Bluetooth Demystified

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The use of different frequency-hopping schemes minimizes the chance of interference, as does spreading over the entire fre- quency band. Safety Radiation emissions from devices using Bluetooth wireless technology are no greater than emissions from industry-standard cordless phones. The Bluetooth module will not interfere or cause harm to public or private telecommunication network equipment, nor jeopardize the safety of the consumer using the equipment or those who come with- in the operating distance of Bluetooth devices.

Personal Area Networks One of the major goals shared by the IEEE afrd the Bluetooth SIG is the global use of wireless personal area networks PANs l The IEEFs working group is looking at creating standards that will pro- vide the foundation for a broad range of interoperable consumer devices by establishing universally adopted standards for wireless dig- ital comm un i cation s.

The goal of the working group is to create a consensus stan- dard that has broad market applicability and deals effectively with the issues of coexistence with other wireless networking solutions. While the IEEE wireless LAN technologies are specifically designed for devices in and around the office or home, devices using the IEEE ,15 wireless PAN and Bluetooth wireless technology will provide country-to-country usage for travelers in cars, airplanes, and boats.

The master is the device in a piconet whose clock and hop- ping sequence are used to synchronize all other devices ii. The unit that carries out the paging procedure and estab- lishes a connection is by default the master of the connection. The slaves are the units within a piconet that are synchronized to the mas- ter via its dock and hopping sequence. The Bluetooth topology is best described as a multiple piconet structure. Piconets are uncoordinated, with frequency hopping occurring inde- pendently. Several piconets can be established and linked together ad hoc, where each piconet is identified by a different frequency hopping sequence All users participating on the same piconet arc synchronized to this hopping sequence.

With its service discovery protocol, the Bluetooth specification enables a much broader vision of networking, including the creation of Personal Area Networks, where all the devices in a persons life can communicate and work together Figure F9. Technical safeguards ensure that a cluster of Bluetooth devices in public places, such as an airport lounge or train terminal, would not suddenly start talking to one another.

Bluetooth wireless technology can scale upward to sup- port wireless data transmission applications operating in the 5-GHz range, supporting connections to devices up to feet away. Security Worried about security? Don't be — the Bluetooth specification includes several security features.

In addition to its limited range and its use of frequency hopping, which makes signal interception extremely difficult in the first place, the Bluetooth specification employs such link-level functions as authentication and encryption. Encryption scrambles the data during transmission to prevent eavesdropping and maintain link privacy. In addition, Bluetooth wireless technology includes session-key genera- tion that can be changed at any time during a connection. Even in the unlikely event that a hacker is able to grab a connection, he or she will not be able to stay on a piconet for any length of time.

Security is important not only to ensure the privacy of your mes- sages and files as they fly through the air, but to ensure the integrity of electronic commerce transactions as well. Under the Bluetooth security architecture, untrusted or unknown devices may require authorization based on some type of user interac- tion before access is granted.

Trusted devices are those that have been previously authenticated and allowed to have access based on their link-level key. For these devices, the link key may be stored in the Chapter 1 device database, which identifies that device as trusted in terms of future access attempts. The security architecture of the Bluetooth specification only authenticates devices, not users, This means that a trusted device that is stolen or borrowed can be used as if it were still in the possession of the rightful owner If there is a need for user authentication, supple- mentary application-level security methods must be employed, such as the entry of a username and password, as would be the case if the device were to be used for mobile e-commerce transactions.

The Bluetooth specification enables you to connect a wide range of computing and telecommunications devices easily and simply, without the need to buy, carry, or connect cables. It will provide opportunities for rapid ad hoc connections, and make possible automatic connections between devices. It will virtually eliminate the need to purchase addi- tional or proprietary cabling to connect individual devices. Because Bluetooth wireless technology can be used for a variety of purposes, it also replaces multiple types of cable connections with a single radio link.

Presentations Setting up a PowerPoint presentation, for example, would no longer require a spaghetti-like tangle of cables between projector, laptop, and printer. You would simply place the laptop near the projector, turn them on, and wait a few moments for them to communicate the nec- essary operating parameters Via the same radio link, the laptop could send print requests to a nearby printer, allowing distribution of the latest reference materials to attendees For small groups, the presenta- tion can be delivered to each attendee's laptop that is using Bluetooth wireless technology.

This would permit meetings to be held in any room, without requiring a projection screen, special lighting controls, or seating arrangements The Case for Bluetooth 27 Card Scanning With a business-card scanner using the Bluetooth specification, you can scan cards into your own computer or any other computer within the foot range without having to go through the hassle of connecting, discon- necting, and reconnecting cables between machines.

Since the business- card scanner may not be used very frequently, significant cost savings can be achieved by sharing the device wirelessly among a group of users. Collaboration With special software that turns notebooks, palmtops, or Windows CE devices using Bluetooth wireless technology into a sketchpad, you can use a stylus as the input device to annotate or draw on Word files, e-mail messages, JPEG photographs, or any Windows-based applica- tion.

The changes remain on screen, allowing the marked-up docu- ment to be saved on each device or e-mailed as an attachment. Synchronizing Data A neat tricks that Bluetooth devices can accomplish is sending mes- sages to devices that are powered off or in sleep mode. For example, when a cell phone receives a message, it can send it to a laptop com- puter, even if the latter is packed in a briefcase and powered off. Of course, the technology can also be used for synchronizing data between the devices, ensuring that the most current version is avail- able, regardless of what device you happen to select Figure 1.

