Contract-based cooperative spectrum sharing in cognitive radio networks

Cognitive radio is a promising paradigm to improve utilization of the radio frequency spectrum. In this work, we study a contract-based mechanism for sharing spectrum among primary licensed user (PU) and secondary unlicensed users (SUs). We assume that SUs cooperate in PU signal transmission. However, there are some challenges that the PU should overcome. First, considering the fact that nodes are selfish, brings the necessity of a reimbursement method to remunerate the helping SUs. Second, SU hides its private channel state information from other nodes, which results in asymmetry of information. The proposed contract-theory based framework provides a solution for spectrum allocation under asymmetric channel information. We compare the performance results with a benchmark scenario and we show through simulation results that both the PU and the SU gain positive revenue.