  This letter investigates the employment of vector-perturbation (VP) precoding
to convey simultaneously information and energy in multiple-user multiple-input
single-output (MU-MISO) downlink channel. We show that the conventional VP in
addition to the information capacity benefits that provides to linear channel
inversion techniques, it enhances the harvested energy at the receivers due to
the extended symbol constellation. To further boost harvesting performance, the
proposed modified VP technique (named VP-EH) designs the VP integer offsets in
order to maximize the delivered power. The proposed scheme incorporates an
integer least square problem to find the closest lattice point to a point which
is given by a Rayleigh quotient optimization problem. Finally, a convex
combination between conventional VP and VP-EH is proposed to achieve a
trade-off between maximizing information or energy. Theoretical and simulations
results validate that VP is a promising technique to simultaneously convey
information and energy in MU-MISO systems.
