This is in reference to Lost call.
A drop call comprises of 2 things 1.Lost call 2. Call shut down rate
Lost Call Rate : A lost call occurs when a BTS no longer able to detect the reverse link with sufficient quality for the duration of the Traffic channel supervision Timer. In order to avoid this in the Forms the Value of Traffic Channel supervision timer can be increased to 12.
Call Shut down Rate: Call Processing Failures during H/O may create the problem.
In the Critical Trigger Report both the above will be indicated as drop call only.
A Drop call may occur due to the Following
1.Poorly Defined NL
2.High Traffic areas
3.Lack of RF Coverage
4.Poorly Optimized Border Sectors
6.Search Window Parameters
7.SM ( Switch Module) Problem