OPTICAL WIRELESS COMMUNICATIONS

“From the space to the chip”

OQCG Short Seminar SeriesMarch 2014

My Snapshot

PhD (2009) @ UPV - “Wireless comms integration on Optical networks (RoF, UWB, WiMAX, WDM, PolMux, …)”

• Previous Research topics about OWC

– Atmospheric turbulence effects on outdoor OWC

– Hybrid systems FSO/RF

– OWC for intelligent transport system

– Others : LTE over fiber, Indoor VLC systems (TV/Internet streaming) Indoor POF+VLC

• Common topics:

– Optical transceivers

– New efficient modulation schemes

– Optical transmission

March 2014 - OQCG Seminars

Optical Wireless Communications

• Ancient as the human kind

– beacon fires, smoke, ship flags or semaphore telegraph

– Photophone 1880 A.G.Bell

• Laser revolution 1962 MIT Lincoln Labs OWC GaAs light source over 30 miles for TV transmission

– Beam divergence problems, atmospheric effects, the fibre appears at 70’s to solve those problems

– OWC relegated to satellite interlinks, IrDA, some military applications.

March 2014 - OQCG Seminars

Optical Wireless Communications

• Advantages: Low Cost, license free, high BW access solution

– Light sources : LASER – LED – OLED

• Problems: atmospheric losses, turbulence, and pointing errors

• Many applications

– Optical angular moments for Quantum Cryptography

– Satellite optical networks

– Wearable interaction

– Indoor low-cost communications

– Enterprise/campus connectivity

– Video surveillance and monitoring

– Backhaul for cellular systems

– Broadcasting

– Redundant link and disaster recovery

March 2014 - OQCG Seminars

Ultra-long and long range OWC

• Sports events (F1)

• Campus, MAN networks(Cablefree, LightPointe ...)

• Security and defence communications (CASSIDIAN, EADS, ...)

March 2014 - OQCG Seminars

Air-to-Ground FSO

• Air-to-ground FSO quantum-key distribution communication (Nature Photonics 7, 382–386 (2013))

(Photos: DLR)

Speed of 290 km/h at a distance of 20 km or 4 mrad/s

March 2014 - OQCG Seminars

Space-ground FSO

• Laser Communications Relay Demonstration LCRD

• High bandwidth geo-sync to ground optical link– Downlink: 1.2 Gbps– Uplink: 1.2 Gbps– LCRD Payload Flight in 2017 on

Loral Commercial Satellite

• Bidirectional low Earth orbit-to-ground optical link– 2 Mb/s UL and 50 Mb/s DL

M.W. Wright et al. , 26 September 2011, SPIE Newsroom.

(Photos: NASA and SPIE)

March 2014 - OQCG Seminars

FSO networks

• Intra-satellite

• Campus networks

• FSO link needs line of sight (LOS)

• Link Obstacles??

– Buildings, fog, turbulence...

– No connection!

• A mesh topology as a solution??

(Photos: ESA)

March 2014 - OQCG Seminars

OWC comms and adverse channel effects

Mitigating Turbulence Effect

• Spatial Diversity Solutions

• Relay-Assisted FSO Networks

• Hybrid RF/FSO Links

OWC impairments are derived from the channel variations

• Adverse Channel Effects

– Background Radiations

– Pointing Errors

– Atmospheric Loss

– Atmospheric Turbulence

March 2014 - OQCG Seminars

Medium range OWC

• IR indoor comms

– Irda extended (Giga-IR)

• Vehicle-2-Vehicle comms

– Volvo Intelligent road concept

• Visible Light Comms - VLC

– Li-Fi, internet

– LED shopping assistant

March 2014 - OQCG Seminars

LED and VLC

• RGB • Blue Chip + Phosphor

- Well-known technology- Limited use due to difficulties in

RGB balancing- Phasing out in lighting industry- Wide modulation bandwidth

- Popular for today general lighting industry

- Standardised for illumination and communications

- Limited modulation bandwidth

White Light emission

March 2014 - OQCG Seminars

LED and VLC

• LED -> PN junction -> Small transit time

• Modulation BW from 3 MHz to 20 MHz

• Enough for communications?– Equalisation techniques

• Up to 40 Mb/S @ 400 Lux, 2m range [1] using multi-tone equalisation at transmitter

– Complex modulation• PAM

• OFDM OMEGA FP7 project (2011) (Siemens/HHI) has demonstrated 84 Mbps OFDM/QAM – over 3m [2]

– MIMO as a diversity technique• 4x4 50 Mb/s [3]

– Gigabit VLC = EQ + OFDM + MIMO [4]

[1] H. Le-Minh et al., "High-Speed Visible Light Communications Using Multiple-Resonant Equalization", IEEE PTL 15 (20), Jul. 2008[2] http://www.youtube.com/watch?v=AqdARFZd_78[3] A. Burton et al. “Experimental Demonstration of 50 Mb/s Visible Light Communications using 4×4 MIMO,” IEEE PTL, March 2014[4] G. Cossu et al. “2.1 Gbit/s Visible Optical Wireless Transmission”, ECOC 2012 , P4.16

March 2014 - OQCG Seminars

LED and VLC

• Mobility

– NLOS must work

– Channel reflections

– Smart receiver• Diffuse receiver: direct and

reflected path

• Multiple receivers: best signal

• LOS vs NLOS: GAIN 20 dB

• Light dimmingKey effects

– The SNR is no longer the advantage

– Signal could be discontinued

Main dimming technologies

– Driving current reduction lower PTx and SNR

– Pulse width modulation (PWM) Signal disruption

TransmitterReceiverAWGRTO

Spectrum

analyzer

0% 50% 75% 100%PWM MSR

30 Mb/s

50 Mb/s

70 Mb/sBy A. Burton et al. To be published in 2014

March 2014 - OQCG Seminars

LED VLC integration

• Video streaming over LED link

• 10 Mb/s

• Nov. 2013

March 2014 - OQCG Seminars

LED - OLED

• Solid-state light emitting diode (LED)

