The problem of reducing the age-of-information has been extensively studied in single-hop networks. In this paper, we minimize the age-of-information in general multihop networks. If the packet transmission times over the network links are exponentially distributed, we prove that a preemptive Last Generated First Served (LGFS) policy results in smaller age processes at all nodes of the network (in a stochastic ordering sense) than any other causal policy. In addition, for arbitrary distributions of packet transmission times, the non-preemptive LGFS policy is shown to minimize the age processes at all nodes among all non-preemptive work-conserving policies (again in a stochastic ordering sense). It is surprising that such simple policies can achieve optimality of the joint distribution of the age processes at all nodes even under arbitrary network topologies, as well as arbitrary packet generation and arrival times. These optimality results not only hold for the age processes, but also for any non-decreasing functional of the age processes. • We consider a general multihop network where the update packets do not necessarily arrive to the gateway node in the order of their generation times. We prove that, if the packet transmission times over the network links are exponentially distributed, then for arbitrary arrival process, network topology, and buffer sizes, the preemptive LGFS policy minimizes the age processes at all nodes in the
Recently, we generalized our results to multihop networks in REF , where we proved that age-optimality is achievable in multihop networks with arbitrary packet generation times, packet arrival times, and general network topologies.
Age-optimal information updates in multihop networks
2017 IEEE International Symposium on Information Theory (ISIT)
2017 IEEE International Symposium on Information Theory (ISIT)
Computer Science Mathematics