窄带电力线通信中对抗突发脉冲的信道估计方法研究

Abstract

在窄带电力线通信系统中，时域突发脉冲是影响性能的最主要干扰之一。该系统中采用OFDM多载波方式，接收机在频域进行处理时，时域突发脉冲在FFT之后会扩展到整个频段上，进而严重影响系统的性能。因此，接收端需要采取有效的干扰消除机制。置零算法因其操作简单被广泛应用，然而，这种非线性操作会引入载波间干扰(ICI)，导致系统信道估计准确性降低和BER性能变差。本文在此种条件下提出一种新的信道估计方法，迭代消除信道估计中的ICI部分，来降低突发脉冲的影响。仿真结果表明本文提出的改进方案可以有效提高信道估计的准确性，并使系统性能相应提升。 The additive impulsive noise is one of the serious interferences in narrow band power line communication (NB-PLC). With the widely used OFDM (Orthogonal Frequency Division Multiplexing) technology, the influence of the impulsive noise can spread to every subcarrier after DFT in the receiver, which degrades the communication per- formance seriously. Therefore, a simple and effective interference cancelation scheme is required, for example, blanking nonlinearity has been widely used to suppress the impulsive noise due to its convenient operation. However, the nonli- near operation introduces inter-carrier interference (ICI), resulting in degradation in both system performance and the precision of channel estimation. In this paper, a new channel estimation method for OFDM transmission is proposed to reduce the affection of impulsive noise in power line channel, where the ICI part in the estimated channel response function can be iteratively cancelled. The simulation results show that the proposed method can improve the precision of channel estimation and reduce the bit error ratio (BER) significantly at the same time.