Latest Li-fi Research News

The latest Li-Fi Research and Development News from Professor Harald Haas.

DOI: 10.1109/JLT.2015.2510021

This is our extended ECOC 2015 and invited Journal of Lightwave Technology (JLT) paper. A pre-print can be downloaded from here.

LiFi provides a completely new layer of wireless connectivity within existing heterogeneous radio frequency (RF) wireless networks. LiFi supports multiuser access and enables roaming. It is, therefore, a truly mobile system. Multisuer access and mobility support in LiFi require unique building blocks as outlined in the figure below.  Techniques developed for RF systems cannot be applied direct as the signal propagation and information encoding techniques are different. However, the differences diminish as higher frequencies in RF are used such as mm wave bands. The paper also describes the first LiFi transmitter and receiver ASICs (application specific integrated circuits) developed at the University of Edinburgh as part of the UP-VLC project. These ASICs allow real-time data transmission of 1 Gbps as well as support multiple-input-multiple-output (MIMO) operation and wavelength division multiplexing (WDM). LiFi fulfils many key performance indicators (KPI) postulated for 5G systems.

LiFi building blocks

DOI: 10.1109/JLT.2015.2511015

This our recently published paper on the downlink performance of optical attocell networks. A pre-print of the paper can be downloaded here.

This work shows that optical attocell networks can improve the area data rate of radio frequency based femtocell networks by up to three orders of magnitude. In addition a comparison with future mm-wave based cellular networks is provided, and it is shown that the are data rate can be double the one achieved with future mm wave cellular networks. The optical attocell networks are assumed to exploit the existing lighting infrastructure.

Comparing optical attocell networks with mm-wave networks and femtocell networks[click to enlarge]

LiFi could transmit up to 100 Gbps and possibly higher, but this would require a change in lighting technology.

Recent news report that LiFi is 100 times faster than WiFi. The assumption was that the average WiFi speeds are 10 Mbps, and that LiFi can be as fast as 1 Gbps. It is important to highlight that 1 Gbps transmission speeds from an off-the-shelf commercial LED light bulb have not been demonstrated, yet. In this discussion, it is important to compare like-for-like.

Read the facts on Lifi in this article by Professor Harald Haas.

Professor Haas presentation slide: LiFi 'speed roadmap' based on lighting technologies

Light-Fidelity (LiFi) takes visible light communication (VLC) further by using light emitting diodes (LEDs) to realise fully networked wireless systems.

Our latest research on load balancing in hybrid WiFi/LiFi networks has shown an interesting result: There is a direct relationship between WiFi throughput and LiFi throughput. Specifically, as the LiFi throughput increases, so does the WiFi throughput, and vice versa.

WiFi / LiFi throughput

We have received the Jack Neubauer Memorial Award for our paper "Bit Error Probability of SM-MIMO Over Generalized Fading Channels",  as the Best System paper, published in the IEEE Transactions on Vehicular Technology in March 2012.

Jack Neubauer Memorial Award of IEEE Vehicular Technology Society, September 2015


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