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Ray Antenna Array: A Novel Cost-Effective Multi-Antenna Architecture for Enhanced Wireless Communication

Zhenjun Dong, Zhiwen Zhou, Yong Zeng

TL;DR

The paper addresses the high hardware cost of large-scale MIMO in next-generation networks by replacing phase shifters with a Ray Antenna Array (RAA) that uses many inexpensive antenna elements organized into ray-structured sULAs. A ray selection network dynamically connects a subset of sULAs to a small number of RF chains, while careful ray orientations and an MMSE-based joint beamforming/ray-selection scheme enable directed beams and high spatial resolution. The authors derive an orientation rule $\eta_n= n\arcsin(2/M)$, analyze hardware-cost benefits versus traditional HBF, and propose a low-complexity greedy algorithm with $O(NN_{RF})$ complexity that approaches exhaustive performance. Simulation results demonstrate substantial cost savings and performance gains, especially when using directional antenna elements, indicating RAA as a practical, scalable solution for 6G-era MIMO systems and sensing applications.

Abstract

This paper proposes a novel multi-antenna architecture, termed ray antenna array (RAA), which aims to enhance wireless communication performance in a cost-effective manner. RAA is composed of massive cheap antenna elements and a few radio frequency (RF) chains. The massive antenna elements are arranged in a novel ray-like structure, with each ray corresponding to a simple uniform linear array (sULA) with a carefully designed orientation. The antenna elements of each sULA are directly connected to an RF combiner, so that the sULA in each ray is able to form a beam towards a direction matching the ray orientation without relying on any analog or digital beamforming. By further designing a ray selection network (RSN), appropriate sULAs are selected to connect to the RF chains for further baseband processing. Compared to conventional multi-antenna architectures like hybrid analog/digital beamforming (HBF), the proposed RAA has two major advantages. First, it can significantly reduce hardware costs since no phase shifters, which are usually expensive especially in high-frequency systems, are required. Besides, RAA can greatly improve system performance by configuring antenna elements with higher directionality, as each sULA only needs to be responsible for a portion of the total coverage angle. To demonstrate such advantages, in this paper, we first present the input-output model for RAA-based wireless communications, based on which the ray orientations of the RAA are designed. Furthermore, efficient algorithms for joint ray selection and beamforming are proposed for single-user and multi-user RAA-based wireless communications. Simulation results demonstrate the superior performance of RAA compared to HBF while significantly reducing hardware cost.

Ray Antenna Array: A Novel Cost-Effective Multi-Antenna Architecture for Enhanced Wireless Communication

TL;DR

The paper addresses the high hardware cost of large-scale MIMO in next-generation networks by replacing phase shifters with a Ray Antenna Array (RAA) that uses many inexpensive antenna elements organized into ray-structured sULAs. A ray selection network dynamically connects a subset of sULAs to a small number of RF chains, while careful ray orientations and an MMSE-based joint beamforming/ray-selection scheme enable directed beams and high spatial resolution. The authors derive an orientation rule , analyze hardware-cost benefits versus traditional HBF, and propose a low-complexity greedy algorithm with complexity that approaches exhaustive performance. Simulation results demonstrate substantial cost savings and performance gains, especially when using directional antenna elements, indicating RAA as a practical, scalable solution for 6G-era MIMO systems and sensing applications.

Abstract

This paper proposes a novel multi-antenna architecture, termed ray antenna array (RAA), which aims to enhance wireless communication performance in a cost-effective manner. RAA is composed of massive cheap antenna elements and a few radio frequency (RF) chains. The massive antenna elements are arranged in a novel ray-like structure, with each ray corresponding to a simple uniform linear array (sULA) with a carefully designed orientation. The antenna elements of each sULA are directly connected to an RF combiner, so that the sULA in each ray is able to form a beam towards a direction matching the ray orientation without relying on any analog or digital beamforming. By further designing a ray selection network (RSN), appropriate sULAs are selected to connect to the RF chains for further baseband processing. Compared to conventional multi-antenna architectures like hybrid analog/digital beamforming (HBF), the proposed RAA has two major advantages. First, it can significantly reduce hardware costs since no phase shifters, which are usually expensive especially in high-frequency systems, are required. Besides, RAA can greatly improve system performance by configuring antenna elements with higher directionality, as each sULA only needs to be responsible for a portion of the total coverage angle. To demonstrate such advantages, in this paper, we first present the input-output model for RAA-based wireless communications, based on which the ray orientations of the RAA are designed. Furthermore, efficient algorithms for joint ray selection and beamforming are proposed for single-user and multi-user RAA-based wireless communications. Simulation results demonstrate the superior performance of RAA compared to HBF while significantly reducing hardware cost.

Paper Structure

This paper contains 6 sections, 15 equations, 5 figures, 1 table, 1 algorithm.

Table of Contents

  1. Introduction
  2. Proposed Ray antenna array
  3. RAA Orientation Design and Comparison with HBF
  4. Joint RAA Beamforming and Ray Selection
  5. Simulation Results
  6. Conclusion

Figures (5)

  • Figure 1: The proposed RAA consists of $MN$ cost-effective antenna elements, which are arranged into $N$ rays. Each ray corresponds to an $M$-element sULA, where all antenna elements are directly connected.
  • Figure 2: RAA-based wireless communications.
  • Figure 3: Beam patterns of the proposed RAA and HBF, considering (a) isotropic and (b) directional antenna element, where $M=8$ and $N=13$.
  • Figure 4: Maximum $\text{SNR}$ (dB) in (\ref{['SNR2']}) for the RAA and HBF.
  • Figure 5: The maximum $R_{\text{sum}}$ (bps/Hz) in (\ref{['channel model4']}) obtained via the exhaustive search and greedy scheme for the RAA and HBF.