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July 2007
David Britz AT&T Labs
Slide 1
doc.: IEEE 802.11-07/2068r0
Submission
Extreme Bandwidth- Wireless Area Networks 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 [email protected]
Authors:
July 2007
David Britz AT&T Labs
Slide 2
doc.: IEEE 802.11-07/2068r0
Submission
Abstract
[ 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. ]
July 2007
David Britz AT&T Labs
Slide 3
doc.: IEEE 802.11-07/2068r0
Submission
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!
July 2007
David Britz AT&T Labs
Slide 4
doc.: IEEE 802.11-07/2068r0
Submission
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)
July 2007
David Britz AT&T Labs
Slide 5
doc.: IEEE 802.11-07/2068r0
Submission
Terahertz Frequenciester·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 free
Think short distances 10 -100 meters
12
July 2007
David Britz AT&T Labs
Slide 6
doc.: IEEE 802.11-07/2068r0
Submission
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 and 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
July 2007
David Britz AT&T Labs
Slide 7
doc.: IEEE 802.11-07/2068r0
Submission
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‾
+
+
July 2007
David Britz AT&T Labs
Slide 8
doc.: IEEE 802.11-07/2068r0
Submission
The Absorption Chasm Between The Optical And Radio Electromagnetic Spectrum
Terahertz
July 2007
David Britz AT&T Labs
Slide 9
doc.: IEEE 802.11-07/2068r0
Submission
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
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
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
July 2007
David Britz AT&T Labs
Slide 10
doc.: IEEE 802.11-07/2068r0
Submission
Astronomy• Orbital and ground based study of cold interstellar molecular clouds of
singly ionized nitrogen and carbon monoxide -contributing to early galactic formation
Remote Sensing• Atmospheric sensing of pollutants and composition
Medical Imaging• Penetrates non polar materials, skin and soft tissue• may be a safe X-Ray replacement
Materials Analysis• THz frequencies interact aggressively with polar molecules (water), most
molecules have vibration and rotational emission and absorption spectral
Security• 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 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
July 2007
David Britz AT&T Labs
Slide 11
doc.: IEEE 802.11-07/2068r0
Submission
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
THz
Shrinking Radio Cell Size
July 2007
David Britz AT&T Labs
Slide 12
doc.: IEEE 802.11-07/2068r0
Submission
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 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
July 2007
David Britz AT&T Labs
Slide 13
doc.: IEEE 802.11-07/2068r0
Submission
Terahertz (GigE) up/down link from terminal to airplane
Terminal Link
(fiber back to building)
Airplane Link
Short distance Terahertz links use low power safe wavelengths and are capable of transmitting GigE capacity
Autonomous reading (imaging scanning)
of freight destination tags
In-Plane broadband connectivity
July 2007
David Britz AT&T Labs
Slide 14
doc.: IEEE 802.11-07/2068r0
Submission
3 Tiered Overlay / Underlay Optical Fiber, FSOC, Terahertz Access Network
Layers are transparent and non-interfering
with each other
July 2007
David Britz AT&T Labs
Slide 15
doc.: IEEE 802.11-07/2068r0
Submission
Nano Wire Terahertz detector 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 microbolometer Array Free electron laser
producing terahertz radiation from localized
surface charges moving across a grating
Vermont Photonics An electromagnetic wave is produced by this broadband short-pulse terahertz source when a dc bias is placed across the antenna and an ultrashort pump-laser pulse is focused in the gap.
Terahertz wireless links will connect the customer or device to the surrounding network or to other devices via short distance,
intelligent, cooperative and widely distributed In-building and terrestrial wireless access points.
(Micro - Municipality model)Examples Of Terahertz Sources and Receivers
July 2007
David Britz AT&T Labs
Slide 16
doc.: IEEE 802.11-07/2068r0
Submission
Creating Imaging systems at Terahertz frequencies is conceptually and practically easy.
Building a robust communications infrastructure is not!
P-to-P
P-to-MP
Free Space Terahertz Transmission
LOS
O to T
Optical Signal
Electromagnetically
Driven Modulators
10¹² Hertz
Optical SignalSource
T to E
Tx ModuleRx Module
Optical Modulation RF Signal Processing
AD
AD
Demodulator
Decoder
Data
BasebandQ
I
Direct Optical Signal ProcessingT-to-O?
Phase
Based on maturing transceiver devices, Bandwidth beyond 100+Gbps are possible
July 2007
David Britz AT&T Labs
Slide 17
doc.: IEEE 802.11-07/2068r0
Submission
Groups and Standards Activities
•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
July 2007
David Britz AT&T Labs
Slide 18
doc.: IEEE 802.11-07/2068r0
Submission
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 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).
July 2007
David Britz AT&T Labs
Slide 19
doc.: IEEE 802.11-07/2068r0
Submission
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
July 2007
David Britz AT&T Labs
Slide 20
doc.: IEEE 802.11-07/2068r0
Submission
Thank You
David Britz
AT&T Shannon [email protected]
July 2007
David Britz AT&T Labs
Slide 21
doc.: IEEE 802.11-07/2068r0
Submission
Empirical relationship based on measured liquid water content and using
analytic expression based on Mie scattering calculations.
Ground effect microclimate
Ground Effect On Fog
Courtesy of Christos Kontogeorgakis Virginia Polytechnic Institute and State University
July 2007
David Britz AT&T Labs
Slide 22
doc.: IEEE 802.11-07/2068r0
Submission
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
corresponds to 0.1 to 10THz.