Constructions of Optimal and Near-Optimal Quasi-Complementary Sequence Sets from an Almost Difference Set

TL;DR

This paper presents a method to construct near-optimal quasi-complementary sequence sets for multicarrier CDMA, enabling support for exponentially more users by leveraging almost difference sets and quaternary sequences.

Contribution

It introduces a novel construction of near-optimal QCSSs using an optimal quaternary sequence set and an almost difference set, improving user capacity in CDMA systems.

Findings

Supports exponentially more users in CDMA systems

Can achieve asymptotic optimality with parameter adjustments

Demonstrates practical construction of near-optimal QCSSs

Abstract

Compared with the perfect complementary sequence sets, quasi-complementary sequence sets (QCSSs) can support more users to work in multicarrier CDMA communications. A near-optimal periodic QCSS is constructed in this paper by using an optimal quaternary sequence set and an almost difference set. With the change of the values of parameters in the almost difference set, the near-optimal QCSS can become asymptotically optimal and the number of users supported by the subcarrier channels in CDMA system has an exponential growth.