  We study the multi-user massive multiple-input-single-output (MISO) and focus
on the downlink systems where the base station (BS) employs hybrid
analog-digital precoding with low-cost 1-bit digital-to-analog converters
(DACs). In this paper, we propose a hybrid downlink transmission scheme where
the analog precoder is formed based on the SVD decomposition. In the digital
domain, instead of designing a linear transmit precoding matrix, we directly
design the transmit signals by exploiting the concept of constructive
interference. The optimization problem is then formulated based on the geometry
of the modulation constellations and is shown to be non-convex. We relax the
above optimization and show that the relaxed optimization can be transformed
into a linear programming that can be efficiently solved. Numerical results
validate the superiority of the proposed scheme for the hybrid massive MIMO
downlink systems.
