FINITE DATA PERFORMANCE ANALYSIS OF MVDR ANTENNA ARRAY BEAMFORMERS WITH DIAGONAL LOADING

Diagonal loading has been regarded as an e-cient manner to tackle the flnite sample efiect or the steering vector imprecision problem on adaptive array beamforming. However, the reason of the robustness improvement by the loading factor is still unknown and rarely discussed. In this paper, we consider the flnite sample efiect and derive the approximated output signal-to-interference-plus-noise ratio (SINR) of minimum variance distortionless response (MVDR) beamformers with diagonal loading. The obtained SINR expression is more explicit and compact than the existing formulas in the literature. Based on the theoretical results, we investigate the efiects of a loading factor on the output SINR of MVDR beamformers. The theoretical analysis shows the efiectiveness of diagonal loading on alleviating flnite sample efiect. Moreover, the price of using diagonal loading is also discussed. Simulation results are presented for conflrming the validity of the research work.