Distributed MAC adaptation for WLAN QoS differentiation

In current WLAN system that is designed for best-effort communications, there is not any quality of service (QoS) differentiation support. In this paper, we propose a fully distributed medium access control (MAC) adaptation method for service differentiation. It is implemented by dynamically updating the MAC layer parameters (such as contention window) to adapt to the network conditions in a class-based fashion. In this sense, the QoS classes are differentiated and the system performance is significantly improved in terms of delay, packet loss and throughput while ensuring fairness and stability. The key idea of our scheme is the introduction of a mapping function and a target contention window. It is demonstrated that our proposed adaptive MAC can outperform both the basic 802.11 MAC and the fixed differentiation scheme with very low complexity.