Channel estimation for mobile OFDM systems

In this paper we investigate pilot-based channel estimation schemes for mobile OFDM systems. Time variance of the mobile channel leads to a loss of subcarrier orthogonality, resulting in intercarrier interference (ICI). Channel estimation schemes based on pilot tones, which are also subject to ICI, will therefore suffer a performance degradation. In this article we analyse linear minimum mean squared error (LMMSE) estimators to reduce the noise due to ICI and propose two channel estimation schemes which perform interpolation of the noise-reduced pilot tones in the time-direction prior to frequency interpolation. Performance evaluations are based on the European digital television system DVB-T. Receiver complexity is examined for the advanced time-interpolation schemes and compared to state of the art receivers for stationary reception