5G • RAN
CSI-IM
CSI Interference Measurement Resource
Resource configured by pairing ZP-CSI-RS allocations to measure raw inter-cell interference and calculate SINR.
Technical Explanation
To calculate accurate CQI, the UE must measure both signal power (from NZP-CSI-RS) and interference power. A CSI-IM resource maps to a 4-RE Zero Power CSI-RS pattern where the serving cell transmits zero energy. Any energy received on these REs represents pure inter-cell interference.
Key Functions
- Measures background inter-cell interference on muted resource elements
- Paired with NZP-CSI-RS channel measurements to compute accurate SINR
- Enables precise modulation and coding rate selection by gNodeB schedulers
Specifications
3GPP TS 38.211, TS 38.214
Interfaces
Uu
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