This article is about the Bluetooth wireless specification. For King Harold Bluetooth, see Harold I of Denmark

Bluetooth is an industrial specification for wireless personal area networks (PANs) first developed by Ericsson, later formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1999. It was established by Sony Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies as Associate or Adopter members.

Contents

1 Introduction 2 General Information 2.1 Embedded Bluetooth 3 Features by Version 3.1 Bluetooth 1.0 and 1.0B 3.2 Bluetooth 1.1 3.3 Bluetooth 1.2 3.4 Bluetooth 2.0 4 Future Bluetooth Uses 5 Security concerns 6 Bluetooth profiles 7 See also 8 External links

Introduction

The system is named after a Danish king Harald Blåtand (Harold Bluetooth in English), King of Denmark and Norway from 935 and 936 respectively, to 940 known for his unification of previously warring tribes from Denmark, Norway and Sweden. Bluetooth likewise was intended to unify different technologies like computers and mobile phones. The Bluetooth logo merges the Nordic runes for H and B. This is the official story: however, the actual Harald Blåtand that was referred to in naming Bluetooth was most probably the liberal interpretation given to him in The Long Ships by Frans Gunnar Bengtsson, a Swedish best-selling Viking-inspired novel.

Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, low-cost, globally available short range radio frequency.

Bluetooth lets these devices talk to each other when they come in range, even if they're not in the same room, as long as they are within 10 metres (32 feet of each other).

General Information

The latest version shipping currently to consumers as embedded Bluetooth and USB dongles is 1.2, while version 2.0 core chips are available to OEMs (as of November 2004).

It is a wireless radio standard primarily designed for low power consumption, with a short range (from 10 up to 100 meters) and with a low-cost transceiver microchip in each device.

It can be used to wirelessly connect peripherals like printers or keyboards to computers, or to have PDAs communicate with other nearby PDAs or computers.

Cell phones with integrated Bluetooth technology have also been sold in large numbers, and are able to connect to computers, PDAs and, specifically, to handsfree devices. BMW was the first motor vehicle manufacturer to install handsfree Bluetooth technology in its cars, adding it as an option on its 3 Series, 5 Series and X5 vehicles. Since then, other manufacturers have followed suit, with many vehicles, including the 2004 Toyota Prius and the 2004 Lexus LS 430. The Bluetooth car kits allow users with Bluetooth-equipped cell phones to make use of some of the phone's features, such as making calls, while the phone itself can be left in a suitcase or in the boot/trunk, for instance.

However, the standard also includes support for more powerful longer-range devices suitable for constructing a wireless LAN. Every Bluetooth device can simultaneously maintain up to 7 connections, but only one active connection at the time. These groups (maximum of 8 devices: 1 host and 7 slaves) are called piconets. The Bluetooth specification also enables the possibility to connect two piconetworks together, with one master device acting as a bridge. These devices have yet to come, though are supposed to appear within the next two years. Every device can be configured to constantly announce its presence to nearby devices in order to establish a connection. It is also possible to password protect a connection between two devices so that no one can listen in.

The protocol operates in the license-free ISM band at 2.45 GHz. In order to avoid interfering with other protocols which use the 2.45 GHz band, the Bluetooth protocol divides the band into 79 channels and changes channels up to 1600 times per second. Implementations with versions 1.1 and 1.2 reach speeds of 723.1 kbit/s. Version 2.0 implementations feature Bluetooth Enhanced Data Rate (EDR), and thus reach 2.1 Mbit/s. Technically version 2.0 devices have a higher power consumption, but the three times faster rate reduces the transmission times, effectively reducing consumption to half that of 1.x devices (assuming equal traffic load).

Bluetooth should not be compared to Wi-Fi, which is a faster protocol requiring more expensive hardware that covers greater distances and uses the same frequency range . While Bluetooth is a cable replacement creating personal area networking between different devices, Wi-Fi is a cable replacement for local area network access. A glib summary is that Bluetooth is wireless USB whereas Wi-Fi is wireless Ethernet.

