List of all possible 5G NR Handover Scenarios

Hi NR Experts.

As HO most important part so trying to list all possible HO scenarios.

Please let me know if I miss any scenario, or any scenario wrong.

For NSA HO:

  1. HO from menb cell 1 to cell 2 without sgnb cell change
  2. HO from menb cell 1 to cell 2 with sgnb cell change from cell 1 to cell 2
  3. HO from sgnb cell 1 to cell 2 with no change in menb cell
  4. Intra gnb ie between cell 1 to cell 2 of same DU ,CU
  5. Inter gnb ie between cell 1 to cell 2 between different DU ,CU
  6. Intra LTE ie between cell 1 to cell 2 of same enb considering no HO at sgnb
  7. Inter LTE ie between cell1 to cell2 of different enb considering no HO at sgnb
  8. intra LTE ie between cell 1 to cell 2 of same enb considering HO at sgnb from cell1 to cell2
  9. Inter LTE ie between cell1 to cell 2 of different enb considering HO at sgnb from cell 1 to cell 2
  10. intra freq sgnb intra gnb no charge in menb cell
  11. inter Freq sgnb intra gnb no change in menb cell
  12. intra freq Sgnb inter gnb no change in menb cell
  13. inter Freq Sgnb inter gnb no change in menb cell
  14. HO from LTE to ENDC with NR cell release during HO
  15. HO from ENDC to LTE with NR cell release during HO

SA HO

  1. NSA to SA HO
  2. SA to NSA HO
  3. SA HO from cell 1 to cell 2 ie intra gnb HO
  4. SA HO from cell 1 to cell 2 ie inter gnb HO

Please Append or delete any scenario needed or not possible in above list.

@ankgitm: Looks it cover all scenario. :wink: I’ll add if i remember another.

Make sure there is inter-freq as well in that list.
I would also add inter/intra du/cu if it is the case.

Great @marcengo, please help to append point in list. Reply here, and i will consolidate it. Thanks.

For SA to NSA and NSA to SA handover anyone if tested can tell is it like SA cell to NR cell or from SA cell to LTE cell.
As NSA is ENDC so not sure where ue will land up… but it’s required n26 interface for sure.
Concern is that in meas object at SA side we need to define LTE or NR cell Freq mapped with events A3 or A5.
Can it’s like SA to NSA cell HO i.e. intra freq with no change in menb cell.
Or SA to NSA cell inter Freq HO with no change in menb cell.
Other possibility like SA to LTE cell HO i.e. inter Freq with no change in sgnb cell.
Or SA to LTE cell HO i.e. inter Freq with change in sgnb cell.

@ NR experts working hand please comment and share your experience

There is no SA to NSA handover.
It is SA to LTE cell HO (IRAT) and then NR addition (NSA).

MO will be LTE frequency.

Thanks @sadanandk2 for clearing it :+1:
Got it so it’s SA to LTE standalone HO.
And vice versa.

For interworking between NR (SA) and LTE, SIB24 and N26 interfaces both are required.

Sib24 for reselection in Idle mode.
N26 for Connected mode.

Yes, from LTE → NR.

Yes.

For SA to LTE cell reselection which SIB used? Is it SIB5?

Please look for NSA scenario listed. Any correction needed?

Yes NR-> LTE SIB5