Amin Aliabadi - Department Of electronic,Malayer branch,Islamic Azad University,Malayer,IranMsc in the telecommunication-engineering
Hedyeh Ghafari
Gholnaz Sanjabi

In this paper, we examine the multiuser detection for quasi-synchronous multi-carrier code-division multiple-access (MC-CDMA) multiple-input multiple-output (MIMO) Systems with space–time block codes (STBC). Considering Alamouti's STBC scheme which involves two transmit and multiple receive antennas, the Hermitical per symmetric- Like property of the received signal is derived first. The forward–backward averaging technique and weighting analysis are then proposed for the blind constrained minimum output energy (CMOE), subspace-based and diagonal loading (DL)-based CMOE receivers. The forward–backward averaging technique, which uses twice the equivalent STBC blocks to design the multiuser receivers, reduces the bit-error-rate (BER) tremendously for the compared receivers. Besides, the weighting analyses are performed in which half of the computational cost is saved in the calculation of weight vectors. Finally, numerical simulations are given to evaluate and demonstrate the superiority of the multiuser receivers with forward–backward averaging technique and the correctness of weighting analyses.& 2008 Elsevier B.V. All rights reserved.

MIMO system, MC-CDMA, STBC, Blind channel estimation, Constrained minimum output energy, receiver, Forward–backward averaging technique