5G • 5G-Advanced (Rel-18)
SBFD Architecture
Sub-Band Full Duplex Network Architecture
Core 5G-Advanced duplexing innovation where a single contiguous TDD carrier is split into non-overlapping simultaneous Downlink and Uplink sub-bands.
Technical Explanation
Traditional TDD networks operate half-duplex: all base stations and users transmit in DL or receive in UL at the same time. Subband Full Duplex (SBFD), studied in 3GPP Rel-18 (TR 38.858), allows the gNodeB to transmit DL on one portion of the carrier while simultaneously receiving UL on another sub-band, overcoming TDD uplink coverage bottlenecks and slashing round-trip latency.
Key Functions
- Enables simultaneous transmission and reception within a single TDD carrier channel
- Eliminates TDD slot latency waiting times for critical industrial uplink traffic
- Boosts uplink cell-edge coverage by providing continuous uplink transmission opportunities
- Maintains full backward compatibility with legacy half-duplex Release 15-17 UEs
Specifications
3GPP TR 38.858, TS 38.300 (Rel-18)
Interfaces
UuXn
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