Congestion Control based on AMC Scheme for WLAN Mesh Networks

Recently, Wireless Local Area Network (WLAN) mesh networks are attracting significant attention. Because the Institute of Electrical and Electronics Engineers (IEEE) 802.11 Medium Access Control (MAC) protocol has been designed for single- hop networks, the performance of WLAN mesh networks degrades due to congestion, and buffer overflow in intermediate Mesh Nodes (MNs). In this article, we propose new congestion control scheme which applies Adaptive Modulation and Coding (AMC) scheme and effective buffer usage to enhance the performance. AMC scheme uses multiple fragmentation thresholds, modulation levels and coding rates for various data sizes according to Channel State Information (CSI). Because CSI can be used more effectively to squeeze more bits into the medium, the throughput is enhanced. Simulation results show that the proposed scheme achieves much higher throughput than other congestion control schemes.