Symbol Detection for Intelligent Reflecting Surface-aided Orthogonal Time Frequency Space Systems.

Orthogonal time frequency space (OTFS) modulation is an emerging technique with potential advantages for next-generation communications in high-mobility scenarios. However, the received signals undergo a power decrease due to the non-coherent superposition of all symbols transmitted through wireless channels. To tackle this issue, we propose an intelligent reflecting surface (IRS)-aided OTFS system, which leverages the IRS to enable coherent combination of the received signals. Considering the IRS-aided single-input single-output (SISO)-OTFS systems, we first jointly design the OTFS symbol frame structure and IRS phase shifts to coherently strengthen the received signal power. Building upon the above system design, a low-complexity iterative interference cancellation (IIC) detector is proposed, and its detection performance is analyzed. Numerical results are presented to validate the effectiveness of the system design and the proposed IIC detector.