Distributed MAC for connectivity maximization of interference limited un-coordinated DSA networks

In this paper, we propose a medium access control (MAC) protocol to maximize the connectivity for an un-coordinated secondary dynamic spectrum access network under the signal to interference and noise ratio (SINR) regime. We use concepts from percolation theory to obtain the optimal deployment density for secondary nodes. We argue that the optimal connectivity under the SINR regime can be improved if a fraction of the nodes transmit at a given time. Thus, the proposed MAC is based on distributed Time Division Multiple Access (TDMA) where all nodes randomly choose a time slot to transmit on, a phenomenon similar to the Poisson blinking model. We find the optimal number of slots for the super-frame that includes the sensing, contention, and transmission phases. The performance of the proposed MAC is evaluated via simulations. We show how the proposed MAC adaptively adjusts the super-frame as the density of secondary varies. We also show the connectivity and throughput achieved for various network settings¹.