doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 1

Extreme Bandwidth- Wireless Area Extreme Bandwidth- Wireless Area Networks Utilizing Terahertz FrequenciesNetworks Utilizing Terahertz Frequencies

Date: 2007-07-06

Name Affiliations Address Phone email David Britz AT&T Labs 180 Park Ave

Florham Park NJ 973 236 6913 dbritz@research.att.com

Authors:

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 2

AbstractAbstract

True gigabit wireless networks will likely strain available FCC defined spectrum. Devices and networks operating in that shared spectrum space will necessarily be expensive to deploy and operate. The author examines the possibility of utilizing spectrum beyond 100Ghz and well into the unregulated spectrum of Terahertz frequencies, to exploit the vast essentially unused spectrum with low cost technology (inefficient) transceiver and modulation methods that allow many people to get in on the new opportunity – creating a large market that then heads toward more efficient usage methods over time.

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 3

To deliver greater bandwidth, every new 802.11 standard

has historically demanded new spectrum allocation!

As an example 802.11n, to deliver 100Mbs requires

spectrum at 40 MHz channels.

So what spectrum will be needed for Gigabit WLAN’s?

How many bits per Hz? (cheap or expensive systems)

Does the FCC even have the available spectrum

needed to support Gigabit WLAN’s?

To follow Moore's Law in bandwidth scaling, perhaps it’s time to consider going above the FCC’s spectrum

purview!

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 4

How many 1 gigabit channels are available (assuming 2.5 Gigahertz channel spacing)?

2 (channels)

3 (channels)

1 (channel)

6 (channels)

8 (channels)

10 (channels)

5 (channels)

4 (channels)

2 (channels)

6 (channels)

10 (channels)

10 (channels)4

(channels)

5 (channels)

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 5

Terahertz Terahertz FrequenciesFrequencies

ter·a·hertz (tĕr'ə-hûrts') n. (Abbr. THz)

One trillion (10 ) hertz.

So what’s it good for?

Truly enormous bandwidth per channel (10-100+ Gbps)!But nature gives you nothing for freeBut nature gives you nothing for freeThink short distances 10 -100 metersThink short distances 10 -100 meters

12

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 6

X RayEnergies

RadioEnergiesUltra Violet

EnergiesFar Infra Red

Energies

0.001µm 0.4µm 0.75µm 3.0µm 30.0µm

1.0mm

Radio Spectrum

Visible LightEnergies

Spectra of Optical, Terahertz Spectra of Optical, Terahertz and Radio Frequenciesand Radio Frequencies

Visible Light

Current Commercial Radio Spectrum

“Optical” Spectrum

Mid Infra RedEnergies

Near Infra RedEnergies

0.91µ 1.5-1.6µ ITU1.3µ 10µ0.85µ

1.0µm 1000.0µ

1.0 µm= 1 Millionth of a Meter

25.4 µ = 1/1000 of an inch75 µ (3/1000”) thickness of human hair

Scale:

“Terahertz” Spectrum

1nm channel @1550nm = 124.8 GHz

1.0 nm = 1 Billionth of a Meter

Wavelength300.0µm1THz

1.0 THz = 1000 GHz (300µm) Thickness of 4 human hairs

0.4 -0.75 µm= Visible light

10 THz 300 GHz FCC Cutoff

100 THz

1536

Relative Power

1

0.5

100 GHz spacing

Current Commercial Optical Fiber & FSO Spectrum

There is plenty of unused spectrum out thereWe Just haven't figured out how to use it

100 GHz

Advanced Laser designs provide optical channels at

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 7

Optical Photon EmissionTightly bound electrons can only move when provided discreet (quantized ) excitation energy matching a particular shell radius. Electrons closer to the binding nucleous require more excitation energy. The higher theenergy the shorter the wavelength(higher frequency) photon released.

