LMS Adaptive Receiver for Uplink Space-Time Coded MC-CDMA Systems

In this paper, we propose a least mean square (LMS) adaptive receiver for uplink multicarrier code-division multiple access (MC-CDMA) systems employing Alamouti's simple space-time block coding (STBC). In general, for the space-time coded systems, there are two filters to be designed, where one is for detecting odd-indexed symbols and the other for even-indexed symbols. In the proposed scheme, the two filters are independently updated and convergence properties such as convergence condition, time constant, and steady-state excess mean-squared error (MSE) are analyzed. Simulation results show that the proposed LMS adaptive receiver has higher steady-state signal to interference and noise ratio (SINR) than the LMS adaptive receiver for the MC-CDMA system with single transmit antenna while the former shows slower convergence rate than the latter.