OFDM系统中基于EM迭代的时变信道估计与数据检测  

Time-varying Channel Estimation and Data Detection for OFDM Systems Via the EM Iteration

作　　者：陆许明[1] 徐永键[2] 陈里悦 谭洪舟[1] 

机构地区：[1]中山大学信息科学与技术学院,广东广州510006 [2]中山大学国光电子与通信研究院,广东广州市花都区510800

出　　处：《信号处理》2014年第7期757-765,共9页Journal of Signal Processing

基　　金：国家自然科学基金-广东联合基金重点项目(U0935002);广东省产学研结合科技创新平台(2012B090600009);物联网芯片与系统应用技术国家地方联合工程实验室(广东)(350001144001)

摘　　要：针对OFDM系统中难以实时获取时变信道统计信息的问题,提出了一种基于期望最大化(EM,expectation maximization)迭代的多符号联合信道估计和数据检测算法。为了获取合适的迭代初始值,利用梳状导频的信息,设计了基于最小二乘算法的低复杂度的初始化方案。通过分析算法中的信道统计量与信噪比的关系,提出了忽略信道自相关矩阵的简化算法,避免了获取信道统计信息的操作。仿真结果表明,提出的算法对信道的功率延迟分布和多普勒功率谱等统计信息不敏感,在未知信道多普勒功率谱的条件下,仍然具有较低的估计误差和误码率。Due to the difficuhy in obtaining real-time statistics of time-varying channels, a muhi-symbol channel estimation and data detection algorithm based on the expectation-maximization （EM） iteration was proposed for OFDM systems. In order to obtain a proper initial estimate for the iteration, a LS-based low-complexity scheme was implemented by making use of comb-type pilots. With the relationship between the channel statistics and signal to noise ratio in the proposed algorithm, a simplified algorithm with the channel autocorrelation matrix ignored was also introduced, and hence the operation of estimating channel statistics was avoided. Simulation results validate its robust properties to the absence of exact channel statistics such as power delay profile and Doppler power spectrum, and show that the normalized mean squared error and the bit error rate can be significantly reduced by this algorithm without exact Doppler power spectrum.

关 键 词：时变信道 期望最大化算法 信道估计 数据检测 

分 类 号：TN911.5[电子电信—通信与信息系统]