FAQ
Q-01 > What does 3G stands for?
Q-02 > Why do we need 3G?
Q-03 > What is the difference between 3G and 2.5G?
Q-04 > What does the acronym UMTS stand for?
Q-05 > What is UMTS?
Q-06 > What are the different types of 3G networks?
Q-07 > What are the different types of 3G core networks?
Q-08 > What is the difference between cdma2000 and UMTS?
Q-09 > What are 1G, 2G, 2.5G, 3G and 4G?
Q-10 > Why is WCDMA called "Wideband"?
Q-11 > What is the 3G status in the USA?
Q-12 > What is the 3G status in the China?
Q-13 > Which network vendors can build a turn key 3G network?
Q-14 > Who much does 3G network cost to build?
Q-15 > Will the future 3G handsets be compatible with 2G systems and PCs?
Q-16 > How many Base Stations are needed for an UMTS network?
Q-17 > What are the UMTS data rates of the services?
Q-18 > Which modulation scheme is being used in UMTS
Q-19 > What services are enabled by 3GSM systems?
Q-20 > Are 3GSM systems truly global?
Q-21 > Can I receive 3GSM services from my current mobile handset?
Q-22 > What's next for 3GSM?
Q-01 > What does 3G stands for?
3G stands for Third Generation mobile communication networks. It is a successor to 2G and 2.5G networks.
Q-02 > Why do we need 3G?
In the early 1990s, before the commercial success of GSM and other second generation (2G) mobile networks, it was felt that the existing standards were inadequate in terms of bandwidth and service capabilities. Thus, research work was started by various organizations to move towards the next generation mobile network. Since the main bottleneck to providing greater bandwidth was the “air interface", much of the research focus was on this area. Five different radio interface systems were proposed by various standardization bodies. The International Telecommunication Union wanted a single radio interface that would provide global roaming. However, due to various technical and other reasons, a set of five standards was adopted for the radio interface of the Third Generation (3G) mobile networks.
Q-03 > What is the difference between 3G and 2.5G?
The term 3G refers to the next generation of wireless communications technology, the "first generation" having been analogue cellular, and the "second generation" (2g and 2.5G) being today's existing GSM/GPRS networks. 3G aims to provide universal, high-speed, high bandwidth support to bandwidth hungry applications such as full motion videos, video calling and full Internet access.
Q-04 > What does the acronym UMTS stand for?
UMTS stands for Universal Mobile Telephone System.
Q-05 > What is UMTS?
UMTS is one of the Third Generation (3G) mobile systems being developed within the ITU's IMT-2000 framework. It is a realisation of a new generation of broadband multi-media mobile telecommunications technology. The coverage area of service provision is to be world wide in the form of FLMTS (Future Land Mobile Telecommunications Services and now called IMT2000). The coverage will be provided by a combination of cell sizes ranging from 'in building' Pico Cells to Global Cells provided by satellite, giving service to the remote regions of the world. The UMTS is not a replacement of 2nd generation technologies (e.g. GSM, DCS1800, CDMA, DECT etc.), which will continue to evolve to their full potential.
Q-06 > What are the different types of 3G networks?
ITU Recommendation ITU-R M.1457 specifies five types of 3G radio interfaces:
- IMT-2000 CDMA Direct Spread, also known as UTRA FDD including WCDMA in Japan, ARIB / DoCoMo recommendation. UMTS is developed by 3GPP.
- IMT-2000 CDMA Multi-carrier, also known as Cdma2000 (3X) developed by 3GPP2. IMT-2000 CDMA2000 includes 1X components, like cdma2000 1X EV-DO.
- IMT-2000 CDMA TDD, also known as UTRA TDD and TD-SCDMA. TD-SCDMA is developed in China and supported by TD-SCDMA Forum
- IMT-2000 TDMA Single Carrier, also known as UWC-136 (Edge) supported by UWCC
- IMT-2000 DECT supported by DECT Forum.
Some 2.5G systems (GSM GPRS, IS- 95B and CDMA2000 1X (?)) will be able to deliver 3G services, so it will be difficult for users to see the difference.
Q-07 > What are the different types of 3G core networks?