Automatic synchronization can be a real time saver. When you leave the office, any new files added to your desktop PC are automatically copied to the palmtop. When you arrive at home in the evening, the palmtop automatically loads the new information to your laptop as soon as the two devices come within range. You do not do anything — link-up just happens. Figure 1 ,9 When Bluetooth devices are set up properly they can communicate within a 30 -fooE range and synchronize fifes without explicit commands. Back at the office, your boss sends the changes from her workstation to your cellular phone, which automatically con- nects to your organizer and updates the schedule.

The next time you power up your organizer, you are immediately alerted to the change. By eliminating hard connections, the Bluetooth specification erases the difference between mobile and stationary computing — the devices are "plugged in" wherever they happen to be. On a train, for example, Bluetooth wireless technology would enable you to connect a laptop or palmtop to the Internet via a cell phone in your briefcase, while at the office, the link would be through an access point provid- ing a wireless connection to the corporate LAN. Printing Consider slightly more far-out scenarios, too: In-Car Systems In the near future, the Bluetooth specification will allow a range of digital devices to share information wirelessly within an auto- mobile — everything from cellular phones and pagers to hand-held computers and more.

Among the companies offering such systems is Johnson Controls. The company's TravelNote Connect is a modified TravelNote digital recorder that integrates Bluetooth wireless technology. By adding a Bluetooth wireless technology component, the device can do things like get a phone number from a handheld phone and auto- matically dial it so the driver doesn't have to take his or her hands off the wheel. When the connection is established, the Bluetooth comp- nent sets up a wireless voice link with the cellular phone, providing hands-free, speakerphone capabilities. This and similar products from other manufacturers have the capacity to make every cellular phone a hands-free phone in the near future, without complex retrofits or costly installations in a vehicle interior.

Since any device using Bluetooth wireless technology can talk to any other similarly equipped device, products can be mixed and matched for use in the car, irrespective of model, brand, manufactur- er, or operating system. Communicator Platforms Communicator platforms of the future will combine a number of technologies and features in one device, including mobile Internet browsing, messaging, imaging, location-based applications and servic- es, mobile telephony, personal information management, and enter- prise applications With these integrated mobile information devices.

Ericsson is among several companies that will offer integrated com- municator platforms capable of supporting high-speed data transfer triple-band voice, and Internet access. The user interface is based upon the VGA format Figure , which Ericsson believes is an ideal size for mobile communications devices and applications. The device has a color touch screen, which allows for easy navigation, pen input, and handwriting recognition.

With a built-in GPS receiver, the platform can provide positioning information. With built-in Bluetooth and infrared components, the platform can connect wirelessly with other devices, networks, and third-party applications. Electronic Books With electronic books becoming popular, you can purchase titles on the Web from online booksellers and download them to your desk- top or notebook computer. In essence, your computer becomes an electronic library from which you can select specific electronic vol- umes to take with you on business trips or vacations.

It features a white back light for easy text viewing. Once these ebooks are enhanced with Bluetooth wireless technology, you will be able to transfer preselected titles between the devices merely by placing the ebook within range of the computer holding your library Figure 1. You can arrive at the air- port and buy a ticket simply by walking past a wireless terminal, which confirms your identity, issues an electronic ticket, and bills your credit card. A flight attendant would no longer have to visit pas- sengers and ask them to turn off their electronic devices. After the request is broadcast, the airplanes master Bluetooth device would shut down all electronic devices automatically for takeoff and landing.

Chapter 1 After landing in your destination city, you get on the rent-a-car bus at the airport Your reservation is automatically transferred to the rent-a-car database where it is verified, so the bus driver can let you off at your pre-assigned can When you get in the rental car, which is equipped with Bluetooth wireless technology devices, your hotel reservation is automatically queried from your palmtop or cell phone and the Global Positioning System GPS provides you with on-screen directions to your hotel. As you enter the lobby, you are automatical- ly checked in, and your room number and electronic key are auto- matically transferred to your Bluetooth device.

As you approach the room with bags in hand, the door automatically opens. Later, if you can't fall asleep right away, you can catch up on some reading by breaking out your ebook. Home Entertainment If you think all this is far-fetched, Microsoft envisions the day when you can buy a fitted with Bluetooth wireless components digital TV that will call you when your favorite football team is about to kick off and ask you if you want to record the game.

In the home, there are myriad applications for Bluetooth wireless technology. Imagine a simple data pad equipped with a Bluetooth transceiver and a touch-screen display. The data pad is slim, light- weight, and, with an advanced icon-driven menu, easy to use. The data pad will not only control all the entertainment devices in the home, but also control new ones that may be purchased in the future, final- ly putting an end to the proliferation of infrared remote controls.

According to Microsoft you might even be able to enhance your bathroom with special Bluetooth chips that monitor toothpaste and soap, and remind you to buy more when levels run low. Bluetooth wireless technology could be used in a sim- ilar way for rail fares, cinema tickets, parking fees, and other every- The Case for Bluetooth 33 day purchases at kiosks — making for less hassle for consumers and lower transaction costs for companies Figure 1.

With the addition of Bluetooth wireless components, such phones will provide users with even more flexibility. Scanners Bluetooth wireless technology also encourages the development of entirely new products. The device cap- tures text or graphics via a tiny scanner and stores information in its S MB of onboard memory. The C Pen offers a range of palmtop-like features. For example, one feature allows the user to scan in a business card, line by line, and then upload it to a contacts database in Microsoft Outlook.

Two-way language dictionaries let you translate, for instance, from English to German and vice versa. One version of the C Pen has a built-in Bluetooth wireless port, while another version has an infrared port for communicating with other computers. The company expects to release a version of the C Pen that uses both infrared and Bluetooth wireless technology.