Many USB Bluetooth adapters are available, some of which also include an IrDA adapter.

Embedded Bluetooth

Bluetooth devices and modules are increasingly being made available which come with an embedded stack and a standard UART port. The UART protocol can be as simple as the industry standard AT protocol, which allows the device to be configured to cable replacement mode. This means it now only takes a matter of hours (instead of weeks) to enable legacy wireless products that communicate via UART port.

Features by Version

Bluetooth 1.0 and 1.0B

Versions 1.0 and 1.0B had numerous problems and the various manufacturers had great difficulties in making their products interoperable. 1.0 and 1.0B also had mandatory Bluetooth Hardware Device Address (BD_ADDR) transmission in the handshaking process, rendering anonymity impossible at a protocol level, which was a major set-back for services planned to be used in Bluetooth environments, such as Consumerium.

Bluetooth 1.1

In version 1.1 many errata found in the 1.0B specifications were fixed. There was added support for non-encrypted channels.

Bluetooth 1.2

This version is backwards compatible with 1.1 and the major enhancements include

• Adaptive Frequency Hopping (AFH), which improves resistance to radio interference by avoiding using crowded frequencies in the hopping sequence
• Higher transmission speeds in practice
• extended Synchronous Connections (eSCO), which improves voice quality of audio links by allowing retransmissions of corrupted packets.
• Received Signal Strength Indicator (RSSI)
• Host Controller Interface (HCI) support for 3-wire UART
• HCI access to timing information for Bluetooth applications.

Bluetooth 2.0

This version is backwards compatible with 1.x and the major enhancements include

• Non-hopping narrowband channel(s) introduced. These are faster but have been criticised as defeating a built-in security mechanism of earlier versions; however frequency hopping is hardly a reliable security mechanism by today's standards. Rather, Bluetooth security is based mostly on cryptography.
• Broadcast/multicast support. Non-hopping channels are used for advertising Bluetooth service profiles offered by various devices to high volumes of Bluetooth devices simultaneously, since there is no need to perform handshaking with every device. (In previous versions the handshaking process takes a bit over one second.)
• Enhanced Data Rate (EDR) of 2.1 Mbit/s.
• Built-in quality of service.
• Distributed media-access control protocols.
• Faster response times.
• Halved power consumption due to shorter duty cycles.

Future Bluetooth Uses

One of the ways Bluetooth technology may become useful is in Voice over IP. When VOIP becomes more widespread, companies may find it necessary to employ telephones physically similar to today's analogue telephone hardware. Bluetooth may then end up being used for communication between a cordless phone and a computer listening for VOIP and with an infrared PCI card acting as a base for the cordless phone. The cordless phone would then just require a cradle for charging. Bluetooth would naturally be used here to allow the cordless phone to remain operational for a reasonably long period.

Security concerns

In November 2003, Ben and Adam Laurie from A.L. Digital Ltd. http://www.thebunker.net/index.html discovered that serious flaws in Bluetooth security lead to disclosure of personal data (see http://bluestumbler.org http://bluestumbler.org ). It should be noted however that the reported security problems concerned some poor implementations of Bluetooth, rather than the protocol itself.

In a subsequent experiment, Martin Herfurt from the trifinite.group http://trifinite.org/trifinite_group.html was able to do a field-trial at the CeBIT fairgrounds showing the importance of the problem to the world. A new attack called BlueBug http://trifinite.org/trifinite_stuff_bluebug.html was used for this experiment.

In April 2004, security consultants @Stake http://www.atstake.com revealed a security flaw that makes it possible to crack into conversations on Bluetooth based wireless headsets by reverse engineering the PIN.

This is one of a number of concerns that have been raised over the security of Bluetooth communications. In 2004 the first purported virus using Bluetooth to spread itself among mobile phones appeared http://www.theregister.co.uk/2004/06/15/symbian_virus/ for the Symbian OS. The virus was first described by Kaspersky Labs and requires users to confirm the installation of unknown software before it can propagate. The virus was written as a proof-of-concept by a group of virus writers known as 29a and sent to anti-virus groups. Because of this, it should not be regarded as a security failure of either Bluetooth or the Symbian OS. It has not propagated 'in the wild'.

