Position-based ICI elimination with compressed channel estimation for SIMO-OFDM high speed train systems

In this paper, we consider a typical high speed train (HST) communication system with single-input multiple-output (SIMO) orthogonal frequency-division multiplexing (OFDM). We show that the inter-carrier interference (ICI) caused by large Doppler shifts can be mitigated by exploiting the train position information as well as the sparsity of the basis expansion model (BEM) based channel model. For the complex-exponential BEM (CE-BEM) based channel model, we show that the ICI can be completely eliminated to get the ICI-free pilots at each receive antenna. In addition, we design the pilot pattern to reduce the system coherence so as to improve the compressed sensing (CS) based channel estimation accuracy. In specific, the optimal pilot pattern is independent of the number of receive antennas, the Doppler shifts, the train position, or the train speed. Simulation results confirm the effectiveness of the proposed scheme in high-mobility environments. The results also show that the proposed scheme is robust to the train moving speed.