End-to-End Performance Aware Association in Wireless Municipal Mesh Networks

Abstract

In wireless municipal mesh (muni mesh) networks, a client station needs to associate with a mesh access point (MAP) in order to access the network. The end-to-end performance of a station depends on the access link quality between the station and the associated MAP as well as the multi-hop path quality from the associated MAP to the Internet gateway. However conventional association mechanisms used for single-hop WLANs assume that the wireless access link is the bottleneck and do not take the backhaul conditions into account, which may result in poor performance in muni mesh networks. In this paper, we propose a new joint MAP association mechanism for muni mesh networks to achieve optimal end-to-end communication performance from the station to the gateway. A station associates to one of its nearby MAPs by jointly considering the transmission capability of the access link and the backhual path. In addition, we design a new metric, called CAETT, to measure the access link quality. Different from previously proposed link metrics, CAETT takes into account the impact of 802.11 MAC layer contention on bandwidth sharing among the stations with multi-rate capability. It yields more accurate link throughput estimation. Furthermore, in order to reduce the association time, we develop an analytical model and propose a hybrid measurement/estimation method to enable a station to quickly determine the CAETT. We evaluate the performance of our system through simulations and demonstrate that the proposed joint association mechanism with the CAETT metric can greatly improve the end-to-end performance for the stations.