DL SNR to CQI Mapping for UE with Different Chipset

RAN
1

Dear Experts,

DL SNR to CQI conversion is standard for the UE’s having Different Chipset Like Apple/QUALCOMM/Mediatek/Samsung Etc.or Different Chip Makers have Different Algorithm to Convert SNR to CQI. I read somewhere that Every Chipmaker have different SNR to CQI conversion. Some Reports Stringent CQI ( Lesser than what Actual CQI) values and some reports bit Relaxed CQI Value( Higher than Actual Value) in that Case MCS allocation will be different.

2

All vendors are bound to follow Standard rule under the guidance of 3GPP. So DL SNR to CQI mapping for UE has to be standard. It may vary depends on sensitivity level of UE ( Handset).

3

My understanding is that atleast till 4G, there is no mention of SNR at all in 3gpp(please point to such reqs if any). 3GPP only deals with CQI and it’s UE vendor responsibility to map SNR to CQI. Not sure about 5g though.

4

Yes Thats true as 3GPP Doesn’t explicitly mentioned about SNR…it only Mentioned RSRP/RSRQ/CQI in Physical Layer Measurement Procedure. It’s Upto the UE vendor How They Map SNR to CQI. My question is specifically Related to UE Vendors… does all UE Vendor Reports same CQI under Same RF Condition or it Differs Vendor to Vendor…