5G • 5G-Advanced (Rel-18)
gNB-to-gNB CLI Coordination
Inter-Base-Station Cross-Link Interference Coordination over Xn
Xn interface signaling protocol where neighboring gNodeBs exchange SBFD sub-band allocations and beam directions to prevent mutual receiver blinding.
Technical Explanation
Because base stations feature high mast heights and massive transmit power, Line-of-Sight interference between neighboring towers in SBFD can overpower weak mobile signals by 60 dB. Rel-18 establishes inter-gNB coordination over Xn, sharing time-frequency sub-band allocations and planned high-power downlink beam directions so adjacent towers can coordinate antenna beam nulls.
Key Functions
- Exchanges active SBFD subband allocation maps across the Xn interface
- Coordinates inter-site spatial beam nulls to shield neighboring receiver towers
- Establishes synchronized guard periods for high-power inter-cell line-of-sight paths
- Maintains high network throughput across dense urban macrocell clusters
Specifications
3GPP TR 38.858, TS 38.423 (Rel-18)
Interfaces
Xn-CXn-U
Want to memorize 5G concepts like this one?
Study it with SuperMemo SM-2 spaced repetition flashcards.