Synthesis of Typical Environments

Abstract

Envirornmental synthesis is defined as a procedure by which an electromagnetic enviromnent (including equipment types, numbers and deployments) is generated, based on partial information. There is a need for such syntheses since complete information in both current and future time periods will never be available. Another requirement arises when excessive computer time is a significant factor. Since environmental synthesis implies relatively coarse inputs and outputs, its use should be confined to those areas in which such outputs are justified. Two such areas include frequency allocation and equipment specifications, both of which involve future installations, whose location and time frame are not known precisely. Answers are required which will indicate, in general terms, whether an equipment will cause or experience harmful degradation due to unintentional interference. One type of answer, termed separation criteria, can indicate the minimum geographical spacing and/or frequency separation which will be necessary to permit two specific equipments (or equipment types) to operate in a compatible manner. There is a choice of sampling all possible environments or generating a series of typical environments. The latter approach seems more practical, economic, and meaningful. For, if a system can perform satisfactorily in a enviromnent, it will certainly operate in less congested situations. If it does not pass the worst case test, significant problem areas can be identified and a reasonable lower bound imposed. A number of statistical distributions are described, involving deployment of equipments, propagation effects, operating frequency, and antenna gain characteristics.