Abstract : In this paper, we examine the Age of Information(AoI) of a source sending status updates to a monitor througha queue operating under the Processor Sharing (PS) discipline.While AoI has been well studied for various queuing models andpolicies, less attention has been given so far to the PS discipline.We first consider M/M/1/2 queue with and without preemptionand provide closed-form expressions of the average AoI in thiscase. We overcome the challenges of deriving the AoI expressionby employing the Stochastic Hybrid Systems (SHS) tool. We thenextend the analysis to the M/M/1 queue with one and two sourcesand provide numerical results for these cases. Our results showthat PS can outperform the M/M/1/1* queue in some cases.
Index terms : Age of Information , Processor Sharing Queues , Stochastic Hybrid System