We analyze the error performance of overlapping multipulse pulse position modulation (OMPPM) in optical direct-detection channel with existing noise. Moreover we analyze the error performance of trellis-coded OMPPM with the small overlap index N = 2 in optical direct-detection channel to achieve significant coding gains over uncoded PPM, uncoded MPPM and the trellis coded overlapping PPM (OPPM) with the same pulsewidth. First we analyze the symbol error probability of OMPPM in both the quantum-limited case and the quantum and background noise case by using the distance defined as the number of nonoverlapped pulsed chips between symbols. Second by using this distance, we partition the OMPPM signals and apply the four-state and the eight-state codes described by Ungerboeck, to OMPPM. It is shown that the trellis coding over OMPPM is effective in optical direct-detection channel: the eight-state trellis coded (4,2,2) OMPPM can achieve gains of 3.92 dB and 3.23 dB over uncoded binary PPM in the quantum-limited case and in the quantum and background noise case with noise photons per slot time is one, respectively.
|Number of pages||11|
|Journal||IEICE Transactions on Communications|
|Publication status||Published - 1994 Sep 1|
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering