  In recent years, there has been a growing interest in exploring the
application of single-photon avalanche diode (SPAD) in optical wireless
communication (OWC). As a photon counting detector, SPAD can provide much
higher sensitivity compared to the other commonly used photodetectors. However,
SPAD-based receivers suffer from significant dead-time-induced non-linear
distortion and signal dependent noise. In this work, we propose a novel
SPAD-based OWC system in which the non-linear distortion caused by dead time
can be successfully eliminated by the pre-distortion of the signal at the
transmitter. In addition, another system with joint pre-distortion and noise
normalization functionality is proposed. Thanks to the additional noise
normalization process, for the transformed signal at the receiver, the
originally signal dependent noise becomes signal independent so that the
conventional signal detection techniques designed for AWGN channels can be
employed to decode the signal. Our numerical results demonstrate the
superiority of the proposed SPAD-based systems compared to the existing systems
in terms of BER performance and achievable data rate.
