An OTFS Waveform Based Delay-Doppler Domain Channel Sounding Method for High-Mobility Scenarios

Channel measurements are the prerequisite for the design of communication systems in high-mobility scenarios. Conventional channel sounding methods cannot directly obtain Doppler characteristics in such scenarios, making the development of new methods highly attractive. In this paper, we propose a delay-Doppler (DD) domain channel sounding method that utilizes an orthogonal time frequency space (OTFS) waveform as the excitation signal to extract the channel spreading function (CSF). Additionally, a practical fractional delay-Doppler estimation algorithm is proposed to enhance the precision of channel measurements. This method is implemented by a DD domain channel sounding system, which includes the entire process of transmitting, receiving and processing the OTFS signal. Based on this system, channel measurements are conducted for vehicle-to-everything (V2X) scenarios in urban areas. Statistical results, involving root-mean-square (RMS) delay spread and RMS Doppler spread are derived, which validate the effectiveness of the proposed method and provide realistic references for research on V2X communications.