High-frequency Channel Characteristics Of Low Voltage Distribution Network And Communication Channel Capacity

Using the existing low voltage power line to communicate with high bit rate have been developed in the last few years. Because this technique can make the best of the resources of power line and it is convenient for installation and usage, it has caused more and more people's attention. Based on the structure of the lower voltage distribution networks in our country, the broadband noise, the attenuation characteristics, the high frequency channel model and the channel capacity are intensively studied in this paper. The noise and high frequency signal attenuation on the actual low voltage distribution networks are measured in this paper, by analysis of the result, the noises distribution and the attenuation characteristics are studied. Through the measurement, the noises characteristics of general electric devices are analyzed, the statistical expressions of the background noises are given, and the attenuation characteristics of electricity meter, air switch and indoor power line networks are given too. The low voltage distribution networks are divided into two parts according to practical usage, the indoor part and the outdoor part. The transfer function of the power line networks is figured out using the multi-path model, the transmission matrix model and the multi conductor theory. Through the compare of the measured data and the calculated data, the theoretic results are proved. The channel capacity of the indoor power line and outdoor power line are studied in the paper, and the effects on the channel capacity of some factors are presented, such as the branches of power line, the transmission distances, the loads and noises, the numerical results are presented in the paper too. After the analysis it is clear that among the factors that affect the power line channel capacity at special noise environment the transmission distance and the branches of power line are two main factors.