On the performance of single ring law based sensing approaches for opportunistic spectrum access

Multiple antenna systems are becoming increaingly prominent startig from 4G systems to the evolving 5G systems. During the course of these system deployments, spectrum scarcity has been a well prevailing problem. In this regard, opportunistic spectrum access schemes have been developed, which adopt periodic sensing approaches to detect the presence of the primary user and thereby allow efficient spectrum utilization by secondary users. Extension of spectrum sensing approaches to multiple antenna systems require a proper detection framework. The recent formulations of large random matrices and associated single ring law (SRL) for signal detection have been validated only for massive antenna systems. Further, its detection performance with respect to existing sensing approaches has not been studied so far. In this paper, first we present a detection framework suitable for any multiple antenna system. Introducing modifications to this framework so as to reduce the number of computations, we explore the suitability of single ring law (SRL) based spectrum sensing in comparison to other approaches. Finally, we propose a hybrid dual-stage sensing approach, which renders better detection performance than the existing ones. Using system simulations, under two different cases of sparse channel environments, namely multiple channels having exact common support and approximate common support, the efficacy of the proposed approach is demonstarted using detection probability versus signal to noise ratio (SNR) plots.