Adaptive Spectrum Leasing with Secondary User Scheduling in Cognitive Radio Networks

In this paper, an adaptive spectrum-leasing scheme is proposed for multiuser cognitive radio networks. Based on two-path successive relaying and decode-and-forward protocols, each cognitive user intelligently switches the spectrum leasing protocol to cooperate in the primary data transmission. As a reward, the spectrum is then leased to the cognitive user for its own data transmission. For given m cognitive users, the best one that can achieve the largest secondary rate while satisfying primary rate target is scheduled for the spectrum leasing. It is shown that the cooperative diversity gain of m+1 is achieved for the primary system and the selection diversity gain of m is obtained for the secondary system. Moreover, multiuser diversity of secondary system is studied and the throughput scales as log(log m) when m is large. Performance results are provided to verify the efficiency of the proposed adaptive spectrum leasing scheme compared with the decode-and-forward based scheme and two-path successive relaying based scheme.