Abstract— In this paper, we present a new Doppler spread estimation algorithm for broadband wireless orthogonal frequency division multiplexing (OFDM) systems with time-varying and frequency-selective Rayleigh fading. The algorithm is developed by analyzing the statistical properties of the power of received signals in the time domain, thus it excludes the influence of intercarrier interference introduced by channel variation within one OFDM symbol. The operation of the algorithm doesn’t require the knowledge of fading coefficients, transmitted data symbols, or signal-to-noise ratio (SNR). It works well under time-selective and frequency-selective Rayleigh fading channel with SNR as low as 0 dB. Moreover, unlike existing algorithms, the proposed algorithm takes into considerations of the discrete-time channel inter-tap correlation, as the case in practical systems. Simulation results demonstrate that this new algorithm can accurately estimate a wide range of Doppler spread with l...