Orbital-Angular-Momentum Multiplexing Optical Wireless Communications With Adaptive Modes Adjustment in Internet-of-Things Networks

Internet of Things (IoT) involves trillions of devices to collect information data and exchange date one another, which could congest the IoT networks. Orbital-angular-momentum (OAM) multiplexing optical wireless communications (OWCs) enable to provide ultralarge capacity, high-speed, low-latency, low-energy consumption, secure, and reliable communications, thus being one of the most promising wireless access techniques for the deployment of IoT networks. However, the imperfect alignment of free-space optics system and air channel conditions pose formidable challenge to the OWC. Crosstalk among the parallel OAM mode channels will be induced. Herein, we present an adaptive modes adjustment scheme to mitigate the deleterious impacts. The numerical results reveal that the crosstalk can be suppressed strikingly by use of the proposed scheme.