X2 between 2 operators can be possible border cell on mutual handshake.
So thinking same.
Anyone tried?
Only condition for re-establishment is cell to be eligible.
But I guess OEMs of UE have put some conditions like this: try firts on old EARFCN, then on same PLMN, then on different PLMN.
UEs donāt scan other PLMN in connected state.
Only mechanism for UE to move to different PLMN is idle mode and then being rejected by the current PLMN or something.
I donāt know if there is mechanism to force UE onto different PLMNā¦
But re-establishment is happening in idle mode.
If T311 expires and UE does not find an eligible cell only then UE will go to idle.
But eligible cell means anything.
As long as Qrxlevmin is ok it will camp on it and try to re-establish the call.
On different PLMN likely it will get rejection.
Ok thanks. So different PLMN scenario practically not possible.
There would be TAU, RRC Reest not possible on diff PLMN ideally.
Iām getting confused. Re-establishment is connected mode, hence the term to re-istablish RRC
Eligibility is one thing but no vendor or network has mechanism to allow UE to send RRC request to different PLMN just because other cell has better coverage.
Even in the scenarios of MOCN networks where UE us provisioned with multiple PLMN it doesnāt send RRC Re-establish next priority PLMN.
Re-establishment is happening after radiolink failure.
UE basically needs to find an eligibel cell and to send rrc re-establishment requests on that cell.
But is doing this based on eligibility fo cell to camp on it.
There are citie sin this world where more than 10 PLMNs are available from 3-4 different countries.
It is not uncommon for UE to stay 4-5 minutes without service in such a location.
Till it scans all PLMNs attempt registration on each and on each RAT.
Hi. Is it possible to RRC re-establish to even another cell?
eNB will not have rnti details, so how does it works?
It will retrieve UE context.
So it is possible re-establishment on different cell and most of the time is successful if the source cell and target cell ar eneighbours.
Re-establishment in idle mode Iām seeing UE reading MIB, SIB 1 of target cell before sending re-establishment request.
It is not idle, UE still has a valid context.
But it just needs to camp on a new cell.
And this is done based on Rxlev, nothing else
If the cell is eligible UE will camp on it and re-establish the call there.
Ok, thanks.
Then why UE reading MIB, SIB1 after RLF of target cell?
Then sending re-establishment request on target cell?
I think youāre referring re-establishment on source cell case?
RLF is (always) happening on source cell.
So after RLF UE has to find a new cell so it is searching for one.
And it is searching based on RXlev to camp on one.
It is cell selection, not reselection.
Yes, always.
UE have option to do re-establishment on source cell as well.
If RLF based HO trigger feature not there I mean rlf on X2.
We are not taking about handovers too early or too late.
This is something else, is call re-establishment.
RLF based HO trigger feature used only for call re-establishment on target cell using X2.
During all this T311 there is no UE TX power!
UE is not transmitting anything after N310, T310, N311 and during T311 running.
All that UE does is searching for a new cell.
Eligible cell, to attempt the reestablishment there.
yes agree.
If there is X2 between source and target then UE context transfer using RLF based HO trigger.