中文摘要：

针对分组Turbo码自适应Chase译码算法中SNR是预先设定值的情况，提出一种新的自适应估计信噪比（SNR）的译码算法。该方案利用了接收码字的统计信息与SNR之间存在的对应关系来调整门限函数，达到控制译码复杂度的目的。仿真结果表明，所提出的译码算法能自适应反映信道情况，降低译码运算复杂度，提高译码处理速度，获得了较好的性能。

英文摘要：

Considering the fact that the SNR values in the adaptive Chase algorithm are prefixed in the literatures, a modified decoding algorithm for block Turbo codes was proposed, in which the level of the channel SNR was adaptively estimated. The proposed algorithm could tune the decoding complexity with aid of the relationship between the statistics of the received vectors and the channel SNR to change the threshold function. Simulation results show that the proposed algorithm decreases the decoding complexi- ty, speeds up decoding while achieving better BER performance. Furthermore, the proposed decoding algorithm can adapt to different SNR values without prefixing them.