Dear Experts,
I have basic question:
When 4G device report CQI to eNB, is this CQI derived from RS-SINR or PDSCH SINR perceived by UE?
1 Like
PDSCH SINR.
Also this CQI is adjusted by eNodeB according to PDSCH BLER so reported CQI is different compared to used CQI.
PDSCH BLER target is 10%; PDCCH BLER target is 1.5%
Yes @RFSpecialist, right.
This CQI adjustment is called PDSCH OLRC in general.
Note: i got the answer RS-SINR from a friend, so i got confused.
RS-SINR… isn’t it RSRQ?
For RS we have only RSRP and RSRQ, there’s no SINR concept for RS.
1 Like
Not actually.
RS-SINR and RSRQ are totally different.
RS-SINR is introduced in Rel-13.
And UE can also report RS-SINR In Rel13 onward.
It’s RS SINR.
UE calculate RS SINR and using this it determines PDSCH SINR by doing adjustment for Pa values.
Interference can be.
RS RS interference.
RS PDSCH interference.
So SINR calculation depend on same.
Do you mean by RS-EPRI and PDSCH-EPRI?
Has anyone seen in 4G drive tests RS-SINR reported?
I don’t.
I just came across Rel13.
And in Samsung system we got provision to configure RS-SINR reporting by UE.
So ideally, UE can now report, of course UE should support it.
What values would you expect from RS-SINR?
Positive or negative ones?
RS SINR = 18.
And Pa=-3, Pb=1.
PDSCH SINR would be 15.
Values -23 to 40.
PDSCH SINR is given by interference on PDSCH from other cells PDSCH.
What this has to do with RS-SINR?
@ankgitm, I thought RS signal locations in LTE are clearly defined in symbol and PRB/subcarrier so no PDSCH is scheduled on that RS grid locations, regadless of antenna 0,1,2 or 3.
Why do you say there will be interference between RS and PDSCH in this case?
The only interference for RS is from another cell RS’s with same mod3 PCI.
Not from PDSCH.
I’m saying this from field observation and my experience.
Let’s say user downloading in one cell getting interference from other cell RS.
I.e. PDSCH RE gets interfered by RS RE.
But it is clearly designed that no PDSCH is designed in the RS locations.
Same no RS is designed in PDSCH locations.
And this is true for any cell.
Didn’t get your point.
Similar type of interference is also present for RS.
Yes let me get more details.
RS interference is fine.
RS PDSCH is question now.
What I remember it is calculated like below:
Step1. At UE :
PSDrs,rx > SINRrs(estimate)
SINRrs > CQI(calculate)
At enb
CQI > SINRrs(estimate)
GINR = SINRrs - PSDrs,tx
SINRpdsch = GINR + PSDpdsch,tx