Short-Range Wireless Network Integration in Intelligent ...831644/FULLTEXT01.pdf · MasterThesis...

Master ThesisElectrical EngineeringThesis no: MSE - 2007 - XXJune 2007

Short-Range Wireless NetworkIntegration in Intelligent

Environments

Mounchili Mama

School of EngineeringBlekinge Institute of TechnologySE - 371 79 KarlskronaSweden

This thesis is submitted to the School of Engineering at Blekinge Instituteof Technology in partial fulfillment of the requirements for the degree ofMaster of Science in Electrical Engineering. The thesis is equivalent to 20weeks of full time studies.

Contact Information

Author : Mounchili MamaE-mail : [email protected]

University advisor : Dr. Lennart IsakssonDepartment of Telecommunication SystemsEmail : [email protected]

School of EngineeringBlekinge Institute of TechnologySE - 371 79 KarlskronaSweden

Internet : www.bth.se/tek

To my Parents and Siblings

Abstract

The advent of low powered battery computing devices such as laptops, per-sonal digital assistants (PDAs), faced up new challenge when it come tosharing information and available resources. We need to adopt a more reli-able and efficient or cost effective approach to interconnect them togetherin order to make various services access possible. The idea of wired connec-tivity is to be discarded since do not fit with the cost policy and not selforganizing as generally requires human intervention. Therefore consideringthe reliability aspect, the breakthrough for such application, is to design ashort range wireless network that will enable automatic connectivity andimmediately share data among them.

In many circumstances, short-range wireless networks like Bluetooth servesas a prototype environment for demonstrating ad-hoc network access inintelligent environments. If we believe all of the hype surrounding Blue-tooth technology, we can expect our fridge to use our mobile phone to ordergroceries over the Internet, and, of course, end up ordering an extremelyexpensive new car instead of a steak. The ability to access such servicesheavily depend on the platform providing integrated and discovered services.Bluetooth devices must register as platform services that need to be avail-able as Bluetooth services. In both environments, system integration mustbe performed and additional communication link must be established. Thegoal of the work is to enable access services on an integrated non-Bluetoothintelligent system via Bluetooth enabled device (Client-Server architecture),vice versa.

Finally the design and implementation of a prototype application support-ing short-range wireless network is implemented in embedded Java APIs forBluetooth Wireless.

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Acknowledgements

I would like to express my sincere thanks to my supervisor Dr. LennartIsaksson for his constructive comments as well as useful advice throughoutthe thesis work.

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Contents

Contents iv

List of Figures vii

List of Symbols and Abbreviations ix

1 Introduction 11.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . 11.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.3 Related Works . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 Scope and Objective . . . . . . . . . . . . . . . . . . . . . . 41.5 Outline of the Thesis . . . . . . . . . . . . . . . . . . . . . . 51.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 Service-Oriented Architecture 72.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.2 Service-Oriented Architecture Features . . . . . . . . . . . . 72.3 Basic architecture . . . . . . . . . . . . . . . . . . . . . . . . 82.4 Basic Services . . . . . . . . . . . . . . . . . . . . . . . . . . 92.5 Elementary Service Oriented Architecture . . . . . . . . . . 102.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 Short Range Technologies 133.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.2 Bluetooth versus Infrared . . . . . . . . . . . . . . . . . . . 163.3 Bluetooth versus WLAN IEEE 802.11 . . . . . . . . . . . . . 173.4 Wi-Fi versus Bluetooth . . . . . . . . . . . . . . . . . . . . . 183.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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4 Bluetooth Technology 214.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 214.2 Wireless Data Transfer: PDA to Phone . . . . . . . . . . . . 214.3 Connection Sharing: Laptop to Phone . . . . . . . . . . . . 234.4 Personal Networks: PC to PC . . . . . . . . . . . . . . . . . 234.5 Cable Replacement: PC to Peripherals . . . . . . . . . . . . 244.6 The Power User . . . . . . . . . . . . . . . . . . . . . . . . . 244.7 Interoperability: Any Device to Any Device . . . . . . . . . 254.8 Bluetooth in the Small Office or Home Office . . . . . . . . . 254.9 Bluetooth for Voice Applications . . . . . . . . . . . . . . . 254.10 Bluetooth for Wireless Gaming . . . . . . . . . . . . . . . . 264.11 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5 Java APIs for Bluetooth Wireless 275.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 275.2 Basic Bluetooth Components . . . . . . . . . . . . . . . . . 275.3 Stack Initialization . . . . . . . . . . . . . . . . . . . . . . . 285.4 Device Management . . . . . . . . . . . . . . . . . . . . . . 295.5 Device Discovery . . . . . . . . . . . . . . . . . . . . . . . . 30

5.5.1 Discovery Agent . . . . . . . . . . . . . . . . . . . . . 305.5.2 Discovery Listener . . . . . . . . . . . . . . . . . . . 30

5.6 Service Discovery . . . . . . . . . . . . . . . . . . . . . . . . 315.6.1 The Service Discovery Database . . . . . . . . . . . . 315.6.2 Service Record . . . . . . . . . . . . . . . . . . . . . 31

5.7 Data Element . . . . . . . . . . . . . . . . . . . . . . . . . . 325.8 Service Registration . . . . . . . . . . . . . . . . . . . . . . . 325.9 Communication . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.9.1 L2CAP versus RFCOMM . . . . . . . . . . . . . . . 335.10 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6 Design and Implementation 356.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 356.2 Components Architecture . . . . . . . . . . . . . . . . . . . 366.3 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366.4 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . 376.5 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

7 Conclusion and Future Research 41

vi CONTENTS

7.1 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417.2 Devices of the Future . . . . . . . . . . . . . . . . . . . . . . 42

7.2.1 Bluetooth Locator System . . . . . . . . . . . . . . . 427.2.2 Personalized Family Car . . . . . . . . . . . . . . . . 437.2.3 The New Arcade: A Restaurant Lobby . . . . . . . . 43

7.3 Future Research . . . . . . . . . . . . . . . . . . . . . . . . . 43

Bibliography 45

Index 49

List of Figures

2.1 BlueClient and BlueJ2Server Connection architecture . . . . . . 82.2 A Basic Software Architecture . . . . . . . . . . . . . . . . . . . 82.3 Adding a Service Oriented Component . . . . . . . . . . . . . . 11

4.1 The short antennae on HP iPAQ 5400 series Pocket PC allowsit to communicate via. . . . . . . . . . . . . . . . . . . . . . . . 22

4.2 Bluetooth Technology Connection scenario. . . . . . . . . . . . . 234.3 Bluetooth scaternet. . . . . . . . . . . . . . . . . . . . . . . . . . 24

5.1 The stack initialization . . . . . . . . . . . . . . . . . . . . . . . 295.2 The Service Discovery Database (SDDB) . . . . . . . . . . . . . 325.3 The Generic Connection Framework and Bluetooth Connection

Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.1 Conceptual Model for Java Message Service. . . . . . . . . . . . 366.2 Typical Helper architecture . . . . . . . . . . . . . . . . . . . . . 376.3 BlueJ2seServer initialization screen-shoot . . . . . . . . . . . . 386.4 BlueClient and BlueJ2seServer pairing screen-shoot . . . . . . . 396.5 BlueJ2seServer Executing BlueClient’s commands screen-shoot . 406.6 BlueJ2seServer Executing "ShutDown" Command issued by Blue-

Client screen-shoot . . . . . . . . . . . . . . . . . . . . . . . . . 40

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List of Symbolsand Abbreviations

Abbreviation Description Definition

API Application Programming Interface page 36BCC Bluetooth Control Center page 34CCK Complementary code keying page 15CoD Class of Device page 29DSL Digital Subscriber Line page 15DSRC Dedicated Short Range Communication page 3DSSS Direct Sequence Spread Spectrum page 15ETC Electronic Toll Collection page 3FTP File Transfer Protocol page 21FHSS Frequency Hop Spread Spectrum page 14GPS Global Positioning System page 33HTTP Hypertext Transfer Protocol page 21HVAC Heating, Ventilating and Air-Conditioning page 2IMAP Internet Message Access Protocol page 21ISM Industrial scientific and medical page 2IrDA Infrared Data Association page 19ITS Intelligent Transport Systems page 3IVC Inter-Vehicle Communication page 3JABWT Java APIs for Bluetooth Wireless Technology page 41JCP Java Community Process page 41JMS Java Message Service page 35JVM Java Virtual Machine page 31MIDlet Mobile Information Device toolkit page 36OFDM Frequency Division Multiplexing page 15PDA Personal Digital Cellular page 25

