Photon-Counting-Based Ultraviolet Communication System with Self Bit Synchronization Module

For ultraviolet (UV) communication systems with discrete Poisson channel and photon-counting-based receivers, commonly used synchronization scheme is to perform correlation at the start of each frame, but this scheme is difficult to correct the error caused by clock frequency offset within the frame. In this paper, a UV communication system with our self bit synchronization scheme is proposed. It adopts on-off keying (OOK) modulation, and uses the real-time result of photon counting module to synchronize the counting window without any extra input. The proposed scheme regards the input signal envelope as rectangular waves, matches and merges obvious edges detected, and computes moving distance. Our system achieves a bit error rate (BER) of $1.5\times 10^{-4}$ at 25.6 kbps bit rate when the average photon amount in a single bit 1 duration is at about 40.