Routing in multi-radio, multi-hop wireless mesh networks

We present a new protocol for routing in multi-radio, multi-hop wireless networks. Our protocol, Multi-Radio Link-Quality Source Routing, is designed for wireless networks with station-ary nodes, where each node is equipped with multiple indepen-dent radios. The goal of the protocol is to choose a high-throughput path between a source and a destination. Our protocol assigns weights to individual links based on the Expected Transmission Time (ETT) of a packet over the link. The ETT is a function of the loss rate and bandwidth of the link. The individual link weights are combined into a path metric called Weighted Cu-mulative ETT (WCETT) that explicitly accounts for the inter-ference among links that use the same channel. The calculation of WCETT can be tuned to either maximize throughput of the given flow or to minimize its impact on other flows. We studied the performance of our protocol by implementing it in a wireless testbed consisting of 23 nodes, each equipped with two 802.11 wireless cards. We used combinations of 802.11a, 802.11b and 802.11g radios in each node to explore the performance of our protocol. We find that our protocol significantly improves throughput by judicious use of a second radio. We also show that our proto-col significantly outperforms previously-proposed routing pro-tocols in a multi-radio environment.