Fundamental Bounds on the Age of Information in General Multi-Hop Interference Networks
Shahab Farazi, Andrew G. Klein, Donald R. Brown · 2019
This paper studies the “age of information” of status updates in a general multi-source multi-hop wireless network with time slotted transmissions and general interference constraints. Specifically, the scenario considered in this paper assumes that each node in the network is both a source and a monitor of information and that all nodes wish to receive fresh status updates from all other nodes in the network. Lower bounds for the instantaneous peak and average age of information are derived for three interference models using properties of each interference model's family of feasible activation sets. These bounds generalize prior results derived for the “global” interference model where only one node transmits in each time slot. Achievability results are presented through the development of explicit schedules for ring networks in three specific interference models: (i) global interference, (ii) interference free, i.e., all nodes can transmit simultaneously without interference, and (iii) topologically-dependent interference where multiple nodes transmit simultaneously if they share no one-hop neighbors. Numerical examples are presented to quantify the gap between the achieved age and the bounds.