Delay Tolerant Networking Helps Reducing Age of Information Under Intermittent Connectivity

Kurzfassung

We consider a task-oriented communication between a source and destination for timely status reporting of a monitored system. In spite of a main requirement of low latency, the direct link is affected by intermittent connectivity, which may hinder information freshness, quantified through age of information (AoI). However, the source can leverage delay-tolerant networking (DTN) among other peer nodes. These, in turn, relay the content to the end point, possibly through some similar procedure of spreading the content of interest throughout the entire DTN component. After finding a closed-form expression and a tight asymptotic bound for the service time, we are able to reframe our findings in the context of queueing theory. Specifically, we consider an M/G/1* queue with the average service time given by our result for the delivery time through the DTN. We show that the relay of information through the DTN is able to counteract problems due to intermittent connectivity, reducing the delivery time by a factor ln(N)/N. Concerning the resulting average AoI, a proper balance is present between increasing the sampling frequency and increasing the number of nodes in the DTN, which is also discussed.