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x LIST OF SYMBOLS AND ABBREVIATIONS

Abbreviation Description Definition

PDC Personal Digital Assistant page 3PHS Personal Handy phone System page 3SDP Service Discovery Protocol page 31SOA Service-Oriented Architecture page 11SDDB Service Discovery Database page 33SMTP Simple Mail Transfer Protocol page 21RVC Road to-Vehicle Communication page 3USB Universal Serial Bus page 24UUID Universally Unique Identifier page 32VICS Vehicle Information and Communication Sys-

tempage 3

WLAN Wireless Area Network page 23

Chapter 1

Introduction

1.1 Problem Statement

The emergence of new technologies pave the way to the proliferation of newdevices that sometimes need to be interconnected in order to access or shareavailable resources or services among them. This raises an issue or challengeof inter-device connectivity that is a very dominant mechanism that appearsto be complex, leading to much complication due to different protocols anddesign aspect. Therefore how communication between these devices doesactually take place? The answer to this question raises a problem of networkflexibility, which could eventually be solved by using a wireless solution.We are now to face up a new dilemma about proper type of technologiesthat are either expensive and therefore not compatible with price-consciousconsumer products, or a low-power and cost-effective ones, such as Blue-tooth in [1] capable creating wireless unconscious and ad-hoc connectivitybetween devices.

Hence wireless connectivity offers us immense freedom and convenience.It allows us to perform tedious tasks with a minimum of intervention, al-lows some of our devices to have dual functionality, and makes the vastamount of cables we we without sometimes leave in the office redundant.Bluetooth technology "will" change the suppositions we all have about ourelectronic devices. With the cables gone, the idea of having a particularappliance for a specific job will be irrelevant. With many of the devices al-ready available to consumers, this scenario grows closer to reality every day.

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2 CHAPTER 1. INTRODUCTION

The aim of the current chapter is to brush out general idea what shortrange connectivity with some applications that lay out foundation for thisthesis. It is structured as follows: Section 1.2 presents the author’s mo-tivation for this thesis; Section 1.3 presents related work that have beenconducted by previous researchers; Section 1.4 presents the scope and ob-jective of the Thesis; Finally Section 1.5 provides a brief outline of thechapters that are part of this thesis.

1.2 Motivation

The device connectivity raised in Section 1.1 is an important issue thatenable computing handy or transportable devices as well as laptops andpersonal digital assistants (PDAs), the possibilities to share or exchangeavailable resources such as data or services wirelessly from one device toanother vice versa, this without restriction nor constrain. Hence the needfor a short range wireless networks that could make it possible for a widevariety of new wireless appliances to be connected within a vicinity for re-sources sharing.

Other considerable application area for short range wireless networks canbe found in: Industrial scientific and medical (ISM), consumer electronicsand smart home appliances. The models for these networks include:

• control of machines and devices in the process and automation indus-try, but also in smart home appliances wirelessly

• temperature, pressure or gas sensors, valves and actuators, e.g. forheating, ventilating and air-conditioning (HVAC)

• medical monitoring (intra- and extra-corporal)

• environmental monitoring, e.g. distributed in towns.

Nevertheless, the cost issues raised in [2] may create another setbackthat is likely to put foremost limitations for the design process of such wire-less applications, since the lower the cost per node, the higher is the amountof applications and devices.Therefore, for this short-range wireless connectivity, some additional chal-lenges must be taken into consideration such as: (i) topology issues, i.e.self-organizing, ad hoc and mesh networking; (ii) device issues, i.e. efficient,

1.3. RELATED WORKS 3

modular, low-cost and power-saving implementation; and (iii) security is-sues.

1.3 Related Works

In the past some work has been conducted by researchers in the field ofshort range wireless networks. This section present some realization madeso far that will enlighten the backbone for this study and pave the way tothe design and implementation of such network.

K. Tokuda in [3] developed wireless communication technology for In-telligent Transport Systems(ITS). According to his findings the DedicatedShort Range Communication (DSRC) system based on the wireless com-munication technologies is vital for supplying ITS services by means of theinformation and communication network known as Smart Gateway that iscomposite of the wireless communications systems, such as Road to-VehicleCommunication (RVC) system and Inter-Vehicle Communication (IVC) sys-tem. Moreover, Vehicle Information and Communication System (VICS)along with Electronic Toll Collection (ETC) system are considered to bethe ITS particular wireless link. The DSRC-RVC system as well as bothPersonal Digital Cellular (PDC) and Personal Handy phone System (PHS)is similar to a mobile communication system. Besides that, the DSRC-IVCsystem creates an ad-hoc network in which the vehicle control data is passedon between a car and another one in the vicinity [4]. The service contentssuch as the platooning operation, the bumping avoidance, the control ofmerging/diverging vehicle are included in the DSRC-IVC system.

Petar P. And Tatiana K. Presented in [5] conducted a simulation mea-suring the performance results represented by the average period of thediscovery protocol, calculated in time slots, as a function of the total num-ber of devices in the network deploys the network without any predefinedinfrastructure. The result is presented as a diagram showing Average dura-tion of the discovery protocol as a function of the number of devices.

David G. Leper in [6] worked extensively on Ultra-wideband as a nextstep in short range wireless and came out with four trends that has beenpushing forward the grow of short range wireless:

1. increasing demand for wireless data capability in portable devices at


higher bandwidth and at lower cost and power consumption than thatenvisioned for third generation cellular,

2. crowding in radio spectra that regulator authority,

3. segment and license in traditional ways,

4. growth of high-speed wired access to the Internet in enterprises, homes,and public spaces,

5. shrinking semiconductor cost and power consumption for signal pro-cessing.

According to his findings someone can take benefit of the dividends ofshort-range wireless explicitly, low power, low cost, and high speed, usingunlicensed spectrum that is re-usable numerous times over and over.

Yufeng Zhao and Michael S. Hsiao in [7] propose a method how powerconsumption can be reduced by using the retransmission in short rangewireless network. According to them, reducing the signal power level, andincrementing the retransmission rate therefore affect the entire energy con-sumption are evaluated theoretically. They proposed a new way of dynami-cally altering the signal power to make the power utilization as a minimumas possible. During the same investigation it is established that reducing thesignal power seemingly will increase the probability of incorrect transmissionof the frame. Nevertheless, with adaptive retransmission at changing powerlevel, will certainly rise up the power efficiency again whereas maintainingalmost the identical frame loss rate and transmission delay.

1.4 Scope and Objective

Having gone through the work initiated for instance by K. Tokuda in [3] inthe case of Intelligent Transport Systems and Petar P. And Tatiana K. Pre-sented in [5] of device discovery, it seem to be suitable kick off going beyondthe scope of those applications and widen with variety wireless services ac-cessible from handy device for instance. This in order to cope with futurelocal services on demand wireless in nature via short-range wireless net-works. Such networks application in areas such as garage-door openers, TVremote and remote keyless entry (etc) or within the free industrial scientificmedical (ISM) frequency band. For proper operation of such wireless net-work, it must be driven by a certain technology. Several technologies such

1.5. OUTLINE OF THE THESIS 5

as Bluetooth, Infrared Data Association (IrDA), Wi-Fi, Ultra-Wideband,WiMAX, and ZigBee have to be investigated. Hence considering the aspectsand its constraints of today’s and its impact on near future technologies.This will be conducted through several information sources such as articlesand standards.

As an illustration a use case [8] scenario with Bluetooth will be usedafter confronting with others as technologies.

Owing that services are varying in nature depending on the environ-ment, the main task here is to implement a short range wireless networkthat adapts or integrates itself within an environment in order to accessservices. The implementation is done theoretically and through simulation.At the onset of the thesis the first task was to investigate all the technologiesthat are involved in short range wireless design, and then confront togetherto sort out the one that fits the design.

