5G • 5G-Advanced (Rel-18)
Inter-Cell NC-JT over Xn
Non-Coherent Joint Transmission Across Autonomous Base Stations
Enables two completely independent gNodeBs connected over standard Xn interfaces to transmit parallel data streams to a single mobile terminal.
Technical Explanation
While earlier multi-TRP releases required radio heads to connect to the identical baseband unit (intra-gNB), Rel-18 standardizes Inter-Cell NC-JT over the inter-base-station Xn interface. Using synchronized scheduling windows and distributed buffer management, two independent base station towers stream data to a mobile terminal simultaneously, doubling user data rates without expensive shared baseband hubs.
Key Functions
- Enables simultaneous multi-stream data transmission from separate autonomous gNodeBs
- Operates over standard inter-base-station Xn interfaces without specialized fronthaul
- Doubles throughput at the junction where coverage zones of neighboring cell towers overlap
- Enhances radio link reliability by preventing single-point base station dropouts
Specifications
3GPP TR 38.859, TS 38.423, TS 38.214 (Rel-18)
Interfaces
Xn-CXn-UUu
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