Bypassing Channel Estimation for OTFS Transmission: An Integrated Sensing and Communication Solution

In this paper, we develop a novel downlink transmission scheme for vehicular networks based on integrated sensing and communication (ISAC) signals and orthogonal time frequency space (OTFS) modulation. Based on the ISAC-OTFS signals, the roadside units (RSUs) are capable of estimating various motion-related parameters, such as the locations and speeds of vehicles based on the reflected echoes, which are further exploited for predicting the delay-Doppler domain downlink channel parameters. Consequently, the RSU can create effective transmit beamformers which can compensate the channel path loss and Doppler shift before transmitting the ISAC signal while the vehicles can bypass the channel estimation for downlink transmission. Through numerical results, we verify the effectiveness of the proposed scheme.