EDCA Based Congestion Control for WLAN Mesh Networks

Abstract

This paper proposes a simple yet effective congestion control mechanism for wireless mesh networks. Most mesh implementations today utilize the Institute of Electrical and Electronics Engineers (IEEE) 802.11 medium access control (MAC) protocol, which has been designed for single-hop networks. The performance of such a medium access mechanism in a multi-hop setting significantly degrades due to the specific characteristics of mesh networks that result in congestion and buffer overflow in intermediate mesh points (MPs). This paper proposes a hop-by-hop backpressure based congestion control mechanism where the downstream MPs feedback their forward rate to upstream MPs, which dynamically adjust their IEEE 802.11e enhanced distributed channel access (EDCA) parameters to ensure that their transmission rate matches the forward rate of their next hop neighbor. Simulation results show that the proposed scheme is capable of achieving significant throughput gains in a mesh network