A receiver for receiving a sequence of OFDM symbols transmitted via a channel. Each OFDM symbol comprises a plurality of data bearing sub-carriers and a plurality of pilot bearing sub-carriers. The receiver includes a channel estimator, and the channel estimator includes a pilot data extractor, a pilot data extrapolator and a pilot data interpolator operable to process the pilot data by interpolating between the extrapolated pilot data in time and frequency. The receiver also comprises a discontinuity detector for detecting a discontinuity in the pilot data processed by the channel estimator, and a controller, which upon detection of a pilot data discontinuity by the discontinuity detector, is operable to provide a control signal to the channel estimator which causes at least one of the pilot data extractor, the pilot data extrapolator and the pilot data interpolator to compensate for the discontinuity in the pilot data.