Deciding factor for sCellIndex definition

5G NR
,
1

Hi Folks,

Recently I observed in a few log files, the sCellIndex for ENDC 5G-NR SCG is configured with :

  • Case1: sCellIndex 2,3,4
  • Case 2: sCellIndex 8,9,10
  • Case 3: sCellIndex 9,10,11

For SCC1, SCC2, and SCC3 respectively in a 4CA configured network.

Here the spCellConfig uses 1,7 & 8 as servCellIndex respectively.
One sample (case3) is shown below: (9,10,11 case)

    spCellConfig
    servCellIndex 8,

        sCellToAddModList 
            *sCellIndex 9,*
            sCellConfigCommon *
    ‘’’’’’’’’’’’’’’’’’’’
    ‘’’’’’’’’’’’’’’’’’’’’’
    sCellIndex 10,
    sCellConfigCommon
    ‘’’’’’’’’’’’’’’’’’’’
    ‘’’’’’’’’’’’’’’’’’’’’’
    sCellIndex 11,
    sCellConfigCommon

Can anyone help me to understand what is the deciding factor for this type of index definition?
If life is normal we expect scellindex 2,3, and 4 and PScell in servCellIndex as 1.
Is this defined by vendors like Nokia, Ericsson or Huawei?
If so, is there a technical reason of choosing the above 3 cases?

Any help on this topic is highly appreciated.

I can make a wild guess: If Scell 1 to 6 is used by LTE for 7 CA, there is possibility for 5G SCG PSCell will be 7 and SCG SCC1 can take values from 8,910…and so on for Eg :may be a multiradio e/gNB
But still I see for case 3, PSCell taking value 8, and SCG scc1 from 9,10,11…which makes me confused to even guess the above point.