-

Conservation of Energy Excitation energy gained by an accelerated electron (momentum) is released by the electron as an electromagnetic disturbance called a photon

λ

Terahertz Photon EmissionUnbound electrons oscillating within a magnetic field (Free Electron Laser) Intermediate excitation levels, intermediate wavelengths released

λ-

e‾

+

Radio Photon EmissionLoosely bound electrons jumping between the outer electron shells of conductor atoms. Lower energy excitation needed,lower energy (longer wavelength) Released.

-

+

-

-

λe‾

+

+

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 8

The Absorption Chasm Between The Optical And Radio Electromagnetic Spectrum

TerahertzTerahertz

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 9

100 THz3 µm

10 THz

30 µm

1 THz

0.30 mm

100 GHz3 mm

10 GHz30 mm

0.1

100.0

1000

1.0

10.0

ATTEN

UA

TIO

N

ATTEN

UA

TIO

N

dB

/Km

dB

/Km

DRIZZL 0.25mm/Hr

Heavy Rain 25mm/Hr

Deluge 150mm/Hr

FOG (0.1gm3

Visibility 50m

20”

1Atm

H2O

H2O

H2O

H2O

CO2

CO2

CO2

O2

O2

H2O

1000 THz0.3µm

Visible MillimeterSub-MillimeterInfrared 0.01

O3

Avoiding Deep Molecular Absorption Bands Avoiding Deep Molecular Absorption Bands

Broadening IR spectrum into longer wave

Broadening Radio spectrum into Sub Millimeter wave 1000 dB/Km wall

FCC 300GHzRadio Boundary

Existing

Optical Fiber & FSOC

Commercial RF

Spectrum

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 10

AstronomyAstronomy• Orbital and ground based study of cold interstellar molecular clouds

of singly ionized nitrogen and carbon monoxide -contributing to early galactic formation

Remote SensingRemote Sensing• Atmospheric sensing of pollutants and composition

Medical ImagingMedical Imaging• Penetrates non polar materials, skin and soft tissue may be a safe X-

Ray replacement

Materials AnalysisMaterials Analysis• THz frequencies interact aggressively with polar molecules (water),

most molecules have vibration and rotational emission and absorption spectral

SecuritySecurity• Terahertz detectors can now detect passive emissions from human

bodies and objects hidden within clothing• Terahertz scanners can penetrate sealed packages• Return spectra can identify material composition (spectral fingerprint)

Indoor and Outdoor Wireless LANsIndoor and Outdoor Wireless LANs(10-100+ Gbps)• Radio tags• Intelligent home device interface• Personal Space Broadband Networks

Terahertz & Extreme Gigahertz frequencies can propagate like radio, but be brought to a focus like light.

ESA -Herschel Spacecraft

Terahertz Imaging

100 Gigahertz

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 11

FSOC P to P& MeshP to MP

10 feet 100 feet 1 mile 10 miles

1

PeakDataRate

Range

Wider Area,More Mobility

10

100

4G Wireless NAN

2.4 & 5 GHz

4G H/S Wireless LAN2.4 & 5 GHz Unlicensed

3G/802.16 WirelessVarious Bands

3G/MAN Fixed or Pedestrian

Higher Rate,Less Mobility

Meg

ab

its

pe

r S

eco

nd

/Us

er

2.5G Mobile/Pedestrian

3G/MAN Mobile.1

Bluetooth

PANs2.4GHz and UWB

ZigBee (Europe)

2/2,5G Wireless800 MHz, 2 GHz

ZigBee

ZigBee (US)

UWB

Slide provided by Robert R. Miller, Director AT&T Labs Research

THzTHz

Shrinking Radio Cell SizeShrinking Radio Cell Size

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 12

Electronic Entertainment, Gaming, Shopping, Smart Home And Medical Monitoring PAN’s

Education, Business Information And Telepresence

Services

FoodMartFoodMart

In Home Terahertz Network

Entertainment

Productivity

2005+ Vision

GA

TEW

AY

UtilityIP H

ome

QoS

Net

wor

ks

Metallic Narrowband

Optical Fiber

LegacyEqpt.

