Communicating Embedded Systems E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 438

Veröffentlichungsjahr: 2013

Beschreibung

Embedded systems are becoming increasingly complex, and as they become more widespread, more capable, and more densely integrated in everyday consumer, household, industrial, and more specialized products, the design and use in applications of such systems requires knowledge of several different disciplines such as electronics, data processing, telecommunications, and networks. Without detailing all aspects of electronics, circuit design, and computer architecture related to the design of embedded systems, this book, written by expert specialists in electronics, data processing and telecommunications and networks, gives important insights into the communication techniques and problems encountered in embedded systems. The book focuses on applications in the area of telecommunications and networks because the vast majority of embedded systems are deployed in communications systems and equipment, and it therefore makes an excellent field-wide case study.

Leseprobe

Table of Contents

General Introduction

Chapter 1. Introduction to Embedded Systems

1.1. Introduction

1.2. Embedded system: a definition

1.3. Properties of an embedded system

1.4. The significance of Moore’s Law

1.5. Embedded systems and the system on silicon

1.6. Embedded systems and communications

1.7. Embedded systems and security

1.8. Embedded systems and time constraints

1.9. Embedded systems and free software

1.10. Embedded systems and their design

1.11. An example of multimedia embedded system design

1.12. Conclusion

1.13. Bibliography

Chapter 2. Quality-of-Service Routing in Mobile Ad Hoc Networks

2.1. Introduction

2.2. Mobile ad hoc networks: concepts, characteristics, challenges

2.3. QoS routing: general considerations

2.4. Best-effort routing protocols in MANETs

2.5. QoS routing in MANETs

2.6. Conclusion

2.7. Bibliography

Chapter 3. Self-Management of Ad Hoc Sensor Networks

3.1. Introduction

3.2. Wireless sensor networks

3.3. Autonomic sensor networks

3.4. An example of self-configuration

3.5. Conclusion

3.6. Bibliography

Chapter 4. RFID Technology

4.1. Introduction

4.2. Automatic identification systems

4.3. The components of an RFID system

4.4. The different types of RFID systems

4.5. RF ranges

4.6. Information security

4.7. Standards in force

4.8. Examples of implementations

4.9. Conclusion

4.10. Bibliography

Chapter 5. Hardware Security in Embedded Systems

5.1. Introduction

5.2. Embedded systems and their security issues

5.3. Security of the system and its data

5.4. Secured hardware architectures for embedded systems

5.5. Conclusion

5.6. Bibliography

Chapter 6. Communications Security in Embedded Systems

6.1. Introduction

6.2. Communications security

6.3. Communications security in embedded systems

6.4. Conclusion

6.5. Bibliography

Chapter 7. Cross-Layer Adaptation for Multimedia Services in 802.11-Type Embedded Communications Systems

7.1. Introduction

7.2. Limits of layered structuring

7.3. The XL concept

7.4. Conclusion

7.5. Bibliography

Chapter 8. Relevance of the DTN Architecture to Mobile Ad Hoc Networks

8.1. Introduction

8.2. Mobile ad hoc networks

8.3. Challenged networks

8.4. Delay-tolerant networks

8.5. Relevance of DTNs to ad hoc mobile networks

8.6. Conclusion

8.7. Bibliography

Chapter 9. Intelligent Interfaces and Mobile Communications

9.1. Introduction

9.2. Assisting the user with access to new internet services

9.3. Modeling user behavior

9.4. Synthesis of mobile and wireless networks

9.5. References for intelligent interfaces for access to mobile networks

9.6. Conclusion

9.7. Bibliography

Chapter 10. Routing and Mobility Management in Personal Networks

10.1. Introduction

10.2. Personal environments

10.3. Routing in personal environments

10.4. Gateway discovery

10.5. Mobility management

10.6. Conclusion

10.7. Bibliography

List of Authors

Index

First published 2008 in France by Hermes Science/Lavoisier entitled: Les systèmes embarqués communicants : mobilité, sécurité, autonomie © LAVOISIER 2008

First published 2010 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

ISTE Ltd27-37 St George’s RoadLondon SW19 4EUUK

John Wiley & Sons, Inc.111 River StreetHoboken, NJ 07030USA

www.iste.co.uk

www.wiley.com

© ISTE Ltd 2010

The rights of Francine Krief to be identified as the author of this work have been asserted by her in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Cataloging-in-Publication Data

Systèmes embarqués communicants. English

Communicating embedded systems : network applications / edited by Francine Krief.

p. cm.

Includes bibliographical references and index.

