This project addresses the scalability of wireless networks when steerable phase array antennas are used by a subset of the network and builds on earlier work resulting in a modified MAC layer for such steerable antennas. This earlier found that limited use of that steerability was needed; rather than change antenna configuration on a packet-by-packet basis, antenna configurations are designed to target a slowly changing set of nodes. That work begged the question of how those slowly changing sets of nodes should be formed. This project uses spatial diversity to improve the efficiency of the physical layer and proposes a network layer that enables efficient spatial reuse at the physical layer. This includes dynamically defining the topology, or connectedness, of the network as well as the routing, or use of available connections. This problem is challenging because phase array antennas not only change the direction of RF signal, they also vary the strength of that signal. This project includes development and use of a research network combining fixed and mobile nodes using a combination of steerable and fixes antennas. This platform will use SoftMAC, a low cost software defined radio, to deploy prototype systems for in-field experimentation. Example applications for this project include city- and emergency service networks, and the researchers will be working with local Police and Fire departments to understand, model and analyze usage scenarios for these highly dynamic networks. The work in this project should make these rapidly deployed wireless networks more flexible and resistant to failure.