The IMT-2000 family of 3G systems includes three types of Core Network technology:
- GSM based (using Mobile Application Part (MAP) protocols on top of SS7 protocols for signaling)
- ANSI-41 based (IS-634 protocols for signaling)
- Internet Protocol based (in future, to be specified)
Q-08 > What is the difference between cdma2000 and UMTS?
Cdma2000 and UMTS were developed separately and are 2 separate ITU approved 3G standards. Cdma2000 1xRTT, cdma2000 1xEV-DO (EVolution, Data Only) and future cdma2000 3x were developed to be backward compatible with cdmaOne. Both 1x types have the same bandwidth, chip rate and it can be used in any existing cdmaOne frequency band and network. Backward compatibility was a requirement for successful deployment for USA market. It is easy to implement because operators do not need new frequencies.
UMTS was developed mainly for countries with GSM networks, because these countries have agreed to free new frequency ranges for UMTS networks. Because it is a new technology and in a new frequency band, whole new radio access network has to be build. The advantage is that new frequency range gives plenty of new capacity for operators. 3GPP is overseeing the standard development and has wisely kept the core network as close to GSM core network as possible. UMTS phones are not meant to be backward compatible with GSM systems. (but subscriptions (=SIM card) can be, and dual mode phone will solve the compatibility problems, hopefully). UMTS also has 2 flavors FDD (will be implemented first) and TDD.
Some harmonization has been done between systems (like chip rate and pilot issues)
Q-09 > What are 1G, 2G, 2.5G, 3G and 4G?
Technically generations are defined:
- 1G networks (NMT, C-Nets, AMPS, TACS) are considered to be the first analog cellular systems, which started early 1980s. There were radio telephone systems even before that.
- 2G networks (GSM, cdmaOne, DAMPS) are the first digital cellular systems launched early 1990s.
- 2.5G networks (GPRS, cdma2000 1x) are the enhanced versions of 2G networks with data rates up to about 144kbit/s.
- 3G networks (UMTS FDD and TDD, cdma2000 1x EVDO, cdma2000 3x, TD-SCDMA, Arib WCDMA, EDGE, IMT-2000 DECT) are the latest cellular networks that have data rates 384kbit/s and more.
- 4G is mainly a marketing buzzword at the moment. Some basic 4G research is being done, but no frequencies have been allocated. The Forth Generation could be ready for implementation around 2012.
Q-10 > Why is WCDMA called "Wideband"?
3G WCDMA systems have 5MHz bandwidth (one direction). 5MHz is neither wide nor narrow; it is just the bandwidth. New 3G WCDMA systems have wider bandwidth than existing 2G cdma systems (cdmaOne 1.25MHz), that's why the "Wide". There are commercial cdma systems with 20MHz bandwidth.
Q-11 > What is the 3G status in the USA?
ome operators have taken the path cdmaOne - cdma2000 1x - cdma2000 1x EV-DO - cdma2000 3x some D-AMPD - EDGE and some have chosen a GSM1900 - EDGE ( - possible UMTS) route. New cellular frequencies allocations have been postponed, so operators will have to use their existing frequencies, which naturally limits the available capacity.
Q-12 > What is the 3G status in the China?
ome operators have taken the path cdmaOne - cdma2000 1x - cdma2000 1x EV-DO - cdma2000 3x some D-AMPD - EDGE and some have chosen a GSM1900 - EDGE ( - possible UMTS) route. New cellular frequencies allocations have been postponed, so operators will have to use their existing frequencies, which naturally limits the available capacity.
Q-13 > Which network vendors can build a turn key 3G network?
No network vendor can supply all equipment and components to the full a 3G network, but quite a few can be a main contractor to build a turn-key 3G network. Normally network vendors can bring in partners like service and applications providers, hand set manufactures, civil work and acquisition companies etc.
Current short list of main vendors for turn-key UMTS networks:
- Alcatel
- Ericsson
- Lucent
- Motorola
- Nokia
- Nortel
- Siemens/NEC
Current short list of main vendors for turn-key cdma2000 networks:
- Ericsson
- LG Electronics
- Lucent
- Motorola
- Nortel
- Samsung
Q-14 > Who much does 3G network cost to build?
