The performance of wireless devices is improved using methods and devices
which comprise novel SPEED and NOISE metrics. The SPEED metric is
generated from a mean value of a differential signal while the NOISE
metric is generated from a variance value of a differential signal. The
generation of both metrics assumes the use of a limited number of symbols
used to generate the mean and variance values. One example of a signal
used to generate the metrics comprises the 14 synchronization symbols
which make up part of an IS-136 standard signal. The SPEED metric was
discovered to comprise a value which is equal to the magnitude of the mean
value of the differential signal while the NOISE metric was discovered to
comprise a value which is approximately equal to twice the variance of
noise in a received baseband signal, while at the same time being
independent of the speed at which an object, such as a wireless device,
moves. In the case where a Least Mean Square ("LMS") method is used to
estimate channel fading in a flat-faded channel, it was discovered that
the logarithm of a ratio of the SPEED metric to the NOISE metric as
plotted against optimum step sizes is a substantially linear relationship.
