A primer on 3G

       The standard known as 3G, or Wideband CDMA, IS-95, was developed in 1995 but it was not until the early 2000s that it was deployed commercially.
       The names are confusing - WCDMA is an evolution of the European-centric GSM For 4G, while WCDMA evolved into LTE (Long Term Evolution).
       CDMA, the American 2G standard, evolved into CDMA EV-DO, which is also deployed in Thailand outside of the central provinces by CAT. Later, it evolved into the Ultra Mobile Broadband standard (UMB). However, it seems that all carriers, even those using EV-DO, are now focusing on LTE for 4G and that UMB is to all intents dead in the water.
       Frequencies can also be confusing. At first, virtually all WCDMA 3G (we are not talking about EV-DO) were at 2100 MHz or 2.1 GHz in Europe and most of Asia. Australia went with 850 MHz and the USA, always intent on doing things differently from the rest of the world, went with a combination of 850 and 1900. Today, Europe is moving to 900/2100 (re-farming old 900 GSM). In Thailand, TrueMove and DTac use 850 and AIS uses 900 for their trial networks. Most new phones imported to Thailand are Euro-spec, meaning 900/2100; the iPhone, Blackberry and most HP Windows Mobile devices being the major exceptions with 850/2100.
       Lower frequencies are better, with both bigger cells and better indoor coverage. However, there is not enough low-frequency space available to meet demand from everyone who wants it.
       Speeds are going up and up. WCDMA started at just 384 KBPS (about 0.38 MBPS). Now HSDPA (High Speed Downlink Packet Access) has a top speed of 14.4 MBPS. However, most networks say that the latest 7.2 or 14.4 upgrades are their last as they are now gearing up for 4G LTE as their next upgrade.
       By next year, some countries will have rolled out 4G LTE commercially. Yet Thailand still has not decided on how to license 3G.