Max-Min Beamforming Design for Heterogeneous Networks With Hardware Impairments

Due to the impact of amplifier nonlinearities and phase noise, practical transceivers in heterogeneous networks (HetNets) suffer different degrees of hardware impairments (HWIs), which can non-trivially distort the received signals even with signal compensations. Traditional beamforming methods in HetNets that neglect the residual impairments have been proved to cause performance degradation. To that end, we investigate a realistic beamforming design based on max-min fairness in a multi-cell multiple-input single-output HetNet with HWIs. The beamforming design problem is formulated as a non-convex optimization problem for maximizing the minimum transmission rate of the femtocell users while guaranteeing the quality of service of the users in both the macrocell and femtocells. Simulation results show that compared with the beamforming algorithm with perfect hardware, our proposed beamforming algorithm brings less interference power to the macrocell user and has good fairness.