Bluetooth Gyaan

What is it?

A short-range, non-line-of-sight wireless technology operating over a typical distance of around 30 feet and geared towards easy data exchange between fixed and mobile electronic devices.

Who dunnit?

Developed by Jaap Haartsen and Sven Mattisson from Ericsson in 1994 as an alternative to wired connections in common products like phones and headsets or computers, keyboards and mice.

Several leading companies like Ericsson, Microsoft, Intel, Motorola, Nokia, Toshiba etc formed the “Special Interest Group” (SIG) codenamed “Bluetooth” in May, 1998 to promote the technology as a way to make their products compatible.

SIG initiated the “Bluetooth Innovation World Cup” in June, 2009 for three years to encourage new innovations and ideas in various domains utilizing Bluetooth applications.

Interestingly, the name “Bluetooth” derives its origin from 10th century Danish king, Harald Blatand (or Harold Bluetooth in English) who was instrumental in uniting hostile tribes just as Bluetooth technology is developed to allow collaboration between differing industries!!

Technology

Any wireless technology employs a modulation scheme to transmit the desired signal by piggybacking it on a high-frequency carrier wave. The modulation scheme adopted by Bluetooth is “Adaptive Frequency-hopping Spread Spectrum” (AFH).

Generally speaking, “Frequency-hopping Spread Spectrum” technique uses a carrier wave that hops in a random but predictable sequence known to both transmitter and receiver. In Bluetooth these random values may be typically 79 in number hopping as frequently as 1600 times per second to avoid radio frequency interference with similar devices. AFH furthermore improves resistance to interference by avoiding crowded or unwanted frequencies in the hopping sequence.

Bluetooth operates between 2.402 GHz -2.480 GHz in the unlicensed ISM (Industrial-Scientific-Medical) frequency band and is primarily designed for low power consumption typically around 1 milliwatt. It provides three different “Classes” of service depending on the range of communication varying between 1, 10 and 100 meters. Also it is available in different versions with the “Enhanced Data Rate (EDR) 2.0” version offering as high as 3 Mbps data capacity.

Bluetooth operates over a small area known as Personal Area Network (PAN) or Piconet. It is a packet-based protocol following “Master-Slave” architecture where a Master can communicate with up to 7 slaves in the Piconet; all devices sharing the Master’s clock ticking at 312.5 µs slot intervals. Packets may be 1, 3 or 5 slots long but the master always transmits in even slots while the slave in odd slots. Transmission can however be either half-duplex or full-duplex but uniquely recognized in the Piconet.

Bluetooth doesn't require you to think about setting up a connection or to push any buttons. When two or more Bluetooth devices enter the desired range, they begin to communicate automatically in order to setup the Piconet. They take care of the entire setup and discovery process, and you can go about your business.

In order for one Bluetooth device to connect to another, both devices must share at least one common among the many Bluetooth profiles. For example, a Bluetooth enabled printer is going to support the Basic Printing Profile but a PDA with Bluetooth technology supports several profiles, such as the Synchronization Profile, LAN Access Profile, File Transfer Profile and others. According to SIG such profiles must include some essential information like recommended user interface formats and Bluetooth protocol stack.

Bluetooth offers several security modes, and device manufacturers determine which mode to include in the gadget. Still some recent issues like “Bluejacking”, “Bluebugging”,"Bluesnarfing" and “Car Whisperer” have cropped up which are dealt with firmware upgrades from manufacturers.

Applications

Bluetooth has now become a commonplace technology in almost all electronic gadgets these days. The typical symbol signifying that Bluetooth is enabled can be found in all mobiles and laptops allowing us to use hands-free headset and wireless mouse, keyboard, headphones etc. Since its inception it has continued to mature as a universal standard and has allowed new connections which weren’t possible using wires earlier, like connecting a mobile phone to car stereo, or printing a picture directly from your camera phone.

Microsoft, Apple and Linux have supported Bluetooth stacks since many years. Nowdays, even if notebooks or laptops don't offer embedded Bluetooth chips, there is choice of using Bluetooth dongles for plug-and-play service.

Today Bluetooth is even embedded in products like PlayStation, modems, high-end watches etc. As more and more devices begin to exploit the advantages of Bluetooth, consumer electronics manufacturers will be increasingly eager to make their products compatible. With continuous effort of around 13,000 members in the SIG, without doubt Bluetooth is here to stay.

Check out a list of top 5 Bluetooth gadgets:
http://electronics.howstuffworks.com/bluetooth-gadgets.htm