Analysis and Realization of an Exponentially-Decaying Impulse Response Model for Frequency-Selective Fading Channels

We analyze a simple frequency-selective fading model that is formulated as a sequence of independent discrete-time impulse responses, each with independent Gaussian variates scaled by an exponential power-delay profile. This model is useful for simulating propagation path responses in a scattering environment. Various expressions and relationships are derived for the frequency correlation function, correlation bandwidth, rms delay spread, and decay time. Realization techniques are also discussed, and it is concluded that the most straightforward and efficient approach is to generate a block of samples by multiplying i.i.d. complex Gaussian variates by the square root of the exponential power-delay profile and then taking the FFT.