Performance analysis of TCP over free-space optical links with ARQ-SR

This paper presents an analytical study on the performance of transmission control protocol (TCP) over free-space optical (FSO) links when the automatic-repeat request, selective repeat (ARQ-SR) scheme is used for the link layer. Using a three-dimensional (3-D) Markov model, we analytically derive the TCP throughput and energy-throughput efficiency, which is the the ratio between the TCP throughput and the average energy for transmitting an unit data of TCP. In the numerical analysis, we quantitatively discuss the impact of various FSO physical and link layer parameters on the trade-off between the energy consumption and the TCP throughput.