Hello friend!
TCHBUSYTHRES is a parameter. The name of this parameter is TCH Traffic Busy Threshold.
Parameter Description
When the current channel usage reaches or exceeds the value of this parameter, TCHHs are preferentially allocated. Otherwise, the TCHF is preferentially allocated.
NOTE
If this parameter is set to a large value, cell congestion may occur in peak hours. If this parameter is set to a small value, TCHHs are allocated when the cell load is light, affecting the voice quality.
Hope it helps you!