  In this paper, we consider a wireless communication network with a
full-duplex hybrid access point (HAP) and a set of wireless users with energy
harvesting capabilities. The HAP implements the full-duplex through two
antennas: one for broadcasting wireless energy to users in the downlink and one
for receiving independent information from users via
time-division-multiple-access (TDMA) in the uplink at the same time. All users
can continuously harvest wireless power from the HAP until its transmission
slot, i.e., the energy causality constraint is modeled by assuming that energy
harvested in the future cannot be used for tranmission. Hence, latter users'
energy harvesting time is coupled with the transmission time of previous users.
Under this setup, we investigate the sum-throughput maximization (STM) problem
and the total-time minimization (TTM) problem for the proposed multi-user
full-duplex wireless-powered network. The STM problem is proved to be a convex
optimization problem. The optimal solution strategy is then obtained in
closed-form expression, which can be computed with linear complexity. It is
also shown that the sum throughput is non-decreasing with increasing of the
number of users. For the TTM problem, by exploiting the properties of the
coupling constraints, we propose a two-step algorithm to obtain an optimal
solution. Then, for each problem, two suboptimal solutions are proposed and
investigated. Finally, the effect of user scheduling on STM and TTM are
investigated through simulations. It is also shown that different user
scheduling strategies should be used for STM and TTM.
