Bluetooth technology specifies a short-range two-way radio link that enables communication between PCs, cell phones, PDAs, and other computer, electronic, and home theater equipment. With Bluetooth, you can easily sync calendar or contact data between a PDA and laptop, talk on the phone hands-free, or print wirelessly. It is a wire replacement technology like infrared, but it offers many advantages over infrared.
The Bluetooth specification focuses on keeping costs low, power consumption minimal, and size small. Its low power consumption means that it can be used in battery-powered devices. Bluetooth offers faster data speeds and greater transmission distances compared to infrared, and there are no line-of-site restrictions. It operates on the 2.4 GHz radio frequency, ensuring worldwide operability.
Story
Bluetooth is named after a 10th century Danish king, Harald Blatand (Harld Bluetooth), known for uniting warring groups in present-day Norway, Sweden, and Denmark. It was originally developed by Ericsson, but is now managed by the Bluetooth Special Interest Group (SIG).
Bluetooth SIG is an industry group with members from the telecommunications, computing, and chip manufacturing industries. To date, more than 2000 companies are members. Bluetooth SIG oversees a qualification program to ensure standard compliance and interoperability with other Bluetooth devices. Any device bearing the Bluetooth logo has successfully completed interoperability testing.
Technical details
Speed: Bluetooth supported raw data rate is 1 Mbps. Actual data rates are 432 kbps for full-duplex and 721 kbps for asymmetric transmission.
Frequency: Bluetooth uses the 2.4 GHz unlicensed ISM (Industrial, Scientific and Medical) band. In most countries this band is available. In some countries it is reserved for military use, but even these countries are moving to make the band available for general use. Because Bluetooth shares the same frequency range as 802.11b WLAN products, these two technologies cannot operate in the same space under some conditions.
Security: Bluetooth is designed to be as secure as a cable using 128-bit encryption and authentication. Applications can also build their own security in addition to the Bluetooth connection.
Transmission Distance: Typical Bluetooth range is up to 10m. The range depends on the kind of radio power used. A class 2 radio has a typical range of 10 m. The more powerful classes support longer ranges and have higher power outputs. Most devices use a class 2 radio and mobile devices, such as cell phones, where low power consumption is crucial, can only use a class 2 radio.
Architecture: With Bluetooth, up to 8 devices can be connected simultaneously. A piconet is the term for a collection of connected Bluetooth devices in an ad hoc manner. All devices are units of pairs, but one device acts as a master and the others as slaves during the piconet connection. Each piconet can support up to 3 full-duplex voice devices. Within an area of 10 m, there can be up to 10 piconets.
Applications
Bluetooth is becoming the preferred wireless technology in WPAN (Wireless Personal Area Network). Personal applications include:
– Users can connect PC to transfer files.
– Workers can collaborate on the same document using Microsoft NetMeeting.
– Users can connect to a printer wirelessly.
– Users can synchronize data between a handheld PDA and a laptop.
– Users can listen to music through wireless headphones.
– Users can talk on their mobile phone with wireless headsets.
– Users can connect their laptops to the Internet using their mobile phone’s GPRS or UMTS network.
