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Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an
electrical conductor In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force ...
as a medium by which to perform the transfer. The most common wireless technologies use
radio wave Radio waves are a type of electromagnetic radiation In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies ma ...
s. With radio waves, intended distances can be short, such as a few meters for
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including
two-way radio A two-way radio is a that can both transmit and receive s (a ), unlike a receiver which only receives content. It is an audio (sound) , a and in one unit, used for bidirectional person-to-person voice communication with other users with ...
s,
cellular telephones Cellular may refer to: *Cellular automaton, a model in discrete mathematics *Cell biology, the evaluation of cells work and more *Cellular (film), ''Cellular'' (film), a 2004 movie *Cellular frequencies, assigned to networks operating in cellular ...

cellular telephones
,
personal digital assistant#REDIRECT Personal digital assistant The Palm TX A personal digital assistant (PDA), also known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs have been mostly displaced by the widesprea ...
s (PDAs), and
wireless network A wireless network is a computer network A computer network is a set of s sharing resources located on or provided by . The computers use common s over to communicate with each other. These interconnections are made up of technologies, ...

wireless network
ing. Other examples of applications of radio ''wireless technology'' include
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...
units,
garage door opener A garage door opener is a motorized device that opens and closes a garage door A garage door is a large door on a Garage (house), garage that opens either manually or by an electric motor (a garage door opener). Garage doors are frequently la ...

garage door opener
s, wireless
computer mouse A computer mouse (plural mice, sometimes mouses) is a hand-held pointing device A pointing device is a human interface device A human interface device or HID is a type of computer device usually used by humans that takes input fro ...
,
keyboards Keyboard may refer to: Text input * Keyboard, part of a typewriter A typewriter is a machine, mechanical or electromechanical machine for typing characters similar to those produced by a printer's movable type. Typically, a typewriter has an arr ...
and headsets,
headphone Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound In physics Physics (from grc ...

headphone
s,
radio receiver radio in the 1940s. During the golden age of radio, 1925–1955, families gathered to listen to the home radio receiver in the evening In radio, radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is ...

radio receiver
s,
satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals v ...
,
broadcast television Broadcast Broadcasting is the distributionDistribution may refer to: Mathematics *Distribution (mathematics) Distributions, also known as Schwartz distributions or generalized functions, are objects that generalize the classical notio ...
and
cordless telephone A cordless telephone or portable telephone is a telephone A telephone is a telecommunications Appliance (disambiguation), device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A ...
s. Somewhat less common methods of achieving wireless communications include the use of other
electromagnetic Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electric charge, electrically charged particles. The electromagnetic force is carried by electromagneti ...

electromagnetic
wireless technologies, such as light, magnetic, or electric fields or the use of sound. The term ''wireless'' has been used twice in communications history, with slightly different meaning. It was initially used from about 1890 for the first radio transmitting and receiving technology, as in ''
wireless telegraphy Wireless telegraphy or radiotelegraphy is transmission of telegraph Telegraphy is the long-distance transmission of textual messages where the sender uses a semaphore system, known to the recipient, rather than a physical exchange of an ...
'', until the new word ''radio'' replaced it around 1920. Radios in the UK that were not portable continued to be referred to as ''wireless sets'' into the 1960s. The term was revived in the 1980s and 1990s mainly to distinguish digital devices that communicate without wires, such as the examples listed in the previous paragraph, from those that require wires or cables. This became its primary usage in the 2000s, due to the advent of technologies such as
mobile broadband Mobile broadband is the marketing term for wireless Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an electrical conductor as a medium by which to ...
,
Wi-Fi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...

Wi-Fi
and
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
. Wireless operations permit services, such as mobile and interplanetary communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the
telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, Optical system, optical, or other Electromagnetism, electromagnetic systems. It has its origin in the desire of humans for communication ov ...
industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls, etc.) which use some form of energy (e.g.
radio waves Radio waves are a type of electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space a ...

radio waves
, acoustic energy,) to transfer information without the use of wires. Information is transferred in this manner over both short and long distances.


