DCR (Drop Call Rate)?

The dropped-call rate (DCR) is the fraction of the phone calls which were cut off before the talking parties had completed their conversational tone and before one of them had hung up because of some reasons. This division is normally estimated as a level of all calls. In versatile communication frameworks utilizing radio channels the dropped-call rate is higher and may range for commercial networks between 0.1% and a few percent. The fundamental purposes behind dropped calls in mobile networks are lack of radio coverage, radio interference between different subscribers.