Design Of Broadband Power Line Carrier Communication System Based On OFDM

With the rapid development of Smart Grid, the study on PLC technology has become a hot, it can generate enormous economic benefits while can also promote the development of PLC technology in China at the same time. At present, the civil PLC chips mainly adopt single carrier and spread spectrum modulation technology, only suppose to the function of reading meter. Based on OFDM, PLC technology with high bandwidth efficiency, strong anti-channel capability, suitable for high-speed transmission, and anti-inter-symbol interference features, which can meet the requirements of the smart grid on reliability, safety and timeliness, it can become a core technology of the new generation PLC chip and has a wide application future. This paper focus on the research of broadband Power Line Carrier Communication System's design based on OFDM, and the main contributions are summarized as follows:1. The characteristics of the low-voltage power line channel is analyzed and the power line channel simulation model is established. Then, the basic principles and implementation process of OFDM technology is introduced, and the advantages of OFDM technology for the power line carrier communication system is clarified. According to the goals and requirements of the system, the system's parameters is computed. Considering the specificity of power line channel, a broadband power line carrier communication system was designed based on OFDM, including system parameters selection, transmitter scheme and reciver scheme.2. Power line carrier communication synchronization algorithm and channel estimation are studied based on the OFDM. The impact of synchronization offset, frequency offset and the errors of channel estimation on OFDM systems are analyzed. A synchronization algorithm based on preamble in receiver is designed. Combined with the actual situation with the system, the classical symbol synchronization algorithm, frequency synchronization and channel estimation are improved. Simulation results of MATLAB show that the improved algorithm performances can meet the design requirements of the system at low signal to noise ratio.3. The receive scheme of the data is designed based on the characteristics of the data, using ROBO interleaver can against the fading of power line channel, and the combination of OFDM and Turbo system can enhance the error correction capability of the system, so as to transmit correctly at low signal to noise ratio. Simulation results show that the design of the receiving scheme based on data load achieves the expected performance of the system.