M.E Report TVWS

8/10/2019 M.E Report TVWS

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SEMINAR I REPORT ON

COGNITIVE ACCESS TO TV WHITE SPACES

SUBMITTED TO UNIVERSITY OF PUNE

FOR PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF ENGINEERINGIn

Electronics and Telecommunication

(Microwave)

By

DAMODAR Y. TAMPULA

DEPARTMENT OF ELECTRONICS AND TELECOMMUNICATION

PUNE INSTITUTE OF COMPUTER TECHNOLOGY

PUNE 43

MAY 2014


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Department of Electronics and Telecommunication EngineeringPune Institute of Computer Technology, Pune43

CERTIFICATE

This is to certify that the Seminar II Report entitled

COGNITIVE ACCESS TO TV WHITE SPACES

has been successfully completed by

DAMODAR Y. TAMPULA

towards the partial fulfillment of the degree of Master of Engineering in Electronics and

Telecommunication (Microwave)as awarded by the University of Pune, at Pune Institute of

Computer Technologyduring the academic year 2014-15.

Prof. Dr. A.P. Dhande Prof. Dr. Y. Ravinder Prof. Dr. P.T. Kulkarni

Guide HOD, E&TC Dept Principal, PICT


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ACKNOWLEDGEMENTS

All that goes with this seminar is a compromise between theoretical consideration and

practical limitation. It involves all technical and non-technical experience from various sources. I

would like to express my feeling of gratitude towards the number of people who were

instrumental and supportive in successfully making the seminar report.

I also express my profound thanks to our Prof. Dr. Y. Ravinder, H.O.D of Electronicsand Telecommunication, PICT. Whose cheerful encouragement, invaluable suggestion &

technical support of vital importance have made me to complete this seminar successfully.

I would like to pay my sincere gratitude to our seminar coordinator, Prof. Mr. P.S

Varade for her valuable suggestions and help during the seminar work that I had undertaken.

I am thankful to our Principal Prof. Dr. P. T. Kulkarniand Prof. Dr. A.P. Dhandefor the constant

encouragement and assistance they provided me.

I cannot forget to express my immense sense of thankfulness towards Rupesh Pawar, non-

teaching staffof M.E. (E&TC)department for his extended co-operation towards me. I am also thankful

to all my friends who offered their helping hands at the time of need.

Damodar Y. Tampula


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CONTENTS

Abstract IList of Acronyms Ii

List of Symbols Iv

List of Figures Vi

List of Tables Vii

1 Introduction 1-101.1 Back ground 1

1.2 Relevance 2

1.3 Literature Survey 3

1.4 Motivation 6

1.5 Scope 7

1.6 Organization of the Report 7

2 Cognitive Radio2.1

2.2

2.3

3 Spectrum Sensing in Cognitive Radio

4 Applications and Future Challenges

5 Conclusions

6 References


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ABSTRACT

Traditional wireless communication systems have fixed transmission parameters. Their

transmission frequency is fixed and the same in every location and instant of time, determined by

regulatory policies. However, the recent popularity of telecommunications and wireless

communications has increased the usage of radio spectrum exponentially. In order to supply all

the demand and improve communication parameters and Quality of Service (QoS), new

technologies need to be developed. One of the attempts to solve the problem of spectrum lack is

Cognitive Radio (CR) and TV white space (TVWS) communications. Cognitive radio is being

intensively researched as the enabling technology for license-exempt access to the so-called TV

White Spaces (TVWS), large portions of spectrum in the UHF/VHF bands which become

available on a geographical basis after digital switchover. With the digital switchover, the so

called digital dividend or white spaces appeared in the TV bands. These white spaces are unused

frequency bands within the TV transmission spectrum. TVWS communications tries to reuse

these unused channels by adapting its transmission parameters to the environment and to avoid

causing interference to the primary users of the TV bands. In this way new frequency spectrum

for unlicensed users or devices is abilitated. Both in the US, and more recently, in the UK the

regulators have given conditional endorsement to this new mode of access.


