中压配电线通信系统脉冲噪声处理的阈值优化算法

Optimization Algorithm for Impulsive Noise Mitigation Schemes of Middle-Voltage Distribution Line Communication Systems

OFDM用于实现高速电力线通信越来越受关注。脉冲噪声是电力线信道的主要干扰之一。该文在消隐非线性输出SNR分析的基础上,提出了OFDM系统脉冲噪声处理的阈值优化算法。仿真结果显示,如果OFDM系统的子载波数足够大,则实际系统输出SNR与理论表达式可以很好吻合。对于给定的脉冲指数,存在一个最低最优阈值;不同的脉冲指数A,其最低最优阈值不同,A越小,最低最优阈值反而越大;消隐器输出SNR及其性能增益是信号脉冲噪声比(SINR)的函数:在低SINR和高SINR下,输出SNR呈线性变化,性能增益分别趋近于定值;在中间SINR下,消隐器输出SNR及其性能增益是SINR的非线性函数。本消隐非线性阈值的优化算法可以改进脉冲噪声检测算法的性能,进而大大改善OFDM系统在中压配电线脉冲噪声环境中的总体性能。

OFDM has received a considerable attention for realization of high-speed power line communications, and impulse noise is one of the main disturbances in power line. An optimization algorithm for impulsive noise mitigation in OFDM system is proposed based on the analysis of output SNR of blanking nonlinearity. Simulation results show that the proposed analysis provides very good prediction of the output SNR if the number of OFDM Subcarriers is sufficiently large. For given impulsive index （A）, there is a minimal optimum threshold. As the decrease of A, the minimal optimum threshold becomes larger. The output SNR and performance gain are functions of Signal to Impulsive Noise Ratio （SINR） respectively. Under lower and higher SINR, the output SNR changes linearly; and performance gain close to a fixed value respectively. But under middle SINR region, SNR and gain are nonlinear functions of SINR. The optimization algorithm proposed can improve the performance of impulse detection algorithm; furthermore, heighten the overall performance of the OFDM receiver in impulsive noise environment.