With transmission speeds that rival digital subscriber line and cable modem connections, third-generation wireless data networks are intended to bring mobile users the same rich multimedia applications now available across wired links.
However, while many of the details of 3G and beyond remain unclear, U.S. carriers are beginning to offer wireless data services that deliver speeds comparable to those from a 56K-bps modem—plenty of bandwidth for messaging and basic Web browsing. Loosely referred to as 2.5G, these services are a steppingstone between todays 2G digital networks and the 3G networks of tomorrow.
Along with increased speeds, 2.5G networks are packet-switched, rather than circuit-switched, which among other things means that 2.5G connections are always on. So, for example, 2G wireless users that must dial in to the Internet to check e-mail can, on 2.5G networks, be prompted as messages arrive. In addition, 2.5G data usage is measured by the kilobyte, rather than by the minute, which should result in lower wireless data costs.
The two major 2.5G service contenders are GPRS (General Packet Radio Service), which is built atop GSM (Global System for Mobile Communications) digital networks and 1xRTT (the first phase of the 3G CDMA technology), which extends todays CDMA (Code Division Multiple Access) networks.
While slightly slower than CDMA2000 1xRTT, GPRS will have the benefit of operating across the 170 countries that have standardized on GSM.
VoiceStream Wireless Corp. markets its GPRS service under the brand name iStream. AT&T Corp. offers GPRS service in Detroit, Las Vegas, Phoenix, Seattle and Portland, Ore. AT&T has announced plans to deploy GPRS in all of the markets it serves by the end of next year. Cingular Wireless LLC has rolled out GPRS services in Las Vegas and parts of the Carolinas, Tennessee and Georgia. Cingular plans to extend GPRS to all its customers by early next year.
Wireless services based on CDMA2000 1xRTT havent yet spread as far as GPRS services. Sprint Communications Co. LP and Verizon Corp., both of which operate CDMA networks, have announced plans to begin rolling out CDMA2000 1xRTT next year.
In part, 1xRTT rollout is being held up by handset availability. For GPRS networks, Motorola Inc. and Ericsson AB each market tri-band handsets that operate on North American and European GSM and GPRS networks. In addition, Handspring Inc. has announced that its Treo smart phone will support GPRS beginning in the first half of next year.
Mobile users will also be able to access 2.5G networks with PC Cards—Sierra Wireless Inc. and Novatel Wireless Inc. are each readying GPRS and CDMA2000 1xRTT versions of their AirCard and Merlin wireless network access cards, respectively, and Xircom Inc. will launch a GPRS version of its CreditCard product.