MIMO系统中复数球形译码算法改进

多输入多输出（MIMO）系统在信道容量和频谱利用效率方面有显著的优势，但是在MIMO系统中南于接收信号空间大，用传统的最大似然译码准则（ML）来译码几乎是不可能的．而球形译码算法（spheredeco—ding）通过减小搜索半径大大降低了计算量，且可以达到ML的性能．本文在实数球形算法的基础上，着重对复数球形算法进行了分析，对二者做了比较．针对复数球形算法的特点，提出了一种简化方法．分析和仿真表明，相比实数球形算法，复数球形算法不仅可以减小搜索的维数，还有着更广的适用范同．该方法可以进一步减少复数球形算法的计算量，提高其实用性．

The Improvement of Complex Sphere Decoding Algorithm in the MIMO System

Multiple-Input-Multiple-Output （MIMO） system has the obvious advantage in channel capacity and band efficiency. However, the traditional ML decoding algorithm cannot be applied because of large signal space. The paper introduces Sphere decoding algorithm （SD） to reach the ML performance in the cost of less computation. The paper focuses on complex sphere decoding algorithm （complex SD） and compares it with the real sphere decoding algorithm. A simplified method in complex SD is presented in this paper. It can be shown that the complex SD algorithm greatly reduces the search dimension and has wider application. The new simplified method would reduce the computation and make complex SD more feasible.