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Abbreviations and Acronyms

BER Bit Error Rate

CDMA Code Division Multiple Access

List of SymbolsV Voltage Induced

Elevation angle of arrival

List of Figures

BER Bit Error Rate


List of Tables

BER Bit Error Rate



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CHAPTER 1

Introduction

1.1 Background

Internet usage has been rising exponentially in recent years, as developments in

technology have enabled increased data rates and connectivity in many parts of the world.

This has spawned new applications which large numbers of people have been embracing

in their personal and professional lives. Many people now rely on social networking and

Internet-based video-conferencing applications to keep in touch with friends and family,

or to search for all manner of information that would previously have been unavailable or

difficult to access. Many businesses have transformed the way in which they operate,

through innovative and effective use of the Internet as a powerful tool for interacting with

customers and suppliers. Governments and not-for-profit organizations are using the

Internet to reach people and interact with them in ways which previously would not have

been possible.

Despite all of this, however, there are still large numbers of people around the

world for whom Internet access is slow and cumbersome, or even non-existent, and for

whom many of the above-mentioned applications are unavailable. This is particularly true

in rural areas, where sparse populations and rugged landscapes often make it difficult or

expensive to roll out high-speed Internet connections. Many governments and other

organizations such as the ITU and UNESCO have recognized and acknowledged that

Internet connectivity is essential for the prosperity and survival of such communities, and

have committed to various targets aimed at improving coverage and data rates.

In the UK, BT has been equipping more and more of its telephone exchanges andstreet cabinets with fibre-based broadband infrastructure. However, extending the fibre-

based infrastructure is only part of the solution. Many homes, particularly those in rural

areas, are situated several miles from their local exchanges, with no cabinets in between,

and the achievable data rates are limited by the length of the copper-wire telephone lines

from the exchange to the home.


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One potential approach to solving this local loop line length problem is to use

wireless radio links instead, and with recent developments in spectrum management

policy emerging from the switch-over of TV broadcast transmissions from analogue to

digital, interest in so-called white space spectrum is gathering pace around the world.

Rural broadband is one of the key applications that could potentially benefit from making

use of white space spectrum.

1.2 Relevance

TV White Spaces is having its strong connection with microwave as it works in

the frequency range of few mega hertz. The subjects that are related to this topic are

cognitive radio and communication technology. TVWSs are of special interest because

of two main reasons: first of all, their propagation characteristics are especially good for

wireless communications, reducing propagation losses and hence, increasing coverage.

1.3

Literature Survey

A cognitive radio consists of a cognitive engine (CE), which contains algorithms

and toolboxes for radio environment sensing, machine-learning, reasoning and decision

making, and a configurable radio platform, which could be a Software Defined Radio

(SDR), that basically does what it is told by the CE. The concept of Cognitive Radio

(CR) was first described by Mitola and Maguire as transforming radio nodes from blind

executors of predefined protocols to radio-domain-aware intelligent agents that search out

ways to deliver the services that the user wants even if that user does not know how to

obtain them. The ideal CR knows everything about the user requirements, the capability

of the radio device, the network requirements and the external environment (including theradio environment). It will plan ahead and negotiate for the best part of the spectrum to

operate in and at the best power, modulation scheme, and so forth, and manage these

resources in real time to satisfy the service and user demands. The ideal CR is currently

at the early proof-of-concept stage research, with most of the work taking place in

universities.


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A much more developed form of the CR technology is cognitive radio for

dynamic spectrum access (DSA). The aim here is to achieve device-centric interference

control and dynamic reuse of radio spectrum based on the frequency agility and

intelligence offered by cognitive radio technology. This form of CR technology is

currently being intensely researched. However, there is also already significant industry

effort towards prototyping, standardization and commercialisation of the technology.

