METHOD OF DETECTING TROUBLES IN A RECEIVER FOR A COMMON CONTROL CHANNEL OF A MOBILE RADIO TELEPHONE COMMUNICATION SYSTEM AND A SYSTEM THEREFOR

摘要

A mobile radio telephone system is described. Mobile stations are free to travel to different zones covered by respective base stations. Speech channel transmitter/receivers are used to transmit and receive speech and access channel transmitter/receivers are used to control calls for the mobile stations. The system has a detection circuit which detects from the output of the access channel receiver of a mobile station a calling signal and a test calling signal. A controller connected to the output of the detection circuit transmits the test calling signal to the access channel receiver if the detection output of the detection circuit is not received within a first predetermined time interval. The control generates a trouble signal if the detection output is not received within a second predetermined interval after the transmission of the test calling signal. The second interval is shorter than the first. The invention automatically detects trouble on an access channel without hindering communication by other mobile stations sending out ordinary call signals.