Alex Wyglinski - IEEE VTS UKRI - Cognitive radio - a panacea for RF spectrum scarcity
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Transcript of Alex Wyglinski - IEEE VTS UKRI - Cognitive radio - a panacea for RF spectrum scarcity
COGNITIVE RADIO:
A PANACEA FOR
RF SPECTRUM SCARCITY
Professor Alexander M. Wyglinski Worcester Polytechnic Institute
2
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Presentation Outline
The Information Age
Wireless Spectrum Characterization
Spectrally Agile Waveform Design
Security Issues in Wireless Spectrum
Concluding Remarks
The Information Age
4
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Several Key Innovators
Marconi Shannon Shockley Bardeen Brattain
Wireless
Transmission
Digital
Communications Transistors
Source: Wikipedia
5
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Progress of Technology
6
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Evolution of Wireless Systems
“Cog
nitive
Radio
Com
mun
ications
and
Net
work
s: P
rinc
iple
s and
Pra
ctic
e”
By A
. M
. W
yg
linsk
i, M
. N
eko
vee, Y
. T.
Hou
(Els
evi
er,
Dece
mb
er
20
09
)
7
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Software-Defined Radio Anatomy
PROGRAMMABLE TUNABLE
8
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Sample SDR Platforms
Universal Software Radio Peripheral 2 (USRP2) Unit. COSMIAC FPGA board currently being retrofitted for
better memory access, to add USB functionality and
to make the board SPA compatible.
9
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Mitola & Cognitive Radio
Joseph Mitola III
10
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Cognitive Radio: A Black Box Model
What you want
What you see
What you can do
What you
can tune
11
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Flexible RF Front Ends Needed
88 MHz
5.8 GHz
Can I do this
with just one
RF front end?
12
Cognitive Radio: A Panacea for RF Spectrum Scarcity
RF MEMS Can Help!
A single RF front end
would not normally be
able to support a very
wide frequency range
of operations
Radio Frequency Micro-
Electro-Mechanical
Systems (RF MEMS) can
be used to “tune” the RF
front end to the
corresponding frequency Source: Wireless ICs and MEMS Laboratory,
McGill University
Close-Up of MEMS Tunable LC Filter.
Capacitor
Inductor
13
Cognitive Radio: A Panacea for RF Spectrum Scarcity
RF MEMS
RF MEMS can be used to implement:
Antennas (e.g., fractal antennas)
Filters (e.g., tunable RF bandpass filters)
Oscillators
Real-time operations very difficult to support
Time needed to physically change configurations on the
order of seconds
Compared to the rate at which data is transmitted, this is
considered to be ages!
Spectrum Characterization
15
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Electromagnetic Spectrum
What do you think of when you hear the word
“spectrum”?
16
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Electromagnetic Spectrum
Electromagnetic spectrum is the medium upon which wireless
communications is realized
Only portions of spectrum are suitable for mobile
communications
3-30 Hz
Extremely low frequency (ELF)
30-300 GHz
Extremely high frequency (EHF)
Not desirable: low bandwidth, long propagation range
Not desirable: short propagation range, line-of-sight communication
30-3000 MHz
Desirable: High bandwidth, reasonable propagation range
Radio Frequency range
17
Cognitive Radio: A Panacea for RF Spectrum Scarcity
How Do You Measure Spectrum?
“Cog
nitive
Radio
Com
mun
ications
and
Net
work
s: P
rinc
iple
s and
Pra
ctic
e”
By A
. M
. W
yg
linsk
i, M
. N
eko
vee, Y
. T.
Hou
(Els
evi
er,
Dece
mb
er
20
09
)
Radio Car – circa 1927 (photo courtesy of the Institute for Telecommunications Science (ITS),
NTIA, U.S. Dept. of Commerce)
18
Cognitive Radio: A Panacea for RF Spectrum Scarcity
How Do You Measure Spectrum?
WPI Wireless Innovation Laboratory NSF-sponsored Measurement Campaign – Summer 2008
19
Cognitive Radio: A Panacea for RF Spectrum Scarcity
How Do You Measure Spectrum?
SQUIRRELWeb online
spectrum measurement
portal
Queue-driven spectrum
observatory
Collects specific spectrum
measurements upon user
request
Available at: http://www.spectrum.wpi.edu
20
Cognitive Radio: A Panacea for RF Spectrum Scarcity
How Do You Measure Spectrum?
A map of the forty eight locations close to I-90 between Boston, MA
and West Stockbridge, MA over which the Toyota-sponsored
measurement campaign was conducted in June 2009.
