Circular Holographic MIMO Beamforming for Integrated Data and Energy Multicast Systems

2025-07-07

AI Summary

This paper addresses the integrated data and energy multicasting (IDEM) problem in circular holographic MIMO (H-MIMO) systems, aiming to maximize the minimum achievable rate among data users (DUs) subject to minimum harvested energy constraints for energy users (EUs). A low-complexity near-field beamforming scheme is proposed. First, a closed-form expression for three-dimensional near-field spatial resolution is derived, revealing the asymptotic spatial orthogonality of circular arrays in the near-field regime. Leveraging this insight, an asymptotically optimal digital beamformer is designed and jointly optimized with three analog beam-steering modes and a power-scaling strategy. An alternating optimization algorithm is developed, balancing performance and implementation complexity. Simulation results demonstrate that the proposed scheme significantly outperforms baseline methods—achieving higher minimum DU rates while satisfying EU energy requirements—and incurs extremely low computational complexity.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Mixture of Experts (MoE)

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Web Mining and Content Analysis: Web data generation and simulation

Abstract

Thanks to the application of metamaterials, holographic multiple-input multiple-output (H-MIMO) is expected to achieve a higher spatial diversity gain with lower hardware complexity. With the aid of a circular antenna arrangement of H-MIMO, integrated data and energy multicast (IDEM) can fully exploit the near-field channel to realize wider range of energy focusing and higher achievable rate. In this paper, we derive the closed-form near-field resolution function in 3D space and show the asymptotic spatial orthogonality of near-field channel for circular antenna array. We then investigate the beamforming designs for IDEM systems, where the minimum rate of data users (DUs) are maximized while guaranteeing the energy harvesting requirements for energy users (EUs). Specifically, the asymptotically optimal fully-digital beamformer is first obtained based on the spatial orthogonality. Then, the alternating optimization is adopted for the H-MIMO beamforming, where the digital beamformer is obtained in closed form and the analog beamformers of three different control modes are then obtained, respectively. Scaling schemes are also investigated to further improve the IDEM performance. Numerical results verify the correctness of the resolution function and asymptotic orthogonality. Moreover, the proposed beamforming schemes with very low complexity outperform benchmark schemes.

Problem

• Designing beamforming for integrated data and energy multicast systems
• Maximizing data rate while meeting energy harvesting requirements
• Exploring low-complexity H-MIMO beamforming with circular antenna arrays

Innovation

• Circular H-MIMO for near-field energy focusing
• Closed-form 3D near-field resolution function
• Low-complexity alternating optimization beamforming