Title: Status updates through M/G/1/1 queues with HARQ,
Abstract: We consider a system where randomly generated updates are to be transmitted
to a monitor, but only a single update can be in the transmission service at a
time. Therefore, the source has to prioritize between the two possible
transmission policies: preempting the current update or discarding the new one.
We consider Poisson arrivals and general service time, and refer to this system
as the M/G/1/1 queue. We start by studying the average status update age and
the optimal update arrival rate for these two schemes under general service
time distribution. We then apply these results on two practical scenarios in
which updates are sent through an erasure channel using (a) an infinite
incremental redundancy (IIR) HARQ system and (b) a fixed redundancy (FR) HARQ
system. We show that in both schemes the best strategy would be not to preempt.
Moreover, we also prove that, from an age point of view, IIR is better than FR.