History


Photophone

The first wireless telephone conversation occurred in 1880, when
Alexander Graham Bell Alexander Graham Bell (; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist, and engineer who is credited with inventing and patenting the first practical telephone. He also co-founded the (AT&T) in 1885. , grandf ...

Alexander Graham Bell
and
Charles Sumner Tainter Charles Sumner Tainter (April 25, 1854 – April 20, 1940) was an American scientific instrument maker, engineer and inventor, best known for his collaborations with Alexander Graham Bell Alexander Graham Bell (; born Alexander Bell, March 3, ...

Charles Sumner Tainter
invented the
photophone A diagram from one of Bell's 1880 papers The photophone is a telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, Optical system, optical, or other Electromagnetism, elect ...

photophone
, a telephone that sent audio over a beam of light. The photophone required sunlight to operate, and a clear line of sight between transmitter and receiver. These factors greatly decreased the viability of the photophone in any practical use. It would be several decades before the photophone's principles found their first practical applications in
military communications Military communications or military signals involve all aspects of communication Communication (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin wa ...
and later in
fiber-optic communication Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared Infrared (IR), sometimes called infrared light, is (EMR) with s longer than those of . It is therefore invisible to ...
s.


Electric wireless technology


Early wireless

A number of wireless electrical signaling schemes including sending electric currents through water and the ground using electrostatic and
electromagnetic induction Electromagnetic or magnetic induction is the production of an electromotive force In electromagnetism Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs b ...

electromagnetic induction
were investigated for telegraphy in the late 19th century before practical
radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device ...

radio
systems became available. These included a patented induction system by
Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation Electricity generation is the process of generating electric power from s ...

Thomas Edison
allowing a telegraph on a running train to connect with telegraph wires running parallel to the tracks, a
William Preece Sir William Henry Preece (15 February 1834 – 6 November 1913) was a Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language of the Indo-European language family, indigen ...
induction telegraph system for sending messages across bodies of water, and several operational and proposed telegraphy and voice earth conduction systems. The Edison system was used by stranded trains during the
Great Blizzard of 1888 The Great Blizzard of 1888, Great Blizzard of '88, or the Great White Hurricane (March 11–14, 1888) was one of the most severe recorded blizzards in American history. The storm paralyzed the East Coast from the Chesapeake Bay The Chesapeake ...
and earth conductive systems found limited use between trenches during
World War I World War I, often abbreviated as WWI or WW1, also known as the First World War or the Great War, was a global war A world war is "a war engaged in by all or most of the principal nations of the world". The term is usually reserved for ...

World War I
but these systems were never successful economically.


Radio waves

In 1894,
Guglielmo Marconi Guglielmo Giovanni Maria Marconi, 1st Marquis of Marconi (; 25 April 187420 July 1937) was an inventor and , known for his creation of a practical -based system. This led to Marconi being credited as the , and he shared the 1909 with "in ...

Guglielmo Marconi
began developing a wireless telegraph system using
radio waves Radio waves are a type of electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space a ...

radio waves
, which had been known about since proof of their existence in 1888 by
Heinrich Hertz Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist A physicist is a scientist A scientist is a person who conducts scientific research The scientific method is an Empirical evidence, empi ...

Heinrich Hertz
, but discounted as a communication format since they seemed, at the time, to be a short range phenomenon. Marconi soon developed a system that was transmitting signals way beyond distances anyone could have predicted (due in part to the signals bouncing off the then unknown
ionosphere The ionosphere () is the ionized part of Earth's upper atmosphere, from about to altitude, a region that includes the thermosphere The thermosphere is the layer in the directly above the and below the . Within this layer of the atmosphere, ...
). Marconi and
Karl Ferdinand Braun 24 September 1900: Bargman, Braun and telegraphist at wireless station Heligoland Karl Ferdinand Braun (6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist A physicist is a scientist A scientist is a pe ...
were awarded the 1909
Nobel Prize for Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...
for their contribution to this form of wireless telegraphy.
Millimetre wave The millimetre ( international spelling; SI unit symbol mm) or millimeter ( American spelling) is a unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' ...
communication was first investigated by
Jagadish Chandra Bose Sir Jagadish Chandra Bose (;, ; 30 November 1858 – 23 November 1937) was a biologist A biologist is a professional who has specialized knowledge in the field of biology, understanding the underlying mechanisms that govern the functioni ...