Important industry players with active R&D efforts in cognitive radio technology include

Alcatel-Lucent, Ericsson and Motorola from the mobile equipment industry, BT and

Orange from network operators, Philips and Samsung from the consumer electronics

industry, HP and Dell from the computer industry, and Microsoft and Google from the

Internet/software industry. Dynamic spectrum access may take place in several ways:

between a licensed primary system and a license-exempt secondary system, for example,

secondary spectrum access to digital TV or military spectrum, within the same primary

system, for example, micro-macro sharing of licensed spectrum in 3G/LTE femto-cells,

and finally among two primary systems, for example, real-time leasing and trading of

spectrum between two cellular operators.

The first form of dynamic spectrum access is arguably the most disruptive

application of the CR technology, as it enables license-exempt users (end-user devices

and base stations) to act as spectrum scavengers (Carlson and Telcordia have made DSA

technology devices). They can identify unused portions of licensed spectrum (also called

spectrum holes or White Spaces) and make opportunistic use of this spectrum for their

connectivity at times and/or locations where they are not used. Allowing the operation of

such scavenger promises to greatly increase the efficiency of spectrum usage by

preventing exclusively licensed spectrum from being wasted due to low spatial or

temporal usage. Mainly for this reason licensed-exempt cognitive access to certain

licensed bands is being keenly promoted by the US regulator, the (Federal

Communication Commission) FCC, and more recently also by Ofcom. The rationale is to

maximize the usage of licensed spectrum through secondary access by cognitive radios

and, at the same time, promote rapid introduction of new wireless technologies and

services without the need for setting aside any new spectrum for this purpose. Most

mobile operators see this form of cognitive access as highly disruptive to their current


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business model.

In the longer term (35 years), we expect that dynamic spectrum access based on

cognitive radio will go far beyond opportunistic spectrum access only. As a result of the

current trends in spectrum liberalisation, including the availability of licensed spectrum

for real-time trading, cognitive devices may be able to access a portfolio of different

types of spectrum for their connectivity. This spectrum portfolio may include several

different type of spectrum: licensed spectrum (e.g., in cellular bands), licensed-exempt

spectrum (in the ISM bands), as well as spectrum that is, acquired in real-time, either

through leasing or on a secondary basis. Devices with cognitive functionality will be able

to dynamically change their operating spectrum within this portfolio, accessing the best

available spectrum on a just-in-time basis. This may happen either upon instruction

from a base station or autonomously by devices themselves. Depending on the user and

network requirements devices may pool together and use several spectrum fragments and

vacate some or all of them when they are no longer required or when other more suitable

ones become available. These requirements may depend on context, application and

location and can include price, Quality of Service (QoS), and energy saving.

To date both in the UK and US regulators have committed to licence-exempt

cognitive access to the so-called TV White Spaces (TVWS). The TVWS spectrum

comprises large portions of the UHF/VHF spectrum that become available on a

geographical basis for cognitive access as a result of the switchover from analogue to

digital TV. The total capacity associated with TVWS is significant. According to

modelling studies commissioned by Ofcom over 50% of locations in the UK are likely to

have more that 150MHz of interleaved spectrum and that even at 90% of locations

around 100MHz of interleaved spectrum might be available for cognitive access [10]. In

addition to TVWS, the defence spectrum may provide another significant capacity

opportunity for license-exempt cognitive access. For example, around 30% of spectrum

below 15GHz is allocated to Defence in the UK. The UK (Ministry of Defence) MoD

had until the late 1990's access to spectrum at no or a low cost. However, following the

Cave Audit, the Government has committed to releasing a significant proportion of the

MOD's spectrum between 2008 and 2010. Results from a 2008 study by PA consulting

(commissioned jointly by MoD and Ofcom) suggest that there is significant scope for


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license-exempt use of the released spectrum using cognitive radio technology, both on a

spatial and a temporal basis. For example, low power cognitive devices could potentially

share with radar if the radar sweep can be detected and the transmission of the cognitive

device can be timed to avoid interference.

1.4 Motivation

Internet usage has been rising exponentially in recent years, as developments in

technology have enabled increased data rates and connectivity in many parts of the world.

This has spawned new applications which large numbers of people have been embracing

in their personal and professional lives that would previously have been unavailable or

difficult to access.

