What are the Gs all about? Basically, these designations refer to different generations of mobile
telephone services, new ones which come along about every ten years. 3G, which is the one most widely used today, is the
International Telecommunication Union (ITU) standard for third generation mobile telephone systems
under the International Mobile Telecommunications programme, IMT-2000. Analog cellular was the
first generation, digital PCS was the second. Along with W-CDMA, 3G was the big rage in the
late 90's, with proponents announcing that it was the Killer Wireless Application because of its ability to simultaneously
transfer voice data (the phone call) and other non-voice data such as music, photographs, video, email,
instant messaging, and information downloads. 3G networks use a variety of wireless network technologies, including GSM,
CDMA, TDMA, WCDMA, CDMA2000, UMTS and EDGE, and this leads to some confusion as well as a great deal of flexibility.
3G implementation was slower than initially anticipated, however, because of the cost of upgrading equipment and
licensing fees for additional spectrum. The earlier, 2G networks didn't typically
use the same frequencies as 3G (except in the United States), and licensing fees, particularly in
Europe, were extremely expensive. Only Japan and South Korea were able to implement this technology
quickly, largely because of the high level of government support for new infrastructure advances. In
Japan, by the end of 2006 the majority of customers were on 3G and upgrades to the next stage,
3.5G (with 3 Mbit/s data rates), were underway. Implementation in the rest of the world is coming along,
but at a slightly slower pace. In December 2007, 190 3G networks were operating in 40 countries, with 200 million
subscribers, and those figures have increased since then -- but there are 3 billion mobile phone subscriptions worldwide
so we can expect to see different parts of the world operating on different standards for years to come.
You may also see terms like 3.5G (or 3.75, 3.9 etc. -- almost there) and 4G (the latest and greatest on the horizon). In fact, as early as 2008 we started seeing the transition
towards 4G services. The standard for 4G, however, wasn't finalized by the ITU-R until 2009, setting peak speed requirements for 4G service at 100 Mbit/s
for high mobility communications (such as from trains and cars) and 1 Gbit/s for low mobility communication (e.g., stationary users and pedestrians).
Not all devices and networkds marketed as 4G actually meet the requirements of the standard. On December 6, 2010, ITU declared that
current versions of Long-Term-Evolution (LTE), mobile WiMax and other evolved 3G technologies that do not fulfill all the requirements of the standard can still be considered as
4G, as long as they provide clear forerunners to the full IMT-Advanced requirements and represent 'a substantial level of improvement in performance and capabilities with
respect to the initial third generation systems now deployed.' As the deployment of 4G, like earlier generations, will involve the complete
replacement of existing handsets and networks, it will also take many years for implementation.
Candidate 4G systems replace CDMA spread spectrum radio technology used in 3G systems and IS-95 with
wide channel OFDMA and Single Carrier FDMA (SC-FDE) technologies, MIMO transmission and an all-IP based architecture. There are a number of different technologies under development as well as
different standards for these technologies.
For ease of reference, we've combined information on all the "Gs" on this page.
The articles, resources, references and links below may help you through this maze of alphabet soup, jargon, acronyms
and confusing standards!