Jagadish Chandra Bose
during 18941896, when he reached an
extremely high frequency Extremely high frequency (EHF) is the International Telecommunication Union File:ITU monument, Bern.jpg, 260px, ITU Monument, Bern The International Telecommunication Union is a list of specialized agencies of the United Nations, specializ ...
of up to 60
GHz The hertz (symbol: Hz) is the unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatric ...
in his experiments. He also introduced the use of
semiconductor A semiconductor material has an electrical conductivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric curre ...
junctions to detect radio waves, reprinted in Igor Grigorov, Ed.,
Antentop
', Vol. 2, No.3, pp. 87–96.
when he
patent A patent is a type of intellectual property Intellectual property (IP) is a category of property Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depe ...

patent
ed the
radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device ...

radio
crystal detector A crystal detector is an electronic component An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial ...
in 1901.


Wireless revolution

Power_MOSFETs,_which_are_used_in_RF_power_amplifiers_to_boost_radio_frequency.html" ;"title="RF_power_amplifier.html" ;"title="Power MOSFETs, which are used in RF power amplifier">Power MOSFETs, which are used in RF power amplifiers to boost radio frequency">RF_power_amplifier.html" ;"title="Power MOSFETs, which are used in RF power amplifier">Power MOSFETs, which are used in RF power amplifiers to boost radio frequency (RF) signals in long-distance wireless networks. The wireless revolution began in the 1990s, with the advent of digital wireless networks leading to a social revolution, and a paradigm shift from wired to wireless technology, including the proliferation of commercial wireless technologies such as
cell phones A mobile phone, cellular phone, cell phone, cellphone, handphone, or hand phone, sometimes shortened to simply mobile, cell or just phone, is a portable telephone that can make and receive telephone call, calls over a radio frequency link wh ...

cell phones
,
mobile telephony Mobile telephony is the provision of to which may rather than stay in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur. Mobile phones connect to a terrestr ...
,
pagers A pager (also known as a beeper, bleeper or pocket bell) is a wireless telecommunications device that receives and displays alphanumeric or voice messages. One-way pagers can only receive messages, while response pagers and two-way pagers can ...
, wireless
computer networks A computer network is a group of computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as Compute ...
,
cellular network A cellular network or mobile network is a communication network A telecommunications network is a group of nodes In general, a node is a localized swelling (a "knot") or a point of intersection (a Vertex (graph theory), vertex). Node may re ...
s, the
wireless Internet Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an electrical conductor In physics Physics (from grc, φυσική (ἐπιστήμη), ph ...
, and
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer File:Crystal Project computer.png, upright=0.9, An artist's depiction of a 2000s-era desktop-style personal computer, which includes a metal case with ...

laptop
and handheld computers with wireless connections. The wireless revolution has been driven by advances in
radio frequency Radio frequency (RF) is the oscillation Oscillation is the repetitive variation, typically in time Time is the indefinite continued sequence, progress of existence and event (philosophy), events that occur in an apparently irreversible p ...
(RF) and
microwave engineering Microwave engineering pertains to the study and design of microwave Microwave is a form of electromagnetic radiation In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, fr ...
, and the transition from analog to digital RF technology, which enabled a substantial increase in voice traffic along with the delivery of
digital data Digital data, in information theory and information systems, is information represented as a string of discrete symbols each of which can take on one of only a finite number of values from some alphabet, such as letters or digit (unit), digits. A ...
such as
text messaging Text messaging, or texting, is the act of composing and sending electronic messages, typically consisting of alphabetic and numeric characters, between two or more users of mobile device A mobile device (or handheld computer) is a computer ...
,
images An image (from la, imago) is an artifact that depicts visual perception, such as a photograph or other Two-dimensional space, two-dimensional picture, that resembles a subject—usually a physical physical body, object—and thus provides ...
and
streaming media Streaming media is multimedia Multimedia is a form of communication that combines different such as , , , , or into a single interactive presentation, in contrast to traditional mass media which ...
.


