6A.2.2 CQI definition when the UE is configured in MIMO mode

25.2143GPPPhysical layer procedures (FDD)Release 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

This definition of CQI applies only when the UE is configured in MIMO mode.

Based on an unrestricted observation interval, the UE shall report the highest tabulated CQI value(s) for which a single HS-DSCH sub-frame formatted with the set of transport block size(s), number of HS-PDSCH codes and set of modulation(s) corresponding to the reported CQI value(s) could be received with individual transport block error probabilities not exceeding 0.1 in a 3-slot reference period ending 1 slot before the start of the first slot in which the reported CQI value(s) is/are transmitted if the preferred primary precoding vector as indicated by the PCI value reported in the same HS-DPCCH sub-frame would be applied at the Node B for the primary transport block and in case two transport blocks are preferred the precoding vector orthogonal to the preferred primary precoding vector would be applied for the secondary transport block. When single-stream restriction is not configured and depending on the UE category as derived by higher layers [5], either Table 7H, 7I, 7Ia or 7Ib shall be used for dual transport block type A CQI reports, and either Table 7C, 7D, 7F or 7G shall be used for single transport block type A or type B CQI reports.

Type A CQI reports are constructed using a CQI value that is computed according to

where CQI₁ indicates the supported transport format according to Table 7H, 7I, 7Ia or 7Ib for the transport block that could be received with the specified block error probability if it was transmitted with the preferred primary precoding vector and CQI₂ indicates the supported transport format according to Table 7H, 7I, 7Ia or 7Ib for the transport block that could be received with the specified block error probability if it was transmitted with the precoding vector orthogonal to the preferred primary precoding vector. CQI_S indicates the supported transport format according to Table 7C, 7D, 7F or 7G for the transport block that could be received with the specified block error probability if it was transmitted with the preferred primary precoding vector.

When single-stream restriction is not configured type B CQI reports are constructed using the CQI value of the supported transport format according to Table 7C, 7D, 7F or 7G for the transport block that could be received with the specified block error probability if it was transmitted with the preferred primary precoding vector.

When single-stream restriction is configured type B CQI reports are constructed using the CQI value of the supported transport format according to Table 7A, 7B, 7C, 7D, 7F or 7G for the transport block that could be received with the specified block error probability if it was transmitted with the preferred primary precoding vector.

For the purpose of CQI reporting, the UE shall assume a total transmit power of HS-PDSCH

in dB,

where the total transmit power is assumed to be evenly distributed among the HS-PDSCH codes corresponding to the reported CQI value, and the measurement power offset is signaled by higher layers. denotes the combined transmit power of the set of CPICH(s) used for MIMO operation of HS-DSCH.

When single-stream restriction is not configured and if a CQI for a single transport block is reported, the parameter that is given by Table 7C, 7D, 7F or 7G depending on the UE category and configuration indicates a reference power adjustment for the Node B transmit power on the indicated HS-PDSCH(s). If a CQI for two transport blocks is reported, the parameter that is given by Table 7H, 7I, 7Ia or 7Ib depending on the UE category and configuration indicates by how much the equivalent AWGN symbol SINR for a specific transport block would be different from the one required to meet the predicted BLER performance.

When single-stream restriction is configured, the parameter that is given by Table 7A, 7B, 7C, 7D, 7F or 7G depending on the UE category and configuration indicates a reference power adjustment for the Node B transmit power on the indicated HS-PDSCH(s).

When deriving the CQI value, the UE assumes that the Node B would be using a uniform power allocation across the number of HS-PDSCH codes corresponding to the CQI value to be reported. In case the UE reports a CQI for two transport blocks, it is assumed by the UE that the Node B uses an equal power per HS-PDSCH code for both of the two transport blocks.

When the Node B schedules the UE with two transport blocks, if the Node B does not transmit with equal power per used HS-PDSCH code or use different power per code than indicated by the measurement power offset , it should not assume that the reported transport block sizes can be received with the specified block error probabilities or that transmission of two transport blocks is preferred by the UE.

Further, for the purpose of CQI reporting, the UE shall assume the number of soft channel bits available in the virtual IR buffer (NIR), and redundancy and constellation version parameter (Xrv, Xrvpb, or Xrvsb) as given by Table 7A, 7B, 7C, 7D, 7F, 7G, 7H, 7I, 7Ia or 7Ib depending on the UE category and on the CQI report type irrespective of the actual number of HARQ processes that are configured.

For the purpose of CQI reporting the UE shall assume that all HS-PDSCH channelisation codes it may receive are under the same scrambling code as the set of CPICH(s) used to determine.