| Introduction Of Bluetooth |
Bluetooth is an industrial specification for wireless personal area
networks (PANs). Bluetooth provides a way to connect and exchange information
between devices such as mobile phones, laptops, PCs, printers, digital cameras,
and video game consoles over a secure, globally unlicensed short-range radio
frequency. The Bluetooth specifications are developed and licensed by the
Bluetooth Special Interest Group.
Uses
Bluetooth is a standard and communications protocol primarily designed for
low power consumption, with a short range (power-class-dependent: 1 meter, 10
meters, 100 meters)[1] based on
low-cost transceiver microchips in each device.
Bluetooth enables these devices to communicate with each other when they are
in range. The devices use a radio communications system, so they do not have to
be in line of sight of each other, and can even be in other rooms, as long as
the received transmission is powerful enough.
| Class |
Maximum Permitted Power
(mW/dBm) |
Range
(approximate) |
| Class 1 |
100 mW (20 dBm) |
~100 meters |
| Class 2 |
2.5 mW (4 dBm) |
~10 meters |
| Class 3 |
1 mW (0 dBm) |
~1 meter |
It has to be noted that in most cases the effective range of class 2 devices
is extended if they connect to a class 1 transceiver, compared to pure class 2
network. This is accomplished by higher sensitivity and transmitter power of the
Class 1 device. The higher transmitter power of Class 1 device allows higher
power to be received by the Class 2 device. Furthermore, higher sensitivity of
Class 1 device allows reception of much lower transmitted power of the Class 2
devices. Thus, allowing operation of Class 2 devices at much higher distances.
Devices that use a power amplifier on the transmit, have improved receive
sensitivity, and highly optimized antennas are available that routinely achieve
ranges of 1km within the Bluetooth
Class 1 standard.
| Version |
Data Rate
|
| Version 1.2 |
1 Mbit/s |
| Version 2.0 + EDR |
3 Mbit/s |
WiMedia Alliance
(proposed) |
53 - 480 Mbit/s |
|
