TD-SCDMA

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Standar
telepon mobil jeung data
Kulawarga GSM / UMTS
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3G
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Kulawarga cdmaOne / CDMA2000
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3G
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Tehnologi sejen
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Pita frékuénsi

TD-SCDMA (singketan tina kecap-kecap basa Inggris "Time Division-Synchronous Code Division Multiple Access") nyaéta salasahiji standar telekomunikasi mobil 3G, anu keur digawékeun di Republik Rakyat Cina ku Chinese Academy of Telecommunications Technology (CATT), Datang sarta Siemens AG, dina raraga supaya henteu gumantung kana téknologi urang Barat [1]. Alesan utama dijieunna ieu standar cenah format 3G lianna nyaratkeun bayaran béa patén ka sajumlah urang Barat anu mibanda hak patén[2]. TD-SCDMA didasarkeun kana téknologi spéktrum sebar sarta kamunginan bakal bébas tina kawajiban mayar patén ka urang Barat.

Pamasangan jeung pamakéan jaringan[édit | sunting sumber]

Dina tanggal 20 Januari 2006, Mantri Industri Informasi Républik Rakyat Cina sacara resmi ngumumkeun yén TD-SCDMA ngarupakeun standar boga nagara kasebut pikeun telekomunikasi mobil 3G. Dina tanggal 15 Pébruari 2006, pamaréntah Cina ngumumkeun jadwal waktu pikeun pamasangan jaringan TD-SCDMA di Cina, sarta ngémbarkeun uji coba pra komérsial dimimitian saenggeus réngséna sajumlah uji jaringan di sababaraha kota anu dipilih. Uji coba ieu dilaksanakeun ti bulan Maret nepi ka bulan Oktober 2006, tapi hasilna teu nyugemakeun. Pangwangunan jaringan-jaringan nu ngagunakeun standar 3G lianna (WCDMA katut CDMA2000 EV/DO) ditunda nepi ka siapna TD-SCDMA.

Standar kasebut geus diadopsi ku 3GPP. TD-CDMA (nu leuwih deukeut kana W-CDMA), ditawarkeun salaku air interfaces pikeun sistem UMTS-TDD, kaol UMTS anu kalolobaan digunakeun pikeun nyadiakeun aksés Internét. Pamakéan TDD leuwih éfisién batan FDD pikeun laju data asimétrik, anu ilahar dina pamakéan Internét.

Panneau travaux.png Artikel ieu keur dikeureuyeuh, ditarjamahkeun tina basa Inggris.
Bantosanna diantos kanggo narjamahkeun.

Ringkesan teknis[édit | sunting sumber]

TD-SCDMA uses TDD, in contrast to the FDD scheme used by W-CDMA. By dynamically adjusting the number of timeslots used for downlink and uplink, the system can more easily accommodate asymmetric traffic with different data rate requirements on downlink and uplink than FDD schemes. Since it does not require paired spectrum for downlink and uplink, spectrum allocation flexibility is also increased. Also, using the same carrier frequency for uplink and downlink means that the channel condition is the same on both directions, and the base station can deduce the downlink channel information from uplink channel estimates, which is helpful to the application of beamforming techniques.

TD-SCDMA also uses TDMA in addition to the CDMA used in WCDMA. This reduces the number of users in each timeslot, which reduces the implementation complexity of multiuser detection and beamforming schemes, but the non-continuous transmission also reduces coverage (because of the higher peak power needed), mobility (because of lower power control frequency) and complicates radio resource management algorithms.

The "S" in TD-SCDMA stands for "synchronous", which means that uplink signals are synchronized at the base station receiver, achieved by continuous timing adjustments. This reduces the interference between users of the same timeslot using different codes by improving the orthogonality between the codes, therefore increasing system capacity, at the cost of some hardware complexity in achieving uplink synchronization.

Rujukan[édit | sunting sumber]

  1. [1]
  2. 3G Licensing introduces the W-CDMA Patent Licensing Programme at the "Low Cost 3G Devices" conference, London, 13 March 2007

Tempo ogé[édit | sunting sumber]

Tumbu kaluar[édit | sunting sumber]

-Citakan:Standard-stub

Patras Wireless Network 1.jpg