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Bluetooth Bites Information Retrieval

Maryellen Mott Allen

ONLINE, May 2001
Copyright © 2001 Information Today, Inc.


Internet world is replete with buzzwords, trends, and rumors about the latest technologies coming to the fore. Ask anyone these days what the new darling of the Internet is, and they will tell you without a doubt that it's wireless technologies. Online journals, newsgroups, discussion forums, and print publications concerning the Internet are engaged in a furious exchange of opinions in which the pros and cons of various wireless data transmission protocols are alternately praised and reviled. One such protocol, simultaneously adored and despised, is Bluetooth (http://www.bluetooth.com).

According to Cahners In-Stat Group (http://www.instat.com) in its July 2000 report, "Bluetooth 2000: To Enable the Star Trek Generation," the manufacture of Bluetooth-enabled equipment will exceed one billion units by 2005, and the market will be worth some $5 billion. Frost & Sullivan (http://www.frost.com) is equally optimistic. It forecasts global shipments of Bluetooth-enabled products to reach over 11 million units in 2001 and predicts $2.5 billion in revenues.

The name itself is enough to start you wondering. When discussing the dry topic of data transmission protocols, we are used to throwing around terms such as TCP/IP, RIP, or PPP. Whether or not we can decipher the acronym, the terms have been used so often that most people have some idea of what we are talking about. But mention Bluetooth to the uninitiated and you're likely to be met with puzzled looks.


Bluetooth, named after the 10th century Viking king Harald Bluetooth, is a de facto data transmission standard developed by Ericsson and backed by a host of other technology companies that make up the Bluetooth Special Interest Group (including Ericsson, Intel, Puma Technology, Microsoft, Motorola, Nokia, 3Com, Lucent Technologies, and Toshiba). Bluetooth employs the unlicensed radio frequency (RF) portion of the electromagnetic spectrum in the 2.4-2.4835 gHz range. More simply, Bluetooth is a low-power, spread-spectrum technology that uses frequency-hopping to ensure speedy, short-range wireless data transfer of up to 720 kbps at a range of 30-100 feet. Intended as a replacement for the short-range data cable, Bluetooth's original conception was as a wireless peripheral interface, linking print- ers, monitors, keyboards, and other peripheral devices to the CPU. However, the potential for the technology is much greater, offering the ability to link devices of different types, forming instant workgroups across multiple platforms in a seamless fashion. So how does Bluetooth work?

The Bluetooth standard is a complex conglomeration of protocols arranged in a protocol stack, which, when diagramed, somewhat resembles a Dagwood-style sandwich. To put it more simply, Bluetooth relies upon radio frequencies to transmit data, providing a universal bridge between devices on a network, or between devices from the outside and an existing network using a combination of circuit and packet-switching technologies. Bridges have the ability to link together different types of networks because a bridge delivers data based upon the MAC (Medium Access Control) address that is hard-coded into the network hardware by the factory that manufactures it, and it is unique for every device. This differs from other network devices, such as routers, that deliver network data based upon routable protocols such as TCP/IP. Because bridges operate at a lower level of the protocol stack, standards like Bluetooth can link unlike devices within a local network. The data is, like all network traffic, divided into packets. However, because Bluetooth is designed to work in the RF environment–a very noisy portion of the electromagnetic spectrum–it employs the use of shorter packets for transmission, and combines this with fast frequency-hopping to ensure a fairly robust connection.

When a message is sent over a Bluetooth connection, each packet is transmitted on a different frequency within a range of 2.4-2.4835 gHz. After the first packet is transmitted, the Bluetooth controller hops to a different frequency before sending out the next packet. The determination of which frequency within the given range will be used to start packet transmission is semi-random and is controlled by the Bluetooth Radio portion of the protocol stack. This frequency remains fixed for the duration of each packet. However, once the initial transmission frequency is chosen for the first packet, the remaining frequencies are cycled through for each subsequent packet in a determined fashion. This is known as the phase.


When two or more Bluetooth-enabled devices are within range of each other, they automatically start communicating. Each Bluetooth-enabled device periodically broadcasts an inquiry message to see if there are any other Bluetooth devices in the area. If there is a response from another device, the originator of the inquiry message becomes the Master unit and the responder becomes the Slave. This arrangement is completely dependent upon which device is the first to send the inquiry message out when it comes within range, and does not resemble a client/server relationship. After this initial contact, the Master sends the slave(s) information about how they will communicate (i.e. the initial frequency and phase). These ad hoc networks are called Piconets. Collections of Piconets form Scatternets. Bluetooth supports point-to-point as well as point-to-multipoint links depending upon the number of devices within communication range. In each case, the connections are peer-to-peer.

