Smart antenna and non-feedback IF equalization techniques for LEO satellite communications in a complex interference environment

An improved performance smart diversity system in conjunction with an IF non-feedback equalizer was invented to improve the signal performance in a combined selective fading, Additive White Gaussian Noise (AWGN), Co-channel interference (CCI) and Doppler shift environment like the LEO satellite channel. It is also applicable to aeronautical and telemetry channels. Smart diversity refers to a mechanism which selects the best branch at each moment based on the error quality with no default branch and no prioritization. The predominant novelty of my discovery in smart diversity is the introduction of multi level analog based Pseudo Error Detectors in every branch. In the smart diversity presented here there is no prioritized default branch/branches as opposed to Feher's smart diversity with single monitoring and a single default branch. Feher's diversity had many novel ideas and advantages over its predecessors. Similarly, the smart diversity presented here provides many improvements over the Feher's smart diversity which is critically compared in this dissertation. All components of the smart diversity were implemented in hardware as well as simulated in software using real time dynamic simulation techniques.; This research was motivated by problems caused by selective fading in LEO satellite systems due to low orbit and high relative speed with respect to the ground stations. Both the smart diversity and the IF non-feedback equalizer are independent of the modulation techniques and are applicable to both coherent and non-coherent detections. Although applicable to any modulation technique, FQPSK was used due to its spectral efficiency. Research was conducted in several related areas with the smart diversity system being the most important.