ISBN 978-1-84821-144-5

1. Networks on a chip. I. Krief, Francine. II. Title.

TK5105.546.S9713 2010

621.3815’31--dc22

2009041894

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-84821-144-5

General Introduction1

Embedded systems surround us and assist us in our daily lives. They are ubiquitous and dedicated to a precise task, and can be distinguished at application level as well as performance level. They are usually intended for wireless communication and have a complex design, as we often have to juggle very strict constraints in terms of integration and functionality (surface, power consumption, throughput, etc.).

Today embedded systems are at the heart of the convergence of electronics/information technology (IT)/telecommunications and networks. This convergence requires us to familiarize ourselves with a range of disciplines. This book, compiled by experts in electronics, computer science, telecommunications and networks, aims to achieve this. Without being able to give a detailed discussion of all aspects relating to embedded systems design, this book comprehensively covers the issue of communication in embedded systems. This choice is easily justified by the fact that embedded systems are today overwhelmingly communications oriented and that communications and networks are an important sector for embedded systems.

This book consists of 10 chapters.

Chapter 1 is an introductory chapter, which presents the general characteristics of an embedded system, as well as the constraints that have to be considered at the design stage. This chapter provides an example of the production of an embedded system for video acquisition, processing, and display. This example is interesting because it allows us to emphasize an important element in future embedded system design: joint hardware/software development, referred to as codesign.

An important characteristic of an embedded system, as we have already said, is its ability to communicate with the outside world. Ad hoc networks offer interesting opportunities for enabling mobile devices to exchange data with each other, using their neighbors as relays if necessary, without needing an infrastructure to be set up beforehand.

Chapter 2 presents the characteristics of ad hoc networks, their limits, and the challenges that they present, notably concerning efficient routing strategies. In effect, enabling mobile devices to transmit data with time and bandwidth constraints is a difficult problem, given the diversity of QoS (quality of service) requirements and the characteristics of ad hoc networks, such as frequent changes in topology, energy constraints, and limited bandwidth. This chapter presents the main solutions to the problems encountered with embedded systems that are subject to stringent time constraints.

Sensor networks constitute a particular type of ad hoc network, which are distinguished by their size, which can be up to tens of thousands of nodes. The sensors, true embedded systems, are interconnected by wireless links and form the sensor network. An important issue emerges at this point of how to control the energy consumption of a system.

Chapter 3 is devoted to sensor networks and their management. Often installed in hostile environments, they must be as autonomous as possible for a large number of years. This means optimizing radioelectric communications, which have high energy consumptions, using appropriate routing algorithms. It is also necessary to allocate evolved management functionality to sensor networks, which allow them to manage themselves in order to improve their efficiency and operation without the need for human intervention.

Sensor networks, notably with the development of home automation, are set to invade our daily lives. This is already happening to some extent in the case of radiofrequency identification technology (RFID) technology. We could also cite the increasingly widespread application of user identification by contactless microchip cards in numerous public transport systems.

Chapter 4 covers RFID. The various types of RFID systems are presented according to the possibilities that they offer in terms of data processing and storage. The de facto standards that apply to every user of this technology are also described. Finally, numerous applications using this technology are presented, such as applications giving access to services, for which it is indispensable to protect the RFID system against any kind of attack.

The question of security in embedded systems, of their design, of the data that they memorize and exchange, is currently a major problem that needs to be considered from a hardware and software perspective. Highly constrained, the development of embedded systems presents an obstacle to the direct use of the currently available software and hardware security solutions that were developed for other purposes, such as desktop computers or servers. It is, therefore, necessary to develop solutions adapted to embedded systems, which are adequate for their specific needs and which respect the relevant constraints in development.

In Chapter 5 we explore some security issues in embedded systems and give some original and interesting hardware protection solutions. We present some secured hardware architectures that make use of these solutions to protect software and embedded data, intellectual property, or communications (again). Finally, we present an example of a secured embedded system running on an architecture that offers high performance — thanks to the hardware implementation — and flexibility — thanks to its reconfigurability.

Chapter 6 discusses communications security in embedded communications systems. First of all we present some communications security threats, and then we describe the security services that enable us to protect ourselves against such threats, as well as the two best known security protocols, i.e. IPsec and SSL/TLS. The implementation of security in an embedded system poses a certain number of problems that justify the necessity to adapt these mechanisms to this environment. We propose a number of existing adaptation solutions, and an example illustrating the feasibility of a secured connection in the embedded system concludes this chapter.

