5G • 5G-Advanced (Rel-18)
SBFD ACLR Compliance
Adjacent Channel Leakage Ratio Control in Sub-Band Full Duplex
Advanced digital pre-distortion (DPD) and filtering techniques ensuring high-power DL sub-bands meet strict ACLR limits without bleeding into adjacent UL sub-bands.
Technical Explanation
Because transmit and receive sub-bands are separated by only a narrow guard interval within the same channel, out-of-band spectral regrowth from power amplifiers can easily swamp adjacent uplink sub-bands. Rel-18 requires enhanced Digital Pre-Distortion (DPD) algorithms that linearize the transmitter output specifically to suppress spectral splatter inside the internal guard interval.
Key Functions
- Linearizes power amplifier output to suppress spectral regrowth near internal guard bands
- Maintains 3GPP ACLR compliance (>45 dBc) within narrow frequency separations
- Prevents transmission leakage from elevating the receiver noise floor on uplink sub-bands
- Optimizes power amplifier energy efficiency while maintaining strict spectral mask limits
Specifications
3GPP TR 38.858, TS 38.104 (Rel-18)
Interfaces
gNodeB Digital Front-End
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