The thesis encompasses the goal to generate simulation environmentthat could be used as platform for future studies within the area of shortrange wireless networks in a varying environments.

It would have been perfect idea to extend service to the next level suchas designing a browser a connected devices, such as handy phone connectedto laptop to surf internet. Unfortunately due to time limitation it couldn’tbe possible. Nevertheless it deserves serious attention in order to make it apriority for future work.

1.5 Outline of the Thesis

The outline and structure are as follow: in Chapter 2, Service-OrientedArchitecture is presented where new added services have less constrain ontechnology (focussing more on business and less on technology) with reusecapabilities as spacial feature; while in Chapter 3 various technologies in-volved in short range wireless network implementation are discussed, henceweighting both advantage and disadvantage with respect to their applica-tion area. Bluetooth technology is introduced in Chapter 4 since standstall among the wireless standards with respect to worldwide device deploy-ment. Owing that any given technology will have to be fed with command(clients request) for execution, there is a need for a driver (software) that


will convert various commands into execution such as the Java ApplicationProgramming Interface (API), that will be presented in Chapter 5 as driverfor Bluetooth Wireless Technology in the thesis. The design and implemen-tation that includes demo is described in Chapter 6. Finally the conclusionis presented in Chapter 7 with a provision for future research.

1.6 Summary

The new trends and necessity of short range wireless connectivity have beenemphasized in the problem statement, while the usefulness of deploying suchwork discussed in the motivation. As illustration, some earlier works in thefield have been presented the related work section. The future target forsuch application have been presented in the scope and objective. Finally thestructure of the overall thesis work presented in section thesis outline. Thereason to execute this study is to extend the work done by by K. Tokuda[3] and Petar P. And Tatiana K. [5] as ideal start up for the thesis.

Chapter 2

Service-Oriented Architecture

Owing the services are varying in nature, this chapter presents a new ap-proach known as Service-Oriented architecture (SOA) as a novel approach tobuilding Information Technology systems that allows businesses to leverageexisting resources and effortlessly allow the unavoidable changes requiredto support the business.

2.1 Introduction

SOA can be considered as an architecture for building business applica-tions as a set of loosely coupled as in [9] (refereing to how two compo-nents interact within a SOA) black-box (SOA deliberately hides complexitywherever possible) components orchestrated to deliver a well-defined levelof service by linking together business processes.It is worth mentioning herethat in the thesis that businesses represent a group of Services located inthe Blue2Jserver database, that need to be accessed by the BlueClient asdepicted in Figure 2.1.

2.2 Service-Oriented Architecture Features

Owing to the changing nature of Services, requests for new programs keepcoming. Hence the need to organize programs for easy reuse as in [10], foreasy maintenance and support, for coherent, and for easily sharing data andresources. And that, framework is the idea behind service oriented archi-

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8 CHAPTER 2. SERVICE-ORIENTED ARCHITECTURE

tecture.

The software architecture defines which software components to useand how those components interact with each other (BlueClient and theBlue2Jserver) according to Figure 2.1. Creating a service oriented architec-ture takes thought, patience, planning, and time. But one can start seeingreturns on a SOA investment very quickly, without having to rewrite allyour software.

Figure 2.1: BlueClient and BlueJ2Server Connection architecture

2.3 Basic architecture

Figure 2.2 shows the underlying software architecture for an order-processingapplication [11], that allows BlueClient to place orders to the BlueJ2server.It has the following five components:

Figure 2.2: A Basic Software Architecture

2.4. BASIC SERVICES 9

The Browser is a program located on a user’s device (PC, laptop, PDA, orcellphone) that accesses the services. Many users can access the applicationat the same time, so many browsers will typically link to the services lits.The primary job of the browser is to display information and accept inputfrom the user.

Services List manages when and how the many request are sent to thebrowsers of the users who access the services.

The Order-Processing Application carries out the services process thatis being executed, which in this case means carrying out the necessary stepsto accept the order and fulfill the Client’s request, if possible.

The Database Server is computer software that reads data from a databaseand sends the data where it is needed.

The Database is where the definitions of the services data and the dataitself are stored.

Information passes from the browser to the services List to the order-processing application, which decides what to do next. For instant when Irun several programs from my mobile device lets say Matlab, Mathematical,LATEX(etc) the order of the Laptop (server) responds according to the FIFOor pipeline method.

The order-processing application might pass data to the database serverto write to disk, or it may request data from the database, or it may sim-ply send information back to the browser through the Services list. Whatthe order-processing application does depends upon the information andcommands passed to it by the user via the browser.

2.4 Basic Services

A service is something we expect to pay for, after use [12]. For instancewe may pay for electrical service, telephone service, and service at a restau-rant. For simulation purpose my services are several program installed onmy Laptop that could be ran from my mobile phone.

10 CHAPTER 2. SERVICE-ORIENTED ARCHITECTURE

Therefore taking a particular case of restaurant for instance, we sit downat a table, consult a menu on the mobile phone, give our order by sendinga request to the waiter (server), and the meal is delivered as soon as itis prepared. We pass a simple set of information to the waiter (what wewant to eat and drink), and somehow, magically, the restaurant provides it.Usually, we don’t see the food cooked or participate in its preparation orserving. The meal is the service that we pay for in the case of restaurant.

One can talk about the restaurant in terms of components and how theyinteract. We order food from the waiter which acts as a service. The waitersends or takes the order to the kitchen. The kitchen prepares the food andalerts the waiter, who then, we hope, brings us what we asked for. Thecustomer, waiter, and the chef do have different roles. The SOA of therestaurant encompasses these various roles.

2.5 Elementary Service Oriented Architecture

In a SOA [13], services interact with each other in ways similar to howthe various services of the restaurant interact. We can now think of therestaurant from two levels from the business services level, which describesthe functions and how they interact, and from an "implementation" point ofview, that is, how the food actually gets prepared, how it actually gets ontothe plate, and so on. The various services pass information, ask for tasksto be performed, and serve up the results. We can illustrate this divisionof function by adding a new credit-checking component to our previousarchitecture diagram in [14].

In Figure 2.3, we add an extra service known credit-checking component.Its service is called on when new customers place an order to determinewhether they are creditworthy. In the figure, we don’t show or even careabout how the credit checking is done. For the sake of simplicity, say thatthe credit-checking software component is run by an external company andsimply provides a service. The company using this credit-checking softwareis confident that the service conducts a credit check in the right way.

The order-processing application simply requests the credit-checking ser-vice and passes along the necessary information (a person’s name and SocialSecurity number). The credit-checking component consults its informationsources, does some calculations, and passes back a credit rating. The creditchecking component may connect to many computers, consult many differ-

2.6. SUMMARY 11

Figure 2.3: Adding a Service Oriented Component

ent data sources, and use a very sophisticated algorithm to calculate thecredit rating, but this is of no concern to the order-processing application.As far as the order-processing application is concerned, credit checking isjust a black box.

Also, we need to emphasize that the credit-checking component doesonly credit checking. It doesn’t offer a wide range of services. It is preciselybecause the components have a narrowly defined scope that is, they do "justone thing" that they can be used and reused as building blocks.

SOA’s use and reuse of components makes it easier to build new appli-cations as well as change existing applications. Using well-proven, testedcomponents makes testing new applications more efficient.

2.6 Summary

The promise of service oriented architecture is to liberate business from theconstraints of technology and unshackle technologists from the chains theythemselves have forged.As illustration in this chapter, an extra service known as credit checkingsystem has been added to the existing order processing system withoutaffecting its normal operation.

Chapter 3

Short Range Technologies

This chapter presents various technologies involved in the implementationof a short range wireless networks. It also present their characteristicsdepending on their application area in order to sort out what suit bestfor such design, finally make comparison between them.

