A hybrid spectrum sharing approach in cognitive radio networks

In this paper, we propose a hybrid spectrum sharing approach in cognitive radio networks. If the primary network satisfies the required quality of service (QoS), an underlay approach can be applied for the secondary network. Otherwise, the secondary network must help primary network obtain the QoS and hence it must operate on overlay mode. We also derive the closed-formed expressions of the outage probability for the secondary network over Rayleigh fading channels. Monte-Carlo simulations are then presented to verify our derivations.