MultiCarrierCodeDivisionMultipleAccess MC CDMA is a multipleaccess scheme used in OFDM based telecommunication systems, allowing the system to support multiple users at the same time. MC CDMA spreads each user symbol in the frequency domain. That is, each user symbol is carried over multiple parallel subcarriers, but it is phase shifted typically 0 or 180 degrees according to a code value. The code ... whitepapers whitepaper pdf service4.pdf MultiCarrierCodeDivisionMultipleAccess , March ... mcss2007 history.php History of MultiCarrierCodeDivisionMultipleAccess MC CDMA and MultiCarrier ... to one or more terminals , MC CDMA typically reduces to MultiCarrierCodeDivision Multiplexing ... and frequency spreading Orthogonal Frequency CodeDivisionMultipleAccess OFCDMA References references Literature N. Yee, J.P.M.G. Linnartz and G. Fettweis, MultiCarrier CDMA in indoor wireless ... form of multicarrier CDMA , called MC DS CDMA or MC DS CDMA, performs spreading in the time ... D spreading is VSF OFCDM which stands for variable spreading factor orthogonal frequency codedivision .... Fettweis, MultiCarrier CDMA in indoor wireless networks , IEICE Transaction on Communications, Japan .... Fazel and S. Kaiser, MultiCarrier and Spread Spectrum Systems From OFDM and MC CDMA to LTE and WiMAX ... OFDMA , an alternative multipleaccess scheme for OFDM systems, where the signals of different users ... these to compensate varying signal strengths and undo the code shift. The receiver can separate signals of different users, because these have different e.g. orthogonal code values. Since each ... this frequency domain spreading can take place, such as by using a long PN code and multiplying each data symbol, d sub i sub , on a subcarrier by a chip from the PN code, c sub i sub , or by using short PN codes and spreading each data symbol by an individual PN code &mdash i.e. d sub i sub is multiplied ... sub freq sub is the PN code length. Once frequency domain spreading has taken place and the OFDM subcarriers ... more details
can communicate. The technology of codedivisionmultipleaccess channels has long been known. In the USSR ... access methods DEFAULTSORT CodeDivisionMultipleAccess Category Codedivisionmultipleaccess Category ... por divisi n de c digo fa fr CodeDivisionMultipleAccess ko hi id CDMA it CodeDivisionMultipleAccess he CDMA ka CDMA hu K doszt sos t bbsz r s hozz f r s my nl Codedivisionmultipleaccess ja pl CDMA pt CDMA ru CDMA su CDMA fi CDMA sv CDMA ta te CDMA th CodeDivisionMultipleAccess tr CDMA uk CodeDivisionMultipleAccess ur vi a truy c p ph n chia theo m zh ...about a channel access method the mobile phone technology referred to as CDMA IS 95 and CDMA2000 Multiple issues lead rewrite November 2010 refimprove May 2009 Multiplex techniques Codedivisionmultipleaccess CDMA is a channel access method used by various radio communication technologies. It should ... multiple users to be multiplexed over the same physical channel. By contrast, time divisionmultipleaccess TDMA divides access by time , while frequency divisionmultipleaccess FDMA divides ... see bandwidth signal processing bandwidth . This concept is called multipleaccess . CDMA employs ... to the problem of multipleaccess is a room channel in which people wish to talk to each ... pitches frequency division , or speak in different languages codedivision . CDMA is analogous ... for codedivision multiplexing is in Global Positioning System GPS . This predates and is distinct ... Modulation CDMA is a spread spectrum multipleaccess ref cite book first Valeri last Ipatov year 2000 ... and asynchronous pseudorandom codes . Codedivision multiplexing Synchronous CDMA Synchronous CDMA ... into Problems of Wireless MultipleAccess edition 1st publisher VDM Verlag isbn 3639368940 ... referred to as simply CDMA , and use CDMA as an underlying channel access method. One of the concepts ... more details
in channel assignment is retained. See also Channel access methods Time division multiplex TDM Channel access methods Category Telecommunications terms ru MF TDMA ... more details
Merge to Codedivisionmultipleaccess date July 2010 Unreferenced stub auto yes date December 2009 In data communications, Synchronous CodeDivisionMultipleAccess or SCDMA , is a channel access method based on spread spectrum codedivisionmultipleaccess . See also TD SCDMA Channel access methods Category Multiplexing Telecomm stub ... more details
