  Integrating mobile edge computing (MEC) and wireless power transfer (WPT) has
been regarded as a promising technique to improve computation capabilities for
self-sustainable Internet of Things (IoT) devices. This paper investigates a
wireless powered multiuser MEC system, where a multi-antenna access point (AP)
(integrated with an MEC server) broadcasts wireless power to charge multiple
users for mobile computing. We consider a time-division multiple access (TDMA)
protocol for multiuser computation offloading. Under this setup, we aim to
maximize the weighted sum of the computation rates (in terms of the number of
computation bits) across all the users, by jointly optimizing the energy
transmit beamformer at the AP, the task partition for the users (for local
computing and offloading, respectively), and the time allocation among the
users. We derive the optimal solution in a semi-closed form via convex
optimization techniques. Numerical results show the merit of the proposed
design over alternative benchmark schemes.
