Design Of Visual Simulation Platform For Low-voltage Power-line Communication System Based On OFDM

Power Line Communication(PLC) is one data/voice transmission method by making use of power line as a communication media. The characteristics such as no wiring, wide coverage and convenient connections make it have huge potential applications. With the development of network technology, business on broadband PLC and network transmission speeds are demanded higher and higher. One of the key problems is how to improve the transmission performance on power line, realize the high-speed, reliable and long-distance communication. The thesis mainly discusses this issue and designs a system model for simulation analysis.First of all, the thesis analyzes in great details characteristics of the power-line channel. Then, the noise scenarios of the power line and its classification discussed, together with the simulation analysis to the major noise models. Secondly, the concept, advantage and anti-intererence principle of Orthogonal Frequency Division Multiplexing(OFDM) technology are introduced in detail, which is the key technology of PLC. And the necessity and feasibility for daopting OFDM technology in PLC system are presented further. Third, by using MATLAB6.5 as simulation tools, a PLC system model based on OFDM is set up and the extensive simulations are carried out based on this platform. Finally, a graphical user interface(GUI) is designed to control the simulation process by setting parameters in it, which realizes the visualization of system simulation. The simulation analysis and results show that, in the medium like power line, using OFDM modulation technology can effectively overcome the frequency-selective fading characteristics in power line channel transmission, and enhance the system performance of anti-multipath interference. Through simulation and analysis, we know that adding channel code can improve the whole performance of PLC system. In addition, the sub-carrier modulation in different ways (such as, QPSK, DQPSK, QAM etc.) have different influence on the system BER performance, and against different channel SNR, the effect on BER performance is also different.The platform of low-voltage PLC system has open function for continuous expansion and improvement, which provides a basis for optimizing system parameters to enhance anti-interference capability, and facilitates the continuation of research work.