21
Cognitive Radio: A Panacea for RF Spectrum Scarcity
How Much Spectrum Is There?
Spectrum occupancy characteristics in the four mid-size US cities visited during June 2008
NSF-sponsored measurement campaign.
22
Cognitive Radio: A Panacea for RF Spectrum Scarcity
From A Vehicular Perspective
Energy Spectral Density plots for the TV frequencies in the frequency range, 600 – 750 MHz over
550 time sweeps close on I-90 between Boston, MA and West Stockbridge, MA. The measurement
setup was located in a vehicle moving at an average velocity of 60 miles/hr.
S. Pa
ga
da
rai, A
. M
. W
yg
linsk
i, a
nd R
. V
uyyur
u. “
Cha
ract
eri
zation
of
Va
cant
UH
F TV
Cha
nnels
for
Vehi
cula
r D
yna
mic
Sp
ect
rum
Acc
ess
.” P
roce
ed
ing
s of
the
Firs
t IE
EE V
ehi
cula
r N
etw
ork
ing
Conf
ere
nce (To
kyo, Ja
pa
n), O
ctob
er
20
09
.
23
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Total Available Bandwidth
The total available bandwidth for secondary usage at different locations along I-90. S. Pa
ga
da
rai, A
. M
. W
yg
linsk
i, a
nd R
. V
uyyur
u. “
Cha
ract
eri
zation
of
Va
cant
UH
F TV
Cha
nnels
for
Vehi
cula
r D
yna
mic
Sp
ect
rum
Acc
ess
.” P
roce
ed
ing
s of
the
Firs
t IE
EE V
ehi
cula
r N
etw
ork
ing
Conf
ere
nce (To
kyo, Ja
pa
n), O
ctob
er
20
09
.
24
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectral Opportunity Analysis
Maximum contiguous bandwidth and the number of non-contiguous channel blocks at different
locations along I-90. S. Pa
ga
da
rai, A
. M
. W
yg
linsk
i, a
nd R
. V
uyyur
u. “
Cha
ract
eri
zation
of
Va
cant
UH
F TV
Cha
nnels
for
Vehi
cula
r D
yna
mic
Sp
ect
rum
Acc
ess
.” P
roce
ed
ing
s of
the
Firs
t IE
EE V
ehi
cula
r N
etw
ork
ing
Conf
ere
nce (To
kyo, Ja
pa
n), O
ctob
er
20
09
.
Spectrally Agile Waveforms
26
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Opportunistic Spectrum Access
Opportunistic spectrum access (OSA) is a significant
paradigm shift in the way wireless spectrum is
accessed
Instead of PUs possessing exclusive access to licensed
spectrum, SUs can temporarily borrow unoccupied
frequency bands
SUs must respect the incumbent rights of the PUs with
respect to their licensed spectrum
OSA enables greater spectral efficiency and
facilitates greater user and bandwidth capacity
27
Cognitive Radio: A Panacea for RF Spectrum Scarcity
The utilization efficiency of “prime” wireless spectrum
has been shown to be poor
A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548)
OSA Motivation
A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009.
empty empty empty empty
28
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Leveraging the Electrospace
Several dimensions of
the electrospace include
space, time, and
frequency, although
there do exist others
such as code,
polarization, and
directional.
“Cog
nitive
Radio
Com
mun
ications
and
Net
work
s: P
rinc
iple
s and
Pra
ctic
e”
By A
. M
. W
yg
linsk
i, M
. N
eko
vee, Y
. T.
Hou
(Els
evi
er,
Dece
mb
er
20
09
)
29
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Several Possible Approaches
• Secondary transmission in licensed spectrum can be
classified into three categories:
– Cooperative Approach
• Primary and secondary users coordinate with each other regarding
spectrum usage
– Underlay Approach
• Secondary signals transmitted at very low power spectral density;
undetected by primary users
• e.g., ultra wideband (UWB)
– Overlay Systems
• Secondary signals fill in the spectrum unoccupied by primary users
30
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectral Opportunities!
A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548)
A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009.
empty empty empty empty
31
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Underlay Solution
A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548)
A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009.
underlay transmissions
32
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Overlay Solution
A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548)
A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009.
overlay transmissions
33
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Multicarrier Transmission Techniques for
Spectrally Opportunistic Communications
Multicarrier modulation is a variant of the
conventional frequency division multiplexing (FDM)
Orthogonal Frequency Division Multiplexing (OFDM)
an efficient form of multicarrier modulation
In order to utilize unused portions of licensed
spectrum, several subcarriers can be turned OFF to
avoid interfering with the primary signals
Each subcarrier experiences flat-fading and hence
high data-rates are possible if several unused bands
of secondary spectrum are available
34
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Multicarrier Overlay Solution
A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548)
A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009.
multicarrier overlay transmissions
35
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectral Agility In Action!
