A novel non-equidifferent optical APPM mapping scheme for strong turbulent atmospheric channel

An optical Amplitude and Pulse Position Modulation (APPM) mapping scheme for strong turbulent atmospheric channel is proposed to optimize Bit Error Rate (BER) performance. In this scheme, a non-equidifferent amplitude series is designed based on quantitative BER analysis of the specific A×M APPM demapping procedures containing time slot selection and amplitude decision in selected time slot, which are different from traditional ones. Simulation results of 4×4, 4×8 and 4×16 APPM show 4, 3.4 and 6.9 dB SNR gain against traditional APPM scheme respectively. Thus significant BER performance improvement is achieved which helps to enhance reliability of free-space optical communication systems.