一种用于高频谱利用率非确定性MIMO系统的高效球形译码算法

摘要

Sphere decoding (SD) is an efficient detection algorithm for multiple-input multiple-output (MIMO) systems. However, the optimal solution and the lowest search tree can not be guaranteed simultaneously in previous works for underdetermined MIMO systems. In order to solve this problem, an efficient algorithm is proposed, which equivalently transforms maximum-likelihood cost metric by adding a constant for obtaining both the optimal solution and the lowest search tree associated with SD and hence results in significant reduction in search complexity. Simulation results show that the proposed algorithm is more efficient than Algorithm Modified Cui and Tellambura (MCT) in search complexity for high order quadrature amplitude modulation (m-QAM, M>4) and give the optimal parameter for the lowest complexity as well.%球形译码是多输入多输出( MIMO)系统中一种高效的检测算法.但对于非确定性MIMO系统,已有球形译码算法不能同时获得最优解和最低搜索树.针对该问题,提出了一种高效球形译码检测算法,通过增加常量对最大似然代价函数进行等价转化,使得球形译码算法获得最优解的同时具有最低搜索树,大大降低了球形译码算法中的搜索复杂度.仿真结果表明,对于高阶正交幅度调制(M-QAM,M＞4)方式,本文算法优于修正的CT( Modified Cui and Tellambura,MCT)算法,大大提高了球形译码中的搜索效率.此外,仿真结果给出了最小复杂度下的最优参数值.