Wireless4G RadioFSOC

AudioVideoTelematicsVehicle MonitoringEtc…

WirelessTerahertzTV

VCRAudio SystemRemote ControlCamcorder...PCPrinterScanner...PhoneFaxEnvironmentalSecurityMedical & PAN’sDomestic apps…

WirelessTerahertz

Electronic Entertainment, Gaming, Shopping, Smart Home And Medical Monitoring PAN’s

Education, Business Education, Business Information AndInformation And Telepresence Telepresence

ServicesServices

FoodMartFoodMart

In Home Terahertz NetworkIn Home Terahertz Network

Entertainment

Productivity

2005+ Vision

GA

TEW

AY

UtilityIP H

ome

QoS

Net

wor

ks

Metallic NarrowbandMetallic Narrowband

Optical Fiber

LegacyEqpt.

WirelessWireless4G Radio4G RadioFSOCFSOC

AudioVideoTelematicsVehicle MonitoringEtc…

WirelessTerahertzTV

VCRAudio SystemRemote ControlCamcorder...PCPrinterScanner...PhoneFaxEnvironmentalSecurityMedical & PAN’sDomestic apps…

WirelessTerahertz

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 13

Terahertz (GigE) up/down link Terahertz (GigE) up/down link From terminal to airplaneFrom terminal to airplane

Terminal Link

(fiber back to building)

Airplane Link

Short distance Terahertz links use low power safe wavelengths and are capable of transmittingGigE capacity

Autonomous reading (imaging Autonomous reading (imaging scanning) of freight destination tagsscanning) of freight destination tags

In-Plane broadband connectivityIn-Plane broadband connectivity

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 14

3 Tiered Overlay / Underlay3 Tiered Overlay / Underlay Optical Fiber, FSOC, Terahertz Access NetworkOptical Fiber, FSOC, Terahertz Access Network

Layers are transparent and non-interfering

with each other

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 15

Nano Wire Terahertz Nano Wire Terahertz detector chip level devicedetector chip level device

University at Buffalo; Andrea Markelz and Jonathan Bird

MIIM Terahertz detector announced May 16th 2006 EE Times

2 µm

SiO2 encapsulated Nb SiO2 encapsulated Nb microbolometer Arraymicrobolometer Array Free electron laser

producing terahertz radiation from localized surface charges moving across a grating

Vermont PhotonicsVermont Photonics An electromagnetic wave is produced by this broadband short-pulse terahertz source when a dc bias is placed across the antenna and an ultra short pump-laser pulse is focused in the gap.

Terahertz wireless links will connect the customer or device to the Terahertz wireless links will connect the customer or device to the surrounding network or to other devices via surrounding network or to other devices via short distanceshort distance, ,

intelligent, cooperativeintelligent, cooperative and and widely distributedwidely distributed In-building and terrestrial wireless access points.In-building and terrestrial wireless access points.

(Micro - Municipality model)(Micro - Municipality model)

Examples Of Terahertz Sources and ReceiversExamples Of Terahertz Sources and Receivers

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 16

Creating Imaging systems at Terahertz frequencies Creating Imaging systems at Terahertz frequencies is conceptually and practically easy.is conceptually and practically easy.

Building a robust communications infrastructure is Building a robust communications infrastructure is not!not!

P-to-P

P-to-MP

Free Space Terahertz Free Space Terahertz TransmissionTransmission

LOSLOS

O to T

Optical Signal

Electromagnetically

Driven Modulators

10¹² Hertz

Optical SignalSource

T to E

Tx ModuleRx Module

Optical Optical ModulationModulation

RF Signal RF Signal Processing Processing

AD

AD

Demodulator

Decoder

Data

BasebandQ

I

Direct Optical Signal ProcessingT-to-O?

