LTE CQI/PMI/RI Reporting Overview

Reporting on PUSCH
- Aperiodic Reports
-Wideband CQI (multiple-PMI per subband)
-UE Selected Subband CQI (No-PMI, Multiple-PMI)
-Higher Layer Configured Subband CQI (No-PMI, Single-PMI)
-Frequency selective/non-selective scheduling

Reporting on PUCCH
-Periodic Reports
-Wideband CQI (No-PMI, Single-PMI)
-UE Selected Subband CQI (No-PMI, Single-PMI)
-Frequency selective/non-selective scheduling

Aperiodic CQI/PMI/RI reporting is defined by the following characteristics:
- The report is scheduled by the eNB via the PDCCH
- Transmitted together with uplink data on PUSCH
- From the frequency span perspective these reports can be:
- Frequency selective: UE Selected Subband CQI and Higher Layer Configured Subband CQI
- Frequency non-selective: Wideband CQI reports
- When a CQI report is transmitted together with uplink data on PUSCH, it is multiplexed with the transport block by L1 (i.e. the CQI report is not part of the uplink the transport block). Periodic CQI/PMI/RI reporting is defined by the following characteristics:
- Periodic CQI reports are sent on PUCCH
- From the Frequency span perspective these reports can be:
- Frequency selective: UE Selected Subband CQI
- Frequency non-selective: Wideband CQI reports
A UE can be configured to have both periodic and aperiodic reporting at the same time
- In case both periodic and aperiodic reporting occurs in the same subframe, only the aperiodic report is transmitted in that subframe. Observe that both types of reports: Periodic over PUCCH and Aperiodic over PUSCH enable efficient Frequency-Diverse Scheduling (FDS) and Frequency-Selective Scheduling (FSS).