Konten dihapus Konten ditambahkan
Hadiyana (obrolan | kontribusi)
ngeureuyeuh saeutik nuluykeun hanca tarjamahan sanajan sibuk
Hadiyana (obrolan | kontribusi)
réngsé narjamahkeun
Baris ka-4:
==Téknologi==
 
AMPS ngarupakeun téknologi [[sélulér]] generasi munggaran ([[1G]]) nu ngagunakeun frékuénsi atawa kanal nu béda pikeun tiap panelepon (tempo [[FDMA]]). Temahna, ieu téknologi merlukeun [[rubakpita]] nu lega. Dina istilahSacara umum, AMPS sarupa pisan jeung "0G" nu leuwih ti heula, ngan baé ngagunakeun daya komputasi nu leuwih loba pikeun milih frékuénsi, pikeun ''hand off'' ka sambungannomer-nomer sambungan [[PSTN]], sarta nguruspikeun ngatur tagihan jeung [[call setup]].
 
Nu ngabédakeun AMPS ti téknologi lianna nu leuwih kolot nyaéta ayana "back end" ''call setup functionality''. Dina AMPS, puseur-puseur sél bisa sacara fléksibel méré kanal kana ''handset'' dumasar kana kuatna sinyal nu dipancarkeun ku ''handset'', temahna frékuénsi nu sarua bisa digunakeun deui di patempatan lianna tanpa ngakibatkeun gangguan. TemahnaTumerapna, AMPS bisa ngaladénan réa nomer langganan dina wilayah tinangtu. AMPS jadi panaratas istilah "sélulér" lantaran ieu téknologi nu munggaran ngagunakeun sél-sél héksagonal nu leutik dina sahiji sistem. <ref name="bell_young">W. Rae Young, "AMPS: Introduction, Background, and Objectives", Bell System Technical Journal, vol. 58, 1, pages 1-14, January 1979. ''(Note: Young was the Bell Labs engineer who invented the hexagonal cell concept.)''</ref><ref name="bell_porter">Z. C. Fluhr and Philip T. Porter, "AMPS: Control Architecture", Bell System Technical Journal, vol. 58, 1, pages 1-14, January 1979. ''(Note: Porter was the Bell Labs engineer who proposed that the cell towers be at the corners of the hexagons rather than the centers and have directional antennas that would transmit/receive in 3 directions into 3 adjacent hexagon cells.)''</ref>
 
Aya sawatara kakurang AMPS lamun dibandingkeun jeung téknologi digital kiwari. Lantaran ieu téknologi sifatna analog, AMPS uduh pisan ku gangguan statik jeung nois sarta teu boga panyalindungan tina ''panguping''panyadap (basa Indonesia: penyadap) sora nu ngagunakeun [[Scanner (radio)|scanner]]. Dina taun 1990-an, "cloning" ngarupakeun panyakit épidemik nu ngarugikeun industri telekomunikasi trilyunan dolar. ''Penyadap''Panyadap nu teu jujur ieu kalayan ngagunakeun alat husus bisa nguping (nyadap) nomer seri éléktronik ([[ESN]]) dina jero ''handset''. ESN téh ngarupakeun pakét data nu dikirim ku ''handset'' ka koropak langganan dina sistem sélulér nu dimaksudkeun pikeun ngumpulkeun data tagihan. Sistem sélulér satuluyna ngabeunangkeun atawa ngalarang pamaké ''handset'' pikeun nelepon atawa ngagunakeun fitur tinangtu dumasar kana koropak langganan kasebut. Lamun ESN disadap, mangka nomer kasebut bisa ditiron (di-cloning) ku telepon lianna sarta digunakeun di daérah lian pikeun nelepon tanpa mayar. Sanajan ''cloning'' masih bisa dilakukeun kiwari dina jaman téknologi digital, saeutik pisan untungna sahingga masalah ieu leungit sorangan. Kiwari AMPS geus kasilih ku standar digital nu leuwih anyar saperti [[D-AMPS]], [[GSM]], jeung [[CDMA2000]] nu nawarkeun kaamanan nu leuwih hadé sarta kamampuh nu leuwih gedé.
 
==Pita frékuénsi==
 
Layanan telekomunikasi sélulér AMPS dijalankeun dina pita frékuénsi 800 [[MHz]]. Anatomi unggal kanal diwangun ku dua [[frékuénsi]], nyaéta frékuénsi ''[[downlink]]'' ti [[base station]] jeung frékuénsi ''[[uplink]]'' ti ''handset''. 416 frékuénsi ''uplink'' dina pita 824–849&nbsp;MHz digunakeun pikeun ngirimkeun sora ti ''handset'' ka [[base station]], papasangan jeung 416 frékuénsi ''downlink'' dina pita 869–894&nbsp;MHz pikeun ngirimkeun sora ti [[base stations]] ka ''handset''. Unggal situs sél (base station) baris ngagunakeun sabagéan tina kanal-kanal ieu, sarta kudu béda jeung situs sél sabudeureunana pikeun nyingkahan gangguan ([[interférensi]]). Hal ieu anu ngabalukarkeun jadi kurangna jumlah kanal dina unggal situs sél. Unggal kanal AMPS rubakna 30&nbsp;kHz.
{{tarjamahkeun|Inggris}}
AMPS cellular service operates in the 800 [[MHz]] [[Cellular frequencies|Cellular]] [[FM]] band. For each market area, the United States [[Federal Communications Commission]] (FCC) allowed two licensee (networks) known as "A" and "B" carriers. Each carrier within a market uses a specified "block" of frequencies consisting of 21 control channels and 395 voice channels. Originally, the B (wireline) side license was usually owned by the local phone company such as a "Baby Bell" (Ameritech), and the A (non-wireline) license was made available to private companies such as Cellular One. At the inception of cellular in 1983, the FCC had granted each carrier within a market 333 channels (666 channels total). By the late 1980s, the cellular industry's subscriber base had grown into the millions across America and it became necessary to add channels for additional capacity. In 1989, the FCC granted carriers an expansion from the current 666 channels to the now 832 (416 per carrier). The additional frequency was available in the upper 800&nbsp;MHz band which also was home to UHF channels 70–83. This meant that these UHF channels could no longer be used for UHF TV transmission as these frequencies were to be used for AMPS transmission.
 
