Characterization of wireless communication channel based on scattering function

Almost all communication channels introduce dispersive or multiplicative disturbances which give rise to dispersive effects known as time selective fading and frequency selective fading. Scattering function can be used to characterize this channel in terms of time delay profile and Doppler spread. Doppler spread gives a measure in frequency variation where it introduces time selective fading. Frequency selective fading on the other hand is the effect of time delay spread in frequency domain where certain frequency components in the received signal spectrum have greater gains than the others. Channel scattering function is determined based on the ambiguity function and it is derived based on the Fourier transform relationship of the cross bilinear. Based on periodogram of the scattering function, time delay spread and Doppler spread can be determined. PSK and QPSK signals having duration of 0.512 sec are used for this purpose.