基于改进广义Steiner估计的MC-CDMA系统空时多用户检测

Space-time multiuser detection for MC-CDMA system based on improving generalized Steiner estimator

研究了频率选择性瑞利衰落信道中的同步MC-CDMA系统上行链路空时信道估计及多用户检测算法。考虑对应于子载波的衰落系数是信道冲激响应的离散傅里叶变换,通过在两个数据块之间插入训练序列(midamble)进行所有用户的联合信道估计。首先采用广义Steiner估计器(GSE)来进行阵列天线信道冲激响应的初始估计,然后提出一种简单有效的适用于均匀线阵的互相关波达方向(CCDOA)估计算法,用以改进阵列天线信道冲激响应的估计,从空间的角度降低了信道响应中的噪声。在估计出所有用户空时信道参数的基础上,构造最大比合并(MRC)、解相关检测和最小均方误差检测(MMSE)来进行信号检测。仿真结果表明基于互相关DOA估计的改进信道估计算法与广义Steiner估计器相比在系统性能上有显著的改善。

The space-time channel estimation and multiuser detection algorithm for the uplink of multicarrier CDMA (MC-CDMA) system in frequency selective Rayleigh fading channel were investigated. Considering that the fading coefficients corresponding to subcarriers were discrete Fourier transform of channel impulse response, we performed joint channel estimation for all users by inserting a midamble into two data blocks. The initial estimation of array antenna channel impulse response was first made according to the generalized Steiner estimator (GSE). Then a simple efficient cross-correlation direction-of-arrival (CCDOA) estimation algorithm for uniform linear array was presented to improve the estimation of array antenna channel impulse response. We reduced the noise in channel response from the view of space. After estimating the space-time channel parameter of all users, maximum ratio combining (MRC), decorrelating detection and minimum mean square error (MMSE) detection were constructed to perform signal detection. Simulation results show that the improved channel estimation algorithm based on CCDOA leads to a significant system performance improvement compared with the GSE.