Transcript July 2007 - IEEE Mentor

July 2007
doc.: IEEE 802.11-07/2068r0
Extreme Bandwidth- Wireless Area
Networks Utilizing
Terahertz
Frequencies
Date: 2007-07-06
Authors:
Name
Affiliations
Address
Phone
email
David Britz
AT&T Labs
180 Park Ave
Florham Park NJ
973 236 6913
[email protected]
Submission
Slide 1
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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. ]
Submission
Slide 2
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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!
Submission
Slide 3
David Britz AT&T Labs
July 2007
4
(channels)
doc.: IEEE 802.11-07/2068r0
5
(channels)
4
2
2
3
(channels)
(channels)
10
(channels)
(channels)
5
(channels)
6
(channels)
1
6
(channel)
8
(channels)
(channels)
10
(channels)
10
(channels)
(channels)
How many 1 gigabit channels are available
Submission
(assuming 2.5 Gigahertz channel spacing)?
Slide 4
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Terahertz Frequencies
ter·a·hertz (tĕr'ə-hûrts')
n. (Abbr. THz)
One trillion (10 12) 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
Submission
Slide 5
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
100 GHz spacing
Relative Power
Advanced Laser designs provide
1
optical channels at
Scale:
75 µ (3/1000”) thickness of human hair
25.4 µ = 1/1000 of an inch
0.4 -0.75 µm= Visible light
0.5
1536
1.0 µm= 1 Millionth of a Meter
1.0 nm = 1 Billionth of a Meter
1.0 THz = 1000 GHz (300µm)
Thickness of 4 human hairs
There is plenty of unused spectrum out there
We Just haven't figured out how to use it
Current Commercial Optical
Fiber & FSO Spectrum
Current Commercial
Radio Spectrum
1.0mm
X Ray
Energies
Ultra Violet
Energies
Wavelength 0.001µm
Visible Light
Energies
Near Infra Red Mid Infra Red
Energies
Energies
0.85µ
0.4µm Visible Light 0.75µm
0.91µ 1.3µ
1.5-1.6µ ITU
“Optical”
Spectrum
1nm channel @1550nm
= 124.8 GHz
30.0µm
300.0µm
1THz
“Terahertz”
Spectrum
10 THz
Spectra of Optical, Terahertz
and Radio Frequencies
Submission
10µ
3.0µm
100 THz
1.0µm
Slide 6
Radio
Energies
Far Infra Red
Energies
1000.0µ
100 GHz
Radio Spectrum
300 GHz FCC Cutoff
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Conservation of Energy
Excitation energy gained by an accelerated electron (momentum)
is released by the electron as an electromagnetic disturbance called a photon
λ
+
Radio Photon Emission
Optical Photon Emission
Tightly 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 the
energy the shorter the wavelength
(higher frequency) photon released.
+
-
+
Loosely bound electrons jumping
between the outer electron shells
of conductor atoms.
Lower energy excitation needed,
lower energy (longer wavelength)
Released.
λ
e‾
+
-
-
Terahertz Photon
Emission
Unbound electrons oscillating
within a magnetic field (Free
Electron Laser) Intermediate
excitation levels, intermediate
wavelengths released
Submission
e‾
λ
-
Slide 7
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
The Absorption Chasm Between The Optical And Radio
Electromagnetic Spectrum
Terahertz
Submission
Slide 8
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Broadening IR spectrum into
longer wave
Broadening Radio spectrum
into Sub Millimeter wave
1000
1000 dB/Km wall
H2O
FOG (0.1gm3
Commercial RF
Visibility 50m
Spectrum
Optical
Fiber &
FSOC
CO2
H2O
O2
Heavy Rain
25mm/Hr
10.0
H2O
O2
CO2
CO2
H2O
1.0
H2O
20”
DRIZZL 0.25mm/Hr
ATTENUATION
dB/Km
Deluge
150mm/Hr
Existing
100.0
1Atm
0.1
O3
Infrared
Visible
1000 THz
0.3µm
100 THz
3 µm
Sub-Millimeter
10 THz
1 THz
30 µm
0.30 mm
Avoiding Deep Molecular Absorption Bands
Submission
Slide 9
Millimeter
100 GHz
3 mm
FCC 300GHz
Radio Boundary
0.01
10 GHz
30 mm
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Terahertz & Extreme Gigahertz frequencies can propagate like
radio, but be brought to a focus like light.
