The Method Of Noise Suppression In Power Line Communication Based On Compressed Sensing

As a kind of communication method,power line communication has attracted widespread concern among researchers because it has many advantages such as wide coverage area,low installation cost and broad market prospect.However,as a medium for data transmission,power line has a bad channel environment,obvious delay effect,large noise interference and other bad factors,which seriously affect the communication quality of power line communication system.Especially the existence of impulse noise seriously interferes with the transmission of data signal.As a modulation method with high spectrum utilization,good anti-multipath effect and good anti-noise performance,OFDM multi-carrier modulation has been widely used in the research of power line communication.As an emerging data compression theory,compressed sensing breaks the traditional data sampling law and can reconstruct the original data signal without distortion from less compressed measurement data signals.This paper focuses on the noise reduction method of OFDM power line communication based on compressed sensing precisely considering the use of compressed sensing theory for data acquisition can greatly save data storage resources,and the use of OFDM modulation can improve the data transmission rate and other advantages.Firstly,this paper proposed a power line communication system model,elaborated on the basic principles of the OFDM system model,and detailed the FFT/IFFT implementation,protection interval and technology advantages and disadvantages in the key technologies.Subsequently,this paper introduced five types of noise commonly found in the channel of power line communication system,and analyzed the time/frequency domain characteristics of various types of noise and the classical impulse noise model.Secondly,this paper also introduced the theory of the compressed sensing algorithm,the construction method of the measurement matrix and the sparse representation of non-spase original signals and verified the common OMP algorithm,SP algorithm,SAMP algorithm of compression sensing and the reconstruction performance of compressed sensing algorithm after singular value optimization measurement system.Moreover,the OFDM power line impulse noise suppression method based on compressed sensing is proposed which make full use ofadvantages of compressed sensing algorithm capable of reconstructing sparse signals with high precision and combine the sparse characteristics of impulse noise.The method uses the transmitted data on the null subcarrier as the measurement signal of the compressed sensing,the partial Fourier operator as the sensing matrix,and the background noise power as the algorithm iterative error.In addition,a variable step size SAMP algorithm is proposed to reduce the iterative running time of SAMP algorithm and the reconstruction performance of the algorithm is analyzed by Matlab experiment.Finally,in order to balance the reliability and effectiveness of the data transmission in the communication system,a pre-processed compressed sensing algorithm is proposed.This method can be used in the communication system to improve the error rate of data transmission.The proposed optimized pre-processing method(OPA-SAMP)is more effective in suppressing impulse noise in the case where the probability of occurrence of impulse noise is high and the number of data subcarriers is large.