A Novel Polarization Enabled Full-Duplex Hybrid Spectrum Sharing Scheme For Cognitive Radios

Abstract

This letter proposes a novel polarization enabled full-duplex hybrid spectrum sharing method for cognitive radios. The proposed method enables the secondary users (SUs) continuously sense the primary users (PUs) states, learn PUs’ polarization characteristics and accordingly adapt SUs’ polarizations to access the licensed spectrum. When PUs are detected, SUs transmit using a polarization in the null space of PUs’ polarization space. When the spectrum is detected idle, SUs transmit using another polarization that achieves the maximal secondary throughput. As a general case, of the full-duplex interweave and full-duplex underlay spectrum sharing schemes, the proposed method improves the secondary throughput. With the merits of using polarization, the proposed method also takes the advantage of interference robustness to PUs. Simulation results show that the proposed method guarantees sufficiently small collision ratio to PUs while PUs’ interference performance and secondary throughput are largely improved in comparison to the traditional schemes.