The gadget boasts a MHz Intel processor plus a 3-hour battery, yet it is still small enough to fit in the hand. Chapter 1 Behavior Enforcement Bluetooth wireless devices can be combined with other technologies tp offer wholly new capabilities, such as automatically lowering the ring volume or shutting off cell phones as users enter quiet zones. The convenience and potential benefits of cell phones are indisputable, but the technology's near ubiquity is provoking heated discussion about when and where they should be used With more than 80 mil- lion cell phone subscribers in the US.

Bluetooth wireless technology can be used to enforce courteous cell phone usage in designated quiet areas, allow- ing users to keep their phones handy without compromising their good manners while theaters and meeting planners can provide the quiet atmosphere their patrons have come to expect. It operates through a series of small nodes installed throughout the quiet zone that form a short-range wireless network i,e, piconet , which allows seamless com- munication between the different devices. Mobile E-commerce Bluetooth wireless technology will play a key role in electronic com- merce.

Soon you'll be able to avoid the line at retail stores to pay for items, or access the Internet anywhere via your mobile phone to order and pay for goods and services.

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Up to eight interconnected devices can be sup- ported by a piconet, with one master and up to seven slaves. Also, once an infrared device is connected to the LAN, it must remain relatively stationary for the duration of the data session. In the home, there are myriad applications for Bluetooth wireless technology. As the project progressed, it became clear that the applica- tions for a short-range radio link were virtually unlimited Ericsson s work in this area caught the attention of IBM, Intel, Nokia, and Toshiba. Each slave adds an offset to its native clock to get in step with the master clock. In synchronous transmission, data goes out over the link as a con- tinuous stream of bits. Don't be — the Bluetooth specification includes several security features.

While some mobile phones already have smart cards he. Bluetooth components will allow the smart card to be read while it remains in the phone or palm- top device Figure 1. The Case for Bluetooth 35 Figure 1. Both sizes are offered together to fir any kind of mobile phone the user happens to have. The is compatible with the Bluetooth specification and card includes the Bluetooth protocol stack for Windows CE. Ericsson and Visa International are among the companies develop- ing payment solutions for the purchase of goods and services over the Internet through mobile devices, including cell phones and palmtops.

The wireless wal- let, which can serve as a replacement to a conventional wallet for bills and coins, contains multiple smart card readers. A smart card inserted into the wallet can communicate with a mobile device using Blue- tooth wireless components. The mobile device can be used for Inter- net shopping so that the appropriate smart card in the wireless wallet is used for payment.

SET was developed by Visa and other payment industry and tech- nology companies as an open, global standard for secure electronic commerce. Based on encryption technology developed by RSA Data Security, it allows cardholders and merchants to use special encoding and identification software, called digital certificates, to authenticate themselves to each other and to allow cardholders to safely send cred- it card numbers over the Internet as payment EMV is a joint industry initiative to facilitate the introduction of chip technology into the international payment systems environment by developing joint specifications for Integrated Circuit Cards ICC and terminals for payment systems.

EMV serves as the global frame- work for chip card and terminal manufacturers worldwide. Industry studies predict that within the next 10 years, consumers will increasingly rely on non-PC devices such as the mobile phone to access the Internet This partnership will ensure that Visa member banks will be able to offer cardholders secure payment solutions for the purchase of on-line goods and services with a mobile phone. The advent of Web-enabled mobile phones allows users to access the Internet and receive messages over the air.

This provides Visa and its member banks with a new opportunity to offer convenient and exciting services to cardholders on the go. An example of a new service made possible by this technology is the targeted promotion of concert or theater tickets. This service will make it possible for mobile-phone subscribers to be notified of an event before the tickets are sold out The user can purchase the tickets immediately over the Internet using a Web-enabled mobile phone that supports the wireless access protocol WAP.

The tickets are then sent electronically to the phone, where they are stored on a smart card.

When the user arrives at the theater, the electronic tickets on the The Case for Bluetooth L 3T smart card are presented via the Bluetooth wireless connection estab- lished with the theater's pointof-sale terminal WAP is an open global specification that enables mobile devices to access and interact with Web-based information and services. It pro- vides the middleware necessary that runs on top of the Internet Proto- col IP , enabling the delivery of text content to wireless terminals. Among the common information servic- es that are delivered in this way to WAP-compliant portable devices are news items, sports scores, airline schedules, weather and traffic reports, local restaurant and movie listings, and stock quotes With Bluetooth wireless technology, merchants as well as the bank- ing and finance industry will be able to generate increased revenues.

In exploiting the full market potential of mobile commerce and expanding secure, mobile e-commerce solutions, participating compa- nies of all types and sizes can open up new business opportunities In this regard, the Bluetooth specification represents a completely new dimension to e-commerce that will radically change how portable and wireless devices are viewed and used. It provides endless opportunities for applications such as vending and ticketing machines, point-of-sale terminals, banking machines, and parking meters.

Java and Bluetooth Most current mobile devices are based upon proprietary platforms such as Microsoft's Windows CE or PalmOS, and cannot share applica- tion drivers or peripherals. This situation does not bode well for the acceptance of the Bluetooth specification, since one of the key advan- tages of the technology is ad hoc networking with devices that may be encountered spontaneously.

