Intra-Mesh Congestion Control for IEEE 802.11s Wireless Mesh Networks

Wireless mesh networks (WMNs) are a convenient type of Internet access networks, because they are self-configuring and self-healing wireless multi-hop networks. This is in particular true for IEEE 802.11 based WMNs as they cover large areas, are easy and cheap to setup, and provide sufficient capacity. Despite these advantages, WMNs have not yet entered the mass market. One of the reasons for this is, that many existing WLAN mesh networks use their own specific combination of higher layer protocols and IEEE 802.11 MAC extensions what makes it hard to characterize their performance and to provide interoperability. The recently published IEEE 802.11s-2011 standard addresses this issue by introducing standardized MAC layer mechanisms for WLAN mesh networking. One of these mechanisms is the IEEE 802.11s intra-mesh congestion control (IMCC) framework which addresses one of the key challenges in contention-based WMNs, namely congestion on the wireless medium. In this paper we quantify the benefits of this framework by introducing and evaluating three IEEE 802.11s-compliant IMCC algorithms. An extensive simulation study reveals that in dependence on the different levels of complexity of the algorithms-node-specific (TCC), link-specific (LSCC), or path-specific (PSCC)-the network performance in terms of throughput and fairness can be significantly improved.