What is the difference between the contention resolution timer and T300?

Then what is the need of T300?
Ultimately the UE will decide whether to send RRR Connection Setup complete message in UL will decide within 64 ms.

Contention resolution works from msg3 till harq ack.
This is the window. But t300 works from msg3 till msg5.
In short contention resolution is the mediator for msg3 harq ack tru harqmsg3max.

Got it. Thanks!

Thank you folks. Good stuff.

I have one more question. :wink:

Suppose network doesn’t respond to MSG1 requests from UE. How long should UE keep retrying MSG1 with increased power level?

Waiting time for RAR is defined by raRespWinSize.
Generally 10 SF.
Alone eNB KPI are not sufficient, UE logs are also required for msg 1 and 2 troubleshooting.

Raresponsewinsize I think can go upto 12sf.

Also need to check if UE is located beyond cellrange.

Number of preambles max decides how much it retries and initial target preamble power is how much power it should increase in retries.

In Nokia it’s limited to 10.

Would you be able to give the spec ref for this?
In the TS 36.321, I see such requirement only for NB-IoT/Scell/Spcell.