Iterative ICI cancellation and signal detection of OFDM system on fast time-varying channel with nonintegral-delay

In this paper, we present an improved iterative interchannel interference (ICI) cancellation and signal detection technique for orthogonal frequency division multiplexing (OFDM) system on fast time-varying fading channel with nonintegral-delay. As a consequence of the time-varying channel, the orthogonality of subcarriers is destroyed, resulting in interchannel interference (ICI), which increases an irreducible error floor in proportion to the normalized Doppler frequency. In addition, due to the channel delays ranging in the guard period arbitrarily, an error floor of performance occurs by use of conventional integral-delay techniques. The important feature of the proposed technique is the ability to exploit the detective data for ICI mitigation and the estimation and update of channel parameters by use of estimating signal parameter via rotational invariance techniques (ESPRIT). This enables us to achieve performance superior to the conventional structures without ICI mitigation or with integral-delays.