Low Complexity Adaptive Beamforming and Power Allocation for OFDM Systems

In this paper, the performance of a multiuser wireless network using OFDM, combined with Power Control and Adaptive BeamForming for uplink transmission is presented. An adaptive power control algorithm is exploited to acheive the desired Signal to Noise Ratio(SNR) at each subchannel and increase the power efficeincy of the transmitter mobile. In the receiver side, the base station uses an antenna array to optimize the SNR-Power efficeincy, and attenuate the interference from other users dramatically. However, in this paper the subchannels are not considered separately. A procedure tries to minimize the interference in all of the subchannels simultaneousely. The bit error rate is very similar to the case when ther are independent, but the complexity in the receiver is much lower, because the FFT procedure is not being performed at each antenna.