Co-Optimization of Optical Ground Station and Network Architecture for Secure and High-Capacity Satcom Ground Segments

Traditional radio-frequency (RF) transmission can no longer keep pace with the growing bandwidth demands of satellite communications. As constellations continue to expand, fundamental limits on individual RF carrier capacity and increasing spectrum scarcity are creating a bottleneck for satellite-to-ground (S2G) links. Free-space optical communication (FSOC) offers an alternative, with optical ground stations (OGS) capable of supporting data rates exceeding 1 Tbps.
Powered by telecom transceiver technology, optical inter-satellite links (OISLs) have already been deployed, with some constellations demonstrating bidirectional bandwidth exceeding 100 Gbps. Additionally, FSOC does not require spectral licensing as there is no practical risk of channel interference. While these advantages extend naturally to S2G links, atmospheric transmission introduces challenges. Key impairments include cloud blockage, aerosol scattering, and turbulence induced wavefront distortion. This paper investigates ground-segment architecture design considerations for optimizing OGS network availability and throughput, leveraging results from demonstrated S2G optical links, atmospheric propagation simulations, and global weather data to provide a system-level analysis.
To ensure S2G FSOC availability, careful site selection with geographic diversity is crucial. OGSs are often located near urban areas, with specific atmospheric conditions (aerosols, particulate pollution, local climate, etc.), differentiating FSOC site optimization from that of RF ground stations. Cloud coverage remains the dominant impairment for link establishment and strongly conditions OGS localization, making site diversity across uncorrelated weather regions essential. This diversity can be further supported by OISL mesh relays, enabling a range of industry-oriented application scenarios such as Earth observation data delivery, satcom backhauling, and resilient mesh-based relay architectures. Atmospheric turbulence can be addressed through mitigation techniques implemented in each OGS, among which the telescope aperture size plays a key role. This paper presents a general framework for optimizing OGS network architecture, followed by simulation-based case studies that highlight pathways toward scalable and efficient S2G FSOC networks.