Peak Age of Information Distribution Bounds for Multi-Connectivity Transmissions

Transmission of packets over multiple wireless interfaces is an effective method to improve reliability and reduce the delay of Internet of Things (IoT) transmissions. In this context, Age of Information (AoI) has become a useful metric for many applications, measuring the freshness of the information available on a process that is measured by a remote sensor. In this work, we study the Peak Age of Information (PAoI) of an M/M/2 fork-join system, in which a sensor sends packets simultaneously over 2 separate queuing systems. The first packet to reach the receiver is considered as delivered. We derive lower and upper bounds on the PAoI for systems with finite and infinite buffers based on a low-traffic approximation, and show that the bounds are very tight at the optimal working point, so that the best rate derived from the bounds is very close to the optimum.