3G (dibaca: triji, asalna tina kecap-kecap basa Inggris 3rd Generation) nyaéta standar katut téknologi telepon sélulér generasi-katilu, anu hadir saenggeus lahirna 2G. 3G téh dijieun dumasar kana kulawarga standar anu dikaluarkeun ku International Telecommunication Union (ITU) hasil tina kagiatan International Mobile Telecommunications programme, "IMT-2000". Téknologi 3G ngamungkinkeun operator jaringan pikeun nawarkeun ka palangganna rupa-rupa layanan anu leuwih canggih bari ngahasilkeun kapasitas jaringan anu leuwih gédé ku cara ningkatkeun éfisiénsi spéktrum frékuénsi. Layanan-layanan ieu di antarana wide-area wireless voice telephony jeung broadband wireless data, anu dijalankeun dina lingkungan bagerak (usik).  Biasana, 3G nawarkeun layanan anu laju pangiriman datana 5-10 Mb per detik.

Henteu jiga jaringan IEEE 802.11, jaringan 3G mah mangrupa jaringan telepon sélulér anu ngawengku daérah anu lega sarta mampuh nyadiakeun aksés internét jeung telepon vidéo dina laju pangiriman data nu gancang. Sedengkeun jaringan IEEE 802.11 (Wi-Fi)  mah mangrupa jaringan pitarubak anu wewengkonna leutik (radius pancaranana pondok) sarta dimekarkeun utamana pikeun ngirim data.

Nurutkeun Global mobile Suppliers Association, dina bulan Désémber 2005, 100 jaringan 3G dijalankeun di 40 nagara. Di Asia, Éropah, Kanada jeung Amérika Sarikat, pausahaan-pausahaan télékomunikasi ngagunakeun téknologi W-CDMA anu narima kira-kira 100 désain terminal pikeun ngajalankeun jaringan sélulér 3G.

 Sajarah 
 
Di Éropah, layanan 3G munggaran ditawarkeun di Inggris jeung Italia dina bulan Maret 2003. Harita Déwan Uni Éropah ngusulkeun yén para operator 3G kudu ngalayanan 80% populasi nasional masing-masing nagara anggota dina tungtung taun 2005.

Pangwangunan jaringan 3G ditanggohkeun di sabagian nagara di dunya lantaran biaya idin spéktrum frékuénsi anu mahal. Baca ogé Telecoms crash.  Di réa nagara, jaringan 3G henteu ngagunakeun frékuénsi radio anu sarua jeung 2G, antukna para operator kudu ngawangun jaringan anu samasakali anyar sarta merlukeun idin guna frékuénsi anu ogé anyar; anu mahiwal mah kajadian di Amérika Sarikat di mana para operator ngajalankeun layanan 3G dina frékuénsi anu sarua jeung layanan sélulér lianna. Sedengkeun di Éropah, biaya idin di sabagian nagara anggota mahal pisan. Alesan lain nu ngabalukarkeun pananggohan layanan 3G nyaéta waragad pikeun ningkatkeun kamampuh alat-alat nu aya supaya jadi sistem anu anyar.

Nepi ka bulan Juni 2007, aya 200 juta langganan anu geus kasambungkeun kana layanan 3G. Dibandingkeun jeung palanggan telepon sélulér sadunya anu jumlahna 3 triliun, angka éta ngan 6.7%. Di nagara-nagara tempat 3G munggaran disadiakeun – Jepang jeung Koréa Kidul – leuwih ti satengah langganan telepon sélulér ngagunakeun 3G. Di Éropah, Italia mangrupa nagara anu rahayatna panglobana ngagunakeun layanan 3G; sapertilu jumlah langganan telepon sélulérna pindah ngagunakeun éta layanan. Nagara lianna anu mingpin dina migrasi ka 3G di antarana Inggris, Austria jeung Singapura anu ngahontal angka 20% tina jumlah langganan telepon sélulér.

EMTEL Ltd, pausahaan télékomunikasi sélulér kadua panggedéna di Mauritius, geus ngamparkeun jaringan 3G UMTS komérsial munggaran di Afrika (percobaan telepon munggaran dilakukeun dina tanggal 16 Oktober 2004). Layanan komérsial anu sapinuhna mitembeyan dina bulan Nopémber 2004, anu ngajadikeun jaringan 3G boga ieu pausahaan sabagé jaringan 3G komérsial munggaran di Afrika. Di Afrika beulah kalér, Wana di Moroko nyadiakeun layanan 3G dina ahir Maret 2006. Operator lianna di éta nagara ngamimitian ngajalankeun jaringan 3G dina patengahan taun 2007. Vodafone Mesir (anu katelah ogé CLICK GSM) nyadiakeun layanan 3G dina patengahan taun 2006.  Dina awal taun 2007, Vodacom Tanzania mimiti migrasi kana sistem 3G High-Speed Downlink Packet Access (HSDPA) di Dar Es Salaam.  Tanzania mangrupa nagara kadua di Afrika anu ngagunakeun téknologi kasebut saenggeus Afrika Kidul. Dina bulan Maret 2007, Nigeria méré idin 3G ka tilu pausahaan GSM panggedéna sarta ka hiji pausahaan anu teu kasohor, Alheri Engineering Co. Ltd, pikeun ngaréaan rupa layananana.

