电力线小波变换正交频分复用通信系统分析

Analysis of Wavelet Transform-Based OFDM Power Line Communications System

为保证复杂信道环境下电力载波通信可靠性,将正交小波变换应用于正交频分复用(OFDM)中,形成离散小波变换(DWT)OFDM系统,将其应用于电力载波通信(PLC)中以提高通信性能。在DWT-OFDM系统中,通过不同小波基性能对比,选出最优bior6.8双正交小波基,在实测电力线信道环境下对DWT-OFDM系统进行仿真分析,在保证可靠性的前提下,通过合理减少循环前缀,优化传输效率和降低峰均比。结果表明:双正交小波变换具有紧支撑性,满足近似对称性,可获得更高效的信号重构。在10-3级时,性能提升了5dB左右。正交小波在保证可靠性的同时,通信效率由40%提高至54%左右,峰均比由11dB降低至9dB。基于DWT-OFDM的电力线通信消除了频偏和相位噪声影响,可靠性优于快速傅里叶变换(FFT)OFDM系统。

In order to ensure the reliability of power carrier communication in a complex channel environment,orthogonal wavelet transform is applied to orthogonal frequency division multiplexing(OFDM)to form a discrete wavelet transform(DWT-OFDM)system,which is used in power carrier communication to improve communication performance.In the DWT-OFDM system,the optimal bior6.8 biorthogonal wavelet base is selected by comparing the performance of different wavelet bases,and the DWT-OFDM system is simulated and analyzed under the measured power line channel environment.By reasonably reducing the cyclic prefix,the transmission efficiency is optimized and the peak-to-average ratio is reduced.The results show that the biorthogonal wavelet transform has tight support and satisfies approximate symmetry,and can obtain more efficient signal reconstruction.At the level of 10-3,the performance is improved by about 5 dB.The orthogonal wavelet guarantees reliability while improving communication efficiency from 40%to about 54%and reducing the peak-to-average ratio from 11 dB to 9 dB.power line communication based on DWT-OFDM eliminates the effects of frequency offset and phase noise,and its reliability is better than fast fourier transform(FFT)-OFDM system.