An Efficient Resource Allocation for Multiuser MIMO-OFDM Systems with Zero-Forcing Beamformer

In this paper, a low complexity subcarrier allocation scheme is proposed for multiuser MIMO-multiuser OFDM systems with zero-forcing beamforming (ZFBF) to minimize the total transmit power satisfying given target data rates of users. The ZFBF for multiuser MIMO makes multiple spatial channels by removing multiuser interference and the subcarrier allocation can be performed over spatial and frequency domain. Since the optimal method has very high computational complexity, the semi-orthogonal user selection (SUS) is employed to reduce the computational complexity. In numerical results, we show that the total transmit power satisfying the data rates of users is linearly decreased with the number of transmit antennas.