Patent ID: 7599453

Claim:
A method of estimating a Doppler spread value of a channel in an Orthogonal Frequency Division Multiplexing (OFDM) system, wherein the channel comprises a plurality of carrier frequencies, the method comprising: a receiver ascertaining a value representing a delay spread of the channel; selecting a set of two or more carrier frequencies from the plurality of carrier frequencies; estimating a Doppler spread value for each of the selected carrier frequencies; and producing an estimate of the Doppler spread value of the channel by combining the estimated Doppler spread values of each of the selected carrier frequencies, wherein the value representing the delay spread of the channel is used in the method to influence the estimate of the Doppler spread value of the channel at least by performing one or both of influencing selection of the set of two or more carrier frequencies from the plurality of carrier frequencies and influencing the estimation of the Doppler spread value for each of the selected carrier frequencies, wherein influencing selection of the set of two or more carrier frequencies from the plurality of carrier frequencies comprises: selecting a variable number, N, of carrier frequencies from the plurality of carrier frequencies, wherein N is a function of the value representing the delay spread of the channel, and wherein influencing estimation of the Doppler spread value for each of the selected carrier frequencies comprises: measuring the selected carrier frequencies for a duration of time, T meas , wherein the duration of time, T meas , is a function of the value representing the delay spread of the channel.