Terahertz-Band Channel and Beam Split Estimation via Array Perturbation Model

Abstract

For the demonstration of ultra-wideband bandwidth and pencil-beamforming, the terahertz (THz)-band has been envisioned as one of the key enabling technologies for the sixth generation networks. However, the acquisition of the THz channel entails several unique challenges such as severe path loss and beam-split. Prior works usually employ ultra-massive arrays and additional hardware components comprised of time-delayers to compensate for these loses. In order to provide a cost-effective solution, this paper introduces a sparse-Bayesian-learning (SBL) technique for joint channel and beam-split estimation. Specifically, we first model the beam-split as an array perturbation inspired from array signal processing. Next, a low-complexity approach is developed by exploiting the line-of-sight-dominant feature of THz channel to reduce the computational complexity involved in the proposed SBL technique for channel estimation (SBCE). Additionally, based on federated-learning, we implement a model-free technique to the proposed model-based SBCE solution. Further to that, we examine the near-field considerations of THz channel, and introduce the range-dependent near-field beam-split. The theoretical performance bounds, i.e., Cramér-Rao lower bounds, are derived both for near- and far-field parameters, e.g., user directions, beam-split and ranges. Numerical simulations demonstrate that SBCE outperforms the existing approaches and exhibits lower hardware cost.

arXiv commentAccepted Paper in IEEE Open Journal of Communications Society

References in corpus (13)

• Federated Learning: Challenges, Methods, and Future Directions
• Spatially Sparse Precoding in Millimeter Wave MIMO Systems
• An Overview of Signal Processing Techniques for Millimeter Wave MIMO Systems
• Limited Feedback Hybrid Precoding for Multi-User Millimeter Wave Systems
• Frequency Selective Hybrid Precoding for Limited Feedback Millimeter Wave Systems
• Spatial- and Frequency-Wideband Effects in Millimeter-Wave Massive MIMO Systems
• Beam Squint and Channel Estimation for Wideband mmWave Massive MIMO-OFDM Systems
• Twenty-Five Years of Advances in Beamforming: From Convex and Nonconvex Optimization to Learning Techniques
• Hybrid Beamforming for Terahertz Multi-Carrier Systems over Frequency Selective Fading
• A Block Sparsity Based Estimator for mmWave Massive MIMO Channels with Beam Squint
• BSA-OMP: Beam-Split-Aware Orthogonal Matching Pursuit for THz Channel Estimation
• Terahertz-Band Integrated Sensing and Communications: Challenges and Opportunities
• Near-Field Wideband Beamforming for Extremely Large Antenna Arrays

Cited by in corpus (5)

• Near-Field Terahertz Communications: Model-Based and Model-Free Channel Estimation
• BSA-OMP: Beam-Split-Aware Orthogonal Matching Pursuit for THz Channel Estimation
• Spatial Path Index Modulation in mmWave/THz-Band Integrated Sensing and Communications
• A Unified Approach for Beam-Split Mitigation in Terahertz Wideband Hybrid Beamforming
• Toward Beamfocusing-Aided Near-Field Communications: Research Advances, Potential, and Challenges