Design and implementation of an uplink connection for a light-based IoT node

Abstract. In the wake of soaring demand for shrinking radio frequency (RF) spectrum, light-fidelity (LiFi) has been heralded as a solution to accommodate resources for future communication networks. Infrared (IR) and visible light communication (VLC) are meant to be used within LiFi because of numerous advantages. By combining the paradigm of internet of things (IoT) along with LiFi, light-based IoT (LIoT) emerges as a potential enabler of future 6G networks. With tremendous number of interconnected devices, LIoT nodes need to be able to receive and transmit data while being energy autonomous. One of the most promising clean energy sources comes from both natural and artificial light. In addition to providing illumination and energy, light can also be utilized as a robust information carrier. In order to provide bidirectional connectivity to LIoT node, both downlink and uplink have to be taken into consideration. Whereas downlink relies on visible light as a carrier, uplink approach can be engineered freely within specific requirements. With this in mind, this master’s thesis explores possible solutions for providing uplink connectivity. After analysis of possible solutions, the LIoT proof-of-concept was designed, implemented and validated. By incorporating printed solar cell, dedicated energy harvesting unit, power-optimised microcontroller unit (MCU) and light intensity sensor the LIoT node is able to autonomously transmit data using IR

Introduction to indoor networking concepts and challenges in LiFi

LiFi is networked, bidirectional wireless communication with light. It is used to connect fixed and mobile devices at very high data rates by harnessing the visible light and infrared spectrum. Combined, these spectral resources are 2600 times larger than the entire radio frequency (RF) spectrum. This paper provides the motivation behind why LiFi is a very timely technology, especially for 6th generation (6G) cellular communications. It discusses and reviews essential networking technologies, such as interference mitigation and hybrid LiFi/Wi-Fi networking topologies. We also consider the seamless integration of LiFi into existing wireless networks to form heterogeneous networks across the optical and RF domains and discuss implications and solutions in terms of load balancing. Finally, we provide the results of a real-world hybrid LiFi/Wi-Fi network deployment in a software defined networking testbed. In addition, results from a LiFi deployment in a school classroom are provided, which show that Wi-Fi network performance can be improved significantly by offloading traffic to the LiFi

Invoking Deep Learning for Joint Estimation of Indoor LiFi User Position and Orientation

Light-fidelity (LiFi) is a fully-networked bidirectional optical wireless communication (OWC) that is considered a promising solution for high-speed indoor connectivity. Unlike in conventional radio frequency wireless systems, the OWC channel is not isotropic, meaning that the device orientation affects the channel gain significantly. However, due to the lack of proper channel models for LiFi systems, many studies have assumed that the receiver is vertically upward and randomly located within the coverage area, which is not a realistic assumption from a practical point of view. In this paper, novel realistic and measurement-based channel models for indoor LiFi systems are proposed. Precisely, the statistics of the channel gain are derived for the case of randomly oriented stationary and mobile LiFi receivers. For stationary users, two channel models are proposed, namely, the modified truncated Laplace (MTL) model and the modified Beta (MB) model. For LiFi users, two channel models are proposed, namely, the sum of modified truncated Gaussian (SMTG) model and the sum of modified Beta (SMB) model. Based on the derived models, the impact of random orientation and spatial distribution of LiFi users is investigated, where we show that the aforementioned factors can strongly affect the channel gain and system performance

Powering the Internet of Things Through Light Communication

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Novel solutions are required to connect billions of devices to the network as envisioned by the IoT. In this article we propose to use LiFi, which is based on off-the-shelf LEDs, as an enabler for the IoT in indoor environments. We present LiFi4IoT, a system which, in addition to communication, provides three main services that the radio frequency (RF) IoT networks struggle to offer: precise device positioning; the possibility of delivering power, since energy can be harvested from light; and inherent security due to the propagation properties of visible light. We analyze the application space of IoT in indoor scenarios, and propose a LiFi4IoT access point (AP) that communicates simultaneously with IoT devices featuring different types of detectors, such as CMOS camera sensors, PDs, and solar cells. Based on the capabilities of these technologies, we define three types of energy self-sufficient IoT "motes" and analyze their feasibility. Finally, we identify the main research directions to enable the LiFi4IoT vision and provide preliminary results for several of these.Peer ReviewedPostprint (author's final draft

Wireless infrared-based LiFi uplink transmission with link blockage and random device orientation

Light-fidelity (LiFi) is recognised as a promising technology for next generation wireless access networks. However, limited research efforts have been spent on the uplink (UL) transmission system in LiFi networks. In this article, a wireless infrared (IR)-based LiFi UL system is investigated. In particular, we focus on the performance of a single static user under the influence of random device orientation and link blockage. Simulations and mathematical analysis have been used to evaluate the UL system performance. The analytical expressions for the UL optical wireless channel and signal-to-noise ratio (SNR) statistics under the effects of random device orientation and link blockage are derived. The results show that the effects of random orientation and link blockage may lead to a decrease in coverage probability by 10% - 40% with various SNR thresholds