  The omnipresence of IoT devices in Industry 4.0 is expected to foster higher
reliability, safety, and efficiency. However, interconnecting a large number of
wireless devices without jeopardizing the system performance proves
challenging. To address the requirements of future industries, we investigate
the cross-layer design of beamforming and scheduling for layered-division
multiplexing (LDM) systems in millimeter-wave bands. Scheduling is crucial as
the devices in industrial settings are expected to proliferate rapidly. Also,
highly performant beamforming is necessary to ensure scalability. By adopting
LDM, multiple transmissions can be non-orthogonally superimposed. Specifically,
we consider a superior-importance control multicast message required to be
ubiquitous to all devices and inferior-importance private unicast messages
targeting a subset of scheduled devices. Due to NP-hardness, we propose
BEAMWAVE, which decomposes the problem into beamforming and scheduling. Through
simulations, we show that BEAMWAVE attains near-optimality and outperforms
other competing schemes.
