A Notion of Diversity Order in Distributed Radar Networks

We introduce the notion of diversity order in distributed radar networks. Our long-term goal is to analyze the trade-off between distributed detection and centralized detection using co-located antennas. In contrast with the asymptotically high Signal-to-Noise Ratio (SNR) definition in wireless communications, we define the diversity order of a distributed radar network as the slope of the probability of detection (P_D) versus SNR curve at P_D = 0.5. In this paper we restrict our analysis to noise-limited systems. We evaluate the diversity order of fully distributed systems, and prove that for the OR rule, the gain in diversity is only logarithmic in the number of distributed sensors, denoted K. The AND rule does not lead to any gain in diversity order. We finally present some recent results, and provide preliminary analysis regarding the characterization of a Diversity-Multiplexing tradeoff in distributed radar detection.