Method and apparatus for estimating doppler spread

A method, comprising:

• sampling a signal with a known sequence pn received over a Rayleigh fading channel, and
• calculating a Doppler spread associated with the Rayleigh fading channel by autocorrelating a sequence of complex channel estimates obtained from the known sequence in a first sampling interval and the known sequence in a second sampling interval.

Apparatus for use in a receiver, comprising:

• a detector configured to detect a signal with a known sequence received over a Rayleigh fading channel associated with a communication with a transmitter, and
• a Doppler spread estimator configured to estimate a Doppler spread associated with the Rayleigh fading channel including an autocorrelator configured to calculate an autocorrrelation function of a sequence of complex channel estimates determined using the known sequence.

Apparatus, comprising:

• means for sampling a signal with a known sequence pn received over a Rayleigh fading channel, and
• means for calculating a Doppler spread associated with the Rayleigh fading channel using an autocorrelation function of the Rayleigh fading channel determined using the known sequence samples in the received signal.

The apparatus in claim 30, further comprising:

• means for determining a zero crossing for the autocorrelation function Ĉl.

The in claim 31, wherein the zero crossing is a first zero crossing determined for the autocorrelation function Ĉl and is determined by interpolation.