Signal Processing Design of Low Probability of Intercept Waveforms via Intersymbol Dither

<p>This thesis investigates a modification to Differential Phase Shift Keyed modulation to create a low Probability of Interception/Exploitation communications signal. A Pseudodorandum timing offset is applied to each symbol in the communications stream to intentionally create intersymbol interference that hinders accurate symbol estimation and bit sequence recovery by a non-cooperative receiver. Two cooperative receiver strategies are proposed to mitigate the ISI due to symbol timing offset: a modified minimum Mean Square Error equalization algorithum and a multiplexed bank of equalizer filters determined by an adaptive Least Mean Square algorithum. Numermical simulation is used to demonstrate the bit error rate performance of cooperative receiversand notional non-cooperative receivers. Simulation results suggest that proper selection of pulse of pulse shape and probability distribution of symbol timing offsets produces a waveform that is accurately demonstrated by the proposed cooperative receivers and significantly degrades non-cooperative receiver symbol estimation accuracy.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>