5G • 5G-Advanced (Rel-18)
Earth-Fixed Spot Beams
Satellite Phased Array Ground-Locked Beam Steering
Satellite electronically steers its beams backward as it orbits, keeping the coverage beam locked to a fixed geographic area on Earth for several minutes.
Technical Explanation
In Earth-Moving beam systems, beams sweep across the ground at 7.5 km/s, forcing users to execute handovers every 5 seconds. Rel-18 Earth-Fixed Spot Beams leverage advanced electronically steered phased arrays: the satellite locks its antenna beam onto a specific city or county, counter-steering against its orbital motion to provide stable multi-minute coverage.
Key Functions
- Electronically counter-steers satellite beams to lock onto fixed geographic coordinates
- Prevents rapid handover storms by keeping users on the same logical cell for minutes
- Maintains stable cell identification and broadcast system information across regions
- Minimizes control plane signaling load on user terminals and satellite payloads
Specifications
3GPP TR 38.821 (Rel-18)
Interfaces
Satellite Phased Array
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