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How Bluetooth Works
in the license free, globally available ISM radio band. The advantage to this band includes worldwide availability and 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 fast 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 information 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 always 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 around 5 - 10 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.
10 Benefits Of Bluetooth |
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Bluetooth And Apple The new Apple powerbook G4 are among the first computers to offer Bluetooth technology 2.0+EDR. The 2.0+EDR technology, which still backwards compatible with 1.0, is up to three times faster than previous versions, offering maximum data... Bluetooth Glossary Below, you'll find a list of the most used terms in Bluetooth technology. They can serve as a look up, or to help you learn more about Bluetooth terms in general. 2 in 1 handset The situation where a subscriber's handset is acting ... Bluetooth In Action In the United States, Bluetooth gets absolutely no respect. It is however, becoming more and more common in notebooks, PDAs, and especially cell phones. Bluetooth will provide wireless users a way to transmit small amounts of data over... Bluetooth Operation The networking standards of Bluetooth will transmit data via low power radio frequency. Bluetooth communicates on a 2.45 GHz frequency. This very band of frequency has been set aside by international agreement for the use of industrial and... Bluetooth Security These days, all communication technology faces the issue of privacy and identity theft, with Bluetooth being no exception. Almost everyone knows that email services and networks require security. What users of Bluetooth need to realize is... Bluetooth Specifications Below, you'll find several specifications for the well known Bluetooth: 1. Throughout the United States and even Europe, the range of frequency is 2,400 - 2,483.5 MHZ, with 79 1-MHz RF (radio frequency) channels. The frequency range... Bluetooth Versions Version 1.1 and earlier Since the technology of Bluetooth was introduced in 1998, several specification versions have been released. Versions 1.0 and 1.0B had too many issues and problems for manufacturers to develop devices for... Choosing A Bluetooth Headset Creating a good wireless headset for Bluetooth is actually difficult to do. The regular wired headsets are easy to design - with ranging styles. Bluetooth headsets can never be as small or as light as wired headsets, simply because it... How Bluetooth Works Bluetooth devices will normally operate at 2.4 GHZ in the license free, globally available ISM radio band. The advantage to this band includes worldwide availability and compatibility. A disadvantage to this however, is that the devices... The Future Of Bluetooth Because it meets the basic needs of connectivity in close range, Bluetooth has a very bright future ahead of it. Bluetooth is actually the result of initiatives from nine leading communications and computer industry giants, including...
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