The multipath channel transfer function dynamics: measurements and theoretical considerations

Frequency selective fading due to multipath propagation is a major cause of impairment affecting line of sight digital radio relay links. In spite of the great interest devoted by many authors to the study of the static transfer function of the multipath channel, little material has been published on the dynamic of its characteristic parameters. Such information are needed for the improvement of existing performance prediction methods for digital radio relay links and for the equipment design such as equalizers and combiners. The basis of the article are the measurements performed on a digital radio link located in northern Italy. The transfer function is described in terms of the most relevant static and dynamic features and the parameters of the simplified three rays channel model are studied in connection to the experimental data