What is Bluetooth?

Bluetooth is an industrial specification for wireless personal area networks (PANs). 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.

The name Bluetooth was born from the 10th century king of Denmark, King Harold Bluetooth who engaged in diplomacy which led warring parties to negotiate with each other. The inventors of the Bluetooth technology thought this a fitting name for their technology which allowed different devices to talk to each other

Introduction

Bluetooth is a radio standard primarily designed for low power consumption, with a short range (power class dependent: 10 centimeters, 10 meters, 100 meters) and with a low-cost transceiver microchip in each device.

Bluetooth lets these devices talk to each other when they come in range, even if they are not in the same room, as long as they are within up to 100 meters of each other, dependent on the power class of the product. Products are available in one of three power classes:

Bluetooth applications

• Wireless networking between desktops and laptops, or desktops in a confined space and where little bandwidth is required


• Bluetooth peripherals such as printers, mice and keyboards


• Bluetooth cell phones have been sold in large numbers, and are able to connect to computers, personal digital assistants (PDAs), certain automobile handsfree systems and various other devices. The standard also includes support for more powerful, longer-range devices suitable for constructing wireless LANs.


• Transfer of files (images, mp3s, etc) between mobile phones, Personal digital assistants (PDAs) and computers via OBEX


• Certain mp3 players and digital cameras to transfer files to and from computers


• Bluetooth headsets for mobile phones and smartphones


• Some testing equipment is bluetooth enabled


• Medical applications — Advanced Medical Electronics Corporation is working on several devices


• Certain GPS receivers transfer NMEA data via Bluetooth


• Bluetooth car kits — Acura, with the 2004 Acura TL, was the first motor vehicle manufacturer to install handsfree Bluetooth technology. Later, BMW added it as an option on its 3 Series, 5 Series, 7 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. Companies like Parrot or Motorola manufacture Bluetooth hands-free car kits for well-known brand car manufacturers.


• Certain data logging equipment transmits data to a computer via Bluetooth.


• For remote controls where infrared was traditionally used.


• Hearing aids — Starkey Laboratories have created a device to plug into some hearing aids [2]


• Sony's Playstation 3 will use Bluetooth technology for its wireless controllers. Also Hip Gear has already released a Bluetooth controller for the Xbox.


• Newer model Zoll Defibrilators for the purpose of transmitting Defibrilation Data and Patient Monitoring/ECG data between the unit and a reporting PC using Zoll Rescue Net software.

Specifications and Features

The Bluetooth specification was first developed by Ericsson, and was 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. Bluetooth is also known as IEEE 802.15.1.

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.


• added support for non-encrypted channels.


• Received Signal Strength Indicator (RSSI)

Bluetooth 1.2

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

• Adaptive Frequency-hopping spread spectrum (AFH), which improves resistance to radio frequency 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.


• 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. The main enhancement is the introduction of Enhanced Data Rate (EDR) of 2.1 Mbit/s. This has the following effects (Bluetooth SIG, 2004):

• 3 times faster transmission speed (up to 10 times in certain cases).


• Lower power consumption through reduced duty cycle.


• Simplification of multi-link scenarios due to more available bandwidth.


• Further improved BER (Bit error rate) performance.

The Future of Bluetooth

Rumors of the next step in bluetooth technology are floating in the air. This next-gen bluetooth technology allows even faster transfer speeds and a much improved range. The increased bandwidth and improved data rate may threaten to make WiFi technology obsolete, although some would argue that the opposite could be true as WiFi chips become cheaper and power consumption is reduced.

However, since both technologies are constantly increasing in penetration, it is very hard to predict what will happen. Since bluetooth penetration is largely driven by phone headsets and WiFi penetration almost purely driven by Internet access, it's quite possible that they continue to coexist for different purposes.

Communication & Connection

A Bluetooth device playing the role of the "master" can communicate with up to 7 devices playing the role of the "slave". This network of "group of up to 8 devices" (1 master + 7 slaves) is called a piconet.

At any given time, data can be transferred between the master and 1 slave; but the master switches rapidly from slave to slave in a round-robin fashion. (Simultaneous transmission from the master to multiple slaves is possible, but not used much in practice). Either device may switch the master/slave role at any time.

Bluetooth specification allows connecting 2 or more piconets together to form a scatternet, with some devices acting as a bridge by simultaneously playing the master role in one piconet and the slave role in another piconet. These devices have yet to come, though are supposed to appear next year (2007).

Origin of the name and the logo

The system is named after a Danish king Harald Blåtand (Harold I of Denmark in English), King of Denmark and Norway from 935 and 936 respectively, to 940 known for his unification of previously warring tribes from Denmark (including Skåne, present-day Sweden, where the Bluetooth technology was invented) and Norway. Bluetooth likewise was intended to unify different technologies like computers and mobile phones. The Bluetooth logo merges the Nordic runes analogous to the modern Latin H and B: ᚼ and ᛒ. 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.

This logo is also a variation on an older logo for Beauknit Textiles, a division of Beauknit Corporation. That logo, using the obvious connection of a reversed K and B for Beauknit, is wider and has rounded corners, but is otherwise the same.

The name was originally only a code-name for the project, but ended up sticking.