This automatically makes all Java programs cross-platform applications. This method of code deployment also makes Java better suited for the memory-constrained embedded devices equipped with Bluetooth Wifeless technology. Chapter 1 There are two other compelling reasons for using Java in embed- ded systems: In the second case, the company's software development team bene- fits from an elegant programming language for all code, from drivers to applications. While Java will not turn anyone into an embedded software expert, it can make both senior and junior firmware design- ers more productive.

Rapid development is facilitated through code reuse, so embedded systems are easier to test and faster to deploy. Wireless devices natively executing Java code will be able to communi- cate spontaneously and interact with other Java-enabled devices through various wireless protocols. In addition to the Bluetooth specification, HomeRF and are also expected to extend wireless capability to these types of devices Jini and Bluetooth In addition to Java, Sun offers a service discovery technology called Jini. Built on Java technology, Jini is designed to enable users to make simple connections to other devices.

When two J ini-enabled devices come within range, they automatically detect each other, exchange capabilities information, and establish a network connection. As described by Sun, devices using Jini technology employ a discov- ery process to seek out other devices that also use Jini technology. The devices then post objects — representing the services they provide as 4 Sun offers a small footprint version of the Java Virtual Machine for severely memory- constrained environments of 12S KB to M2 KB.

The K Virtual Machine KVM is designed specifically for consumer and embedded devices and is part of a larger effort on the part of Sun to provide a modular, scalable architecture for the development and deployment of portable, dynamically downloadable, and secure applications in consumer and embedded devices This larger effort, called the Java 2 Platform Micro Edition Java 2 ME , is optimized for small-memory limited-resource connected devices such as cellular phones, pagers, PDAs, television set-top bom, and point-of-sale termmak The Case for Bluetooth well as their defining characteristics and attributes— to a Jini technol- ogy lookup service.

When a device wants to use a service offered to the community, it can download the required objects, including any code such as applications, device drivers, or user interfaces, from the Jini technology lookup service. To understand how Jini technology complements Bluetooth wire- less technology, consider how a picture taken with a digital camera might be printed Figure 1.

The print- ing service typically will be performed locally; but sometimes, as shown on the right, the service may either need to communicate with an external device, such as an older printer that does not support the Java programming language, or else bridge to a foreign device i. In this case, the service consists of printing a picture from a camera. The arrows indicate the different levels of communication that arc required to print the picture.

First, the camera locates the printer serv- ice by using Jini technology, which in turn uses whatever network protocol is supported by the operating system. Jini technology docs Chapter 1 not require any particular operating system or network transport: This code uses the underlying network rans- port — that of the Bluetooth architecture or any other network trans- port protocol — to implement the printing service protocol needed to transmit the picture to the printer. At this writing, Jini's future is in doubt t Other Connectivity Solutions In addition to Bluetooth and infrared wireless technologies, there are other emerging network technologies that have their own protocols to locate and communicate with devices over wireline or wireless links, Examples include JetSend and HAVi JetSend JetSend technology, developed by Hewlett-Packard and available since , is an example of a service protocol that allows devices like print- ers, digital cameras, and palmtop computers to negotiate information exchange intelligently, over wireless links, with no user intervention.

With digital cameras, for instance, real photos can be as dose as your The Case for Bluetooth computer — just point and shoot — and your photos are transferred to your desktop computer, or sent to a printer for output on photo- quality paper. Or you can use JetSend to send the photos wirelessly to your palmtop computer or other Windows CE device. The JetSend protocol allows the devices to identify a common data format and exchange data, eliminating the need for special drivers to make all devices work together. Currently, JetSend devices can com- municate wirelessly over infrared links at 4 Mbps, but there is no rea- son why the protocol cannot support Bluetooth wireless links, as the technology becomes more popular in the future.

In essence, HAVi will let these devices recognize one another and link up in a home network — without the use of a PC. The network configura- tion is automatically updated as devices are plugged in or removed Applications are expected to coordinate the control of several devices and to simplify the operation of devices by the user. Matsushita hopes to offer a set-top box that allows you to sift through hundreds of channels and record the programs you select In a few years, the boxes may be able to guide the storing of hours of content and allow you to use a search engine to navigate through it IEEE cable, also known as FireWire, is used to connect devices at , , or Mbps on the HAVi network.

With HAVi, a bridge proto- col would be required to provide a way to share services between HAVi devices and devices using Jini technology. Applications using Jini soft- ware can gain access to HAVi devices such as VCRs In similar fashion, home devices on the HAVi network, specifically televisions, could con- nect to remote Jini-enabled services such as video-on-demand Microsoft has another scheme to take control of your living room.

HAVi advocates claim Microsoft operating systems are not suited to consumer electronics because they are too complex, bug prone, and unable to cope with large continuous data streams.

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These emerging network technologies play key roles in making impromptu digital networking become a truly universal, instantly accessible, and reliable method of device interconnectivity. The list of innovations doesn't stop here. At the macro level, there is the emerging global 3G network to consider.

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Global 3G Wireless Framework The Bluetooth wireless technology specification is one of the tech- nologies being developed to optimize the use of third-generation 3G mobile multimedia communications systems being developed by the International Telecommunication Union ITU and regional standards bodies. Under this "family of systems" concept, various wireless tech- nologies are unified at a higher level to provide users with true global roaming and voice-data convergence, leading to enhanced services and innovative multimedia applications.

This initiative, called Internation- al Mobile Telecommunications IMT , encompasses both satellite and terrestrial systems, serving fixed and mobile users in pub- lic and private networks. The role of the ITU is to provide direction to and coordinate the many related technological developments in this area to assist the conver- gence of competing national and regional wireless access technologies.

