Impact of Pointing Errors and Correlated Wall Blockages on Practical Grid-based Indoor Terahertz Communication Systems

2026-02-24

AI Summary

This study addresses the degradation of coverage performance in indoor terahertz (THz) communication systems caused by beam misalignment, human blockage, and spatial correlation of wall-induced blockages among access points (APs). The authors develop an analytically tractable three-dimensional system model that, for the first time, jointly characterizes the impact of spatially correlated wall blockages and residual beam misalignment on THz networks deployed in square and hexagonal grid patterns. By integrating stochastic geometry, three-dimensional ray-tracing approximations, beamforming analysis, and Monte Carlo simulations, the work uncovers a non-monotonic relationship between antenna array size and beam training overhead. Results demonstrate that hexagonal deployment significantly outperforms square deployment, spatial correlation of wall blockages severely degrades coverage probability, and system performance deteriorates markedly when users are distant from APs or suffer from beam misalignment. Furthermore, beam training efficiency is jointly constrained by antenna configuration and beamwidth.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Applications
• Cognitive Modeling & Cognitive Systems: Applications

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

Terahertz (THz) communications has emerged as a promising technology for future wireless systems due to its potential to support extremely high data rates. However, severe path loss, blockage effects, and sensitivity to beam misalignment pose major challenges to reliable indoor THz communications. In this paper, we investigate the coverage probability of downlink transmission in a three-dimensional (3D) indoor THz communication system under structured access point (AP) deployments, with a focus on square and hexagonal grid topologies. A tractable analytical framework is developed to jointly account for human blockages, correlated wall blockages across APs, beam training, and residual pointing error. Numerical results demonstrate that wall blockage correlation significantly reduces the association and coverage probabilities, and its impact cannot be neglected in system performance analysis. Compared with square grid AP deployments, hexagonal grids consistently achieve higher coverage by mitigating correlated wall blockage effects and reducing the distances between user equipments (UEs) and their associated APs. Furthermore, coverage performance is shown to strongly depend on the UE location, with noticeable degradation as the UE moves away from its nearest AP. Residual pointing error is found to introduce substantial coverage loss, especially for longer links. In addition, beam training analysis reveals a non-monotonic relationship between antenna array size and training overhead, highlighting an inherent tradeoff among antenna configuration, beamwidth selection, and beam training efficiency. These findings provide useful insights into the design and deployment of practical indoor THz communication systems.

Problem

• pointing errors
• correlated wall blockages
• terahertz communications
• indoor coverage
• grid-based deployment

Innovation

• terahertz communications
• correlated blockages
• pointing error
• grid-based deployment
• beam training