Code-division Multiple Access
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Code-division Multiple Access
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread spectrum technology and a special coding scheme (where each transmitter is assigned a code). CDMA optimizes the use of available bandwidth as it transmits over the entire frequency range and does not limit the user's frequency range. It is used as the access method in many mobile phone standards. IS-95, also called "cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and TD-SCDMA, as its radio technologies. It can be also used as a channel or m ...
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Channel Access Method
In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminals connected to the same transmission medium to transmit over it and to share its capacity. Examples of shared physical media are wireless networks, bus networks, ring networks and point-to-point links operating in half-duplex mode. A channel access method is based on multiplexing, that allows several data streams or signals to share the same communication channel or transmission medium. In this context, multiplexing is provided by the physical layer. A channel access method may also be a part of the multiple access protocol and control mechanism, also known as medium access control (MAC). Medium access control deals with issues such as addressing, assigning multiplex channels to different users and avoiding collisions. Media access control is a sub-layer in the data link layer of the OSI model and a component of the link layer of the TCP/IP model. Fundame ...
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Massachusetts Institute Of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the most prestigious and highly ranked academic institutions in the world. Founded in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. MIT is one of three private land grant universities in the United States, the others being Cornell University and Tuskegee University. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River, and encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory, the Bates Center, and the Haystack Observatory, as well as affiliated laboratories such as the Broad and Whitehead Institutes. , 98 ...
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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 systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ...
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Au CDMA 1X WIN W31SAII Gravelly Silver Expansion
Au, AU, au or a.u. may refer to: Science and technology Computing * .au, the internet country code for Australia * Au file format, Sun Microsystems' audio format * Audio Units, a system level plug-in architecture from Apple Computer * Adobe Audition, a sound editor program * Windows Update or Automatic Updates, in Microsoft Windows * Windows 10 Anniversary Update, of August 2016a Physics and chemistry * Gold, symbol Au (from Latin ), a chemical element * Absorbance unit, a reporting unit in spectroscopy * Atomic units, a system of units convenient for atomic physics and other fields * Ångström unit, a unit of length equal to 10−10 m or 0.1 nanometre. * Astronomical unit, a unit of length often used in Solar System astronomy, an approximation for the average distance between the Earth and the Sun * Arbitrary unit, a relative placeholder unit for when the actual value of a measurement is unknown or unimportant ("a.u." is deprecated, use "arb. unit" instead) Arts and entertain ...
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Altai (mobile Telephone System)
The Altai mobile telephone system is the pre-cellular 0G radiotelephone service that was first introduced in the Soviet Union in 1963, and became available in the most large cities by 1965. It is a fully automated UHF/ VHF network that allows a mobile node to connect to a landline phones, and was originally conceived to serve government officials and emergency services, but has since spread into general use, and is still in use in some places, where its advantages outweigh those of conventional cellular networks. Work on the system of automatic duplex mobile communication started in 1958 in Voronezh Research Institute of Communications (VNIIS, now concern Sozvezdie). It was established subscriber stations and base stations for communicating with them. Technical information From the technical standpoint "Altai" was fairly ordinary UHF/VHF trunked radio, but it was equipped with the automatic switching circuits on both mobile and static nodes that allowed the mobile end of the link ...
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Tekhnika Molodezhi
''Tekhnika Molodezhi'' (russian: Техника — молодёжи, "Technology for the Youth") is a Soviet Union, Soviet, and eventually Russian popular science magazine which has been published monthly since 1933. History and profile ''Tekhnika Molodezhi'' was established in 1933. During the Soviet era, it was often the first publisher of foreign science fiction authors in the USSR. The magazine had a science fiction section. References External linksOfficial website Journal Archive 1933-2012
1933 establishments in the Soviet Union Magazines established in 1933 Popular science magazines Russian-language magazines Monthly magazines published in Russia Science and technology magazines published in Russia Magazines published in the Soviet Union Soviet science fiction Science and technology in the Soviet Union {{Russia-stub ...
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Nauka I Zhizn
''Nauka i Zhizn'' (''Science and Life'', russian: Наука и жизнь) is a science magazine first issued during the years 1890–1900 in Imperial Russia, and then since 1934 in the Soviet Union (and continued in the Russian Federation Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ... today). References External links''Nauka i Zhizn'' website 1890 establishments in the Russian Empire Magazines established in 1890 Magazines published in Moscow Magazines published in the Soviet Union Popular science magazines Russian-language magazines Science and technology magazines published in Russia Science and technology in the Soviet Union {{Europe-sci-mag-stub ...
