Evolution to 3G
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The Evolution to 3G describes the updating of cellular mobile telecommunications networks around the world to use new 3G technologies. This process is taking place over the period 1999 to 2010. Japan is the first country having introduced 3G nationally, and in Japan the transition to 3G has been largely completed during 2005/2006. 3G technologies enable network operators to offer users a wider range of more advanced services, while achieving greater network capacity through improved spectral efficiency.
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[edit] Operators and UMTS networks
As of 2005, the evolution of the 3G networks was on its way for a couple of years. The main reason for these changes are basically the limited capacity of the existing 2G networks. The second generation of networks were built mainly for telephone calls and slow data transmission. Due to the rapid changes in technology, these factors do not meet the requirements of today's wireless revolution. The developments of so-called "2.5G" (or even 2.75G) technologies such as i-mode data services, camera phones, HSCSD and GPRS have been ways of bridging the oncoming change to 3G networks, but are not permanent solutions. They are merely stepping stones towards the new technology. These stepping stones were built to introduce the possibilities with the future wireless application technology to the end consumers. These procedures are necessary to ensure that the operators and the infrastructure itself have a healthy ground to operate on.
The evolution of networks from the second generation of technologies to the third generation technologies could not be done without the help of network operators. In 2005 there were about 23 networks worldwide that operated on 3G technologies, the most advanced being KDDI in Japan. Some of these networks were only for test use but some were already in consumer based use.
Basically network operators need to find the many answers to three questions before they can start operating in the new field. What are the things to take into consideration during the change? How to manage the change? What is the future role for the network operators?
Network operators have invested huge amounts of money into existing 2G networks. These networks have been around only for 10-15 years, and the investments made have not all paid off. Network operators need to find out ways of reusing their investments to build the 3G network. Because of the financial situation of the world, network operators do not necessarily have new resources to invest in the future. They must recycle the old ones first.
Another thing network operators need to understand is that their roles are changing dramatically. They are becoming not only network providers, but also service providers. Network operators need to differentiate themselves in the markets, and one way is to concentrate on the content of the service and products. It is widely believed that the markets will consist of content oriented service providers, since 3G technology allows anyone willing to build software and sell it directly to end consumers. Thus network operators need to adapt to this change too.
[edit] 2G to 3G Network standardisation
The International Telecommunication Union (ITU) has defined the demands for third generation mobile networks with the IMT-2000 standard. An organisation called 3GPP has continued that work by defining a mobile system that fulfils 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. In each release new features will be introduced. The following features are just 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: GSM-compatible, USIM-based
[edit] Release 4
- Edge radio
- Multimedia messaging
- MeXe levels
- Improved location services
[edit] Release 5
- IP Multimedia Subsystem (IMS)
- IPv6, IP transport in UTRAN
- Improvements in GERAN, Mexe, etc.
- HSDPA
[edit] Release 6
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 TDMA going to EDGE and from there to UMTS.
In Japan, there are two 3G standards used: W-CDMA (which is compatible with UMTS) by NTT DoCoMo, Vodafone KK, and by new entrants, and cdma2000 which is very successfully used by KDDI. Transition to 3G is being largely completed in Japan during 2005/2006.
[edit] Layered Network Architecture Advantages
The UMTS system is based on layered services, unlike GSM. On the top there is the services layer, which will give advantages like fast deployment of services and centralized location. In the middle there is the control layer, which will help upgrading procedures and allow the capacity of the network to be dynamically allocated. On 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
The first new technology when going from GSM towards UMTS is General Packet Radio Service (GPRS). It is the trigger to 3G services. The main point is that 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 go directly to UMTS, but they could also invest in an EDGE system. One advantage of EDGE is that there is no new licence needed as in UMTS. The frequencies will also be re-used and no new antennas are needed. The main issue is that subscribers will have to buy new EDGE terminals.
[edit] From GPRS to UMTS
The key point when going to UMTS is the use of the existing mobile network. From GSM core network side, the following network elements are reused:
- MSC (Mobile switching centre) (vendor dependent)
- AUC (Authentication centre)
- HLR (Home location register)
- VLR (Visitor location register)
- EIR (Equipment identity register)
From GPRS network, the following network elements will be reused:
- SGSN (Serving GPRS Support Node) (vendor dependent)
- GGSN (Gateway GPRS Support Node)
From GSM radio network, the following network elements can NOT be reused. Note, however 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.
- BSC (base station controller)
- BTS (base transceiver station)
The UMTS network introduces new network elements that give functionality as given in the 3GPP specifications:
- Node-B (base station)
- RNC (Radio Network Controller)
- MGW (Media Gateway)
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 MGW (Media gateway) will take care of all data transfer in both, circuit and packet switched networks. MSC and SGSN will act as "brains" of the system and they will control MGW operations. The name of the nodes will change into MSC-server and GSN-server.
[edit] Future network
When UMTS networks are in commercial use and the services have found users, we need to check whether the capacity given by UMTS is enough or do we need more capacity. To increase capacity WLAN could be one solution that would be cost-efficient. Integration with UMTS would not be so difficult to do. When so called "hot services" will be found in UMTS, we can see the demands for the network after UMTS. Before that it is hard to do any presumption how the network should evolve.
[edit] UMTS, 3G Terminals
3G handsets are far more advanced and have much more functionality than conventional 2G handsets. 3G handsets usually include cameras, music players, video players, contactless smartcards for payment functions (wallet phones), web browsers, email clients and more. This shows that 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 future
The future of UMTS terminals sees a change coming. So far the UMTS technology in Europe has primarily been used in very similar terminals as the GSM technology. The UMTS terminals have been very closely linked with GSM phones in Europe. This factor is now slowly starting to change - and has not been the case in Japan and South Korea, where 3G introduction is several years ahead of Europe.
