Accession Number : ADP006287

Title :   Knowledge-Based Fading Channel Analyzer for Adaptive Radio Links,

Corporate Author : SRS TECHNOLOGIES HUNTSVILLE AL

Personal Author(s) : Yalowitz, Jeffrey S. ; Baird, Frank G. ; Morrison, James M.

Report Date : 03 MAY 1990

Pagination or Media Count : 10

Abstract : A new analysis technique proposed for fading radio channels combines object-oriented, knowledge-based processing algorithms with conventional quantitative methods to provide on-line estimates of channel dynamics and permits real-time formulation of adaptive link control strategies. Temporal features of a digitized signal envelope power record from the receiver are classified by statistical properties and threshold crossing behavior into elemental descriptive objects (e.g., increasing signal, decreasing signal), which have both symbolic and parametric attributes. An expert-system inference engine operates on the elemental objects to construct more complex descriptive objects that characterize complete signal fade waveforms and fading sequences. Techniques are being developed to appress additional rules and statistical system identification procedures to generate multipath propagation models can be used to derivation of adaptive equalization and link control directives. The proposed technique integrates use of automated heuristic procedures and adaptive signal processing to permit effective interpretation of channel conditions in cases where time and information are limited. Applications of knowledge-based ionospheric propagation analysis include adaptive HF communications links, ionospheric monitoring, and over-the-horizon radar.

Descriptors :   *IONOSPHERIC PROPAGATION, *FADING(ELECTROMAGNETIC WAVES), RADIO LINKS, ADAPTIVE SYSTEMS, CHANNELS, DIGITAL SYSTEMS, ALGORITHMS, MULTIPATH TRANSMISSION, OVER THE HORIZON RADAR.

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE