基于信号共轭周期平稳特性的MIMO信道估计方法

A MIMO Channel Estimator Based on the Cyclostationarity of the Signal

MIMO系统中,由于各天线间干扰以及码间干扰等问题的存在,信道估计性能成为影响系统性能的决定性因素。直接利用接收信号的二阶统计特性进行信道估计是目前比较通用的方法之一。本文基于信号的二阶共轭周期平稳特性。提出了一种适用于MIMO系统的信道估计方法,该方法直接利用接收信号的共轭周期自相关函数间的关系,消除了系统的码间干扰(ISI)和信道间的互扰(CCI),分离出信道矩阵的各个元素分别加以估计。该估计算法不需要事先知道信道的准确阶数,整个估计结果不受信道阶数过估计的影响。由于一般的信号不具有共轭周期平稳特性,因而本文同时还提出了一种在MIMO系统中构造和处理二阶共轭周期平稳特性信号的方法。本文最后给出的仿真结果显示所提的估计方法具有良好的估计性能。

The performance of channel estimator determines the performance of the MIMO systems because of the interference between various antennas and the inter-symbol interference （ISI）. The channel estimators for the MIMO system based on the second order statistics of the received signal are efficient. A channel estimator for the MIMO system based on the conjugate cyclostationarity of the received signal is proposed in this paper. The estimator cancels ISI and co-channel interference （CCI） by utilizing the relation between the cyclic auto-correlations of the received signals. It can anchor any element in the channel matrix, and then estimate the element by applying the training sequence. The estimator needn＇t know the channel order. Because the signal in the existing systems almost haven＇t the conjugate cyclostationarity, a method of constructing and utilizing conjugate cyclostationary signal is proposed in this paper at the same time. The simulation results show the estimator has good performance even when the channel order is overestimated.