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While UE attachment, should UE context release happen if Initial Context Setup is not received @ eNB?

+1 vote


In LTE, while UE makes an RRC Connection attempt and in the followed by procedures, if S1AP: Initital Context Setup Request is BLOCKED from MME to eNB, then what eNB should do ideally?

Should it do UE context release, if Initial Context Setup Request message is not received at aNB?

posted Jan 7, 2015 by Sourav Mondal

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MME must be expecting Initial context setup response or Initial Context setup failure in this case. If not received any of these then ideally it (MME) should re-initiate the request.

I hope I understood the question correctly.
Thanks for your update.
But, we are intentionally blocking ICSR at MME. What action should UE and eNB take during that time? As there are some timers running on both eNB and UE, what if they expire during this period?

In particular, if we are able to block ICS Request message, should eNB do RRC release?
What is the name of the timer if it is inactivity then it should be context setup release.

If it is some other timer then ideally it should re-initiate the process before marking it release.

2 Answers

+1 vote

When eNodeB does not receives initial context setup request from MME then eNodeB sends rrcconnection release to UE.

answer Jan 7, 2015 by Veer Pal Singh Yadav
Is it vendor's proprietary implementation or 3GPP standard says. If it is defined in 3GPP then please share the reference. Thanks in advance.
This timer is not defined in 3GPP standard. It is vendor's specific.
0 votes

As per 24.301 specification, UE starts timer T3410 once it triggers Attach request and wait for Attach Accept or Reject. On timer expiry T3410, UE-NAS layer starts timer T3402 or T3411. For more details, please go through specification.

answer Jan 7, 2015 by Vimal Kumar Mishra
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0 votes


this is the scenario:

  1. UE is attached to an eNodeB
  2. UE performs (or not performs, it's the same) UL/DL data traffic
  3. After a few seconds: on UE I see on display that icon signal it is emptying. There is no signal anymore. UE doesn't send any particular message.
  4. Network side, I see that eNodeB sends to MME a "UE context release request" with cause "radio connection with UE lost" or "user inactivity" (also when UE is downloading/uploading!!!).
  5. As result, UE is no more able to attaches to eNodeB again: it is necessary the airplane mode to initiate the attach procedure again.

I think that UE loses the signal after eNodeB sends the "UE context release request"...

Whose fault is it?
Is device faulty? Because the problem is not present for other devices...
Or is eNodeB faulty? Because the problem is not present under another eNodeB.

I don't understand. Sorry and thank you if you'll answer.

+2 votes

Please can anyone explain me,
In which Scenario, eNB send Idlemodemobilitycontrolinfo IE with release cause "other" inside RRC CONNECTION RELEASE message to UE???

+1 vote

Does LTE UE needs to know about the AS release supported by E-NodeB so that it will avoid sending of the IEs which are not supported by ENB