Supporting Deadline Monotonic Policy over 802.11 MAC Layer Service Time Distribution

In this paper, we propose a real time scheduling policy over 802.11 DCF protocol called deadline monotonic (DM). We evaluate the performance of this policy for a simple scenario where two stations with different delay constraints contend for the channel. For this scenario a Markov chain based analytical model is proposed. From the mathematical model, we derive the probability distribution of the packet service time at MAC layer. Analytical results are validated by simulation results using the ns-2 network simulator.