Techniques to filter pilot symbols for a pilot in an "adaptive" manner to
provide an improved estimate of the response of a communication channel.
A received signal may experience different channel conditions at
different times, and different multipaths may also experience different
channel conditions even when received close in time. A pilot filter with
an adaptive response is used to provide an improved estimate of the
channel response. Various adaptive pilot filtering schemes may be used.
In a first scheme, the channel conditions are estimated based on the
quality of the received pilot. In a second scheme, the channel conditions
are estimated based on the quality of the pilot estimates (i.e., the
filtered pilot symbols). For each scheme, a particular filter response is
selected based on the estimated quality of either the received pilot or
the pilot estimates.