Lens-Based Beamformer for Low-Complexity Millimeter-Wave Cellular Systems

TL;DR

This paper explores lens-based beamforming techniques at 28 GHz for mmWave massive MIMO systems, aiming to reduce system complexity while maintaining performance through theoretical, electromagnetic, and prototype evaluations.

Contribution

It introduces and evaluates two lens-based beamforming topologies as a low-complexity alternative to traditional MIMO processing at 28 GHz.

Findings

Lens-based beamforming reduces system complexity.

Performance comparable to conventional MIMO methods.

Feasibility demonstrated through prototype testing.

Abstract

Data rate requirements for cellular communications are expected to increase 1000-fold by 2020, compared to 2010. This is mainly because of the rapid increase in the number of wireless devices and data hungry applications per-device. This creates a formidable bandwidth crisis. Milimeter-wave (mmWave) systems with massive multiple-input multiple-output (MIMO) operation are two complementary concepts poised to meet this exploding demand, as verified by the wealth of investigations by both industry and academia. Nevertheless, existing MIMO processing techniques, requiring a dedicated radio-frequency (RF) up/down-conversion chain per antenna, results in prohibitively high complexity and cost of the mmWave prototypes. The primary objective of this paper is to present a complete feasibility study on alternative beamforming techniques targeted to reduce the system complexity without drastically compromising its performance. More precisely, at 28 GHz, we investigate the end-to-end performance of two different lens-based beamforming topologies. Our study is an amalgam of theoretical modelling, electromagnetic design, and prototype manufacturing, yielding a comprehensive mmWave, massive MIMO performance evaluation.