Averaged threshold receiver for direct detection of optical communications through the lognormal atmospheric channel.

An averaged threshold receiver is developed for an optical communication system consisting of a symmetric binary, pulse-code modulated transmitter, a lognormal channel, and an array of independent photocounting detectors. When compared to previously described receivers, it is shown to be a much simpler structure to implement and to provide generally lower bit error rates. Probability of error curves demonstrating this improved performance are presented for various combinations of turbulence strength, background radiation level, SNR, number of diversity channels, and, in the newly developed processor, number of bits used for threshold averaging.