Interference Analysis (eBook)

Modelling Radio Systems for Spectrum Management

John Pahl (Autor)

eBook Download: EPUB

2016
John Wiley & Sons (Verlag)
9781119065326 (ISBN)

Infos

The book describes how interference can be managed so that radio systems co-exist, without harmful mutual effects, within a finite amount of spectrum.  This is timely in view of the increasing proliferation of wireless systems.  It covers both the processes, such as regional or international coordination, as well as the engineering principles.  Written by an author with extensive experience in the industry, it describes in detail the main methodologies for calculating or computing the interference between radio systems of the same type, and also between radio systems of different types

John Andrew Pahl, Director, Transfinite Systems Ltd, UK
Pahl has worked in the field of interference analysis since the late 1980s and is director of a company specializing in this field. The company undertakes consultancy work, and has clients involved in many different types of radio systems from mobile to satellite to fixed, exposing the author to a wider range of technologies and methodologies than many in the field. He receives regular invitations to Chair international conferences, and is a recognized world expert in Equivalent Power Flux Density (EPFD) analysis under Article 22 of the Radio Regulations. He is an experienced trainer and writer, having given dozens of training courses for his company and helping his clients understand the issues involved in interference analysis. Pahl is ideally placed, therefore, to write this book which is aimed at the professional market he inhabits.

