Bluetooth

• Bluetooth is a wireless technology standard for exchanging data over short distances from fixed and mobile devices, and building personal area networks (PANs).
• Bluetooth uses short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz.
• Who is Bluetooth?

  Harold Blaatand “Bluetooth” II
• In 1994 – need for low power consumption wireless devices to substitute for cable
• Ericsson is the driving force behind Bluetooth
• In 1998, Ericsson, Nokia, IBM, Toshiba, Intel formed the Bluetooth Special Interest Group (SIG)
• Year 1999 – Release of Bluetooth protocol
• 2002 – IEEE adopted Bluetooth standard, 802.15 working group
• Inventor of Bluetooth

  Ericsson (1994)
• Bluetooth is managed by Bluetooth Special Interest Group
• Bluetooth is originally conceived as a wireless alternative to data cables
• Industrial applications of Bluetooth

  Mobile personal area networks
• Compatible hardware of Bluetooth

  Mobile phones, Personal computers, Laptop computers, Gaming consoles
• Physical range of Bluetooth

  Up to 60 m
• Bluetooth IEEE Standard Designation

  802.15.1
• What does Bluetooth do for you?

  1. cable replacement
  2. data/voice access points
  3. personal ad-hoc networks
• A network of devices connected in an ad hoc fashion using Bluetooth technology

  Piconet
• A piconet is formed when at least two devices, such as a portable PC and a cellular phone, connect
• Piconet can support up to eight devices
• When piconet is formed, one device acts as the master while the others act as slaves
• A piconet is sometimes called a PAN
• Two or more Bluetooth units sharing the same channel form a piconet
• Slaves in a piconet can only have links to the master
• Slaves cannot directly transmit data to one another
• Master acts as a switch for the piconet and all traffic must pass through master
• Any device can be either a master or a slave within a piconet and they can change roles at any point in a connection when a slave wants to take over a master's role
• Every Bluetooth device has its own clock and can be uniquely identified by its Bluetooth device address
• Slaves in a piconet use master's Bluetooth device address and clock to determine the frequency hopping sequence
• Slaves synchronize with master's clock for duration of the connection
• Master also controls when devices transmit data, since slaves can only transmit when scheduled by a master
• Master controls how total available bandwidth is distributed among the slaves
• Scatternet is a group of independent and non-synchronized piconets that share at least one common Bluetooth device
• Bluetooth devices must have point-to-multipoint capability to engage in scatternet communication
• There may be a maximum of 10 fully loaded piconets in a scatternet
• Scatternet is a more recent use of Bluetooth
• A set of two or more interconnected piconets form scatternets
• A Bluetooth unit can be a slave in two or more piconets, but it can be a master in only one
• Bluetooth is a standard for tiny, radio frequency chips that can be plugged into your devices
• These chips were designed to take all of the information that your wires normally send, and transmit it at a special frequency to something called a receiver Bluetooth Chip
• Bluetooth uses packet-switching to send data