Wednesday, 22 February 2012

what is wireless communication?

          Wireless communication is the transfer of information over a distance without the use of electrical conductors or wires.
          The term "Wireless" came into public use to refer to a radio receiver or transceiver (a dual purpose receiver and transmitter device), establishing its usage in the field of wireless telegraphy early on; now the term is used to describe modern wireless connections such as in cellular networks and wireless broadband Internet. It is also used in a general sense to refer to any type of operation that is implemented without the use of wires, such as "wireless remote control", "wireless energy transfer", etc. regardless of the specific technology (e.g., radio, infrared, ultrasonic, etc.) that is used to accomplish the operation.


          The distances involved may be short (a few meters as in television remote control) or very long (thousands or even millions of kilometers for radio communications). When the context is clear the term is often simply shortened to wireless. Wireless communications is generally considered to be a branch of telecommunications.
          Wireless communications encompasses various types of fixed, mobile, and portable two way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones.
The term "wireless" has become a generic and all-encompassing word used to describe communications in which electromagnetic waves or RF carry a signal over part or the entire communication path. Common examples of wireless equipment in use today include:
  • Land Mobile Radio and Specialized Mobile Radio typically used by business, industrial and Public Safety entities
  • Consumer Two Way Radio
  • The Amateur Radio Service
  • Consumer and Professional Marine VHF Radios
  • Cellular Telephones and Pagers
  • Global Positioning System (GPS)
  • Cordless Computer Peripherals
  • Cordless Telephone Sets
  • Satellite Television
  • Wireless Gaming
Wireless communication may be via: radio frequency communication, microwave communication, for example long-range line-of-sight via highly directional antennas, or short-range communication infrared(IR), short-range communication, for example from remote controls or via IRDA. Applications may involve point-to-point communication, point-to-multipoint communication, broadcasting , cellular networks and other wireless networks.
The term "wireless" should not be confused with the term "cordless", which is generally used to refer to powered electrical or electronic devices that are able to operate from a portable power source (e.g., a battery pack) without any cable or cord to limit the mobility of the cordless device through a connection to the mains power supply. Some cordless devices, such as cordless telephones, are also wireless in the sense that information is transferred from the cordless telephone to the telephone's base unit via some type of wireless communications link. This has caused some disparity in the usage of the term "cordless", for example in Digital Enhanced Cordless Telecommunications.
In the last 50 years, wireless communications industry experienced drastic changes driven by many technology innovations.
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