Carrier Sense MultipleAccess CSMA is a probabilistic Media Access Control MAC protocol in which a node verifies the absence of other Network traffic traffic before Transmission telecommunications transmitting on a shared transmission medium , such as an electrical bus, or a band of the electromagnetic spectrum . Carrier Sense describes the fact that a transmitter uses feedback from a receiver that detects a carrier wave before trying to send. That is, it tries to detect the presence of an encoded Signal electrical engineering signal from another station before attempting to transmit. If a carrier is sensed, the station waits for the transmission in progress to finish before initiating its own transmission. In other words, CSMA is based on the principle sense before transmit or listen before talk . MultipleAccess describes the fact that multiple stations send and receive on the medium. Transmissions ... Carrier sense multipleaccess with collision detection CSMA CD is a modification of CSMA ..., and reducing the probability of a second collision on retry. Carrier sense multipleaccess ... waits until the next available Time divisionmultipleaccess time slot and transmits again with the same ... 2003 . 892 pp. ISBN 0 13 066102 3 See also Local collision Remote collision Carrier sense multipleaccess with collision detection Carrier sense multipleaccess with collision avoidance Channel access methods Category Media access control cs CSMA de Carrier Sense MultipleAccess es Carrier sense multipleaccess eu CSMA fr CSMA it CSMA he Carrier sense multipleaccess my pl Carrier Sense MultipleAccess pt CSMA ru Carrier Sense MultipleAccess simple Carrier sense multipleaccess sr sv Carrier Sense MultipleAccess zh ... access modes 1 persistent When the sender station is ready to transmit data, it checks if the physical ... off between 1 and non persistent CSMA access modes. When the sender is ready to send data, it checks ... more details
one source date August 2009 Frequency DivisionMultipleAccess or FDMA is a channel access method used in multipleaccess protocols as a channelization protocol. FDMA gives users an individual allocation of one or several frequency band s, or channel communications channel s. It is particularly commonplace in satellite communication . FDMA, like other MultipleAccess systems, coordinates access between multiple users. Alternatives include Time divisionmultipleaccess TDMA , CDMA , or Space divisionmultipleaccess SDMA . These protocols are utilized differently, at different levels of the theoretical OSI model . Disadvantage Crosstalk may cause interference among frequencies and disrupt the transmission. Features In FDMA all users share the satellite simultaneously but each user transmits ... filters in the radio hardware, in contrast to Time divisionmultipleaccess TDMA and CDMA . FDMA is not vulnerable to the timing problems that Time divisionmultipleaccess TDMA has. Since a predetermined ... frequency division duplexing FDD . While FDMA allows multiple users simultaneous access to a transmission ... series IVA and V satellites. There are two main techniques Multi channel per carrier MCPC Single channel per carrier SCPC References reflist Olenewa, J. & Ciampa, M. 2007 . Wireless Guide to Wireless Communications 2nd ed. . Boston, United States THOMSON COURSE TECHNOLOGY Channel access methods Telecommunications ... por divisi n de frecuencia fr Acc s multiple par r partition en fr quence it Frequency divisionmultipleaccess he xDMA ja pl FDMA pt FDMA ru FDMA fi FDMA ... division multiplexing FDM is also distinct from FDMA. FDM is a physical layer technique that combines ..., is an access method in the data link layer . FDMA also supports demand assignment in addition to fixed assignment. Demand assignment allows all users apparently continuous access of the radio spectrum by assigning carrier frequencies on a temporary basis using a statistical assignment process. The first ... more details
Unreferenced stub auto yes date December 2009 Polarization divisionmultipleaccess PDMA is a channel access method used in some cellular network s. Separate antenna radio antennas are used in this type, each with different polarization waves polarization and followed by separate receivers, allowing simultaneous regional access of satellite s. Each corresponding earth station antenna needs to be polarized in the same way as its counterpart in the satellite. This is generally accomplished by providing each participating earth station with an antenna that has dual polarization. The frequency band allocated to each antenna beam can be identical because the uplink signals are orthogonal in polarization. This technique allows frequency reuse . See also frequency divisionmultipleaccesscodedivisionmultipleaccess time divisionmultipleaccess Channel access methods DEFAULTSORT Polarisation DivisionMultipleAccess Telecomm stub ... more details
