Robust and Low-Complexity Combined Signal Power Estimation for OFDM

摘要

Ascertaining a signal power of an Orthogonal Frequency Division Multiplexing (OFDM) signal involves ascertaining (205) a plurality of channel estimates from the OFDM signal; estimating (203) one or more compensating phase shift values for aligning the plurality of channel estimates with respect to phase; generating (207) 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; and coherently combining (209) the phase corrected channel estimates, thereby ascertaining the signal power of the OFDM signal. Ascertaining (205) 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. Estimating (203) the one or more compensating phase shift values for aligning the plurality of reference symbols with respect to phase comprises: ascertaining which of a plurality of samples of the OFDM signal would be a starting point of a Fast Fourier Transform (FFT) causing a smallest rotation across sub-carriers (307, 357); and estimating the one or more compensating phase shift values as a function of a relative distance between an actual starting point of the FFT and the starting point of the FFT causing the smallest rotation across sub-carriers.