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April 19, 2023© 2003 General Dynamics, All rights reserved.
SDR Technology Implementation forthe Cognitive Radio
Bruce Fette PhD
Chief ScientistGeneral Dynamics Decision Systems
April 19, 2023 2© 2003 General Dynamics, All rights reserved.
Cognitive Radio* is Built on SDR*
We must start with a Software Defined Radio as a basic
platform on which to build a Cognitive Radio
Cognitive Radio can provide the spectral awareness
technology to support FCC initiatives in Spectral Use
*SDR and Cognitive Radio are terms coined by Dr. Joe Mitola - see appendices for references
April 19, 2023 3© 2003 General Dynamics, All rights reserved.
Definition of SDR
From FCC NPRM*: “We view software defined radios as the
result of an evolutionary process from purely hardware-based
equipment to fully software-based equipment. In this regard, the
process can be roughly described in three stages
1. Hardware driven radios: Transmit frequencies, modulation type and other radio frequency (RF) parameters are determined by hardware and cannot be changed without hardware changes.
2. Digital radios: A digital radio performs part of the signal processing or transmission digitally, but is not programmable in the field
3. Software Defined Radios:. All functions, modes and applications can be configured and reconfigured by software.
*Notice of Proposed Rule Making (NPRM) 8/12/00
April 19, 2023 4© 2003 General Dynamics, All rights reserved.
Definition of SDR - Continued
SDR Forum: 4. SW defines all waveform properties, cryptography and
applications, is re-programmable, and may be upgraded in
the field with new capabilities Importance of Standards (APIs)
5. HW Interfaces, RF services, Operating Environment,
Application to Radio Interfaces
April 19, 2023 5© 2003 General Dynamics, All rights reserved.
SDR Technology
Technology fundamentals:
Digital Signal Processors (DSPs) provide virtually infinite
programmability
All modulation, cryptography, protocols, and source coding
(voice, data, imagery) are established using software
Many types of modulation can be accomplished over a broad
range of frequencies, thereby an SDR is capable of servicing
more than one class of service
Field serviceable, when requirements change, upgrades and
modifications are relatively easy to execute
April 19, 2023 6© 2003 General Dynamics, All rights reserved.
SDR Standardized Architecture Supports Both Current and Future Applications
FDMA, TDMA, CDMA, TDD
AM, FM, MFSK, MPSK, MQAM, CPM, SSB, DSSS …
DES, 3DES, AES, MeXe
Trunked Radio, APCO-25, GSM, Iridium, 802.11..
Tone Coded Squelch, CVSD, LPC, VSELP, AMBE, ….
It’s just a matter of software!
April 19, 2023 7© 2003 General Dynamics, All rights reserved.
Building the Cognitive Radio using SDR Technology - The SDR Radio is Available Now!
SDR drives the Cognitive Radio concept that will provide the spectral awareness technology supporting the FCC’s Spectral Use initiatives
SDR is a proven, flexible, COTS technology platform
SDR Technology is in Production and Available Now
New Announcements
Coming Soon
April 19, 2023 8© 2003 General Dynamics, All rights reserved.
Cognitive Radio Means “Smart” and “Alert”
It knows where it is
It knows what services are available, for example, it can identify then use empty spectrum to communicate more efficiently
It knows what services interest the user, and knows how to find them
It knows the current degree of needs and future likelihood of needs of its user
Learns and recognizes usage patterns from the user
Applies “Model Based Reasoning” about user needs, local content, environmental context
April 19, 2023 9© 2003 General Dynamics, All rights reserved.
How Does a Cognitive Radio Get So Smart?
External Intelligence Sources
Mitola, “Cognitive Radio for Flexible Mobile Multimedia Communications”, IEEE Mobile Multimedia Conference, 1999, pp3-10
OrientEstablish Priority
PlanNormal
Generate Alternatives(Program Generation)Evaluate Alternatives
Register to Current Time
DecideAlternate Resources
Initiate Process(es)(Isochronism Is Key)
Act
Learn
Save Global States
Set DisplaySend a Message
ObserveReceive a Message
Read Buttons
OutsideWorld
NewStates
The Cognition Cycle
PriorStates
Pre-process
Parse
ImmediateUrgent
Infer on Context Hierarchy
April 19, 2023 10© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette That Can Be Implemented on Existing SDR / Cognitive Radio
• Infrastructure Based Approaches
Possible Infrastructure Reuse - spread economic support base
Existing examples of Spectrum sharing Protocols
A) Trunked radio
B) Cellular spectrum borrowing
C) Demand Assigned Multiple Access (DAMA)(demand assigned time
sharing)
Infrastructure Supports wide Range of Spectrum Management Policies
Match Requirements, Priorities, Spectral Mask of Owners
April 19, 2023 11© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Cognitive Radios can adopt new etiquettes for new standards
o Possible Demonstrations using existing SDRs
Spectrum rental transactions
Spectral Availability (Borrow) Beacon
Local Spectrum Utilization Database Server (time, freq, code, space, power,
modulation)
Spectral Noise temperature (Kolodzy, 2002)
RTS - CTS handshake (handshake includes local spectral activity model at each end of link, as well as BW, packet size, TX
PWR for APC). Minimizes hidden node problem
Underlay, Overlay, Interweave
• Distributed techniques - Possible Demonstrations
April 19, 2023 12© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
April 19, 2023 13© 2003 General Dynamics, All rights reserved.
