CBFF信道下基于信道辨识自适应Turbo码译码算法研究

New Algorithm Based on Channel Identification for Adaptive Turbo Decoding over CBFF Channel

分析了分组相关快衰落信道(CBFF)的特性,推导出该信道下T urbo码译码算法;研究了信噪比对系统性能影响的规律,将信噪比分布分为高信噪比区、中信噪比区和低信噪比区;利用聚类分析,对当前信道进行辨识,对于不同的信道状态,自适应选择迭代译码次数,此方案可以兼顾系统性能和译码速度,得到较低的平均误比特率和较高的平均译码速度。仿真结果说明,在分组相关快衰落信道下,与固定迭代次数译码和相关文献中的自适应算法相比较,采用文中提出的基于信道辨识的自适应T urbo码译码算法,兼顾性能与速度,误比特性能和译码速度上均有所提高。

With the knowledge of correlated block fast fading channel, a new Turbo decoding algorithm is proposed. After studying the rule between performance and SNRs, we classify the channel into high SNR channel, medium SNR channel and low SNR channel. And then, identifying the current channel using clustering analyses, we propose a new scheme based on adaptive selection of iterations for different channel state. Considering both performance and speed of the decoding process, the proposed scheme is proved to decrease the mean BER and accelerate the decoding. The simulation results show that the proposed decoding algorithm can speed the decoding process without the loss of performance, compared with the fixed iteration scheme and adaptive scheme proposed in other references.