A simple but accurate throughput model for IEEE 802.11 EDCA in saturation and non-saturation conditions

This paper presents a novel mathematical model of the IEEE 802.11 Enhanced Distributed Channel Access (EDCA) function. The main advantage of the model is that it combines accurate probability of counting down backoff slots with proper handling of frames. Furthermore, it allows for traffic differentiation with the use of traffic priority-dependent access parameters, i.e., AIFSN, and CW. Additionally, a new method of modelling AIFS differentiation between traffic classes is proposed. Finally, the model is kept reasonably simple and constructed in such a way that taking into account the four-way-handshake mechanism is uncomplicated. The proposed model is compared with simulations as well as numerical results obtained for two other models presented in the literature. The comparison gives satisfactory results regardless of the offered load, number of nodes, or network configuration.