Peak Age of Information in a Multicasting Network

With the increasing number of real-time monitoring networks, the relevance of the transmitted information has become an important characteristic. Examples of such networks include sensor networks that measure and transmit atmospheric pressure, temperature and other environmental parameters, unmanned vehicles that require up-to-date information about speed, position and acceleration, and other systems. In all of these applications, information becomes obsolete over time and loses its value. In this paper, a single-layer multicasting network with tree topology is constructed. A source generates updates containing information about the state of the remote system and sends them to the root node, which transmits them to n end nodes. The transmission is carried out using a stopping scheme with threshold k. The point of the stopping scheme is to stop transmitting the update to the remaining n − k nodes after the first k nodes acknowledge its receiving. The peak age of information (AoI) at the end nodes is of interest. The analysis is carried out using mathematical and simulation modelling. Approximate and exact formulas for the mean peak AoI at the end nodes are obtained, which match the simulation results. The analysis shows that the use of stopping scheme not only improves the efficiency of radio resource utilisation by reducing the number of transmissions, but also reduces the AoI at the end nodes.