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
ESA -Herschel
Spacecraft
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)
•
•
•
Submission
Terahertz 100 Gigahertz
Imaging
Radio tags
Intelligent home device interface
Personal Space Broadband Networks
Slide 10
David Britz AT&T Labs
July 2007
Peak
Data
Rate
Megabits per Second/User
100
THz
doc.: IEEE 802.11-07/2068r0
FSOC P to P
& Mesh
P to MP
Higher Rate,
Less Mobility
UWB
4G H/S Wireless LAN
2.4 & 5 GHz Unlicensed
10
4G Wireless
NAN
Shrinking Radio Cell Size
2.4 & 5 GHz
1
Bluetooth
3G/MAN Fixed or Pedestrian
3G/802.16 Wireless
Various Bands
ZigBee
.1
PANs
Wider Area,
More Mobility
3G/MAN Mobile
2.4GHz and UWB
ZigBee (US)
ZigBee (Europe)
10 feet
2.5G Mobile/Pedestrian
100 feet
1 mile
Slide provided by Robert R. Miller, Director AT&T Labs Research
Submission
Slide 11
2/2,5G Wireless
800 MHz, 2 GHz
10 miles
Range
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Education, Business
Information And
Telepresence
Services
In Home Terahertz Network
Optical Fiber
Metallic Narrowband
Submission
GATEWAY
Wireless
4G Radio
FSOC
IP Home QoS Networks
2005+ Vision
Legacy
Eqpt.
Wireless
TVTerahertz
Entertainment
Productivity
Utility
VCR
Audio System
Remote Control
Camcorder...
PC
Printer
Scanner...
Phone
Fax
Environmental
Security
Medical & PAN’s
Domestic apps…
Slide 12
Electronic Entertainment,
Gaming, Shopping, Smart Home
And Medical Monitoring PAN’s
Wireless
Terahertz
Audio
Video
Telematics
Vehicle
Monitoring
Etc…
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Autonomous reading (imaging scanning)
of freight destination tags
Terminal Link
(fiber back to building)
Airplane
Link
Short distance Terahertz
links use low power safe
wavelengths and are
capable of transmitting
GigE capacity
Terahertz (GigE) up/down link from
terminal to airplane
In-Plane broadband connectivity
Submission
Slide 13
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Layers are transparent
and non-interfering
with each other
3 Tiered Overlay / Underlay
Submission
Optical Fiber, FSOC, Terahertz Access Network
Slide 14
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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
MIIM Terahertz detector
announced May 16th 2006 EE Times
2 µm
Nano Wire Terahertz
detector chip level device
University at Buffalo; Andrea Markelz and Jonathan Bird
SiO2 encapsulated Nb
microbolometer Array
Submission
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.
Slide 15
Free electron laser
producing terahertz
radiation from localized
surface charges moving
across a grating
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Creating Imaging systems at Terahertz frequencies
is conceptually and practically easy.
Building a robust communications infrastructure is not!
Optical Modulation
Electromagnetically
Driven Modulators
10¹² Hertz
Optical
Signal
Source
Free Space Terahertz
Transmission
LOS
Rx Module
Tx Module
Demodulator
I
Decoder
AD
P-to-P
Phase
Optical
Signal
AD
Q
P-to-MP
Baseband
T to E
O to T
Based on maturing transceiver devices,
Bandwidth beyond 100+Gbps are possible
Submission
RF Signal
Processing
Slide 16
Direct Optical
Signal Processing
T-to-O?
David Britz AT&T Labs
Data
July 2007
doc.: IEEE 802.11-07/2068r0
•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
Groups and Standards
Activities
Conferences
ITW - International Terahertz Workshop (Sandbjerg, Denmark,
September 17-19, 2000)
The 2004 DOE-NSF-NIH Report on Opportunities in THz Science
OSA 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)
Research
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
Submission
Slide 17
& Development
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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).
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)
Submission
Slide 18
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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
Submission
Slide 19
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Thank You
David Britz
AT&T Shannon Labs
[email protected]
Submission
Slide 20
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
Empirical relationship based on
measured liquid water content and using
analytic expression based on Mie
scattering calculations.
Ground effect
microclimate
Courtesy of Christos Kontogeorgakis Virginia Polytechnic Institute and State University
Ground Effect On Fog
Submission
Slide 21
David Britz AT&T Labs
July 2007
doc.: IEEE 802.11-07/2068r0
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 333.3cm¹
corresponds to 0.1 to 10THz.
Submission
Slide 22
David Britz AT&T Labs