A method of ascertaining a signal power of an Orthogonal Frequency Division Multiplexing (OFDM) signal, the method comprising: ascertaining a plurality of channel estimates from the OFDM signal, wherein ascertaining the plurality of channel estimates from the OFDM signal comprises: ascertaining one or more channel estimates from a group of one or more of a number of sub-carriers of the OFDM signal; and ascertaining one or more of the channel estimates from a different group of one or more ones of the sub-carriers of the OFDM signal, and characterized in estimating one or more compensating phase shift values for aligning the plurality of channel estimates with respect to phase; generating a plurality of phase corrected channel estimates by using the one or more compensating phase shift values to align the plurality of channel estimates with respect to phase; coherently combining the phase corrected channel estimates, thereby ascertaining the signal power of the OFDM signal; that estimating the one or more compensating phase shift values for aligning the plurality of reference symbols with respect to phase comprises: ascertaining a power delay profile (300, 350) of the channel through which the OFDM signal was transmitted; applying a Fast Fourier Transform to the power delay profile (300, 350) to obtain an estimate of the channel through which the OFDM signal was transmitted; and using the estimate of the channel to obtain the one or more compensating phase shift values. ascertaining a plurality of channel estimates from the OFDM signal, wherein ascertaining the plurality of channel estimates from the OFDM signal comprises: ascertaining one or more channel estimates from a group of one or more of a number of sub-carriers of the OFDM signal; and ascertaining one or more of the channel estimates from a different group of one or more ones of the sub-carriers of the OFDM signal, and ascertaining one or more channel estimates from a group of one or more of a number of sub-carriers of the OFDM signal; and ascertaining one or more of the channel estimates from a different group of one or more ones of the sub-carriers of the OFDM signal, and characterized in estimating one or more compensating phase shift values for aligning the plurality of channel estimates with respect to phase; generating a plurality of phase corrected channel estimates by using the one or more compensating phase shift values to align the plurality of channel estimates with respect to phase; coherently combining the phase corrected channel estimates, thereby ascertaining the signal power of the OFDM signal; that estimating the one or more compensating phase shift values for aligning the plurality of reference symbols with respect to phase comprises: ascertaining a power delay profile (300, 350) of the channel through which the OFDM signal was transmitted; applying a Fast Fourier Transform to the power delay profile (300, 350) to obtain an estimate of the channel through which the OFDM signal was transmitted; and using the estimate of the channel to obtain the one or more compensating phase shift values. ascertaining a power delay profile (300, 350) of the channel through which the OFDM signal was transmitted; applying a Fast Fourier Transform to the power delay profile (300, 350) to obtain an estimate of the channel through which the OFDM signal was transmitted; and using the estimate of the channel to obtain the one or more compensating phase shift values.