一种低复杂度的差分酉空时调制多符号球形译码算法

A Low Complexity Multiple-Symbol Differential Sphere Decoding for Differential Unitary Space-Time Modulation

该文提出了一种瑞利衰落信道下差分酉空时调制系统中多符号差分球形译码的改进算法。该算法在执行球形译码的最大似然度量搜索时,仅对具有较小最大似然度量的部分测试符号进行搜索,从而大大减少了搜索的次数,同时提出了一种逐项进行的最大似然度量计算方法,可以尽早发现超过搜索范围的测试符号并终止计算,在避免无谓的运算负担的同时得到所需的具有较小最大似然度量的部分测试符号。仿真表明,在适中的信噪比范围内,该算法在牺牲少量系统性能的基础上降低了超过50%的运算量。

In this paper, an improved multiple-symbol differential sphere decoding for differential unitary space-time modulation is presented. According to this algorithm, the sphere decoding process only search the trial symbols with less Maximum Likelihood （ML） metrics rather than all the symbols in the constellation, and an ＂element-by-element＂ calculation method is also presented to compute the ML metric which facilitates an early detection of trial symbol with large ML metric. Simulations show that the presented algorithm can significantly reduce the computational complexity with nearly no performance degradation in moderate SNR range.