Inhalt

FOREWORD 7

PREFACE 8

CHAPTER 1. INTRODUCTION 9

1.1 Motivations and Target Audience 9

1.2 Book Structure 10

1.3 Chapter Structure and Additional Resources 11

1.4 Case Study: How to Observe Interference 11

CHAPTER 2. MOTIVATIONS 13

2.1 Why Undertake Interference Analysis? 13

2.2 Drivers of Change 14

2.3 The Regulatory Framework 15

2.4 International Regulations 16

2.5 Updating the Radio Regulations and Recommendations 32

2.6 Meetings and Presenting Results 35

2.7 National Regulators 38

2.8 Regional and Industry Organisations 39

2.9 Frequency Assignment and Planning 41

2.10 Coordination 44

2.11 Types of Interference Analysis 46

2.12 Further Reading and Next Steps 46

CHAPTER 3. FUNDAMENTAL CONCEPTS 47

3.1 Radio Communication Systems 47

3.2 Radio Waves and Decibels 50

3.3 The Power Calculation 53

3.4 Carrier Types and Modulation 56

3.5 Multiple Access Methods 69

3.6 Noise Temperature and Reference Points 79

3.7 Antennas 85

3.8 Geometry and Dynamics 103

3.9 Calculation of Angles 122

3.10 Statistics and Distributions 128

3.11 Link Budgets and Metrics 135

3.12 Spectrum Efficiency and Requirements 138

3.13 Worked Example 141

3.14 Further Reading and Next Steps 143

CHAPTER 4. PROPAGATION MODELS 144

4.1 Overview 144

4.2 The Propagation Environment 147

4.3 Terrestrial Propagation Models 158

4.4 Earth to Space Propagation Models 198

4.5 P.528: Aeronautical Propagation Model 204

4.6 Additional Attenuations 205

4.7 Radio Path Geometry 207

4.8 Percentages of Time and Correlation 208

4.9 Selection of Propagation Model 212

4.10 Further Reading and Next Steps 216

CHAPTER 5. THE INTERFERENCE CALCULATION 217

5.1 Bandwidths and Domains 217

5.2 Bandwidth Adjustment Factor 221

5.3 Spectrum Masks, Ratios and Guard Bands 223

5.4 Polarization 249

5.5 Adaptive Systems: Frequency, Power and Modulation 253

5.6 End to End Performance 259

5.7 Modelling Deployment and Traffic 261

5.8 Link Design and Margin 271

5.9 Interference Apportionment and Thresholds 275

5.10 Types of Interference Thresholds 285

5.11 Interference Mitigation 306

5.12 Further Reading and Next Steps 317

CHAPTER 6. INTERFERENCE ANALYSIS METHODOLOGIES 318

6.1 Methodologies and Studies 318

6.2 Example Scenarios 320

6.3 Static Analysis 328

6.4 Input Variation Analysis 335

6.5 Area and Boundary Analysis 339

6.6 Minimum Coupling Loss and Required Separation Distance 345

6.7 Analytic Analysis 348

6.8 Dynamic Analysis 354

6.9 Monte Carlo Analysis 364

6.10 Area and Two Stage Monte Carlo 386

6.11 Probabilistic Analysis 392

6.12 Selection of Methodology 393

6.13 Study Projects and Working Methods 396

6.14 Further Reading and Next Steps 398

CHAPTER 7. SPECIFIC ALGORITHMS AND SERVICES 399

7.1 Fixed Service Planning 400

7.2 Private Mobile Radio 407

7.3 Broadcasting 421

7.4 Earth Station Coordination 433

7.5 GSO Satellite Coordination 440

7.6 EPFD and Rec. ITU-R S.1503 456

7.7 The Radar Equation 471

7.8 N-Systems Methodology 475

7.9 Generic Radio Modelling Tool 482

7.10 White Space Devices 488

7.11 Final Thoughts 500

CHAPTER 8. REFERENCES 501

CHAPTER 9. ACRONYMS, ABBREVIATIONS AND SYMBOLS 511

CHAPTER 10. INDEX 519

Rezensionen

Interference analysis is fundamental to spectrum management and this book provides a comprehensive and detailed guide to this subject. The author is an expert who has chaired ITU-R meetings and contributed to many ITU-R Recommendations. The book builds from the motivations for interference analysis, including national and international regulatory regimes, all the way to sophisticated Monte Carlo analysis and descriptions of how to model specific services and their associated algorithms. It covers a wide range of systems and services, including Wi-Fi, fixed links, private mobile radio (PMR), 2G, 3G, 4G, broadcasting, radar, white space, ultra-wideband and programme making and special events plus science, navigation, maritime, aeronautical and satellite systems, including both GSO and non-GSO.

The book describes fundamental concepts such as the link budget, carrier types, access methods, noise calculations, antennas, dynamics, statistics and propagation models and then builds up to details of the interference calculation and interference analysis methodologies. In particular, the book describes how to convolve transmit and receive spectrum masks, construct link budgets with an associated interference margin and use them to derive thresholds, including apportionment. Alternative interference metrics are described together with methods to mitigate against interference.

The book is essential for both those new or experienced in the field, to help understand and advance technical studies for system design, frequency assignment, coordination or regulatory analysis.

Dr Haim Mazar, Israel

Textauszug

1
Introduction

All radio systems share the same electromagnetic spectrum. This means that each radio receiver is detecting not just its wanted signal but all other signals transmitted at the same time anywhere – not just on this planet, but anywhere, even in space. If there are aliens out there using radio technology, their signals will also be added to the mix.

But it is rare for us to experience interference into our communication devices – such as radios, televisions and mobile phones – on a day-to-day basis. This is not an accident but the result of years of hard work by radio engineers and regulators to ensure that the signals from one user of the radio spectrum do not degrade significantly another user or, as is more commonly described, cause interference into the receiver.

Interference analysis is the study of how one or more radio systems can degrade the operation of other users of the radio system. It includes techniques to predict the level of interference and whether that could be tolerated or would represent a serious degradation, otherwise known as harmful interference.

This subject builds upon other specialist topics, such as antenna design and propagation, and often involves analysis of scenarios that includes different types of radio system. Therefore when undertaking interference analysis, it is necessary to become familiar with a wide range of other topics plus mathematical modelling techniques, statistics and geometry.

The objective of this book is to be useful to anyone involved in interference analysis – to help understand the various techniques and methodologies that could be used in studies. The approach in this book is to give an integrated view of interference analysis, describing all the key issues necessary to generate results. It will consider different types of interference and metrics to determine whether the interference could be accepted or would be considered harmful.

1.1 Motivations and Target Audience

There are different motivations for undertaking interference analysis, in particular:

• System design: to optimise a radio system to allow the maximum service while reducing interference, whether within the system, to other systems or from other systems
• Regulatory: to identify what radio services can share with other radio services and hence allow them to be included in the tables of allocation used by spectrum managers
• Frequency assignment: to determine if a regulator can issue a new licence (e.g. to a taxi company) without it causing or suffering harmful interference
• Coordination: during discussions between two radio system operators (or countries) to identify ways to protect each other’s receivers from the other’s transmissions.

This book is aimed at anyone with an interest in interference between radio systems, in particular those operating with frequency above about 30 MHz. This could include:

• A member of a national spectrum management regulator is meeting with representatives from a neighbouring country to make a bilateral agreement that can be used to protect each country from interference. What would be a suitable interference threshold level to agree and how would it be checked/calculated?
• A mobile operator’s spectrum management team wants to open up new bands for next generation broadband. They need to argue at an international level, in particular at the International Telecommunication Union, that such an introduction would be the most effective use of the scarce radio spectrum.
• A satellite operator is meeting with another satellite operator to ensure that neither causes harmful interference into the other. At the coordination meeting they will agree the signal levels that can be transmitted on each satellite beam: what should they propose and how can they check the suggestions from the other company?
• A consultant is working for the aeronautical community to help identify bands that can be used to provide broadband services to commercial aircraft. They must undertake sharing scenarios and convince regional bodies, such as Europe and North America, that these will be safe.
• The national spectrum management regulator receives a request for a new licence to provide a service (e.g. land mobile or fixed link). How can they check it would not cause or suffer interference to/from existing licensees?
• Students studying electrical engineering, communication systems or simulation techniques, who wish to learn more about interference analysis and modelling radio systems, together with academics undertaking research on these topics.

