SWIPT-aided uplink in hybrid non-orthogonal multiple access

In this paper, we propose a novel wireless-powered hybrid (downlink and uplink) NOMA system to facilitate uplink NOMA transmission on the basis of harvested energy from radio frequencies. Particularly, this scheme enables the users to maintain distinguished power levels in communicating back to the source utilising NOMA, hence allowing source to extract received messages successfully. By assuming that the two users are located at different locations, analytical expressions of the outage probabilities of the users involved in this scheme are derived. Monte Carlo simulations are performed to validate the accuracy of the developed analytical model. It is clear from the results that wireless power transfer can be used successfully in uplink NOMA transmission in case when the users are running out of power, providing successful communication between users and the source.