Method for synchronization of base stations which are coupled to different switching system parts in a mobile radio network

A system for synchronization of base stations in a mobile radio network, comprising:

• a first switching system part, to transmit a first synchronization signal, causing a first base station, coupled to the first switching system part, to transmit radio frames which are aligned in time with the first synchronization signal;
• and
• a second switching system part to transmit a second synchronization signal, causing a second base station, coupled to the second switching system, to align its radio frame clock with the second synchronization signal, wherein
• the second base station receives the transmitted radio frames and determines a time error with respect to the radio frame clock, and transmits the time error to the second switching system part, and
• the second switching system part transmits a third synchronization signal to the second base station, with a transmission time selected as a function of the transmitted time error such that the radio frame clock of the second base station is synchronized with the radio frames of the first base station by time alignment with the third synchronization signal.