In a digital channel of a digital wireless communication system including at
least
one mobile station, at least one base transceiver station in communication with
the mobile station, a transcoder configured to provide a signal conversion between
vocoder frames and pulse code modulation, and a mobile switching center for interconnecting
the digital wireless communication system to a public switched telephone network,
a method and apparatus for determining a fault in the digital channel is disclosed.
The method includes generating a first set of vocoder input parameters from a speech
input signal, and generating a second set of vocoder input parameters from an output
signal substantially equivalent to the speech input signal as it is received at
a mobile station via the digital channel. The method further includes calculating
a metric based on the first and the second set of vocoder input parameters, and
subsequently determining a fault in the digital channel using the metric.
