A new adaptive MAC protocol with threshold for wireless LANs

It is important that the distributed contention based protocol-DCF provide an efficient mechanism to share limited spectrum resources, together with simplicity of operation, high fairness in serving all stations and high throughput performance. In this paper, we propose a new scheme called adaptive fair DCF which focus on the limitations of the IEEE 802.11 DCF and extent IEEE 802.11 DCF by increasing the contention window size during periods when the channel is busy, by using an adaptive fast backoff mechanism when the channel is idle, and by adaptive channel gain threshold when the channel gain is good or bad. The new scheme significantly improves the fairness and throughput performance. Moreover, it holds the high throughput when the station´s channel suffers periods of severe decay. The extensive simulation studies show that the ADCF algorithm could significantly improve the performance of the IEEE 802.11 MAC protocol.