Abstract:
The use of massive multiple-input multiple-output (MIMO) base stations in heterogeneous
networks (HetNets) offers an increase in throughput without increasing the bandwidth, but with reduced
power consumption. In this paper, we investigate the optimization problem of signal-to-interference-plusnoise
ratio balancing for the case of imperfect channel state information at the transmitter. We present a
fast converging robust beamforming solution for macrocell users in a typical HetNet scenario with massive
MIMO at the base station. The proposed method applies the matrix stuf ng technique and the alternative
direction method of multipliers to give an ef cient solution. Simulation results of a single-cell heterogeneous
network show that the proposed solution yields performance with modest accuracy, while converging in an
ef cient manner, compared with optimal solutions achieved by the state-of-the-art modeling languages and
interior-point solvers. This is particularly for cases when the number of antennas at the base station increases
to large values. This makes the solution method attractive for practical implementation in heterogeneous
networks with large-scale antenna arrays at the macrocell base station.
