New decoding scheme for product accumulate code over an optical PPM channel

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.

Keywords

Original Scheme / Extrinsic Information / Iterative Decode / Decode Scheme / Outer Code

References

[1] LiJ., NarayananK. R., GeorghiadesC. N.. IEEE Trans. Inf. Theory, 2004, 50: 31

[2] ChenY., AulinT. M.. Electronics Letters, 2008, 44: 1211

[3] ZhangC., WangL., ChenG.. Circuits System Signal Processing, 2008, 27: 915

[4] Min Xiao, Lin Wang and Weikai Xu, 8th International Conference on Signal Processing, 2064 (2006).

[5] B. Moision and J. Hamkins, IPN Progress Report, 42 (2005).

[6] ten BrinkS.. IEEE Transactions on Communications, 2001, 49: 1727

[7] ten BrinkS., KramerG., AshikhminA.. IEEE Transactions on Communications, 2004, 52: 670