Various forms of cyclic-prefixed block transmission have been considered for signal transmission over multipath fading channels. Among them the most well-known is orthogonal frequency-division multiplexing, or OFDM. Whatever the form, such systems usually transmit many known pilots to assist channel estimation and data detection. We consider receiver techniques that can help improve the bandwidth efficiency by reducing the needed amount of pilots. In particular, we consider using only a block of pilots as the preamble. Then the receiver tracks the channel variation via jointly iterative channel estimation and data detection. It uses a frequency-domain equalizer to reduce the complexity. Simulations show that the tracking ability of the proposed method is good.