With a set of universally accepted specifications, all national and regional equipment manufacturers can build systems and products that interoperate. As a global standard, the Bluetooth specification feeds into this 3G framework very nicely. Among the possible 3G support applications for which Bluetooth wireless technology might be suited is local intercommunication as well as wide area connectivity, to provide a greater level of service than either could achieve separately.

The Case for Bluetooth 43 Take vending machines at a shopping mall, for example. Through a Bluetooth access system, a cluster of automatic vending machines can be connected to a central vending machine administration unit, that in turn uses a 3G access system to call for maintenance or supplies. Minor problems can be relayed to the mall technician directly through his or her Bluetooth wireless communicator. Pricing changes can be sent from the central administration unit and locally broadcast to all Bluetooth vending machines.

Another application where Bluetooth wireless technology can complement 3G systems is electronic mail. When the reception is complete, the notebook can notify the user via a short message over the Bluetooth link to his mobile phone that he has e-mail, and if an item is urgent, this fact can be forwarded as well. The things you can do while in the office or stuck in traffic include: Interrogate the refrigerator for its contents, so needed items can be picked up on the way home. Set the house temperature to a personal preference before arriving home.

Despite getting home late, that favorite TV program is not missed; it is recorded by remotely activating the VCR. Chapter 1 Problems with Bluetooth The idea behind the Bluetooth specification is to replace the cables that tie devices to one another with a single short-range radio link.

It is expert ed that, within a few years, about 80 percent of mobile phones will carry a Bluetooth chip that can provide a wireless connection to similarly equipped notebook computers, printers and, potentially, any other digital device within about 30 feet As well as defining how these devices find and talk to each other, the Bluetooth specification also ties into existing data networks, including the Internet.

In the future, you might tap out an e-mail on your palmtop, tell it to make the Internet connection through your mobile phone, print a copy on the printer upstairs, and store the orig- inal on your desktop PC As promising as Bluetooth wireless technology is, it is severely limit- ed in terms of its data rate of about 1 Mbps. As noted, the Bluetooth specification can scale upward to support wireless data transmission applications operating in the 5-GHz range, supporting connections to devices up to feet away.

This type of technology evolution is not without precedent When the Infrared Data Association IRDA introduced its specification for Serial Infrared SIR data link technology in , it supported connec- tions between devices at only A year later, the IRDA extended the SIR to transfer information at 4 Mbps and within the next four years, it released its specification for infrared connectivity at 16 Mbps. There is no reason why the Bluetooth SIG cannot greatly extend the speed and range of its technology within a similar time- frame to encompass more applications.

If there is one problem with Bluetooth wireless technology, it is that it may have been over hyped. For example, Bluetooth devices were pro- moted well before the standards were ready for release. It was announced early to create momentum because the Bluetooth SIG want- ed many companies involved in developing products and applications Originally, the Bluetooth SIG had hoped that the technology would be built into hundreds of millions of devices before A report by US. That potential is still a way off. It will be at least another three years before Bluetooth chips will be cheap enough to be included in mainstream devices such as mobile The Case for Bluetooth 45 phones and handheld computers.

Despite the delay, the sheer weight of industry support for the Bluetooth specification— now com- panies — should eventually ensure that the standard will become com- monplace. Bluetooth wireless technology is not the first technology to appear late, nor will it be the last. Bluetooth Qualification Program The Bluetooth S1G has set up a qualification process to ensure that products comply with the Bluetooth specification. Upon passing of this qualification process, products can display the Bluetooth brand mark, signifying to consumers that they will interoperate as expected.

Any product that displays the Bluetooth brand mark must be licensed to use the mark and only products that pass the qualification test can be issued a license. Ah hardware or software modifications to a qualified product are documented and reviewed by the BQB that issued the qualifica- tion certificate for the product The qualification requirements are not the same for all products.

Those that arc specifically designed and marketed as development tools or demonstration kits are exempt from testing requirements, and qualification is possible for these products by filing a simple dec- laration of conformance Products that integrate a Bluetooth compo- nent that has been prequalified may be exempt from repeating tests for which the component is prequalified. Soon people all over the world will enjoy the convenience, speed, and security of instant wireless connec- tions.

To meet these expectations, Bluetooth components are likely to be embedded in hundreds of millions of mobile phones, PCs, lap- Chapter 1 tops, and a whole range of other electronic devices in the next few years. According to the research firm IDC, Bluetooth wireless technology will be embedded in more than million devices in the U. In addition, the tech- nology will move beyond the obvious devices such as laptops and handhelds to a variety of other devices such as printers, digital cam- eras, and other consumer devices.

IDC expects smart phones to be among the earliest adopters of the Bluetooth specification, with near- ly 6 percent of all digital phones including the technology by year- end Printers will begin integrating Bluetooth wireless technology in the to timeframe. Cahners In-Stat Group predicts Blue- tooth wireless technology will be a built-in feature in more than million products worldwide by Summary The Bluetooth specification can ease connection not only to the phone system or the Internet but also between devices. Indeed, the focus of Bluetooth wireless technology on low-cost, high levels of integration and ease of configuration has the potential to change cur- rent mobile computing and network connectivity paradigms.

More- over, because Bluetooth wireless technology supports both voice and data and a wide range of applications — from file synchronization and business card exchange to Internet access — it will strengthen the mobile computing offerings of all vendors. These include not only devices like notebook computers but also wireless connectivity solu- tions such as Wireless Domino Access and IBM Mobile Connect. Often, you will find that more than one of these technologies is required to meet your needs. Infrared and Bluetooth wireless technologies, for example, provide complementary implementations for data exchange and voice applications The capabilities of Bluetooth wireless devices complement infrared's point-and-shoot ease of use with omni- directional signaling, longer-distance communications, and capacity to The Case for Bluetooth TABLE 1.

