Performance Analysis of IEEE 802.11 DCF in Multi-hop Ad Hoc Networks

Analytic model is proposed to evaluate the packet delay, the delay jitter and the packet loss probability of IEEE 802.11 Distributed Coordination Function (DCF) in multi-hop Ad Hoc Networks. This model can also be easily extended to analyze the Enhanced Distributed Channel Access (EDCA). By modeling each node as a discrete time G/G/1 queue, the closed form expressions of the delay, the delay jitter and the packet loss probability in 802.11 DCF heterogeneous circumstances are derived. Simulation results agreed quite well with the analytical results. Based on this model, the impact of the maximum retransmission number and the minimum contention window on the performance of DCF is discussed. Analytical results suggest that the increase of the maximum retransmission number of one node decreases its packet loss probability dramatically, but has little influence on its delay and delay jitter and the performance of other nodes. Besides, the delay, the delay jitter and the packet loss probability of the tagged node increase and the packet loss probabilities of other nodes decrease slightly with the increase of the minimum contention window of the tagged node, but there is rare influence on the delay and the delay jitter of other nodes.