一种低复杂度球译码算法在STBC-OFDM中的应用

STBC-OFDM系统能够提供分集增益和编码增益,但采用ML(最大似然)译码时计算量很大,满足不了高速实时通信系统的要求。本文提出了一种在球半径范围内搜索向量的方法,即球译码方法,并在复域内提出一种基于重新排序的更好的搜索算法。该算法通过优化球半径迭代,加快了信号矢量搜索速度。仿真结果显示:与其他方法比较,该算法在计算量方面具有更大优势,平均浮点运算降低了大约75%,大大提高了运算效率。

Application of A Low Complexity Sphere Decoding Algorithm in STBC-OFDM

STBC-OFDM systems can provide diversity and coding gains.However,ML(Maximum Likelihood) has expensive computational complexity,which can not satisfy the need of high-velocity and real-time communication system.This paper presents a sphere decoding algorithm that searches new vector in a sphere radius.The central part of the algorithm is a modulation-independent sphere decoding framework formulated in the complex domain.This paper presents a new better searching method based on(reordered) vectors in complex field.This approach optimizes sphere radius iteration,increases the searching speed of signal vector.In order to compare with other algorithms,this paper develops two decoding(approaches): a modulation independent approach applicable to any memoryless modulation method,a QAM-specific fast decoding algorithm performing nearest-neighbor signal point search.The computational complexity of the algorithms is investigated via both analysis and simulation.The result of simulation shows this approach has more superiority on computational complexity and increases the efficiency of decoding,which demonstrate that the proposed algorithm can significantly reduce the decoding complexity.We observe up to 75% reduction in the required FLOP count percode block compared to previously existing methods without noticeable performance degradation.