چكيده به لاتين
Abstract
Cognitive radio has been proposed as the means for unlicensed secondary users to dynamically access the licensed spectrum held by primary users to increase the efficiency of spectrum utilization. Recently, a new paradigm termed cooperative cognitive radio networks (CCRNs) has been advocated. In CCRNs, PUs recruit some SUs to cooperatively relay the primary traffic and in return grant them a portion of the channel access time. Not only can the PUs enjoy a significant throughput gain due to the cooperation, the SUs obtain opportunities to transmit their own data. Since, exploiting cooperative communication in order to enhance performance of cognitive radio network has drawn noticeable attention. Therefore, multiple-input-multiple-output (MIMO) technique makes it possible to improve information achievable data rates via by simultaneous transmission independent information sequences over multiple antennas. In this dissertation, a spectrum leasing model within the framework of game theory is proposed for a multiuser multiple-input-multiple-output (MIMO) cooperative cognitive radio network (CCRN), where the transmitters and receivers have multiple antennas. Based on cooperation-based spectrum leasing model, primary user may be willing to lease its bandwidth for a fraction of time to secondary users in exchange for tailored revenue. On the other hand, selected secondary users pay rents proportional to their transmit powers which are achieved as outcoms of secondary non-cooperative maximization. Non-cooperative secondary games are set up for two different utility functions which are defined as the difference between the achievable transmission rate and the cost of transmitted energy and also energy efficiency. Distributed algorithms are presented in order to converge to the unique Nash equilibrium (NE). Moreover, interference cancellation is applied into secondary network in order to improve the utilities of both primary link and secondary network. Eventually, the proposed spectrum leasing model is generalized for a cooperative cognitive radio network with common secondary receiver. Performance results are provided to verify the improvement of the proposed scheme for both primary and secondary networks compared with the non-cooperative communication and single antenna spectrum leasing.
Keywords-Cognitive Radio, Spectrum Leasing, Cooperative Communication, Multiple Antennas.
