A Caching Based Robust Routing Algorithm Using DDR for LEO Constellation Networks

The Laser Inter-Satellite Link (LISL) has emerged as a promising method for achieving higher transmission rates, increasing bandwidth, and reducing power consumption in Low Earth Orbit (LEO) constellation networks. Currently, a variety of routing algorithms have been developed for LEO constellation network with LISL. However, most of them assumed that the LISLs are stable, and none of them considered the packet loss caused by the LISL jitters. When the LISL is jittering the packet loss ratio becomes higher, and the LISLs are not stable actually. This paper proposes a caching-based robust routing algorithm for LEO constellation with LISL by using the Double Data Rate SDRAM (DDR). Specifically, the packets transmitted in the most recent time period on each LISL are ring cached in DDR, and the cached packets are rerouted in the interruption event of LISL. We propose a detailed software and hardware caching based routing system design and show its advantages in LISL constellation networks. Various simulations are constructed, and our proposed algorithm outperforms the existing routing algorithm in terms of packet loss ratio.