为了比较Turbo码与不同发射分集技术的结合在对抗多径衰落时的作用 ,本文比较了Turbo -TCM方案分别与Alamouti提出的编码分集技术 (ACD)和传统的正交发射分集技术 (OTD)的级联系统在瑞利衰落信道下的性能。针对级联系统的译码 ,本文给出了一种具有低译码时延的次优译码算法 ,该算法的特点是各模块独立译码 ,先算比特对数似然比再进行二进制Turbo码译码。同时进行了仿真 In order to compare the effect of Turbo codes with different transmit diversity techniques in combating multipath fading, this paper compares Turbo-TCM scheme with Aramouti proposed code diversity (ACD) and traditional orthogonal transmit diversity (OTD) Cascaded system performance under Rayleigh fading channels. Aiming at the decoding of cascaded systems, this paper presents a suboptimal decoding algorithm with low decoding delay. The algorithm is characterized by independent decoding of each module, first bit-to-bit-likelihood ratio and then binary Turbo Code decoding. At the same time a simulation