Blue Tooth Technology

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  What Is Blue Tooth?

  Bluetooth is an industrial specification for wireless personal area networks (PANs). Bluetooth provides a way to connect and exchange information between devices such as mobile phones, laptops, PCs, printers, digital cameras, and video game consoles over a secure, globally unlicensed short-range radio frequency. The Bluetooth specifications are developed and licensed by the Bluetooth Special Interest Group.

  Spectrum
  Bluetooth technology operates in the unlicensed industrial, scientific and medical (ISM) band at 2.4 to 2.485 GHz, using a spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops/sec. The 2.4 GHz ISM band is available and unlicensed in most countries
  List of applications
  More prevalent applications of Bluetooth include:
  

  • Wireless control of and communication between a cell phone and a hands-free headset or car kit. This was one of the earliest applications to become popular.
  • Wireless networking between PCs in a confined space and where little bandwidth is required.
  • Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer.
  • Transfer of files between devices with OBEX.
  • Transfer of contact details, calendar appointments, and reminders between devices with OBEX.
  • Replacement of traditional wired serial communications in test equipment, GPS receivers, medical equipment and traffic control devices.
  • For controls where infrared was traditionally used.
  • Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.
  • Seventh-generation game consoles—Nintendo Wii[2], Sony PlayStation 3—use Bluetooth for their respective wireless controllers.

  Bluetooth Technology Benefits

  Why Choose Bluetooth wireless technology?
  Bluetooth wireless technology is the simple choice for convenient, wire-free, short-range communication between devices. It is a globally available standard that wirelessly connects mobile phones, portable computers, cars, stereo headsets, MP3 players, and more. Thanks to the unique concept of “profiles,” Bluetooth enabled products do not need to install driver software. The technology is now available in its fourth version of the specification and continues to develop, building on its inherent strengths — small-form factor radio, low power, low cost, built-in security, robustness, ease-of-use, and ad hoc networking abilities. Bluetooth wireless technology is the leading and only proven short-range wireless technology on the market today shipping over five million units every week with an installed base of over 500 million units at the end of 2005.

  Globally Available
  The Bluetooth wireless technology specification is available free-of-charge to our member companies around the globe. Manufacturers from many industries are busy implementing the technology in their products to reduce the clutter of wires, make seamless connections, stream stereo audio, transfer data or carry voice communications. Bluetooth technology operates in the 2.4 GHz, one of the unlicensed industrial, scientific, medical (ISM) radio bands. As such, there is no cost for the use of Bluetooth technology. While you must subscribe to a cellular provider to use GSM or CDMA, with Bluetooth technology there is no cost associated with the use beyond the cost of your device.
  Range of Devices
  Bluetooth technology is available in an unprecedented range of applications from mobile phones to automobiles to medical devices for use by consumers, industrial markets, enterprises, and more. The low power consumption, small size and low cost of the chipset solution enables Bluetooth technology to be used in the tiniest of devices. Have a look at the wide range products made available by our members in the Bluetooth product directory and the component product listing.
  Ease of Use
  Bluetooth technology is an ad hoc technology that requires no fixed infrastructure and is simple to install and set up. You don’t need wires to get connected. The process for a new user is easy – you get a Bluetooth branded product, check the profiles available and connect it to another Bluetooth device with the same profiles. The subsequent PIN code process is as easy as when you identify yourself at the ATM machine. When out-and-about, you carry your personal area network (PAN) with you and can even connect to others.
  Globally Accepted Specification
  Bluetooth wireless technology is the most widely supported, versatile, and secure wireless standard on the market today. The globally available qualification program tests member products as to their accordance with the standard. Since the first release of the Bluetooth specification in 1999, over 4000 companies have become members in the Bluetooth Special Interest Group (SIG). Meanwhile, the number of Bluetooth products on the market is multiplying rapidly. Volumes have doubled for the fourth consecutive year and are likely to reach an installed base of 500 million units by the close of 2005.
  Secure Connections
  From the start, Bluetooth technology was designed with security needs in mind. Since it is globally available in the open 2.4 GHz ISM band, robustness was built in from the beginning. With adaptive frequency hopping (AFH), the signal “hops” and thus limits interference from other signals. Further, Bluetooth technology has built-in security such as 128bit encryption and PIN code authentication. When Bluetooth products identify themselves, they use the PIN code the first time they connect. Once connected, always securely connected
  How Bluetooth Technology Works
  Bluetooth wireless technology is a short-range communications system intended to replace the cables connecting portable and/or fixed electronic devices. The key features of Bluetooth wireless technology are robustness, low power, and low cost. Many features of the core specification are optional, allowing product differentiation.
  The Bluetooth core system consists of an RF transceiver, baseband, and protocol stack. The system offers services that enable the connection of devices and the exchange of a variety of data classes between these devices.
  
