一种正交频分复用低压电力线通信系统的信道估计与迭代均衡策略

正交频分复用(orthogonal frequency division multi- plexing，OFDM)技术在低压电力线高速通信研究和应用领域获得了广泛重视。传统的OFDM系统通过对每个符号添加大于信道响应长度的循环前缀(cyclic-prefix，CP)来消除符号间干扰，使传输效率降低。提出一种低压电力线信息符号无循环前缀的OFDM通信系统的信道估计与迭代均衡策略，该策略采用m序列作为训练序列，利用其特殊的自相关特性，在系统接收端获得信道的时域响应，进而对无循环前缀的OFDM信息符号进行迭代均衡，以消除符号间干扰。仿真实验表明，该策略可提高传输效率、增强系统的抗噪性能、获得比传统OFDM系统更低的信道估计均方误差和误码率，且具有较低的计算复杂度。

A Channel Estimation and Iterative Equalization Scheme OFDM in Low-voltage Power-line Communication System

Orthogonal frequency division multiplexing (OFDM) technique is widely attractive in low-voltage power-line high-rate communication area. Conventional OFDM systems eliminate inter-symbol interference (ISI) by inserting cyclic-prefix which is longer than channel response maximum length to each OFDM symbol. It inevitably brings decreased transmission efficiency. A channel estimation and iterative equalization scheme in OFDM low-voltage power-line communication systems with non-cyclic-prefix information signals is proposed. Adopting m-sequence as training sequence and taking use of its special autocorrelation characteristics, channel time-domain response can be obtained at the receiver. Then, ISI can be further removed through iterative equalization. Computer simulations show that the scheme proposed increases the transmission efficiency, and at the same time, can obtain lower error bit rate and mean square error of channel estimation than conventional OFDM systems with relative low complexity.