A Systematic Framework for the Construction of Optimal Complete Complementary Codes

The complete complementary code (CCC) is a sequence family with ideal correlation sums which was proposed by Suehiro and Hatori. Numerous literatures show its applications to direct-spread code-division multiple access (DS-CDMA) systems for inter-channel interference (ICI)-free communication with improved spectral efficiency. In this paper, we propose a systematic framework for the construction of CCCs based on $N$-shift cross-orthogonal sequence families ($N$-CO-SFs). We show theoretical bounds on the size of $N$-CO-SFs and CCCs, and give a set of four algorithms for their generation and extension. The algorithms are optimal in the sense that the size of resulted sequence families achieves theoretical bounds and, with the algorithms, we can construct an optimal CCC consisting of sequences whose lengths are not only almost arbitrary but even variable between sequence families. We also discuss the family size, alphabet size, and lengths of constructible CCCs based on the proposed algorithms

Golay Complementary Sequences Over the QAM Constellation

In this paper, we present new constructions for $M^{2}$ -QAM and $2M$ $Q$-$PAM$ Golay complementary sequences of length $2^n$ for integer $n$, where $M=2^{m}$ for integer $m$. New decision conditions are proposed to judge whether an offset pairs can be used to construct the Golay complementary sequences over constellation, and with the new decision conditions, we prove the conjecture 1 proposed by Ying Li~\cite{16}. We describe a new offset pairs and construct new $64$-$QAM$ Golay sequences based on this new offset pairs. We also study the $128$-$QAM$ Golay complementary sequences, and propose a new decision condition to judge whether the sequences are $128$-$QAM$ Golay complementary