Research Of OFDM Synchronization Technology Based On PLC

In this year middle-voltage power line communication is mainly used in mediumvoltage distribution network. The characteristics of medium voltage power linecommunication are wide distribution, good infrastructure and low cost ofcharacteristics, which attract people’s attention and have received the widespreadattention. Among the modulation techniques of medium voltage power linecommunication, the orthogonal frequency division multiplexing (OFDM) can be moreeffective against the harsh conditions of power line communication，which ensurereliable and high-speed data transmission. However, OFDM technology is sensitive tosymbol timing synchronization and frequency offset error. When the OFDMsynchronization errors occur in the system will affect the reliability and effectivenessof data transmission. Therefore, the key of guaranteeing stable and reliable datatransmission is choosing the suitable method of OFDM synchronization.In response to these problems, this paper will study the OFDM symbol timingsynchronization and frequency offset estimation in medium voltage powercommunication. Firstly, the channel noise of medium voltage power linecommunication is analyzed. The noises are divided into five different classesaccording the noise source and spectrum, and then simulate these kinds noise andsynthesis them as power line channel noise. According to the channel attenuationmodel the channel of medium voltage power line.Secondly, the OFDM technology is described. The influence on OFDM system isanalyzed respectively under symbol timing synchronization error and symbol timingsynchronization error. And the influence on data transmission of the integer andfractional frequency offset also are analyzed.Finally, this thesis analyzes the existing OFDM algorithm. According theadvantages and disadvantages of the existing algorithm, this thesis put forward abetter OFDM algorithm including symbol timing estimation and frequency offsetestimation. Through the simulation of the proposed algorithm, the thesis proves theimproved algorithm has better precision and reliability.