5G • 5G-Advanced (Rel-18)
SBFD Uplink Coverage Boost
Cell-Edge Uplink Duty Cycle and Budget Expansion
Overcomes the severe uplink coverage penalty of TDD networks by expanding uplink transmission duty cycle from 20% to 100% across the UL sub-band.
Technical Explanation
Because typical TDD networks allocate 70-80% of time slots to downlink, user terminals are constrained to a 20-30% uplink duty cycle, severely limiting uplink coverage at cell edges. SBFD provides 100% time-domain availability on the UL subband, enabling UEs to accumulate energy across continuous slots and boosting cell-edge uplink link budgets by 5 to 7 dB.
Key Functions
- Increases effective uplink transmission duty cycle from 20% to up to 100%
- Improves cell-edge uplink link budget by 5 to 7 dB without raising terminal peak power
- Eliminates severe uplink bottlenecking in high-resolution video surveillance and live streaming
- Expands commercial 5G cell radius in mid-band (3.5 GHz) TDD spectrum
Specifications
3GPP TR 38.858 (Rel-18)
Interfaces
Uu (PUSCH)
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