RF Lens-Embedded Massive MIMO Systems: Fabrication Issues and Codebook Design

TL;DR

This paper explores RF lens-embedded massive MIMO systems at 77 GHz, demonstrating fabrication, experimental validation, and a novel codebook design that significantly improves system performance over traditional setups.

Contribution

It introduces a fabrication process for RF lenses at mmWave frequencies, verifies their focusing properties experimentally and through simulation, and proposes a new codebook design tailored for RF lens characteristics.

Findings

RF lens exhibits proper amplitude gain and focusing properties

Proposed MVCQ codebook enhances limited feedback performance

System performance surpasses conventional massive MIMO without RF lens

Abstract

In this paper, we investigate a radio frequency (RF) lens-embedded massive multiple-input multiple-output (MIMO) system and evaluate the system performance of limited feedback by utilizing a technique for generating a suitable codebook for the system. We fabricate an RF lens that operates on a 77 GHz (mmWave) band. Experimental results show a proper value of amplitude gain and an appropriate focusing property. In addition, using a simple numerical technique--beam propagation method (BPM)--we estimate the power profile of the RF lens and verify its accordance with experimental results. We also design a codebook--multi-variance codebook quantization (MVCQ)--for limited feedback by considering the characteristics of the RF lens antenna for massive MIMO systems. Numerical results confirm that the proposed system shows significant performance enhancement over a conventional massive MIMO system without an RF lens.