A computer-aided design methodology for digital line of sight links

The author describes a computer-based design methodology for digital line-of-sight (LOS) links, developed for engineering new digital microwave paths. First described are performance criteria for digital LOS links that provide the foundation for link design. Models of transmission losses for digital LOS links are given for rainfall attenuation; multipath fading, and dispersion. Enumerated are link design procedures that allow path parameters such as path clearance, system gain, rain margin, and various fade margins to be calculated, and equipment parameter values that will meet performance objectives to be selected. These link design procedures are incorporated into a computer program which permits the designer the flexibility to enter any equipment and path characteristics and calculate any link parameter. The unique feature of this approach is that the effects of all link losses are combined in a comprehensive calculation to ensure that link outage objectives are met. Finally, the program allows the user to iterate through the calculations for change of parameters aimed at maximizing performance or minimizing cost