Information in DCI that indicates if the scheduled PDSCH is Old or New

Hi Experts.

When UE doesn’t decode PDSCH correctly it sends a NACK.

Then gNB sends DCI again for scheduling a retransmit.

Does anyone know if there is an information in DCI that indicates if the PDSCH scheduled is Old or New?

Admin note: this post was updated with image below.

NDI bit toggled if new tx.

1 Like

Is that for both UL and DL?

Yes, for both.

1 Like

Yes. RV - Redundancy Version

I think this one is for PUSCH.

That’s my understanding as well…

How exactly?

This is a field in DCI.

I think it’s sent like 0 2 1 3

0 for tx

Rest for retx

So through this field UE can know if PDSCH is new or no?

Yup, correct.

1 Like

Makes sense…
Because 4 RV values and up to 8 TX possible.

Infact 16 in 5G.


So it’s both NDI and RV?

Yes, correct.

1 Like

What does 16 indicate here?

I think he’s mentioning HARQ process.