Photocounting array receivers for optical communication through the lognormal atmospheric channel. 2: optimum and...

Performance characteristics are obtained for various optimum and suboptimum photocounting array receiver structures obtained in the preceding paper (Part 1). Probability of error curves are presented for the case of lognormal fading and for a variety of receiver configurations including the BPCM single-detector and array-detector processors and the BPOLM and BPIM single-detector processor. In addition to these approximate optimum processors, the suboptimum aperture integration and MAP receivers are evaluated in order to examine degradation of performance with increasing suboptimality. An optimum amount of diversity is shown to exist for the aperture integration receiver, with a fixed signal energy constraint. In a related paper (Part 3), we examine a bound to the error probability for M-ary signaling.