A Cooperative MAC with Efficient Spectrum Sensing Algorithm for Distributed Opportunistic Spectrum Networks

The spectrum scarcity has led to rethink in the current frequency spectrum usage and develop a new concept of wireless networking. Opportunistic Spectrum Networks (OSNs) have been considered as a promising solution to the problem of spectrum shortage. In this paper, in order to compensate for the need of complex hardware, a novel and efficient Medium Access Control (MAC) framework that integrates a kind of cooperative spectrum sensing method at the physical layer into a cooperative MAC protocol is developed for distributed OSNs considering the requirements of both the primary and secondary users. For the MAC framework, an innovative deterministic sensing policy called Allocated-group Sensing Policy (ASP) is proposed to identify the spectrum opportunities based on a dynamic ID numbering approach, and its effectiveness is demonstrated by comparison with two random sensing policies. Moreover, a computationally simple but efficient sensing algorithm is developed to assist each sensing user to identify the optimal number of channels to sense and the optimal sensing duration. It is demonstrated that the proposed cooperative MAC framework can efficiently achieve the ultimate goal of the OSNs even with only a small number of sensing users each equipped with a single cognitive radio transceiver.