Phase

Based onBased on maturing transceiver devices, maturing transceiver devices, Bandwidth beyond 100+GbpsBandwidth beyond 100+Gbps are possibleare possible

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 17

Groups and Standards Groups and Standards ActivitiesActivities

•http://www.thznetwork.org/wordpress•The Terahertz Technology Forum of Japan•Terahertz Science and Technology Network, USA•The Virtual Journal of Terahertz Science and Technology•GODOT, a European consortium of THz groups•IEEE 802.15, TG 3c WPAN, IEEE P802.15 SCwng

Conferences

ITW - International Terahertz Workshop (Sandbjerg, Denmark, September 17-19, 2000)

The 2004 DOE-NSF-NIH Report on Opportunities in THz ScienceOSA Topical Meeting on Optical Terahertz Science and Technology

(Orlando FL, March 14-16, 2005)IRMMW - THz 2006 (Shanghai, Sept. 18-22, 2006)

SPIE East THz Physics, Devices and Systems (Boston Oct 1-4 2006) The THz center at RPI CUOS, University of Michigan University of California, Berkeley Columbia University Case Western Univ. of Alberta, Edmonton Center for Terahertz Science and Tech, UCSB Oklahoma State University NJIT Purdue University University of Chicago Oregon State University Georgia Tech Syracuse University Colgate University Univ. of Maryland Picometrix, Inc. (home of the T-Ray 2000TM) Physical Sciences, Inc. Los Alamos National Laboratory Yale University SUNY Buffalo Microwave Laboratory, Ohio State University Jefferson Lab University of Toronto UMBC Johns Hopkins University

Research & Development

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 18

Use of the radio spectrum has seen the upper frequency for communications increase about a decade every 20 years. At this rate, by 2020 0.5 to 1THz will be used for wireless communications

T.S. Bird 2004 (CSIRO ICT Centre)

Indoor and Terrestrial Wireless Personal Space NetworksIndoor and Terrestrial Wireless Personal Space Networks Key challenges will be;• Inherent atmospheric attenuation conditions• Inter-room isolation (doesn't go through walls---good or bad?)• Network planning for multi-layered small-cell dynamic cluster configurability• Minimize network backhaul, intelligent edge and localized cluster routing (rapid cell transit and handoffs)• Physical layer and device interoperability standards (IEEE 802.11/15. 3c, ZigBee IEEE 802.15.4 Intelligent home/commercial sensors, device interoperability, common air interface).• Localized intelligent cluster element coordination and management, (high density reuse of channel frequencies and inter-device cooperation). • Device power (input and transmit)• Suitable transceivers• System and device cost• Mass distribution and deployment (smart dust model).

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 19

Indoor and Terrestrial Wireless Personal Space Networks Take Away

Key Advantages;

• Bandwidth well beyond any existing wireless technology

•No FCC licensing or spectrum allocation, Terahertz is unlicensed spectrum

• Terahertz starts at 300GHz – not so far from existing 90-100GHz technology and development experience

• Like any new frontier, Terahertz users can afford to be initially greedy and wasteful of their spectrum resource since there is so much of it to exploit. This exploitation and growing market in turn encourages the creation of low cost (inefficient) transceiver and modulation methods that allow many people to get in on the new opportunity – creating a large market that then heads toward more efficient usage methods over time. Conversely increasingly expensive but efficient signal and channel processing methods are critical for today's radio spectrum management as the availability of radio spectrum is being increasingly challenged by competitive demands for that limited spectrum

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 20

Thank YouThank You

David BritzDavid Britz

AT&T Shannon LabsAT&T Shannon Labsdbritz@research.att.com dbritz@research.att.com

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 21

Empirical relationship based on measured liquid water content and using analytic expression based on Mie scattering calculations.

Ground effect

microclimate

Ground Effect On FogGround Effect On Fog

Courtesy of Christos Kontogeorgakis Virginia Polytechnic Institute and State University

doc.: IEEE 802.11-07/2068r0

Submission

July 2007

David Britz AT&T LabsSlide 22

At Low temperatures the peak of the blackbody power curve lies in the THz range. At Low temperatures the peak of the blackbody power curve lies in the THz range.

The dashed line is the wave number at 1THz, wave numbers from 3.3 to 333.3cm ¹ The dashed line is the wave number at 1THz, wave numbers from 3.3 to 333.3cm ¹

corresponds to 0.1 to 10THz.corresponds to 0.1 to 10THz.