An Iterative Method for Resource Leasing in Cognitive Radio Networks

Solutions for better spectrum utilization have widely been investigated in the past years. Recently, spectrum leasing has been proposed as a powerful technique for spectrum management in communication networks. In this paper, we propose a new leasing scheme in both time and frequency domains joint with cooperative communication for cognitive orthogonal frequency-division multiplexing (OFDM) systems in a network composed of a primary transmitter and some secondary users forming a cooperative relay network. In the proposed scheme, the primary user decides to lease a part of its available resources (time and frequency) to a group of relays, with the aim of increasing its link reliability. Two schemes, simple and intelligent, are studied for resource allocation. We show that the simple scheme which is more applicable has same result as the intelligent scheme in most of situations. An iterative negotiation between the primary and secondary networks is assumed in this process to find the optimal amount of available OFDM symbols as well as subcarriers that should be involved in the cooperation process. Simulation results show that the primary network can achieve a higher data rate using our proposed iterative cooperation process compared to the case where no cooperation is exploited. Besides, our simulation results show that the secondary users also may increase their quality of service in terms of their link achievable data rate, via this cooperation process.