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Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor,
optical fiber An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair Hair is a protein filament that grows ...
or other continuous guided
medium Medium may refer to: Science and technology Aviation * Medium bomber, a class of war plane * Tecma Medium, a French hang glider design Communication * Media (communication), tools used to store and deliver information or data * Medium ...
for the transfer. The most common wireless technologies use
radio wave Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (sho ...
s. With radio waves, intended distances can be short, such as a few meters for
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
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 radios,
cellular telephones A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
,
personal digital assistant 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 widespread adoption of highly capable smartphones, in part ...
s (PDAs), and wireless networking. Other examples of applications of radio ''wireless technology'' include GPS units, garage door openers, wireless
computer mouse A computer mouse (plural mice, sometimes mouses) is a hand-held pointing device that detects two-dimensional space, two-dimensional motion relative to a surface. This motion is typically translated into the motion of a pointer (user interface ...
, keyboards and headsets, headphones, radio receivers,
satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna com ...
, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications involve other electromagnetic phenomena, such as light and 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'', until the new word ''radio'' replaced it around 1920. Radio sets in the UK and the English-speaking world that were not portable continued to be referred to as ''wireless sets'' into the 1960s. The term ''wireless'' 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 Internet access via mobile networks. Access to the network can be made through a portable modem, wireless modem, or a tablet/ smartphone (possibly tethered) or other mobile device. The fir ...
,
Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...
and
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
. 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, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that ...
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 and 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 (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and T ...
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, Chichester Bell, Alexander's father-in-law Gardiner Hubba ...
invented the
photophone The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 ...
, 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 communications, or conveyance of information, by armed forces. Military communications span from pre-history to the present. The earliest military communications were delivered ...
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 light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is pr ...
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 (emf) across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Cle ...
were investigated for telegraphy in the late 19th century before practical
radio Radio is the technology of signaling and 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 called a tr ...
systems became available. These included a patented induction system by Thomas Edison allowing a telegraph on a running train to connect with telegraph wires running parallel to the tracks, a William Preece 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, also known as the 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 ...
and earth conductive systems found limited use between trenches during
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...
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 Italian inventor and electrical engineer, known for his creation of a practical radio wave-based wireless telegraph system. This led to Marconi ...
began developing a wireless telegraph system using 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 who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism. The uni ...
, 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). Marconi and
Karl Ferdinand Braun Karl Ferdinand Braun (; 6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of radio and television technology: he shared the ...
were awarded the 1909 Nobel Prize for Physics for their contribution to this form of wireless telegraphy.
Millimetre wave 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, -er, ...
communication was first investigated by Jagadish Chandra Bose during 18941896, when he reached an extremely high frequency of up to 60 GHz in his experiments. He also introduced the use of
semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way ...
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 that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...
ed the
radio Radio is the technology of signaling and 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 called a tr ...
crystal detector A crystal detector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal. It was employed as a detector (dem ...
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, mobile telephony, pagers, wireless computer networks, cellular networks, the wireless Internet, and
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
and handheld computers with wireless connections. The wireless revolution has been driven by advances in
radio frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the up ...
(RF) and microwave engineering, 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 digits. An exampl ...
such as text messaging, images and
streaming media Streaming media is multimedia that is delivered and consumed in a continuous manner from a source, with little or no intermediate storage in network elements. ''Streaming'' refers to the delivery method of content, rather than the content i ...
.


Modes

''Wireless communications'' can be via:


Radio

Radio Radio is the technology of signaling and 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 called a tr ...
and
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
communication carry information by
modulating In music, modulation is the change from one tonality ( tonic, or tonal center) to another. This may or may not be accompanied by a change in key signature (a key change). Modulations articulate or create the structure or form of many pieces, a ...
properties of 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 particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...
to its
antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...
. 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 demodulated to recreate the information sent by the transmitter.


Free-space optical

Free-space optical communication (FSO) is an 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, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that ...
s or
computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...
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 lines such as
optical fiber An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair Hair is a protein filament that grows ...
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 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 ...
s and IrDA ( Infrared Data Association) networking, which is used as an alternative to WiFi networking to allow laptops, PDAs, printers, and digital cameras to exchange data.


Sonic

Sonic, especially ultrasonic 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 (emf) across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Cle ...
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 tags.


Services

Common examples of wireless equipment include: *Infrared and ultrasonic remote control devices *Professional LMR (
Land Mobile Radio A land mobile radio system (LMRS) is a person-to-person voice communication system consisting of two-way radio transceivers (an audio transmitter and receiver in one unit) which can be stationary (base station units), mobile (installed in vehicle ...
) and SMR (
Specialized Mobile Radio Specialized Mobile Radio (SMR) may be an analog or digital trunked two-way radio system, operated by a service in the VHF, 220, UHF, 700, 800 or 900 MHz bands. Some systems with advanced features are referred to as an Enhanced Specialized Mo ...
) typically used by business, industrial and Public Safety entities. *Consumer Two-way radio 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. I ...
, GMRS (General Mobile Radio Service) and Citizens band ("CB") radios. *The Amateur Radio Service (Ham radio). *Consumer and professional Marine VHF radios. * Airband and radio navigation equipment used by aviators and
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airsp ...
*
Cellular telephone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while ...
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 and operated by the United States Space Force. It is one of the global navigation satellite ...
(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 or
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
. * Cordless telephone 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 orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna com ...
: 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 geosynchronous orbit in altitu ...
. Typical services use
direct broadcast satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna comm ...
to provide multiple
television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...
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 frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging fro ...
. The frequencies of the
radio spectrum The radio spectrum is the part of the electromagnetic spectrum with frequencies from 0  Hz to 3,000  GHz (3  THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particul ...
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 of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdicti ...
, Ofcom 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 (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency ...
or the European ETSI. 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 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, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
, 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 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 called a tr ...
signals from these instruments.


