TCP Dynamics and Adaptive MAC Retry-Limit Aware Link-Layer Adaptation over IEEE 802.11 WLAN

In this paper, we have developed a cross-layer approach which combines real-time retry-limit (RTL) adaptation at medium access control (MAC) layer, with transport control protocol (TCP) dynamics aware link adaptation at link-layer in IEEE 802.11 wireless local area networks (WLANs). TCP throughput can be enhanced by raising the RTL, but latency and bandwidth overheads due to retransmission increase with RTL and additional control traffic must flow to request retransmissions. Thus, dynamic optimization of retry-limit setting within MAC layer is considered in conjunction with link adaptation based on the wireless channel conditions, traffic characteristic, and by invoking the knowledge of TCP protocols in order to achieve higher throughput at low frame loss rate.