Optical satellite links stability key to reliable high-speed space communication
Analytical Channel Modeling and Stability Aware Optimization of Optical Inter Satellite Links
Information Theory
Summary
Connecting satellites with laser beams in space can provide very fast data links, but even tiny vibrations cause the beams to misalign and disrupt the connection. The authors created a math model that predicts how these tiny errors affect signal quality between two satellites. Their model shows that the weaker link’s stability dominates connection reliability, while overall link speed depends on both ends. This helps satellite engineers design better communication systems by choosing the right beam settings and stability measures.
What this means in practice
- •For satellite communication engineers: Design optical space links with optimized beam parameters and pointing stability for reliable satellite network performance.
- •For aerospace platform designers: Specify stability and tracking system requirements for satellites to reduce link outages and maximize data throughput.
Authors
Hossein Safi, Ziheng Wang, Stijn Mast, Harald Haas, Iman Tavakkolnia
Abstract
Optical inter-satellite links (OISLs) are key enablers for high-capacity space networks and next-generation satellite constellations. However, their extreme directionality makes link reliability highly sensitive to platform-induced pointing jitter, which causes random misalignment between the transmitter and receiver beams. In this paper, we develop a tractable closed-form statistical channel model for point-to-point OISLs subject to independent pointing errors at both terminals. Accurate Gaussian main-lobe approximations are applied to the transmitter far-field pattern and receiver coupling efficiency. This transforms the diffraction-based channel response into closed-form expressions for the channel-gain distribution, outage probability, and ergodic capacity. The analytical results are validated through Monte Carlo simulations and used to study the impact of terminal stability, beam divergence, and link margin on OISL performance. The results show that outage probability is governed by the weaker terminal in terms of pointing stability, while improving only the stronger terminal provides minimal additional benefit. In contrast, the ergodic-capacity penalty depends on the combined stability of both terminals, revealing a fundamental distinction between reliability and throughput metrics. The proposed framework provides practical design guidelines for selecting beam parameters and specifying pointing and tracking requirements under varying levels of platform instability.