Adaptive Beamforming and Power Allocation for OFDM Over Wireless Networks
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.
Therefore, we can achieve a better overall error probability with a fixed
total
power. A distributed iterative algorithm is used to jointly update the
transmission power
and the beamformer weights at each subchannel so that it can converge to
optimal
solution for both power and beamforming vectors at each subchannel. The
algorithm uses only
the interference measured locally by the transmitter. Unlike most of the
loading
algorithms which optimize the bit distribution and power allocated to
subchannels for a single
transmitter, this approach tries to optimize the power allocatoin and decrease
the interference
for the whole network.