Multi-Rate De-Spreading Code

An efficient methodology to construct direct sequence code division multiple access (DS-CDMA) de-coding scheme has been investigated. System correlation performance is provided and analyzed. Since the perfect orthogonal codes, such as Walsh code, are difficult to obtain massively in conventional DS-CDMA system. To increase the number of spreading code utilized in system, we usually adopt sub-orthogonal codes, such as Gold sequences. Although the number of codes is extensively increased, the multiple access interference (MAI) problem has to be treated more carefully. Especially while lots of users access the DS-CDMA system at the same time. In this study, we proposed a CDMA de-spreading scheme worked in receiver part The MAI can be treated efficiently in the proposed multi-rate de-spreading scheme.