Wimpie van den Berg - AOC Aardvark Roostaardvarkaoc.co.za/wp-content/Conf_Aug_2009/Wimpie van den... · 2014-10-31 · SDR Technology Technology fundamentals: • Digital Signal Processors

Cognitive Radio

Intelligence & Security Solutions

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Intelligence & Security Solutions

Presented by: W van den Berg

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Contents

• RF spectrum today and future

• Cognitive radio

• The SDR advantage

• Cognition Cycle

• Spectrum awareness etiquettep q

• Conclusion

• Summary

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The RF spectrum

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Cognitive Radio is Built on SDR

Cognition (Noun):

Cognition is the mental process involved in knowing, g p g,learning, and understanding things.

Cognitive Radio:Cognitive Radio:

Cognitive Radio is an intelligent wireless communication system that is aware of it’s surrounding environment and usessystem that is aware of it s surrounding environment and uses

the methodology of understanding-by-building to learn from the environment and adapt its internal states to statistical

variations in the incoming RF stimuli by making correspondingvariations in the incoming RF stimuli by making corresponding changes in certain operating parameters in real-time.

-S Haykin “Cognitive Radio ”

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-S. Haykin, Cognitive Radio,

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Cognitive Radio - Built on SDR

Cognitive radio is a paradigm for wireless communication in whichCognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users.

This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum user behavior and network statefrequency spectrum, user behavior and network state.

-Wikipedia, “Cognitive Radio”p , g

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Definition of SDR

“We view software defined radios as the result of anevolutionary process from purely hardware-basedequipment to fully software-based equipment In thisequipment to fully software based equipment. In thisregard, the process can be roughly described in threestages”

1. Hardware driven radios: Transmit frequencies, modulation type and other radio frequency (RF) parameters are determined by hardware and cannot be parameters are determined by hardware and cannot be changed without hardware changes.

2. Digital radios: A digital radio performs part of the i l i t i i di it ll b t i t signal processing or transmission digitally, but is not

programmable in the field

3. Software Defined Radios:. All functions, modes and

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applications can be configured and reconfigured by software.

Definition of SDR - Continued

SDR Forum also add’s:

4. SW defines all waveform properties, cryptography and

applications, is re-programmable, and may be

upgraded in the field with new capabilitiesupgraded in the field with new capabilities

Importance of Standards (APIs)

5. HW Interfaces, RF services, Operating Environment,

Application to Radio Interfaces

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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 • 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

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SDR Standardized Architecture

• FDMA, TDMA, CDMA, TDD

Architecture supports Both Current and Future Applications

• 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, ….

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Building the Cognitive Radio using SDR Technologygy

• SDR drives the Cognitive Radio concept that will provide h l h l h lthe spectral awareness technology supporting the Spectral

Use initiatives

• SDR is a proven, flexible, COTS technology platform

• SDR Technology is in Production and Available Now

New

Announcements

Coming

Soon

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Cognitive Radio Means “Smart” and “Alert”

• It knows where it is• It knows where it is

• It knows what services are available, for example, it can identify then use empty identify then use empty spectrum to communicate more efficiently

• It knows what services interest h d k hthe user, and knows how to

find them

• It knows the current degree of needs and future likelihood of needs and future likelihood of needs of its user

• Learns and recognizes usage patterns from the userpatterns from the user

• Applies “Model Based Reasoning” about user needs, local content, environmental

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context

How Does a Cognitive Radio Get So Smart?

The Cognition Cycle

OrientEstablish Priority

Normal

The Cognition Cycle

Infer on Context Hierarchy

Plan Generate Alternatives

(Program Generation)

Evaluate Alternatives

Pre-process

Parse

ImmediateUrgent

Register to Current Time

Decide

Learn

Save Global

ObserveReceive a Message

Read Buttons

New

States

Alternate Resources

Initiate Process(es)Act

Save Global

States

Read Buttons

Prior

StatesOutside( )

(Isochronism Is Key)

Set DisplaySend a MessageWorld

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Mitola, “Cognitive Radio for Flexible Mobile Multimedia Communications”, IEEE Mobile Multimedia Conference, 1999, pp3-10

An Analogy: Cognitive Radio and a Car Driver

Cognitive Radio’s capabilities:

• Senses, and is aware of, its

Car Driver’s capabilities:

• Senses, and is aware of, itsSenses, and is aware of, its operational environment and its capabilities

• Can dynamically and

Senses, and is aware of, its operational environment and its capabilities

• Can dynamically and autonomously y yautonomously adjust its radio operating parameters accordingly

• Learns from previous

y y yadjust the driving operation accordingly

•Learns from previous experiencespexperiences

• Deals with situations not planned at the initial time of

•Learns from previous experiences

• Deals with situations not planned at the initial time of learning to drive

design

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Spectrum awareness Etiquette

