Optimal Polyphase Asymmetric ZCZ Sequence Sets Including Uncorrelated Sequences

Abstract

The present paper proposes a new method for constructing polyphase asymmetric zerocorrelation zone (A-ZCZ) sequence sets using discrete Fourier transform (DFT) matrices and orthogonal codes. The proposed method can generate A-ZCZ sequence sets that cannot be obtained using known methods. The newly obtained A-ZCZ sequence sets include optimal ZCZ sequence sets. In addition, two arbitrary sequences that belong to different sequence subsets become uncorrelated sequences. The proposed method is expected to be useful for reducing or avoiding inter-cell interference from adjacent cells in approximately synchronized code-division multiple-access (AS-CDMA) systems.