5G • 5G-Advanced (Rel-18)
SBFD Fractional Frequency Reuse
Cell-Edge Sub-Band Fractional Reuse Coordination
Network planning strategy where adjacent cell sites alternate their DL and UL sub-band positions across the carrier to prevent mutual tower-to-tower interference.
Technical Explanation
To prevent inter-gNB interference without extreme guard bands, operators can alternate subband frequency assignments across neighboring towers: Cell A uses low subband for DL and high subband for UL, while Cell B uses low subband for UL and high subband for DL. This fractional frequency reuse strategy prevents direct main-beam alignment into neighboring receivers.
Key Functions
- Alternates DL/UL sub-band placement between adjacent cell sites across geographic clusters
- Mitigates inter-tower line-of-sight interference without requiring massive physical guard bands
- Increases average SINR by 8 dB across cell-edge user connections
- Enables dense deployment of full-duplex capabilities in commercial mid-band cellular grids
Specifications
3GPP TR 38.858 (Rel-18)
Interfaces
XnO1
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