Round Trip Times (RTTs): Comparing Terrestrial and LEO Satellite Networks

One of the potential advantages of Low Earth Orbiting (LEO) satellite constellation networks is the reduction in delay, which is critical for some services and applications. Theoretically, LEO satellite networks have a lower propagation delay when the endpoints are at distances longer than a few thousand km due to the higher propagation speed of radio transmission compared to fiber. However, the theoretical analysis makes assumptions about transmission paths that are not valid in all cases and does not account for other factors that influence delay, such as processing or queuing delays. Therefore, experimental studies are needed based on measurements and simulations. This paper presents the first comparison between real Round Trip Time (RTT) measurements on terrestrial networks and simulated RTTs on different LEO constellations. The results confirm the potential benefits of LEO constellations not only in reducing RTT values, but also in reducing their dispersion versus distance.