Bluetooth is a standard protocol for unifying voice and data among a wide range of electronic devices. The ability to do this came about as radios decreased their cost and power consumption. As a result it became feasible to embed them into many varied types of electronic devices. Bluetooth is one of two types of radio standards that have been developed to underpin this trend.
The Bluetooth standard was jointly developed
The Bluetooth standard was developed jointly by 3 Corn, Ericsson, Intel, IBM, Lucent, Microsoft, Motorola, Nokia, and Toshiba.
The standard has now been adopted by over 1,300 manufacturers, and many consumer electronic products incorporate Bluetooth. These include wireless headsets for mobile phones, wireless USB or RS232 connectors, wireless PCMCIA cards and wireless set-top boxes.
Bluetooth provides for short range connections between devices
Bluetooth radios provide short-range connections between wireless devices along with basic networking capabilities. The Bluetooth standard is based on a tiny microchip inserted into a radio transceiver that is built into digital devices. The transceiver replaces the connecting cable for devices such as mobile phones, laptop and tablet computers, portable printers and projectors, and network access points. Bluetooth is used mainly for short-range communications of up to 10m for example such as, from a mobile phone to a wireless headset or built in car hands free system or from a laptop to a nearby. Its normal range of operation is 10 m although this can be increased up to 100 m by increasing the transmission power.
Bluetooth is named after King Harald I Bluetooth of Denmark
Bluetooth is named after an old king of Denmark, ‘King Harald I Bluetooth’ who united Denmark and Norway during his reign from 940 and 985 AD. His name and cause were inspiration for today’s use, as the modern Bluetooth is designed to unite devices via radio connections.
Bluetooth operates in the unlicenced 2.4-GHz radio frequency band
Bluetooth operates in the unlicensed 2.4-GHz frequency band, so it can be used worldwide free of usage charge and without any licensing issues. This band is also be used by non-Bluetooth Devices. The Bluetooth standard provides one asynchronous data channel at 723.2 kbps. In this mode, also known as Asynchronous Connection-Less (ACL), there is a reverse channel with a data rate of 57.6 kbps. The specification also allows up to three synchronous channels each at a rate of 64 kbps. This mode, also known as Synchronous Connection Oriented (SCO), is mainly used for voice applications such as headsets but can also be used for data. These different modes result in an aggregate hit rate of approximately 1 Mbps. Routing of the asynchronous data is done via a packet switching protocol based on frequency hopping at 1600 hops per second. There is also a circuit switching protocol for the synchronous data.
Bluetooth uses frequency hopping for multiple access
Bluetooth uses frequency hopping for multiple access with a carrier spacing of 1 MHz. Usually, up to eighty different frequencies are used for a total bandwidth of 80 MHz. At any given time, the bandwidth available is 1 MHz, with a maximum of eight devices sharing the bandwidth.
Different hopping patterns can simultaneously share the same 80-MHZ bandwidth. Collisions or overlaps will occur when devices in different piconets, or tiny wireless networks, that arc on different logical channels happen to use the same hop frequency at the same time. As the number of piconets in an area increases, the number of collisions or overlaps in signals increases and performance degrades.
Bluetooth is in common use today
Bluetooth is in common use today as a short range connection between electronic devices and can be seen in many applications such as from a mobile phone to a wireless headset or built-in car hands free system or from a laptop to a nearby printer, synchronising a mobile phone or PDA to a desktop computer or even communication between mobile phones. Bluetooth is now ubiquitous in the modern world.