Robust SLNR Downlink Beamforming Based on Markov's Inequality
This paper considers the Multi-User Multiple-Input and Multiple-Output (MU-MIMO) downlink system where each user is equipped with multiple receive antennas. Due to the inevitable channel imperfection, the system performance may degrade significantly. A robust Signal-to-Leakage-and-Noise Ratio (SLNR)-based beamforming is developed to provide robustness against channel uncertainties, which maximizes the expectation of the signal power and maintains a low probability of the severe leakage. Two types of errors are taken into account, that is, the estimation Gaussian error in Time Division Duplexing (TDD) system and the quantization error in Frequency Division Duplexing (FDD) system.