Data communications

Wireless data communications allows wireless networking between desktop computers,
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
s, tablet computers, cell phones 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 Mobile may refer to: Places * Mobile, Alabama, a U.S. port city * Mobile County, Alabama * Mobile, Arizona, a small town near Phoenix, U.S. * Mobile, Newfoundland and Labrador Arts, entertainment, and media Music Groups and labels * Mobile ...
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 v ...
. Supporting technologies include: :
Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...
is a wireless
local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a large ...
that enables portable computing devices to connect easily with other devices, peripherals, 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 '' network of networks'' that consists of private, p ...
. Standardized as IEEE 802.11 a, b, g, n, ac, ax,
Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...
has link speeds similar to older standards of wired
Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...
. 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. Speeds have increased as technologies have evolved, from earlier technologies such as GSM, CDMA and GPRS, through 3G, to 4G networks such as W-CDMA, EDGE 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 (telecommunication), signaling data between mobile phones and cell sites. It is developed by 3GP ...
. As of 2018, the proposed next generation is 5G. :Low-power wide-area networks ( LPWAN) bridge the gap between Wi-Fi and Cellular for low bitrate Internet of things (IoT) applications. :
Mobile-satellite communications Mobile-satellite service (MSS, or mobile-satellite radiocommunication service) is – according to Article 1.25 of the International Telecommunication Union's Radio Regulations – "A radiocommunication service * between mobile earth stations an ...
may be used where other wireless connections are unavailable, such as in largely rural areas or remote locations. Satellite communications are especially important for transportation,
aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes airplane, fixed-wing and helicopter, rotary-wing types, morphable wings, wing-less lifting bodies, as well as aerostat, lighter- ...
,
maritime Maritime may refer to: Geography * Maritime Alps, a mountain range in the southwestern part of the Alps * Maritime Region, a region in Togo * Maritime Southeast Asia * The Maritimes, the Canadian provinces of Nova Scotia, New Brunswick, and Pri ...
and
military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
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 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 technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
or Wireless USB, 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: 0G, 1G, 2G, 3G, 4G, 5G, 6G * Cordless telephony: DECT ( Digital Enhanced Cordless Telecommunications) *
Land Mobile Radio A land mobile radio system (LMRS) is a person-to-person voice communication system consisting of two-way radio transceivers (an audio transmitter and receiver in one unit) which can be stationary (base station units), mobile (installed in vehicle ...
or Professional Mobile Radio: TETRA, P25, OpenSky, EDACS, DMR, dPMR * List of emerging technologies *
Radio station Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio ...
in accordance with
ITU The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union ...
RR (article 1.61) * Radiocommunication service in accordance with ITU RR (article 1.19) * Radio communication system *Short-range point-to-point communication:
Wireless microphone A wireless microphone, or cordless microphone, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated. Also known as a radio microphone, it has a small, battery ...
s,
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 ...
s,
IrDA The Infrared Data Association (IrDA) is an industry-driven interest group that was founded in 1994 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications, and the name "IrDA" also ...
, RFID (Radio Frequency Identification),
TransferJet TransferJet is a close proximity wireless transfer technology initially proposed by Sony and demonstrated publicly in early 2008. By touching (or bringing very close together) two electronic devices, TransferJet allows high speed exchange of data. ...
, Wireless USB, DSRC (Dedicated Short Range Communications), EnOcean, Near Field Communication * Wireless sensor networks:
ZigBee Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and oth ...
, EnOcean;
Personal area network A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. A PAN provides data transmission among devices such as computers, smartphones, tablets and personal digital ...
s,
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
,
TransferJet TransferJet is a close proximity wireless transfer technology initially proposed by Sony and demonstrated publicly in early 2008. By touching (or bringing very close together) two electronic devices, TransferJet allows high speed exchange of data. ...
, Ultra-wideband (UWB from WiMedia Alliance). * Wireless networks: Wireless LAN (WLAN), ( IEEE 802.11 branded as
Wi-Fi Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...
and HiperLAN), Wireless Metropolitan Area Networks (WMAN) and ( LMDS,
WiMAX Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX ...
, and HiperMAN)


See also

* Comparison of wireless data standards * Digital radio * Hotspot (Wi-Fi) * Li-Fi * MiFi *
Mobile (disambiguation) Mobile may refer to: Places * Mobile, Alabama, a U.S. port city * Mobile County, Alabama * Mobile, Arizona, a small town near Phoenix, U.S. * Mobile, Newfoundland and Labrador Arts, entertainment, and media Music Groups and labels * Mobile ...
* Radio antenna *
Radio resource management Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, ...
(RRM) *Timeline of radio *Tuner (radio) *Wireless access point *Wireless security *Wireless Wide Area Network (True wireless) *ISO 15118 (Vehicle to Grid) *WSSUS model


References


Further reading

* * * * * * * * *


External links

* *
Bibliography - History of wireless and radio broadcasting


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