the most important paramethater is MAX PDCH HIGH LOAD !
The parameters that can cause TCH Congestion are:
MAX PDCH HIGH LOAD
The Max PDCH can be set to a high value, that should not generate TCH Congestion. Indeed, all PDCH located within MAX PDCH HIGH LOAD and MAX PDCH can be quickly preempted by TCH.
Are you talking about TCH NA Congestion, or TCH HO Congestion ?
TCH HO Congestion might be increased when MAX PDCH is high, but i don’t think so. I’m not sure.