Uplink resource allocation for cognitive radio systems: QAM-OFDM or OQAM-OFDM?

Daily increasing demand for new wireless services with higher data rate and QoS level makes the upgrade of the physical layer modulation techniques inevitable. OFDMA is a common multiple access multicarrier modulation technique that is usually used in cognitive radio (CR) systems. Recently, a new technology, filter bank multicarrier system (FBMC) has been introduced to provide multiple access systems with filter banks. Therefore, it seems that OFDMA is not always the best candidate for CR systems. FBMC system is an evolutionary scheme with some advantages over the common-used OFDM multicarrier systems. This technology uses filter banks to produce independent subcarriers with better spectrum efficiency and resolutions in comparison with OFDM subcarriers. In this paper, by using an idea related to this modulation technique, we propose an uplink radio resource allocation algorithm in which fairness issue is also considered. Basically, we have focused on total capacity enhancement of a CR network using FBMC modulation. In order to better illustrate the efficiency FBMC modulation technique in future CR systems, we have also enhanced the proposed resource allocation algorithm for OFDM and FBMC based CR system in the case MIMO communications.