See and Beam: Leveraging LiDAR Sensing and Specular Surfaces for Indoor mmWave Connectivity

TL;DR

This paper introduces See and Beam, a low-cost framework that uses LiDAR sensing and passive specular reflectors to improve indoor mmWave connectivity, especially in non-line-of-sight conditions, by mapping environments and guiding beam steering.

Contribution

It presents a novel integration of LiDAR sensing with passive reflectors to enhance mmWave communication robustness in indoor environments, demonstrating practical effectiveness.

Findings

LiDAR-mmWave co-reflective surfaces enable environment mapping and user localization.

Beam steering guided by LiDAR improves signal strength by over 20 dB in NLoS regions.

Performance comparable to exhaustive beam search using LiDAR-derived angles.

Abstract

Millimeter-wave (mmWave) communication enables multi-gigabit-per-second data rates but is highly susceptible to path loss and blockage, especially indoors. Many indoor settings, however, include naturally occurring specular surfaces such as glass, glossy metal panels, and signage, that reflect both light and mmWave signals. Exploiting this dual reflectivity, we propose See and Beam, a low-cost framework that combines LiDAR sensing with passive specular reflectors to enhance mmWave connectivity under non-line-of-sight (NLoS) conditions. In this paper, as a proof of concept, we deploy three types of reflectors, glossy, smooth, and matte (non-specular), to evaluate joint LiDAR/mmWave reflection in an indoor scenario. We demonstrate that using LiDAR-mmWave co-reflective surfaces enables a co-located LiDAR sensor to map the NLoS environment, localize NLoS users, and identify viable communication reflection points. Experimental results at 60 GHz show that LiDAR-guided beam steering with co-reflective surfaces improves the minimum received signal strength by over 20 dB in deep NLoS regions. Moreover, LiDAR-derived angle-of-departure steering achieves performance comparable to exhaustive NLoS beam search. This low cost, and scalable framework serves as an effective alternative to configurable reflecting surfaces and enables robust mmWave connectivity in future 6G and beyond networks.