Performance analysis of priority schemes for IEEE 802.11 and IEEE 802.11e wireless LANs

The IEEE 802.11 distributed coordination function (DCF) enables fast installation with minimal management and maintenance costs, and is a very robust protocol for the best effort service in wireless medium. However, the current DCF is unsuitable for real-time applications. This paper studies backoff-based priority schemes for IEEE 802.11 and the emerging IEEE 802.11e standard by differentiating the minimum backoff window size, the backoff window-increasing factor, and the retransmission limit. An analytical model is proposed to derive saturation throughputs, saturation delays, and frame-dropping probabilities of different priority classes for all proposed priority schemes. Simulations are conducted to validate analytical results. The proposed priority schemes can be easily implemented, and the results from this paper are beneficial in designing good priority parameters.