PU signal!
multicarrier overlay SU
transmission wraps around PU
As seen in this close-up of
the multicarrier overlay
transmission, subcarriers
located within the vicinity
of a PU can be
deactivated in order to
avoid interference with
that signal.
36
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectrally Agile Multicarrier
H. Bog
ucka
, A
. M
. W
yg
linsk
i, S. Pa
ga
da
rai, A
. K
liks.
“Sp
ect
rally
Ag
ile M
ultica
rrie
r
Wa
vefo
rms
for
Op
port
unis
tic
Wir
ele
ss A
ccess
”. IEE
E C
om
mun
ica
tions
Ma
ga
zine
,
June
20
11
.
37
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Major Issue: Out-of-band Emission
Out-of-band (OOB) interference problem with OFDM-based
cognitive radios
Power spectral density of the transmit signal over one
subcarrier:
Mean relative interference to a neighboring legacy system
subband:
38
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Sinc Pulses Have High OOB Levels!
39
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Several Solutions
Cancellation Carriers
Non-data bearing subcarriers whose phase and
amplitude values cancel OOB
Modulated Filter Banks
Attenuates OOB in stopband region
Combine cancellation carriers (CCs) with modulated
filter banks (MFBs) to attenuate OOB emissions
40
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Cancellation Carriers
41
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Filtering with CCs
42
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Hardware Experimentation
Photograph of a spectrally agile wireless transceiver test-bed at Poznan University of Technology,
Poznan, Poland.
Photograph of a spectrally agile wireless transceiver test-bed at Worcester Polytechnic Institute,
Worcester, MA, USA.
43
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectrally Agile Waveform Results
H. Bog
ucka
, A
. M
. W
yg
linsk
i, S. Pa
ga
da
rai, A
. K
liks.
“Sp
ect
rally
Ag
ile M
ultica
rrie
r
Wa
vefo
rms
for
Op
port
unis
tic
Wir
ele
ss A
ccess
”. IEE
E C
om
mun
ica
tions
Ma
ga
zine
,
June
20
11
.
44
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Spectrally Agile Waveform Results
P. K
rysz
kiew
icz,
H. Bog
ucka
, A
. M
. W
yg
linsk
i. "P
rote
ctio
n of
Pri
ma
ry U
sers
in
Dyna
mic
ally
Va
ryin
g R
ad
io E
nvir
onm
ent
: Pra
ctic
al Solu
tions
and
Cha
lleng
es.
"
Acc
ep
ted
for
pub
lica
tion
in the
EU
RA
SIP
Jour
nal on
Wir
ele
ss C
om
mun
ica
tions
and
Netw
ork
ing
, D
ece
mb
er
23
, 2
01
1.
Security Issues
46
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Motivation
Primary User Emulation (PUE) is a serious threat to
opportunistic spectrum access networks
Malicious secondary users can mimic spectral
characteristics of primary users to gain priority
access to wireless channels
Primary (licensed) users have the priority of using the
channel
All the secondary users have equal opportunity to use
the channel
47
Cognitive Radio: A Panacea for RF Spectrum Scarcity
An Example
frequency
I’m a
PU!
I’m a
PU!
I’m a
PU!
I’m a
PU, too!
Get out
of my
way!
48
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Current Detection Techniques
Conventional techniques on their own are not
entirely up to the job!!
Simple energy detector
Significant probability of missed detection
Matched filter detector
Requires specialized hardware and software
Localization based detector
Can only be employed for stationary primary transmitters
with known coordinates
49
Cognitive Radio: A Panacea for RF Spectrum Scarcity
One Approach
Combine several techniques in order to detect the
presence of wireless signals as well as to classify
them:
Energy detection
Cyclostationary feature detection
Artificial neural network
Multilayer perceptron (MLP) employed
50
Cognitive Radio: A Panacea for RF Spectrum Scarcity
“Fingerprinting” Wireless Signals
Spectral coherence function of QPSK signal in an
AWGN channel at 10 dB SNR.
Spectral coherence function of 4FSK signal in an
AWGN channel at 10 dB SNR.
51
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Simulation Results
The detection performance with and without the reliability check. The x-axis
represents SNR value, and the y-axis represents the percentage of correct detection.
