Simulation of time-varying, frequency-selective multipath fading channels for spread-spectrum waveforms

A channel simulator appropriate for arbitrary spread-spectrum waveforms transmitted over arbitrary time-varying, frequency-selective multipath Rayleigh fading channels has been developed and implemented. Both Doppler (or time) diversity and delay (or frequency) diversity are considered in the channel model on which the simulator is based. The channel is assumed to be a time-varying Gaussian channel that obeys the uncorrelated scattering assumption. The model developed consists of multiple Doppler-shifted branches of tap-delay lines. No assumptions are made about the independence of channel taps. Simulation results for flat slow fading, flat fast fading, frequency-selective slow fading and frequency-selective fast fading examples are presented.