Hi, first of all check kpis from u2020 which type of call setup time had increased, you can just search in the Counter using setup time, and u will find setup time for csfb calls,from pch, Amr nb, Amr WB…this is first thing u do so to understand which call type had increased or it’s same issue for all types, Chk and let me know
3G/2G call setup time, as I initial analysis I found A correlation between increase in the number of VOLTE subscriber , which is also a gradual increase from the same time and corelating with this decrease in UMTS MO/MT Seizure traffic(Erl) .
I think due to migration activity the subscribers to VOLTE