Design and analysis of sliding window ARQ protocols with rate adaptation for burst transmission over FSO turbulence channels

This paper studies a cross-layer design of error-control protocols with rate adaptation for a free-space optical (FSO) burst transmission over atmospheric turbulence channels. Specifically, sliding window automatic repeat request (ARQ) protocols are designed so that the window size is determined by the burst duration. This facilitates an effective operation for sliding window protocols with the adaptive rate (AR) transmission over atmospheric turbulence channels. To analyze performance of the design, the time-varying behavior of the atmospheric turbulence channels, modeled by the popular gamma-gamma (ΓΓ) distribution, is captured to develop the burst error model. An embedded Markov model, which is formulated in the discrete time defined by the burst duration, is analyzed based on the developed burst error model. Using the queueing analysis, the frame loss rate, average delay, and system throughput are analytically derived. Numerical results quantitatively demonstrate the impact of atmospheric turbulence on the system performance and support the optimal selection of system parameters over turbulence conditions. Monte Carlo simulations are also performed to validate the analytical results, and an excellent agreement between the analytical and simulation results is confirmed.