Interference in a Dense Radio Network

The major factor influencing the design of radio systems above 10 GHz is the attenuation caused by rainfall; the principal result, from which many other prameters are determined, is that the repeaters must be closely spaced compared with lower frequency systems.1'2 Consequently, the number of exposures to co-channel interference may be large--requiring interference resistant modulation. Such solutions generally use considerable bandwidth, thus raising questions about the efficiency of frequency occupancy. The uses for short hop systems are such that many systems may exist in the same area on the same frequency assignment. Among the possible applications are broadband exchange area service, Picturephone® visual telephone distribution, and communication between mobile telephone concentrators. The important property with respect to efficient spectrum usage is the total "communication capacity through the area" in a given bandwidth. It is conceivable that, in terms of the concept of capacity through an area, interference resistant wideband modulation is more efficient than the narrowband 1727