The Study And Optimization Of Power Line Communication Channel Modeling And Noise Modeling

Power line communication(PLC) technology was originated in the early1920s, and thus it has nearly90years of history.has made tremendous progress. The research of the PLC technology in China started at the end of the last century, which was much later than that of western countries. Compared to the network of computer, the communication network and the broadcasting network, the power line network has unique advantages on coverage since it has a wide distribution based on existing power distribution line. Therefore, the PLC technology has become a hot research topic especially in "the last1km" of broadband Internet as well as the digital in-home distribution network in recent years.In fact, mainly because the initial role of the power line network is power transmission rather than communications, the power line network is a challenging transmission environment for the high data rate of data transmission. Firstly, after tens of meters transmission on the copper wire, the transmission signal will emerge a strong attenuation. And in the case of the topology network, tens of meters transmission, the signal will be the multipath transmission which will result in frequency selective fading. Secondly, different types of electronic noise in the power line medium will cause signal distortion. Finally, the transimission signal will be subject to fluctuation of the varied channel characteristics because of the different locations as well as household appliances accessed to network through many existing power outlets at home. For those reasons, it is necessary to study the power line communication channel and noise deeply.The article mainly focus on the research of power line communication channel modeling. On the basis of a large number of references, a PN sequence correlation method is proposed to obtain power line transfer function. And then, a modeling measurement is carried out through the method in power line channel both at laboratories and actual environment, and got the150m/250m/350m length laboratories channel transfer function curve and50m/100m/150m length actual channel transfer function cureve. At last, a vector network analyizer is used to verify the accuracy of the method. The results turned out the PN sequence correlation method can acqurire the accurate channel transfer function curve.In addition, a simple telemedicine experiment was also studied based on the power line channel. The experiment shows that after short length power line transmission of the acquisition signal, at the receiving port the signal can restored well.