Effective capacity optimization based on overlay cognitive radio network in gamma fading environment

Traditionally, the frequency spectrum is licensed to users who have the exclusive right to access the allocated band. However, an unlicensed (cognitive) user may share a frequency band with a licensed (primary) owner as long as the interference is below a certain threshold. This makes capacity analysis a critical important issue in these networks. Lots of research on cognitive radio (CR) networking have now focused on the satisfaction of quality-of-service (QoS) demands for cognitive users (CU). In this paper, we study how the delay QoS requirements affect the dynamic spectrum access (DSA) strategy on network performance. We treat the delay-QoS in interference constrained cognitive radio network by applying the effective capacity concept, focusing on one of the dominant DSA schemes: overlay. Optimal power allocation scheme is obtained. This scheme considers the transmit-power/interference-power constraints and the primary user activity. Performance analysis and numerical evaluations demonstrate the proposed effective capacity optimization on the DSA overlay scheme. The impact of delay QoS requirements and other related parameters are evaluated as well.