In August 2004, a world-record-setting experiment http://trifinite.org/trifinite_stuff_lds.html (see also Bluetooth sniping) showed that with directional antennas the range of class 2 Bluetooth radios could be extended to one mile. This enables attackers to access vulnerable Bluetooth-devices from a distance beyond expectation.

Bluetooth uses the SAFER+ algorithm for authentication and key generation.

Bluetooth profiles

In order to use Bluetooth, a device must be able to interpret certain Bluetooth profiles. These define the possible applications. Following profiles are defined:

• Generic Access Profile (GAP)
• Service Discovery Application Profile (SDAP)
• Cordless Telephony Profile (CTP)
• Intercom Profile (IP)
• Serial Port Profile (SPP)
• Headset Profile (HSP)
• Dial-up Networking Profile (DUNP)
• Fax Profile
• LAN Access Profile (LAP)
• Generic Object Exchange Profile (GOEP)
• Object Push Profile (OPP)
• File Transfer Profile (FTP)
• Synchronisation Profile (SP)

This profile allows synchronisation of Personal Information Manager (PIM) items. As this profile originated as part of the infrared specifications but has been adopted by the Bluetooth SIG to form part of the main Bluetooth specification, it is also commonly referred to as IrMC Synchronization.

• Hands-Free Profile (HFP)
• Human Interface Device Profile (HID)
• Hard Copy Replacement Profile (HCRP)
• Basic Imaging Profile (BIP)
• Personal Area Networking Profile (PAN)
• Basic Printing Profile (BPP)
• Advanced Audio Distribution Profile (A2DP)
• Audio Video Remote Control Profile (AVRCP)
• SIM Access Profile (SAP)

Compatibility of products with profiles can be verified on the Bluetooth Qualification website http://qualweb.bluetooth.org/Template2.cfm?LinkQualified=QualifiedProducts .

See also

• Bluechat
• Bluejacking - a form of communication via Bluetooth
• Bluetooth sniping
• Blunt - Bluetooth protocol stack for Newton OS 2.1
• Cable spaghetti - a problem wireless technology hopes to solve
• IrDA
• Jini
• LibertyLink
• OSGi Alliance
• Salutation
• Service Location Protocol
• Toothing
• UPnP
• Wi-Fi
• Wireless dating
• Wireless AV kit with Bluetooth for modern LCD TV and computer displays.
• ZigBee - an alternative digital radio technology

External links

• Bluetooth SIG public pages http://www.bluetooth.com/
• Bluetooth Membership site http://www.bluetooth.org/
• Howstuffworks.com explanation of bluetooth http://www.howstuffworks.com/bluetooth.htm
• The Bluetooth Car Concept http://develop.consumerium.org/wiki/index.php/User:Juxho/Bluetooth_Car
• A series of guides http://www.geekzone.co.nz/content.asp?contentid=449 on how-to connect devices like mobile phones, PDAs, desktop/laptops, headsets and use different Bluetooth services
• Mapping Salutation Architecture APIs to Bluetooth Service Discovery Layer http://citeseer.nj.nec.com/context/1174778/0
• Bluetooth™ Security White Paper http://www.bluetooth.com/upload/24Security_Paper.PDF
• Security Concerns http://www.atstake.com/research/reports/acrobat/atstake_war_nibbling.pdf
• Laptops, PDA and mobile (cell) phones with Bluetooth(TM) and Linux http://tuxmobil.org/bluetooth_linux.html
• Bluetooth qualified products http://qualweb.bluetooth.org/Template2.cfm?LinkQualified=QualifiedProducts
• Bluecarkit discussion forum about Bluetooth car handsfree http://www.bluecarkit.com/forum
• Radio-Electronics.Com - Overview of Bluetooth and its operation http://www.radio-electronics.com/info/wireless/bluetooth/bluetooth_overview.php