Bluetooth devices will normally operate at 2.four GHZ
in the license free, globally available ISM radio
band. The advantage to this band includes worldwide
availability & compatibility. A disadvantage to
this however, is that the devices must share this
band with other RF emitters. This includes
automobile security systems, other wireless devices,
and other noise sources, such as microwaves.
To overcome this challenge, Bluetooth employs a
quickly frequency hopping scheme and therefore uses
shorter packets than other standards within the
ISM band. This scheme helps to make Bluetooth
communication more robust and more secure.
Frequency hopping
Frequency hopping is basically jumping from frequency
to frequency within the ISM radio band. After a
bluetooth device sends or receives a packet, it
and the device (or devices) it's communicating with
hop to another frequency before the next packet is
sent. This scheme offers three advantages:
1. Allows Bluetooth devices to use the
entirety of the available ISM band, while never
transmitting from a fixed frequency for more than a
short period of time. This helps insure that
Bluetooth conforms to the ISM restrictions on the
transmission quantity per frequency.
2. Ensures that any interference won't
last long. Any packet that doesn't arrive safely
to its destination can be resent to the next
frequency.
3. Provides a base level of security as
it's very hard for an eavesdropping device to predict
which frequency the Bluetooth devices will use
next.
The connected devices however, must agree upon the
frequency they will use next. The specification
in Bluetooth ensures this in two ways. First, it
defines a master and slave type relationship between
bluetooth devices. Next, it specifies an algorithm
that uses device specific details when
calculating the frequency hop sequences.
A Bluetooth device that operates in master mode can
communicate with up to seven devices that are set in
slave mode. To each of the slaves, the master
Bluetooth device will send its own unique address
and the value of its own internal clock. The
information sent is then used to calculate the
frequency hop sequences.
Because the master device and each of the slave
devices use the same algorithm with the same initial
input, the connected devices will invariably arrive
together at the next frequency that they have agreed
upon.
As a replacement for cable technology, it's no
wonder that Bluetooth devices are usually battery
powered, such as wireless mice and battery powered
cell phones. To conserve the power, most devices
operate in low power. This helps to give Bluetooth
devices a range of close to 5 - ten meters.
This range is far enough for wireless communication
but close enough to avoid drawing too much power
from the power source of the device.
Bluetooth And Infrared
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Bluetooth Applications
1. Wireless networking between laptops & de...
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Bluetooth Basics
The key features offered by Bluetooth include low power & low cost. The specification in Bluetooth defines a uni...
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Bluetooth Definition
The technology of Bluetooth was primarily designed to support simple wirele...
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Bluetooth Glossary
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Bluetooth In Action
Now, Bluetooth is facing stiff competition from new w...
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Bluetooth Operation
Many devices that you already known and use take advantage of this frequency band. Ga...
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Bluetooth Profiles
The profile will also define the parameter range...
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Bluetooth Security
The good news for Bluetooth users is that the security scares, l...
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Bluetooth Specifications
1. Throughout the United States and even Europe, the ra...
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Bluetooth Technical Operations
Current prototype circuits are contained on a board that is 0.nine cm square, with a much smaller circuit...
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Bluetooth Technology Intro
Capabilities ...
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Bluetooth Versions
Since the technology of Bluetooth was introduced in 1998, several specification versions have been releas...
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Bluetooth Wireless Networking
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Choosing A Bluetooth Headset
Bluetooth headsets can never be as small or as light as wired headsets, simpl...
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Connecting Many With Bluetooth
A good example is Bluetooth for cell phones. It enables mobile users to connect to their hands free headset w...
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Key Learning Points Of Bluetooth
1. Bluetooth is an energy efficient, low ove...
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The Bluetooth Solution
Bluetooth is a networking standard that will work on two ...
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The Future Of Bluetooth
Since the forming of the original group, more than 1,800 manufacturers around the...
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Using Bluetooth
Bluetooth also offers interoperability, meaning that you can use your portable Bluetooth device to...
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10 Benefits Of Bluetooth
1. Wireless ...
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Advantages And Disadvantages
In the key marketplace, of wireless and handheld devices, the closest competitor to...
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Bluetooth And Apple
Full support ...
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