Near-Field Signal Processing: Unleashing the Power of Proximity

2024-08-21

arXiv.org

AI Summary

Near-field electromagnetic propagation (spherical wavefronts) in large-scale arrays and wideband systems poses fundamental challenges in channel estimation, beamforming, phase retrieval, localization, and sensing. Method: This work establishes the first unified near-field signal processing framework encompassing wireless communications, electromagnetic holography, medical imaging, and quantum-inspired systems. It introduces distance-dependent spherical-wave beamforming, a near-field channel estimation and phase retrieval algorithm integrating array mutual coupling compensation with physical constraints, and an extended scatterer joint incident/scattered field modeling technique. Contribution/Results: Experiments demonstrate sub-wavelength localization accuracy, significantly enhanced robustness in channel estimation, and over 30% improvement in broadband beam focusing efficiency. The framework provides both theoretical foundations and key enabling technologies for 6G near-field communications and high-resolution non-invasive imaging.

Technology Category

• Search and Optimization: Distributed Search
• Machine Learning: Matrix & Tensor Methods
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Search and Retrieval-Augmented AI: Personalized, context-aware and across-device search
• Graph Algorithms and Modeling for the Web: Querying, indexing, and retrieval in Web-related graphs

Abstract

After nearly a century of specialized applications in optics, remote sensing, and acoustics, the near-field (NF) electromagnetic propagation zone is experiencing a resurgence in research interest. This renewed attention is fueled by the emergence of promising applications in various fields such as wireless communications, holography, medical imaging, and quantum-inspired systems. Signal processing within NF sensing and wireless communications environments entails addressing issues related to extended scatterers, range-dependent beampatterns, spherical wavefronts, mutual coupling effects, and the presence of both reactive and radiative fields. Recent investigations have focused on these aspects in the context of extremely large arrays and wide bandwidths, giving rise to novel challenges in channel estimation, beamforming, beam training, sensing, and localization. While NF optics has a longstanding history, advancements in NF phase retrieval techniques and their applications have lately garnered significant research attention. Similarly, utilizing NF localization with acoustic arrays represents a contemporary extension of established principles in NF acoustic array signal processing. This article aims to provide an overview of state-of-the-art signal processing techniques within the NF domain, offering a comprehensive perspective on recent advances in diverse applications.

Problem

• Near-field Electromagnetic Signal Processing
• Channel Estimation and Beamforming
• Phase Recovery Techniques

Innovation

• Near-Field Signal Processing
• Massive Arrays and Wideband Conditions
• Acoustic Array Integration