Recent developments in spectrum management policy emerging from the switch-

over of TV broadcast transmissions from analogue to digital, interest in so-called white

space spectrum is gathering pace around the world. Rural broadband is one of the key

applications that should potentially benefit from making use of white space spectrum.

As well as assessing the technical ability of the network to provide broadband

access, a further aim was to investigate the extent to which the white space broadband

transmissions would be able to co-exist with Digital Terrestrial Television (DTT)

transmissions without adversely affecting TV reception, and to what extent theoretical

predictions would match measurements made in the field.

1.5 Scope

This paper aims to review the state-of-the-art in technology, regulation, and

standardization of cognitive radio access to TVWS. It also examines the spectrum

opportunity, potential business applications, and some of the open research challenges

associated with this new form of access.

A number of rural communities have complained about the poor broadband

performance they receive from currently available commercial services. Their experience

is not unusual in other rural areas around the UK and elsewhere in Europe. The key


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attraction of TV white spaces in this application is the enhanced range which lower

frequencies enable (compared to the higher frequency bands traditionally used for

wireless broadband access). This extended range translates into fewer base stations being

required to cover a given area and, hence, lower coverage costs. An additional advantage

of licence-exempt access, which can be enabled through the use of geo-location

databases, is that rural communities would be free to provide their own wireless

networks.

1.6 Organization of Report

Contents of each chapter and report organizations is to be included briefly.


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CHAPTER 2

What is TV White Spaces?

2.1 Introduction

White Spaces are portions of radio spectrum which are not used by existing licensees at

all times or in all locations. Figure 1-1 illustrates the concept, showing unused white spaces

between licensed transmissions. With demand for wireless connectivity increasing, the

exploitation of white space is an attractive way of making more efficient use of radio spectrum.

In many countries, analogue television broadcasts are being switched off and replaced bymore spectrally efficient digital television transmissions, and the white spaces that exist in the

UHF TV band (470 MHz - 790 MHz in ITU Region 1) have good propagation and building

penetration characteristics.1 This potentially makes them suitable for use in rural broadband

applications, where transmission links may be several kilometres in length and may involve

challenging terrain such as hills, foliage, and water.

Figure1.1: TV White Spaces

Allowing licence-exempt devices to interleave their transmissions with those of licensed

users does, however, present challenges in ensuring that such unlicensed transmissions will not

adversely interfere with the licensed transmissions. The approaches adopted by the FCC and


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Ofcom differ slightly, but both involve the use of a regulator-approved database which White

Space Devices (WSDs) will need to consult before being allowed to access the spectrum.

Broadcast television services operate in licensed channels in the VHF and UHF portions

of the radio spectrum. The regulatory rules in most countries prohibit the use of unlicensed

devices in TV bands, with the exception of remote control, medical telemetry devices, and

wireless microphones. In most developed countries regulators are currently in the process of

requiring TV stations to convert from analogue to digital transmission. This Digital Switchover

(DSO) was completed in the US in June 2009, and is expected to be completed in the UK by

2012. A similar switchover process is also underway or being planned (or is already completed)

in the rest of the EU and many other countries around the world. After Digital Switchover a

portion of TV analogue channels become entirely vacant due to the higher spectrum efficiency of

digital TV (DTV). These cleared channels will then be reallocated by regulators to other services

through auctions.

In addition to cleared spectrum, after the DTV transition there will be typically a number

of TV channels in a given geographic area that are not being used by DTV stations, because such

stations would not be able to operate without causing interference to co-channel or adjacent

channel stations. However, a transmitter operating on such a locally vacant TV channel at a

much lower power level would not need a great (physical) separation from co-channel and

adjacent channel TV stations to avoid causing interference. Low power devices can therefore

operate on vacant channels in locations that could not be used by TV stations due to interference

planning. These vacant TV channels are known as TV White Spaces or Interleaved Spectrum in

the language of the UK regulator.

