Implementation Study Of PLC Narrow Band Width Key Technology Based On OFDM

PLC (Power Line Communication) is a data transmission method using the power line as the communication media. The wide coverage, the low cost and the convenient access of powerline network grant itself a unique advantaged technology to access network. But the noises, the frequency selective attenuation and the multi-path propagation inherently existed in the power line make it difficult to achieve good performance.The report first introduces the background of power line communication, the technological advantages and good application prospects. Then, it describes the concept of OFDM in detail which is a key technology of PHY layer in powerline communication and considered as an ideal modulation technology that can effectively reduce a variety of adverse effects on power line channel. With the study of PLC channel, we build a powerline OFDM communication system model and carry out the relevant studies about timing synchronization including S&C correlation algorithm, matched filter algorithm and improved matched filter algorithm. We compare the performances of these timing synchronization methods, and find a proper one which is suitable for power line communication.Finally we test the communication system using adaptive modulation algorithm and dynamic subcarrier allocation algorithm under different power line channel conditions. Simulation results demonstrate that these two algorithms can improve the transmission rate of the entire system when meeting the requirements of a certain bit error rate and guarantee the communication stability of the low-voltage power line communication system when the power line channel conditions change frequently.