While 2G technologies have given rise to an explosion in mobile phone usage worldwide, they have only served to whet the appetite of carriers and consumers alike. A new breed of technologies offers even higher call capacities and higher data bandwidth. Most importantly, this new breedbeginning with the launch of a group of services known as 2.5G in 2001introduces packet-based networking to the wireless world. Packet-based networking allows for more sophisticated billing capabilities (based on actual data usage, not just minutes used), improved quality-of-service management, and faster data connections. The key to 2.5G technologies is that they can be deployed via relatively simple and inexpensive equipment upgrades without requiring carriers to undertake a total network upgrade. The first 2.5G technology, General Packet Radio Service (GPRS), will begin to appear in 2001 and will offer an "always-on" connection for mobile devices that support it. GPRS supports a theoretical maximum bandwidth of 115.2 Kbps, but actual bandwidth for users will probably be somewhere around 14.4 Kbps. For information on GPRS, visit http://www.wirelessdevnet.com/channels/wireless/features/gprs.html.
A separate technology, known as EDGE, provides a path for GSM and TDMA to converge on the road to 3G. EDGE offers a maximum bandwidth of 384 Kbps across eight timeslots and also offers an evolutionary path from GPRS to UMTS (a 3G technology). Unfortunately, EDGE has had a difficult time making it out of the labs and into the field, forcing many in the industry to speculate that EDGE may be skipped outright in favor of 3G technologies. On the flip side, some question the need for carriers to move aggressively beyond EDGE to 3G; both 3G and EDGE promise 384 Kbps throughput, and many are convinced that the business model for high-speed wireless data in smaller North American markets is questionable at best. Despite these questions, carriers are falling all over themselves to outbid each other in 3G spectrum auctions across the worldbetter to face the "business case" question further down the road, I suppose!
CDMA networks, in general, won't pass through a 2.5G phase. The current version of CDMA, IS-95A, can be upgraded to a higher-bandwidth/higher-capacity version (IS-95B) through a software upgrade. Unfortunately, IS-95B is not yet ready and may not arrive before a component of CDMA's 3G offering, 1XRTT, is ready. This may mean that customers will have to sit and wait for perhaps five years before seeing any significant new capabilities.