3.1 Introduction

There are several standards available for connecting a variety of devices. Onthe other hand each device is compelled to support more than one standardin order to make it inter-operable among different devices such as the sce-nario of setting a network in offices. In such situation, whole office buildingsmust make provisions for lengths of cable that spans long distance throughconduits in the walls, floors and ceilings, to workers’ desks. Such scenariosuffers from serious setback especially when any faulty operation occurs.For this reason there is a need for a cable replacement. The obvious alter-native here can only be wireless solution.

As mentioned in Section 1.4 the possible technologies that could supportshort range wireless connectivity are discussed as follow:

Bluetooth: Bluetooth is a high-speed, low-power microwave wireless linktechnology, intended to connect phones, laptops, PDA as well other handyequipment that could be carried without much effort. Contrary to infra-red, Bluetooth does not necessitate line-of-sight positioning of connected

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14 CHAPTER 3. SHORT RANGE TECHNOLOGIES

devices. As discussed in [15], the technology is shaped from existing WLANtechniques however interesting with respect to its lightweight and affordablecost. each time any Bluetooth-enabled devices come within range of eachother, they instantly exchange address information and ready to create smallnetworks among each other, without user involvement or initiative. Thebluetooth has the following characteristics:

• restriction

• Operates in the 2.4 GHZ ISM band which is globally available with

• Uses Frequency Hop Spread Spectrum (FHSS)

• Able to support up to 7 other devices in a piconet

• Bi-directional, non line of sight transmission (through walls)

• 10 m to 100 m range depending on power

• Low cost

• Low power device, max 1 mW

Infrared Data Association (IrDA): IrDA is a worldwide organizationthat creates and advertises inter-operable, low-cost infrared data intercon-nection standards. The IrDA itself is a set of protocols including all layersof data transfer, moreover with some network management capabilities andinteroperability designs features according to [16]. The IrDA data takes theresponsibilities of data delivery and the IrDA Control on the other hand isresponsible for sending the control information. Commonly, IrDA providewireless connectivity technologies as cable replacement. IrDA as presentedin [17] is a point-to-point, narrow angle (300 cone), ad-hoc data transmis-sion intended to function within a distance of 0 to 1 meter with a speeds of9600 b/s to 16 Mb/s. The IrDA has the following characteristics:

• Operate within a range of at least 1 meter that can further be extendedto 2 meters. It consumes less power.

• It is a two way communication (bi-directional). Data transfer rangesfrom 9600 b/s with primary speed/cost steps of 115 kb/s and maxi-mum speed up to 4 Mb/s

• Data packets are protected using a Cycle Redundancy Check (CRC).

3.1. INTRODUCTION 15

WLAN IEEE 802.11: The goal of WLAN is to connect two relativelylarge devices that have lots of power at high speeds. Typically, this tech-nology is used to connect two laptops within 300 feet at 11 Mb/s. Thistechnology is also useful for network administrators who want to extendtheir LAN to places where it is either expensive or inconvenient to runcables. The WLAN has the following characteristics:

• Uses the Direct-sequence spread spectrum (DSSS) modulation tech-nique with Complementary code keying (CCK).

• Used in a point-to-multipoint configuration,

• Typical indoor range is 30 m (100 ft) at 11 MB/s and 90 m (300 ft)at 1 Mb/s.

Wi-Fi: Next to Bluetooth, Wi-Fi is by far the most booming and broadlydeployed short-range wireless technology. It is the trendy name given toproducts implementing the IEEE 802.11a/b/g local-area network (LAN)standard. It’s generally used in laptops linking home LANs as well as var-ious hotspots around the world. It can be noticable that most of laptopsnowadays come with Wi-Fi built in. However it doesn’t stop there sinceWi-Fi is landing in many other wireless applications where speed and rangeare critical. All is not just perfect since improvement are being made forthe next version of Wi-Fi, designated by the IEEE as 802.11n in the nearfuture with greater reliability.

Ultra-Wideband: It mostly addresses the wireless USB applications forPersonal Computer as well as laptop connectivity towards peripherals, dig-ital cameras, and other high-data-rate extensions. It is highly favored bycompanies willing to integrate wireless video connectivity for instance inconsumer electronics. However there is a wonder here whether it couldachieve the required performances.

WiMAX: It is the name of IEEE’s 802.16 high-speed wireless option fo-cussing on broadband solutions or wireless services. WiMAX uses orthogo-nal frequency-division multiplexing (OFDM) achieving up to 70 Mb/s for upto 30 miles. The objective of WiMAX is to deliver a wireless broadband ser-vices to remote access places without high-speed cable or digital subscriberline (DSL) Internet service. Some expert predict that WiMAX could de-liver higher speed over longer distance than Wi-Fi does in Laptops. It is


a device for future since the expected release date is toward the end of 2008.

ZigBee: It is meant for a short-range wireless technology compatible withlow-speed monitor and control applications. ZigBee is based on the IEEE802.15.4 PAN standard, delivering short-range (less than 10 m) connectiv-ity for remote measuring and simple control. For instance it is reliable forwireless sensor networks also monitoring and control operations such as inthe home, business, and industry. the only problem is that it is dearly tojoin the ZigBee Alliance in order to get accreditation for product.

Owing that the objective here is to sort out the best possible technologyamong others, easily accessible with cost effective approach, in the sub-sequent section some competing technologies fulfilling that criteria such asIrDA, WLAN 802.11b and Wi-Fi will be compared against Bluetooth tippedas most successful alternative and describe how it narrows the gap left byothers candidates.

3.2 Bluetooth versus Infrared

Wireless communication between two computers is not new. PDAs havebeen able to do that for years using infrared technology. Going into detailsof the benefits of provided by each technology, one can realise that Blue-tooth and IrDA are together significant to the marketplace.

Each technology has pro and con and neither can meet all users’ needs.Bluetooth’s ability to penetrate solid objects and its capability for maxi-mum mobility within the piconet allows data swapping applications thatare tricky or unfeasible with IrDA. For instance, with Bluetooth, a personcould synchronize their phone with a PC without taking the phone out oftheir pocket or purse (this is not possible with IrDA. The multi-directionalcapability of Bluetooth allows synchronization to start when the phone isbrought within range of the PC.

Meanwhile, in the case of applications with respect to one to one dataexchange, IrDA is preferable. For instance an application where there aremany people sitting across a table in a meeting. Electronic cards can beexchanged between any two participants by pointing the IrDA devices to-wards each other (because of its the directional nature).

3.3. BLUETOOTH VERSUS WLAN IEEE 802.11 17

On the other hand since Bluetooth is multi-directional in nature, theBluetooth device will detect all similar devices in the room and the userwould have to select the intended person from a list displayed by the Blue-tooth device (menu).

One drawback to infrared is that the devices involved must be a fewdistance apart, and most significantly, the infrared transceivers must bedirected to each other such as "eye to eye" direction. If either of thoseconditions isn’t satisfied, it will result to transmission failure. Bluetoothovercomes the first constraint by having a nominal range of about 10 me-ters (30 feet). Bluetooth overcomes the second constraint since it works likea radio; therefore transmissions are Omni-directional. Consequently, thereare no "eye to eye" or line-of-sight issues when communication takes placebetween two Bluetooth devices.

On the security front Bluetooth provides robust security mechanismswhich are absent in IrDA. Nevertheless the narrow beam (in the case ofIrDA) provides a low level of security. IrDA challenges Bluetooth when itcomes to cost related issue. A company can get an IrDA solution availablefor $1 US. Though Bluetooth seems expensive, there is a prospect of priceto fall in the near future.

3.3 Bluetooth versus WLAN IEEE 802.11

Bluetooth and WLAN were both created to accomplish two different ob-jectives, although both technologies operate in the same frequency band:2.4 GHz. However as previously stated the purpose of WLAN is to con-nect two comparatively huge devices having considerable power at largerspeed [6].

On the other hand, Bluetooth is intended to connect smaller devicessuch as PDAs and mobile phones within a range of 30 feet at a rate of 1Mb/s. Due to its slower data rates and shorter ranges abilities, the Blue-tooth could be ranged among low power wireless technology category. Con-trary to WLAN devices, some Bluetooth is able to consume 500 times lesspower, which makes huge impact on battery lifetime of many mobile devices.


