  In this paper, we consider wireless powered communication networks which
could operate perpetually, as the base station (BS) broadcasts energy to the
multiple energy harvesting (EH) information transmitters. These employ "harvest
then transmit" mechanism, as they spend all of their energy harvested during
the previous BS energy broadcast to transmit the information towards the BS.
Assuming time division multiple access (TDMA), we propose a novel transmission
scheme for jointly optimal allocation of the BS broadcasting power and time
sharing among the wireless nodes, which maximizes the overall network
throughput, under the constraint of average transmit power and maximum transmit
power at the BS. The proposed scheme significantly outperforms "state of the
art" schemes that employ only the optimal time allocation. If a single EH
transmitter is considered, we generalize the optimal solutions for the case of
fixed circuit power consumption, which refers to a much more practical
scenario.
