Simultaneous information and power transfer for relay-assisted cognitive radio networks

Simultaneous information and power transfer (SIPT) potentially offers great convenience to prolong the lifetime of energy-constrained nodes in wireless networks. Moreover, the integration of cognitive radio and relay transmission has emerged as a powerful technique for improving spectrum utilization and enhancing throughput. In this paper, we consider a cognitive amplify-and-forward (AF) relaying network, where the relay secondary user (SU) forwards the source information to the destination with the energy harvested from the radio-frequency (RF) signal, aiming at maximizing the throughput by a deadline of N slots. Supported by a proposed SIPT-enabled cognitive relay architecture, our problem is formulated and approximated with its upper bound. A suboptimal joint management algorithm based on the solution of the upper bound is developed, whose superiority is validated through numerical simulations. The results indicate that the proposed algorithm performs closely to the optimal solution, and yields a significant gain compared to the separate management algorithm.