1.2 Book Structure

The book is structured as follows:

• Chapter 2. Motivations: considering the reasons why people undertake interference analysis, including the regulatory framework, international organisations and working methods.
• Chapter 3. Fundamental Concepts: covers the basics of radio engineering, including modulations, access methods, antennas, noise calculations, the underlying geometry and dynamics, link budgets and their attributes.
• Chapter 4. Propagation Models: the model of how radio waves propagate between transmitter and receiver (whether wanted or interfering) can make a huge difference to the results, so it is important to understand the various propagation models that are available and when they should be used.
• Chapter 5. The Interference Calculation: how to use the concepts above to calculate interference, including aggregation effects, polarisation adjustment, co-frequency vs. non-co-frequency, thresholds, interference apportionment and possible mitigation techniques.
• Chapter 6. Interference Analysis Methodologies: the complexity of the analysis can vary from static analysis, where the answer is a single number, to dynamic, Monte Carlo and area analysis, each with strengths and weaknesses. To help explain each of the different approaches, worked examples will show how they can be used to analyse sharing between:
  • A deployment of base stations of a Long Term Evolution (LTE) network into satellite Earth stations in parts of C-band
  • A non-GSO mobile-satellite service (MSS) system and point-to-point fixed links.
• Chapter 7. Specific Algorithms and Services: some services and sharing scenarios have well-defined publically available algorithms to calculate performance including interference analysis. Examples would be broadcasting, private mobile radio, white space and satellite coordination.

1.3 Chapter Structure and Additional Resources

Each chapter is structured starting with a summary of its contents and ending with pointers for further reading. Within each chapter are examples of the calculations involved to, as far as possible, allow the reader to reproduce the analysis undertaken. There are also available additional resources to increase understanding of the topics being analysed. These include:

• Spreadsheets to support standard calculations, such as link budgets and geometry conversions
• Example simulation files configured for the scenario under discussion.

These can be found by following the link on the Wiley web site page for this book.

Wherever possible the international system of units are used for all calculations.

1.4 Case Study: How to Observe Interference

It is generally hard to accidentally create interference between different types of consumer radio systems. It should be noted that deliberately causing interference into another’s radio system is considered a criminal offence in most legal systems and so should not be attempted. But you could try observe the impact of interference into one of your own radio receivers in a licence exempt band and see if you can detect any change in behaviour.

A good frequency band to experiment with is the one used by Wi-Fi at around 2.4 GHz as this has a range of different uses including microwave ovens. These are shielded to reduce emissions outside the device but there is usually some leakage that can be used as a source of interference into communications equipment. In particular, this can lead to issues for sensitive services such as radio astronomy. In 2015 the Parkes Radio Telescope in Australia investigated unusual signals it classed as ‘perytons’ and the source was discovered to be an on-site microwave oven emitting pulses at 1.4 and 2.4 GHz (Petroff et al., 2015).

For example, consider the two set-ups in Figure 1.1 where a smartphone was configured with an application to test the speed of the broadband link accessed via a Wi-Fi connection. Initially in case A the smartphone was positioned 0.5 m from a microwave oven and about 5 m from the access point. The Wi-Fi access point was configured to use the 2.4 GHz band rather than other frequencies (e.g. those around 5 GHz).

Figure 1.1 Domestic test set-up for detecting interference

The throughput was tested twice for each of the cases when the oven is on or off with results as in Table 1.1.

Table 1.1 Results of tests for case A: Smartphone by microwave oven

Microwave oven

Off

On

Test 1

9.38 Mbps

0.72 Mbps

Test 2

9.40...

Produkt-Details

• Erscheint lt. Verlag: 13.4.2016
• Sprache: englisch
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Nachrichtentechnik
• Schlagworte: Antennas & Propagation • Drahtlose Kommunikation • Electrical & Electronics Engineering • Elektrotechnik u. Elektronik • Interference • Mikrowellen- u. Hochfrequenztechnik u. Theorie • Mobile & Wireless Communications • Modelling Systems and Antennas • Radio Communications • Radio Systems • RF / Microwave Theory & Techniques • Sende- u. Empfangseinrichtungen • Spectrum analysis
• ISBN-13: 9781119065326 / 9781119065326