– Compact, cheap, powerful

– 50% light

– More than 50,000 hours lifespan

• Organic light emitting diode (OLED)

– Flexible and bendable panel

– Extensively used in high-end display products,

– HDTV and Smartphone

March 2014 - OQCG Seminars

OLED Devices

March 2014 - OQCG Seminars

OLED Current State-of-Art

• Efficiency– 100% internal quantum efficiency (Fraunhofer IPMS – COMEDD, 2012)

– Brightness 2.000 cd/m², 5mm thickness (Verbatim Velve, 2012)

– 120 lumen (~table lamp) (Philip Lumiblade GL350, 2012)

– 80 lumen/watt with 20.000 hours of lifetime (LG, 2012)

March 2014 - OQCG Seminars

OLED Current State-of-Art

• Applications– Dominant in high end Smartphone display products: Super-AMOLED,

(Samsung Galaxy S3 phone, 2012)

– 55 inch OLED HDTV (Samsung Electronics, 2012)

– 6 inch E-paper on plastic (XGA, 14 gram, 0.7mm thickness), (LG, 2012)

– Solar OLED car (BASF, 2012)

– Flexible AMOLED display (Samsung patent, 2012)

– None of the commercial applications is for communications!

March 2014 - OQCG Seminars

Electrical Characterisation

• For lighting– Large panel better for illumination

larger capacitor value

• For communicationsLarger capacitor value slow response

Rp - electrode contact resistanceRd - diode resistanceC - diode capacitance

March 2014 - OQCG Seminars

OLED – Techniques

Aim: High-speed OLED VLC system (Mbit/s over kHz bandwidth)

• Analogue Equalisation

• Decision Feedback Equalisation

• OFDM / QAM

• ANN

– P. A. Haigh, Z. Ghassemlooy, and I. Papakonstantinou, "1.4 Mb/s White Organic LED Transmission System using Discrete Multi-tone Modulation," IEEE Photonics Technology Letters, vol. PP, pp. 1-1, 2013

– Paul Anthony Haigh, Francesco Bausi, Zabih Ghassemlooy, Ioannis Papakonstantinou, Hoa Le Minh, Charlotte Fléchon, Franco Cacialli, "Visible light communications: real time 10 Mb/s link with a low bandwidth polymer light-emitting diode," Opt. Express 22, 2830-2838 (2014);

.

March 2014 - OQCG Seminars

Short and ultra-short range OWC

• Wireless body area networks

– Wearables :

– Toys, dresses and LED interactions

• Disney research [1]

• Low data rate

• Device integration

• OWC Underwater comms

– Offshore platforms sensor networks [2]

• Water scattering , attenuation by refraction,

[1] Stefan Schmid, Giorgio Corbellini, Stefan Mangold, and Thomas R. Gross. 2013. LED-to-LED visible light communication networks. In Proceedings of thefourteenth ACM international symposium on Mobile ad hoc networking and computing (MobiHoc ’13). ACM, New York, NY, USA, 1-10.[2] J. A. Simspson et al. “Smart Transmitters and Receivers for Underwater Free-Space Optical Communication”, IEEE JSAC, 5 (30), June 2012

Photos: Disney ©

March 2014 - OQCG Seminars

Ultra-short range OWC

• Chip to Chip comms

– Couplers fibre to chip

• Grating couplers, tappering, …

• Future sensor networks (O’Brien, Oxford)

March 2014 - OQCG Seminars

Future of OWC

• Ultra short range depends on photonic chip

• Short-range depends on consumer adoption (Li-Fi, wearables, …)

• Medium range niche market, established, future depends on the channel impairments solutions and the deployment of OWC networks under extrem situations

• Long-range / ultra long Satellite is OWC the solution?

– VALIDATION OF TURBULENCE MITIGATION TECHNIQUES FORHIGH DATA RATE OPTICAL LINK - ESA Invitation To Tender 7386

– NASA last issues

– DLR and quantum tranmission

• New OWC SME will engage the big players?

March 2014 - OQCG Seminars

Latest news on OWC

“Smartphone concept incorporates LiFi sensor for receiving light-based data” , OLEDCOMM at CES 2014

“Pure LiFi transmits data using light (video)” at MWC 2014

“Charge and receive data with light: TCL Communication/ALCATEL ONETOUCH and Sunpartner Technologies announces the first fully integrated solar smartphone” at MWC 2014

“High-Speed Stock Traders Turn to Laser Beams” at WSJ FEB 2014

“Extreme Test for the ViaLight Laser Communication Terminal MLT-20 – Optical Downlink from a Jet Aircraft at 800km/h”, EADS & DLR Dec 2013

“NASA Historic Demonstration Proves Laser Communication Possible ” by NASA Nov 2013, Lunar Laser Communication Demonstration or LLCD

March 2014 - OQCG Seminars

MWP & OWC?

QKD & OWC?

POF + ACCESS + OWC + …?

And now?

March 2014 - OQCG Seminars

Optical and Quantum Communication Group (OQCG)

iTEAM Research Institute

Universitat Politecnica de Valencia, Spain

http://joaquinperezsoler.blogs.upv.es/

joapeso@upv.es // Gscholar // @joakin_perez

March 2014 - OQCG Seminars

DR JOAQUIN PEREZPOSTDOCTORAL RESEARCH FELLOW