中文摘要：

该文在软输出固定复杂度球形译码（SFSD）算法的基础上,提出一种低复杂度高性能的MIMO迭代检测方法。该算法利用迭代过程中译码器的反馈信息更新SFSD检测算法的软输出,获得明显的迭代增益,并利用多级比特映射星座图的特点大大降低分支度量的运算次数。针对SFSD算法预处理复杂度较高的问题,该文将检测顺序调整和QR分解两个预处理步骤相结合,从而减少了矩阵求逆运算。在长期演进方案（LTE）下行链路环境中的仿真结果表明,该文提出的算法性能十分接近最优的最大后验概率（MAP）检测,并且实现复杂度相对于MAP有显著的下降。

英文摘要：

This paper proposes an efficient iterative detection algorithm for MIMO systems, based on the Soft Fixed-complexity Sphere Decoder （SFSD）. The algorithm updates the soft output of SFSD using the feedback of the decoder, thus obtaining substantial iterative gain. The number of the branch metric calculation is reduced by exploiting the feature of the multi-level bit mapping constellation. The steps of the detection ordering determination and the QR decomposition are combined, in order to reduce the number of matrix inversion operations in the preprocessing stage. Simulation results in the Long Term Evolution （LTE） downlink system show that, the performance of the proposed algorithm approaches very close to that of the Maximum A Posteriori （MAP） detection with much lower complexity.