Di Pu,
Yua
n Shi
, A
ndre
i Ily
ash
enk
o, A
lexa
nder
M. W
yg
linsk
i. "D
ete
ctin
g P
rim
ary
Use
r Em
ula
tion
Atta
cks
in C
og
nitive
Ra
dio
Netw
ork
s."
Pro
ceed
ing
s of
the IEE
E
Glo
ba
l Te
leco
mm
unic
ations
Conf
ere
nce (H
ous
ton,
TX
, U
SA
), N
ove
mb
er
20
11
.
52
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Experimental Results
Proposed Approach
With Check 98.3%
Without Check 91.5%
The percentage of correct detection with the hardware implementation
Di Pu, Yuan Shi, Andrei Ilyashenko, Alexander M. Wyglinski. "Detecting Primary
User Emulation Attacks in Cognitive Radio Networks." Proceedings of the IEEE
Global Telecommunications Conference (Houston, TX, USA), November 2011.
53
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Additional Enhancements
Action Recognition Techniques
Often employed in image and video processing
applications, action recognition can also be applied to
spectrum measurements
Consists of several parameters:
Feature Vector Construction
Covariance Descriptor of Feature Vectors
Log-covariance Descriptor of Feature Vectors
Concluding Remarks
55
Cognitive Radio: A Panacea for RF Spectrum Scarcity
These Are Interesting Times!
Numerous advances in cognitive radio, dynamic
spectrum access, and software-defined radio have
recently occurred
Secondary access of digital TV spectrum
Ratification of IEEE 802.22, IEEE 802.11af standards
Today’s wireless landscape is quickly changing due
to new capabilities of wireless transceiver devices
Largely due to smaller, faster processing devices
resulting from applications such as smart phones
56
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Still Room For Improvement
There still exists a substantial amount of research
that is needed to make future wireless devices such
as cognitive radio more reliable
Ensuring minimal interference to other wireless
transmissions
Enabling real-time decision-making and transmission
operations
Making RF spectrum access more reliable for everyone
involved
More Information
58
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Contact Info
Professor Alexander Wyglinski
Department of Electrical and Computer Engineering
Worcester Polytechnic Institute
Atwater Kent Laboratories, Room AK230
508-831-5061
http://www.wireless.wpi.edu/
59
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Cognitive Radio Textbook
Available since December 2009 (Academic Press)
20 chapters
End-of-chapter problems (with solutions guide)
Presentation slides for most chapters
Covers physical and network layers, in addition to current platforms and standards
http://www.wireless.wpi.edu/?page_id=29
60
Cognitive Radio: A Panacea for RF Spectrum Scarcity
Software-Defined Radio Textbook
Anticipated publication: Q1
2013 (Artech House Publishers)
10 comprehensive chapters
Fundamentals in signals & systems,
probability, and digital
communications
“Hands on” approach to learning
digital communication concepts
using SDR and Simulink
End-of-chapter problems
Corresponding course lecture slides
61
Cognitive Radio: A Panacea for RF Spectrum Scarcity
References
Alexander M. Wyglinski, Maziar Nekovee, Y. Thomas Hou. Cognitive Radio Communications and Networks: Principles and
Practice, Academic Press, December 2009.
Pawel Kryszkiewicz, Hanna Bogucka, Alexander M. Wyglinski. "Protection of Primary Users in Dynamically Varying Radio
Environment: Practical Solutions and Challenges." Accepted for publication in the EURASIP Journal on Wireless Communications
and Networking, December 23, 2011.
Si Chen, Srikanth Pagadarai, Rama Vuyyuru, Alexander M. Wyglinski, Onur Altintas. “Feasibility Analysis of Vehicular Dynamic
Spectrum Access via Queueing Theory Model.” IEEE Communications Magazine, November 2011.
Srikanth Pagadarai, Adrian Kliks, Hanna Bogucka, Alexander M. Wyglinski. “Non-contiguous Multicarrier Waveforms in
Practical Opportunistic Wireless Systems.” IET Radar, Sonar, and Navigation Journal, vol. 5, no. 6, pp. 674-680, July 2011.
Hanna Bogucka, Alexander M. Wyglinski, Srikanth Pagadarai, Adrian Kliks. “Spectrally Agile Multicarrier Waveforms for
Opportunistic Wireless Access”. IEEE Communications Magazine, June 2011.
Srikanth Pagadarai, Alexander M. Wyglinski. “A Linear Mixed Effects Model of Wireless Spectrum Occupancy.” EURASIP
Journal on Wireless Communications and Networking, August 2010.
