ELIoT: enhancing LiFi for next-generation Internet of things

Abstract

Communication for the Internet of things (IoT) currently is predominantly narrowband and cannot always guarantee low latency and high reliability. Future IoT applications such as flexible manufacturing, augmented reality and self-driving vehicles rely on sophisticated real-time processing in the cloud to which mobile IoT devices are connected. High-capacity links that meet the requirements of the upcoming 6G systems cannot easily be provided by the current radio-based communication infrastructure. Light communication, which is also denoted as LiFi, offers huge amounts of spectrum, extra security and low-latency transmission free of interference even in dense reuse settings. We present the current state-of-the-art of LiFi systems and introduce new features needed for future IoT applications. We discuss results from a distributed multiple-input multiple-output topology with a fronthaul using plastic optical fibre. We evaluate seamless mobility between the light access points and also handovers to 5G, besides low-power transmission and integrated positioning. Future LiFi development, implementation and efforts towards standardization are addressed in the EU ELIoT project which is presented here.

Optical Wireless Communications: Illuminating the Path for Cooper's Law

“…The BBU handles physical layer functionalities, while the OFE is responsible for optical signal transmission and reception. Note that, since around 2020, some pilot deployments have been rolled out based on the ITU g.vlc standard and spatially distributed OFEs [205]. In the downlink chain of the network, the output of the BBU is connected to the OFE through a digital-to-analog converter (DAC).…”

“…within the network. This enables easier and more efficient implementation of joint processing of signals from different APs making it possible to leverage advanced physical layer techniques [205].…”

OFDM Bitloading in Distributed MIMO OWC Using Power-Constrained LEDs

“…For OWC, D-MIMO is considered as a key solution to provide stable coverage, as it can guarantee link operation even if one or more LoS links are blocked. To coordinate signal transmission through multiple LEDs, various schemes are commonly considered such as by performing repetition coding (RC), spatial modulation or spatial multiplexing (SMP) [29]. Also by simultaneously casting the same coded-OFDM via multiple outlets [29], possibly mitigating multi-path fades by coding and interleaving in the frequency domain as described in section 9.3 in [10].…”

“…In fact, the ITU-T G.9991 (a.k.a. G.vlc) standard [33], used in the market for OWC uses OFDM and has been shown to be extendable to D-MIMO [29], [34]. However, in general, the performance of OFDM with MIMO depends on whether accurate channel information is available in real time and can be estimated without excessive overhead.…”

“…Unlike RF, in OWC systems most of the signal energy is in the LoS path and multi-path plays much less pronounced role [11], [29]. Indoors, reflected paths mostly have a short excess delay, which is most often in the order of magnitude of the sampling time of the OFDM system.…”