Multiple issues confusing May 2009 context May 2009 unreferenced May 2009 Wavelength DivisionMultipleAccess WDMA is a channel access method based on wavelength division multiplexing . Channel access methods electronics stub comm stub it WDMA ... more details
match the gap in transmission from its peers. TDMA characteristics Shares single carrier frequency with multiple users Non continuous transmission makes handoff simpler Slots can be assigned on demand in dynamic TDMA Less stringent power control than Codedivisionmultipleaccess CDMA due to reduced ... that uses TDMA to control channel access. Time divisionmultipleaccess TDMA is a channel access ... method for data transmission control. Comparison with other multipleaccess schemes In radio systems, TDMA is usually used alongside Frequency divisionmultipleaccess FDMA and Frequency division .... Dynamic TDMA In dynamic time divisionmultipleaccess , a scheduling algorithm dynamically reserves ... Channel access methods Time division multiplex TDM Duplex telecommunications FDD,TDD Link 16 References Reflist Channel access methods DEFAULTSORT Time DivisionMultipleAccess Category Telecommunications ... TDMA it Time DivisionMultipleAccess he xDMA nl Time divisionmultipleaccess ja pl TDMA pt TDMA ru TDMA fi TDMA sv TDMA uk Time divisionmultipleaccess zh ... systems are primarily based upon CDMA Citation needed date February 2011 , time division duplexing TDD , packet scheduling dynamic TDMA and packet oriented multipleaccess schemes are available in 3G ... radio access network. IEEE 802.16a WiMax Bluetooth The Packet radio multipleaccess PRMA method ...refimprove date August 2011 This article is about the channel access method. The name TDMA is also commonly ..., each using its own time slot. This allows multiple stations to share the same transmission ... into time slots. TDMA is a type of Time division multiplexing , with the special point that instead of having one transmitter connected to one Receiver radio receiver , there are multiple transmitters ... form of the UMTS 3G system uses CDMA and frequency division duplex ing FDD instead of TDMA, TDMA is combined with CDMA and Time Division Duplexing in two standard UMTS UTRA TDMA in wired networks ... more details
Multiple issues orphan July 2010 notability July 2010 no footnotes July 2010 wikify March 2012 Quadrature DivisionMultipleAccess QDMA is a radio protocol. ref cite book last Held first Gilbert title Wireless mesh networks year 2005 publisher CRC Press isbn 9780849329609 pages 44 url http books.google.com books?id FdHevsDK3mEC&pg PA44 ref The term combines two standard terms in telecommunications, CDMA and QPSK . Applications QDMA is used for local area networks, usually wireless short range such as WiMax. CDMA and QDMA are especially suitable for modern communications, for example the transmission of short messages such as SMS or MMS communication when in motion from cars, trains, etc. the establishment of unplanned links. Benefits over TDMA and FDMA Unreferenced section date July 2010 The traditional TDMA and FDMA require a lot of overhead to set explain a link parameters grammatical problem with a new user, or to detect that a user left and their allocation is free to be allocated to another. In CDMA or QDMA, a new user is simply allocated a new code and is ready to go. It may impose a slight load on the spectrum, but the system is so devised as to absorb a controlled measure of collisions and continue operations at a high level of quality of service. References Reflist John G. Proakis, Digital Communications, Third Edition, ISBN 0 07 051726 6 Ulrich L. Rohde, Jerry Whitaker, T.T.N.Bucher, Communications Receivers, Second Edition, ISBN 0 07 053608 2 Category Channel access methods ... more details
