Constructions of Binary Sequences with Almost Optimal Autocorrelation Magnitude

In this paper, five constructions of binary sequences with almost optimal autocorrelation magnitude are proposed. The first construction is to use an arbitrary ideal 2-level autocorrelation sequence. The other four constructions are based on some sequences and their modified versions. 2N2 interleaved sequences are used to get the sequences whose values of the autocorrelations are optimal except one points. And the distributions of the periodic autocorrelation functions of the resultant sequences are given. The results provide more choices for CDMA system and other applications.