overview of cognitive radio systems - etsi07.12.2011 prof. dr.-ing. rüdiger kays | communication...

Prof. Dr.-Ing. Rüdiger Kays | Communication Technology Institute

Workshop Cognitive PMSE Systems

Overview of Cognitive Radio SystemsProf. Dr.-Ing. Ruediger Kays

Communication Technology Institute

[email protected]

07.12.2011CogRadio_Kays.ppt Slide 2Prof. Dr.-Ing. Rüdiger Kays | Communication Technology Institute

Contents

Overview of Cognitive Radio Systems

Motivation

Basic Concepts

Application Scenarios

Outlook


Contents


Motivation

Basic Concepts


Outlook


Motivation (1)

Radio spectrum is scarce ...

See e.g. German "Frequenznutzungsplan", a document of 674 pages...

Source: www.bundesnetzagentur.de, "Frequenznutzungsplan zum Herunterladen", Stand 31.08.2011, Download 15.11.2011


Motivation (2)

Radio spectrum is expensive ...

Price of UMTS licenses in Germany in 2000 (120 MHz @ 2 GHz, 20 years): 50.8 billion €

Price of licenses for mobile communication in Germany in 2010 (60 MHz @ 0.8 GHz): 2.96 billion €


The Race for Efficiency

Efficiency is extremely important!

The history of communication efficiency:

1948: C. E. Shannon: Information Theory

1950s/1960s Algebraic Channel Coding

1970s/1980s Convolutional Codes, Concatenated Codes

Early 1990s The "Turbo Revolution"

Late 1990s: MIMO Systems: Multiple Antennas ~ Multiple Transmission Capacity


Motivation (3)

But in reality, in any location most of the radio spectrum is free!

Measurement of power density, LS KT,TU Dortmund, 18.11.2011


Contents


Motivation

Basic Concepts


Outlook


Definition Cognitive Radio

Cognitive Radio System (ITU Definition):

A radio system employing technology that allows the system to obtain knowledge of its operational and geographical environment, established policies and its internal state; to dynamically and autonomously adjust its operational parameters and protocols according to its obtained knowledge in order to achieve predefined objectives; and to learn from the results obtained.

Definition in Rec. ITU-R SM.2152, 2009


Some related definitions...

Software Defined Radio:

A transmitter/receiver employing a universal hardware structure which can be adapted to apply different radio transmission modes (modulation, channel coding, transmission frequency) by software

SDRs are useful tools to implement cognitive radio!

RFFrontend

AD

DA

Signal Processor

Control/Software

Data out

Data in

Antenna


Some related definitions...

White Spaces:

„White spaces“ are channels within the licenced TV spectrum that are not used for TV services at a given location

Especially the TV UHFbands (470 – 790 MHz)are an interestingresource!

Measurement of power density, LS KT,TU Dortmund, 18.11.2011

EBU: „10 things you need to know about ...“, September 2011


Technical Concept

Cognitive Radio ...

...allows reuse of spectrum in white spaces

...supports dynamic spectrum access

...enables efficient transmission

...can make wireless transmission arbitrarily robust


Technical Concept

Cognitive Radio: Often means dynamic spectrumallocation, e.g. reuse of spectrum allocated to incumbent users/applications

Where does the C.R. information come from?

Spectrum sensing

Specific signalling

Data bank

By the way: A certain reuse of spectrum can also be achieved by UWB technology


How to become cognitive (1)

Spectrum Sensing

Pros:

Detection of incumbent users without the need for infrastructure – a backward compatible solution!

Detection also of other cognitive systems – self organization of spectrum reusers possible

Cons:

Implementation effort for spectrum scanner

Reliable detection of incumbents or other users of spectrum not possible in certain constellations

Detector


Problems of Spectrum Scanning



cognitiveradio

incumbent



Where is GPS???



Signalling of incumbent usage

Pros:

Adaptive solution possible

Helps to support self organisation of cognitive radios

Cons:

Signals have to be generated

Scanning required

Additional transmission effort

No backwards compatibility



Use of a data bank

Pros:

Dynamic spectrum effort for spectrum scanner avoided

Can supply reliable information about incumbent users

Cons:

Detailed information for each location has to be provided

Cognitive radio nodes need localisation

Information has to be distributed (e.g. by „cognitive channel“)

No support of cognitive network organisation


Solution

Universal solution for cognitive radio systems:Combine concepts

Different information sources should be combined, depending on application and scenario


"Ether"

Cognitive Radio Node

Universal Cognitive Radio System

AdjustableRadio

Transceiver** Adjustment of: frequency transmission power modulation scheme and FEC medium access parameters

Data

InternalData Base

SpectrumScanner

LocalCognitive

EnginePolicy andEtiquette

Cognit. Ch.Transceiver

C.R.S. DistributedData Base


Contents


Motivation

Basic Concepts


Outlook


Hierarchy

Dynamic Spectrum Usage Hierarchy

Incumbent Useralways has right of way…

Cognitive RadioSystem #1

give right of wayto incumbents…

Cognitive RadioSystem #2

Cognitive RadioSystem #n

coordination?...


Application Scenarios (1)

DVB-T@f1

DVB-T@f1

SFN 1

DVB-T@f1

DVB-T@f1

SFN 2

Cognitive Radio Systemin White Space



C-PMSE



....

....

Mobile Network



HomeGateway

Sat-Receiver

LocalServer

CognitiveMedia Network 2

CognitiveMedia Network 1

Cognitive Control Network

CognitiveHome Network


Contents


Motivation

Basic Concepts


Outlook


Current Situation

European and international standardization:

ITU-R, e.g. WRC-2012

ETSI (e.g. TC Reconfigurable Radio Systems)

IEEE (SCC 41, P1900, IEEE 802,...)

Research projects

~ 20 projects in EU FP 7, e.g. QoSMOS,...

German national projects, e.g. C-PMSE, research program „Kognitive drahtlose Kommunikationssysteme“,...

Cognitive Radio is a hot topic in research, development and standardization


Outlook

Basic idea of cognitive radio is not new

Basic concepts are known, at least in principle

Outlook

The paradigm of fixed frequency assignments has to be replaced by dynamic spectrum access to achieve

optimal usage of wireless ressources!

BUT:Complexity of wireless transmission environment

requires a lot of research on practical solutions for different scenarios!

Prof. Dr.-Ing. Rüdiger Kays | Communication Technology Institute

Thank You for Your Attention!

overview of cognitive radio systems - etsi07.12.2011 prof. dr.-ing. rüdiger kays | communication...

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