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Information about Wireless

For the use of the term in networking, see Wireless networking. For the British rock band, see Wireless (band).
The term wireless is normally used to refer to any type of electrical or electronic operation which is accomplished without the use of a "hard wired" connection. Wireless communication is the transfer of information over a distance without the use of electrical conductors or "wires".[1] 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.

IT. It encompasses 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 and keyboards, satellite television and cordless telephones.

Introduction

Enlarge picture
Handheld wireless radios such as this Maritime VHF radio transceiver use electromagnetic waves to implement a form of wireless communications technology.
Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g., radio transmitters and receivers, remote controls, computer networks, network terminals, etc.) which use some form of energy (e.g. radio frequency (RF), infrared light, laser light, visible light, acoustic energy, etc.) to transfer information without the use of wires.[2] Information is transferred in this manner over both short and long distances.

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, or
  • 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.

History

Further information: History of radio


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.

Early wireless work

David E. Hughes, eight years before Hertz's experiments, induced electromagnetic waves in a signalling system. Hughes transmitted Morse code by an induction apparatus. In 1878, Hughes's induction transmission method utilized a "clockwork transmitter" to transmit signals. In 1885, T. A. Edison uses a vibrator magnet for induction transmission. In 1888, Edison deploys a system of signalling on the Lehigh Valley Railroad. In 1891, Edison attains the wireless patent for this method using inductance (U.S. Patent 465,971 ).

In the history of wireless technology, the demonstration of the theory of electromagnetic waves by Heinrich Rudolf Hertz in 1888 was important.[3][4] The theory of electromagnetic waves were predicted from the research of James Clerk Maxwell and Michael Faraday. Hertz demonstrated that electromagnetic waves could be transmitted and caused to travel through space at straight lines and that they were able to be received by an experimental apparatus.[3][4] The experiments were not followed up by Hertz and the practical applications of the wireless communication and remote control technology would be implemented by Nikola Tesla.

The electromagnetic spectrum

Light, colors, AM and FM radio, and many popular electronic devices all work on the electromagnetic spectrum. In the US the frequencies that are available for use for communication are treated as a public resource and are regulated by the Federal Communications Commission (FCC). This determines which frequency ranges can be used for what purpose and by whom. In the absence of such control, chaos might result if, for example, airlines didn't have specific frequencies to work under and a ham radio operator was interfering with the pilot's ability to land an airplane. Wireless communication spans the spectrum from 9 kHz to 300 GHz.

Applications of wireless technology

Security systems

Wireless technology may supplement or replace hard wired implementations in security systems for homes or office buildings. The operations that are required (e.g., detecting whether a door or window is open or closed) may be implemented with the use of hard wired sensors or they may be implemented with the use of wireless sensors which are also equipped with a wireless transmitter (e.g., infrared, radio frequency, etc.) to transmit the information concerning the current state of the door or window.

Television remote control

Some televisions were previously manufactured with hard wired remote controls which plugged in to a receptacle or jack in the television whereas more modern televisions use wireless (generally infrared) remote control units.

Cellular telephones

Perhaps the best known example of wireless technology is the cellular telephone. These instruments use radio waves to enable the operator to make phone calls from many locations world-wide. They can be used anywhere that there is a cellular telephone site to house the equipment that is required to transmit and receive the signal that is used to transfer both voice and data to and from these instruments. (For more information see mobile phones).

Wireless communication

Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or the entire communication path. Common examples of wireless equipment in use today include:
  • Cellular phones and pagers: provide connectivity for portable and mobile applications, both personal and business.
  • Global Positioning System (GPS): allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth.
  • Cordless computer peripherals: the cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless.
  • Cordless telephone sets: these are limited-range devices, not to be confused with cell phones.
  • Satellite television: allows viewers in almost any location to select from hundreds of channels.
Wireless networking is used to meet a variety of needs. Perhaps the most common use is to connect laptop users who travel from location to location. Another common use is for mobile networks that connect via satellite. A wireless transmission method is a logical choice to network a LAN segment that must frequently change locations. The following situations justify the use of wireless technology:
  • To span a distance beyond the capabilities of typical cabling,
  • To avoid obstacles such as physical structures, EMI, or RFI,
  • To provide a backup communications link in case of normal network failure,
  • To link portable or temporary workstations,
  • To overcome situations where normal cabling is difficult or financially impractical, or
  • To remotely connect mobile users or networks.

Environmental concerns and health hazards

Recently there have been concerns risen and research conducted concerning usage of wireless communications and its possible relation to poor concentration, memory loss, nausea, premature senility and even cancer.[5][6][7]

Categories of wireless implementations, devices and standards

References

1. ^ The SINTEF Group, The Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology
2. ^ ATIS Committee T1A1 Performance and Signal Processing. ANS T1.523-2001, Telecom Glossary 2000 [1]
3. ^ Story, Alfred Thomas (1904). A story of wireless telegraphy. New York, D. Appleton and Co.. 
4. ^ Eugenii Katz, "Heinrich Rudolf Hertz".
5. ^ "Electromagnetic fields". World Health Organization. Last retrieved September 24, 2007.
6. ^ "Consensus Statement on Electromagnetic Radiation (Draft)". Collaborative on Health and the Environment. October 10, 2006.
7. ^ United Kingdom National Physics Laboratory report.

