Frequency Division Multiple Access or FDMA is an access technology that is used by radio systems to share the radio spectrum. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz The terminology “multiple access” implies the sharing of the resource amongst users, and the “frequency division” describes how the sharing is done: by allocating users with different carrier frequencies of the radio spectrum.
This technique relies upon sharing of the available radio spectrum by the communications signals that must pass through that spectrum. The terminology “multiple access” indicates how the radio spectrum resource is intended to be used: by enabling more than one communications signal to pass within a particular band; and the “frequency division” indicates how the sharing is accomplished: by allocating individual frequencies for each communications signal within the band.
In demand assigned multiple access (DAMA) systems, a control mechanism is used to establish or terminate voice and/or data links between the source and destination stations. Consequently, any of the subdivisions is used by any of the participating earth stations at any given time. An earth station or ground station is the surface-based (terrestrial end of a Communications link to an object in Outer space.
FDMA also supports demand assignment in addition to fixed assignment. Demand assignment allows all users apparently continuous access of the transponder bandwidth by assigning carrier frequencies on a temporary basis using a statistical assignment process. In Telecommunication, the term transponder (short-for Trans mitter-res ponder and sometimes abbreviated to XPDR XPNDR TPDR or TP has the following meanings The first FDMA demand-assignment system for satellite was developed by COMSAT for use on the Intelsat series IVA and V satellites. The Communications Satellite Corporation (COMSAT is a global Telecommunications company based in the USA, and with branches in Brazil, Argentina Intelsat Ltd is the world’s largest commercial Satellite communications services provider
In contrast to FDMA, Time Division Multiple Access (TDMA) is an access technique whereby users are separated in time. This article is about the medium access technology The name "TDMA" is also commonly used in the United States to refer to D-AMPS, which is a mobile telephone Code Division Multiple Access CDMA is an access technology whereby users are separated by codes. Code division multiple access ( CDMA) is a Channel access method utilized by various radio communication technologies Other access techniques include: SDMA – Space division multiple access, CSMA – Carrier sense multiple access, and MF-TDMA - Multi-Frequency TDMA
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Carrier Sense Multiple Access ( CSMA) is a Probabilistic Media Access Control (MAC protocol in which a node verifies the absence of other trafficDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic