When 4G device report CQI to eNB, is this CQI derived from RS-SINR or PDSCH SINR perceived by UE?

4G LTE
41

You can calculate same for some more realistic value like 12dB, 15dB.

42

I think different vendor calculate it differently, but PDSCH SINR is estimated in all case.

43

So, to summarize what @AbdurRehman87 has said:

  • UE first calculate RS-SINR;
  • Then convert it to PDSCH-SINR by using Pa;
  • And then derive CQI from UE specific mapping table.
44

Yes. So do you agree with above flow?

45

Total power per port was 60 watt…

Previous settings: (Pa,Pb,RS Per)= (0,0,23)

After BW Change: (Pa,Pb,RS Per)= (-3,1,23)

46

Yes gain to interference ratio.
It is used to translate sinr, rs > sinr, pdsch.

47

I agree with the idea.

48

@rameshp235, can you please tell which handset support reporting RS-SINR?
I checked samsung S9 and S10, and they don’t show this capability.

49

Using Motorola LEX 10i.

50

I think there is no relation between RS SINR and PDSCH SINR.

51

Does we need to enable any special IE to report RS SINR?

52

We can easily find it in NEMO and other DT analyzers.

53

Yes. eNB should configure UE to report RS-SINR.

@Jaeku_Ryu explains PDSCH SINR like this in ShareTechNote:

image

54

This doesn’t work in a live network with interferemce from other cells.

55

I am not sure about reliability of this formula.
But why do you think it wont work?
Intereference from other cells is already considered here from RSRQ

56

Because you can have a site with 3 sectors.
This will have zero interference on RS and strong interference on PDSCH in overlaping area.
So RS and PDSCH won’t have same SINR.
In live network it is even more complicated than this…

57

It is not even expected to have RS-SINR and PDSCH SINR to be same.
It can always be different.

58

In formula there is power for RS and power for PDSCH as representing the SINR for PDSCH.
PDSCH SINR at UE side is not influenced only by RS but also by PDSCH of other cells.
So that formula does not work in live network.

59

That’s what I am saying, this already taken care by RSRQ.
Which consider intereference from PDSCH by neighbor cells.

60

The relation between SINR and RSRQ is tricky to handle.
The curves are difficult to interpret.
Minor change in one things lead to a big change in other.
Slight change in RSRQ leads to big change in SINR.