Modes

''Wireless communications'' can be via:


Radio

Radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device ...

Radio
and
microwave Microwave is a form of electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space a ...

microwave
communication carry information by
modulating In music Music is the of arranging s in time through the of melody, harmony, rhythm, and timbre. It is one of the aspects of all human societies. General include common elements such as (which governs and ), (and its associated con ...

modulating
properties of
electromagnetic waves In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through ...

electromagnetic waves
transmitted through space. Specifically, the transmitter generates artificial electromagnetic waves by applying time-varying
electric currents An electric current is a stream of charged particle In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, ...
to its
antenna Antenna (pl. antennas or antennae) may refer to: Science and engineering * Antenna (radio) In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal con ...
. The waves travel away from the antenna until they eventually reach the antenna of a receiver, which induces an electrical current in the receiving antenna. This current can be detected and to recreate the information sent by the transmitter.


Free-space optical

Free-space optical communication (FSO) is an
optical communication Optical communication, also known as optical telecommunication, is communication Communication (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was ...

optical communication
technology that uses light propagating in free space to transmit wirelessly data for
telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Gr ...
s or
computer network A computer network is a set of computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operati ...
ing. "Free space" means the light beams travel through the open air or outer space. This contrasts with other communication technologies that use light beams traveling through
transmission line In electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics The field of electronics is a branch o ...

transmission line
s such as
optical fiber An optical fiber (or fibre in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codificati ...

optical fiber
or dielectric "light pipes". The technology is useful where physical connections are impractical due to high costs or other considerations. For example, free space optical links are used in cities between office buildings which are not wired for networking, where the cost of running cable through the building and under the street would be prohibitive. Another widely used example is
consumer IR Consumer IR, consumer infrared, or CIR is a class of devices employing the infrared Infrared (IR), sometimes called infrared light, is (EMR) with s longer than those of . It is therefore invisible to the human eye. IR is generally understoo ...
devices such as
remote control In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as ...

remote control
s and IrDA (
Infrared Data Association Infrared via USB The Infrared Data Association (IrDA) is an industry-driven interest group that was founded in 1993 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications, and t ...
) networking, which is used as an alternative to
WiFi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...
networking to allow laptops, PDAs, printers, and digital cameras to exchange data.


Sonic

Sonic, especially short range communication involves the transmission and reception of sound.


Electromagnetic induction

Electromagnetic induction Electromagnetic or magnetic induction is the production of an electromotive force In electromagnetism Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs b ...

Electromagnetic induction
only allows short-range communication and power transmission. It has been used in biomedical situations such as pacemakers, as well as for short-range
RFID Radio-frequency identification (RFID) uses electromagnetic field An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field Field may refer to: Expanses of open ground * Field (agriculture), an area of land used fo ...
tags.


Services

Common examples of wireless equipment include: *Infrared and ultrasonic remote control devices *Professional LMR ( Land Mobile Radio) and SMR (Specialized
Mobile Radio Mobile radio or mobiles refer to wireless communications systems and devices which are based on radio frequencies(using commonly UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megaher ...
) typically used by business, industrial and Public Safety entities. *Consumer
Two-way radio A two-way radio is a radio that can both transmit and receive radio waves (a transceiver), unlike a radio broadcasting, broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and radio receiver, re ...
including FRS
Family Radio Service The Family Radio Service (FRS) is an improved walkie-talkie radio system authorized in the United States since 1996. This personal radio service uses channelized frequencies around 462 and 467 MHz in the ultra high frequency (UHF) band. It ...
, GMRS (General Mobile Radio Service) and Citizens band ("CB") radios. *The
Amateur Radio Amateur radio, also known as ham radio, is the use of radio frequency Radio frequency (RF) is the oscillation Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibri ...
Service (Ham radio). *Consumer and professional Marine VHF radios. *
Airband Airband or aircraft band is the name for a group of in the allocated to radio communication in civil , sometimes also referred to as ''VHF'', or phonetically as ''"Victor"''. Different sections of the band are used for s and . In most countr ...
and
radio navigation Radio navigation or radionavigation is the application of radio Radio is the technology of signaling and communicating Communication (from Latin ''communicare'', meaning "to share") is the act of developing Semantics, meaning among Sub ...
equipment used by
aviator An aircraft pilot or aviator is a person who controls the flight of an aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using eit ...
s and
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controller Air traffic control specialists, abbreviated ATCS, are personnel responsible for the safe, orderly, and expeditious flow of air traffic in the global ...

