What could be the reason for msg3 fail on cell phy?

Hi 5G/LTE Experts.

I have issue with msg3.

I see msg1, msg2 success. And on msg3 on the cell phy Im getting CRC bad on it.
On UE log I see UE is sending msg3 successfully.

What could be the reason for msg3 fail on cell phy?
Although UE is sending msg3 (I see msg3 is sent on UE log)?

Do you mean it is sent by UE but do not reach eNB?

I see its sent from UE but at eNB its not arrived or its arrived but decode fail…

Is it NB-IoT cell?

It seems an UL Radio issue.

Low power for Msg3 or UL interference.

Its new RU, cell is real cell (vbbu).

How do I increase power for msg3?
Is there any specific parameter to increase msg3 power?
(But I’m getting rar and msg1…)

Apart from this, check UL grant.

May be it’s not proper or enough.

This issue is usually seen on NB-IoT cells having capacity issue as prbs are limited.

Yes thats why power and UL interfrence is less likely.

I’m getting crc bad on msg3, so idk if because msg3 not arrived to the cell or its arrived but crc is bad…

Bad means fail right?

Then its clearly not decoded by eNB…

Yes, bad = fail…

Then it’s highly probable that it’s UL interference.

MSG1 will go in open loop power but rest of the MSGs will follow close loop power so you are not seeing issue with MSG1.

MSG3 is transmitted before power control or link adaptation by using initial MCS allocation, initial power and so on.

That is why I guess you could adjust those settings for more robust reception of MSG3.

This is the 1st msg on PUSCH.

Which vendor?

MSG1, MSG2 no issue…
So to increase power for PUSCH?

Yes in PUSCH the MSG3 is first message, so how do I increase power of MSG3?

Yes can be tried if it’s near cell UE.

UE is near the cell. UE is on cell center.

Then it can be tried.

Got you, I will try. :wink:

What I guess is that RU is preventing MSG3 from arriving to the cell…

Crc failing is usually due to interference.

Play with p0 nominal pusch and see if any improvement.

Although balance must be there otherwise may create problems for adjacent cells (co-channel interference for them).

Vendor is Nokia.