For some devices, having both Bluetooth and infrared components will provide the optimal short-range wireless solution. For other devices, the choice of adding Bluetooth or infrared components will be based on the applications and intended usage models. The story on short-range wireless communications is still being written; both infrared and Bluetooth wireless technology will be major driving forces for development in this area.

The standard specifies how mobile phones, wireless information devices WIDs , handheld computers, and personal digital assistants PDAs using Bluetooth wireless components can interconnect with each other, with desktop computers, and with office or home phones. With its use of spread-spectrum technology, the first generation of the Bluetooth specification permits the secure exchange of data up to a rate of about 1 Mbps — even in areas with significant electromagnet- ic activity. With its use of continuously variable slope delta modula- tion CVSD for voice encoding, the Bluetooth specification allows speech to be carried over short distances with minimal disruption.

This chapter explores basic transmission concepts with the objective of establishing how the Bluetooth wireless specification operates to handle data and voice. In the process, the capabilities of Bluetooth wireless technology will become apparent and the foun- dation will be laid for the more detailed discussions of Bluetooth wireless technology in subsequent chapters.

Serial versus Parallel Like other communication technologies, Bluetooth wireless technolo- gy uses serial communication to transmit data in binary form Os and Is. A Bluetooth wireless device does this over a radio frequency RF link, but serial data communication is used over infrared as well as copper and fiber links.

Serial communication entails the transmission of data in sequential fashion, with the Is and Os following each other down the link to the remote device. This mode of information trans- fer applies to both asynchronous and synchronous data communica- tion. Parallel communication, on the other hand, conveys multiple bits at the same time, with each bit traveling over its assigned wire within a cable.

Most readers are famil- iar with the RS serial ports on their computers that are used for making the connection to an external modem at speeds up to 20 Kbps, or the newer high-speed USB Universal Serial Bus ports for making the connection to other peripherals, such as page scanners, at speeds of up to 12 Mbps.

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But serial transmission is not used just for connecting local devices to each other. If 8 bits are sent at a time, this will require 8 channels or wires, one for each data bit. To transfer data in this way, a separate channel or wire is used for the clock signal, which serves to inform the receiver when data are available. Another channel or wire would be used by the receiver to acknowledge receipt of the data, to indicate that it is ready to accept more data.

Parallel transmission mainly takes place within a computer or between a computer and a locally attached peripheral device such as a printer. Data going between a disk drive and a disk controller within your PC, for example, are transferred in parallel fashion through a ribbon cable. The most familiar application of parallel transmission is printing, in which a cable connects a computer's parallel port to a printers parallel port. The standard parallel port on a PC typically sends data at , bits per second. However, parallel transmission is good only for short distances, such as linking components within the computer, making a local connection from the computer to a printer or to some other device such as an external ZIP drive.

The serial and parallel data transmission methods are compared in Figure Comparison of parallel and serial transmission Parallel Serial s i E Bluetooth devices transmit data to other devices in serial fashion over wireless connections— synchronously or asynchronously, depending on the application. But internal processes in the Bluetooth devices themselves use a combination of parallel and serial transmis- sion. For example, to encrypt data for serial transmission over a wire less link, the Bluetooth device employs a stream ciphering process that loads four inputs in parallel to a payload key generator, which uses this information to formulate a payload key Figure 2.

The key stream generator sends the payload key in serial fashion to the encoder, where it is encrypted before being sent out over the wireless link, also in serial fashion. The sending and receiving devices use this key to establish mutual authentication so that subsequent message flow between them will be secure. Only with the proper key can the two stations unlock received data. When IBM built its PC, it opted to not use the conductor connector from the dominant print- er manufacturer of the time, which was Centronics Instead, IBM equipped its com- puters with the pin D shell connector-the DB connector.

Over the years, printer manufacturers have stuck with the Centronics connectors, while PC manufacturers have standardized on DB connectors This is the reason why special adapter cable is needed to make the connection between the two devices. Asynchronous versus Synchronous The problem with serial data transmission is how to synchronize the receiver with the sender so that the receiver can detect the beginning of each new character in the bit stream being presented to it. Without synchronization, the receiver will not be able to interpret the incom- ing bit stream correctly. There are two approaches to serial data trans- mission that solve the problem of synchronization: The Bluetooth specification supports both.

In asynchronous transmission, synchronization is established by bracketing each set of 8 bits by a start and stop bit. A start bit is sent by the sending device to inform the receiving device that a character is being sent. The character is then sent, followed by a stop bit, which indicates that the transfer of that character is complete.

Bluetooth Demystified

This process continues for the duration of the session. In synchronous transmission, data goes out over the link as a con- tinuous stream of bits. Start and stop bits are not used to bracket each character. Instead, the devices at each end of the link rely on timing as the means of determining where characters begin and end in the bit stream. For this method of transmission to work properly, however, the devices at each end of the link must be in perfect synchronization with each other using a common clock source.

They accomplish this 54 Chapter 2 by sending special characters, called synchronization, or syn, charac- ters before sending any user data. When the docks of each device are in synchronization, the user data are sent Asynchronous Asynchronous means that the bits in the serial data stream are not locked to a specific clock at the receiving end. This makes the asyn- chronous method of serial data transmission ideal for PC or simple terminal connections, where characters are generated at irregular intervals from a keyboard.