air traffic control
*
Cellular telephone A mobile phone, cellular phone, cell phone, cellphone, handphone, or hand phone, sometimes shortened to simply mobile, cell or just phone, is a portable telephone A telephone is a telecommunications device that permits two or more use ...
s and pagers: provide connectivity for portable and mobile applications, both personal and business. *
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government or U.S. governme ...
(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; wireless headphones, keyboards, and printers can also be linked to a computer via wireless using technology such as
Wireless USB Wireless USB was a short-range, high-bandwidth wireless Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an electrical conductor as a medium by which ...
or
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
. *
Cordless telephone A cordless telephone or portable telephone is a telephone A telephone is a telecommunications Appliance (disambiguation), device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A ...
sets: these are limited-range devices, not to be confused with cell phones. *
Satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals v ...
: Is broadcast from satellites in
geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular Circular may refer to: * The sha ...

geostationary orbit
. Typical services use
direct broadcast satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals v ...
to provide multiple
television Television, sometimes shortened to TV or telly, is a telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Gre ...

television
channels to viewers.


Electromagnetic spectrum

AM and FM radios and other electronic devices make use of the
electromagnetic spectrum The electromagnetic spectrum is the range of frequency, frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energy, photon energies. The electromagnetic spectrum covers electromagnetic waves with f ...

electromagnetic spectrum
. The frequencies of the
radio spectrum The radio spectrum is the part of the electromagnetic spectrum with Frequency, frequencies from 3 hertz, Hz to 300 Hertz, GHz. Electromagnetic waves in this frequency range, called ''radio waves'', are widely used in modern technology, ...
that are available for use for communication are treated as a public resource and are regulated by organizations such as the American
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency A regulatory agency or regulatory authority, is a Public benefit corporation Public-benefit corporation is a term that has different meanings in different jurisdictions. I ...
,
Ofcom The Office of Communications ( cy, Y Swyddfa Gyfathrebiadau), commonly known as Ofcom, is the government-approved regulatory and competition authority for the broadcasting, telecommunication Telecommunication is the transmission of inform ...
in the United Kingdom, the international
ITU-R The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union 260px, ITU Monument, Bern The International Telecommunication Union is a specialized agency of the Unit ...
or the European
ETSI ETSI (European Telecommunications Standards Institute) is an independent, not-for-profit, standardization Standardization or standardisation is the process of implementing and developing technical standard A technical standard is an establis ...
. Their regulations determine which frequency ranges can be used for what purpose and by whom. In the absence of such control or alternative arrangements such as a privatized electromagnetic spectrum, chaos might result if, for example, airlines did not have specific frequencies to work under and an
amateur radio Amateur radio, also known as ham radio, is the use of radio frequency Radio frequency (RF) is the oscillation Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibri ...
operator was interfering with a pilot's ability to land an aircraft. Wireless communication spans the spectrum from 9 kHz to 300 GHz.


Applications


Mobile telephones

One of the best-known examples of wireless technology is the
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, or hand phone, sometimes shortened to simply mobile, cell or just phone, is a portable telephone A telephone is a telecommunication Telecommunication is the tra ...

mobile phone
, also known as a cellular phone, with more than 6.6 billion mobile cellular subscriptions worldwide as of the end of 2010. These wireless phones use radio waves from signal-transmission towers to enable their users to make phone calls from many locations worldwide. They can be used within range of the mobile telephone site used to house the equipment required to transmit and receive the
radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device ...

radio
signals from these instruments.


