Joint downlink beamforming and space-time block coding for DS-CDMA systems in frequency selective fading channel

A downlink beamforming combined space-time coding and power control scheme for DS-CDMA systems in frequency selective fading channel is presented in this paper, in which the space-time coding is implemented by using two array antennas and the beamforming weights and transmitted power vector are obtained by an iterative algorithm such that the whole radiated power is minimized while the signal-to-interference and noise (SINR) requirements is maintained. Then a simplified algorithm for decreasing the complexity due to the existence of multipaths is suggested using equivalent one-path channel vector (EOCV) to replace multipath vectors. Simulations compare the performance between conventional space-time coding scheme and our method.