Factor Graph Based Detection Approach for High-Mobility OFDM Systems with Large FFT Modes
In this paper, a novel detector design is proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems over frequency selective and time varying channels. Namely, the authors focus on systems with large OFDM symbol lengths where design and complexity constraints have to be taken into account and many of the existing ICI reduction techniques cannot be applied. They propose a Factor Graph (FG) based approach for Maximum A Posteriori (MAP) symbol detection which exploits the frequency diversity introduced by the ICI in the OFDM symbol. The proposed algorithm provides high diversity orders allowing to outperform the free-ICI performance in high-mobility scenarios with an inherent parallel structure suitable for large OFDM block sizes.