Dynamic contention windows adjustment based on the average number of consecutive idle slots

It is important to achieve high throughput and good fairness through MAC schemes in wireless LANs. Although lots of research efforts have been spent on improving the performance of IEEE 802.11, most of them focus on a single aspect while disregarding others. In this paper, we propose a novel MAC scheme called DCWA-ANCIS (Dynamic Contention Windows Adjustment based on Average Number of Consecutive Idle Slots). Firstly, we obtain the relationship between the normalized throughput χ and the average idle interval L_i. Secondly, through both theoretical analysis and simulations, we obtain an optimal range [L_imin, L_imax] of L_i corresponding to different frame lengths to make the throughput achieve or approach the maximum. Thirdly, according to the observed average idle interval L_i, each node dynamically adjusts its contention window (CW) to approach the optimal range of L_i. Through simulation comparison with previous MAC schemes, DCWA-ANCIS achieves much higher throughput and better fairness.