OTFS modulation and PAPR reduction for IoT-railways

Abstract

The internet of things (IoT) has been widely considered to be integrated with high-speed railways to improve safety and service. It is important to achieve reliable communication in IoT for railways (IoT-R) under high mobility scenarios and strict energy constraints. Orthogonal time frequency space (OTFS) modulation is a two-dimensional modulation technique that has the potential to overcome the challenges in high Doppler environments. In addition, OTFS can have lower peak-to-average power ratio (PAPR) compared to orthogonal frequency division multiplexing, which is especially important for the application of IoT-R. Therefore, OTFS modulation for IoT-R is investigated in this paper. In order to decrease PAPR of OTFS and promote the application of OTFS modulation in IoT-R, the peak windowing technique is used in this paper. This technique can reduce the PAPR of OTFS by reducing the peak power and does not require multiple iterations. The impacts of different window functions, window sizes and clipping levels on PAPR and bit error rate of OTFS are simulated and discussed. The simulation results show that the peak windowing technique can efficiently reduce the PAPR of OTFS for IoT-R.