Simple space-time coded SS-CDMA systems capable of perfect MUI/ISI elimination

In this letter we propose a very simple strategy for combining space-time block coding (STBC) with code division multiple access (CDMA) to be used in single-user links or in broadcasting over time-dispersive channels. The proposed system provides the desired space diversity gain and is capable of perfect cancellation of multiuser interference (MUI) and intersymbol interference (ISI), using a very simple receiver structure. The advantage is obtained by simply incorporating cyclic prefixes in the user codes. We provide a theoretical analysis, verified via simulation results, and a comparison between CDMA and OFDMA systems incorporating STBC.