The anatomy of each channel is composed of 2 [[frequency|frequencies]]. 416 of these are in the 824–849&nbsp;MHz range for transmissions from mobile stations to the base stations, paired with 416 frequencies in the 869–894&nbsp;MHz range for transmissions from base stations to the mobile stations. Each cell site will use a subset of these channels, and must use a different set than neighboring cells to avoid interference. This significantly reduces the number of channels available at each site in real-world systems. Each AMPS channel is 30&nbsp;kHz wide.
 
==AMPS analog diganti ku nu digital==
 
Lantaran téknologi AMPS téh standarna analog, mangka ieu téknologi henteu éfisien dina ngagunakeun spéktrum frékuénsi. Kiwari, ampir kabéh pausahaan telekomunikasi pamaké AMPS geus ngaganti téknologina ku nu boga standar-standar digital saperti CDMA2000 atawa GSM. Téknologi digital saperti GSM jeung CDMA2000 nawarkeun kamampuh ngirimkeun réa sora dina hiji kanal jeung fitur mutahir saperti pangiriman pesen dua arah (''two-way text messaging'') jeung layanan data. [[Bell Mobility]] jeung [[Telus Mobility]] di [[Kanada]], anu can ngabongkar jaringan AMPS bogana nepi ka bulan Pebruari 2008 téh.[http://www.sptnews.ca/index.php?option=com_content&task=view&id=238&Itemid=9]. [[OnStar]] masih gumantung pisan kana layanan AMPS di Amérika Kalér. Sanajan kitu, ieu pausahaan kiwari keur migrasi kana sistem digital. [[ADT Security Services]] kiwari malah ménta [[FCC]], regulator telekomunikasi di Amérika Sarikat, sangkan manjangkeun wates waktu pikeun nutup izin AMPS lantaran loba pisan sistem alarem bogana nu ngagunakeun téknologi analog pikeun komunikasi jeung puseur kadalina.<ref name = "ITWorld">[http://wireless.itworld.com/4279/061004adt/page_1.html ITWorld].</ref>
In 2002, the FCC decided to no longer require A and B carriers to support AMPS service as of [[February 18]], [[2008]]. Since the AMPS standard is analog technology, it suffers from an inherently inefficient use of the frequency spectrum. All AMPS carriers have converted most of their consumer base to a digital standard such as CDMA2000 or GSM and continue to do so at a rapid pace. Digital technologies such as GSM and CDMA2000 support multiple voice calls on the same channel and offer enhanced features such as two-way text messaging and data services.
 
Unlike in the United States, the [[Canadian Radio-television and Telecommunications Commission]] (CRTC) and [[Industry Canada]] have not set any requirement for maintaining AMPS service in Canada. [[Rogers Wireless]] has dismantled their AMPS (along with [[IS-136]]) network, the networks were shut down [[May 31]], [[2007]]. [[Bell Mobility]] and [[Telus Mobility]], operate AMPS networks in Canada, they have announced that they will observe the same timetable as outlined by the FCC in the United States, and as a result will not begin to dismantle their AMPS networks until after February 2008.[http://www.sptnews.ca/index.php?option=com_content&task=view&id=238&Itemid=9]
 
[[OnStar]] relies heavily on North American AMPS service for its subscribers because, when the system was developed, AMPS offered the most comprehensive wireless coverage in the US. [[ADT Security Services|ADT]] recently asked the FCC to extend the AMPS deadline due to many of their alarm systems still using analog technology to communicate with the control centers.<ref name = "ITWorld">[http://wireless.itworld.com/4279/061004adt/page_1.html ITWorld].</ref> Cellular companies who own an A or B license (such as Verizon and Alltel) must still provide analog service until [[February 18]], [[2008]]. After that point, however, most cellular companies will be eager to shut down AMPS and use the remaining channels for digital services. [[OnStar]] is transitioning to digital service with the help of data transport technology developed by Airbiquity, but warns customers who cannot be upgraded to digital that their service will permanently expire on [[January 1]], [[2008]].<ref name = "OnStar">[http://www.onstar.com/us_english/jsp/explore/onstar_basics/helpful_info.jsp?info-view=tech_equip OnStar].</ref>
 
==Rujukan==