Iterative method for extracting impulse response of a RF channel with its band-limited transfer function

Channel modeling is very important for wireless system designs, especially in a radio harsh environment. The impulse response is a key quantity that characterizes the time-domain properties of a RF channel. One of the conventional ways to obtain a channel impulse response is to measure the channel frequency-domain transfer function with a vector network analyzer and then convert the measured transfer function into its time-domain impulse response through the inverse Fourier transform. However, because the transfer function can practically be measured only within a finite frequency band, the obtained impulse response is often not causal and not very accurate with high resolutions. In this paper, we propose a Hilbert transform based iterative method to expand and extrapolate the transfer function beyond its measured frequency band and thus s highly-resolved causal impulse response of a RF channel can be obtained.