DS/CDMA signature sequences based on PR-QMF banks

In this paper, we propose two classes of multivalued signature sequences for direct sequence code division multiple access (DS/CDMA) systems. The proposed classes are obtained from the coefficients of the subbands of perfect reconstruction quadrature mirror filterbanks (PR-QMF). The first and second classes are derived from the tree and lattice structure PR-QMF banks, respectively, and they both have perfect correlation properties for synchronous DS/CDMA systems. The second class, in addition, has generally better correlation properties than other well-known sequences in asynchronous DS/CDMA systems. Some numerical results for the performance of the asynchronous DS/CDMA systems with several sequences, including the second class of sequences, are obtained.