Hi and sorry to answer late,
to Reduce ur call drop in such condition (cell with important TA) u have to :
– Check 1st ur HW (in such case most important cell are in rural area and their maintenance is so hard , pylone with more than 40 HBA) : Antenna , conbiner, TRXs ect…check alarms
– check ur frequency (in general in this rural area , there is no problem)
if u don’t have any problem from these 2 u have a planification problem u have to add a new site or repeter (u have to locate the source of ur trafic)
Some astuces (not recommended becuase u reduce ur trafic):
Reduce ur RX_LEV_ACCES
Reduce the BS_POWER_MAX
with these two parameters u are sure that u will have a good KPI but with a important reduction of trafic (be carefull :))))))))
Good Luck