Spectrum Sharing in Cognitive Radio Systems

In this paper, we focus on a wireless flat fading channel in a Cognitive radio network composed of licensed users (primary) and unlicensed users (secondary). We propose a framework for analyzing the access strategy based on the received interference at the secondary receiver and analyzing the achievable capacity of the secondary under the average power and average interference constraints. The proposed approach to the spectrum sharing, based on the received interference at the secondary receiver, significantly reduces the system complexity. We categorize the spectrum sharing into two cases based on the maximum interference threshold. We obtain a critical system parameter to eliminate the interference threshold constraint.