Online Spectrum Allocation Mechanism

Without the synchronization of allocation periods, it is impossible to run the spectrum sharing mechanism in an offline manner. Thus, in this chapter, we investigate the online spectrum allocation problem in CR networks with uncertain activities of both PUs and SUs. In this system model, there is a PBS who owns multiple licensed radio channels and is responsible to protect PUs’ spectrum usages. At the same time, the PBS also runs an online auction to lease its idle channels to SUs who request and access spectrum on the fly. By considering a more practical situation that the PBS has no a priori information of PUs’ activities, the PBS may suffer a great penalty if it is only eager to improve its potential auction revenue while ignoring its own PUs’ spectrum usages. On the other hand, if the PBS reserves channels excessively to completely protect its own PUs, it may lose economic profits from the spectrum auction. To balance the penalties introduced by incomplete services for PUs and the auction profits from granted SUs’ spectrum requests, we present a new approach, called virtual online double spectrum auction (VIOLET) mechanism [1]. In this mechanism, the concept of virtual spectrum sellers is introduced to describe the channel uncertainties. The well-designed online admission and pricing scheme of VIOLET can ensure non-deficit utility of the PBS while resisting mendacious behaviors from selfish SUs. Theoretical analyses prove that the VIOLET mechanism is economic robust in terms of budget-balance, individual rationality, and incentive compatibility. In addition, simulation results show that the VIOLET mechanism can improve the utility of the PBS, enhance spectrum utilization, and achieve better satisfaction of SUs.