  Overview of Operation
  The Bluetooth RF (physical layer) operates in the unlicensed ISM band at 2.4GHz. The system employs a frequency hop transceiver to combat interference and fading, and provides many FHSS carriers. RF operation uses a shaped, binary frequency modulation to minimize transceiver complexity. The symbol
  rate is 1 Megasymbol per second (Msps) supporting the bit rate of 1 Megabit per second (Mbps) or, with Enhanced Data Rate, a gross air bit rate of 2 or 3Mb/s. These modes are known as Basic Rate and Enhanced Data Rate respectively.
  During typical operation, a physical radio channel is shared by a group of devices that are synchronized to a common clock and frequency hopping pattern. One device provides the synchronization reference and is known as the master. All other devices are known as slaves. A group of devices synchronized in this fashion form a piconet. This is the fundamental form of communication for Bluetooth wireless technology.
  Devices in a piconet use a specific frequency hopping pattern which is algorithmically determined by certain fields in the Bluetooth specification address and clock of the master. The basic hopping pattern is a pseudo-random ordering of the 79 frequencies in the ISM band. The hopping pattern may be adapted to exclude a portion of the frequencies that are used by interfering devices. The adaptive hopping technique improves Bluetooth technology co-existence with static (non-hopping) ISM systems when these are co-located.
  The physical channel is sub-divided into time units known as slots. Data is transmitted between Bluetooth enabled devices in packets that are positioned in these slots. When circumstances permit, a number of consecutive slots may be allocated to a single packet. Frequency hopping takes place between the transmission or reception of packets. Bluetooth technology provides the effect of full duplex transmission through the use of a time-division duplex (TDD) scheme.
  Above the physical channel there is a layering of links and channels and associated control protocols. The hierarchy of channels and links from the physical channel upwards is physical channel, physical link, logical transport, logical link and L2CAP channel.
  Within a physical channel, a physical link is formed between any two devices that transmit packets in either direction between them. In a piconet physical channel there are restrictions on which devices may form a physical link. There is a physical link between each slave and the master. Physical links are not formed directly between the slaves in a piconet.
  The physical link is used as a transport for one or more logical links that support unicast synchronous, asynchronous and isochronous traffic, and broadcast traffic. Traffic on logical links is multiplexed onto the physical link by occupying slots assigned by a scheduling function in the resource manager.
  A control protocol for the baseband and physical layers is carried over logical links in addition to user data. This is the link manager protocol (LMP). Devices that are active in a piconet have a default asynchronous connection-oriented logical transport that is used to transport the LMP protocol signaling. For historical reasons this is known as the ACL logical transport. The default ACL logical transport is the one that is created whenever a device joins a piconet. Additional logical transports may be created to transport synchronous data streams when this is required.
  The link manager function uses LMP to control the operation of devices in the piconet and provide services to manage the lower architectural layers (radio layer and baseband layer). The LMP protocol is only carried on the default ACL logical transport and the default broadcast logical transport.
  Above the baseband layer the L2CAP layer provides a channel-based abstraction to applications and services. It carries out segmentation and reassembly of application data and multiplexing and de-multiplexing of multiple channels over a shared logical link. L2CAP has a protocol control channel that is carried over the default ACL logical transport. Application data submitted to the L2CAP protocol may be carried on any logical link that supports the L2CAP protocol.
  

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