Zhou Yuan, Alexander M. Wyglinski. “On Sidelobe Suppression for Multicarrier-Based Cognitive Radio Transceivers.” IEEE
Transactions on Vehicular Technology, May 2010.
Chittabrata Ghosh, Srikanth Pagadarai, Dharma P. Agrawal, Alexander M. Wyglinski. “A Framework for Statistical Wireless
Spectrum Occupancy Modeling.” IEEE Transactions on Wireless Communications, Vol. 9, No. 1, Pages 38-44, January 2010.
Timothy Newman, Daniel DePardo, Alexander Wyglinski, Joseph B. Evans, Rakesh Rajbanshi, Victor R. Petty, Dinesh Datla,
Frederick Weidling, Paul Kolodzy, Michael Marcus, Gary J. Minden, James Roberts. “Measurements and Analysis of Secondary
User Device Effects on Digital Television Receivers.” EURASIP Journal on Advances in Signal Processing – Special Issue on
“Dynamic Spectrum Access for Wireless Networking”, August 2009.
62
Cognitive Radio: A Panacea for RF Spectrum Scarcity
References
Alexander M. Wyglinski. “Changing the Way Wireless Technology Accesses Electromagnetic Spectrum.” EEWeb Pulse
Magazine, Issue 14, 4 October 2011. [ONLINE]: http://www.eeweb.com/pulse/issue-14-2011
Si Chen, Rama Vuyyuru, Onur Altintas, Alexander M. Wyglinski. “Learning in Vehicular Dynamic Spectrum Access Networks:
Opportunities and Challenges.” Proceedings of the International Symposium on Intelligent Signal Processing and
Communication Systems, (Chiang Mai, Thailand), December 2011.
Di Pu, Yuan Shi, Andrei Ilyashenko, Alexander M. Wyglinski. "Detecting Primary User Emulation Attacks in Cognitive Radio
Networks." Proceedings of the IEEE Global Telecommunications Conference (Houston, TX, USA), November 2011.
Si Chen, Rama Vuyyuru, Onur Altintas, Alexander M. Wyglinski. “On Optimizing Vehicular Dynamic Spectrum Access Networks:
Automation and Learning in Mobile Wireless Environments.” Proceedings of the IEEE Vehicular Network Conference
(Amsterdam, The Netherlands), November 2011.
Tayyar Rzayev, Yuan Shi, Anastasios Vafeiadis, Srikanth Pagadarai, Alexander M. Wyglinski. “Implementation of a Vehicular
Networking Architecture Supporting Dynamic Spectrum Access.” Proceedings of the IEEE Vehicular Network Conference
(Amsterdam, The Netherlands), November 2011.
Onur Altintas, Mitsuhiro Nishibori, Takuro Oshida, Yutaka Ihara, Masahiro Saito, Chikara Yoshimura, Youhei Fujii, Kota Nishida,
Kazuya Tsukamoto, Masato Tsuru, Yuji Oie, Rama Vuyyuru, Abdulrahman Al Abbasi, Masaaki Ohtake, Mai Ohta, Takeo Fujii, Si
Chen, Srikanth Pagadarai, Alexander M. Wyglinski. "Demonstration of Vehicle to Vehicle Communications over TV White
Space." Proceedings of the 4th International Symposium on Wireless Vehicular Communications (San Franscisco, CA, USA),
September 2011.
Sean Rocke, Alexander M. Wyglinski. “Geo-Statistical Analysis of Wireless Spectrum Occupancy using Extreme Value Theory.”
Proceedings of the 2011 IEEE Pacific Rim Conference on Communications, Computers, and Signal Processing (Victoria, BC,
Canada), August 2011.
63
Cognitive Radio: A Panacea for RF Spectrum Scarcity
References
Di Pu, Alexander M. Wyglinski. “Primary User Emulation Detection Using Frequency Domain Action Recognition.” Proceedings
of the 2011 IEEE Pacific Rim Conference on Communications, Computers, and Signal Processing (Victoria, BC, Canada), August
2011.
Si Chen, Alexander M. Wyglinski, Rama Vuyyuru, Onur Altintas. “Feasibility Analysis of Vehicular Dynamic Spectrum Access
Via Queueing Theory Model”. Proceedings of the IEEE Vehicular Networking Conference (Jersey City, NJ, USA), Dec. 2010.
