Although CDMA dominates the US market, globally it is dwarfed by GSM. According to the CDMA Development Group, at the end of last year, there were around 200 million users of its technology; this contrasts with one billion GSM customers at the beginning of this year (see an excellent white paper for details).
The poor data transfer speeds of 2G technologies – typically around 10 kilobits per second – render them unsuitable for Internet activities except perhaps the occasional email. This has led to various extensions to the main radio standards, sometimes known as 2.5G technologies. For GSM there is GPRS (General Packet Radio Service), which offers ten times the speed of basic GSM, while an extension to CDMA called CDMA 2000 1X claims even better results. The GSM world’s answer to CDMA 2000 1X is known as EDGE (Enhance d Data for Global Evolution), which also offers higher throughput than GPRS.
Beyond these lie the third-generation (3G) systems that aim to provide true broadband speeds – several Megabits per second – to mobile devices: Wideband-CDMA (W-CDMA) from the GSM manufacturers (also known as UMTS), and CDMA 2000 1xEV from the CDMA side.
One of the biggest problems in trying to use mobile telephony networks to provide high- speed data access is the presence of these rival standards around the world, coupled with many confusing options (and jargon) for each. To complicate the situation further, a third, quite different approach for high-speed mobile Net access has emerged: WiMAX. Part of WiMAX’s attractiveness for Internet users is that it comes not from the mobile phone companies but the computer industry, and refers to equipment conforming to the IEEE 802.16 standard. It defines a wireless metropolitan area network technology that operates up to 50 km, at data rates up to 70 Megabits per second.
WiMAX forms part of a group of IEEE wireless standards, including the better-known WiFi, formally IEEE 802.11. The two are designed to work together, with WiMAX linking WiFi hotspots and providing last-mile broadband connectivity to homes with 802.11 connectivity.
The present vigour of the WiFi world and the proliferation of public hotspots is an indication of the level of demand for wireless connectivity. This has led to a proliferation of useful sites such as WiFi Networking News (with a good timeline) and WiFi Planet. It has also spurred the development of what are known as mesh networks – patchworks of WiFi hotspots creating a larger-scale radio coverage that could offer yet another way of accessing the Internet while on the move.
Glyn Moody welcomes your comments.