Flag dual amplitude pulse position modulation for atmospheric FSO communications

In this paper, we propose a novel flag dual amplitude pulse position modulation (FDAPPM) for free space optical (FSO) systems in atmospheric turbulence-induced fading channels. The proposed scheme provides low receiver complexity due to the build-in symbol synchronization and does not have the insertion/deletion errors because of the fixed symbol length. Symbol structure and transmission rate of the FDAPPM are introduced. The conditional pairwise error probability (PEP) of the FDAPPM FSO system in gamma-gamma turbulence-induced fading channels is derived, and a closed-form of the unconditional PEP in terms of Meijer G-function is presented. A high SNRs asymptotic bit error probability (BEP) of the proposed scheme is presented, and the diversity order and SNR modulation gain are also derived. Numerical results are further demonstrated to confirm the analysis of the error performance of the FDAPPM and compared with the conventional modulation schemes.