Bluetooth can send data along four different channels simultaneously. Included is an asynchronous data channel (meaning packets are not sent out in pre-selected timeslots governed by the processor clock, but rather whenever there's an opportunity), and up to three simultaneous synchronous voice channels, or a combination channel, simultaneously supporting asynchronous data and synchronous voice. Each synchronous voice channel can support transfer rates of 64 kbps, and the asynchronous channel can support a bi-directional (two-way) asymmetric link of up to 721 kbps in either direction while permitting 57.6 kbps in the return direction.

So what does all of this have to do with libraries and information professionals? A lot, if the push to promote the standard is successful.


Imagine an environment where users enter the library with their personal digital assistants (PDAs) and are instantly connected to the network. They can pull up their records, search proprietary databases and the Web, check email, download information, and even check out materials from the stacks without ever having to stop at the checkout desk. All of these things are theoretically possible using the Bluetooth standard. Bluetooth-enabled networks have the potential to allow libraries to offer the kind of value-added services often held up as the holy grail of mission statements.

In Ken Varnum's insightful article entitled "Information at Your Fingertips: Porting Library Services to the PDA," appearing in the September/ October 2000 issue of ONLINE, he illustrates how Ford Motor Company's corporate library is taking the initiative in porting library services to handheld devices, such as the PDA. The article demonstrates precisely how the engaged and aware information professional is finding new avenues for reaching out to users. Varnum explains how the library has effectively employed a third-party software package to translate Web pages into PDA-friendly files that users can download and take along with them on trips away from the office. This technology allows users to view documents, check and respond to email messages, and even fill out online forms. The drawback, of course, is that the user must return to the office and interface the PDA with a PC in order to synchronize the devices and actually transmit the email, form, etc. The PDA itself is not connected online and does not allow for real-time operation.

Now, take that scenario and replace the old PDA with a new Bluetooth-enabled PDA. Then suppose traveling users find themselves at a hotel, airport, or library with a Bluetooth-enabled network connected to the Internet. Our users can now not only respond to email messages, but send them as well. They can conduct research and download updated documents. They can even use their PDAs to make phone calls. In short, the user has been given the type of information access that would have been unimaginable just a few years ago.


Even the more traditional academic or public libraries could reap the benefits of a Bluetooth-enabled network. Librarians at the reference desk assisting patrons in their research could directly beam the results to the patron's PDA, avoiding the cost of printing out the documents. Patrons with Bluetooth enabled devices connected to the library network could work together in ad hoc user groups, sharing information electronically. Library instructional sessions could be greatly facilitated by turning a patron's personal device into an instant workstation, eliminating the need for the library to purchase and maintain expensive computer labs. Network printers could be placed throughout the library for those who wish to obtain printouts without the restrictions that come with traditional network cables or the line-of-sight problems that accompany devices using infrared. A prototype description of Swedish rail traffic in the future (http://www.swedetrack.se/usblue2.htm) proposes placing Bluetooth units at public libraries close to train stations to be used as passenger interfaces.

LEXIS-NEXIS has teamed up with a primary developer of the Bluetooth Standard and member of the Bluetooth SIG, Red-M, a subsidiary of the Dutch company Madge Networks, to launch m-news. With content from LEXIS-NEXIS, m-news will provide subscribers with email updates and hypertext links to stories located on the Red-M Web site that detail Bluetooth industry developments. Registration is required but the service is free (http://www.redm.com/aboutred/newsroom/content.asp?Article=21).

And if all of that sounds too good to be true, you may be right.


The potential for Bluetooth is enormous, but its road to acceptance has been rife with criticisms and obstacles, some of which are substantial indeed. First there is the issue of cost. The original model developed by the Bluetooth SIG in 1998 called for a figure of $5 to integrate Bluetooth radio transceivers and link-level controllers into hand-held devices. The reality has been more in the range of $50 for the components, or slightly less if purchased in large quantities. And this is the price paid by the original equipment manufacturers (OEMs). Undoubtedly, by the time the device reaches the market, the price will be considerably higher. This has effectively put it out of the reach of most consumers. The inflated prices, however, are not the result of corporate greed, but more the unpredictable consequence of the technical difficulty of producing the chips and the resulting size of the chip being somewhat larger than anticipated.

