Patent ID: 8472538

Claim:
A method for calculating a delay spread estimate in an Orthogonal Frequency Division Multiplexing—OFDM—receiver, comprising: determining a position of a fast Fourier transform—FFT—window in relation to one or more OFDM-symbols of a received OFDM-signal; using the determined position to obtain a first OFDM-symbol from the received OFDM-signal; applying an FFT to the first OFDM-symbol to produce an FFT-output signal; determining a number of zero-crossings of at least one of a real component and an imaginary component of a transfer function of a channel over which the received OFDM-signal has been transmitted; calculating the delay spread estimate based on the determined number of zero-crossings; determining a frequency dependent phase rotation component of the FFT-output signal; and removing, prior to the step of determining the number of zero-crossings, the determined frequency dependent phase rotation component from the FFT-output signal to obtain a compensated FFT-output signal; wherein the transfer function is determined based on the compensated FFT-output signal, and wherein the step of calculating the delay spread estimate comprises: determining a zero-crossing rate based on the determined number of zero-crossings; and multiplying the determined zero-crossing rate by a scale factor to produce the delay spread estimate.