Abstract: In this paper,we discuss the design of turbo code used by UMTS.Combining the sliding window method with forward state metric as an accuracy initialization value with a modified Log-MAP algorithm(Linear-Log-MAP),which is called Sliding Window-Linear-Log-MAP algorithm,we design the VLSI architecture for turbo decoder.Moreover,we present a method for normalizing the forward recursion that yields a 12.5% savings in memory usage.The FPGA result shows that our presented structure(SW-Linear-Log-MAP) results in only 0.2 dB away from the optimal structure(Log-MAP) at BER= .It has also a 30% hardware cost savings ,a small decoder delay and a high throughput.

摘要： 本文讨论UMTS中turbo码的设计，提出采用前向状态度量作为初始化精确值的滑动窗方法和改进的Log-MAP（线性Log-MAP）相结合的算法(称为滑动窗-线性-Log-MAP算法)，设计出turbo码的VLSI结构，且在归一化处理时，介绍一种可节约12.5%存储量的方法。FPGA设计结果显示在BER= 时，与最优算法Log-MAP相比，性能损失0.2dB，硬件资源节约30%，译码时延小，吞吐量大。