SEQUENCES FOR FREQUENCY HOPPED SPREAD SPECTRUM SYSTEMS

Abstract

Communication systems which employ frequency hopped spread spectrum (FH-SS) techniques as a means of supporting multiple users need large families of code sequences such that interference from other users is minimum. Also the -codes should be long enough to avoid the threat of intentional jamming. Normally frequency hopping sequences are obtained by selecting groups of elements of binary m-sequences, but this does not have all the desired properties. A number of alternative sequence designs have been proposed by many authors. In this dissertation salient features of FH-SS system have been discussed and the necessity of `good' sequences and criteria of `goodness' have been established. Generation methods and mathematical basis of various families of sequences viz non-binary m-sequences over a prime extension field, one-coincidence sequences, sequences with optimum Hamming correlation properties, sequences derived from generalized bent function-sequences and Reed-Solomon code words have been reviewed. A number of such sequences have been generated and the properties viz, Hamming cross-correlation, autocorrelation, number of sequences and linear span have been ver