  In this article, we consider a random access scheme for an indoor Internet of
Things (IoT) framework that uses optical wireless communication (OWC). We focus
on a Slotted ALOHA (SA)-based solution where a number of OWC IoT users contend
to send data to a central OWC receiver. In any given slot, and for a randomly
selected active user, we consider the reliability of decoding the user's data
packet at the receiver. This is done by deriving the
signal-to-noise-and-interference-ratio (SINR) statistics from a randomly chosen
user and evaluating the probability that the user's SINR is below a given
threshold. By placing our analysis in the context of an indoor OWC IoT uplink
setup, and employing the standard OWC channel model, we investigate the
trade-offs between the reliability and the OWC system parameters such as the
cell area or the transmitter's semi-angle. We obtain valuable insights into the
design of an SA-based random access solution for a typical indoor OWC cell.