Unreferenced date December 2009 Space DivisionMultipleAccess SDMA is a channel access method based on creating parallel spatial pipes next to higher capacity pipes through spatial multiplexing and or diversity, by which it is able to offer superior performance in radio multipleaccess communication systems. In traditional mobile cellular network systems, the base station has no information on the position of the mobile units within the cell and radiates the signal in all directions within the cell in order to provide radio coverage. This results in wasting power on transmissions when there are no mobile units to reach, in addition to causing co channel interference interference for adjacent cells using the same frequency, so called co channel cells. Likewise, in reception, the Antenna radio antenna receives signals coming from all directions including noise and interference signals. By using smart antenna technology and differing spatial locations of mobile units within the cell, space divisionmultipleaccess techniques offer attractive performance enhancements. The radiation pattern of the base station, both in transmission and reception, is adapted to each user to obtain highest gain in the direction of that user. This is often done using phased array techniques. In GSM cellular networks, the base station is aware of the mobile phone s position by use of a technique called timing advance TA . The Base Transceiver Station BTS can determine how distant the Mobile Station MS is by interpreting the reported TA. This information, along with other parameters, can then be used to power down the BTS or MS, if a power control feature is implemented in the network. The power control ... at any given time. See also Co channel interference Channel access methods DEFAULTSORT Space DivisionMultipleAccess ca Acc s m ltiple per divisi d espai es Acceso m ltiple por divisi n de espacio pl SDMA th Space DivisionMultipleAccess ... more details
Image CSMACD Algorithm.svg thumb right 440px Simplified Algorithm of CSMA CD Carrier sense multipleaccess with collision detection CSMA CD is a Media Access Control method in which ref cite web url http learn networking.com network design carrier sense multipleaccess collision detect csmacd explained title Carrier Sense MultipleAccess Collision Detect CSMA CD Explained accessdate 2011 07 29 ref a Carrier wave carrier sensing scheme is used. a transmitting data station that detects another Transmission telecommunications signal while transmitting a frame telecommunications frame , stops transmitting that frame, transmits a jam signal, and then waits for a random time interval before trying to resend the frame. CSMA CD is a modification of pure carrier sense multipleaccess CSMA . CSMA CD is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus ... IEEE 802.3 Channel access methods DEFAULTSORT Carrier Sense MultipleAccess With Collision Detection Category Media access control Category Ethernet cs CSMA CD da CSMA CD de Carrier Sense MultipleAccess Collision Detection et CSMA CD es Carrier sense multipleaccess with collision detection eu CSMA CD fr Carrier Sense MultipleAccess with Collision Detection gl CSMA CD ko id CSMA CD it CSMA CD hu Carrier Sense MultipleAccess with Collision Detection mk CSMA CD nl CSMA CD ja CSMA CD pl CSMA CD pt CSMA CD ru CSMA CD simple Carrier sense multipleaccess with collision detection ... fi CSMA CD sv Carrier sense multipleaccess with collision detection tr CSMA CD vi CSMA CD zh ... Std 802.3 , which defines all Ethernet variants, for historical reasons still bears the title Carrier sense multipleaccess with collision detection CSMA CD access method and physical layer specifications ... , including Automatic Packet Reporting System . Citation needed date July 2010 See also Carrier sense multipleaccess with collision avoidance CSMA CA Collision domain Late collision Ethernet Notes ... more details
Carrier sense multipleaccess with collision avoidance CSMA CA , in computer network ing, is a wireless network multipleaccess method in which a Carrier wave carrier sensing scheme is used. a Node networking node wishing to transmit data has to first listen to the channel for a predetermined amount of time to determine whether or not another node is transmitting on the channel within the wireless range. If the channel is sensed idle, then the node is permitted to begin the transmission process. If the channel is sensed as busy, the node defers its transmission for a random period of time. Once ... Glossary 2000 ref CSMA CA is a modification of carrier sense multipleaccess . Collision telecommunications ... over coax coaxial