改进的迭代STBC-OFDM系统信道估计与解码算法  

Improved iterative channel estimation and a decoding algorithm for the STBC-OFDM system

作　　者：郑勇[1] 冯大政[1] 

机构地区：[1]西安电子科技大学雷达信号处理重点实验室,陕西西安710071

出　　处：《西安电子科技大学学报》2008年第4期691-695,共5页Journal of Xidian University

基　　金：自然科学基金资助项目(60072126)

摘　　要：提出一种针对空时块码正交频分复用系统在信道信息不确知情况下的低复杂度半盲联合信道估计与解码算法.与以往迭代最大似然接收机中通过搜索可能字符最大化代价函数的解码方法不同,新算法在每步迭代中首先解析地估计出信号值,然后利用有限字符性质将估计值量化为离散信号.此方法只包含简单的线性运算,同时充分利用了OFDM的信号特征和STBC的正交结构特征.对于采用两接收天线——Almouti STBC和8-PSK信号的系统,新算法复杂度仅为搜索算法的1/16,随系统复杂度增加,计算量的优势更为明显.仿真表明该算法与搜索算法相比性能只有少量损失.A low-complexity joint channel estimation and a decoding algorithm for the space-time block coded orthogonal frequency division multiplexing （STBC-OFDM） system in unknown channels is presented. Different from the decoding via exhaustive searching in the previous iterative maximum-likelihood （ML） receiver, in the new algorithm, the signals are estimated analytically, and then are quantized with the aid of the finite alphabet information. The proposed iterative algorithm only involves linear processing and exploits the special orthogonal structure of the STBC-OFDM signal. For a system with two receive antennas, if the Alamouti STBC and 8- PSK signal are adopted, the proposed method has 1/16 the complexity compared with the searching method. As the system complexity increases, the new method has more advantages over the searching method. Simulation results show that our method only has a little performance loss. On the other hand, by simulation, two applications of the new method on time-varying channel tracking and improving the performance of the system with an inserted pilot are given.

关 键 词：空时块码 正交频分复用 迭代最大似然接收机 

分 类 号：TN919.3[电子电信—通信与信息系统]