Based on the basic expansion model (BEM), a novel joint iterative channel estimation and symbol detection algorithm for orthogonal frequency division multiplexing (OFDM) systems over time-varying channels is proposed for elimination of inter-carrier interference (ICI) caused by rapidly time-varying channels. The algorithm combines the BEM based minimum mean square error (MMSE) channel estimation with a symbol detection method like the successive interference cancellation, and uses interpolation and filtering to further eliminate noise, and then obtains the more accurate symbol detection result through joint iterative calculation. Meanwhile, the algorithm obtains the tradeoff between complexity and performance by using the banded matrix approximation. The theoretical analysis and the simulation results show that the novel joint iterative channel estimation and symbol detection algorithm can effectively improve the system performance over fast time-varying channels.%针对正交频分复用(OFDM)系统中由于信道快时变导致的子载波间干扰(ICI),基于基扩展模型,提出了一种时变信道下OFDM系统联合迭代信道估计与符号检测算法.该算法将基于基扩展模型的最小均方误差信道估计算法与一种类似于串行干扰抵消的符号检测方式相结合,并利用插值和滤波过程进一步消除噪声影响,进而通过联合迭代获得较为精确的符号检测结果.同时,利用带状矩阵近似降低算法的计算复杂度,在复杂度与算法性能之间取得比较好的折中.理论分析和仿真结果表明,在快时变信道条件下,这种新的联合迭代信道估计与符号检测算法可有效地提高系统性能.
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