A number of inherently unipolar orthogonal frequency division multiplexing (OFDM) modulation schemes have been introduced recently in an attempt to improve the energy efficiency of OFDM-based intensity modulation and direct detection (IM/DD) systems.
This is our extended ECOC 2015 and invited Journal of Lightwave Technology (JLT) paper. The paper 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.
This our recently published paper on the downlink performance of optical attocell networks. 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.
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.
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.
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.