Future embedded systems will also have to be capable of adapting dynamically to changes in network conditions, while guaranteeing a QoS that is acceptable to the end-user. This adaptation can be effectively implemented by “cross-layer” approaches, which define methods of exchanging information between layers for a global optimization of the system.

Chapter 7 presents state-of-the-art “cross-layer” mechanisms for embedded communications systems. All the layers of the TCP/IP model, on which the majority of communications architectures in embedded systems is based, are covered, in order to identify the limits and inadequacies for protecting wireless networks and multimedia stream. After this, a definition of the concept of “cross-layer” is presented, detailing the different approaches, as well as its advantages for improving performance and communications. Finally, work done on each of these approaches is presented, as well as the optimization objectives of each technique, the layers that are made to collaborate and the parameters exchanged between the layers.

Embedded communication systems can also be mobile. This adds extra constraints regarding data transmission, as a path can suddenly disappear on occasions. Delay-tolerant network (DTN) architecture was devised in order to remedy the problems of intermittent connectivity in links, which can lead to long and variable time delays and high error rates.

Chapter 8 is intended to show the contribution that DTN architecture can make to mobile ad hoc networks. First of all, we present the specifications and basic concepts of DTNs, and then we detail the contribution of this architecture within a framework of mobile ad hoc networks, such as sensor networks. We also propose an adaptation of this architecture in order to limit the amount of supplementary processing. Regarding the DTN architecture that is currently being studied, we can expect rapid, innovative improvement in this area.

Mobile communications represent a domain that is currently in expansion. A few years ago the worldwide number of mobile telephone subscribers overtook the total number of subscribers to fixed telephone lines. The next generation of networks will be characterized by the integration of different wireless mobile network technologies. The mobile phone, an embedded communication system par excellence, would have to use an intelligent interface with the task of facilitating the mobile user’s access to the network while guaranteeing a QoS corresponding to his or her profile.

In Chapter 9 we present some ideas relating to intelligent user interfaces, their properties, and their applications within a mobile communications framework. We give an example of an intelligent user interface, capable of negotiating a QoS for a mobile user. WiMAX technology, which can support QoS and user mobility simultaneously, is described. Finally, we devote some space to projects involving user mobility prediction and intelligent interfacing for user profile management.

Chapter 10 concludes the book. It is dedicated to routing and mobility management in future personal networks. Firstly, we define the notion of personal networks: a network formed from the set of different embedded communications systems belonging to the same user. A routing protocol adapted to this environment is presented. It also enables us to consider the rules and policies necessary for cooperation and for establishing routes and communications between personal networks. We also describe a gateway-discovery protocol. Finally, we present a mobility management architecture for personal environments, as well as an extension to the IEEE 802.21 standard, which allows us to effectuate a multi-hop “handover”.

This book covers several aspects of embedded systems. In particular it describes some interesting state-of-the-art technologies that address the problems of communications in this domain.

Embedded communication systems are today at the heart of an important economic market, which is one of the driving forces in the new technology sector.

1 Introduction written by Francine KRIEF.

Chapter 1

Introduction to Embedded Systems1

1.1. Introduction

What do a mobile phone, a DVD player, a games console, an ADSL modem, a microwave oven, a car, and a rocket have in common? Our immediate response would be that:

they are all autonomous electronic devices;

they contain software designed specifically for a well defined task;

they communicate with the outside world;

they operate within an environment which is often outside their control.

All these characteristics are general characteristics of electronic devices that are known as embedded systems (ES). In recent years we have seen a sudden rise in interest in the design techniques involved in embedded systems.

Of course, the subject is hardly new or revolutionary, as we could say that these systems have been around for at least 40 years (for example, the guidance system in the Apollo lunar mission in the 1960s).

What is new is more the fact that today we can observe a convergence of different disciplines which often tend to be overlooked:

electronics,

IT,

telecommunications and networks.

Today, embedded systems are at the heart of this convergence and we will be able to convince ourselves of this throughout this book. Figure 1.1 illustrates this convergence.

Figure 1.1.The convergence of electronics, IT, and telecommunications and networks

This convergence also determines the interdisciplinary nature of design teams. This is what makes embedded systems an exciting field to work in: the task of making information technology (IT), networks and electronics research and development (R&D) teams collaborate on a single subject in a common setting.

This introductory chapter is intended to present the general characteristics of an embedded system and its design. It also aims to provide the important ideas and concepts to support the following chapters.

1.2. Embedded system: a definition

We can see that embedded systems are all around us and assist us in our daily lives. We unknowingly encounter dozens of them each day, while we generally use a single computer for work purposes.