Age of information in multihop multicast networks
Baturalp Buyukates, Alkan Soysal, Şennur Ulukuş · Journal of Communications and Networks · 2019
We consider the age of information in a multihop multicast network where there is a single source node sending timesensitive updates to nLend nodes, and L denotes the number of hops. In the first hop, the source node sends updates to n first-hop receiver nodes, and in the second hop each first-hop receiver node relays the update packets that it has received to n further users that are connected to it. This network architecture continues in further hops such that each receiver node in hop I is connected to n further receiver nodes in hop ℓ + 1. 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 in each hop, 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 first-hop nodes, and each first-hop node that receives the update relays it to the earliest k2out of n second-hop nodes that are connected to it and so on. We determine the optimum k1stopping value for each hop I for arbitrary shifted exponential link delays.