Data communications

Wireless data communications allows
wireless networking A wireless network is a computer network A computer network is a set of computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern ...

wireless networking
between
desktop computer A desktop computer is a personal computer A personal computer (PC) is a multi-purpose computer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, ...
s,
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer File:Crystal Project computer.png, upright=0.9, An artist's depiction of a 2000s-era desktop-style personal computer, which includes a metal case with ...

laptop
s,
tablet computer A tablet computer, commonly shortened to tablet, is a mobile device A mobile device (or handheld computer) is a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations aut ...
s,
cell phone A mobile phone, cellular phone, cell phone, cellphone, handphone, or hand phone, sometimes shortened to simply mobile, cell or just phone, is a portable telephone A telephone is a telecommunication Telecommunication is the tra ...

cell phone
s and other related devices. The various available technologies differ in local availability, coverage range and performance, and in some circumstances users employ multiple connection types and switch between them using connection manager software or a mobile VPN to handle the multiple connections as a secure, single
virtual network In computing, network virtualization is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform vi ...
. Supporting technologies include: :
Wi-Fi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...

Wi-Fi
is a wireless
local area network A local area network (LAN) is a computer network A computer network is a set of s sharing resources located on or provided by . The computers use common s over to communicate with each other. These interconnections are made up of te ...
that enables portable computing devices to connect easily with other devices,
peripheral A peripheral or peripheral device is an auxiliary device used to put information into and get information out of the computer. The term peripheral device refers to all hardware components that are attached to a computer and are controlled by the co ...
s, and the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consist ...

Internet
. Standardized as
IEEE 802.11 IEEE 802.11 is part of the IEEE 802 IEEE 802 is a family of Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a professional association for electronic engineering and electri ...
a, b, g, n, ac, ax,
Wi-Fi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...

Wi-Fi
has link speeds similar to older standards of wired
Ethernet Ethernet () is a family of wired computer network A computer network is a set of s sharing resources located on or provided by . The computers use common s over to communicate with each other. These interconnections are made up of te ...

Ethernet
. Wi-Fi has become the de facto standard for access in private homes, within offices, and at public hotspots. Some businesses charge customers a monthly fee for service, while others have begun offering it free in an effort to increase the sales of their goods. :Cellular data service offers coverage within a range of 10-15 miles from the nearest
cell site A cell site, cell tower, or cellular base station is a cellular-enabled mobile device A mobile device (or handheld computer) is a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical ...
. Speeds have increased as technologies have evolved, from earlier technologies such as
GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * GSM London, a higher education provider * Guildhall School of Music and Drama The Guildhall School of Music and Drama i ...

GSM
,
CDMA Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of channel access method, multiple access, where several transmitters can send information simultaneously over ...
and
GPRS General Packet Radio Service (GPRS) is a packet oriented Statistical multiplexing is a type of communication link sharing, very similar to dynamic bandwidth allocation (DBA). In statistical multiplexing, a communication channel is divided into ...
, through , to 4G networks such as
W-CDMA The Universal Mobile Telecommunications System (UMTS) is a 3G, third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the In ...
,
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing Edge computing is a distributed computing paradigm that brings computation and data storage closer to the sources of data. This is expected to improve response times and save bandw ...
or
CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling In signal processing Signal processing is an electrical engineering subfield that focu ...
. As of 2018, the proposed next generation is 5G. :Low-power wide-area networks (
LPWAN A low-power wide-area network (LPWAN) or low-power wide-area (LPWA) network or low-power network (LPN) is a type of wireless telecommunication wide area network designed to allow long-range communications at a low bit rate among Internet of things ...
) bridge the gap between Wi-Fi and Cellular for low bitrate
Internet of things The Internet of things (IoT) describes the network of physical objects—"things" or objects—that are embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices and systems over ...

Internet of things
(IoT) applications. : Mobile-satellite communications may be used where other wireless connections are unavailable, such as in largely rural areas or remote locations. Communications satellite, Satellite communications are especially important for transportation, aviation, sea, maritime and military use. :Wireless sensor networks are responsible for sensing noise, interference, and activity in data collection networks. This allows us to detect relevant quantities, monitor and collect data, formulate clear user displays, and to perform decision-making functions Wireless data communications are used to span a distance beyond the capabilities of typical cabling in point-to-point (telecommunications), point-to-point communication and point-to-multipoint communication, 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.


