| Power Line Communication (PLC) is currently a very promising Internetbroadband communication access technology. It is an advanced communicationmode which uses common household power lines for data transmission andinformation exchange. Orthogonal Frequency Division Multiplexing (OFDM) isthe preferred demodulation technology to realize broadband power linecommunication, which can anti-multipath delay, frequency selective fading andhas high spectrum efficiency to achieve a high-speed, reliable datacommunication. Channel estimation is one of the key technologies of OFDM,whose performance stand or fall has a direct impact on the reliability and validityof the entire communication system.Firstly, this dissertation introduces the domestic and foreign developmentstate of low voltage PLC, analyzes the basic principles and characteristics ofOFDM, and expounds the performance advantages of OFDM in power linecommunication. Then the channel characteristics of input impedancecharacteristics, attenuation characteristics and noise characteristics of power linehave been explained, and low-voltage power line channel model has beenconstructed in this dissertation. Next, analyze several kinds of currently channelestimation algorithm used in power line communication, based on the traditionalDiscrete Fourier Transform (DFT) channel estimation algorithm is improved.There is a decision threshold set within the cyclic prefix of traditional DFTchannel estimation which made the improvement of DFT channel estimationalgorithm come true. Through the threshold, judge the CIR estimation and furthereliminates the influence of noise in the cyclic prefix in order to improve theaccuracy of channel estimation.Finally, use the MATLAB software to verify the simulation of the improved algorithm. Through the comparison of bit error rate, it can be seen that when theSNR is greater than5dB, under the same BER condition, SNR averageperformance improvement of1dB, shows that the algorithm has a goodperformance. |
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