Jointly optimal downlink/uplink design for wireless powered networks

We jointly optimize the downlink and the uplink of a wireless powered communication network and improve their rates, by utilizing corresponding priority weights. Two communication protocols are taken into account, namely time division multiple access (TDMA) and non orthogonal multiple access (NOMA). The considered multidimensional non-convex optimization problems are transformed into the equivalent convex ones and can be solved with low complexity. Simulations results illustrate that: i) a relatively high downlink rate can be achieved, while the required energy is harvested by the users for the uplink, ii) NOMA in the downlink is a more appropriate option, when a high downlink rate is desired or when the users are asymmetrically located around the base station.