Data volume analysis of a 100+ Gb/s LEO-to-ground optical link with ARQ

Space-based optical links can, in principle, support high data rates by using power efficient communication schemes and unconstrained spectrum. In particular, direct links from low-Earth orbit (LEO) to ground have the potential to support very high rates due to the short link distances involved. In this work, we consider an architecture for LEO-to-ground links that operate at peak rates of 100+Gb=s. Such rates are routinely achieved over fiber channels using power-efficient, fiber-coupled transceivers; however, free-space systems that use these devices may need additional error control to ensure reliable communication over an atmospheric channel. We analyze the data volume, or throughput, that can be delivered by a LEO-to-ground system using fiber-coupled transceivers in conjunction with automatic repeat request (ARQ) protocols. We show that many terabytes per day can be delivered error-free from LEO to a single ground terminal for a variety of orbit and ground terminal geometries.