Rogers Wireless mimiti nawarkeun layanan 3G HSDPA di Kanada Beulah wétan dina awal taun 2007.

 Kaistiméwaan 

Kaistiméwaan téknologi sélulér 3G nyaéta ieu téknologi téh bisa narima jumlah palanggan anu leuwih réa. – hususna di daérah pakotaan – sarta laju data anu leuwih gancang kalawan waragad pangwangunan anu leuwih murah manan 2G.

3G ngagunakeun pamawa sinyal kalayan kanal anu rubakna 0,6 MHz pikeun ngirimkeun data dina laju anu jauh leuwih gancang sarta kapasitas anu jauh leuwih gedé batan jaringan 2G.

Pamawa sinyal anu kanalna 0.5 MHz ngoptimalkeun pamakéan sumber daya frékuénsi radio pikeun para operator anu geus dibéré loba lahan (blok) spéktrum frékuénsi nu paréndéng. Sajaba ti éta, hal ieu ogé ngabantu pikeun ngurangan waragad nu dibutuhkeun sarta mampuh nyadiakeun pangiriman data kalayan laju anu kacida gancangna pikeun langganan.

Ieu téknologi ogé ngamungkinkeun pangiriman data dina laju 384 kbit/det pikeun sistem anu bagerak (usik) sarta 2 Mb/s pikeun sistem anu cicing. Para pamaké layanan 3G dibéré harepan bisa ngarasakeun kapasita anu leuwih gedé sarta éfisiénsi spéktrum anu leuwih alus, anu ngamungkinkeun roaming ti hiji jaringan 3G ka jaringan 3G lianna.

 Standar 

International Telecommunications Union (ITU):
IMT-2000 kawangun ku genep antarmuka radio:

 W-CDMA
 CDMA2000
 TD-CDMA / TD-SCDMA
 UWC (mindeng diwangun bareng jeung EDGE)
 DECT
 Mobile WiMAX 

 Evolution to 3G 

Cellular mobile telecommunications networks are being upgraded to use 3G technologies from 1999 to 2010. Japan was the first country to introduce 3G nationally, and in Japan the transition to 3G was largely completed in 2006. Koréa then adopted 3G Networks soon after and the transition was made as éarly as 2004.
 Operators and UMTS networks 

As of 2005, the evolution of the 3G networks was on its way for a couple of yéars, due to the limited capacity of the existing 2G networks. 2G networks were built mainly for voice data and slow transmission. Due to rapid changes in user expectation, they do not meet today's wireless needs.

"2.5G" (and even 2.75G) are technologies such as i-mode data services, camera phones, high-speed circuit-switched data (HSCSD) and General packet radio service (GPRS) were créated to provide some functionality domains like 3G networks, but without the full transition to 3G network. They were built to introduce the possibilities of wireless application technology to the end consumers, and so incréase demand for 3G services.

 Network standardization 
The International Telecommunication Union (ITU) defined the demands for 3G mobile networks with the IMT-2000 standard. An organization called 3rd Generation Partnership Project (3GPP) has continued that work by defining a mobile system that fulfills the IMT-2000 standard. This system is called Universal Mobile Telecommunications System (UMTS).

The evolution of the system will move forward with so called reléases. éach reléase will introduce new féatures. The following féatures are examples of many others in these new reléases.

 Release '99 
 Béarer services
 64 kbit/s circuit switched
 384 kbit/s packet switched
 Location services
 Call services: compatible with Global System for Mobile Communications (GSM), based on Universal Subscriber Identity Module (USIM)

 Release 4 
 Edge radio
 Multimedia messaging
 MeXe levels
 Improved location services
 IP Multimedia Services (IMS)

 Release 5 
 IP Multimedia Subsystem (IMS)
 IPv6, IP transport in UTRAN
 Improvements in GERAN, Mexe, etc
 HSDPA

 Release 6 
 WLAN integration
 Multimedia broadcast and multicast
 Improvements in IMS
 HSUPA

 3G evolution (pre-4G) 
 The standardization of 3G evolution is working in both 3GPP and 3GPP2. The corresponding specifications of 3GPP and 3GPP2 evolutions are named as LTE and UMB, respectively. 3G evolution uses partly beyond 3G technologies to enhance the performance and to maké a smooth migration path.

There are several different paths from 2G to 3G. In Europe the main path starts from GSM when GPRS is added to a system. From this point it is possible to go to the UMTS system. In North America the system evolution will start from Time division multiple access (TDMA), change to Enhanced Data Rates for GSM Evolution (EDGE) and then to UMTS.