2.2 Sub Heading

2.2.1

Sub-Sub Heading

2.3 Figures

Figures are expected to be drawn using drawing software, imported from other simulations


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software in original. They should not be just scan, copy paste from the literature. Figures has to

be indexed and explained clearly as given in the followed.

x

y

z

Element lat( dx, d

y,d

z)

Direction of Plane Wave

Propagation

Fig: 2.1. Basic Antenna Array Geometry

Further, it is assumed that the signal )(ts is incident on an array of L isotropic elements shown

in Fig. 2.1, from a direction with, being the elevation and azimuth angles respectively.

Fig. 2.2 BER Performance of Basic Linear Array

N=2,=[150-30

060

0-70

080

0],=0.06,NI=15,M=5

(Co-ordinates in the block indicate X=SNR, Y=BER )

0 2 4 6 8 10 12 14 16 18 20-18

-16

-14

-12

-10

-8

-6

-4

-2

0

X: 15

Y: -9.907

X: 15

Y: -7.662

SNR(dB)

log10(BER)

BER-MMSE-BASIC

BER-MBER-BASIC


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All the graphs should be clearly visible with title, labels of each axis, legends, and line

markers as shown in Fig. 2.2 above. Graphs, results must be clearly interpreted in the text by

explaining the numerical, its significance and inferences as followed.BER performance of the

basic linear array of isotropic elements is carried out for various SNR and plotted in Fig. 2.2.

Here, the algorithmic parameter is set to 0.06 and the initial weight vector to [0.1+0i0.1+0i].

MBER solution converged to a lesser BER after 15 iterations that compared with MMSE

solution. At SNR=15, the BER is found to be 10-7.662

and the weight vector to be

[0.0228+0.0056i 0.0197+0.0127i] by MMSE approach, whereas, by MBER approach, BER is

10-9.907

and weight vector is [0.48000.7456+0.4623i].

2.4

Equations

All the equations must be typed either in MS equation editor or any other compatible

equation editors. Equations scanned, copied are not acceptable. Please refer the following

sample equation and follow the same uniformly throughout the report. All the symbols must be

explained when they appear for the first time. Every equation must be explained clearly. For

instance Eqn. (2.1) indicates that the equation number one in second chapter.

ww

w

ww

wH

qRRsbN

q H

sb

R

yy

Nyp

2

2

,

2 2

)(exp

1 2

11)1/;(

(2.1)

2.5 Tables

Table 2.1

Crossed dipole impedance matrix


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CHAPTER 3

Title of the Chapter 3


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CHAPTER 4

Applications and Future Challenges


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ReferencesBooks:

[1]

Constantine A. Balanis, Antenna Theory: Analysis and Design, 2ndEdition; John Wiley

Sons Inc. New York, 2001,pp12-130

Transaction/Journals:

Amir Ghasemi, Spectrum Sensing in Cognitive Radio Networks: Requirements,

Challenges and Design Trade-offs, IEEE Communications Magazine, April 2008.

International/National Conference Proceedings:

Moshe T. Masonta, David Johnson and Mjumo Mzyece,The White Space Opportunityin Southern Africa: Measurements with Meraka Cognitive Radio Platform, Tshwane

University of Technology, Pretoria, South Africa, 2011

Evanny Obregon, Lei Shi, Javier Ferrer, and Jens Zander,Experimental Verification of

Indoor TV White Space Opportunity Prediction Model Cognitive Radio Oriented

Wireless Networks & Communications(CROWNCOM), June, 2010

Cyrus Gerami, Narayan Mandayam, Larry Greenstein, Backhauling in TV White

Spaces, Global Telecommunication Conference(GLOBECOM 2010).

Standards/Patents:

[2] G.Brandli and M. Dick, Alternating current fed power supply, U.S.Patent 4 084 217,

Nov.4,1978

Technical Reports:

Maziar Nekovee, A Survey of Cognitive Radio Access to TV White Spaces,International Journal of Digital Multimedia Broadcasting, Volume 2010 (2010), Article

ID 236568, Accepted 6 April 2010

Website:


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[3] M. Duncan. Engineering Concepts on Ice. Internet: www.iceengg.edu/staff.html, Oct.

25, 2000 [Nov. 29, 2003].

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