Optimum Hybrid MVDR Beamformer With Sparse Signal Recovery Approach

Hybrid beamforming (HBF) reduces power consumption and transceiver complexity by employing a small number of radio frequency (RF) chains compared to the available antenna elements. The goal is to design HBF to achieve similar or close performance to that with the full digital beamforming (DBF), where an RF chain is employed per antenna element. This paper proposes hybrid receive beamformer optimization under a framework of minimum variance distortionless (MVDR) beamformer, leveraging the sparse signal recovery concept.We analytically show the optimality of the proposed approach. Computer simulations are used to compare the proposed HBF approach with DBF in terms of beampatterns and signal-to-noise-and interference (SINR). The results validate the analytical solution and illustrate that HBF delivers similar performance to full DBF, and only becomes inferior if the number of RF chains is much smaller than the number of antenna elements.