Another significant problem is that of interference. As Joe Wilcox, staff writer for CNET News.com notes in his September 15 article, "As Bluetooth Nibbles, Competition Lurks" (http://news.cnet.com/news/0-1003-200-2784702.html), the issue of frequency interference could potentially harm Bluetooth a great deal. Because Bluetooth uses the unlicensed radio portion of the electromagnetic spectrum, transmissions in that band must compete with industrial microwave ovens, stadium lights, garage door openers, cordless telephones, and virtually any wireless household appliance, even baby monitors. More detrimental to the long-term health of the Bluetooth standard, however, is its interference with two other wireless standards using the same 2.4 gHz band that are older and more established: that of the 802.11B and the HomeRF. While these standards lack the catchy name and media hype that Bluetooth currently enjoys, 802.11B allows portable electronic devices to connect to an existing network at distances up to 300 feet rather than the paltry 100 feet that limits Bluetooth. Additionally, HomeRF recently won a ruling from the FCC that allows it to expand its bandwidth to 5mHz (up from 1mHz), effectively increasing transmission speeds to 10 Mbps. While there is room for these standards to operate in a complementary fashion within a wireless network environment, another challenge rears its head: compatibility.

The bickering over who has control over various portions of the spectrum gets even uglier when dealing with the unlicensed portion that Bluetooth and other standards exploit. There is little that the FCC can do to regulate this area and still preserve the integrity of maintaining an open portion of bandwidth. To get around some of the interference problems, both HomeRF and Bluetooth use frequency-hopping. In contrast, the 802.11B standard has developed around a direct-sequence model in which only one frequency is used for transmission. The use of these two different methods introduces incompatibility between devices. A frequency-hopping Bluetooth device and a direct-sequence 802.11B device would not be able to communicate with each other.

Add to that the security problems inherent in the Bluetooth standard, and the outlook appears grim. There is a security layer within the specification for Bluetooth, but by all accounts, it is easily misunderstood and prone to confusion. As Wilcox reports, an analyst with Gartner, a leading Internet industry consulting firm states, "Bluetooth is a disaster waiting to happenÉthe specs cover (security), but unless you know what you're doing, it's possible to implement the spec in such a fashion (that) you aren't doing anything worthwhile."


The rollout of Bluetooth-enabled devices has experienced many delays as a result of some of these issues. When the Bluetooth SIG was first formed, the company fully expected to see widespread implementation by Christmas of 2000. Unfortunately, it has been only recently that Bluetooth-equipped devices have begun to trickle out of the development labs and into the hands of consumers. Even so, there are not enough Bluetooth products around to make it a worthwhile investment. One Bluetooth device is no good–you really need at least two to play. Yet it is important to bear in mind that these problems are not insurmountable. Dozens of companies have significant resources sunk into the development of Bluetooth. To abandon it would represent a tremendous loss of time and money. While the future of the technology is by no means secure (there are a lot of kinks to work out), you can rest assured that much effort will go into its continued development and promotion. We'll see within the next few years if Bluetooth will sink its teeth into the information industry, or bite itself in the butt.

Harald Bluetooth

Harald Bluetooth, son of Denmark's first king, Gorm the Old, from whom the present Danish queen, Margarethe II, traces direct descent, did not have blue teeth. Instead, the name refers to a great man with a dark complexion. The Danish word for blue, blå, also meant dark and the words for man, mand, and tooth, tand, sound much the same. Harald Bluetooth is credited with Christianizing Denmark, Norway, and parts of Sweden and with uniting the countries into one kingdom. At the time of his rule, somewhere between 940 and 980 AD, southern Sweden was part of Denmark. In southern Sweden is the city of Lund, which is where Ericsson developed the Bluetooth technology. According to Ericsson in its discussion of Harald Bluetooth (http://bluetooth.ericsson.se/bluetoothf/beginnersg/default.asp?page=2), "One of his skills was to make people talk to each other....," hence the choice of Bluetooth to name this communications standard. If you're ever in Jelling, Denmark, you can view the rune stone Harald Bluetooth raised in honor of his parents. There's another, vastly newer, rune stone dedicated to Bluetooth himself. It's outside Ericsson's Mobile Communications office in Lund.

Maryellen Mott Allen (mallen@lib.usf.edu) is Instructor Librarian, University of South Florida Tampa Campus Library.

Comments? Email letters to the Editor at marydee@infotoday.com.

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Copyright © 2001, Information Today, Inc. All rights reserved.