Bluetooth is also intended to be used as a cable replacement technology.In the scenario where multiple peripherals are connected to a computer us-ing RS-232 or USB, Bluetooth could be the ideal solution in case one needsto use those devices wirelessly. It’s almost impossible to connect peripher-als to a computer using 802.11b technology (may be, except for printers).Bluetooth even has a built-in facility for wireless audio communication.

Still there is a question on whether a technology can replace another?Hardly, since Bluetooth will never replace 802.11b owing to its bad at han-dling as described below:

• Large file transfers between devices

• Long-range communication, only class 1 Bluetooth devices have arange of 90 m (300 feet)

On the other hand, 802.11b will never substitute Bluetooth for the followingreasons:

• 802.11b needs much power for communication.

• 802.11b wasn’t designed for voice communication.

In the wireless communication field, there is no technology that is suit-able for each possible application. Either Bluetooth or 802.11b could beused for wireless communication among computers. Both have their placein the market and can perform in their niches well. Newer WLAN proto-cols like 802.11a and 802.11g will obviously clear the distinction betweenBluetooth and WLAN since they extend 802.11b’s bandwidth restriction to54 Mb/s.

3.4 Wi-Fi versus Bluetooth

Wi-Fi and Bluetooth are intended to coexist in the network, and althoughthey certainly have overlapping applications, each has its distinct zones ofadvantage. The main differences betweenWi-Fi and Bluetooth are as follow:

Distance: Bluetooth is lower powered device, which means its signal canonly go short distances (up to 30 feet). 802.11 technologies can cover ownhome, and even more sometimes, depending on the antenna.

3.5. SUMMARY 19

Application: Bluetooth is considered as cables replacement. For instancein the situation where one has to get rid of huge tangle of cables linking forinstance mouse, printer, monitor, scanner, as well as other devices on deskand around home. It is important to notice here that the first Bluetooth de-vice was a Bluetooth headset, eliminating annoying cable to the telephone.Nowadays cars are also becoming fitted with Bluetooth so driver can usecell phone in car, with car’s stereo speakers and an onboard microphoneserving as hands-free capability.

Wi-Fi (IEEE 802.11a, 802.11b, and 802.11g) and Bluetooth are similar incertain conditions: for instance they both can make possible wireless com-munication between electronic devices but are more complementary thandirect competitors. Wi-Fi technology is mostly used to make a wireless net-work of personal computers that could be situated anyplace in a home orbusiness. Bluetooth devices usually on the other hand communicate withother Bluetooth devices in relatively close range.

3.5 Summary

In the wireless communication field, there is no technology that is best suitedfor every possible application. Either Bluetooth, IrDA, 802.11b or evenWi-Fi can be used for wireless communication between computers. Manytechnologies available in the market are vital in the sense that they canperform in their niches well. However Bluetooth, though quite novice in thearena, has emerged as the frontrunner in the confrontation known as "battlebetween competing technologies" with much importance or attraction it isluring from industries.

Chapter 4

Bluetooth Technology

Owing to the popularity of Bluetooth within wireless field, one can expectnumerous applications available for the technology. In this chapter someapplications for Bluetooth will be revisited, though we still expect manyothers in the near future that are still under development.

4.1 Introduction

Bluetooth is a wireless communication protocol that could be used to com-municate to two or more other Bluetooth-capable devices. In this sense,Bluetooth is like any other communication protocol that you may use ev-ery day like Hypertext Transfer Protocol (HTTP), File Transfer Protocol(FTP), Simple Mail Transfer Protocol (SMTP), or Internet Message AccessProtocol (IMAP). Bluetooth is also like these protocols in that it has client-server architecture. In Bluetooth, the one who initiates the connection (theclient) is the master, and the one who receives the connection (the server)is the slave. The purpose of this chapter is to highlight the problems thatBluetooth solves and give some scenarios for using this technology.

4.2 Wireless Data Transfer: PDA to Phone

Almost everyone owns a mobile phone nowadays. These devices are veryconvenient, compact, and cute (well, at least some of them). However, theysuffer from two major limitations:

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22 CHAPTER 4. BLUETOOTH TECHNOLOGY

Figure 4.1: The short antennae on HP iPAQ 5400 series Pocket PC allowsit to communicate via.

• Mobile phones have limited memory for phone book entries.

• Data entry on mobile phones can be cumbersome.

Entering data on a mobile phone is very tedious because we’re dealingwith a nine-button keypad to type alphanumeric text. Also, mobile phonesdon’t have a lot of memory for storage, so we’re limited to only 50 or 100entries. On top of that, we’ll also need to truncate some names when addingphone entries.

On the other hand PDAs are also useful devices. They can store thou-sands of contact entries, and they are a lot better for entering data comparedto mobile phones. Since useful for storing our entire contact list rather thanon the mobile phone. Unfortunately, it’s a little inconvenient to look upa phone number on the PDA and then manually dial the number on themobile phone.

With a Bluetooth-enabled PDA and a Bluetooth-enabled mobile phone,one can keep the entire contact list on the PDA where it’s far more con-venient. In this case it won’t be necessary to store phone numbers on thephone. Each time we are ready to place a call, we just look up the num-ber on the PDA and send the phone number over to the phone; no wires,no hassle. As shown on Figure 4.1 is a picture of one of HP’s advancedBluetooth enabled PDAs.

4.3. CONNECTION SHARING: LAPTOP TO PHONE 23

Figure 4.2: Bluetooth Technology Connection scenario.

Bluetooth and 802.11b. For added security, this model also includes afingerprint reader.

4.3 Connection Sharing: Laptop to Phone

For a regular user such as a programmer willing to connect his laptop to hisphone as shown in Figure 4.2, won’t be that easy to get a dial-up Internetconnection on the mobile phone. We may have an Internet-ready phone, butthe wrong cable instead or we may have the right cable (which is expensive),this will require additional software to establish the dial-up connection. Itmay happen that we sometimes need to connect two cables together toaccomplish this feat. Bluetooth eliminates all the hassle from this scenarioby creating a standardized method for wireless dialup networking. We caneven keep your wireless phone at our hip or in our purse while surfing theWeb on laptop. The same applies for PCs or PDAs that want to use thephone to connect to the Internet. This is really convenient whenever thebroadband connections at home go down for servicing, we place the wirelessphone in the vicinity of the PC to get connected.

4.4 Personal Networks: PC to PC

Bluetooth is great for connecting two PCs together at a moderate speed [18].If higher speeds is required or to transfer large files, then probably betteroff using WLAN technology. On the other hand, Bluetooth is good atcreating small, personal networks. So this is a great technology if we’rehaving an impromptu meeting with co-workers. Bluetooth also has theadded capability to discover new devices when they enter the network.


Figure 4.3: Bluetooth scaternet.

4.5 Cable Replacement: PC to Peripherals

The Bluetooth can operate like any other protocol to connect to peripheralslike in Figure 4.3, such as serial (RS-232), parallel, Universal Serial Bus(USB), or Fire wire. In the near future, the personal computer will beequipped with a Bluetooth "port" in the same manner that it currentlyfeatures a serial and USB port. Then one can use Bluetooth to connectto peripherals wirelessly and effortlessly. If it was required to make someprintouts with a Laptop in a remote location with no printer driver northe right cable, then we’ll need to give your file to someone who does haveit. If that person doesn’t have the right program to read the file, then noprinting will be possible. In case of a Bluetooth enabled laptop and thatprinter also does, (regardless of the manufacturer), then there won’t be anyproblem taking some printouts. Bluetooth can ask the printer for the rightdriver if not installed in Laptop, and proceed with files printing.

4.6 The Power User

With a multitude of peripherals that are to be connected, such as PDA, awireless phone, a printer or two, a scanner, an MP3 player, a digital camera,and a DV camera (etc). One can imagine the amount of power it mayconsume. Bluetooth solves all this by having virtually an unlimited numberof peripherals wirelessly connected to the computer. The only limitation isthat one can only have seven active connections at the same time. Thatshould be fine because it would be quite rare to print, scan, upload pictures,and synchronize PDA all at the same time.

