Capacity analysis for secondary user in cognitive radio network

In this paper, we discuss three dynamic spectrum assignment schemes: Random Spectrum Assignment, Non- Random Spectrum Assignment and Reservation based Non- Random Spectrum Assignment. A general definition of capacity for secondary user is given. By using quasi birth and death theory, we derive the closed-form solution of secondary capacity and analyze the relationships between system parameters and capacity. Based on analysis, we get an assertion that channel reservation always leads to the decrease of capacity.