Bluetooth Overview

Harald I. Bluetooth (Danish Harald Bl å tand), King of Denmark between 940 and 985 AD, conquered Norway in the year 960 AD. His “ bluetooth ” was a result of eating too many blueberries. More than 1000 years later, in 1994, his nickname was used to name a wireless technology that connects cell phones or other devices without using cables. The company that took the initiative to invent the short-range, low-power, and low-cost radio technology is Ericsson. In February 1998, an industry consortium, called Special Interest Group (SIG), of Bluetooth was formed by fi ve companies — Ericsson, Nokia, IBM, Toshiba, and Intel — across three different sectors of the industry. Ericsson and Nokia were major cell phone manufacturers, IBM and Toshiba were major laptop computer manufacturers, and Intel’s strength was signal processing (in addition to computer processors). In July 1999, the Bluetooth SIG released a 1500-page specification (Bluetooth 1.0). In 2001, the first Bluetooth-enabled products, primarily cell phones and PDAs, were announced. More than 1500 companies adopted Bluetooth for their products. To date, Bluetooth has become the de facto short-range wireless technology for mobile devices. The IEEE 802.15 working group for personal area networks has adopted\ Bluetooth as one of the IEEE 802.15 standards: IEEE Std 802.15.1-2002. Other 802.15 standards are 802.15.2 for the coexistence of WPAN and wireless LAN, 802.15.3 and 802.3a for UWB, and 802.15.4 for ZigBee. The features of Bluetooth are summarized as follows:

» Short range: 10 to 100 m.
» Low cost: less than $5.
» Low power: 10 to 100 mW.
» Low data rate: 1 to 2 Mbps.

The interoperable applications of Bluetooth fall into the following categories:

» Cable replacement: Computers are notorious for having cluttered cables for various peripherals such as a keyboard, a mouse, speakers, and a headset. More and more people use an earpiece connected to a cell phone while making a call. It would be far more convenient to have wireless connections between the peripherals and the devices. Bluetooth can be used for this purpose.

» Ad hoc data networking: As more mobile devices are used by the general public, ad hoc networking capability is often desired to facilitate occasional data transfer and interaction. Bluetooth is designed to allow effortless network setup of a number of compatible devices in a short range.

It is worth noting that Bluetooth and wireless LANs are not exactly targeting the same application scenarios of wireless connectivity, even if both of them (i.e., 802.11b wireless
LANs and Bluetooth) operate at the same 2.4-GHz band. Bluetooth by and large is used for power-limited mobile devices for data transfer within a person’s reach, which is why it is considered a WPAN technology. Wireless LANs, on the other hand, provide much higher bandwidths over a longer distance but consume more power.

Source of Information : Elsevier Wireless Networking Complete 2010


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