Design and analysis of turbo decoder for China 3rd generation mobile communication system

This paper presents a short-latency Turbo-codes decoder for the 3rd generation mobile communication system. In the decoder, we employed a modified sliding window log-BCJR (SW-log-BCJR) algorithm in which two sliding windows are working in parallel. With this algorithm the decoding latency of Turbo-codes decoder is half reduced and the complexity and memory increment is reasonable. Simulation shows that if we properly choose the size of the sliding window length, the performance degradation of the proposed algorithm is within 0.2 dB at BER=10(-5) relative to BCJR algorithm. Turbo decoder using the proposed algorithms is implemented on single-chip Xilinx FPGA and up to 2Mbps throughput is reached.