Bluetooth

By: Nick Greaner

What is Bluetooth?

• Bluetooth is an open wireless protocol for exchanging data over short distances (using short radio waves) from fixed and mobile devices, creating personal area networks (PANs). It was originally conceived as a wireless alternative to certain types of data cables, like the RS-232 data cable. It can connect several devices, overcoming problems of synchronization.

Bluetooth History:

• 1998: The Bluetooth Special Interest Group (SIG) is formed with five companies.

• The name Bluetooth is officially adopted.• 1999: The Bluetooth 1.0 Specification is released.• 2000: First Bluetooth mobile phone.• First Bluetooth PC Card.• First chip to integrate radio frequency, baseband,

microprocessor functions and Bluetooth wireless software.

• First Bluetooth headset.

Bluetooth History, Cont.

• 2001: First Bluetooth printer.

• First Bluetooth laptop.

• The Bluetooth SIG, Inc. is formed as a privately-held trade association.

• 2002: First GPS receiver.

• Bluetooth wireless qualified products now number 500.

• 2003: First MP3 player.

• First FDA-approved medical system.

• 2004: First Bluetooth stereo headphones.

Bluetooth History, Cont. Cont.

• 2005: First Bluetooth Sunglasses.• 2006: First Bluetooth watch.• First Bluetooth picture frame.• Bluetooth wireless reaches an installed base of 1 billion

devices.• First Bluetooth alarm-clock radio.• 2007: First television with Bluetooth capabilities.• 2009: The Bluetooth SIG adopts Core Specification

Version 3.0 + HS making Bluetooth high speed technology a reality.

How Bluetooth Works:• Bluetooth transmits information through low-power radio

waves. It communicates on a frequency of about 2.45 gigahertz. This frequency band has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM).

• http://electronics.howstuffworks.com/bluetooth2.htm

How Bluetooth Works, Cont.

• Bluetooth sends out very weak signals that are about 1 milliwatt in power. Cell phones can transmit up to 3 watts. Bluetooth devices only have a range of around 32 feet due to their low power. This cuts the chances of interference with your other Bluetooth devices, such as your computer or television. Bluetooth doesn’t need a clear line of sight to communicate with other devices, despite its low power.

The Bluetooth signals won’t be blocked by the walls in your house, making it the ideal choice for communication

between devices around your house.

How Bluetooth Works, Cont. Cont.

• Ex: You have a Bluetooth-enabled cell phone, and you’re not at home. You’re talking with a friend on the phone and tell them to call you back later. You go home. As soon as you get home, your cell phone sends a signal to your computer, telling it that you are no longer out and about, but are now at home. Your friend calls you back. The call is re-routed to your home phone, even though your friend called your cell phone’s number. Fancehhh!

How Bluetooth Works, Cont. Cont. Cont.

• Bluetooth systems create a personal-area network (PAN), or piconet. This piconet could have an area the size of a

house or one as small as from your phone to your headset. Once this piconet is created, all of the devices will hop

from frequency to frequency rapidly, in unison, to avoid other piconets that may be operating in the same room.

                                                                                                                                                

How Bluetooth Works: Frequency Hopping

• The logical link control and adaptation protocol (L2CAP) is the protocol in each Bluetooth device’s core system (previous slide) that allows the devices to communicate to each other which frequency they should be on and how fast they should be hopping. Before every hop, the devices within a piconet send each other packets of information. The smaller the packets and the faster the hops, the less chance there is for devices outside of a piconet to interfere with those inside. The average Bluetooth piconet hops frequency at a rate of 79 hops per second.

Pairing

• Two devices need to be paired once to communicate with each other. Pairing usually takes place automatically once a device receives a request from another device that it is not yet paired with. Once a pairing has been established, it is remembered by the devices, which can then connect to each without user intervention. When desired, the pairing relationship can later be removed by the user.

Pairing Cont.

• During the pairing process, the two devices involved establish a relationship by creating a shared secret known as a link key. If a link key is stored by both devices they are said to be bonded. A device that wants to communicate only with a bonded device can determine the identity of the device to be sure that it is the same device it previously paired with. Once a link key has been generated, an authenticated ACL link between the devices may be encrypted so that the data that they exchange over the airwaves is protected against eavesdropping.

Pairing Cont. Cont.

• Link keys can be deleted at any time by either device. If done by either device this will implicitly remove the bonding between the devices; so it is possible for one of the devices to have a link key stored but not be aware that it is no longer bonded to the device associated with the given link key.

Major Manufacturers

• Samsung

• Sony

• Hyundai

• LG

• 3Com

• Matsushita

• Acer

• Billionton International Inc.

• Canon Inc.

• 2001 Technology Inc.

• Motorola

• Nokia

• Toshiba

• Hewlett-Packard

• Seiko Epson Corporation

• Apple, Inc.

• Casio Computer Co. Ltd.

Prices of Major Bluetooth Products

• Bluetooth Headset: $38

• Bluetooth Adapter: $15

• Bluetooth-enabled wireless phone: $80

• Bluetooth printer: $425

• Bluetooth watch: $200

• Bluetooth mouse: $35

• Bluetooth keyboard: $40

Sources

• http://www.bluetooth.com/Bluetooth/SIG/History_of_the_SIG.htm

• http://en.wikipedia.org/wiki/Bluetooth

• http://electronics.howstuffworks.com/bluetooth1.htm

• http://electronics.howstuffworks.com/bluetooth.htm

• http://www.swedetrack.com/images/bluet13.htm

• http://books.google.com/books?id=zBkEAAAAMBAJ&pg=PA31&lpg=PA31&dq=how+fast+do+bluetooth+devices+hop&source=bl&ots=o5w0r82lNa&sig=sXq3OesiiLlI8pRGqVmBVqtmigA&hl=en&ei=6hgDS7OuDJPTnAeY-vln&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=how%20fast%20do%20bluetooth%20devices%20hop&f=false

• http://www.bluetooth.com/Bluetooth/Products/Products/

‘Tis Ze End!