The Technology Potentials for Satellite Spacing and Frequency Sharing

In this analysis of the factors influencing satellite spacing and frequency sharing, system parameter constraints are derived that could improve the compatibility of satellite and microwave relay systems sharing a common spectrum. Three types of stations are considered in analyzing spectrum sharing: terrestrial microwave repeaters and terminals, satellite repeaters, and earth-station terminals. There are nine possible direct interference modes for this sharing situation, and two potentially important scatter interference modes that involve the intersection of the main beam of an earth station with the main beam of a microwave relay station. Although some of the interference modes are not experienced in current operations, the possibility of being able to double the equivalent spectrum available makes it important to consider the use of some portions of the spectrum for both up and down links to satellites. The technical and technological background needed to derive suitable specifications for high-performance system design is outlined. The joint constraints imposed on the various system parameters are then derived, and the technological potentials for satellite spacing and frequency sharing are defined. (See also RM-5786.)