.New decoding scheme for product accumulate code over an optical PPM channel[J].Optoelectronics Letters,2011,7(2):147-150 New decoding scheme for product accumulate code over an optical PPM channel 郭建中 College of Electronics & Information Engineering, Wuhan Textile University； School of Electronics Information, Wuhan University； Abstract:       A new decoding scheme for product accumulate (PA) code over a space optical Poisson/pulse-position modulation (PPM) channel is investigated. In this scheme, the PPM and the accumulator of the PA code are taken as a single inner code, decoded with an iterative demodulating-decoding technique based on Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm, rather than belief propagation (BP) algorithm in the original scheme. Simulation results show that this scheme provides much better bit error rate (BER) performance. At a BER of 10−5, the new scheme has a gain of 1.8 dB more than the original one. In addition, extrinsic information transfer (EXIT) charts are employed to analyze and compare the performance. The results indicate that the new scheme has not only better BER performance, but also lower error floor. Hits: 4302 Download times: 231 View Full Text    Download reader