3G is the third generation of mobile phone standards and technology, after 2G. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications programme, "IMT-2000". 3G technologies enable network operators to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency. Services include wide-area wireless voice telephony and broadband wireless data, all in a mobile environment. Typically, they provide service at 5-10 Mb per second.
Unlike IEEE 802.11 networks, 3G networks are wide area cellular telephone networks which evolved to incorporate high-speed internet access and video telephony. IEEE 802.11 (common home Wi-Fi) networks are short range, high-bandwidth networks primarily developed for data.
In December 2005, 100 3G networks were operating in 40 countries, according to the Global mobile Suppliers Association. In Asia, Europe, Canada and the USA, telecommunication companies use W-CDMA technology with the support of around 100 terminal designs to operate 3G mobile networks.
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[edit] History
In Europe, 3G services were introduced starting in March 2003 in the UK and Italy. The European Union Council suggested that the 3G operators should cover 80% of the European national populations by the end of 2005.
Roll-out of 3G networks was delayed in some countries by the enormous costs of additional spectrum licensing fees. See Telecoms crash. In many countries, 3G networks do not use the same radio frequencies as 2G, so mobile operators must build entirely new networks and license entirely new frequencies; an exception is the United States where carriers operate 3G service in the same frequencies as other services. The license fees in some European countries were particularly high, bolstered by government auctions of a limited number of licenses and sealed bid auctions, and initial excitement over 3G's potential. Other delays were due to the expenses of upgrading equipment for the new systems.
By June 2007 the 200 millionth 3G subscriber had been connected. Out of 3 billion mobile phone subscriptions worldwide this is only 6.7%. In the countries where 3G was launched first - Japan and South Korea over half of all subscribers use 3G. In Europe the leading country is Italy with a third of its subscribers migrated to 3G. Other leading countries by 3G migration include UK, Austria and Singapore at the 20% migration level. A confusing statistic is counting CDMA 2000 1x RTT customers as if they were 3G customers. If using this oft-disputed definition, then the total 3G subscriber base would be 475 million at June 2007 and 15.8% of all subscribers worldwide.
EMTEL Ltd, the second largest mobile telecommunications company in Mauritius (next to state owned Cellplus), has established the first commercial Universal Mobile Telecommunications Standard (UMTS) 3G network in Africa (the first test call was made on 16 October 2004). Full commercial services began in November 2004, making this the first commercial African 3G network. In north Africa, the first service of 3G started in Morocco in late March 2006, provided by the new company Wana. The other operator in the country should start its network in mid-2007. Vodafone Egypt (also known as CLICK GSM) was to provide the service in Egypt in mid-2006. In early 2007, Vodacom Tanzania switched on its 3G High-Speed Downlink Packet Access (HSDPA) in Dar Es Salaam. It is the second country in Africa with such technology, after South Africa. In March 2007, Nigeria awarded 3G telecommunication licenses to its three major GSM companies and a relatively unknown operator, Alheri Engineering Co. Ltd, to allow them to expand their scope of operation in the industry.
Rogers Wireless began implementing 3G HSDPA services in eastern Canada early 2007 in the form of Rogers Vision; expansion into western Canada is expected soon.
[edit] Features
The most significant feature of 3G mobile technology is that it supports greater numbers of voice and data customers — especially in urban areas — and higher data rates at lower incremental cost than 2G.
By using the radio spectrum in bands identified, which is provided by the UTI for Third Generation IMT-2000 mobile services, it subsequently licensed to operators. 3G uses .6 MHz channel carrier width to deliver significantly higher data rates and increased capacity compared to 2G networks.
The .5 MHz channel carrier provides optimum use of radio resources for operators who have been granted large, contiguous blocks of spectrum. On the other hand, it also helps to reduce the cost to 3G networks while being capable of providing extremely high-speed data transmission to users.
It also allows the transmission of 384 kbit/s for mobile systems and 2 Mb/s for stationary systems. 3G users are expected to have greater capacity and better spectrum efficiency, which allows them to access global roaming between different 3G networks.
[edit] Standards
International Telecommunications Union (ITU): IMT-2000 consists of six radio interfaces
[edit] 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. Korea became the first to adopt 3G Networks soon after and the transition was made as early as 2004, leading the world in communications.
[edit] Operators and UMTS networks
As of 2005, the evolution of the 3G networks was on its way for a couple of years, 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 created 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 increase demand for 3G services.
[edit] 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 releases. Each release will introduce new features. The following features are examples of many others in these new releases.
[edit] Release '99
- Bearer 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)
[edit] Release 4
- Edge radio
- Multimedia messaging
- MeXe levels
- Improved location services
- IP Multimedia Services (IMS)
[edit] Release 5
- IP Multimedia Subsystem (IMS)
- IPv6, IP transport in UTRAN
- Improvements in GERAN, Mexe, etc
- HSDPA
[edit] Release 6
[edit] 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 make 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.
[edit] 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.
[edit] 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.
[edit] From GPRS to UMTS
- Home location register (HLR)
- Visitor location register (VLR)
- Equipment identity register (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.
[edit] 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.
[edit] 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 Korea, 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, early European WCDMA phones were significantly larger and heavier than comparable Japanese WCDMA phones.
Japan's Vodafone KK experienced a great deal 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 European 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 thereafter, 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 video, gaming and internet use on the 3G networks.
[edit] Issues
Although 3G was successfully introduced to users in Europe, Asia, South America 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
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