See also

General: History of radio, Timeline of radio, Digital radio, Radio resource management (RRM)
Wireless: Wireless telegraphy, Wireless campus, Wireless energy transfer, True wireless, Wireless security
Other: PAN, comparison of wireless data standards

External links

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Please [ improve this article] by removing excessive or inappropriate external links. Please remove this tag when this is done. (talk)

Patents

While the term wireless network may technically be used to refer to any type of network that is wireless, the term is most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a
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wireless are an Indie (music)/Rock (music) group formed in the UK in 2000 by Paul Mayhew (Lead Vocals/Guitar), Daniel Turner (Bass/Backing Vocals, Robin Hayes (Guitar) and David Mitchell (Drums).
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Electricity (from New Latin ēlectricus, "amberlike") is a general term for a variety of phenomena resulting from the presence and flow of electric charge. This includes many well-known physical phenomena such as lightning, electromagnetic fields and electric currents,
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Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information.
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A wire is a single, usually cylindrical, elongated strand of drawn metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals . Standard sizes are determined by various wire gauges.
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Telecommunication is the transmission of signals over a distance for the purpose of communication. In modern times, this process typically involves the sending of electromagnetic waves by electronic transmitters, but in earlier times telecommunication may have involved the use of
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Information technology (IT), as defined by the Information Technology Association of America (ITAA), is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware.
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mobile phone or cell phone is a long-range, portable electronic device used for mobile communication. In addition to the standard voice function of a telephone, current mobile phones can support many additional services such as SMS for text messaging, email, packet switching
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Personal digital assistants (PDAs) are handheld computers, but have become much more versatile over the years. PDAs are also known as pocket computers or palmtop computers.
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While the term wireless network may technically be used to refer to any type of network that is wireless, the term is most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a
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Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 medium Earth orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its
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A garage door opener is a motorized device that opens and closes garage doors. Most are controlled by switches on the garage wall, as well as by remote controls carried in the garage owner's cars.
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Editing of this page by unregistered or newly registered users is currently disabled due to vandalism.
If you are prevented from editing this page, and you wish to make a change, please discuss changes on the talk page, request unprotection, log in, or .
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keyboard is a peripheral partially modeled after the typewriter keyboard. Keyboards are designed to input text and characters, as well as to operate a computer. Physically, keyboards are an arrangement of rectangular buttons, or "keys".
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The of this article or section may be compromised by "weasel words".
You can help Wikipedia by removing weasel words. Satellite television is television delivered by way of communications satellites, as compared to conventional terrestrial television and cable television.
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The telephone is a telecommunications device which is used to transmit and receive sound (most commonly speech). Most telephones operate through transmission of electric signals over a complex telephone network which allows almost any phone user to communicate with almost anyone.
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Radio frequency, or RF, is a frequency or rate of oscillation within the range of about 3 Hz and 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves.
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Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light with the longest wavelength.
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laser is a mechanical device that produces coherent radiation. The term "laser" is an acronym: Light Amplification by Stimulated Emission of Radiation.
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Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.
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Microwaves are electromagnetic waves with wavelengths shorter than one meter and longer than one millimeter, or frequencies between 300 megahertz and 300 gigahertz.
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Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light with the longest wavelength.
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remote control is an electronic device used for the remote operation of a machine.

The term remote control can be also referred to as "remote" or "controller" when abbreviated.
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The initials IRDA can refer to various things:
  • In Information Technology and Communications, IrDA refers to Infrared Data Association, a standard for communication between devices (such as computers, PDAs and mobile phones) over short distances using infrared signals.

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Point-to-point telecommunications generally refers to a connection restricted to two endpoints, usually host computers.

Point-to-point is sometimes referred to as P2P, or Pt2Pt, or variations of this. Among other things, P2P also refers to peer-to-peer file sharing networks.
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Point-to-multipoint communication is a term that is used in the telecommunications field which refers to communication which is accomplished via a specific and distinct type of multipoint connection, providing multiple paths from a single location to multiple locations[1]
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Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. The audience may be the general public or a relatively large sub-audience, such as children or young adults.
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A cellular network is a radio network made up of a number of radio cells (or just cells) each served by a fixed transmitter, known as a cell site or base station.
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While the term wireless network may technically be used to refer to any type of network that is wireless, the term is most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a
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For the record label, see .
The term cordless literally means without a cord and is generally used to refer to powered electrical or electronic devices that are able to operate from a portable power source (e.g.
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