Experiences with a Metropolitan Multiradio Wireless Mesh Network: Design, Performance, and Application

Wireless mesh networks comprise nodes with multiple radio interfaces, and can provide low-cost high-speed Internet access or connectivity for data transfer. In this article we report our experiences and investigations with an experimental metropolitan multiradio mesh network that covers an area of approximately 60 km² in the city of Heraklion, Crete. We present the design and deployment of the network, experiments to quantify the network's performance, and an application that runs on top of it and exploits it's low-cost wide-area connectivity. The metropolitan network consists of 16 nodes, among which six are core nodes, each with up to four 802.11a wireless interfaces and an additional wireless interface for management and monitoring. The distance between core mesh nodes varies from 1.6 to 5 km, and the mesh network contains two gateways that connect it to a wired network. Our performance experiments involve rate, power, and channel control for long-distance metropolitan links, and include investigations of the timescales for the operation for these mechanisms. Finally, we present a system for continuous online electromagnetic field monitoring and spectrum sensing, which utilizes the metropolitan mesh network for collecting wide-area measurements from low-cost EMF measurement devices.