Designing Directional Antennas to Maximize Spatio-temporal Sampling Rates in Multi-hop Clustered Sensor Networks

In a clustered sensor network, a possibly large number of geographically distributed sensor nodes each make local measurements and transmit them toward the clusterhead. The clusterhead may schedule simultaneous transmissions from nodes within the cluster by identifying non-interfering areas in the cluster. Directional antennas that are oriented toward the clusterhead may increase this spatial reuse of the communication channel and thus increase the number of simultaneous, non-interfering transmissions. On the other hand, the directional antennas' narrower coverage areas may reduce connectivity, thus reducing the number of sensors from which data can be collected. In this paper, we investigate this tradeoff between spatial reuse and connectivity in the context of the spatio-temporal sampling rate that can be achieved by the cluster. We also propose a simple analytical approach to determine an antenna beamwidth that improves the spatiotemporal sampling rate by maximizing the transport capacity of the network.