algorithm,the probability density function of noise cancellation error is derived.Finally,the performance curves of the pre processed and non pre processed nonlinear noise suppression algorithms are compared,and the improvement of the noise suppression performance of the pre processed nonlinear noise suppression is verified.The wavelet noise suppression based on preprocessing is studied.Firstly,the wavelet transform is briefly introduced,the steps and principles of wav elet denoising are analyzed,and the commonly used soft threshold function and hard threshold function are introduced.In the simulation analysis,the difference of noise suppression performance of different wavelet bases and different wavelet decompositio n layers is analyzed,and the pre processing and unprocessed wavelet denoising are compared,and the pre processed wavelet denoising performance is improved obviously.