Opportunistic interference alignment networks for simultaneous wireless information and power transfer through user selection

Interference alignment (IA) is an emerging technology for interference management. However, the received signal-to-interference-plus-noise ratio (SINR) may decrease in IA. Opportunistic IA (OIA) schemes can provide more opportunities for the users to access the network and improve the performance; nevertheless, the unselected users remain idle, which is a waste of resource. Thus in this paper, simultaneous wireless information and power transfer (SWIPT) in OIA networks is studied. As the unselected users in OIA networks can be treated as energy harvesting (EH) terminals, an OIA user selection (OIAUS) algorithm is proposed to optimize the SWIPT performance through user selection, according to the information-transmission (IT) and EH performance as well as the requirements of users. To further reduce the complexity, a random complexity-reduced OIAUS algorithm is designed to make a tradeoff between performance and complexity. Simulation results are presented to show the effectiveness of the proposed algorithms.