Sequences with large ZCZ

The paper describes the construction and properties of a new class of sequences. The construction relies on the decomposition of m-sequences into arrays where each column is a cyclic shift of a shorter m-sequence or constant. The m-sequence columns are replaced by suitable sequences of the same length. Three examples of such substitution are presented: complex Legendre sequence, modified Zech logarithm sequence, and Walsh-Hadamard sequences. Constant columns are replaced by all 0s (magnitude). The arrays are then unfolded to form long sequences. These sequences have a large zero correlation region around the autocorrelation peak. Many large sets of these sequences can be constructed, such that their cross-correlation is also zero in this region. Such sets are required for quasi-synchronous CDMA.