  The emerging intelligent reflecting surface (IRS) technology introduces the
potential of controlled light propagation in visible light communication (VLC)
systems. This concept opens the door for new applications in which the channel
itself can be altered to achieve specific key performance indicators. In this
paper, for the first time in the open literature, we investigate the role that
IRSs can play in enhancing the link reliability in VLC systems employing
non-orthogonal multiple access (NOMA). We propose a framework for the joint
optimisation of the NOMA and IRS parameters and show that it provides
significant enhancements in link reliability. The enhancement is even more
pronounced when the VLC channel is subject to blockage and random device
orientation.
