A radio base station is disclosed that monitors faults of radio communication
modems
based on the content of received frames that are received during call connection.
The radio communication modems are mounted in units of prescribed number on signal
converters of card structure and are assigned to correspond to mobile stations
that perform call connections. The radio base station uses fault detection data
to check the content of frames that are received during call connections for each
radio communication modem, and counts the total number of received frames and the
number of frames in which faults are detected. Upon termination of a call connection,
the radio base station determines whether or not a fault has occurred in a radio
communication modem based on the counted ratio of the number of frames in which
faults are detected to the total number of received frames, and if a fault has
occurred, attempts recovery control. If a radio communication modem does not recover,
the radio base station deletes the radio communication modem as a candidate for
next assignment. The radio base station further transmits, to maintenance personnel
through the radio base station controller, a message prompting exchange of a signal
conversion card in which the number of faulty radio communication modems reaches
or exceeds a particular number.
