mmProjector: Low-cost mmWave Reflector for Mobile Industrial Robot Communication

Millimeter-wave (mmWave) technology offers significant potential for high-bandwidth, low-latency communication industrial applications. However, mmWave faces several challenges, such as limited range, susceptibility to blockage, and slow beam alignment. For this, mmWave access points (APs) are often deployed at high densities, which leads to increased costs. In this paper, we introduce mmProjector, the first cost-effective reflector, which is non-reconfigurable with a static structure but can serve mobile industrial robots. The key idea is to reshape the reflected waves only along the robots’ movement trajectories using mmProjector and make the phase of reflected wave constructively added along the trajectories, improving reflection gain with limited incident waves. To achieve this, we develop an analytical model grounded in electromagnetic theory and propose sub-optimal algorithms for the deployment and shape design of reflectors. We prototype mmProjector and deploy it in a real-world airplane assembly factory. Experiments demonstrate that mmProjector operates effectively at 60 GHz, delivering up to 1.8 Gbps of bandwidth in non-line-of-sight (NLOS) scenarios, while achieving up to 75% reduction in costs.