A channel equalizer for use in a receiving system includes an overlap unit, a first estimator, an interpolator, and a second estimator. The overlap unit overlaps a group of normal data packets including a head, a body, and a tail, and a known data region is periodically repeated in the body. The first estimator estimates CIRs of the known data regions according to a first algorithm, and the interpolator estimates CIRs of normal data regions in the body by interpolating the estimated CIRs of the known data regions. The second estimator estimates CIRs of normal data regions in the head and tail according to a second algorithm different from the first algorithm. A calculator calculates equalization coefficients based on the estimated CIRs and a compensator multiplies the overlapped data with the coefficients. A save unit saves the compensated data.