Jump to content

Wireless

From Wikipedia, the free encyclopedia
(Redirected from Wireless device)

"Over the air broadcasting" redirects here. For the technology over the air television, see Terrestrial television.
A handheld on-board communication station of the maritime mobile service
Part of a series on
Antennas
Common types
Components
Systems
Safety and regulation
Radiation sources / regions
Characteristics
Techniques

Wireless communication (or just wireless, when the context allows) is the transfer of information (telecommunication) between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most common wireless technologies use radio waves. With radio waves, intended distances can be short, such as a few meters for 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 radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, 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 meanings. 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.[1][2] 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, Wi-Fi, and 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 industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls, etc.) that use some form of energy (e.g. radio waves and acoustic energy) to transfer information without the use of wires.[3][4][5] Information is transferred in this manner over both short and long distances.

History

[edit]
See also: History of telecommunication

Photophone

[edit]
Main article: Photophone
Bell and Tainter's photophone, of 1880.

The first wireless telephone conversation occurred in 1880 when Alexander Graham Bell and Charles Sumner Tainter invented the photophone, the telephone that sent audio over a beam of light. The photophone required sunlight to operate, and a clear line of sight between the transmitter and receiver, which greatly decreased the viability of the photophone in any practical use.[6] It would be several decades before the photophone's principles found their first practical applications in military communications and later in fiber-optic communications.

Electric wireless technology

[edit]

Early wireless

[edit]
Main article: Wireless telegraphy

A number of wireless electrical signaling schemes including sending electric currents through water and the ground using electrostatic and electromagnetic induction were investigated for telegraphy in the late 19th century before practical radio 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 and earth conductive systems found limited use between trenches during World War I but these systems were never successful economically.

Radio waves

[edit]
Main article: History of radio
Marconi transmitting the first radio signal across the Atlantic.

In 1894, Guglielmo 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, but discounted as a communication format since they seemed, at the time, to be a short-range phenomenon.[7] 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 were awarded the 1909 Nobel Prize for Physics for their contribution to this form of wireless telegraphy.

Millimetre wave communication was first investigated by Jagadish Chandra Bose during 1894–1896, when he reached an extremely high frequency of up to 60 GHz in his experiments.[8] He also introduced the use of semiconductor junctions to detect radio waves,[9] when he patented the radio crystal detector in 1901.[10][11]

Wireless revolution

[edit]
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,[12][13][14] with the advent of digital wireless networks leading to a social revolution, and a paradigm shift from wired to wireless technology,[15] including the proliferation of commercial wireless technologies such as cell phones, mobile telephony, pagers, wireless computer networks,[12] cellular networks, the wireless Internet, and laptop and handheld computers with wireless connections.[16] The wireless revolution has been driven by advances in radio frequency (RF), microelectronics, and microwave engineering,[12] and the transition from analog to digital RF technology,[15][16] which enabled a substantial increase in voice traffic along with the delivery of digital data such as text messaging, images and streaming media.[15]

Modes

[edit]

Wireless communications can be via:

Radio

[edit]
Main articles: Radio communication and Radio communication service
Further information: Microwave transmission

Radio and microwave communication carry information by modulating properties of electromagnetic waves transmitted through space. Specifically, the transmitter generates artificial electromagnetic waves by applying time-varying electric currents to its antenna. The waves travel away from the antenna until they eventually reach the antenna of a receiver, which induces an electric current in the receiving antenna. This current can be detected and demodulated to recreate the information sent by the transmitter.

Free-space optical

[edit]
Main article: Free-space optical communication
An 8-beam free space optics laser link, rated for 1 Gbit/s at a distance of approximately 2 km. The receptor is the large disc in the middle, and the transmitters are the smaller ones. To the top and right corner is a monocular for assisting the alignment of the two heads.

Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to transmit wireless data for telecommunications or computer networking. "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 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 that 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 controls 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

[edit]

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

Electromagnetic induction

[edit]

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 tags.

Services

[edit]

Common examples of wireless equipment include:[17]

Electromagnetic spectrum

[edit]
See also: Spectrum management

AM and FM radios and other electronic devices make use of the electromagnetic spectrum. The frequencies of the radio spectrum 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, Ofcom in the United Kingdom, the international ITU-R 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.[citation needed]

Applications

[edit]

Mobile telephones

[edit]

One of the best-known examples of wireless technology is the mobile phone, also known as a cellular phone, with more than 6.6 billion mobile cellular subscriptions worldwide as of the end of 2010.[19] 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 the range of the mobile telephone site used to house the equipment required to transmit and receive the radio signals from these instruments.[20]

Data communications

[edit]
"Wireless Internet" redirects here. For all wireless Internet access, see Wireless broadband. For mobile wireless Internet, see Mobile broadband.
See also: Radio data communication

Wireless data communications allow wireless networking between desktop computers, laptops, tablet computers, cell phones, and other related devices. The various available technologies differ in local availability, coverage range, and performance,[21] and in some circumstances, users employ multiple connection types and switch between them using connection manager software[22][23] or a mobile VPN to handle the multiple connections as a secure, single virtual network.[24] Supporting technologies include:

