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Hybrid ARQ for FSO Communications Through Turbulent Atmosphere

Hybrid automatic-repeat request (HARQ) technique is investigated for binary pulse-position modulation (BPPM), free-space optical (FSO) communications through turbulent optical channels. It is assume that the received optical signal is detected using a direct-detection (DD) mechanism and that shot-noise, background noise, and thermal noise are present at the receiver. Performance of the HARQ-FSO system is assessed in terms of packet error rate, and is compared with that of a conventional ARQ-FSO system to draw conclusions about the effectiveness of HARQ mechanism in circumventing the impact of turbulence.