What could be reason for LTE to 3G reselection failure?

Question

I am seeing failure cause = 7 or 1

Which spec defines reselection failure causes?

Comments

What is the failure message i.e. is it TAU failure?

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failure is in 3G and i can only see failure in event.
it does reselection successful to other 3G cell but this particular cell it does not reselect

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I did not get the complete case, can you describe the message flow and at which stage its failing then can suggest the specs to look for :)

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Case is: UE should perform LTE to 3G reselection (inter-RAT reselection).
Attach UE to LTE and then decrease power of LTE and UE should perform reselection to 3G

Failure is shown in EVENT-  IRAT reselection from EUTRAN start and cause displayed = 7

Thanks

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This is resolved. It was environment issue

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Hi Alkesh ,

Can you please explain here your findings for the actual reason that was causing this failure ?

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Issue was poor RF and UE inactivity timer was very short

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I think both of these causes are two different things means not-related , so you meant both cause were present simultaneously ? Because Ue inactivity in itself may cause failure of reselection due to idle state inactivity timer expiring even before trying for reselection?

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yes they are not related.