50 Gbps Mobile Optical Wireless Communication Enabled by Lithium-Niobate-Based Beam Steering

This paper proposes a comprehensive beam tracking and alignment solution for mobile optical wireless communication (OWC) using a low-cost lithium niobate (LN) waveguide-based beam-steering device. The system achieves a 21.22$^{\circ }$ maximum scanning angle and a 1.376 $\mu$s fast response time, with a dynamic response bandwidth reaching the MHz level. To mitigate photodiode bandwidth limitations, the system employs orthogonal frequency division multiplexing (OFDM) with adaptive bit and power loading. For the first time, a full-process beam management algorithm is developed for the proposed device, comprising sector scanning, adjacent-beam tracking, and Kalman filter (KF)-based noise correction. Based on this algorithm, real-time 50Gbps communication in motion is demonstrated over a 1-meter distance, with potential for future range extension. Utilizing a commercial low-cost beam-steering device box, the system supports stable OWC tracking at up to 46.3$^{\circ }$/s, as verified through detailed time-overhead analysis. A novel mobility communication efficiency (MCE) metric is proposed to evaluate the integration performance of stable tracking and real-time communication, offering systematic guidance for future optimization. This work combines the cost-effective beam-steering device, adaptive modulation, and robust tracking to enable mobility in 6G-oriented OWC.