In order to realize Turbo decoding of VDES data segment accurately and efficiently,two main methods of iterative decoding are analyzed and studied:Soft Output Viterbi Algorithm(SOVA)and Bahl Cocke Jelinek Raviv(BCJR).The decoding performance,computation and resource consumption when the hardware implementation of the two algorithms are also compared and analyzed.Two link signals ID20 and ID21 with different code rates in VDES are selected to the analyze the influence of iteration times on the decoding performance of two algorithms.The bit error rate curves and frame error rate curves of the two algorithms are given.The Matlab simulation results show that both algorithms can achieve frame error rates below 10-1 under the minimum signal-to-noise ratio required by the VDES standard.The decoding performance of the BCJR is better than that of the SOVA,but the amount of calculation is significantly higher than that of the SOVA algorithm.When considering using DSP to implement the Turbo decoding,SOVA takes less time than BCJR.But BCJR takes less time when it is implemented with FPGA.
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维普
