|
Code-division
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. Many carriers (such as AT&T, UScell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, which 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 mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UMTS
The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. UMTS uses Wideband Code Division Multiple Access, wideband code-division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators compared to previous 2G systems like GPRS and Circuit Switched Data, CSD. UMTS on its provides a peak theoretical data rate of 2 Data-rate units, Mbit/s. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing IS-95, cdmaOne technology. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM. UMTS specifies a complete network system, which includes the radio access network (UMTS Terrestrial Radio Access Network, or U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spread Spectrum
In telecommunications, especially radio communication, spread spectrum are techniques by which a signal (electrical engineering), signal (e.g., an electrical, electromagnetic, or acoustic) generated with a particular Bandwidth (signal processing), bandwidth is deliberately spread in the frequency domain over a wider frequency band. Spread-spectrum techniques are used for the establishment of secure communications, increasing resistance to natural Interference (communication), interference, Noise (electronics), noise, and radio jamming, jamming, to prevent detection, to limit Spectral flux density, power flux density (e.g., in satellite downlinks), and to enable multiple-access communications. Telecommunications Spread spectrum generally makes use of a sequential noise-like signal structure to spread the normally narrowband information signal over a relatively wideband (radio) band of frequencies. The receiver correlates the received signals to retrieve the original information ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible successor to second-generation cdmaOne (IS-95) set of standards and used especially in North America and South Korea. CDMA2000 compares to UMTS, a competing set of 3G standards, which is developed by 3GPP and used in Europe, Japan, China, and Singapore. The name CDMA2000 denotes a family of standards that represent the successive, evolutionary stages of the underlying technology. These are: *Voice: CDMA2000 1xRTT, 1X Advanced *Data: CDMA2000 1xEV-DO ( Evolution-Data Optimized): Release 0, Revision A, Revision B, Ultra Mobile Broadband (UMB) All are approved radio interfaces for the ITU's IMT-2000. In the United States, ''CDMA2000'' is a registered trademark of the Telecommunications Industry Association (TIA-USA). 1X CDMA200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthogonal Frequency-division Multiplexing
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission used in digital modulation for encoding digital (binary) data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/ 5G mobile communications. OFDM is a frequency-division multiplexing (FDM) scheme that was introduced by Robert W. Chang of Bell Labs in 1966. In OFDM, the incoming bitstream representing the data to be sent is divided into multiple streams. Multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted, with each carrier modulated with bits from the incoming stream so multiple bits are being transmitted in parallel. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide 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 telephone 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. Overview The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was launched in 1978 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CdmaOne
cdmaOne, most often simply referred to as CDMA, is a 2G digital cellular technology. It was the commercial name for Interim Standard 95 (IS-95), a technology that was developed by Qualcomm and later adopted as a standard by the Telecommunications Industry Association in TIA/EIA/IS-95 release published in 1995. cdmaOne used code-division multiple access (CDMA), a multiple access scheme for digital radio, to send voice, data and signaling data (such as a dialed telephone number) between mobile telephones and cell sites. CDMA transmits streams of bits ( PN codes). CDMA permits several radios to share the same frequencies. Unlike time-division multiple access (TDMA), a competing system used in 2G GSM, all radios can be active all the time, because network capacity does not directly limit the number of active radios. Since larger numbers of phones can be served by smaller numbers of cell-sites, CDMA-based standards have a significant economic advantage over TDMA-based stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Jamming
Radio jamming is the deliberate blocking of or interference with wireless communications.https://apps.fcc.gov/edocs_public/attachmatch/DA-12-347A1.pdf Enforcement Advisory No. 2012-02 FCC Enforcement Advisory Cell Jammers, GPS Jammers, and Other Jamming Devices Consumer Alert: Using or Importing Jammers is Illegal In some cases, jammers work by the transmission of radio signals that disrupt telecommunications by decreasing the signal-to-noise ratio. The concept can be used in wireless data networks to disrupt information flow. It is a common form of censorship in totalitarian countries, in order to prevent foreign radio stations in border areas from reaching the country. Jamming is usually distinguished from interference that can occur due to device malfunctions or other accidental circumstances. Devices that simply cause interference are regulated differently. Unintentional "jamming" occurs when an operator transmits on a busy frequency without first checking whether it is in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 * Gold, chemical symbol Au * 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 used in planetary systems astronomy * Arbitrary unit, a placeholder unit for when the actual value of a measurement is unknown or unimportant Arts and entertainment Music * AU (band), an experimental pop group headed by Luke Wyland * ''Au'', a 2010 release by Scottish rock band Donaldson, Moir and Paterson * ''Au'' a track on Some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 phone, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tekhnika Molodezhi
''Tekhnika Molodezhi'' (, "Technology for the Youth") is a 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. See also *'' Nauka i Zhizn'' (Science and Life) *'' Znanie – Sila'' "Knowledge is Power" References External linksТехника – молодежи ISSN 0320-331Х bibliography of science fiction Science fiction (often shortened to sci-fi or abbreviated SF) is a genre of speculative fiction that deals with imaginative and futuristic concepts. These concepts may include information technology and robotics, biological manipulations, space ... published in the magazine (1933-2020) 1933 establishments in the Soviet Union Magazines established in 1933 Popular science magazines Russian-language ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nauka I Zhizn
''Nauka i Zhizn'' (''Science and Life'', ) is a science magazine first issued during the years 1890–1900 in Russian Empire, and then since 1934 in the Soviet Union (and continued in the Russian Federation today). See also *Tekhnika Molodezhi ''Tekhnika Molodezhi'' (, "Technology for the Youth") is a 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 ... "Technology for the Youth" * Znanie — Sila "Knowledge is Power" 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
