GENERATION AND PROPERTIES OF NONLINEAR SHIFT REGISTER SEQUENCES

Abstract

Binary sequences generated from nonlinear feedback shift registers offer attractive possibilities in the area of secure communication and multiple access addressing: In this dissertation computer -simulation studies have been undertaken to provide better understanding of the method of generation and properties of such sequences. Different methods of f_a11 .length sequence generation has been discussed, and one of the methods have been adopted to generate th.e full length sequence with the corresponding aut000rrelation function. Some non—linear feedback logics have been designed to prove-de specified output sequence.. The distribution of sequence length and decomposition of cycles obtained from such sequence are compared with statistical model of sampling process yielding interesting results. Another important s'equence characterstic, complexity, has been calcula`d by implementation of algorithms available for the purpose. Out of these the algorithm suggested by, Massey L10 provides simpler and general evaluation of complexity.