Optical Wireless Scattering Communication System with a Non-Ideal Photon-Counting Receiver

Consider the optical wireless scattering communication with a photomultiplier tube (PMT) receiver utilizing finite small intervals for measuring the PMT outputs. The analog output signal for each symbol consists of a vector of the signals within the intervals. We propose the signal model for the nonideal photon-counting receiver with a preset threshold for the hard decision on whether a photoelectron exists in each interval. Two threshold selection rules on the detection error probability and the related Kullback-Leibler (KL) distance are proposed. We further prove that for small shot and thermal noise variances, the KL distance is not sensitive to the detection threshold selection, which shows that the detection threshold can be selected among a wide range without significant loss from the optimal KL distance. The performances of the proposed signal detection and the optimal threshold selection approaches for the non-ideal photon-counting receiver are evaluated by the numerical results.