Age of Information in Two-Hop Multicast Networks
Baturalp Buyukates, Alkan Soysal, Şennur Ulukuş · 2018 52nd Asilomar Conference on Signals, Systems, and Computers · 2018
We consider the age of information in a two-hop multicast network where there is a single source node sending time-sensitive updates to n2end nodes through n middle nodes. In the first hop, the source node sends updates to n middle nodes, and in the second hop each middle node relays the update packets that it receives to n end users that are connected to it. We study the age of information experienced by the end nodes, and in particular, its scaling as a function of n. We show that, using an earliest k transmission scheme, the age of information at the end nodes can be made a constant independent of n. In particular, the source node transmits each update packet to the earliest k1of the n middle nodes, and each middle node that receives the update relays it to the earliest k2out of n end nodes that are connected to it. We determine the optimum k1and k2stopping values for arbitrary shifted exponential link delays.