Srikanth Pagadarai, Adrian Kliks, Hanna Bogucka, Alexander M. Wyglinski. “On Non-contiguous Multicarrier Waveforms for
Spectrally Opportunistic Cognitive Radio Systems”. Proceedings of the 5th International Waveform Diversity and Design
Conference (Niagara Falls, ON, Canada), August 2010.
Srikanth Pagadarai, Alexander M. Wyglinski, and Rama Vuyyuru. “Characterization of Vacant UHF TV Channels for Vehicular
Dynamic Spectrum Access.” Proceedings of the First IEEE Vehicular Networking Conference (Tokyo, Japan), October 2009.
Zhou Yuan, Srikanth Pagadarai, Alexander M. Wyglinski. “Feasibility of NC-OFDM Transmission in Dynamic Spectrum Access
Networks.” Proceedings of the 2009 Military Communications Conference (Boston, MA, USA), October 18, 2009.
Zhou Yuan and Alexander M. Wyglinski. “Cognitive Radio-Based OFDM Sidelobe Suppression Employing Modulated Filter
Banks and Cancellation Carriers.” Proceedings of the 2009 Military Communications Conference (Boston, MA, USA), October
18, 2009.
Chittabrata Ghosh, Srikanth Pagadarai, Dharma P. Agarwal, and Alexander M. Wyglinski. “Queuing Theory Representation
and Modeling of Spectrum Occupancy Employing Radio Frequency Measurements.” Proceedings of the IEEE Vehicular
Technology Conference (Anchorage, AK, USA), September 20, 2009.
Srikanth Pagadarai and Alexander M. Wyglinski. “A Quantitative Assessment of Wireless Spectrum Measurements for
Dynamic Spectrum Access.” Proceedings of the International Conference on Cognitive Radio Oriented Wireless Networks and
Communications (Hannover, Germany), June 22, 2009.
64
Cognitive Radio: A Panacea for RF Spectrum Scarcity
References
Zhou Yuan, Srikanth Pagadarai, and Alexander M. Wyglinski. “Sidelobe Suppression of OFDM Transmissions using Genetic
Algorithm Optimization.” Proceedings of the IEEE Military Communications Conference (San Diego, CA, USA), November 2008.
Srikanth Pagadarai and Alexander M. Wyglinski. “A Sub-optimal Sidelobe Suppression Technique for OFDM-based Cognitive
Radios.” Proceedings of the IEEE Military Communications Conference (San Diego, CA, USA), November 2008.
Srikanth Pagadarai and Alexander M. Wyglinski. “Novel Sidelobe Suppression Technique for OFDM-Based Cognitive Radio
Transmission.” Proceedings of the IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (Chicago, IL, USA),
October 2008.
Srikanth Pagadarai, Rakesh Rajbanshi, Alexander M. Wyglinski, and Gary J. Minden. “Sidelobe Suppression for OFDM-Based
Cognitive Radios Using Constellation Expansion.” Proceedings of the IEEE Wireless Communications and Networking
Conference (Las Vegas, NV, USA), April 2008.
Dinesh Datla, Alexander M. Wyglinski, and Gary J. Minden. “A Statistical Approach to Spectrum Measurement Processing.”
Proceedings of the 2007 Virginia Tech Symposium on Wireless Personal Communications (Blacksburg, VA, USA), June 2007.
Rakesh Rajbanshi, Victor R. Petty, Dinesh Datla, Frederick Weidling, Daniel DePardo, Paul J. Kolodzy, Michael. J. Marcus,
Alexander M. Wyglinski, Joseph B. Evans, Gary J. Minden, and James A. Roberts. “Feasibility Study of Dynamic Spectrum
Access in Underutilized Television Bands.” Proceedings of the Second IEEE Symposium on New Frontiers in Dynamic Spectrum
Access Networks (Dublin, Ireland), April 2007.
Rakesh Rajbanshi, Qi Chen, Alexander M. Wyglinski, Gary J. Minden, and Joseph B. Evans. “Quantitative Comparison of Agile
Modulation Techniques for Cognitive Radio Transceivers.” Proceedings of the IEEE Consumer Communications and Networking
Conference – Workshop on Cognitive Radio Networks (Las Vegas, NV, USA), January 2007.
Rakesh Rajbanshi, Qi Chen, Alexander M. Wyglinski, Joseph B. Evans, and Gary J. Minden. “Comparative Study of Frequency
Agile Data Transmission Schemes for Cognitive Radio Transceivers.” Proceedings of the First International Workshop on
Technology and Policy for Accessing Spectrum (Boston, MA, USA), July 2006.
Thank You!