The other major family of cellular network technology, CDMA, is the set of standards on which U.S. carriers Sprint Communications Co. L.P. and Verizon Wireless have built their networks. The set of 3G network technologies that belong to the CDMA family is known as CDMA2000, which, as with the GSM alternatives, come in successively speedy iterations.The performance that 1xRTT services offer is good enough for most general network access requirements, such as linking to corporate resources over a VPN and interacting with Web-based applications. Sprint and Verizon Wireless each offer CDMA2000 1xRTT services in most metropolitan areas. Sprint calls its 1xRTT service Sprint PCS Vision, and Verizon calls its 1xRTT service NationalAccess. The next step beyond 1xRTT is CDMA2000 1xEvDO (Evolution Data Optimized), which boosts typical transfer rates to between 300K bps and 500K bps. Verizon Wireless offers 1xEvDO service under the product name BroadbandAccess in 16 U.S. cities. Click here to read more about Verizons EvDO rollout. As its name suggests, 1xEvDO supports data transmission only. A follow-on called 1xEvDV will provide for both voice and data transmission, but neither Sprint nor Verizon Wireless has deployed such a network so far. As with UMTS and UMTS/ HSDPA on the GSM side, the performance that these next-step CDMA2000 networks make possible begins to erase the distinctions that enterprises must now make between the applications they can deploy to mobile users and those they can deploy to fixed broadband users. Taking a route separate from the GSM or CDMA paths traveled by other major U.S. carriers is Nextel Communications, which offers data services based on IDEN (Integrated Digital Enhanced Network). Nextel currently offers data services with transfer rates of about 15K bpsawfully poky compared with the competitionalthough Nextel is in the process of upgrading its network with an IDEN extension called WIDEN, which should boost data rates to about 60K bps to 80K bps. Its unclear at this point whether or how Nextel will boost its data services to 3G speeds. However, the carrier is conducting a network trial using Flarion Technologies Inc.s FLASH-OFDM, which stands for (take a deep breath now) Fast Low-latency Access with Seamless Handoff Orthogonal Frequency Division Multiplexing. FLASH-OFDM offers transfer speeds in excess of 1M bps. Senior Analyst Jason Brooks can be reached at firstname.lastname@example.org. Check out eWEEK.coms for the latest news, reviews and analysis on mobile and wireless computing.
The first and most widely available of these is CDMA2000 1xRTT (Radio Transmission Technology), which delivers transfer speeds of up to 144K bps and straddles the line between whats considered 2.5G and 3G.