Compressed Channel Estimation with Position-Based ICI Elimination for High-Mobility SIMO-OFDM Systems

TL;DR

This paper introduces a position-based ICI elimination method for high-mobility SIMO-OFDM systems, improving channel estimation accuracy by exploiting train position and channel sparsity, and designing optimal pilot patterns.

Contribution

It proposes a novel ICI mitigation technique using train position information and a new pilot pattern design to enhance compressed sensing-based channel estimation in high-mobility scenarios.

Findings

ICI can be eliminated with CE-BEM based channel model.

The optimal pilot pattern improves CS channel estimation accuracy.

The scheme is robust to high mobility conditions.

Abstract

Orthogonal frequency-division multiplexing (OFDM) is widely adopted for providing reliable and high data rate communication in high-speed train systems. However, with the increasing train mobility, the resulting large Doppler shift introduces intercarrier interference (ICI) in OFDM systems and greatly degrades the channel estimation accuracy. Therefore, it is necessary and important to investigate reliable channel estimation and ICI mitigation methods in high-mobility environments. In this paper, we consider a typical HST communication system and show that the ICI caused by the large Doppler shift can be mitigated by exploiting the train position information as well as the sparsity of the conventional basis expansion model (BEM) based channel model. Then, we show that for the complex-exponential BEM (CE-BEM) based channel model, the ICI can be completely eliminated to get the ICI-free pilots at each receive antenna. After that, we propose a new pilot pattern design algorithm to reduce the system coherence and hence can improve the compressed sensing (CS) based channel estimation accuracy. The proposed optimal pilot pattern is independent of the number of receive antennas, the Doppler shifts, the train position, or the train speed. Simulation results confirms the performance merits of the proposed scheme in high-mobility environments. In addition, it is also shown that the proposed scheme is robust to the respect of high mobility.