The advantage of asynchronous transmis- sion in this case is that each individual character is self-contained, so that if it becomes corrupted along the way, the characters before it and after it will be unaffected. Only the lost or corrupt character needs to be retransmitted In the PC environment, 7- or 8-bit characters are often used- Seven bits are enough to encode all upper- and lowercase characters, symbols and function keys, which number , in conformance with the American Standard Code for Information Interchange ASCII , An optional eighth bit, called the parity bit , is used to check data integrity.

When used, it is inserted between the last bit of a character and the first stop bit As will be discussed later, a stop bit is used in asynchro- nous communication to indicate the end of a sequence of bits form- ing a character Figure 2. Basic Concepts 55 The parity bit is included as a simple means of error checking. There is even and odd parity. The devices at each end of the connection must have the same parity setting.

The idea is that you specify ahead of time whether the parity of the transmission is to be even or odd. This is done from within Windows when configuring the connection prefer- ences the modem will use for dialup networking Figure Figure 2 A The connection preferences for a U. Suppose the parity chosen is odd. The transmitter will then set the parity bit in such a way as to make an odd number of Is among the data bits and the parity bit For example, if there are five Is among the data bits, already an odd number, the parity bit will be set to 0.

While this discussion of the parity bit applies to the modem con- nections most people are familiar with, it is also useful for under- standing how this type of bit is used in wireless data communications between Bluetooth devices to implement rudimentary error correc- tion. The data packets can be transferred with parity enabled or dis- abled. If it is enabled, users of Bluetooth devices will be able to config- ure their connection preferences for even or odd parity, depending on the host system they are connecting with.

When it comes to voice, however, even though Bluetooth devices package digitally encoded speech into packets, parity is not enabled. Chapter 2 With asynchronous communication, the transmitter and receiver only have to approximate the same clock rate. For a bit sequence, the last bit will be interpreted correctly even if the sender and receiver clocks differ by as much as 5 percent This makes asynchronous a relatively sim- ple and, therefore, inexpensive method of serial data transmission.

For example, to transmit 1, characters, or 8, bits, 2, extra bits must be transmitted for the start and stops, bringing the total number of bits sent to 10, The 2, extra bits is equivalent to sending more characters over the link. Bluetooth wireless technology supports one asynchronous channel that provides a data rate of almost 1 Mbps. The asynchronous connec- tionless link ACL supports data traffic on a best-effort basis. The ACL link supports packet-switched, point-to-multipoint connections, which typically are used for data. If errors are detected at the receiv- ing device, a notification is sent in the header of the return packet, so that only lost or corrupt packets need to be retransmitted.

The ACL link can operate in symmetrical or asymmetrical fashion. Symmetrical means that the link offers the same data rate in both the send and receive directions. Asymmetrical means that the link offers a different data rate in the send and receive directions. For symmetrical connections, the maximum data rate is Specifying the loca- tion of the Web page, on the other hand, requires far less bandwidth in the send direction.

There are Digital Subscriber Line DSL services, which operate over ordinary telephone lines, that are either asymmetrical or symmetrical. Asymmetrical Digital Subscriber Line ADSL runs at up to 8 Mbps in the downstream direction toward the user and up to Kbps in the upstream direction toward the Internet , with the actual speeds in each direction dependent upon the distance from the cus- tomer to the carrier's Central Office CO.

This type of link provides cir- cuit-switched, point-to-point connections, which typically are used for voice, data, and multimedia traffic using reserved bandwidth. SCO links are symmetrical, providing the same amount of bandwidth in both the send and receive directions. DATA In dispensing with the need for start-stop bits, synchronous transmis- sion relies on accurate timing between the sending and receiving devices to make sense of the Is and Os in the bit stream during decod- ing.

If both devices use the same clock source, then transmission can take place with assurance the bit stream will be accurately interpreted by the receiver. To guard against the loss of synchronization, the receiver is periodically brought into synchronization with the trans- mitter through the use of control bits embedded somewhere in the bit stream.

Bluetooth demystified /Nathan J. Muller. – National Library

In the synchronous method of transmission, data are not sent as individual bytes bracketed by start-stop bits, but as packets in reserved time slots that are set up between specific sending and receiving devices. Synchronous transmission is usually much more efficient in the use of bandwidth than asynchronous transmission, if only because the data field is usually much larger than the overhead fields. Another advantage of synchronous transmission is that the packet structure allows for easy handling of control information.

There is a natural position, usually at the start of the packet, or through the use of a setup message as in the case of the Bluetooth architecture, for any special codes needed for conveying timing parameters and speci- fying the reserved slots. VOICE The Bluetooth specification specifies three synchronous channels of 64 Kbps each, the same amount of bandwidth used to convey voice conversations over digital T-carrier lines or ISDN services over the Public Switched Telephone Network PSTN , Unlike the data setup, packets carrying voice can never be retransmitted because the result- ing delay would be disruptive to both speaker and listener.

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Briefly, PCM samples the changing amplitudes of the analog waveform 8, times a second and assigns each point along the sampled waveform a value that is expressed as an 8-hit word, or byte Figure 2. By sam- pling the analog waveform in this manner, a person's voice can be captured and represented in digital form. The resulting bit stream is sent down the link in the form of electrical pulses that represent Os and Is.

At the receiving device, this information is decoded to repre- sent a very close approximation of the original analog waveform, which results in speech intelligible to the listener. The resulting values are then encoded into 8-bit words. This results in a transmission rate of 64, bits per second, or 64 Kbps, which constitutes the size of a basic voice channel on a digital link, whether the link is a wired or wireless connection.

