New Correlation Bound and Construction of Quasi-Complementary Code Sets

Quasi-complementary code sets (QCCSs) have attracted sustained research interests for simultaneously supporting more active users in multicarrier code-division multiple-access (MC-CDMA) systems compared to complete complementary code sets (CCCSs). In this paper, we investigate a novel class of QCCSs composed of multiple CCCSs. We derive a new aperiodic correlation lower bound for this type of QCCSs that is tighter than the existing ones and present a systematic construction of such QCCSs with a small alphabet size and low maximum correlation magnitude. We also show that the constructed aperiodic QCCSs can meet the newly derived correlation lower bound asymptotically.