NTIA Report 92-283

An Analysis of Reception Variability Due to Terrain Multipath
on Microwave Common Carrier Links

January 1992

E. J. Dutton, T. G. Hoople, and M. P. Roadifer

Abstract: The error variability of received PSK (MSK), QAM and QPR modulations on digital microwave common carrier links resulting from transmitted power variations and the dispersive effects of terrain multipath using a two-ray model is analyzed. These results and an earlier prediction of long-term (annual) average symbol error rate (SYE) for the above modulations are used to predict median annual received symbol error rate. Since the average SYE was used earlier to represent median conditions, average and new median SYE’s are compared.

Year-to-year variability of received power and BER of common carrier microwave transmissions caused by variation of annual refractivity gradient distributions on off-axis paths is also analyzed, and it is concluded that this variability is not significant vis-à-vis the annual variability discussed above.

Keywords: digital modulation; error rate variability; microwave links; reception variability; refractivity gradient distributions; terrain multipath

• Report

Disclaimer: Certain commercial equipment, components, and software are identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.