cables , uses CSMA CA as a channel access method for flows that don t require guaranteed quality of service , specifically the CSMA CARP variant. See also Carrier sense multipleaccessCarrier sense multipleaccess with collision detection CSMA CARP IEEE 802.11 RTS CTS Truncated ... Channel access methods DEFAULTSORT Carrier Sense MultipleAccess With Collision Avoidance Category IEEE 802.11 ca CSMA CA cs CSMA CA da CSMA CA de Carrier Sense MultipleAccess Collision Avoidance es Carrier sense multipleaccess with collision avoidance eu CSMA CA fa fr Carrier Sense MultipleAccess with Collision Avoidance it CSMA CA he Carrier sense multipleaccess CSMA CA nl CSMA CA ja CSMA CA pl CSMA CA pt CSMA CA ru CSMA CA fi CSMA CA sv Carrier sense multipleaccess with collision avoidance zh CSMA CA ... 504583 5. ref CSMA CA is a layer 2 access method, not a protocol of the OSI model. ref name eunice http ... access method to be implemented. CSMA CA is used in 802.11 based wireless LAN s and other wired and wireless .... 802.11 RTS CTS implements virtual carrier sensing using short request to send and clear to send messages for Wireless LAN WLAN s 802.11 mainly relies on physical carrier sensing though . IEEE 802.15.4 ... more details
Multiplex techniques Orthogonal Frequency DivisionMultipleAccess OFDMA is a multi user version of the popular orthogonal frequency division multiplexing OFDM digital modulation scheme. Multipleaccess ... and error probability individually for each user. OFDMA resembles codedivisionmultipleaccess CDMA spread spectrum, where users can achieve different data rates by assigning a different code spreading ... Int l. J. of Communications, 1 4 , 2007 173 179 See also Codedivisionmultipleaccess Frequency divisionmultipleaccess Time divisionmultipleaccess Single carrier FDMA SC FDMA , a.k.a. Linearly ... to combining OFDM with time divisionmultipleaccess TDMA or time domain statistical multiplexing ... Docs Tutorils OFDMA BCW cv6.pdf Orthogonal Frequency DivisionMultipleAccess is it the multipleaccess ... 2004. Channel access methods ca OFDMA es Orthogonal Frecuency DivisionMultipleAccess it Orthogonal frequency divisionmultipleaccess ja uk OFDMA zh OFDMA ... several users. Pulsed carrier can be avoided. Lower maximum transmission power for low data rate users. Shorter delay, and constant delay. Contention based multipleaccess collision avoidance is simplified .... OFDMA can also be described as a combination of frequency domain and time domain multipleaccess ... references Literature K. Fazel and S. Kaiser, MultiCarrier and Spread Spectrum Systems From OFDM .... ref name yin Averaging interferences from neighboring cells, by using different basic carrier permutations ... services such as web access are characterized by short communication bursts at high data rate ... if very few sub carriers are assigned to each user, and if the same carrier is used in every OFDM symbol. Adaptive sub carrier assignment based on fast feedback information about the channel, or sub carrier frequency hopping, is therefore desirable. Dealing with co channel interference from nearby ... sub carrier assignment is more complex than CDMA fast power control. Characteristics and principles ... more details
Multiple issues context June 2009 notability June 2009 unreferenced June 2009 orphan December 2010 Channel DivisionMultipleAccess ChDMA is a simple Multi user multipleaccess scheme developed for low duty cycle Ultra wideband UWB networks. The idea lies in the fact that different users have different Channel communications channel impulse response CSI and the signal at the receiver can be rebuilt based on this information. See also Blind equalization Multiplexing DEFAULTSORT Channel DivisionMultipleAccess Chdma Category Data transmission Category Telecommunication theory Category Signal processing radio comm stub ... more details
