Radio Access Selection for Mobile Robots in Hybrid Li-Fi and mmWave Networks

The emerging beyond fifth-generation (B5G) and sixth-generation (6G) wireless networks utilizing ultra-high bands are considered key enablers in supporting diversified applications for industrial mobile robots (MRs). Hybrid light fidelity (Li-Fi) and millimeter wave (mmWave) networks can provide high-speed data transmission and enhanced coverage for indoor mobile robot communications. The hybrid network scenario investigated in this paper relates to MRs that autonomously roam on an industrial floor and perform a variety of tasks at different workstations along planned trajectories. The selection of wireless access for robot transmissions at workstations remains a challenge due to co-channel interference that might deteriorate overall network performance. To resolve this issue, a novel mmWave/Li-Fi access mode selection optimization problem is proposed via an integer programming formulation where the achieved data rate is considered jointly by considering both vertical and horizontal handovers. A wide set of numerical investigations reveal that the proposed optimal access mode selection (OAMS) can improve the overall network throughput by 14 % and 46 % compared with mmWave and Li-Fi communication access at workstations, respectively, while achieving a higher grade of individual transmission fairness and robustness.