Existing SDR / Cognitive Radio for implementationExisting SDR / Cognitive Radio for implementation

• Infrastructure Based Approachesas uc u e ased pp oac es

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 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

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Example Spectral Awareness Etiquette

• Cognitive Radios can adopt new etiquettes for new standards

• Possible Demonstrations using existing SDRs• Possible Demonstrations using existing SDRsSpectrum rental transactionsSpectral Availability (Borrow) BeaconLocal Spectrum Utilization Database Server Local Spectrum Utilization Database Server (time, freq, code, space, power, modulation)

• Waveform Orthogonality: Time - Freq - Code - Hop/Chirp -Spatial - Usually Involves some form of sensing for high priority userpriority user

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Spectral Awareness Etiquette

SDR Finds Frequency - Time Opportunities

Deployed waveforms

Existing SignalsExisting Signals

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Detailed Signal Parameters


Adaptive Frequency - find a frequency

Adaptive TDMA - find an unused time slot in between a periodic userp p

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Opportunities for Spectral Reuse Amongst Periodic Signals

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Adaptive TDMA - find an unused time slot in between a periodic userp p

Spatial - Beam steering and Null Steering

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Time - Frequency - Space

Each Domain has Opportunities for Spectral Reuse Spectral Awareness Etiquette

Transmitter forms Beam Toward Intended Recipient

Receiver forms Null Toward Interference Sources

R1,R4

T1

,

T2

Interfering

T3

R3,T4

Signal Placed

In Null

R3

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Adaptive TDMA - find an unused time slot in between a periodic userAdaptive TDMA find an unused time slot in between a periodic user


Adaptive Bit Loading onto OFDM carriers based on SNRp g

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OFDM Interference Avoidance

QPSK I t f S t

-60

-50

-40

-30

-20

-10

0

Spe

ctru

m M

agni

tude

(dB

)

Shaped QPSK @ 128 kbps

QPSK Interference Spectrum

0

B)

-20

dB)

Tx Spectrum Rcv Spectrum0 0.5 1 1.5 2 2.5x 10 6

-100

-90

-80

-70

60

Frequency (Hz)

Pow

er S

-80

-60

-40

-20

ower

Spe

ctru

m M

agni

tude

(dB

-120

-100

-80

-60

-40

Pow

er S

pect

rum

Mag

nitu

de (d

1

2

3

00.5

11.5

22.5

x 106

-100

Transmission NumberFrequency (Hz)

Po

1

2

3

00.5

11.5

22.5

x 106

-140

Transmission NumberFrequency (Hz)

P

Normal

Survive

Survive

Normal

Survive

Survive

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Adaptive TDMA - find an unused time slot in between a periodic user


Adaptive Bit Loading onto OFDM carriers based on SNR

OFDM techniques where small spectral holes can be filled by one or

a few carriers that fit the time - frequency hole

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Spectral Adaptation WaveformsSpectral Adaptation Waveforms

T

Frequency

T

I

M

E

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a few carriers that fit the time - frequency holeInterference Suppression & MultiUser DecompositionInterference Suppression & MultiUser Decomposition

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Importance of Adaptive Power Control

AD Hoc Networking (shortest hop routing w APC)

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T itti f A Z AdH N t ki


Transmitting from A -> Z : AdHoc NetworkingNode Z

Node A

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Importance of Adaptive Power Control

Page 29AD Hoc Networking (shortest hop routing w APC)

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Timeline: SDR to have Cognitive Capabilities

2003 2004 2005 2006 2007 2008 12

C i l5 - 7 years for

2003 2004 2005 2006 2007 2008 - 12

DARPA’s

Demonstrations

Commercial

viability

exploration &

commercial

Viability

demonstrated

for commercial SDR Forum can

etiquettes

to be formally

standardized

within 1 yearcommercial

analysis under

existing

agreements

purposes

within 2 year

initiate early work

and insert into

standards bodies as

2003 2004 2005 2006 2007 2008 - 12

gwork matures

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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. y

• New Realms of Knowledge and Information Transfer are Achievable with Cognitive/SDR Radio as the Underlying Technology EnablerTechnology Enabler

• Challenges:

Spectrum policySpectrum policy

Spectrum sensing

Spectrum sharing

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Waveforms

The future is only limited by ourThe future is only limited by our

Dreams and minds

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Summary

Reference Publications

• Mitola, “Cognitive Radio for Flexible Mobile Multimedia gCommunications”, 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

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g gand a Migration Strategy”, 1998, pp551-556

Contact us at:

• Email: [email protected]

• Phone: +27 12 421 6213

Web ge co a

Thank you!• Web: www.gew.co.za

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Wimpie van den Berg - AOC Aardvark Roostaardvarkaoc.co.za/wp-content/Conf_Aug_2009/Wimpie van den... · 2014-10-31 · SDR Technology Technology fundamentals: • Digital Signal Processors