Implications of Spectrum
Management for the Air Force
Paul J Kolodzy, PhD
Kolodzy Consulting, LLC
Studies of the RF Spectrum
KOLODZY
CONSULTING, LLC
„
DoD – Defense Science Board, Army Science Board
US Gov’t – FCC (SPTF), WH/DoC
Non-Gov’t – CSIS, Toffler, CSTB, NRC
„
Common Theme:
„
„
¾
¾
¾
Technology continues to increase both the uses of the RF
Spectrum as well as the capacity to more intensively use the
RF Spectrum
Coordination/Cooperation both administratively and
technically is needed to improve capacity
Technology is challenging current spectrum management and
spectrum policy paradigms
Multi-Disciplinary
Not just in Words
“transaction
“highest and costs”
best use”
“OOBE”
KOLODZY
CONSULTING, LLC
Policy
Makers
“auctions”
“Structure
Programming”
Computer
Scientists
“LNA”
“child
processes”
“dB”
“Intermods”
Economists
“Ontologies”
“dynamic
range”
“Provability”
Electrical Engineers, Computer
Scientists, Communications
Engineers, Lawyers, Policy Makers,
Economists, Physicists, Material
Scientists, Pontificators
Electical
Engineers
Summary
KOLODZY
CONSULTING, LLC
„
„
„
Technology for Dynamic Use of the RF Spectrum
continues to improve (DoD and Commercial);
Use of RF Spectrum continues to increase and the
need for more intensive use of RF is necessary to meet
future needs;
USAF needs to address fundamental characteristics of
RF Spectrum needs and uses
¾
¾
More Exploitation of Networking, Smart Antennas, Multi-mode
(RF/non-RF) Technologies
More Intensive Use through Time-Frequency-Space Sharing
with Federal & non-Federal Users
Technology Update
KOLODZY
CONSULTING, LLC
„
„
„
Software Defined Radios Æ neXt Generation
Communications (XG) Æ Cognitive Radios Æ Policy
Radios
XG / Dynamic Spectrum Access Technology has been
demonstrated for both military and commercial
applications
MANET Networking has been demonstrated
successfully with smaller (<50 node) networks
¾
„
Power Amplifier / Filter Technology has lagged
¾
„
Extensions to High Density Networks on-going at DARPA
Multiple Programs at DARPA and other DoD Laboratories
Optical Networking for Tactical Backhaul
¾
TRL-6 Project at DARPA
Layer-3 Interoperability
DARPA - NCRS
KOLODZY
CONSULTING, LLC
Commercial Technology Enablers
KOLODZY
CONSULTING, LLC
time
Smart
Antennas
Orthogonal Frequency
Division Multiple Access (OFDMA)
frequency
256 QAM
Adaptive 64 QAM
Modulation 16 QAM
QPSK
BPSK
„
„
Technology
Technology Enablers
Enablers
¾
¾
¾
¾
¾
¾
Smart
Smart Antennas
Antennas –– Increases
Increases Wireless
Wireless Performance
Performance
Adaptive
Adaptive Modulation
Modulation –– Exploits
Exploits Stronger
Stronger Signals
Signals for
for Increased
Increased Capacity
Capacity
OFDMA
OFDMA –– More
More Efficient
Efficient Resource
Resource Utilization
Utilization
The New Challenge
FDD (Commercial) – TDD (DoD)
Uplink
KOLODZY
CONSULTING, LLC
Uplink/
Downlink
Downlink
~30 to 300 MHz
Block 1
Block 2
Block 1
Block 2
-43 dBW
-43 dBW
AWS-3
-43 dBW
Base – Base
Interference
Mobile – Mobile
Interference
FDD
Downlink
TDD
Uplink
FDD
Downlink
TDD
Uplink
Mismatch between Commercial Technology (commonly FDD) and
DoD Technology (commonly TDD) requires better technology
development to make more compatible
The Computer Science View of
Interference Avoidance
KOLODZY
CONSULTING, LLC
QPSK Interference Spectrum
Shaped QPSK @ 128 kbps
0
Power Spectrum Magnitude (dB)
-10
-20
-30
-40
-50
-60
-70
-80
Tx Spectrum
-90
-100
0
0.5
1
1.5
Frequency (Hz)
2
Rcv Spectrum
2.5
x 10
6
Power Spectrum Magnitude (dB)
Power Spectrum Magnitude (dB)
-20
-40
-60
-80
-100
-120
-140
2.5
3
Survive
2
1.5
2
1
Survive
0.5
6
Frequency (Hz)x 10
0
1
0
-20
-40
-60
-80
-100
2.5
3
Survive
2
1.5
2
1
Survive
0.5
Normal
Transmission Number
6
Frequency (Hz)x 10
0
1
Normal
Transmission Number
Regulatory Rules
KOLODZY
CONSULTING, LLC
Band
1
Band
2
Band
3
Out-of-Band Emissions (OOBE)
OOBE
Intermodulation Distortion (IMD)
f1
„
f2
2f2- f1
Interference Level Dependent Upon
¾
¾
¾
¾
Emitted signal levels
Frequency separation between signals
Transmit and receive filtering
Desired signal level at victim receiver
Near-Far
Scenario
The Radio Engineering View of
Interference
KOLODZY
CONSULTING, LLC
Signal Environment
„ Cumulative
