Analytical calculation of throughput of ALOHA based protocols in optical wireless data networks

An analytical framework for the calculation of the throughput performance of random-access protocols based on ALOHA is presented under blockage conditions in optical wireless data networks. A simple approximate Markovian channel model, which describes the channel variability, is proposed. Based on that, an analytical technique is developed for the calculation of the throughput of S-ALOHA paired with a general backoff-retransmission policy. It is shown that this combination can provide stabilised throughput performance under adverse blockage conditions. Calculation of the throughput for reservation ALOHA under the same channel conditions is described. The analytical techniques described are based on equilibrium-point analysis and their predictions are in very good agreement with Monte-Carlo-simulation results.