SWARM: The Power of Structure in Community Wireless Mesh Networks

Community wireless networks (CWNs) have been proposed to spread broadband network access to underprivileged, under-provisioned and remote areas. Research has focused on opti-mizing network performance through intelligent routing and scheduling, borrowing solutions from mesh networks. Sur-prisingly, however, there has been no work on how to make efficient use of multiple channels in CWNs in the presence of multiple gateways, and a single radio per device. In fact, today’s deployments in under-privileged areas are primarily single radio and do operate on a single channel [19]. Fre-quency selection in such CWNs is very complex because it does not only determine the nodes ’ channel of operation but also the gateway and the routing tree to the gateway- a rather computationally intensive task. In this paper, we propose, design, implement, and evaluate SWARM, a prac-tical system that allows a CWN to make effective use of the available wireless channels in order to offer globally optimal performance. SWARM improves performance versus current single channel protocols by up to 7.7 × in our experiments. Moreover, while we should be expecting performance gains due to channel diversity, we clearly demonstrate that up to 3.7 × improvement is attributed to the network organization into efficient traffic distribution structures