Non-Cash Auction for Spectrum Trading in Cognitive Radio Networks: A Contract Theoretical Model with Joint Adverse Selection and Moral Hazard

摘要

In cognitive radio networks (CRNs), spectrum trading is an efficient way forsecondary users (SUs) to achieve dynamic spectrum access and to bring economicbenefits for the primary users (PUs). Existing methods requires full paymentfrom SU, which blocked many potential "buyers", and thus limited the PU'sexpected income. To better improve PUs' revenue from spectrum trading in a CRN,we introduce a financing contract, which is similar to a sealed non-cashauction that allows SU to do a financing. Unlike previous mechanism designs inCRN, the financing contract allows the SU to only pay part of the total amountwhen the contract is signed, known as the down payment. Then, after thespectrum is released and utilized, the SU pays the rest of payment, known asthe installment payment, from the revenue generated by utilizing the spectrum.The way the financing contract carries out and the sealed non-cash auctionworks similarly. Thus, contract theory is employed here as the mathematicalframework to solve the non-cash auction problem and form mutually beneficialrelationships between PUs and SUs. As the PU may not have the fullacknowledgement of the SU's financial status, nor the SU's capability in makingrevenue, the problems of adverse selection and moral hazard arise in the twoscenarios, respectively. Therefore, a joint adverse selection and moral hazardmodel is considered here. In particular, we present three situations wheneither or both adverse selection and moral hazard are present during thetrading. Furthermore, both discrete and continuous models are provided in thispaper. Through extensive simulations, we show that the adverse selection andmoral hazard cases serve as the upper and lower bounds of the general casewhere both problems are present.