COMPUTER-MODELS FOR FADING CHANNELS WITH APPLICATIONS TO DIGITAL TRANSMISSION

This paper describes computer models for Rayleigh, Rician, log-normal, and land mobile satellite fading channels. All computer models for the fading channels are based on the manipulation of a white Gaussian random process. This process is approximated by a sum of sinusoids with random phase angle. These models compare very well with analytical models in terms of their probability distribution of envelope and phase of the fading signal. For the land mobile satellite fading channel, results of level crossing rate and average fade duration are given. These results show that the computer model can provide a good coarse estimate of the time statistic of the faded signal. They also show that a 3-pole Butterworth shaping filter should be used with the model. These computer models well be useful in computer-aid modeling of communication systems under fading conditions. An example of the application of the land mobile satellite fading channel model to predict the performance of a DPSK signal is described.