Self Organized Time DivisionMultipleAccess STDMA is a channel access method which was designed by H kan Lans , ref name patent cite patent country US number 5506587 status patent title Position indicating system gdate 1996 04 09 fdate 1993 12 23 pridate 1991 07 01 inventor Lans, H kan invent1 Lans, H kan assign1 GP&C Systems International AB ref based on time division multiplexing . The term Self Organized describes the manner in which time slots are assigned to users. Time divisionmultipleaccess TDMA divides a channel into Frame telecommunications frames , which furthermore are subdivided into a vast number of time slots. Users transmit in rapid succession, one after the other, each using his own time slot. One of the drawbacks of TDMA is that it requires a central station for slot assignment and time synchronisation. STDMA proposes a method for assigning slots without the involvement of a central station. Time synchronisation is usually taken care of using Coordinated Universal Time UTC . STDMA is in use by the Automatic Identification System AIS , a standard marine short range coastal tracking system, and is the base of the International Civil Aviation Organization VHF Data Link ICAO VDL Mode 4 VHF Data Link Mode 4 . While the method was patented, ref name patent a United States Patent and Trademark Office US patent ex parte reexamination certificate was issued in 2010 canceling all claims. ref United States Patent and Trademark Office USPTO ex parte reexamination certificate 7428th , issued on March 30, 2010 ref References reflist External links dmoz Computers History Pioneers Lans, H c3 a5kan http www.gpc.se GP&C Systems International AB Channel access methods Category Maritime communication ... more details
wiktionary AccesscodeAccesscode may refer to In authentication Password , a secret word. Personal identification number PIN , a secret numeric code. In telecommunications Trunk prefix National accesscode , used to dial a domestic call. List of international call prefixes International accesscode , used to dial an international call. Area code , a segment of a telephone number. disambig fa ... more details
the body that manages the UMTS standards Codedivisionmultipleaccess CDMA Codedivisionmultipleaccess Time divisionmultipleaccess TDMA Time divisionmultipleaccess Frequency divisionmultipleaccess FDMA Frequency divisionmultipleaccess External links http www.3gpp.org ftp Specs archive 25 ...Opportunity Driven MultipleAccess ODMA is a UMTS communications relaying protocol standard first introduced by the European Telecommunication Standards Institute ETSI in 1996. ODMA has been adopted by the 3rd Generation Partnership Project, 3GPP to improve the efficiency of UMTS networks using the Time division duplex TDD mode. One of the objectives of ODMA is to enhance the capacity and the coverage of radio transmissions towards the boundaries of the cell. While mobile stations under the cell coverage area can communicate directly with the base station, mobile stations outside the cell boundary can still access the network and communicating with the base station via multihop transmission. Mobile stations with high data rate inside the cell are used as multihop relays. The initial concept of Opportunity Driven MultipleAccess ODMA was conceived and patented in South Africa by David Larsen and James Larsen of SRD Pty Ltd in 1978 http www.iwics.com Technology ODMAHistory.shtml The ODMA standard was tabled by the 3GPP committee in 1999 due to complexity issues. The technology continues to be developed and enhanced by IWICS who holds the key patents describing the methods employed in ODMA to effect opportunity driven communications. Image ODMA.jpg 600px thumb center ODMA border coverage ODMA Technology Basic Concepts With the explosion of cellular phone use and Internet multi media services, wireless networks are becoming increasingly congested. The increased demand has raised our expectations, while creating capacity problems and a need for greater bandwidth. However, if the transmitted ... radio frequency and path. Opportunity Driven MultipleAccess ODMA continually determines optimal ... more details
resource allocation and should not be confused with the Multipleaccess multiplexing methods such as FDMA frequencies, Time divisionmultipleaccess TDMA slots, CDMA codes, or others intended to divide a single communication channel into multiple virtual channels. These systems typically use resource ... based on demand and data priority. However, in sparsely allocated multipleaccess channels, DAMA can be used to allocate the individual virtual channel resources provided by the multipleaccess ...about the information technology Dama disambiguation Multiple issues expert Telecommunications refimprove August 2009 date March 2011 Demand Assigned MultipleAccess DAMA is a technology used to assign a Channel communications channel to clients that don t need to use it constantly. DAMA systems assign communication channels based on requests issued