基于改进的译码算法的空时Turbo网格码

The ST-Turbo TC Based On the Improved Decoding Algorithm

Turbo码因具有接近香农极限的性能,在通信领域一直是研究的热点。但其本身迭代译码的结构使得该码的译码算法的复杂度非常大,很大程度上限制了它的广泛应用。本文采用改进的Log-MAP算法对空时Turbo码(ST-Turbo码)在衰落信道下的译码性能进行分析。该算法是利用MacLaulin序列将Log-MAP的修正函数用Max函数取代,从而大大降低了计算的复杂度,提高了硬件系统的运行速度。计算机仿真表明在衰落信道下该算法可以达到与Log-MAP相近的性能。

As the performance of Turbo code is very closely to Shannon limit, it has been the focus of the research in the telecom- munication field. However, the iterative decoding structure makes its decoding very complicate, which confines its extensive applica- tion. This paper adopts the improved Log-MAP algorithm for Space-Time Turbo （ST-Turbo） decoding in fading channels. Using the MaeLaulin formulae, the proposed algorithm expand the logarithmic function of the Log-MAP. It makes the computation much easier and speeds the operation of the hardware system. Simulation results show that the proposed algorithm performs very closely to the Log-MAP algorithm for ST-Turbo decoding in fading channels.