SDR Finds Frequency - Time Opportunities Spectral Awareness Etiquette
Existing Signals
Detailed Signal Parameters
Deployed waveforms
April 19, 2023 14© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
April 19, 2023 15© 2003 General Dynamics, All rights reserved.
Opportunities for Spectral Reuse Amongst Periodic Signals
April 19, 2023 16© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
April 19, 2023 17© 2003 General Dynamics, All rights reserved.
Time - Frequency - Space Each Domain has Opportunities for Spectral Reuse
T1
R1,R4
T2
T3R3
R3,T4
InterferingSignal PlacedIn Null
Transmitter forms Beam Toward Intended RecipientReceiver forms Null Toward Interference Sources
April 19, 2023 18© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
Adaptive Bit Loading onto OFDM carriers based on SNR
April 19, 2023 19© 2003 General Dynamics, All rights reserved.
OFDM Interference Avoidance
1
2
3
00.5
11.5
22.5
x 106
-100
-80
-60
-40
-20
0
Transmission NumberFrequency (Hz)
Pow
er S
pec
tru
m M
agni
tude
(dB
)
1
2
3
00.5
11.5
22.5
x 106
-140
-120
-100
-80
-60
-40
-20
Transmission NumberFrequency (Hz)
Pow
er S
pec
tru
m M
agni
tude
(dB
)
Tx Spectrum Rcv Spectrum0 0.5 1 1.5 2 2.5
x 106
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Frequency (Hz)
Pow
er S
pect
rum
Mag
nitu
de (
dB)
Shaped QPSK @ 128 kbps
QPSK Interference Spectrum
Normal
Survive
Survive
Normal
Survive
Survive
April 19, 2023 20© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
Adaptive Bit Loading onto OFDM carriers based on SNR
OFDM techniques where small spectral holes can be filled by one ora few carriers that fit the time - frequency hole
April 19, 2023 21© 2003 General Dynamics, All rights reserved.
Frequency
T
I
M
E
Spectral Adaptation Waveforms
OFDM Carriers Selected for Use That Fall into Available Spectrum
April 19, 2023 22© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
Adaptive Bit Loading onto OFDM carriers based on SNR
OFDM techniques where small spectral holes can be filled by one ora few carriers that fit the time - frequency hole
Interference Suppression & MultiUser Decomposition
April 19, 2023 23© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
Adaptive Bit Loading onto OFDM carriers based on SNR
OFDM techniques where small spectral holes can be filled by one ora few carriers that fit the time - frequency hole
Interference Suppression & MultiUser Decomposition
Importance of Adaptive Power ControlAD Hoc Networking (shortest hop routing w APC)
April 19, 2023 24© 2003 General Dynamics, All rights reserved.
Transmitting from A -> Z : AdHoc Networking
Node A
Node Z
April 19, 2023 25© 2003 General Dynamics, All rights reserved.
Example Spectral Awareness Etiquette Can Be Implemented on Existing SDR/Cognitive Radio (continued)
Waveform Orthogonality: Time - Freq - Code - Hop/Chirp - Spatial - Usually Involves some form of CSMA sensing for high priority user
Adaptive Frequency - find a frequency
Adaptive TDMA - find an unused time slot in between a periodic user
Spatial - Beam steering and Null Steering
Adaptive Bit Loading onto OFDM carriers based on SNR
OFDM techniques where small spectral holes can be filled by one ora few carriers that fit the time - frequency hole
Interference Suppression & MultiUser Decomposition
Importance of Adaptive Power ControlAD Hoc Networking (shortest hop routing w APC)
April 19, 2023 26© 2003 General Dynamics, All rights reserved.
