Power Allocation Scheme and Performance Analysis for Multiuser Underlay Full-Duplex Cognitive Radio Networks With Energy Harvesting

This paper introduces a comprehensive wireless energy harvesting model applied for multiple secondary users (SUs) in full-duplex cognitive radio networks. In this proposed model, SUs harvest energy from a hybrid base station (HBS), in addition to the primary user (PU) network on the downlink and transmit their data on the uplink. The opportunistic user selection scheme is employed in the SU network to achieve a better SU performance. Considering the underlay spectrum sharing paradigm, the total SU transmitted powers are limited to the maximum allowable PU interference threshold. Moreover, the proposed SU system suffers from self-interference from the transmitting antenna of the HBS and co-channel interference from the PU transmitter. Closed-form expressions for the SU system outage probability, average symbol error probability, and ergodic capacity are derived. Obtained exact expressions are then simplified to their asymptotic results in the high signal-to-noise-ratio regime. Based on these results, a power allocation optimization problem is formulated to reduce the SU outage probability under the constraints of performance indices. Computer-aided numerical and simulation work is performed to validate the exact expressions.