Feature to bring UE back from 4G to 5G

Mobility
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1

Hello Experts.

While moving from 5G to 4G by EPSFB / Handover, is there any feature at 4G end to bring UE back to 5G RAT?

Like in 3G we have smart LTE layering feature to bring UE back to 4G RAT?

2

Yes,. Fast return to 5G.

3

Ok thanks!

How algorithm works?

Is it by RRC connection release having NR ARFCN?

How much time UE take to move roughly?

4

There are 2 options:

  • After VoLTE call is disconnected, i.e. QCI-1 bearer is release eNB can configure B1 / B2 event to move UE to 5G based on measurement.
  • After VoLTE call is disconnected, upcoming RRC release will redirect UE to NR ARFCN.
5

Hi all,

Did you observe fast return to 5G after EPSFB call, without RRC release in LTE? Checking chipset RRC state we do see that UE dropped RRC connection before reselection to 5G SA. But we don’t see DL RRC release message. Does anybody had the experience with this behaviour? Looks like UE vendor feature.