Utility-based cooperative spectrum leasing scheme for CR networks with hybrid energy supplies

As cognitive radio (CR) technologies developed, cooperative CR networks (CCRNs) have become a potential way to increase the spectrum efficiency. Moreover, as the authors face the problem of energy shortage nowadays, energy harvesting (EH) is considered to be an effective method to alleviate this problem. However, with fitful and random energy arrivals, the energy harvested from natural energy source cannot guarantee satisfactory quality of service in EH networks. Hybrid energy supplies system has emerged as a promising way to solve unstable power supply problems, which mean that the communication terminals in these networks are powered by both fixed power supply and harvested energy. In this study, they propose a novel utility-based cooperative spectrum leasing scheme for CCRNs with hybrid energy supplies. The secondary user (SU) is a cooperative relay powered largely by harvested energy extracted from the radio-frequency signal of the primary user (PU). In this way, SU can shorten the primary data transmission period, and then win the access opportunities for secondary data transmission. They formulate this model as a Stackelberg game. In such a scenario, the PU intends to enhance its revenue and save energy by cooperating with the SU, while the SU tries to improve throughput and minimise the fixed energy consumption. The Stackelberg equilibrium for the proposed scheme is analysed. The experimental results show that the utility of both PU and SU can be improved under this scheme.