How to keep track of reconnected UEs

[HaoxinSEU]

Hi community,

We would like to keep track of UEs in the gNB. From our understanding, many unique variables like rnti, du_ue_index can represent one specific UE.

However, if the UE reconnects, all these variables are re-generated and new, so that we can not link these new values to the old UE. In other words, if we use these values, the reconnection will be considered as a new UE, instead of a previous UE.

So to track one UE even with reconnection, there should be a state that doesn't change during reconnection. We thought of imsi before, but they are not recorded in the gNB.

Does anyone have an idea about which variable/state we can use for this application? Thanks for your help!

[pgawlowicz]

Hi,
If the UE reconnects quickly, it sends C-RNTI in the RRC Reestablishment Request to recover the old UE context at gNB.