there are drop calls in all the sites ,with lost TCH radio link,lost sdcch radio link
when checked in OMC-R report
please let me know what i need to do, do i have to perfofm Drive test and check log files.
national call in the network are free, if the duration of calls exceed 20 minutes ,the MSC drops the call.
can i relate this reason for lost TCH and SDCCH radio link.