QoS Driven Throughput Performance Analysis of Secondary User in Cognitive Radio Networks

In this paper, based on the effective capacity theory, we identify the maximal arrival rate of secondary user that an arbitrary ON/OFF primary channel can sustain, in the presence of sensing errors. We find that, the arrival rate of secondary user with statistical QoS requirement, is limited by both the effective capacity provided by primary channel, and the packet collision probability constraint of primary user. In general, the above two constraints result in unequal arrival rates, exhibiting different impacts on spectrum utilization. Based on this observation, two spectrum utilization approaches, i.e., η-probability random access and sensing parameter adjustment, respectively, are proposed to fully utilize the transmission opportunities, depending on whether the sensing parameters could be adjusted or not. In specific, the η-probability random access approach reserves more transmission opportunities for other secondary users, which increases network throughput, while sensing parameter adjustment approach yields improved arrival rate for specific secondary user. Performances of the proposed approaches are validated by numerical results.