Patent ID: 6785351
Filing Date: 2004-08-31
Classification: H04L

Abstract:
In a wireless communication system wherein a fading process for a channel in said communications system is characterized by a known channel fading process, a method for determining a Doppler frequency shift induced in a signal between two stations comprising the steps of:determining a value for an auto-correlation function of said channel fading process based on a signal received from said channel, said auto-correlation function having a Doppler frequency component; and estimating said Doppler frequency shift as a function of said determined auto-correlation function value; wherein said function of said determined auto-correlation function value for estimating said Doppler frequency shift is specified as fm=1Ï€&it;Ruu&af;(t2)-Ruu&af;(t1)(t1+t2)&it;(t1-t2)where fm is the estimated Doppler frequency, Ruu(&tgr;) is an auto-correlation function value for the received signal and t1 and t2 are any two symbol locations for the received signal.