Fractional delay modeling in multipath fading channels with time-varying propagation delays

Realistic modeling of channel environments is essential for the design and performance evaluation of wireless communication systems. Wireless signals undergo fading due to factors such as path loss, multipath propagation, and the Doppler effect. Such fading can significantly degrade the received signal quality, thereby reducing the system's robustness and efficiency. Channel models that accurately capture the characteristics of real-world wireless environments enable the evaluation of realistic performance and the development of optimized algorithms. In performance simulations, multipath power and delay profiles are typically required to account for fading channels. Conventional models often quantize path delays as integer multiples of the signal sampling interval for simplicity and convenience. However, in high-speed environments, such as a low-Earth orbit (LEO) satellite non-terrestrial network (NTN), time-varying propagation delays necessitate consideration of fractional delays within the sampling interval. This paper investigates several interpolationbased fractional delay modeling methods for multipath channels with time-varying propagation delays and compares their performance.