A Robust Secure Hybrid Analog and Digital Receive Beamforming Scheme for Efficient Interference Reduction

TL;DR

This paper introduces a robust hybrid analog and digital receive beamforming scheme that effectively reduces interference and is resilient to DOA estimation errors, improving SINR in large antenna arrays.

Contribution

It proposes a novel hybrid ADB scheme combining null space projection and diagonal loading to enhance robustness against DOA errors.

Findings

Improved SINR performance over existing schemes

Enhanced robustness to DOA estimation errors

Significant interference reduction in large antenna arrays

Abstract

Medium-scale or large-scale receive antenna array with digital beamforming can be employed at receiver to make a significant interference reduction, but leads to expensive cost and high complexity of the RF-chain circuit. To deal with this issue, a classic analog-and-digital beamforming (ADB) structure was proposed in the literature for greatly reducing the number of RF-chains. Based on the ADB structure, we in this paper propose a robust hybrid ADB scheme to resist directions of arrival (DOAs) estimation errors. The key idea of our scheme is to employ null space projection (NSP) in analog beamforming domain and diagonal loading (DL) method in digital beamforming domain. Simulation results show that the proposed scheme performs more robustly, and moreover, has a significant improvement on the receive signal to interference plus noise ratio (SINR) compared to NSP ADB scheme and DL method.