Bit-error-rate performance of high-order APPM and AOPPM for non-Kolmogorov gamma–gamma channel FSO communications

High-order pulse modulations in free space optics (FSO) communication are of practical value, and non-Kolmogorov gamma–gamma (GG) channel model is the most suitable for FSO channel. However, research on a system combined with the above is rarely reported. In our work, we propose high-order (4*32 and 4*64) amplitude and pulse position modulation (APPM) and overlapping amplitude and pulse position modulation (AOPPM) FSO communication system under a modified non-Kolmogorov GG turbulent channel model. Simulation results present that AOPPM is obviously better than APPM in bit-error-rate (BER) performance, and BER performance grows with the increase of modulation order (number of pulse positions). The proposed schemes may provide a reference for system design and practical application.