Research On The Communication Technology Of LDPC-OWDM In Low-Voltage Power Line

Recently, with the continuous development of communication technology, it has focused more and more attention to transmit all kinds of data service by using low-voltage power line. OFDM technology, which can satisfiy the demond of high speed transmission, is considered to be one of the key technology of communication in low-voltage power line. However, because of the extremely lousy channel environment of low-voltage power line, the advanced channel coding method, LDPC code, has been thought highly. Because OFDM technology exits something to be improved, for example, added cyclic prefix make OFDM reduce the bandwidth utilization and possess more higher Peak-to-Average Power and so on, many scholar continuely study multi-carrier communication system, which is new and has good function. Wavelet transform is stronger than Fourier transform in the area of analyzing signal's ability, so more and more people begin to study it. But, the study on wavelet transform is just on its beginning period and a lot of questions need to be solved.The improved multi-carrier communication system LDPC-OWDM is deeply researched analyzed and simulated in this paper. The main contents are below:(1) Analyzed the basic model of communication system, and deeply analyzed the channel model of communication system. (2) Established a kind of three layers topological structure in low-voltage power line and proposed an impendance measuring method in the channel of low-voltage power line. Used this kind of method to measure the impendance and then anysized them. (3) For communication in low-voltage power line, deeply studied advanced channel coding technology, LDPC code. Wtited its coding and decoding program and anasyzed its predominant anti-noise function. (4) Studied the theory of OFDM technology and its application in low-voltage power line to realize dependable data transmission. (5) Deeply studied wavelet transform and used it to replace FFT in the system of LDPC-OWDM in order to improve the systemic function. (6) Simulated and ayalyzed the function of LDPC-OFDM and LDPC-OWDM system in the channel with different interfence noise, which formed the foundation for the optimization of the system. (8) Because power system mass fault recording data had a big data volume and high error rate when transmitting in low-voltage power line, used both source and channel coding Coded-OWDM system to realize reliable transmission.