Research On Adaptive Noise Suppression Technology For Power Line Communication

The low voltage power line carrier communication technology uses the existing power line as the transmission medium.It has become the mainstream communication mode between the user meter of the domestic power information collection system and the area concentrator.There are complex pulses and background noises in the power line,which become an important factor affecting the reliability of power line communication system.This paper focuses on the noise characteristics of low voltage three-phase power line and the corresponding noise suppression method,which has important theoretical and practical significance.This paper mainly completes the following contents:Firstly,the characteristics of power line noise are analyzed under the real noise environment,and drawing a conclusion that there is a strong correlation between three-phase power line noise.Based on this,a noise suppression method for power line communication based on adaptive filtering technology is proposed.And the simulation platform of QPSK modulation power line communication is established.Based on LMS,NLMS,AP and RLS four classical adaptive algorithms,the effect of power line noise suppression under different carrier frequency and different SNR is verified from the time domain waveform,spectrum diagram and bit error rate.The results show that RLS algorithm has the best noise suppression effect.And the adaptive algorithm can still play a significant role,when further considering the cross-phase coupling of communication signals.Secondly,the simulation platform of OFDM modulation power line communication is established for the 0.7-3MHz HPLC system.Based on four classical adaptive algorithms,the noise suppression of power line communication is studied from the aspects of spectrum,error location,constellation and error rate.On the whole,the noise suppression effect of the RLS algorithm under OFDM modulation is still the best.Finally,two kernel-based adaptive algorithms are introduced.The results show that the kernel-based algorithm is better than the corresponding traditional algorithm,and the cost is higher algorithm complexity and greater resource consumption.In general,the adaptive noise suppression method based on the correlation between power line phase noises can effectively reduce the bit error rate of communication,and this method has good applicability,it is not depend on the statistical characteristics of noise,and is not limited to the suppression of impulse noise.