Good source of information is to contract announcements and annual reports. Those usually tell how much money an operator will spend on infrastructure. In every country each carrier has to spend around same amount of money to build a same size 3G network, so if you see one of the operator's spending figures, all other operators use similar sums of money per subscriber.
Sometimes spending figures include services (planning, logistics, commissioning, integration, testing etc.), but almost never civil works on base station sites. Press reports claim that operators in Europe have spend around 650 euro per 3G subscriber for infrastructure + planning services + site civil works, this figure should drop to around 400 euros within couple of years.
Infrastructure cost are only small part of total network related cost and operators also have license fees, financing fees, cost of running the organization, sales and marketing costs etc.
Q-15 > Will the future 3G handsets be compatible with 2G systems and PCs?
Some of the 3G mobiles will be dualband UMTS/GSM handsets (available late 2002?) and will be able to perform UMTS-GSM handovers. Current GSM phones will not work in 3G networks. Several SIM card manufacturers now offer cards compatible with 2G and 3G systems. Cellular3G, for example, will offer PCMCIA W-CDMA 3G-modem cards for PCs.
3G cdma2000 phones will be backward compatible and will work in cdmaOne networks. Air prime, for example, offers CDMA2000 1xEV-DO PC cards for 3G networks.
Q-16 > How many Base Stations are needed for an UMTS network?
There are several factors:
- Required coverage areas according to a license agreement (link budget will determine the cell spacing)
- Required capacity according to license agreement and initial customer and operator demands
- Amount of frequencies carries have. (More frequencies, less interference, longer cell spacing)
- Ability to get BTS site locations. (Normally co-location requirements with used 2G sites)
- Financing available for network build.
- Economical factor to build sites.
- Design opinions and experience of companies and people bidding for the design job and eventually implementing the plan.
- And probably in a long run the capacity, service, and coverage requirement from customers.
Rollout will be very similar to 2G network rollouts. First phase of rollouts in UK size market will probably be 1000 base station in urban areas. Within 5 year about site count will increase to 5000 sites and eventually up to 10000 sites depending how successful the business is.
Q-17 > What are the UMTS data rates of the services?
2.048Mb/s for pico-cell (and micro-cell) applications.
384kb/s for medium size cells. (micro and small macro cells)
144kb/s and 64kb/s for large cell applications. (Large macro cells)
14.4kb/s for continuous low speed data applications in very large cells.
12.2kb/s for speech (4.75kb/s - 12.2kb/s), 9.6kb/s globally (satellite).
Q-18 > Which modulation scheme is being used in UMTS
MTS WCDMA modulation is Quadrature Phase Shift Keying (QPSK) with Root-raised cosine pulse shaping filters (roll off = 0.22)
Q-19 > What services are enabled by 3GSM systems?
TV and video on demand, high-speed multimedia data services and mobile Internet access are just a few of the offerings available to users. 3GSM expands the potential for content-rich information and communication services, as well as providing enhanced capacity for traditional voice services. 3GSM bridges the gap between the wireless world and the computing/Internet world, creating the possibility of seamless inter-operation between the two.
Q-20 > Are 3GSM systems truly global?
One of the most important characteristics of 3GSM is that it has been developed to be backward compatible with GSM systems, which have been deployed by 680 operators in more than 200 countries and territories. This interoperability of systems and services will ensure the continuation of the worldwide roaming experience users have enjoyed with GSM.
Q-21 > Can I receive 3GSM services from my current mobile handset?
3GSM is a new technology and therefore you will not be able to access 3GSM multimedia services using your existing GSM handset. It is up to you to choose whether you want to use the 3GSM services, and you will need to upgrade your mobile to be able to use these services. However, 3GSM has been designed to be backward compatible which means that you can continue to enjoy the voice and data services delivered by GSM from a 3GSM handset, while experiencing 3GSM services where they are available. You can also continue to enjoy voice and data services using a standard GSM phone in a 3GSM network coverage area.
Q-22 > What's next for 3GSM?
The next step in the GSM Association's roadmap for future services is downlink performance improvement - High Speed Downlink Packet Access (HSDPA). HSDPA will offer operator’s higher data transfer speeds and greater system capacity that, in turn, will enhance their ability to provide mobile broadband multimedia services. It will also tap the generic benefits of GSM such as global roaming, seamless billing, network compatibility and huge economies of scale.