Wi-Fi is a wireless local area network that enables portable computing devices to connect easily with other devices, peripherals, and the Internet.[citation needed] Standardized as IEEE 802.11 a, b, g, n, ac, ax, Wi-Fi has link speeds similar to older standards of wired Ethernet. Wi-Fi has become the de facto standard for access in private homes, within offices, and at public hotspots.[25] 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.[26]
Cellular data service offers coverage within a range of 10-15 miles from the nearest cell site.[21] 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.[27][28] 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 may be used where other wireless connections are unavailable, such as in largely rural areas[29] or remote locations.[21] Satellite communications are especially important for transportation, aviation, maritime and military use.[30]
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[31]

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

[edit]

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 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.[32] 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 were highly insecure.[33]

Energy transfer

[edit]
Main article: Wireless 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.[34] Wireless energy transfer may be combined with wireless information transmission in what is known as Wireless Powered Communication.[35] In 2015, researchers at the University of Washington demonstrated far-field energy transfer using Wi-Fi signals to power cameras.[36]

Medical technologies

[edit]

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.[37]

Categories of implementations, devices, and standards

[edit]

See also

[edit]

References

[edit]
  1. ^ U.S. Army (1944). Technical Manual. US War Department. Retrieved 13 August 2022. In definitions given in the index, p. 162, the term "radio set" is listed as synonymous with the term "wireless set"
  2. ^ Paulu, Burton (1956). British Broadcasting: Radio and Television in the United Kingdom. U of Minnesota Press. ISBN 9781452909547. Retrieved 13 August 2022. (p.396) In a public opinion poll in Sweden in 1942, 31.4 percent answered 'Yes' to the question "Do you usually listen to the foreign news on the wireless?'
  3. ^ "ATIS Telecom Glossary 2007". atis.org. Archived from the original on 2 March 2008. Retrieved 16 March 2008.
  4. ^ Franconi, Nicholas G.; Bunger, Andrew P.; Sejdić, Ervin; Mickle, Marlin H. (24 October 2014). "Wireless Communication in Oil and Gas Wells". Energy Technology. 2 (12): 996–1005. doi:10.1002/ente.201402067. ISSN 2194-4288. S2CID 111149917.
  5. ^ Biswas, S.; Tatchikou, R.; Dion, F. (January 2006). "Vehicle-to-vehicle wireless communication protocols for enhancing highway traffic safety". IEEE Communications Magazine. 44 (1): 74–82. doi:10.1109/mcom.2006.1580935. ISSN 0163-6804. S2CID 6076106.
  6. ^ Amédée Guillemin (1891). Electricity and Magnetism. Macmillan and Company. p. 31. Retrieved 17 April 2021.
  7. ^ Icons of Invention: The Makers of the Modern World from Gutenberg to Gates. ABC-CLIO. 2009. p. 162. ISBN 978-0-313-34743-6.
  8. ^ "Milestones: First Millimeter-wave Communication Experiments by J.C. Bose, 1894-96". List of IEEE milestones. Institute of Electrical and Electronics Engineers. Retrieved 1 October 2019.
  9. ^ Emerson, D. T. (1997). "The work of Jagadis Chandra Bose: 100 years of mm-wave research". 1997 IEEE MTT-S International Microwave Symposium Digest, Vol. 3. IEEE Transactions on Microwave Theory and Research. Vol. 45, no. 12. pp. 2267–2273. Bibcode:1997imsd.conf..553E. doi:10.1109/MWSYM.1997.602853. ISBN 9780986488511. S2CID 9039614. reprinted in Igor Grigorov, Ed., Antentop, Vol. 2, No.3, pp. 87–96.
  10. ^ "Timeline". The Silicon Engine. Computer History Museum. Retrieved 22 August 2019.
  11. ^ "1901: Semiconductor Rectifiers Patented as "Cat's Whisker" Detectors". The Silicon Engine. Computer History Museum. Retrieved 23 August 2019.
  12. ^ a b c Golio, Mike; Golio, Janet (2018). RF and Microwave Passive and Active Technologies. CRC Press. pp. ix, I-1, 18–2. ISBN 9781420006728.
  13. ^ Rappaport, T. S. (November 1991). "The wireless revolution". IEEE Communications Magazine. 29 (11): 52–71. doi:10.1109/35.109666. S2CID 46573735.
  14. ^ "The wireless revolution". The Economist. 21 January 1999. Retrieved 12 September 2019.
  15. ^ a b c Baliga, B. Jayant (2005). Silicon RF Power MOSFETS. World Scientific. ISBN 9789812561213.
  16. ^ a b Harvey, Fiona (8 May 2003). "The Wireless Revolution". Encyclopædia Britannica. Retrieved 12 September 2019.
  17. ^ Tech Target – Definition of Wireless – Posted by Margaret Rouse (2 April control and traffic control systems
  18. ^ Tsai, Allen. "AT&T Releases Navigator GPS Service with Speech Recognition". Telecom Industry News. Archived from the original on 14 June 2012. Retrieved 2 April 2008.
  19. ^ "Robust demand for mobile phone service will continue; UN agency predicts". UN News Centre. 15 February 2010. Retrieved 6 September 2011.
  20. ^ Vilorio, Dennis. "You're a what? Tower Climber" (PDF). Occupational Outlook Quarterly. Archived (PDF) from the original on 3 February 2013. Retrieved 6 December 2013.
  21. ^ a b c "High Speed Internet on the Road". Archived from the original on 3 September 2011. Retrieved 6 September 2011.
  22. ^ "What is Connection Manager?". Microsoft Technet. 28 March 2003. Retrieved 6 September 2011.
  23. ^ "Our Products". Unwired Revolution. Archived from the original on 9 January 2012. Retrieved 6 September 2011.
  24. ^ "General Dynamics- NetMotion Mobility XE". Archived from the original on 26 September 2011. Retrieved 30 August 2011.
  25. ^ "Wi-Fi". Retrieved 6 September 2011.
  26. ^ O'Brien, J; Marakas, G.M (2008). Management Information Systems. New York, NY: McGraw-Hill Irwin. p. 239.
  27. ^ Aravamudhan, Lachu; Faccin, Stefano; Mononen, Risto; Patil, Basavaraj; Saifullah, Yousuf; Sharma, Sarvesh; Sreemanthula, Srinivas (4 July 2003). "Getting to Know Wireless Networks and Technology". InformIT. Retrieved 12 July 2011.
  28. ^ "What really is a Third Generation (3G) Mobile Technology" (PDF). ITU. Archived from the original (PDF) on 7 June 2011. Retrieved 12 July 2011.
  29. ^ Geier, Jim (2008). "Wireless Network Industry Report 2007" (PDF). Wireless-Nets, Ltd. Archived from the original (PDF) on 12 October 2012. Retrieved 6 September 2011.
  30. ^ Ilcev, Stojce Dimov (2006). Global Mobile Satellite Communications for Maritime, Land and Aeronautical Applications. Springer. ISBN 9781402027840.
  31. ^ Lewis, F.L. (2004). "Wireless Sensor Networks" (PDF). Smart Environments: Technologies, Protocols, and Applications. New York: John Wiley: 11–46. doi:10.1002/047168659X.ch2. ISBN 9780471686590.
  32. ^ Paventi, Jared (26 October 2013). "How does a Wireless Keyboard Work?". Ehow.
  33. ^ Moser, Max; Schrödel, Philipp (5 December 2007). "27Mhz Wireless Keyboard Analysis Report aka 'We know what you typed last summer'" (PDF). Archived from the original (PDF) on 23 January 2009. Retrieved 6 February 2012.
  34. ^ Jones, George (14 September 2010). "Future Proof: How Wireless Energy Transfer Will Kill the Power Cable". MaximumPC.
  35. ^ Dusit Niyato; Lotfollah Shafai (2017). Wireless-Powered Communication Networks. Cambridge University Press. p. 329. ISBN 978-1-107-13569-7. Retrieved 17 April 2021.
  36. ^ "First Demonstration of a Surveillance Camera Powered by Ordinary Wi-Fi Broadcasts". MIT Technology Review. Retrieved 20 November 2020.
  37. ^ Linebaugh, Kate (23 May 2012). "More Hospital Medical Devices to Go Wireless". The Wall Street Journal. Retrieved 13 May 2022.

