5G • RAN
Codebook Type II
Type II High-Resolution CSI Codebook
High-resolution codebook combining multiple DFT beams with linear phase and amplitude weights for MU-MIMO.
Technical Explanation
Type II Codebooks allow the UE to select a subset of orthogonal beams (e.g. L=2, 3, or 4 beams) and report complex amplitude and phase combining coefficients for each beam across frequency subbands. This high-resolution feedback allows the gNodeB to form ultra-narrow nulls, eliminating inter-user interference in Multi-User MIMO (MU-MIMO).
Key Functions
- Provides high-resolution linear combination of orthogonal spatial beams
- Enables precise null-steering for high-capacity Multi-User MIMO (MU-MIMO)
- Transmits complex amplitude and phase weights across frequency subbands
Specifications
3GPP TS 38.214
Interfaces
Uu
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