A popular wireless personal area network (WPAN) for short-range transmission of digital voice and data. Using omnidirectional radio waves, Bluetooth transmits through walls and other non-metal barriers. Although the term is practically synonymous with cellphone headsets and in-vehicle, hands-free telephony, Bluetooth is also used in myriad applications, including keyboards, mice and game controllers (for more details, see Bluetooth profiles). Supporting point-to-point and multipoint architectures (see piconet), there were more than three billion Bluetooth devices on the market by 2011.
Why the Name?
The name comes from ancient King Harald Blatan of Denmark (Blatan in Danish translates to blue tooth in English). Sweden-based telecom company Ericsson developed the technology and was co-founder in 1998 of the Bluetooth Special Interest Group governing body (www.bluetooth.com). Bluetooth is also standardized as an IEEE wireless personal area network (see 802.15). See Bluetooth glossary.
Bluetooth Specifications
Bluetooth transmits in the same unlicensed 2.4 GHz band as Wi-Fi, but with a different transmission method. It uses frequency hopping spread spectrum (FHSS), which changes its signal randomly to one of 79 channels 1,600 times per second. If there is interference from other devices, transmission continues, but speed is downgraded. See spread spectrum.
Bluetooth EDR and HS
Bluetooth 2.0 + EDR (Enhanced Data Rate) increases the data rate from 1 to 3 Mbps and avoids channels that are interfering with other wireless devices.
Bluetooth 3.0 + HS (High Speed) uses a nearby Wi-Fi link for speeds up to 24 Mbps. Bluetooth HS establishes the connection but uses Wi-Fi for data transport. Future versions of Bluetooth were expected to use UWB transmission (see WiMedia Alliance).
Bluetooth Low Energy and Bluetooth Classic
Version 4 of the Bluetooth specification added Nokia's Wibree low-power technology, renamed Ultra Low Power (ULP) Bluetooth and later Bluetooth Low Energy. Using up to a quarter of the power of Bluetooth at 1 Mbps, Bluetooth Low Energy enables devices with tiny coin-cell batteries to last for more than a year. The previous Bluetooth specifications were renamed Bluetooth Classic. See Bluetooth glossary.
BLUETOOTH VERSIONS
Data
Rate
Version (Mbps)
1.2 1
2.0 + EDR 3
3.0 + HS 24 (Wi-Fi)
4.0 All versions
BLUETOOTH POWER AND RANGES
Maximum Approximate
Power Range
Class (mW) (meters)
1 100 mW 100 m
2 2.5 mW 10 m
3 1 mW 1 m
All Bluetooth cellphone users are employing two wireless technologies: Bluetooth between ear and cellphone and the carrier's transmission technology between cellphone and cell tower (see
This "gamepad" from Sony uses Bluetooth to communicate with the PlayStation3 game console. See
The stylized "B" displayed on this cellphone means it has been synchronized with a Bluetooth device.
|
