LiFi: Making Fibre Wireless

Mohamed Sufyan Islim and Harald Haas

http://www.lifi.eng.ed.ac.uk/

@dlarah15

Wireless data demandGlobal Mobile Data Traffic

© 2010 mylerdude – Flickr. This work is licensed under Creative Commons Attribution 2.0 Generic.

© 2010 mylerdude – Flickr. This work is licensed under Creative Commons Attribution 2.0 Generic.

Path loss

𝐿 ∝ 𝑓2Friis equation:

Additional path loss

3 GHz 60 GHz: 26 dB !

The electromagnetic spectrum

What LiFi is NOT only

Why not use existing infrastructure?

LiFi for 5G and beyond

[1] Haas, H., “High-speed wireless networking using visible light, SPIE Newsroom, Online: http://spie.org/x93593.xml (invited)

[2] Haas, H., and Cheng Chen, “What is LiFi?”, ECOC 2015, 27 Sep. – 1 Oct. 2015 (invited)

[3] Haas, H., Wang, Y., Cheng Chen, and Yin, L., “What is LiFi?”, Journal of Lightwave Technology, vol. 3, iss. 8, April 2016 (invited)

[4] Tsonev, D.; Videv, S.; and Haas, H.; “Light fidelity (Li-Fi): towards all-optical networking,” Proc. SPIE 9007, Broadband Access Communication

Technologies VIII, 900702, 1 Feb. 2014

5

• Security

• Energy Efficiency

• Localization

• Data density

• Safety

LiFi: Competitive Advantages

Common Misconceptions

Is this a line-of-sight technology? What about flickering?

A: Let’s do an experiment.Will there be interference from sunlight?

Performance comparison Dark Room

Sunlight Irradiance

Sunlight + Blue Filter

S86

64

-50

K[1

9.6

mm

2]

Average SNR [dB] 17.57 12.42 16.64

SNR degradation compared to Dark Room 0% 29.33% 5.32%

Data rate @ BER< 3.8e-3 [Mbps] 416.44 313.35 396.71

Degradation of data rates compared to Dark Room.

0% 24.8% 4.7%

S86

64

-05

K[0

.19

mm

2]

Average SNR [dB] 18.58 16.42 17.36

SNR degradation compared to Dark Room 0% 11.6% 1.7%

Data rate @ BER< 3.8e-3 [Mbps] 1139.26 1015 1122.34

Degradation of data rates compared to Dark Room.

0% 10.9% 1.5%

Misconception: Interference from sunlightLa

rge

AP

DSm

all

AP

D

Misconception: There are no components

LED technology

Data rate / Gbps

RGB LEDPhosphor coated blue LED

GaN micro LED

0.1

1

10

100

RGB laser LEDs

Other common misconceptions...• Lights cannot be dimmed.

• This is for downlink only.

• Lights need to be on so this is inefficient.

Is it only for short distance?

1.1 Gbps @ 10 m

10 m1.1 Gbps

19

Towards 100 Gbps

1 m2

3 m

Data

Rate

[G

b/

s]

Averag

eB

ER

Req

uir

ed

D

evic

es

per 1

m2

Co

verag

e

Ilu

min

ati

on

[lx

]

14 6.07E-4 89 x 3 844

100 2.04E-3 9 x 36 971

3.5 2.33E-3 3 21

http://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/laser-

lifi-could-blast-100-gigabits-per-second

Tsonev, et al, Optics Express, 2015

Transmitter and receiver ASICsTransmitter LiFi MIMO ASICReceiver LiFi MIMO ASIC

Jalajakumari, A.V.N.; Tsonev, D.; Cameron, K.; Haas, H.; Henderson, R., "An energy efficient high-speed digital LED driver for visible light communications," ICC 2015, doi: 10.1109/ICC.2015.7249125

16 Channel integrated transmitter ASIC

Light as a Service

Conclusion

Generations ParadigmShifts

Service pull Impact

1G 2G Analogue to digital

Mobile telephony Revolution

2G 3GSmall cell concept

Mobile Internet Evolution3G 4G

4G 5G RF to Light? LaaS and Internet of Things?

Revolution?