from user terminals to a network control system. When the circuit is no longer in use, the channels are then returned to the central pool for reassignment to other users. Channels are typically a pair of carrier frequencies one for transmit and one for receive , but can be other fixed bandwidth resources such as timeslots in a TDMA burst plan or even physical party line telephony party line channels. Once a channel is allocated to a given pair of nodes, it is not available to other users in the network until their session is finished. It allows utilizing of one channel radio or baseband frequency, timeslot , etc. by many users sequentially at different times . This technology is mainly useful with sparsely used networks of transient clients, as opposed to PAMA Permanently Assigned MultipleAccess . By using DAMA technology the number of separate ... being able to provide simultaneous access for all possible pairs of nodes. A five channel DAMA ... multiple users each having a low to moderate usage profile. DAMA is often used in military environments ... multiple access.shtml Category Telecommunication theory ... more details
unreferenced date December 2007 MultipleAccess with Collision Avoidance MACA is a slotted media access control protocol used in wireless LAN data transmission to avoid collisions caused by the hidden station problem and to simplify exposed station problem . The basic idea of MACA is a wireless network node makes an announcement before it sends the data frame to inform other nodes to keep silent. When a node wants to transmit, it sends a signal called Request To Send RTS with the length of the data frame to send. If the receiver allows the transmission, it replies the sender a signal called Clear To Send CTS with the length of the frame that is about to receive. br Meanwhile, a node that hears RTS should remain silent to avoid conflict with CTS a node that hears CTS should keep silent until the data transmission is complete. WLAN data transmission collisions may still occur, and the MACA for Wireless MACAW is introduced to extend the function of MACA. It requires nodes sending acknowledgements after each successful frame transmission, as well as the additional function of Carrier sense. External links Phil Karn http www.scribd.com doc 7853445 Maca MACA A New Channel Access Method for Packet Radio Phil Karn, KA9Q Please add the links and sources in alphabetical order. This is an encyclopedia. Channel access methods telecom stub DEFAULTSORT MultipleAccess With Collision Avoidance Category Media access control de Carrier Sense MultipleAccess Collision Avoidance RTS CTS Koordination es Multipleaccess with collision avoidance eu MultipleAccess Collission Avoidance ... more details
dablink This article is about the channel access method. For other uses, see Pama disambiguation . In telecommunications , pulse address multipleaccess PAMA is a channel access method that enables the ability of a communication satellite to receive signals from several Earth terminals simultaneously and to amplify, translate, and relay the signals back to Earth, based on the addressing of each Ground station station by an assignment of a unique combination of time and frequency slots. This ability may be restricted by allowing only some of the terminals Access control access to the satellite at any given time. References FS1037C MS188 Channel access methods Category Telecommunications telecomm stub ... more details
refimprove date July 2011 Deleted image removed File EMAS Information Card 3rd Edition January 1978.jpg thumb right EMAS Information Card 3rd Edition January 1978 The Edinburgh Multi Access System EMAS was a mainframe computer operating system developed at the University of Edinburgh , Scotland , during the 1970s. EMAS was developed because none of the manufacturers operating systems nor independent systems such as Multics came close to satisfying the demanding performance requirements of Edinburgh University. Originally running on the ICL System 4 75 mainframe based on the design of the IBM 360 it was later reimplemented ref http www.gtoal.com athome edinburgh docs Experiment again.html ref on the ICL 2900 ICL 2900 series of mainframes as EMAS 2900 or EMAS 2 where it ran in service until the mid 1980s. Near the end of its life, the refactored version was back ported as EMAS 3 to the IBM System 370 XA architecture again, running on Amdahl Corporation Amdahl 470 and