  We consider a relay-aided Slotted ALOHA solution for uplink random access for
an Optical Wireless Communications (OWC)-based Internet of Things (IoT). The
first phase of uplink, the one between IoT devices and the relays, is realized
using indoor OWC, while the second phase, between the relays and a base
station, represents the long-range RF transmission based on low-power wide area
network such as LoRaWAN and occurs outdoors. The throughput performance
dependence on the OWC and RF channel conditions is observed. The behavior of
the performance gain due to adding relays is highlighted and investigated under
different channel and traffic conditions.
