DESIGN OF KRONECKER AND COMBINATION SEQUENCES AND COMPARISON OF THEIRCORRELATION, CDMA AND INFORMATION SECURITY PROPERTIES

Two families of rapidly synchronizable spreading codes are compared us ing the same component codes. The influence of component code choice i s also discussed. It Is concluded that correlation, code-division mult iple-access (CDMA) and information security (measured by the value of linear complexity) properties of Kronecker sequences are considerably better than those of Combination sequences. Combination sequences cann ot be recommended for CDMA use unless the number of active users is fe w. CDMA performance of Kronecker sequences is almost comparable with t hat of linear pseudonoise (PN) code families of equal length when a Go ld or Kasami code is used as the innermost code and the Barker code is used as the outermost code to guarantee satisfactory correlation and CDMA properties. Kronecker sequences possess a considerably higher val ue of linear complexity than those of the corresponding non-linear Gef fe and majority logic type combination sequences. This implies they ar e highly non-linear codes due to the Kronecker product construction me thod. It is also observed that the Geffe type Boolean combiner resulte d in better correlation and CDMA performance than with majority logic. The use of the purely linear exclusive-or combiner for considerable r eduction of code synchronization time is not found recommendable altho ugh it results in good CDMA performance.