Wireless information and energy transfer: tradeoff for fair resource allocation

In this paper, we study two schemes for the fair resource allocation in wireless powered communication networks (WPCNs): a non-orthogonal multiple access (NOMA) scheme, and a proportional fair (PF) scheduling scheme. The considered WPCN consists of a base station (BS) that broadcast radio frequency (RF) energy over the down link, and energy harvesting users (EHUs). If NOMA is employed, all EHUs concurrently transmit information over the up link with successive interference cancellation employed at the BS. If PF scheduling is employed, a single EHU is selected for up link transmission in each frame. For both schemes, we arrive at optimal allocations for the BS transmit power and the time sharing between up link and down link transmissions that maximize the up link sum-rate, while maintaining high level of system fairness. For the PF scheme, we also derive the optimal scheduling policy. Compared to the state-of-the art schemes based upon time division multiple access (TDMA), both schemes significantly improve the system fairness at the expense of minor (or nonexistent) rate degradation. (author)