Low-voltage Power Lines For High-speed Data Communications

This paper mainly researches the application of OFDM (Orthogonal Frequency Division Multiplexing) in the high-speed low voltage power line data communication, and gives a scheme of accessing Internet.Firstly this paper detailed discusses the statistical feature of the low voltage power line channel, analyzes frequency select fading and inter symbol interference caused by the multi-path transmission and gives a channel simulation mode of low voltage power line. Then introduces the principle of OFDM and discusses the realizing scheme, analyzes the performance of overcoming inter symbol interference of OFDM, and gives an OFDM system for high-speed low voltage power line communication. Later to the heavy ISI of low voltage power line, the paper introduces guard interval , cycle prefix(CP), combination algorithm of CP and self-adaptive equalization under the basis of simulation. To resolve the problem of system synchronization, the paper gives a maximum likelihood estimation algorithm which can resolves synchronization of symbol frame and carrier offset in OFDM system. To improve the performance of the OFDM system, this paper discusses channel encoding, interleaving and digital modulating, simulated analyzes OFDM system performance using Matlab under different channel code, interleaving, digital modulating and length of Discrete Fourier Transform. Last this paper discusses the parameter of OFDM base band system for hardware development, analyzes the hardware feasibility of OFDM base band system.