On the use of discrete Wavelet Transform for resolving Channel Impulse Response

This paper presents a new Discrete Wavelet Transform (DWT) based technique for resolving multipath components in Channel Impulse Response (CIR). CIR is calculated from channel transfer function (CTF) using Inverse Fast Fourier Transform (IFFT). CTF for scattering from building faces modeled semi-deterministically is found using Method of Moments (MoM). As the CTF is calculated in limited frequency band therefore the time resolution in the CIR is limited. Hence the contributions from scattering centers located in close proximity to each other cannot be identified. In order to overcome this problem DWT as a Quadrature Mirror Filter (QMF) bank is applied to extract the major components in the CIR. Simulation results indicate that DWT can be used to identify the various contributions in the CIR especially the very weak diffracted field components. Results were validated using geometrical optics to verify the proposed technique.