Joint time-varying channel estimation with dual-ICI cancellation in OFDM systems

Abstract

Channel estimation plays a vital role in coherent detection and demodulation in orthogonal frequency division multiplexing (OFDM) systems. However, the channel timevariation leads to tremendous unknown parameters to estimate and detrimental inter-carrier interference (ICI) for pilot-aided channel estimation, degrading the system performance significantly. This paper proposes a joint estimation of the highly mobile channel with dual-ICI cancellation for OFDM systems in the absence of prior channel information. First, the linear time-varying (LTV) model is employed to get an initial estimation and leaves the rest channel component with much less ICI to the next estimation in generalized complex exponential basis expansion model (GCEBEM). In the second stage, the output of estimation in GCEBEM is fed back to LTV model to mitigate the ICI compact on the pilots for another iteration. Besides the dual-ICI cancellation, the spectral leakage of GCEBEM is also alleviated. Numerical results verify the priority of the proposed joint estimation over the existing estimations.