4.7. INTEROPERABILITY: ANY DEVICE TO ANY DEVICE 25

4.7 Interoperability: Any Device to Any De-vice

In the previous scenario, non-Bluetooth-enabled devices are definitely notinteroperable. In other words, if we want to send a picture from the camerato the PDA, then we’ll need to use the computer to interconnect them. Thesame also goes if we want to scan a document and send it to the printer(i.e., to act like a copier) or send it to the PDA; it’ll always require PC toact like the "man in the middle." Of course, one can buy a cable or two todo some of those tasks, but those cables are rare and expensive. Bluetoothsolves all this by allowing devices to communicate among themselves withno hassle and with no cables. It’s essentially the universal cable.

4.8 Bluetooth in the Small Office or Home Of-fice

Setting shared peripherals among users such as printer required to buy aprint server. But that option seems to be a bit expensive. With Bluetooth,if users are in the range, no print server will be required because users canconnect to the printer as if it were a local printer. For that matter, theprinter should be able to print for every Bluetooth user within range. It isimportant to remember here that it can only handle seven active connectionsat the same time.

4.9 Bluetooth for Voice Applications

Bluetooth is efficient at transferring data wirelessly, but it also has the ca-pability to transmit voice and sound as well. So given a Bluetooth headset,one could use the same headset to answer calls on Bluetooth-enabled wire-less phone as well as answer calls on Bluetooth-enabled home phone. It ispossible to also use the same headset to listen to Bluetooth-enabled portableradio.

Bluetooth can also be enabled in car so that driver receives a call onwireless phone (though dangerous while driving), one can simply transferthe call to the hands-free system built right into the car while the phonestays on the hip, or in the briefcase. One can also use the same technology to


initiate a call in car without touching the phone at all. In either case, whileat destination and the conversation can be carried on by just transferringthe call back to the phone.

4.10 Bluetooth for Wireless Gaming

One could use Bluetooth for wireless gaming since it’s always a hassle whenone want to connect two handheld video game systems and play against afriend. Most connection cables could be about 6 feet long, so if both playerswere on a school bus, they needed to sit right next to each other to play.With Bluetooth, one just have to come within range of your opponent toplay.

4.11 Summary

The Bluetooth technology has a wide range of application as decried above.Now that the ins and outs of Bluetooth have been unearthed, it is probablyright time to find out how to integrate Bluetooth with Java.

Chapter 5

Java APIs for Bluetooth Wireless

In this chapter will be introduced formal introduction to the Java BluetoothAPI that will cover broad mainstream of the classes in the javax.bluetoothpackage as well as study how to use them in an applications.

5.1 Introduction

Instead of looking at every class and interface individually, a special ap-proach by first looking at the basic components of a typical Bluetooth ap-plication (Java or otherwise). Then component identification follows withexplanation how to use the Java Bluetooth API in order to create wirelessapplications [19].

5.2 Basic Bluetooth Components

The basic components of most of Bluetooth application are as follows:

• Sack initialization

• Device management

• Device discovery

• Service discovery

• Service registration

• Communication

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28 CHAPTER 5. JAVA APIS FOR BLUETOOTH WIRELESS

Besides that the Java Bluetooth Specification [20] adds special com-ponent called Bluetooth Control Center (BCC).It is required to exist in aJSR-82 [21] compliant implementation; however there is no guiding principlein the official Java Bluetooth specification about how it should be imple-mented. One vendor could implement the BCC as a set of Java classes, andanother vendor could implement it as a native application on the Bluetoothhost. But no matter how it is implemented, it is an integral part of securityarchitecture since the BCC defines device-wide security settings for yourBluetooth device.

5.3 Stack Initialization

Prior to doing anything, stack needs to be initialized as pictures in Figure5.1 [22]. A Bluetooth stack has direct way in to the underlying Bluetoothdevice. Stack initialization can consist of a number of things, but its mainpurpose is to get the Bluetooth device ready to start wireless communi-cation. Stack initialization sequences can vary, and it’s heavily dependentupon the underlying operating system and Bluetooth radio. In some casesno code is needed at all to initialize your stack. In other cases, one needto write a bit of code to get stack initialized because of the baud ratesspecification needed for RS-232 interface.

The following snippet code shows the stack initialization.

public void btInit() throws BluetoothStateException {localDevice = null;discoveryAgent = null;// Retrieve the local device to get to the Bluetooth ManagerlocalDevice = LocalDevice.getLocalDevice();// Servers set the discoverable mode to GIAClocalDevice.setDiscoverable(DiscoveryAgent.GIAC);// Clients retrieve the discovery agentdiscoveryAgent = localDevice.getDiscoveryAgent();}

As above mentioned, stack initialization must take place prior to anyreal work can be done in Bluetooth application either invoked directly orusing code

5.4. DEVICE MANAGEMENT 29

Figure 5.1: The stack initialization

5.4 Device Management

LocalDevice, RemoteDevice and DviceClass are the classes in the Java Blue-tooth specification that form the Generic Access Profile that enable us toperform device management. These classes enable us to query some statis-tical information about personal Bluetooth device (LocalDevice) and alsosome information on the devices within the area (RemoteDevice). TheDeviceClass object provides information about the official class of device(CoD) as defined in the Bluetooth specification.

The LocalDevice class is the class that provides information about thelocal Bluetooth device. Being a singleton object, one can only have a sin-gle instance of this object in Java Vertual Machine (JVM) at a time. Itsconstructor is private, so one can instantiate it by using the static getLo-calDevice() shown in the following snippet code:

LocalDevice localdevice = LocalDevice.getLocalDevice();


5.5 Device Discovery

At the onset the Bluetooth device has no idea of what other Bluetooth de-vices are in the area. May be there are laptops, desktops, printers, mobilephones, or PDAs within the vicinity. The possibilities are endless. In orderto find out, the Bluetooth device will use the device discovery classes thatare provided in the Java Bluetooth API to notice if there is anything withinthe neighborhood. At this stage arise another question about which Blue-tooth devices should use device discovery? In the situation we are planningto use a peer-to-peer application in Bluetooth, like two PDAs in a chatsession, then either device would use device discovery to find the other de-vice. In case we are planning to use a client-server type application, likeprinting from a lap-top to a printer, then the client is most likely to per-form device discovery. It doesn’t make sense for the printer to constantlylook for devices that want to print something. Now, let’s take a look atthe two classes needed in order for the Bluetooth device to discover remoteBluetooth devices in the area: DiscoveryAgent and DiscoveryListener.

5.5.1 Discovery Agent

After getting a LocalDevice object, the most logical next step for devicediscovery is to instantiate the DiscoveryAgent object. This can be achievedby invoking LocalDevice.getDiscoveryAgent().

LocalDevice localdevice = LocalDevice.getLocalDevice();DiscoveryAgent discoveryagent = localdevice.getDiscoveryAgent();

When it is required to discover other Bluetooth devices in the vicinity,DiscoveryAgent gives two possibilities to do the work with: startInquiry()and retrieveDevices().

5.5.2 Discovery Listener

In the course of working with event handling in Java, then the concept oflisteners is no more a dilemma. Similar to all listeners, DiscoveryListener isan interface that has a method that is called by the JVM when the desiredevent occurs. In the case we want to be informed when a Bluetooth device isfound by DiscoveryAgent.startInquiry(), then the class needs to implementthe DiscoveryListener interface. Every time a Bluetooth device is located,the method deviceDiscovered() is called or invoked

5.6. SERVICE DISCOVERY 31

5.6 Service Discovery

After locating the devices in the vicinity, it would be possible that the Localdevice sees different services offered by other devices. It is evident that onecan always inspect the DeviceClass object, but that may only reveal half thepicture. For instance we may want to print a text file. It is obvious, that ifthe DeviceClass indicates that the major device class of the RemoteDeviceis a printer, then the settings are correct. Another question that pops up iswhat happens if the major device class is a computer? Is it possible to alsoprint to a computer that is acting as a print server?This can be resolved by the service discovery-related classes in the JavaBluetooth specification that implements the Service Discovery ApplicationProfile. The Service Discovery Application Profile, in turn, uses the ServiceDiscovery Protocol (SDP) layer in our Bluetooth stack to find services onremote Bluetooth devices.

