A method detects an absence of a transmitted frame in a wireless communications
system that operates with a discontinuous transmission (DTX) protocol between a
transmitter and a receiver. The method includes decoding a received signal over
a frame period to determine a cumulative metric; normalizing the cumulative metric
and comparing the normalized cumulative metric to a threshold for determining whether
the frame was a transmitted frame or a non-transmitted frame. The determined cumulative
metric may be a maximum cumulative metric or a zero state cumulative metric. The
wireless communications system may be a CDMA system, the receiver may be contained
within a mobile station, and the determination of whether the frame was a transmitted
frame or a non-transmitted frame can be employed, as one non-limiting example,
during execution of a power control algorithm.
