Distributed 'ring-around' sequential spectrum sensing for cognitive radio networks

In this paper we present a distributed spectrum sensing technique based on a ring-formulation of the cognitive radio (CR) nodes in a network. The CR nodes in a network form a logical ring based on a particular criteria and distributes the local spectrum sensing decisions along the ring in a sequential manner to the successive CR nodes. Considering this method, we eliminate the requirement for all the CR nodes to send/broadcast its local decisions to all the other CR nodes as in the traditional distributed detection method. Moreover, in our method all the CR nodes in the ring will have the spectrum sensing information from all the other nodes in the ring unlike the traditional sequential distributed-sensing technique (without the ring formation). We also consider the temporal behavior of the primary user modeled as a Poisson-Pareto burst process, and present two distributed sensing techniques based on the `ring-around¿ strategy for the energy based local detection method. We provide closed-form solutions for the detection and false alarm probabilities for the ring-around detection methods and present numerical results in a scenario with Rayleigh fading and AWGN.