Robust Multiuser Downlink Beamforming with Per Antenna Power Constraints using Worst-Case Performance Optimization

We propose a robust solution to the problem of multiuser downlink beamforming with constraints on per antenna power and quality of services (QoS). We assume only the erroneous channel state information (CSI) is available at the transmitter, which may arise due to quantization, feedback delay, feedback error, etc., and solve this problem within the framework of worst-case performance optimization. Simulations results confirm that the worst-case based robust solution outperforms the existing non-robust solutions and satisfies the QoS constraints with probability one while the non-robust scheme satisfies the QoS only with an outage probability of 0.5.