5G • 5G-Advanced (Rel-18)
NCR TDD Timing Coordination
Propagation Delay Compensation and TDD Switching for Repeaters
Coordinates TDD transmit-receive switching points to prevent repeater transmissions from bleeding across subframe boundaries and causing cross-link interference.
Technical Explanation
Because signals take time to travel from the base station to the repeater, switching between DL and UL must be precisely adjusted. Rel-18 NCR timing coordination establishes timing advance and guard period offsets calculated by the gNodeB, ensuring the repeater never transmits in DL when the macro network has switched to UL reception.
Key Functions
- Calculates precise TDD switching offsets accounting for base station-to-repeater propagation delay
- Prevents repeater transmissions from spilling over into adjacent uplink reception slots
- Eliminates catastrophic cross-link interference with neighboring base station towers
- Maintains slot alignment with standard 3GPP TDD radio frame structures
Specifications
3GPP TR 38.867, TS 38.213 (Rel-18)
Interfaces
Uu (Timing Advance)
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