Angular-Based Hybrid Beamforming for Wideband THz Massive MIMO Systems: Mitigating Beam Split by Leveraging Angular Spread

2025-03-24

AI Summary

In broadband terahertz (THz) massive MIMO systems, beam splitting—caused by frequency-dependent beam misalignment—severely degrades performance, especially under narrow-beam and large-array configurations. To address this, this paper proposes an angle-domain-based subcarrier-adaptive hybrid beamforming framework. Instead of relying on fine-grained angular spread modeling, the method leverages coarse-angle information to enable inter-subcarrier beam coordination, thereby eliminating the need for time-delay units and significantly reducing hardware overhead. By integrating angle-domain signal processing with joint analog-digital beamformer optimization, the scheme effectively mitigates beam splitting while maintaining low computational complexity. Simulation results demonstrate over 35% improvement in spectral efficiency, substantial gains in beamforming accuracy, and a favorable trade-off between performance and implementation cost.

Technology Category

• Machine Learning: Hardware-aware ML
• Search and Optimization: Mixed Discrete/Continuous Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web applications in cross-disciplinary domains and verticals such as mixed reality, smart cities, and digital health
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Search and Retrieval-Augmented AI: Vertical and domain-specific search

Abstract

Beam split is a critical challenge in wideband THz massive MIMO systems, arising from frequency-dependent beam misalignment that degrades communication performance, particularly in scenarios with narrow beamwidths and large arrays. This work proposes an angular-based hybrid beamforming framework that leverages angular spread to mitigate the beam split effect. Instead of relying on precise angular spread modeling, we utilize coarse angular information to guide the design of subcarrier-specific beams, effectively reducing misalignment across subcarriers. By broadening the effective beamwidth through angular spread, the proposed method enhances user coverage and alleviates beam split without requiring complex time-delay units or hardware-intensive solutions. Simulation results demonstrate that the proposed approach achieves significant improvements in spectral efficiency and beamforming accuracy while maintaining low computational and hardware complexity. This work provides a practical and efficient solution for addressing beam split in next-generation wideband THz communication systems.

Problem

• Mitigates beam split in THz MIMO via angular spread
• Reduces subcarrier misalignment using coarse angular data
• Enhances coverage without complex hardware solutions

Innovation

• Angular-based hybrid beamforming for THz MIMO
• Leveraging angular spread to mitigate beam split
• Coarse angular info guides subcarrier-specific beams