Research On Noise Characteristics And Channel Estimation Method Of Low Voltage Power Line Communication

Power line communication(PLC)is a communication technology that uses the existing power distribution network to transmit information.The main responsibility of the powerline system is to supply and distribute power rather than to realize communication,so compared with the system specially used for communication,the channel characteristics and noise interference of PLC reflect its own uniqueness.The multipath fading effect and random impulsive noise seriously affect the communication quality of PLC.The main research contents and achievements of this thesis are as follows:1.The channel characteristics and noise characteristics of power lines are studied.The characteristics of power line channel are analyzed,and the multipath propagation model is used to model it according to its characteristic of typical multipath effect and frequency selective fading.Based on the characteristics and causes of each noise,different modeling methods are adopted.It can be seen from the analysis and comparison that the pulse noise has the greatest interference to PLC.2.The impulsive noise suppression method based on partial transmission sequence is studied.Several typical nonlinear impulsive noise suppression technology is studied,and partial transmission sequence(PTS)scheme is introduced to improve blankingclipping scheme performance by reducing the signal peak-to-average power ratio(PAPR).By simulating and comparing the proposed method with other nonlinear techniques,it is verified that it has better pulse Noise suppression performance.Under the Signal to Noise Ratio(SNIR)between-5d B and-13 d B,the bit error rate decreases significantly.3.The maximum likelihood channel estimation scheme based on adaptive differential evolution(ADE-ML)is studied.The principle,advantages and disadvantages of several channel estimation sheme used in power lines are analyzed.To solve the problem that ML estimation is dependent on effective channel length acquisition,an improved parameter adaptive differential evolution method is introduced to obtain the channel length of ML estimation.Simulation verifies that this method has better estimation performance.Compared with RVM channel estimation,when the Mean Square Error(MSE)is 10-3,its Signal to Noise Ratio(SNR)improves by about 7d B.