5G • 5G-Advanced (Rel-18)
Sidelink RTT Ranging
Direct Two-Way Time-of-Flight Distance Measurement
Direct peer-to-peer Round Trip Time protocol that measures physical distance between moving vehicles and pedestrians with sub-decimeter precision.
Technical Explanation
Passive signal strength (RSSI) is too erratic for collision avoidance. Rel-18 Sidelink RTT Ranging implements precise two-way Time-of-Flight (ToF) message exchanges directly over the PC5 interface: by measuring exact round-trip propagation nanoseconds, two vehicles calculate their true physical distance with 10 cm accuracy.
Key Functions
- Measures direct physical distance between moving devices using Time-of-Flight ranging
- Achieves sub-10 centimeter distance accuracy without requiring base station triangulation
- Enables automated valet parking and tight highway truck platooning with minimal gap spacing
- Operates robustly in rain, fog, and darkness where optical camera sensors degrade
Specifications
3GPP TR 38.857, TS 38.215 (Rel-18)
Interfaces
PC5 (Ranging Protocol)
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