Peripherals

Peripheral devices in computing can also be connected wirelessly, as part of a Wi-Fi network or directly via an optical or radio-frequency (RF) peripheral interface. Originally these units used bulky, highly local transceivers to mediate between a computer and a keyboard and mouse; however, more recent generations have used smaller, higher-performance devices. Radio-frequency interfaces, such as
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
or
Wireless USB Wireless USB was a short-range, high-bandwidth wireless Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an electrical conductor as a medium by which ...
, provide greater ranges of efficient use, usually up to 10 feet, but distance, physical obstacles, competing signals, and even human bodies can all degrade the signal quality. Concerns about the security of wireless keyboards arose at the end of 2007, when it was revealed that Microsoft's implementation of encryption in some of its 27 MHz models was highly insecure.


Energy transfer

Wireless energy transfer is a process whereby electrical energy is transmitted from a power source to an electrical load that does not have a built-in power source, without the use of interconnecting wires. There are two different fundamental methods for wireless energy transfer. Energy can be transferred using either far-field methods that involve beaming power/lasers, radio or microwave transmissions or near-field using electromagnetic induction. Wireless energy transfer may be combined with wireless information transmission in what is known as Wireless Powered Communication. In 2015, researchers at the University of Washington demonstrated far-field energy transfer using Wi-Fi signals to power cameras.


Medical technologies

New wireless technologies, such as mobile body area networks (MBAN), have the capability to monitor blood pressure, heart rate, oxygen level and body temperature. The MBAN works by sending low powered wireless signals to receivers that feed into nursing stations or monitoring sites. This technology helps with the intentional and unintentional risk of infection or disconnection that arise from wired connections.


Categories of implementations, devices and standards

*Cellular networks: Mobile radio telephone, 0G, 1G, 2G, , 4G, Beyond 3G (4G), Future wireless *Cordless telephone, Cordless telephony: DECT (Digital Enhanced Cordless Telecommunications) *Land Mobile Radio System, Land Mobile Radio or Professional Mobile Radio: Terrestrial Trunked Radio, TETRA, Project 25, P25, OpenSky, EDACS, Digital Mobile Radio, DMR, dPMR *List of emerging technologies *Radio station in accordance with International Telecommunication Union, ITU ITU Radio Regulations, RR (article 1.61) *Radiocommunication service in accordance with ITU RR (article 1.19) *Radio communication system *Short-range point-to-point communication: Wireless microphones, Remote controls, Infrared Data Association, IrDA, Radio-frequency identification, RFID (Radio Frequency Identification), TransferJet,
Wireless USB Wireless USB was a short-range, high-bandwidth wireless Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points that do not use an electrical conductor as a medium by which ...
, Dedicated short-range communications, DSRC (Dedicated Short Range Communications), EnOcean, Near Field Communication *Wireless sensor networks: ZigBee, EnOcean; Personal area networks,
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
, TransferJet, Ultra-wideband (UWB from WiMedia Alliance). *Wireless networks: Wireless LAN (WLAN), (
IEEE 802.11 IEEE 802.11 is part of the IEEE 802 IEEE 802 is a family of Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a professional association for electronic engineering and electri ...
branded as
Wi-Fi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...

Wi-Fi
and HiperLAN), Wireless Metropolitan Area Networks (WMAN) and (Local Multipoint Distribution Service, LMDS, WiMAX, and HiperMAN)


See also

*Comparison of wireless data standards *Digital radio *Hotspot (Wi-Fi) *Li-Fi *MiFi *Mobile (disambiguation) *Radio antenna *Radio resource management (RRM) *Timeline of radio *Tuner (radio) *Wireless access point *Wireless security *Wireless Wide Area Network (True wireless) *ISO 15118 (Vehicle to Grid)


References


Further reading

* * * * * * * * *


External links

* *
Bibliography - History of wireless and radio broadcasting


{{Authority control Wireless, Wireless networking, History of radio Television terminology