NAS VL80 IBM mainframe clones into the early 1990s. It was a powerful and efficient general purpose multi user system which supplied all the computing needs of Edinburgh University and the University of Kent the only other site outside Edinburgh to adopt the operating system . The final EMAS system the Edinburgh VL80 was decommissioned in July 1992. EMAS had several advanced for the time features, including dynamic linking , multi level storage, an efficient scheduling computing scheduler , a separate user space kernel computing kernel director , a user level shell computing shell basic command interpreter , and a memory mapped file architecture. Such features lead EMAS supporters to claim that their system was superior to Unix for the first 20 years of the latter s existence. The Edinburgh Computer History Project is attempting to salvage some of the lessons learned ref http history.dcs.ed.ac.uk archive os emas docs taste ref from the EMAS project and has the complete source code of EMAS online for publi ... more details
Unreferenced stub auto yes date December 2009 A Multi service access Node MSAN also known as a Multi service access gateway MSAG is a device typically installed in a telephone exchange although sometimes in a roadside serving area interface cabinet which connects customers telephone lines to the core network , to provide telephone , ISDN , and broadband such as DSL all from a single platform. Prior to the deployment of MSANs, telecom providers typically had a multitude of separate equipment including DSLAM s to provide the various types of services to customers. Integrating all services on a single node, which typically backhaul telecommunications backhaul s all data streams over Internet Protocol IP or Asynchronous Transfer Mode can be more cost effective and may provide new services to customers quicker than previously possible. A typical outdoor MSAN cabinet consists of narrowBand Plain old telephone service POTS , broadBand xDSL services, batteries with rectifiers, Fiber optic communication optical transmission unit and copper distribution frame . See also Next generation network DEFAULTSORT Msan Category Telephony equipment Category Digital subscriber line Telecomm stub ca Node d acc s multiservei es Nodo de acceso multiservicio it MSAN ru Multi Service Access Node tr MSAN uk MSAN vi MSAN ... more details
In biology or medicine, a multiaccess key is an identification key which overcomes the problem of the more traditional single access key s dichotomous key dichotomous or polytomous key polytomous identification keys of requiring a fixed sequence of identification steps. A multiaccess key enables the user to freely choose the set and characteristics that are convenient to evaluate for the item to be identified. ref name autogenerated2 Pankhurst, R. J. 1991. Practical Taxonomic Computing. ref ref name autogenerated3 Winston, J. 1999. Describing Species. Columbia University Press. ref Although good single access keys will try to start with characters that are reliable, convenient to observe and generally available throughout most of the year, it is often impossible to achieve this for all taxa in a key. A multiaccess key lets the user adapt the key to the particular organism that is being identified and to the circumstances of identification e.g. field or laboratory . Multiaccess keys may be printed in various way tabular, matrix, formula style, etc. but are more commonly used as computer aided, interactive keys. Alternative terms Alternative terms used for multiaccess keys are random access key , multi entry key , polyclave , matrix key , tabular key , synoptic key . Some of these terms should be avoided in this sense, however True multi entry key s exist. The terms tabular key and matrix key are best limited to a tabular presentation format of multiaccess keys. ref Fig. 19.6 in Winston, J. 1999. Describing Species. Columbia University Press. ref The term synoptic key has an older definition, defining it as a key reflecting taxonomic classification and opposed to diagnostic keys arranged solely for the convenience of identification. ref Pankhurst, R. J. 1992. Practical Taxonomic Computing. ref History Interactive multiaccess keys are a high tech descendent of card ... Advantages and disadvantages Multiaccess keys largely serve the same purpose as single access dichotomous ... more details
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