5G • 5G-Advanced (Rel-18)
Cross-Carrier Beam Indication
Shared Beam Indication Across Carrier Aggregation Components
Allows beam direction signaling on one carrier component (e.g. low-band PCell) to configure the spatial filters of a high-band carrier component (e.g. mmWave SCell).
Technical Explanation
Transmitting beam management signaling across multiple wideband component carriers creates substantial control overhead. Rel-18 Cross-Carrier Beam Indication allows a single TCI state signaled on a robust low-frequency primary cell (PCell) to point the beam directions of multiple aggregated mmWave secondary cells (SCells), slashing signaling overhead and accelerating carrier aggregation setup.
Key Functions
- Controls spatial beam directions of multiple carrier components via a single control channel
- Reduces DCI and MAC CE beam management signaling overhead by over 60%
- Leverages robust sub-6 GHz signaling to direct fragile high-frequency mmWave beams
- Accelerates multi-carrier setup in complex multi-band deployments
Specifications
3GPP TS 38.214, TS 38.331 (Rel-18)
Interfaces
Uu (DCI / MAC CE)
Related 5G Concepts
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