Simulation of Photon-Counting Wireless Communication System Based on QAM Modulation

In order to study the application of high order modulation in single photon counting communication, a 16 QAM modulation communication system based on MATLAB platform was established by modeling the characteristics of single photon detector. We represent the transmitted signal as a single photon and perform equal interval counting at the receiving end to recover the signal and demodulate it. The influence of different illumination intensity, different sampling rate, different dark counting rate and different equal time interval partition on system bit error rate is studied. The experimental results show that BER decreases with increasing light intensity. When 1250 photons are used for per symbol, the BER reaches 5 × 10 ^-4, which can meet the requirements of communication system. In addition, counting at different equal time intervals is actually a process of resampling the signal. Therefore, the higher the sampling rate of the transmitter is, if the receiver needs to recover the signal with the same sampling rate, it will be easier to reach the photon saturation state when counting at equal time intervals, and more likely to cause a large bit error rate. The dark counting rate has great influence at low light intensity, but decreases with the increase of light intensity.