DISTRIBUTED BEAMFORMING FOR WIRELESS SENSOR NETWORKS WITH RANDOM NODE LOCATION

Due to the unsupervised nature of wireless sensor networks (WSNs), intensive communications are required among the selected nodes to reach a consensus and synchronize prior to entering a distributed beamforming (DBF) procedure. Therefore, a, sensible approach to select the nodes should not only take into account the required beampattern, but also should aim to preserve the inter-node connectivity and the network energy. We show for a uniformly distributed WSN that when the nodes are selected from a ring of proper radii, the resulting beampattern mainlobe is narrower compared to that of the classical DBF technique proposed in [1]. At the same time, our proposed technique may preserve a substantial amount of network energy and reduce the probability of network dis-connectivity. Directivity of the proposed DBF technique is analyzed and an extension of the technique to a multi-ring case is presented. It is shown that the sidelobe peaks can be considerably decreased if the nodes are selected from multiple concentric rings.