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Bluetooth is one of the current generation of wireless data transmission technologies.
It is placed roughly in the same category as WiMax, IrDA and Ultra Wideband.
It was created as an open standard by the Bluetooth Special Interest Group
consortium formed by Ericsson, IBM, Intel, Toshiba and Nokia in 1998.
For transmission, this technology takes advantage of the unlicensed 2.4ghz radio spectrum.
This comes with several advantages and disadvantages.
Picking from the first there are:
Being useable everywhere, with no need to license the frequencies.
The technology used is already familiar and has reached widespread use allowing for
efficient and low cost production.
Disadvantages are:
The open radio band is already used by various devices, mostly consumer electronics,
such as: Car and house alarms, baby monitors, cellphones, toys, microwave ovens , PDAs,
and other wireless networking technologies such as WiMax that generate a lot of
jamming and electrical noise.
To counter that, bluetooth uses a technique called "Adaptive Frequency-hopping Spread
Spectrum". It's main idea is avoiding interference by using only a part "Slice" of its
operational spectrum at any single tine, which allows it to divide it into multiple cha-
-nnels. The channels can be independently selected and used and most bluetooth implemen-
-tations will select them dynamically depending on which one turns out to give the best
signal. It allows bluetooth to efficiently share its spectrum with other devices.
Bluetooth is best used with devices designed for so called "Personal Area Networks".
These are computer networks used for communication among devices close to one person,
that can interoperate and share services easily, even without or with minimal need of manual
configuration by the user.
Compared to devices normally used in networking LANs, WANs ,etc/, these have very different
requrements of bandwidth, response and uptime.
To mark bluetooth for this scope and to set it apart from other competing wireless technologies,
the bluetooth standard also defines protocols and communication in addition to the electrical
specification. These are modular, optional parts, "Profiles". Each defines a number of services
and indicates a device's capabilities. Its use guarantees interoperability, even between devices
created by different vendors.
To allow bluetooth devices this type of service sharing the standard also predefines a
networking topology. Up to eight can be lined together into "Piconets". A Piconet is an ad-hoc,
peer-to-peer network from and to which devices can freely connect. To enable connecting a larger
number of peers, multiple Piconets can also be lined into a bigger network, Scatternet.
Thus a user is able connect various various gadgets, home appliances,... using different Profiles,
for example Generic Access, Human Interface Device, Audio/Video Remote Control, and link their
capabilities. For example, a PDA might use a TV's video streaming service, send it to a cellphone via
protocols defined inside its Object Push Profile, and in turn have the cellphone transmit the video
data via E-mail or MMS message.
Definition of transmission and protocos in the Core standard allows bloetooth to be updated
and evolve with time. Future planned updates are planned, using concepts such as Automatic Topology
Management, a method of configuring networks transparent to the users, Quality of Service management,
allowing the network to differentiate between types of traffic based on priority and Channel Broadcasting.