Noise Chaeacteristics Analysis And Modeling Research In Power Line Channel

The power line communication is a communication method in using power line as a communication channel for data transmission. Its advantage is distributed widely and easy to connection, etc.; it’s the country’s major research objectives in the future. The power line channel noise is the main factor in affecting the power line communication. Based on power line communication channel characteristics, this paper analysis the noise characteristic of the indoor and outdoor and establish the noise model of the power line channel; Introduced OFDM modulation technique and discuss the power line communication applications, the main work as follows:Elaborate power line communications technology background, research status and the affect of power line channel noise.Analysis the power line’s input impedance characteristic, the attenuation characteristics. Analyzed in detail the noise characteristics and classification. At present, the power line channel mainly includes colored background noise, narrowband noise and impulse noise (frequency synchronization, frequency asynchronous and random impulse noise). The narrow band noise, industrial-frequency periodic noise and impulse noise model are established. Using matlab software simulates the model.The noise acquisition is used to collect indoor and outdoor noise data. In order to investigate the noise statistic characteristics of the PLC channel based on the measuring noise data, this paper analyzes the low voltage power line noise characteristics in time and frequency domain respectively. And the narrow band noise and impulse noise model are established. After optimization to the noise model by using the measuring data, the noise statistic characteristics of the PLC channel are computed and simulated. The simulation results show that the established noise model is consistence with the actual measuring noise in time domain waveform, and it is smaller error in frequency domain, which validate the effectiveness of the established model.Elaborate the application of the carrier technology of OFDM in power line communication. OFDM’s advantage includes anti-noise performance, anti-fading performance and anti-multipath interference. Studies have shown that OFDM is suitable for achieve high-speed data transmission in power line channel environments.