Energy in Receiver Filter Increases
Noise Floor, Reducing Detection Distance
Combination of multi-band operation and high
spectrum use can create significant challenges
¾ High dynamic range vs. low-power consumption
¾ Current technology is challenged to allow
sensitive reception in the presence of strong
signals and densely occupied spectrum
¾
Receiver Output
~20 dBm Increase in
Noise Floor
~88% Reduction
in Spectrum
Availability
DARPA Tuner Utilization Study, PR #8587, Shared
Spectrum Company
Results Shown for Ultra High Quality LNA 10dB Gain,
IIP3 = 50dBm, 10W consumption
“Open Spectrum/Channel” Use
Intermodulation Distortion (IMD)
Signal Power = -70dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -40dBm
Receiver Output without
Additional Signal -31
Present
dBm
Total Input
Total Output
Base Output
-40 dBm
-100
Signal Power = -70dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -31dBm
-90
-90
IMD
-110
Power (dBm) per Hz
-70 dBm
-120
Degradation
-130
-130
-150
-150
57
AWS
Signal 1
„
-120
-140
56
58
Interference
-110
-140
-160
55
Total Input
Total Output
Base Output
-100
Power (dBm) per Hz
IIP3=-7 dBm
KOLODZY
CONSULTING, LLC
59
Frequency (MHz)
60
61
New
AWS
Signal Signal 2
62
63
-160
55
56
57
AWS
Signal 1
58
59
Frequency (MHz)
60
New
Signal
61
AWS
Signal 2
Insertion of Signal May Create Out of Band Interference
¾
¾
Appears proper when viewed as “white space”
Actual result is a reduction in SNR, resulting in potentially harmful
interference
This is why Carrier Colocate Transmitters!
62
63
DSA for Interference Avoidance?!
KOLODZY
CONSULTING, LLC
Radio that Can Estimate the Interference Environment, Can “Search” for Spectral
Regions that Do Not Create Interference for the Radio
Interference-Free Zones?
Dynamic Interference Avoidance Radio Systems combine the
understanding of both the RF environment and the Radio RF
characteristics
Dynamic Interference Avoidance
KOLODZY
CONSULTING, LLC
Signal Power = -50dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -31dBm
Signal Power = -50dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -31dBm
Total Input
Total Output
Base Output
-80
-80
-90
-90
Power (dBm) per Hz
Power (dBm) per Hz
Total Input
Total Output
Base Output
-100
-100
-110
-110
-120
-120
-130
50
-130
52
54
56
58
60
Frequency (MHz)
62
64
66
68
70
50
52
54
Signal Power = -50dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -31dBm
56
58
60
Frequency (MHz)
62
64
66
Total Input
Total Output
Base Output
-80
-80
-90
-90
Power (dBm) per Hz
Power (dBm) per Hz
70
Signal Power = -50dBm, Gain 10 dB, Amplifiers IP3 = -7 dBm
Input Power Level per 1.25 MHz OFDM= -31dBm
Total Input
Total Output
Base Output
-100
-100
-110
-110
-120
-120
-130
50
68
-130
52
54
56
58
60
Frequency (MHz)
62
64
66
68
70
50
52
54
56
58
60
Frequency (MHz)
62
64
66
68
70
NG Radios that are Aware of Interference Effects Can Adapt to Mitigate Effects
Where’s the Action?
circa 2007
KOLODZY
CONSULTING, LLC
TV
Whitespaces
Upper
700 MHz
BRS
UNII
3.5 GHz
US Spectrum Allocations
(Government, Non-Government, Shared)
KOLODZY
CONSULTING, LLC
22%
42%
35%
Spectrum from 322-3,100 MHz:
NTIA regulates 22%
FCC regulates 35%
Shared NTIA/FCC regulates 42%
Frequency Agility and Wideband and Ultra-Wideband Devices,
creates Challenges at the Interfaces between the Different
Allocations
Spectral Utilization
KOLODZY
CONSULTING, LLC
High Peak-to-Average Ratio utilization in some bands provide impetus
for new thinking in RF Spectrum sharing … Technology to provide
insight into utilization is prevalent
RF Spectrum Sharing
Time-Frequency-Space-Angle-etc
KOLODZY
CONSULTING, LLC
Demonstrations of Directionality Orthogonality for RF Spectrum Sharing
have been Successful (Northpoint)
Summary
KOLODZY
CONSULTING, LLC
„
„
„
Technology for Dynamic Use of the RF Spectrum
continues to improve (DoD and Commercial);
Use of RF Spectrum continues to increase and the
need for more intensive use of RF is necessary to meet
future needs;
USAF needs to address fundamental characteristics of
RF Spectrum needs and uses
¾
¾
More Exploitation of Networking, Smart Antennas, Multi-mode
(RF/non-RF) Technologies
More Intensive Use through Time-Frequency-Space Sharing
with Federal & non-Federal Users