OTDR , Optical Time Domain Reectometer” (BSS). Base Station Subsystem, the section of a cellular telephone network responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. A BSS is composed of two parts: the BTS and the BSC. 48) ( BSC). Base Station Controller, an equipment responsible for radio resource allocation to mobile station, frequency administration and handover between BTSs controlled by the BSC.