A per-carrier semiblind multiuser receiver for SFBC downlink MIMO MC-CDMA systems

This paper proposes a per-carrier (PC) frequency-domain semiblind multiuser receiver for space-frequency block code (SFBC) downlink multiple-input multiple-output (MIMO) multi-carrier code division multiple access (MC-CDMA) with common pilot channel (CPICH) system where optimal pilot-to-data power ratio (PDPR) is considered. The receiver exploits the advantage of equalising for each carrier separately. The diversity from space-frequency (SF) and MIMO techniques passing formulated SF received multiuser shifted block signal sequence matrix can operate in systems with sufficient, insufficient or even without cyclic prefix (CP). The updated algorithm is based on projection to the subspace spanned by the pilot and the desired user spreading codes, and updated at the block level (low rate). Numerical results show that the proposed receiver significantly outperforms single-carrier (SC) semiblind and SC pilot-based receivers in MIMO fast time varying multipath frequency-selective fading channel with Doppler.