MAC layer design in cognitive radio networks

The main focus of this thesis is to design and develop cognitive MAC protocols for various networks. Furthermore, we aim to explore the design tools, approaches and auxiliary systems that can be adapted to and applied in cognitive radio (CR) domain. In particular, we proposed a distributed spectrum access scheme for ad hoc CR networks (CRN) in which each secondary user (SU) acts in an altruistic way. The proposed access scheme improves CRN throughput compared to the selfish scheme that is mostly considered in the literature. Next, we propose a symbiotic operation of CRs and cognitive femtocells, in which SUs use the sensing outcome of the femto-BS and are charged accordingly. Addition of "cognitive" sensing to the femto-BS contributes to the discovery of spectrum holes and facilitates higher bandwidth at the femtocells compared to the conventional femto-BS. Currently, we focus on design and development of adaptive medium access control (MAC) protocol that considers various aspects of the operating environment (e.g. PU mobility) and the CR itself.