A 18-Mbp/s, 8-State, High-Speed Turbo Decoder

  • Jung Ji-Won (Department of Radio Science & Engineering, Korea Maritime University) ;
  • Kim Min-Hyuk (Department of Radio Science & Engineering, Korea Maritime University) ;
  • Jeong Jin-Hee (Department of Radio Science & Engineering, Korea Maritime University)
  • Published : 2006.09.01

Abstract

In this paper, we propose and present implementation results of a high-speed turbo decoding algorithm. The latency caused by (de) interleaving and iterative decoding in a conventional maximum a posteriori(MAP) turbo decoder can be dramatically reduced with the proposed design. The source of the latency reduction is come from the combination of the radix-4, dual-path processing, parallel decoding, and rearly-stop algorithms. This reduced latency enables the use of the turbo decoder as a forward error correction scheme in real-time wireless communication services. The proposed scheme results in a slight degradation in bit-error rate(BER) performance for large block sizes because the effective interleaver size in a radix-4 implementation is reduced to half, relative to the conventional method. Fixed on the parameters of N=212, iteration=3, 8-states, 3 iterations, and QPSK modulation scheme, we designed the adaptive high-speed turbo decoder using the Xilinx chip (VIRTEX2P (XC2VP30-5FG676)) with the speed of 17.78 Mb/s. From the results, we confirmed that the decoding speed of the proposed decoder is faster than conventional algorithms by 8 times.

Keywords

Turbo Code;Radix-4;Dual-Path Processing;Parallel Decoding;Early-Stop;FPGA

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