Turbo码解码过程中的加权算法

本文通过调整迭代解码过程中系统位接收值的加权系数，提出了一种Turbo码加权迭代解码算法。该算法改变了迭代运算后Turbo码解码器输出软值中系统位接收值信息和它的外部估计信息的比重，使Turbo码无论在低信噪比或是在高信噪比时均具有优良的纠错性能。仿真结果显示，采用Turbo码加权迭代解码算法，不仅能提高Turbo码的收敛速度，而且能进一步降低Turbo码解码时的地板值，使Turbo码的比特误码率在高、低信噪比时都能够得到进一步改善。

A Weighted Algorithm for Decoding of Turbo Codes

By adjusting the weighted coefficient of received signals in terms of the changes of SNR(Signal-to-Noise Ratio), this paper proposes a novel iterative weighted soft decoding for Turbo codes, which alters the distribution of the received symbols and their complements in the soft outputs of Turbo decoder by means of iterative decoding. In this way, the outputs of Turbo decoder can obtain better performance than before by adjusting the weighted value according to the different values of SNR. Simulation results show that the proposed scheme can not only accelerate the decoding convergence but also reduce the floor value of Turbo codes. Furthermore, it can improve the error correcting performance of Turbo codes no matter in high or low SNR. Especially, the proposed decoding scheme is suitable for those channels where the SNR is constantly changing.