Effect of Directional Antennas on Spatiotemporal Sampling in Clustered Sensor Networks

In a sensor cluster, a 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 spatial reuse and thus increase the number of simultaneous transmissions. On the other hand, the 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 spatiotemporal sampling rate that can be achieved by the cluster. We also propose a simple analytical approach to optimizing the antennas beam width in order to improve the spatiotemporal sampling rate by maximizing the transport capacity of the network.