Wireless Communication with Flexible Reflector: Joint Placement and Rotation Optimization for Coverage Enhancement

2024-12-25

AI Summary

Signal coverage deficiency in wireless communications remains a critical challenge, particularly in non-line-of-sight (NLoS) environments. Method: This paper proposes a tunable directional flexible reflector (FR) architecture, which jointly optimizes the 3D spatial positions and rotation angles of multiple passive metallic reflectors to maximize the minimum received power over a target region. We introduce the FR concept for the first time and derive closed-form optimal placement solutions for both electrically large and small reflectors. A unified optimization framework is developed, integrating geometric channel modeling, specular reflection principles, and stepwise iterative non-convex optimization for single- and multi-reflector configurations. Results: Simulation results across diverse realistic scenarios demonstrate that the proposed FR scheme significantly outperforms conventional fixed reflectors and other baselines in terms of received power gain—achieving substantial coverage enhancement with zero energy consumption. These results validate both the feasibility and superiority of the FR architecture.

Technology Category

• Search and Optimization: Non-convex Optimization
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Intelligent Robots: Learning & Optimization for ROB

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Security and Privacy: Large-scale security measurements

Abstract

Passive metal reflectors for communication enhancement have appealing advantages such as ultra low cost, zero energy expenditure, maintenance-free operation, long life span, and full compatibility with legacy wireless systems. To unleash the full potential of passive reflectors for wireless communications, this paper proposes a new passive reflector architecture, termed flexible reflector (FR), for enabling the flexible adjustment of beamforming direction via the FR placement and rotation optimization. We consider the multi-FR aided area coverage enhancement and aim to maximize the minimum expected receive power over all locations within the target coverage area, by jointly optimizing the placement positions and rotation angles of multiple FRs. To gain useful insights, the special case of movable reflector (MR) with fixed rotation is first studied to maximize the expected receive power at a target location, where the optimal single-MR placement positions for electrically large and small reflectors are derived in closed-form, respectively. It is shown that the reflector should be placed at the specular reflection point for electrically large reflector. While for area coverage enhancement, the optimal placement is obtained for the single-MR case and a sequential placement algorithm is proposed for the multi-MR case. Moreover, for the general case of FR, joint placement and rotation design is considered for the single-/multi-FR aided coverage enhancement, respectively. Numerical results are presented which demonstrate significant performance gains of FRs over various benchmark schemes under different practical setups in terms of receive power enhancement.

Problem

• Wireless Signal Optimization
• Flexible Reflector Placement
• Multi-location Communication Enhancement

Innovation

• Flexible Reflector (FR)
• Optimal Placement Strategy
• Signal Enhancement