9409439 Kiasaleh Although fiber-optics systems are known to be quite reliable in terms of probability of bit error, multiple-access systems such as fiber-optic code-division multiple-access (FO-CDMA) systems suffer from user-induced interference. Other optical channels, such as free-space optical channels, are impaired by other adverse link conditions, such as pointing error, turbulence, small received signal power, etc. Error control coding is an important means of achieving the needed improvement in the performance of photon channels. In particular, convolutional codes have been recognized as the suitable coding scheme for high bit rate photon channels. The focus of this research is on the introduction and performance evaluation of a recently proposed jointly optimal synchronizer/decoder receiver structures, known as Joint Viterbi Decoder (JVD)and Enhanced Viterbi Decoder (EVD), for convolutionally-encoded pulse-position modulation (PPM) and overlapping PPM (OPPM) systems. The objective here is to introduce compact, implementable decoders that can achieve near optimum performances. A very-large-scale-integration (VLSI) implementation of the proposed decoder will also be attempted. ***
