# RS SINR and PDSCH SINR

Hi Experts,
I have some RS SINR and PDSCH SINR queries…

Considering TEMS RS SINR and PDSCH SINR:

1. PDSCH SINR = RS-SINR + 8 db or 14dB? (before row 972 it’s 8 dB, since row 973 it’s 14 dB - image below).
2. Is there an offset calculation from RS-SINR to PDSCH-SINR?
3. Why sometimes it’s 8 dB, sometimes it’s 14 dB?

Because PDSCH interference is different than SSB interference.
PDSCH is related to scheduling.
SSB interference is related to PCI mod4 in NR.
PDSCH interference is about overlaping between cells and about both cells scheduling in same time same PRB same location.
SSB interference is about cells overlaping and same PCI mod4.

It’s LTE.
Do you think UE just measure RS-SINR then plus offset to give result of PDSCH-SINR?

Please remember same Freq will interfer each other below are type of interference in LTE

1. RS- RS interference.
2. RS - PDSCH interference.
3. PDSCH - PDSCH interference.
In your case you can check overlapping between cells as per ISD.

Do you think calculation of RS-sinr and pdsch-sinr, UE has 2 dintinct measurement method or just only 1 method and 1 reference?

It is impossible to calculate pdsch-sinr. You have to measure it.
Same for rs-sinr.

Method are different but internal calculation.

Both are calculated independently. And method is UE dependent.

Why pdsch sinr = rs sinr + 8 (or 14)?

I think it’s interference between rs - pdsch.

Always 8 or 14.

Yes, it need to be investigated.

Allow me to doubt the correctness. If it is interference is not always 8 or 14 dB. It fluctuates in time and so difference should fluctuate in time not be always 8 or 14 dB. And excuse me for asking, if you can calculate why to measure? I think those are measurements not calculations.

Or at least should be measurements not calculations.
I mean you calculate your signal from your cell because you know its values based on RS. But interference you have to measure it, there’s no way to “calculate” it. So here is goes SINR signal interference noise ratio.

1. Are these measurement f LTE or NR?
2. From field or lab?

LTE, Drive Test.

If pci mod 3 of 2 cells are conflict, rs-sinr is affected because RS location in freq domain are same. Is pdsch-sinr also affected?

It depends if both cells are scheduling in same time, same PRBs which is very unlikely for a long duration. Unless both cells are highly loaded.

Yes, pdsch same prb, same time will interference to each other.
But RS just interference to each other if same time/freq or same pci mod3.

To ensure this, there is a feature called DL FSS.
Works efficiently in light load scenario.

My question is in case 2 cell same pci mod 3, pdsch quality is affected or not?

Here’s a nice picture to understand the relation of signal between rs and pdsch: