Secure resource allocation and dynamic spectrum access for polarization-based green cooperative cognitive radio networks

Abstract

We address secure communication for energy-harvesting (EH) based cooperative cognitive radio networks (CRNs), in which several EH secondary users (SUs) cooperate with one primary user (PU) for both data transmission and energy harvesting. To increase the amount of energy harvested by SUs while improving spectrum utilization, we suppose that SUs are equipped with orthogonally dual-polarized antennas. On the basis of this assumption, we put forward a polarization-based two-phase cooperative framework, where SU transmitters first harvest energy from the PU's radio frequency (RF) signals by using the power splitting technique, and then utilize the harvested energy to convey their own and the PU's data concurrently. Under this framework, we study secure resource allocation and dynamic spectrum access when SU receivers are untrusted, where each SU receiver may eavesdrop on the other SUs' confidential information. For this scenario, we investigate the joint allocation of relays, power splitting ratios, and powers as well as the dynamic spectrum access of SUs by using the Stackelberg game, with the aim to maximize each cooperative SU's secrecy rate while ensuring the PU's minimum rate requirement. Finally, we evaluate the performance of our proposed framework through numerical analyses.