Spatial Precoding and Loading for Multi-User Mutiple-Antenna OFDM Systems

In this paper we investigated interference pre-subtraction problems in multi-users downlink channel for multiple-antennas OFDM system, in which the number of users is larger than the number of transmit antennas. We present a new jointly spatial loading and preceding strategy to select reasonably a group of users for each tone on each transmit antenna by maximizing signal to interference and noise ratio (SINR), Then we introduce vector perturbation preceding in order to cancel multi-users interference at transmitter and achieve the maximum capacity or the minimum BER. Compared with conventional channel inversion and regularization channel inversion method, our proposed method has demonstrated a better performance than other methods because of multi-users diversity gain. Moreover, the proposed method would not increase peak-to-average power ratio (PAPR) of systems