Method and apparatus for estimating doppler spread

• US 20020172307A1
• Filed: 03/27/2001
• Published: 11/21/2002
• Est. Priority Date: 03/27/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sandberg, David
• Granted Patent: US 6,922,452 B2
• Time in Patent Office: Days
• US Class Current: 375/344
• CPC Class Codes: H04B 7/01 Reducing phase shift

Abstract

The present invention sets forth a method and apparatus for estimating Doppler spread associated with a Rayleigh or fast fading channel established between a radio base station and a mobile radio station. In particular, the Doppler spread is estimated through calculation of the autocorrelation function of a sequence of complex channel estimates determined from a known sequence in the received signal. More specifically, a sequence of complex channel estimates obtained from the known sequence in a first sampling interval is complex conjugated and then correlated with a sequence of complex channel estimates obtained from the known reference in a second sampling interval which have been not been complex conjugated. A zero crossing of the complex autocorrelation function is detected, and the estimated Doppler spread is calculated using this zero crossing and a Bessel function.

Claims