5G • 5G-Advanced (Rel-18)
Inter-Satellite Links (ISL)
Optical Laser and mmWave Space Cross-Links
Laser and high-frequency radio cross-links that route data directly between orbiting satellites in vacuum space, bypassing ground gateway stations.
Technical Explanation
When a satellite flies over the Pacific Ocean, no ground gateway station is in sight. Release 18 regenerative payloads utilize Inter-Satellite Links (ISL)—optical lasers delivering up to 100 Gbps—to hop data from satellite to satellite across space until reaching a satellite positioned over a terrestrial ground station, creating an orbital mesh network.
Key Functions
- Routes user data across an orbital mesh network of interconnected satellites
- Employs high-speed optical laser cross-links delivering 10 to 100 Gbps in space vacuum
- Transports cellular packets across oceans without requiring intermediate island ground stations
- Achieves lower packet latency than terrestrial trans-oceanic subsea fiber cables
Specifications
3GPP TR 38.821, TS 38.300 (Rel-18)
Interfaces
ISL (Optical / mmWave)
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