A$^3$L-FEC: Age-Aware Application Layer Forward Error Correction Flow Control

Abstract: Age of Information (AoI) is a metric and KPI that has been developed for measuring and controlling data freshness. Optimization of AoI in a real-life network requires adapting the rate and timing of transmissions to varying network conditions. The vast majority of previous research on the control of AoI has been theoretical, using idealized models that ignored certain implementation aspects. As such, there is still a gap between the research on AoI and real-world protocols. In this paper we present an effort toward closing this gap by introducing an age-aware flow control algorithm. The algorithm, Age-Aware Application Layer Forward Error Correction (A$^3$L-FEC), is a packet generation mechanism operating on top of the User Datagram Protocol (UDP). The purpose is to control the peak Age of the end-to-end packet flow, specifically to reduce the rate of so-called "Age Violations," i.e., events where the peak age exceeds a given threshold. Evaluations in Mininet-WiFi and MATLAB indicate that A$3$L-FEC reduces age violations compared to two related protocols in the literature, namely TCP-BBR and ACP+.