A Blind Space-Time Constrained Minimum Output Energy Detector for DS-CDMA Communication System

In this paper, a blind space-time (ST) multiuser detector, called ST constrained minimum output energy (ST-CMOE) detector, is proposed. It can be viewed as an extension of the CMOE method ( Proc. Globecom, p. 379, 1994), and therefore it is immune to near-far effect. It processes the antenna array output jointly in spatial and temporal domain. Simulation results show that the proposed algorithm can outperform the space-CMOE detector proposed by Wang and Poor ( IEEE Trans. Signal Process. vol. 47, p. 2356, 1999) which process the received signal in spatial and temporal domain separately. It can also outperform the ST subspace detector proposed by Chkeif (IEEE Trans. Commun. vol. 48, p. 729, 2000), which, although processes the received signal jointly in spatial and temporal domains, suffers from the mismatch problem in the multipath environment. The simulation results also show that the proposed ST-CMOE detector can achieve the same performance as the training-based ST minimum-mean-square-error detector. In order to reduce the computational load and adapt to dynamic multiple-access channels, an adaptive algorithm is presented. The computational load of this adaptive detector is comparable to Hu´s method (IEEE Trans. Signal Process . vol. 52, p. 1862, 2004), while it does not require any initial training or channel estimation in the multipath environment. Simulation results show that the proposed adaptive ST-CMOE detector can work well in a dynamic multiple-access channel, where interferences may enter or leave the channel at any time