Ultra-Low-Cost Hybrid Beamforming A New Static Connection Architecture with Sparse Phase-Shifter Sharing

Jul 16, 2026

Hybrid beamforming enables high-frequency multi-antenna wireless links, yet analog phase-shifter (PS) hardware cost and network complexity limit practical deployment. A static-connection sub-connected architecture is proposed that uses sparse PSs: multiple antennas in a sub-array share common PS hardware through a fixed, optimized PS-to-antenna connection matrix. Dynamic beam control remains via adaptive PS phase shifts plus digital precoding. For a single-RF-chain case, the design becomes an antenna-grouping problem with analytical properties and an efficient algorithm. For multi-RF-chain, a QoS–majorization-minimization algorithm solves the mixed discrete-continuous optimization. Results show 37.5% and 62.5% PS-count reductions while avoiding deep-null and grating-lobe degradation.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages13

Reading Time33 min

Abstract

Introduction

Background: limits of fully connected hybrid beamforming

Motivation: PS-count bottleneck in sub-connected architectures

Proposed static sparse PS-sharing architecture

Connection matrix and dynamic control mechanism

Single-RF-chain antenna-grouping formulation

Multi-RF-chain QoS-MM optimization

Ultra-Low-Cost Hybrid Beamforming: A New StaticConnection Architecture with Sparse Phase-Shifter Sharing Honghao Wang, Qingqing Wu, Yifei Wu, Yuxuan Chen, Wen Chen, and Derrick Wing Kwan Ng arXiv :2607 .02393v 1 [ cs .IT] 2 Jul 2026 Abstract—Hybrid beamforming is a promising solution for high-frequency multi-antenna wireless systems, but its practical implementation remains significantly constrained by the hardware cost and complexity of analog phase-shifter (PS) networks. Although sub-connected architectures significantly simplify the analog network, their conventional realization still requires a dedicated PS for each antenna, which leads to considerable layout area, wiring complexity, calibration efforts, and control overhead. To effectively address this issue, this paper proposes a novel staticconnection architecture with sparse PSs for ultra-low-cost subconnected hybrid beamforming, where multiple antennas within each sub-array can share a common PS through an optimized yet fixed PS-to-antenna connection matrix. The proposed architecture preserves static hardware connections while enabling dynamic beam control via adaptive PS phase-shift adjustments and digital precoding. For the single-radio-frequency (RF)-chain scenario, the sparse-PS connection design is transformed into an antenna-grouping problem, for which structural properties are characterized analytically and an efficient algorithm is developed. For the multi-RF-chain scenario, we develop a competent qualityof-service (QoS)-majorization-minimization (MM) algorithm to handle the mixed discrete-continuous joint optimization problem. Numerical results demonstrate that the proposed architecture substantially reduces the PS count while preserving most of the beamforming capability provided by the traditional full-PS sub-connected architecture. In particular, the proposed design achieves PS-count reductions of 37.5% and 62.5% in single-RFchain and multi-RF-chain systems, respectively, while effectively avoiding deep-null and grating-lobe degradations associated with rigid deterministic connection schemes. These results provide engineering insights into static sparse-PS sharing: the key to hardware-efficient hybrid beamforming is not merely reducing the PS count, but also preserving the essential analog-domain degrees of freedom through optimized PS connection topologies. I. INTRODUCTION Future high-frequency wireless systems rely on directional transmission provided by large-scale antenna to compensate for severe propagation loss and to achieve communication services [1]–[3] . In this context, fully digital precoding becomes impractical since connecting each antenna directly to a dedicated radio frequency (RF)-chain, incurs excessive hardware costs, power consumption, and implementation burden [4]–[6] . As a remedy, hybrid beamforming has been proposed to address this challenge by exploiting fewer RFchains combined with a high-dimensional analog phase-shifter (PS) network, enabling most spatial processing to be performed H. Wang, Q. Wu, and W. Chen are with the School of Information Science and Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China (e-mail: [hhwang@sjtu.edu.cn](hhwang@sjtu.edu.cn); [qingqingwu@sjtu.edu.cn](qingqingwu@sjtu.edu.cn); [wenchen@sjtu.edu.cn](wenchen@sjtu.edu.cn)). Y. Wu is with the Institute for Digital Communications, Friedrich-Alexander-Universitt Erlangen-N¨urnberg (FAU), Germany (e-mail: [yifei.wu@fau.de](yifei.wu@fau.de)). Y. Chen is with the Huawei Device Company Ltd., Shenzhen 518129, China (e-mail: [chenyuxuan56@huawei.com](chenyuxuan56@huawei.com)). D. W. K. Ng is with the School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia ([e-mail: w.k.ng@unsw.edu.au](e-mail: w.k.ng@unsw.edu.au)). (Corresponding author: Qingqing Wu) . in the analog domain, while a low-dimensional digital precoder handles data multiplexing and interference manag

FAQs

What problem does the proposed architecture address in sub-connected hybrid beamforming?

The architecture targets the hardware bottleneck caused by requiring a dedicated PS for each antenna, which increases layout area, wiring density, calibration effort, and control overhead.

How does the static sparse PS-sharing design enable dynamic beam control with fixed connections?

It preserves static hardware PS-to-antenna connections via an optimized fixed connection matrix, while enabling beam steering through adaptive PS phase adjustments and digital precoding.

How are the optimization problems handled for single-RF-chain and multi-RF-chain scenarios?

For single-RF-chain, the sparse-PS connection design is transformed into an antenna-grouping problem with characterized structural properties and an efficient algorithm. For multi-RF-chain, a QoS–majorization-minimization method addresses the mixed discrete-continuous joint optimization.

Jul 16, 2026

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