Further reading

[edit]
  • Geier, Jim (2001). Wireless LANs. Sams. ISBN 0-672-32058-4.
  • Goldsmith, Andrea (2005). Wireless Communications. Cambridge University Press. ISBN 0-521-83716-2.
  • Larsson, Erik; Stoica, Petre (2003). Space-Time Block Coding For Wireless Communications. Cambridge University Press.
  • Molisch, Andreas (2005). Wireless Communications. Wiley-IEEE Press. ISBN 0-470-84888-X.
  • Pahlavan, Kaveh; Krishnamurthy, Prashant (2002). Principles of Wireless Networks – a Unified Approach. Prentice Hall. ISBN 0-13-093003-2.
  • Pahlavan, Kaveh; Levesque, Allen H (1995). Wireless Information Networks. John Wiley & Sons. ISBN 0-471-10607-0.
  • Rappaport, Theodore (2002). Wireless Communications: Principles and Practice. Prentice Hall. ISBN 0-13-042232-0.
  • Rhoton, John (2001). The Wireless Internet Explained. Digital Press. ISBN 1-55558-257-5.
  • Tse, David; Viswanath, Pramod (2005). Fundamentals of Wireless Communication. Cambridge University Press. ISBN 0-521-84527-0.
[edit]
Look up wireless in Wiktionary, the free dictionary.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Wireless&oldid=1234660861"