多符号差分检测的低复杂度球形译码设计

Design of low complexity sphere decoding for multiple symbol differential detection

在多符号差分检测系统中,深度优先的球形译码是一种典型的次优的检测算法。然而从复杂度角度来说,它仍有较高的计算复杂度,且存在流水线和并行操作困难等缺点。针对这些问题,目前主要从两个方面对该算法进行改进:一是通过选择合适的约束半径来降低复杂度;二是与K-Bes(tM)算法结合来解决并行操作问题。主要研究前者,并在现有的理论基础上,提出了两种半径选择方法,即线性半径和非线性半径。仿真结果表明,两种半径约束下的球形译码在复杂度上低于最大似然检测却同时能保证它们的性能损失小于0.5dB。

The depth-first sphere decoding is a classical sub-superior detect algorithm in the Multiple Symbol Differential Detection （MSDD） system. However, from the view of complexity, it still has a high computational complexity, and there are difficulties in pipeline and parallel operations. To solve these problems, it focuses on two ways to improve the algorithm at the present： first, choosing appropriate radius to reduce complexity; second, combining with K-Best （M） algorithm to solve the parallel of operational problems. The paper mainly studies the former, and proposes two radius selecting methods based on existing theory, namely linear radius and nonlinear radius. Simulation results show that the sphere decoding with two radiuses has lower complexity than the Maximum Likelihood （ML） detection with the loss of their performance less than 0.5 dB.