A Novel MUI-Free VSF-MC-CDMA Architecture for WLANs

In this paper we generalize the traditional Walsh code to a novel spreading code, whose ideal spectral correlation properties can be utilized in MC-CDMA system to resist multiuser interference (MUI) under multipath channel conditions. We also propose the application style of the new spreading code in MC-CDMA, so that the system not only provides MUI-free performance, but also supports multi-rate services flexibly by using spreading codes with variable-spreading-factor. These advantages make the proposed MC-CDMA system a promising candidate for future WLANs. Both theoretical analysis and simulation results indicate that the proposed system has better BER performance than traditional Walsh code based MC-CDMA, and has higher capacity than the MUI-free MC-CDMA in Ref. [6] under most channel conditions.