The Design And Implementation Of Home Power Line Physical Layer Communication System

Home power line communication system exploits power line to the transmission of data. It has many superiorities like large numbers of users, widely distribution and no rewiring. Home PLC system can be used as an effective means of home network communication. However, the PLC channel exists multi-path fading effects and has many kinds of channel noises. Many researches focus on improving the quality of home broadband PLC under high data rate.Low Destiny Darity Dheck(LDPC) codes is a kind of linear block codes which is the most closest to the Shannon limit. LDPC codes has been widely studied in recent years because of its powerful error-correcting capability and low decoding complexity. Orthogonal Modulation Division Multiplexing(OFDM) segments a channel to many subchannels for the efficient use of bandwidth and overcoming the frequency selective fading. OFDM is currently one of key technologies for high-speed broadband communications. Therefore, design of a PLC system with LDPC-OFDM has a practical significance.ITU association established a next generation unified home network standard Ghn capable of operating over coaxial cables, phone lines and power lines in 2009. Ghn standard uses multi-carrier scheme based on windowed OFDM and a single advanced Forward Error Correction (FEC) scheme based on LDPC.The thesis designs a PHY communication system under PLC channel basing on the studies ITU Ghn PHY communication system. The system includes LDPC encoder, OFDM modulator, LDPC decoder and OFDM demodulator. LDPC decoder should provide good performance of error correction in high-speed communication.In OFDM demodulator, the receiving signals need to do exact symbols synchronization. The demodulator uses preamble sequences to calculate channel estimation.At last, the thesis tests the PLC PHY communication system in simulation PLC channel. The results are provided eventually. The results show that the LDPC-OFDM system can provide high-speed and high level quality.