In the Java Bluetooth specification for service discovery the followingclasses are provided: DiscoveryAgent, DiscoveryListener, ServiceRecord,DataElement, and Universally Unique Identifier (UUID). There is also anindirect interaction with the The Service Discovery Database (SDDB) when-ever one needs to discover services on a remote Bluetooth device.

5.6.1 The Service Discovery Database

The Service Discovery Database (SDDB) in Figure 5.2 [22] is the centralrepository for all service records, unlike the database in the sense of Oracle9i, Sybase, or even MS Access. It’s merely a collection of service records.The JSR-82 implementation is free to implement the SDDB in any form,so as soon as a ServiceRecord object is stored in the SDDB, it doesn’tnecessarily mean that the JVM serialized the ServiceRecord object andstored it in a data store. If a particular JSR-82 implementation does notstore service records in the SDDB as Java objects, then it must convertthem into ServiceRecord objects whenever a client performs a search forservices and a match is found.

5.6.2 Service Record

ServiceRecord objects are representations of individual entries in the SDDB.It is worth remembering that the SDDB is the central repository of servicerecords for a Bluetooth device.


Figure 5.2: The Service Discovery Database (SDDB)

5.7 Data Element

Breaking through the anatomy of service discovery, pave the way to nowexamine the DataElement object. Each ServiceRecord object in the SDDBis made up of attributes. All attributes are stored as DataElement objects.A DataElement object can be from any of the following:

• Integers

• Booleans

• Strings

• UUIDs

• Sequences of the preceding values

5.8 Service Registration

Before a Bluetooth client device can use service discovery on a Bluetoothserver device, the server needs to register its services internally. That pro-cess is called service registration.The scenario or getting the service registered and stored in the SDDB areas follow:

1. Call Connector.open() and cast the resulting connection to a stream-ConnectionNotifier Object Connector.open() creates a new ServiceRe-cord and sets some attributes.

5.9. COMMUNICATION 33

2. Use the LocalDevice object and the streamConnectionNotifier to ob-tain the ServiceRecord that was created by the system.

3. add or modify the attributes in the serviceRecord (Optional)

4. Use the StreamConnectionNotifier to call acceptAndOpen() and waitfor Bluetooth clients to discover this service and connect.

5. The system creates a service record in the SDDB. Wait until a clientconnects. When the server is ready to exit, call close() on the Stream-ConnectionNotifier.

6. The system removes the service record from the SDDB.

It is important to mention here that the StreamConnectionNotifier andConnector both come from the javax.microedition.io package of the J2MEplatform [23].

5.9 Communication

Bluetooth is a communication protocol in Figure 5.3 [22]. So how is itpossible to communicate with? the Java Bluetooth API provides threeways to send and receive data, nevertheless we consider here only two ofthem: RFCOMM and L2CAP.RFCOMM is the protocol layer that the Serial Port Profile uses in order tocommunicate. Unlike RFCOMM connections, which are stream oriented,L2CAP connections are packet oriented.

5.9.1 L2CAP versus RFCOMM

Owing that there is a provision to send data between Bluetooth clientsand servers using both L2CAP and RFCOMM, there is still a dilemmaabout typical usage scenarios for these connections. In other words, whywould anyone use RFCOMM instead of L2CAP to send data or vice versa?To clarify this situation it is important to outline that, RFCOMM is alsoknown as the virtual serial port communication protocol. An ideal way touse RFCOMM is in situations when one needs to replace a serial cable.For instance, if we were a developer for a Global Positioning System (GPS)manufacturer, and our duty was to make one of their units Bluetooth en-abled, then RFCOMM would be no doubt a choice in this scenario. The


Figure 5.3: The Generic Connection Framework and Bluetooth ConnectionTypes

reason here is that the GPS unit will always have a constant stream of in-formation that needs to be processed, rendered, calculated, etc. So, collectthe data from our stream and plot those coordinates on the screen. On theother hand, L2CAP is great for handling packet data. L2CAP can easilybe used (and actually is) as a data multiplexer. It is possible to read datafrom the connection, and based upon a header in the packet, one can routethat data to different methods, threads, and classes in our application.

5.10 Summary

This chapter outlined some formal introduction to the Java Bluetooth APIs.It also outlined all the basic components of a Bluetooth application, as wellas how to implement them using the classes and interfaces of the JavaBluetooth API. It also discussed the importance and the roles that theBCC plays in wireless applications. Finally, it showed how a Bluetoothapplication works by its components

Chapter 6

Design and Implementation

After gathering necessary resources such as services and protocols via Blue-tooth Technology in earlier parts of this report, in this chapter will takeplace the implementation phase.

6.1 Requirements

The Client & Server architecture is used in this project in order to imple-ment the short range wireless intelligent network according to [24]. There-fore making the rapprochement with Bluetooth technology for implementingsuch network there must be a Master& Slave. Where the master will actas client and the server as slave. Moreover some requirements such as JavaMessage Service (JMS) that have to be designed according to the Figure 6.1.

The Bluetooth enabled devices are required for implementing as in [25]the short range wireless network. In the specific case of the thesis, theBluetoots devices are: Bluetooth enabled Laptop acting as slave, and theBluetooth enabled Mobile (Nokia 5300) acting as the master. Why Nokia?Simply because Nokia phones bluetooth reaches longer distance than SonyEricsson. It is important to mention here that the mobile is master be-cause it is the one sending command to the Laptop via Bluetooth port forexecution.

35

36 CHAPTER 6. DESIGN AND IMPLEMENTATION

Figure 6.1: Conceptual Model for Java Message Service.

6.2 Components Architecture

Figure 2.1 depicts the "BlueClient" and the "BlueJ2seServer" connectionarchitecture which are the two main part of the design phase accordingto [26]. It can be noticed from the same figure that the two block (Blue-tooth enabled device) have virtual peer communication between them. The"blueJ2Server" consists of Helpers, Commands Executer and finally theservices and the "Blueclient" consits of Helpers, Messages Board, and theRemote Control.

The Helper typical diagram is shown in Figure 6.2 consists of BlueAgent,Receiver, MessageListener and Sender. The helper plays a vital role in theBluetooth communication such as service interpreter.

6.3 Design

In order to design a short-range wireless connectivity, some requirementsmust be met prior to it implementation according to [27].

This project has been designed on JAVA platform. In order to supportdevelopment of Bluetooth-enabled software on the Java platform, the JCPhas defined JSR 82, the JABWT.

The Java APIs for Bluetooth is a Java Micro Edition specification forAPIs that allow Java MIDlets described in section 5.2 to use Bluetooth on

6.4. IMPLEMENTATION 37

Figure 6.2: Typical Helper architecture

supporting devices. The specification was developed under the Java Com-munity Process as JSR 82.

For the Client (Blueclient), the Bluetooth enabled Nokia phones hasbeen preferred in this project for the simple reason that it reaches longerdistance than Bluetooth enabled Sony Ericsson does. On the other hand anyBluetooth enabled PC or Laptop has been used as server (Bluej2seServer).

6.4 Implementation

The algorithms have been implemented according to two main blocks as inFigure 2.1: in one hand "Bluej2seServer.java" together with Helpers con-sisting of "BlueAgent.java", "Receiver.java", "MessageListener.java" and"Sender.java" for the server block and on the other hand "Blueclient.java"consisting of "BlueAgent.java", "Receiver.java", "MessageListener.java" and"Sender.java" on the client block.

After writing all the source code, the "Blueclient.java" in then down-loaded Bluetooth port to the Nokia 5300 acting as a client. For properoperation both client and server must be turned on. The Helpers will han-dle communication (services or connection) between peer blocks.


Figure 6.3: BlueJ2seServer initialization screen-shoot

Let’s take for instance the scenario when a client request either a serviceor a connection to the server. The procedure will follow the same pasternas described in Section 5.5. Therefore according to the diagram of Fig-ure 2.1 the sender from client end sends a request to the receiver in serverend, that is intercepted by the Message Listener of the same end which inturn sends the Command executer to the services in order to process therequest.

