  We present a channel spectral estimator for OFDM signals containing pilot
carriers, assuming a known delay spread or a bound on this parameter. The
estimator is based on modeling the channel's spectrum as a band-limited
function, instead of as the discrete Fourier transform of a tapped delay line
(TDL). Its main advantage is its immunity to the truncation mismatch in usual
TDL models (Gibbs phenomenon). In order to assess the estimator, we compare it
with the well-known TDL maximum likelihood (ML) estimator in terms of
root-mean-square (RMS) error. The main result is that the proposed estimator
improves on the ML estimator significantly, whenever the average spectral
sampling rate is above the channel's delay spread. The improvement increases
with the spectral oversampling ratio.