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Leonid Kupriyanovich
Leonid Ivanovich Kupriyanovich (, 14 July 1929 – 1 January 1996) was a Soviet engineer from Moscow who is credited for early development of a mobile phone device. Career In 1953 Kupriyanovich graduated MSTU named after N. Bauman. In 1955 Leonid Kupriyanovich published the description of a simple walkie-talkie amateur radio station for personal use in the Soviet amateur radio magazine "Radio," 1955, N2. It operated on two vacuum tubes. The walkie-talkie weighed about 1.2 kg and had 1.5 km operating distance. In 1957 Leonid Kupriyanovich presented a micro walkie-talkie radio version the size of a matchbox, 50g in weight and had 2 km operating distance. Also in 1957 he made an experimental model of a wearable automatic radio landline extender ("radiophone"), called LK-1 (not to be confused with the cancelled Soviet spacecraft of the same name or LK-1 ( ЛК-1) the first Soviet trolleybus). His device consisted of a stationary module and a portable handset. LK- ...
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Dmitry Vasiliyevich Ageev
Dmitry Vasilyevich Ageyev (russian: Дмитрий Васильевич Агеев; 21 February 1911 in Saint Petersburg, Russian Empire – 31 July 1997 in Nizhny Novgorod, Russia) was a Soviet and Russian scientist and educator in the field of radio engineering. He developed the theory of code division of signals during the radio reception, which is the basis for the construction of cellular networks on CDMA technology. Along with Vladimir Kotelnikov, he was one of the founders of the theory of optimum noise immunity that he developed throughout life, starting with a thesis at his institute. Biography Dmitry V. Ageyev was admitted to the Radio Engineering Faculty of the Leningrad Electrotechnical Institute of Communications (LEIS) in 1930, where he learnt from the scientists of his time, such as a founder of the national radio engineering and correspondent member of Academy of Sciences of the Soviet Union M. A. Bonch-Bruyevich, Professor Vladimir Tatarinov and others. In 193 ...
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Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national republics; in practice, both its government and its economy were highly centralized until its final years. It was a one-party state governed by the Communist Party of the Soviet Union, with the city of Moscow serving as its capital as well as that of its largest and most populous republic: the Russian SFSR. Other major cities included Leningrad (Russian SFSR), Kiev (Ukrainian SSR), Minsk ( Byelorussian SSR), Tashkent (Uzbek SSR), Alma-Ata (Kazakh SSR), and Novosibirsk (Russian SFSR). It was the largest country in the world, covering over and spanning eleven time zones. The country's roots lay in the October Revolution of 1917, when the Bolsheviks, under the leadership of Vladimir Lenin, overthrew the Russian Provisional Government ...
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Engineering And Technology History Wiki
The Engineering and Technology History Wiki (ETHW) is a MediaWiki-based website dedicated to the history of technology. It started operating in 2015. It consists of articles, first-hand accounts, oral histories, landmarks and milestones. A partnership between the United Engineering Foundation (UEF) and its member engineering organizations ASCE, AIME, AIChE, ASME, IEEE as well as the Society of Women Engineers is developing the ETHW as a central repository for the documentation, analysis and explanation of the history of technology. Origins In September 2008, the ''IEEE History Committee'' founded the ''IEEE Global History Network'', which operated from 2008 to 2014. The ETHW became successor to the former ''IEEE Global History Network (IEEE GHN)''. Originally, the United Engineering Foundation had made a grant to develop an engineering intersociety web platform as a central historical repository. Initially, the work was mainly done at the IEEE History Center. annexed to the Ste ...
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MIT Lincoln Laboratory
The MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense federally funded research and development center chartered to apply advanced technology to problems of national security. Research and development activities focus on long-term technology development as well as rapid system prototyping and demonstration. Its core competencies are in sensors, integrated sensing, signal processing for information extraction, decision-making support, and communications. These efforts are aligned within ten mission areas. The laboratory also maintains several field sites around the world. The laboratory transfers much of its advanced technology to government agencies, industry, and academia, and has launched more than 100 start-ups. History Origins At the urging of the United States Air Force, the Lincoln Laboratory was created in 1951 at the Massachusetts Institute of Technology (MIT) as part of an effort to improve the U.S. air defense syste ...
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