Space-time correlation theory for information-carrying signals

Abstract

A theory is presented for the analysis and optimization of systems which process electromagnetic fields carrying information. The theory is thus intended for use primarily by communications and radar engineers. The definitions are motivated by a fundamental requirement that the input-output space-time mutual information transfer be a maximum. The theory can be applied to problems involving nonstationary and nonergodic processes in space and time. The technique proposed is particularly useful in the analysis and optimization of controlled systems carrying man-made information, such as radar and communications. System optimization is carried out by maximization of the trans-correlation function with respect to the variable parameters of the system. The transcorrelation function is a space- and time-averaged correlation function between the desired and the actual system outputs. The optimization technique is applied to the problem of an antenna embedded in a nonstationary medium, such as a hot plasma. The amplitude and phase shading of the array are the variable parameters chosen for optimization of the system, and medium effects, background (object) noise, receiver noise, etc., are considered.