Software-Defined Radio Experimental Validation of an OTFS-Based ISAC for Velocity Estimation in an ARoF Setup

OTFS, proposed for next-generation wireless communication systems such as 6G mobile networks, incorporates ISAC into DD-domain multiplexing, enabling simple detection of distance, velocity, and movement direction. This paper presents a SDR implementation of OTFS in an ARoF setup with wireless RF transmission. The main goal of this study is to validate and evaluate the implemented OTFS with static objects and to explore the quality of velocity and direction estimation in sensing scenarios involving moving objects. For the BER measurements, experiments were performed using a static object while varying the SDR transmitter power and introducing additional CFO. Experimental validation shows a minimum BER ≤ 5 × 10−7 with 0 errors per 2 × 106 bits. Data transmission at fractional Doppler yielded a BER ≈ 0.09, which is attributed to the use of a LMMSE channel estimator, that is not optimal for channels with fractional Doppler. Estimation of the velocity of a mobile object with an absolute velocity of |v|=0.15 m/s yielded a RMSE = 0.0839 m/s.