Improving Efficiency and Reliability in Information Offloading for LEO Satellite Networks by Intersatellite Communication Techniques

Abstract

The task of offloading packets in low earth orbit satellite networks in an Internet of Things (IoT) cluster context is often affected by excessive energy consumption, frequent loss of data packets in the medium access, limited visibility time with the ground station, and limited resources available to the satellites. Intersatellite communication (ISC) techniques have been introduced to address these challenges. However, these techniques require high technical and strategic development to meet the requirements of the end users. In this regard, four strategies are proposed: Brief (which eliminates all redundancy); Balanced (which eliminates the redundancy but keeps the amount of information for each satellite balanced); Redundancy (which includes all the information collected on each satellite); and Coded (which provides redundancy through information coding). Our techniques are to exchange signaling or data packets between satellites via ISC to download the collected data. At the same time, one of these goals is prioritized: the lowest energy consumption, the highest reliability of information delivery, or the balance between the previous two. Consequently, the system performance is evaluated from each evolved stage and the overall system. The results show that Redundancy and Coded techniques increase the offloading rate, while Brief and Balanced techniques increase the system's energy efficiency. This is because the Brief and Balanced techniques avoid transmitting redundant information, reducing the slot time. The Coded technique presents a better tradeoff between energy efficiency and reliability than the Brief, Balanced, and Redundancy techniques. Finally, the results show the positive impact of ISC on satellite networks that collect information from ground IoT devices to download it to an earth station.