Timeline: SDR’s to have Cognitive Capabilities
2003 2004 2005 2006 2007 2008
DARPA’s
Demonstrations
within 1 year
Commercial
viability
exploration &
commercial
analysis under
existing
agreements
Viability
demonstrated
for commercial
purposes
within 2 year
SDR Forum can
initiate early work
and insert into
standards bodies as
work matures
5 years for
etiquettes
to be formally
standardized
2003 2004 2005 2006 2007 2008
April 19, 2023 27© 2003 General Dynamics, All rights reserved.
In Conclusion
SDR Products and Technology are a Reality Today
SDR Standards are Actively Being Worked today by Standards Bodies and Organizations
Cognitive Radios have the Ability to Implement Protocols and Policies Beyond Traditional Communications.
New Realms of Knowledge and Information Transfer are Achievable with Cognitive/SDR Radio as the Underlying Technology Enabler
April 19, 2023 28© 2003 General Dynamics, All rights reserved.
Appendix
SCA Reference Architecture Radio Services for Application Portability SDR Forum Standardized Hardware Architecture Reference Publications
April 19, 2023 29© 2003 General Dynamics, All rights reserved.
SCA Reference Architecture
Core Framework (CF)Commercial Off-the-Shelf (COTS)
Applications
OE
Red (Non-Secure) Hardware Bus
CFServices &
Applications
CORBA ORB &Services
(Middleware)
Network Stacks & Serial Interface Services
Board Support Package (Bus Layer)
POSIX Operating System
Black (Secure) Hardware Bus
CFServices &
Applications
CORBA ORB &Services
(Middleware)
Network Stacks & Serial Interface Services
Board Support Package (Bus Layer)
POSIX Operating System
Core Framework IDL (“Logical Software Bus” via CORBA)
Non-CORBAModem
ApplicationsNon-CORBAModem API
Non-CORBASecurity
Applications
Non-CORBAHost
ApplicationsNon-CORBASecurity APIRF
ModemApplications
Link, NetworkApplications
SecurityApplications
ModemAdapter
Security
Adapter
Security
AdapterHost
AdapterHost
Applications
Modem API Link, Network API Link, Network API
Non-CORBAHost API
Link, NetworkApplications
APISecurity
April 19, 2023 30© 2003 General Dynamics, All rights reserved.
Radio Services For Application Portability
OperatingEnvironment
OperatingEnvironment
DevicesDevices
Radio SystemsApplications
Radio SystemsApplications
MiddlewareServices
MiddlewareServices
(Ext)
(Ext)
(Ext)
(Int)
(Int)
(Int)
JTR Set
RadioServices
RadioServices
(Ext)
(Int)
(Int)
WFApps
April 19, 2023 31© 2003 General Dynamics, All rights reserved.
*SDR Forum was established as an Industry Organization to address SDR technology on 1995
SDR Forum* Standardized Hardware Architecture
From Programmable Modular Communications System (PMCS) Guidance Document, 1997
RF
BB / IF
Real/
Complex
Digital/
Analog
RF
BITS
Cypher Text
Flow Contl
BITS
Plain Text
Flow ContlAux Aux Aux
Key
Fill
Representative
Information
Flow
Formats
AIR
I/O
C
RF
C C C C
I I II
CONTROL
MSG
PROCESS
& I/O
C
Routing
Common
System
Equipment
Clock/Strobe
Ref, Power
Multimedia
Voice
Data
Flow Control
Network
Ext. Ref
Remote Control/Display
User Control(HMI)
Aux: Special Purpose
I/O for Antenna Diversity
Co-site Mitigation, etc.
I: Information
BB: Baseband
C: Control/Status
SEC I/O
LINK
PROC
(Black)
I/O
C
INFOSEC
I/O
C
MODEM
I/O
C
ANTENNA
C
I
(A) (R) (M)
(C)
(S)
(R)
C
(L)
Aux
Video
April 19, 2023 32© 2003 General Dynamics, All rights reserved.
Reference Publications
Mitola, “Cognitive Radio for Flexible Mobile Multimedia Communications”,
IEEE Mobile Multimedia Conference, 1999, pp3-10
Mitola, “Future of Signal Processing - Cognitive Radio”, Keynote, IEEE
ICASSP, May 1999
Mitola, Maguire, “Cognitive Radio: Making SW Radios More Personal”,
IEEE Personal Communications, August 1999, pp13-18
Mitola, “SDR Architecture Refinement for JTRS”, Milcom 2000, pp 214-218
Mitola, “Software Radio Architecture: A Mathematical Perspective”, IEEE J
on Selected Areas in Comms, April 1999, pp 514-538
Margulies, Mitola, “Software Defined Radio: A Technical Challenge and a
Migration Strategy”, 1998, pp551-556