Distributed diversity in ultrawide bandwidth wireless sensor networks

In this paper we consider a decentralized detection problem in ultrawide bandwidth (UWB) wireless sensor network (WSN). The system model assumes that all sensor nodes have established an ad-hoc network for sharing the information before sending the common message to the fusion center. The architecture is asynchronous and communication channels between the local sensors to the fusion center are subjected to fading and noise. Our communication strategy employs a UWB transmitted-reference (TR) signaling scheme. We first analyze the asymptotic performance of our communication strategy via the Chernoff bound and show that the upper bound on the probability of decision error at the fusion center decays exponentially with increasing number of nodes. Simple link budget analysis is given to demonstrate the need for distributed diversity in energy constrained large scale WSN. We also derive the required average transmission power per bit of each node to achieve a target BER at the fusion center and quantify the energy efficiency of our communication strategy.