When the request is done, services sends back the response to the Com-mand Executer which in his turn sends to the sender for transmission tothe Client’s Receiver. It is worth mentioning here that Message Listenerson both end are always in the sniffing mode to see if there is any requestto be processed provided that the Bluetooth devices are on. They also actlike service notifiers for the Bluetooth.

6.5 Testing

During the testing phase, I have turned on the "BlueJ2seServer", then en-ter the initialization phase as shown with the screen shoot depicted in Fig-ure 6.3.

6.6. SUMMARY 39

Figure 6.4: BlueClient and BlueJ2seServer pairing screen-shoot

Then after the first step turned on the "BlueClient" and they startedpairing together with the "BlueJ2seServer" as shown on Figure 5.3.

After the pairing completed the "BlueClient" can start sending the re-quest or command to the "BlueJ2seServer" for execution. The Helpersdepicted in Figure 6.2 is very useful here and plays the role of informant toboth "BlueJ2seServer" and "BlueClient".

Completed executing all the task the "BlueClient" send a "ShutDown"command to the "BlueJ2seServer", this in order to save power anyhow.Hence complete my generic project test.

6.6 Summary

In this chapter, a laptop computer (acting as slave) and a mobile phone(acting as master) all bluetooth enabled have been used for simulation pur-pose. The services simulated are programs available on the Laptop that canbe accessed from a mobile phone. The simulation results are presented interms of computer screen-shoot.


Figure 6.5: BlueJ2seServer Executing BlueClient’s commands screen-shoot

Figure 6.6: BlueJ2seServer Executing "ShutDown" Command issued byBlueClient screen-shoot

Chapter 7

Conclusion and Future Research

7.1 Conclusion

The connectivity issue raised is a main challenge, still the emphasis has beenput on enable devices to communicate according to the services. Hence theservice oriented architecture has been discussed in Chapter 2 where SOAuse and reuse of components makes it easier to build new applications. Af-ter this conceptual point of view the focus was to sort out a reliable and costeffective technology for designing a reliable and cost effective short rangewireless network in Chapter 3. Due to the presence of many candidatetechnologies the unanimity seems to favor the bluetooth that fits well thegap. Then follow different scenarios or real time application are presentedin Chapter 4.

After all the information and tools gathered altogether, comes the timeof action put the pieces together using the JABWT discussed in Chapter 5.It is worth mentioning that the JABWT is used to connect the client andserver according to the specification JSR 82 developed under the JCP. Thecrucial part at the center stage of this thesis is the network architecturefollowing the design and implementation phase in Chapter 6.

There are two key advantages to using the official Java Bluetooth APIversus a C-based (or native) API:

• API is independent of the stack and radio

• Standardized Bluetooth API

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42 CHAPTER 7. CONCLUSION AND FUTURE RESEARCH

Some hidden important components involved during the Bluetooth pair-ing process such as Helpers discussed elaborately in Section 6.1. The equip-ments used for this testing were A mobile phone and a Laptop all bluetoothenabled. At the end of the day the outcome was a bit satisfactory thoughstill long way to go in order to get full satisfaction. Therefore the followingsection will highlight some areas that need to be given attention.

7.2 Devices of the Future

In the near future, Bluetooth wireless young technology will certainly seea fair amount of evolution, with ultimate goal such as the creation of truead-hoc networks, self-configuring network groupings that grow and changeas the user’s environment changes.

For Bluetooth technology to be successful in the long run, it will alsohave to deal with issues like discovery time (currently far too slow) andmaximum throughput (to align with 3G technologies). Consequently, whatkind of devices, applications, or innovations can we expect to see in thefuture that involve Bluetooth?

Prior to dealing with some future innovation, it will be better off to havea broad view of how best the short range wireless technology will fit in ourenvironment. The following are some few areas that we can think of:

• Bluetooth locator system

• Personalized family car

• The new arcade: a restaurant lobby

7.2.1 Bluetooth Locator System

A the Bluetooth locator system will display house’s a map as well as locatelost items in the room. This solution is ideal for people who always misplacesmall but essential items like PDAs, wireless phones, keys, TV remotes,watches, and baby pacifiers.

7.3. FUTURE RESEARCH 43

7.2.2 Personalized Family Car

Another future area of interest is the Bluetooth-enabled car, where all pref-erences such as he mirrors, seats, and radio stations are customized (or justset once) then store on a Bluetooth enabled device such as wireless phone,PDA, or a watch for future use just by turning it on. It wouldn’t matterif someone else used your car, since all your preferences are stored on thedevice. After someone uses the car, preferences could be uploaded fromBluetooth enabled device.

7.2.3 The New Arcade: A Restaurant Lobby

Finally, let’s assume another area of interest for the future such as a Bluetooth-enabled device acting as a restaurant lobby that could be used in one handto play games against the computer, or other people in the lobby on theother hand as an alert (automatic vibration) that the table is ready, so thehostess doesn’t even need to call me.

The examples as aforementioned are not exhaustive for future area ofinterest. The importance of the short range wireless network in life is hugesince applicable in many area of interest, therefore one may say that it stillhas a bright future with some innovative services coming in the near future.

7.3 Future Research

The future of communication (wireless) systems could be somewhat un-predictable. General requirements for the future communication systemswill mostly be derived from various services a user will need in the future.Nevertheless, those future services including application scenario are stillundefined. However, some key elements of future communication systemsmight be assumed and research trends defined.

Merging from the earlier experiences and knowledge, mainly from theBluetooth platform as mentioned in previous chapter, the development ofintegrated solution must take into consideration the following points:

• Interoperability with the existing networks,

• Scalability according data rates, cost, power and device functionalities

44 CHAPTER 7. CONCLUSION AND FUTURE RESEARCH

• Multimode functionality (access to multiple networks)

• Distributed resource allocation (with QoS provisioning)

• Service discovery

• Ad-hoc behaviour and self-organization

• Security.

In order to make this vision become a reality, an adaptive short rangewireless network has to be deployed, with aim to providing flexible, adapt-able, and secure, end-to-end communication and information services for:

• Small connections (to home and businesses);

• Smaller connections within homes, PANs, and among microrobots forinstance.

Bibliography

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[9] D. Kaye, “Loosely CoupledŮThe Missing Pieces of Web Services”, RDS Press2003. [cited at p. 7]

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[11] S. Michael, “Using Architectural Patterns and Blueprints for Service-OrientedArchitecture,” IEEE Computer Society (2006). [cited at p. 8]

[12] M. Endrei, J. Ang, A. Arsanjani, S. Chua, P. Comte, P. Krogdahl, & M. Luo,“Newling Patterns: Service Oriented Architecture and Web Services”, IBMRedbook, 2004. [cited at p. 9]

[13] M. Endrei et al., “Patterns: Service-Oriented Architecture andWeb Services”,IBM, 2004. [cited at p. 10]

[14] D. Schmidt et al., “Pattern-Oriented Software Architecture Patterns for Con-current and Networked Objects”, John Wiley & Sons, 2000. [cited at p. 10]

[15] S. Michael, “The Bluetooth Radio System,” IEEE Personal Comm, 2000.[cited at p. 14]

[16] S. Michael, “Networked MIDlets Using Bluetooth,” Forum.Nokia.com, 2004.[cited at p. 14]

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[24] P. Bhagwat, C. Bisdikian, I. Korpeoglu, A. Krishna, & M. Naghshineh,“System Design Issues for Low-Power, Low-Cost Short Range Wireless Net-working,” IBM Thomas J. Watson Research Center, New York,IEEE, 1999.[cited at p. 35]

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Index

API, 36

BCC, 28, 34

CCK, 15CoD, 29

DSL, 15DSSS, 15

FHSS, 14FTP, 21

GPS, 33

HTTP, 21

IMAP, 21IrDA, 14, 16, 17, 19

JABWT, 36, 41JCP, 36, 41JMS, 35JVM, 29–31

MIDlet, 36

OFDM, 15

PDA, 13, 16, 21–25

SDDB, 31–33SDP, 31

SMTP, 21SOA, 7, 8, 10, 11

USB, 24UUID, 31, 32

WLAN, 14, 15, 17, 18, 23

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