At the sending device, CVSD compares the input analog voltage with an internal reference voltage. When the reconstruction is plotted, the result is a continuously varying slope. The steeper the slope up or down the larger the output change between samples Fig- ure 2. The CVSD algorithm increases the size of the step taken between samples each time the change continues in the same direc- tion.

Any difference between the sampled input and output signal, called quantizing noise , is filtered out to ensure the highest-quality reception at each end of the conversation. The sampling technique used by CVSD modulation makes it insen- sitive to random bit errors, which are experienced by users as white background noise.

However, when a speech segment is rejected because it contains errors, measures are taken to fill in the lost speech segment. In the unlikely event that errors cannot be corrected, the seg- ment is ignored, in which case the user experiences clipped speech — the cutting off of syllables. Spread Spectrum The Bluetooth wireless technology uses a digital coding technique called spread spectrum, a method of wireless communications that takes a narrowband signal and spreads it over a broader portion of the available radio frequency band.

Among other advantages, the result- ing signal is highly resistant to interference and more secure against interception. The same technology is used in cordless phones and wireless local area networks LANs. In recent years, CDMA systems have gained widespread global acceptance by wireless operators. This technique differs from that used to transmit voice and data over Time Division Multiple Access TDMA networks, which assigns each user a time slot in a narrow band of spectrum.

While Bluetooth wireless technology makes use of spread-spectrum technology, it also uses a derivative of TDMA, called Time Division Duplexing TDD , to provision the time slots used for voice and data communication. S and music composer George Antheil. When transistors became really cheap, the idea was used in cellular phone technology to keep conversations private. By the time the Navy used the idea, the original patent had expired and Lamarr and Antheil never received any royalty payments for their idea.

Chapter 2 During World War II, Lamarr had become intrigued with radio- controlled missiles and the problem of how easy it was to jam the guidance signal. She realized that if the signal could be made to jump from one frequency to another very quickly — like changing stations on a radio — and both the sender and receiver changed in the same order at the same time, then the signal could never be blocked with- out knowing exactly how and when the frequency changed. Although the frequency-hopping idea could not be implemented due to technology limitations at that time, it eventually became the basis for cellular communication.

The coding operation increases the number of bits transmit- ted and expands the amount of bandwidth used. Using the same spreading code as the transmitter, the receiver correlates and collapses the spread signal back down to its original form. The result is a highly robust wireless data transmission technology that offers substantial performance advantages over conventional narrowband radio systems.

Increasing the frequency range allows more signal components to be transmitted, which results in a more accurate reconstruction of the original signal at the receiving device. Narrowband Waveform Noise Level Spread Waveform Frequency Basic Concepts 63 One of the advantages of spread spectrum is that the spread signal has a much lower power density. This low power density, spread over the expanded transmitter bandwidth, provides resistance to a variety of conditions that can plague narrowband radio systems, including: Interference— A condition in which a transmission is being dis- rupted by external sources, such as the noise emitted by various electromechanical devices, or internal sources such as cross talk Jamming — A condition in which a stronger signal overwhelms a weaker signal, causing a disruption to data communications Multipath — A condition in which the original signal is distorted after being reflected off a solid object Interception — A condition in which unauthorized users capture signals in an attempt to determine their content.

Conventional narrowband radio systems transmit and receive on a specific frequency that is just wide enough to pass the information, whether voice or data. In assigning users different channel frequen- cies, confining the signals to specified bandwidth limits, and restrict- ing the power that can be used to modulate the signals, undesirable cross talk — interference between different users— can be avoided. These rules, enforced by regulatory agencies in each country, arc nec- essary because any increase in the modulation rate widens the radio signal bandwidth, which increases the chance for cross talk.

The main advantage of spread spectrum radio waves is that the sig- nals can be manipulated to propagate fairly well through the air, despite electromagnetic interference, virtually eliminating cross talk. This results in a more robust signal that is less susceptible to interference from similar radio-based systems, since they too are spreading their signals, but with different spreading algorithms.

Reinventing Hollywood David Bordwell. The Filter Bubble Eli Pariser. Communicating and Mobile Systems Robin Milner. Down and Dirty Pictures Peter Biskind. Teaching and Digital Technologies Geoff Romeo. Bluetooth Low Energy Robin Heydon. Technomobility in China Cara Wallis. The Audible Past Jonathan Sterne. Exposing the Magic of Design Jon Kolko. Other books in this series. Italian Demystified, Premium Marcel Danesi. Latin Demystified Richard Prior. Chinese Demystified Claudia Ross. English Grammar Demystified Phyllis Dutwin. Quality Management Demystified Sid Kemp. Minitab Demystified Andrew Sleeper.

Relativity Demystified David McMahon. Back cover copy Understand the Bluetooth standard.

Bluetooth telescope control Android & Windows

Compare its strengths and weaknesses against other technologies. Preview coming products and applications. See the protocols and usage models at work. This user-friendly guide provides a basic introduction and overview, then helps you find your way through the various applications and network configurations of the new Bluetooth wireless technology. Along the way, you'll get a revealing peek at how this promising technology will improve productivity and add new levels of convenience and flexibility to our lives.

Already chosen by more than companies seeking wireless solutions that seamlessly integrate PDAs, mobile phones, desktop computers, and LANs-- voice, e-mail, Internet, and data--Bluetooth is long on complexity. That's why you need this introduction to the new wireless standard from Nathan J. Muller--a technology expert who makes the Bluetooth standard understandable. Meticulously organized and highly readable, Bluetooth Demystified delves into every major aspect of the standard with contents that include: