The importance of initial-phase selection agreement of PN sequences from the standpoint of numerical analysis and simulation of a DS-CDMA system

The authors point out the need for fixed PN code sets for test purposes from the standpoint of numerical analysis and simulation of an asynchronous DS-CDMA system and its sub-system units. An agreement on test sequence sets and their initial phases for fixing the probability distribution function of the multiple-access interference (MAI) random variable is necessary in order to make the numerical performance results of different research groups and authors commensurable in large system design projects and in the CDMA literature. The conclusions are drawn from numerical examples of initial-phase optimization with the auto-optimal least side-lobe energy (AO/LSE), least side-lobe energy auto-optimal (LSE/AO), maximum side-lobe energy auto-optimal (MSE/AO), cross-optimal minimum mean-square cross-correlation (CO/MSQCC) and minimum mean-square cross-correlation cross-optimal (MSQCC/CO) criteria and by reviewing the literature. Optimization criteria are compared from the standpoint of minimum MAI. Conclusions are drawn from their order of quality and the conditions under which the optimization is practicable. Finally, some binary and quadri-phase PN code sets for fixing the MAI signal component for test purposes are reviewed.