24 October 2012 Capacity of adaptive free-space optical channel using bi-directional links
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ABSTRACT Free space optical (FSO) communication experiences severe fading due to optical scintillation in long-range links. Adaptive schemes based on channel variation can utilize the channel capacity efficiently. In this paper, we propose a truncated variable rate adaptive scheme for FSO channel. We determined the improvement in channel capacity for perfect channel side information (CSI) at the transmitter and receiver using M-ary pulse position modulation (M-PAM) format. We also determined the improvement in capacity for an erroneous feedback channel using one link of a correlated bi-directional FSO link as a feedback link to the transmitter. Both synthetic and experimental channel samples are used to determine the gain. For perfect CSI we have 1-2 dB improvement in channel capacity compared to non-adaptive schemes using 2-PAM and 4-PAM modulation. For an erroneous feedback channel the improvement depends on the channel correlation coefficient. With medium to high correlation it gives good capacity improvement.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Afsana Khatoon, Afsana Khatoon, William G. Cowley, William G. Cowley, Nick Letzepis, Nick Letzepis, "Capacity of adaptive free-space optical channel using bi-directional links", Proc. SPIE 8517, Laser Communication and Propagation through the Atmosphere and Oceans, 85170X (24 October 2012); doi: 10.1117/12.929212; https://doi.org/10.1117/12.929212


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