  Orthogonal time frequency space (OTFS) is a modulation technique which is
robust against the disruptive effects of doubly-selective channels. In this
paper, we perform an experimental study of OTFS by a real-time software defined
radio (SDR) setup. Our SDR consists of a Graphical Processing Unit (GPU) for
signal processing programmed using Sionna and TensorFlow, and Universal
Software Radio Peripheral (USRP) devices for air interface. We implement a
low-latency transceiver structure for OTFS and investigate its performance
under various Doppler values. By comparing the performance of OTFS with
Orthogonal Frequency Division Multiplexing (OFDM), we demonstrate that OTFS is
highly robust against the disruptive effects of doubly-selective channels in a
real-time experimental setup.
