OTFS-IM channel estimation and data detection algorithm with a superimposed pilot pattern.

Orthogonal time frequency space modulation (OTFS) has been proved to have better performance over orthogonal frequency division multiplexing (OFDM) under high-mobility environments. In this manuscript, we address the challenging problem of channel estimation in high-mobility scenarios for 5G and beyond. To improve the spectral efficiency of the system, we combine superimposed pilots with index modulation paradigm. Indeed, we propose an iterative algorithm for channel estimation and symbol detection with superimposed pilot pattern for OTFS-IM systems. The proposed algorithm iterates between LMMSE-based data detection and data-aided channel estimation. Performance in terms of spectral efficiency and bit error rate are evaluated and compared against state-of-the-art methods.