In Japan, two 3G standards are used: W-CDMA (compatible with UMTS) used by NTT DoCoMo and Softbank, and CDMA2000, used by KDDI. Transition to 3G was completed in Japan in 2006.

 Advantages of a layered network architecture 
Unlike GSM, UMTS is based on layered services. At the top is the services layer, which provides fast deployment of services and centralized location. In the middle is the control layer, which helps upgrading procedures and allows the capacity of the network to be dynamically allocated. At the bottom is the connectivity layer where any transmission technology can be used and the voice traffic will transfer over ATM/AAL2 or IP/RTP.

 Mobile technologies 
When converting a GSM network to a UMTS network, the first new technology is General Packet Radio Service (GPRS). It is the trigger to 3G services. The network connection is always on, so the subscriber is online all the time. From the operator's point of view, it is important that GPRS investments are re-used when going to UMTS. Also capitalizing on GPRS business experience is very important.

From GPRS, operators could change the network directly to UMTS, or invest in an EDGE system. One advantage of EDGE over UMTS is that it requires no new licenses. The frequencies are also re-used and no new antennas are needed.

 From GPRS to UMTS 
 Home location régister (HLR)
 Visitor location régister (VLR)
 Equipment identity régister (EIR)

From GPRS network, the following network elements can be reused:
 Mobile switching centre (MSC) (vendor dependent)
 Authentication centre (AUC)
 Serving GPRS Support Node (SGSN) (vendor dependent)
 Gateway GPRS Support Node (GGSN)

From Global Service for Mobile (GSM) communication radio network, the following elements cannot be reused
 Base station controller (BSC)
 Base transceiver station (BTS)
They can remain in the network and be used in dual network operation where 2G and 3G networks co-exist while network migration and new 3G terminals become available for use in the network.

The UMTS network introduces new network elements that function as specified by 3GPP:
 Node-B (base station)
 Radio Network Controller (RNC)
 Media Gateway (MGW)

The functionality of MSC and SGSN changes when going to UMTS. In a GSM system the MSC handles all the circuit switched operations like connecting A- and B-subscriber through the network. SGSN handles all the packet switched operations and transfers all the data in the network. In UMTS the Media gateway (MGW) take care of all data transfer in both circuit and packet switched networks. MSC and SGSN control MGW operations. The nodes are renamed to MSC-server and GSN-server.

 UMTS and 3G terminals 

3G handsets usually have cameras, music players, video players, contactless smartcards for payment functions (wallet phones), Web browsers, email clients and more. This shows that the UMTS system is based on layered services and future applications can be supported without too much impact to the underlying radio access network.

 UMTS terminals 
The technical complexities of a 3G phone or handset depends on its need to roam onto legacy 2G networks. In the first countries, Japan and South Koréa, there was no need to include roaming capabilities to older networks such as GSM, so 3G phones were small and lightweight. In Europe and America, the manufacturers and network operators wanted multi-mode 3G phones which would operate on 3G and 2G networks (e.g., WCDMA and GSM), which added to the complexity, size, weight, and cost of the handset. As a result, éarly Européan WCDMA phones were significantly larger and héavier than comparable Japanese WCDMA phones.

Japan's Vodafone KK experienced a gréat déal of trouble with these differences when its UK-based parent, Vodafone, insisted the Japanese subsidiary use standard Vodafone handsets. Japanese customers who were accustomed to smaller handsets were suddenly required to switch to Européan handsets that were much bulkier and considered unfashionable by Japanese consumers. During this conversion, Vodafone KK lost 6 customers for every 4 that migrated to 3G. Soon theréafter, Vodafone sold the subsidiary (now known as Softbank).

The general trend to smaller and smaller phones seems to have paused, perhaps even turned, with the capability of large-screen phones (similar to the Apple iPhone - interestingly EDGE, not 3G) to provide more vidéo, gaming and internet use on the 3G networks.

 Issues 
Although 3G was successfully introduced to users in Europe, Asia, South America, North America (U.S.A.) and Africa, some issues are debated by 3G providers and users:
 Expensive input fees for the 3G service licenses
 Numerous differences in the licensing terms
 Large amount of debt currently sustained by many telecommunication companies, which makes it a challenge to build the necessary infrastructure for 3G
 Lack of member state support for financially troubled operators
 Expense of 3G phones
 Lack of buy-in by 2G mobile users for the new 3G wireless services
 Lack of coverage, because it is still a new service
 High prices of 3G mobile services in some countries, including Internet access (see flat rate)
 Current lack of user need for 3G voice and data services in a hand-held device
 High power usage

 See also 
 2G
 2.5G
 2.75G
 3.5G
 3.75G
 4G
 3GP 3G multimedia container format (mobile vidéo)
 IP Multimedia Subsystem
 WiBro
 WiMAX
 Wireless modem
 Spectral efficiency comparison table
 DigRF V3'

References

Tumbu kaluar 
 Get Schooled - What's Driving 3G Evolution? * TeleDict Blog
 3G Internet Business Back-up

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