How do you measure if a cell is overshooting or how do you determine how many km it should cover?

Hi, umts cells can cover very far… 50km. But usually it is limited by propagation loss. From configuration as said it is limited to .5-1km in urban and 5-10km in rural. This depends on the coverage target of the cell

Analyzing Coverage with Propagation Delay - PD and Timing Advance - TA (GSM-WCDMA-LTE)