Please help to explain why we have condition to set the 5G-TMSI.
How network make use of it?
Ng-5G-S-TMSI -part 2 used to indicate N/W that UE is non NB-IOT UE .
please find below Reference for this.
1> consider the current cell to be the PCell;
1> set the content of RRCConnectionSetupComplete message as follows:
2> if the RRCConnectionSetup is received in response to an RRCConnectionResumeRequest :
3> if upper layers provide an S-TMSI:
4> set the s-TMSI to the value received from upper layers;
3> else if upper layers provide a 5G-S-TMSI:
4> if the UE is a NB-IoT UE:
5> set the ng-5G-S-TMSI to the value received from upper layers;
5> set the ng-5G-S-TMSI-Bits to ng-5G-S-TMSI with the value received from upper layers;
2> else if upper layers provide a 5G-S-TMSI:
3> except for NB-IoT, set the ng-5G-S-TMSI-Bits to ng-5G-S-TMSI-Part2 to the leftmost 8 bits of 5G-S-TMSI received from upper layers;