  With the rapid expansion of the Internet of Things, the efficient sharing of
the wireless medium by a large amount of simple transmitters is becoming
essential. Scheduling-based solutions are inefficient for this setting, where
small data units are broadcast sporadically by terminals that most of the time
are idle. Modern random access has embraced the challenge and provides suitable
slot-synchronous and asynchronous multiple access solutions based on
replicating the packets and exploiting successive interference cancellation
(SIC) at the receiver. In this work, we focus on asynchronous modern random
access. Specifically, we derive an analytical approximation of the performance
of irregular repetition ALOHA (IRA) in the so-called error floor region.
Numerical results show the tightness of the derived approximation under various
scenarios.
