Bluetooth

Bluetooth is a wireless technology that is used to transfer data between electronic devices. On comparison with other mode of wireless communication the distance of data transmission is very small. This technology has reduced the use of cords, cables, adapters and permitted the electronic devices to communicate wirelessly among each other.

Features of Bluetooth

  • Frequency     :2.4GHz
  • Range            :10m and can be extended to 100m
  • Data rate       :1mbps
  • Modulation   : Gaussian Frequency Shift Keying
  • Baseband     : FH-SS over 79 carriers(of 1MHz each), CDMA (hopping sequence from the node MAC address)
  • RFCOMM      : provides emulation of serial links (RS232). Upto 60 connections
  • Protocol       :FHSS(Frequency-Hopping Spread Spectrum)
  • Maximum serial baud rate :1382400 bps
  • Power input : +3.3V dc

Types of Bluetooth Devices

  1. Head Set
  2. In-Car Bluetooth System
  3. Bluetooth Equipped Printer
  4. Bluetooth Equipped Web
  5. Cam
  6. Bluetooth GPS System
  7. Bluetooth Key Board

Importance of Bluetooth:

  • These are available cheaply.
  • Use of Bluetooth has replaced the use of cables or cords for transferring information between electronic devices.
  • These have decreased Strain like carrying phones while talking, making hands free to do another work.
  • Mobility of Bluetooth is also very important as it doesn’t require any power outlet or internet connection or any other items.

Protocol Architecture:

  • Bluetooth is a layered protocol architecture
    • Core protocols
    • Cable replacement and telephony control protocols
    • Adopted protocols
  • Core protocols
    • Radio
    • Base band
    • Link manager protocol (LMP)
    • Logical link control and adaptation protocol (L2CAP)
    • Service discovery protocol (SDP)

FHSS (Frequency-Hopping Spread Spectrum)

  • Bluetooth uses packet-switching to send data.
  • Bluetooth sends packets of data on a range of frequencies.
  • For every session there is a master and the other is the slave.
  • The master device decides at which frequency data will travel.