Bluetooth technology specifies a short-range, bi-directional radio link that enables communication between personal computers, cell phones, PDAs, and other computing, electronics, and home theater devices. With Bluetooth, you can easily synchronize contacts or calendar data between a PDA and a laptop, make hands-free calls or print wirelessly. It’s a cable 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. Due to its low power consumption, it can be used in battery-powered devices. Bluetooth offers faster data rates and longer transmission distances compared to infrared, and there are no location restrictions. It works on the 2.4 GHz radio frequency and thus ensures worldwide usability.
Bluetooth is named after a 10th-century Danish king, Harald Blatand (Harld Bluetooth), who was known for uniting warring groups in modern-day Norway, Sweden, and Denmark. It was originally developed by Ericsson but is now managed by the Bluetooth Special Interest Group (SIG).
The Bluetooth SIG is an industry group with members from the telecommunications, computer and chip manufacturing industries. To date, over 2000 companies are members. The Bluetooth SIG oversees a qualification program to ensure compliance with the standard and interoperability with other Bluetooth devices. Any device bearing the Bluetooth logo has successfully completed the interoperability test.
Speed: The gross data rate supported by Bluetooth is 1 Mbit/s. Actual data rates are 432 kbps full duplex and 721 kbps asymmetric.
Frequency: Bluetooth uses the unlicensed ISM (Industrial, Scientific, and Medical) band at 2.4 GHz. This band is available in most countries. It is reserved for military use in some countries, but even those countries are making efforts to make the tape available for general use. Because Bluetooth uses the same frequency range as 802.11b wireless products, these two technologies cannot operate in the same room under certain conditions.
Security: Bluetooth is as secure as cable with authentication and 128-bit encryption. Applications can also base their own security on the Bluetooth connection.
Transmission range: The typical range of Bluetooth is up to 10 m. The range depends on the radio power class used. A Class 2 radio has a typical range of 10m. Higher performance classes support longer ranges and have higher output powers. Most devices use a Class 2 radio, and mobile devices such as cell phones, where low power consumption is critical, can only use a Class 2 radio.
Architecture: With Bluetooth, up to 8 devices can be connected at the same time. A piconet is the term for a collection of Bluetooth devices connected in an ad hoc manner. All devices are peer entities, but one device acts as the master and the other slaves for the duration of the piconet connection. Each piconet can support up to 3 full-duplex voice devices. There can be up to 10 piconets within a 10m range.
Bluetooth is emerging as the wireless technology of choice in WPAN (Wireless Personal Area Network). Personal applications include:
– Users can connect PCs to transfer files.
– Collaborators can collaborate on the same document using Microsoft NetMeeting.
– Users can connect to a printer wirelessly.
– Users can synchronize data between a portable PDA and a laptop.
– Users can listen to music through a wireless headset.
– Users can talk on their mobile phone using a wireless headset.
– Users can connect their laptops to the Internet via their mobile phone’s GPRS or UMTS network.