Service Differentiation in IEEE 802.11s Mesh Networks: A Dual Queue Strategy

Wireless Mesh Networks (WMNs) extend the concept of ad hoc multi-hop wireless communication to WLANs in an attempt to complement the wired infrastructure. Unlike in traditional WLANs where all the Access Points (APs) had to be connected to the wired infrastructure, in WMNs, only a subset of APs are connected to the wired infrastructure which cooperatively relay other´s traffic towards the Internet. Although WMNs are a good proposition for ubiquitous broadband connectivity, they suffer from serious spatial unfairness problem. Often, the proximity of nodes in a network to the main internet attachment plays a significant role in the performance obtained, which is highly undesirable in the envisioned scenario of WMNs. The prime motivation of this paper is to provide fair treatment to all users and provision guaranteed service to users that are attached to a far away AP. We propose a dual queue strategy that provides service guarantees to all users in the network irrespective of their spatial location. The algorithm is designed to elegantly segregate and exclusively reserve queues for either of the traffic. We implement this module above the standard IEEE 802.11 MAC layer thus obviating any modifications to the legacy MAC. Extensive simulations reveal that our proposed scheme substantially improves the performance of multihop flows.