Correlative Coding Based Channel Estimation for Practical OFDM Systems over Time Varying Channels

OFDM systems encounter performance degradations in mobile environments due to inter-carrier interference (ICI) caused by Doppler spread. We find that previous studies using pilots to track the channel time variations always regard the ICI on pilots as additive white noise, which actually increases the estimation errors. As an enhancement of our previous studies on uneven pilot-assisted time-varying (TV) channel estimation (CE) for practical OFDM systems, to further improve the estimation precision, this paper employs the correlative coding to compress the ICI from data to pilots. Simulation results show that by using such a simple coding method, the ICI coefficient is reduced greatly and the estimation Mean Square Error (MSE) dropped by 3dB. It is proved that the correlative code based TV CE method is feasible for practical mobile OFDM systems with good performance and bandwidth efficiency.