The Construction of GOS Spreading Code Sets and Their Applications into Multi-Rate Multe-Cell QS-CDMA Systems

Abstract

In this paper, a class of generalized orthogonal sequences (GOS) is presented with the the following characteristics, (1) the cross-correlations in the vicinity of zero shift (zero shift is excluded) between two arbitrary sequences from different GOS sets are zeros; (2) the cross-correlations in the vicinity of zero shift between two arbitrary sequences from different subsets of the same GOS set are zeros; and (3) two arbitrary different sequences from the same subset of the same GOS set are orthogonal. By applying the GOS sets to multi-rate multi-cell quasi-synchronous CDMA (QS-CDMA) system, the system interference is analyzed and compared with that of well-known concatenated orthogonal/PN sequence sets. It is shown that due to the zero correlation properties in the vicinity of zero shift, the interference of system employing GOS sets can achieve a bigger reduction than concatenated orthogonal/PN sequence sets, thus resulting better BER performance than that of latter under the same conditions.