Effective capacity optimization for cognitive radio network based on underlay scheme in gamma fading channels

As fundamental spectrum sensing and access techniques in cognitive radio networks (CRN) matured in last decade, the satisfaction of quality-of-service (QoS) demands for cognitive users (CU) has attracted lots of research attention. In this paper, we study how the delay QoS requirements affect the dynamic spectrum access (DSA) strategy on network performance. We first treat the delay-QoS in interference constrained cognitive radio network by applying the effective capacity theory, focusing on the dominant DSA scheme: underlay. We show that the roles that the transmit-power/interference-power constraints play in optimizing CUs´ throughput vary significantly with the delay QoS requirements. Performance analysis and numerical evaluations are provided to demonstrate the effective capacity of CRN based on underlay scheme, taking into consideration the impact of delay QoS requirements and other related parameters.