Today's wireless technology—cellular networks

Four of the five North American cellular networks fall into two main camps: code division multiple access (CDMA) and global system for mobile communication (GSM):

• Sprint PCS and Verizon Wireless offer CDMA2000 1xRTT networks in most areas. They provide throughput of about 30Kbps to 50Kbps. That's adequate for e-mail and short database queries, but little else.
• Cingular Wireless and T-Mobile offer GSM general packet radio service (GPRS) in most areas, providing the same throughput of 30Kbps – 50Kbps.
• Nextel Communications, the fifth major U.S. carrier, uses Motorola's iDen cellular technology, which offers throughput of about 35Kbps. Nextel's merger with Sprint likely means it will move to CDMA technologies.

Tomorrow's wireless technology

• Sprint PCS and Verizon Wireless

  To provide greater bandwidth, Sprint PCS and Verizon Wireless are migrating to CDMA2000 1xEVDO, which offers throughput of 100 to 300Kbps, which is up to four times faster than the earlier generation. Verizon already offers the new service in 30 major U.S. cities (including New York, Atlanta and Los Angeles) and expects to make it available nationwide by the end of 2005. Sprint plans to launch EVDO service in 2005, but has not said which cities will get it first.

  One Verizon 1xEVDO customer, Optimus Solutions, claims connection speeds of about 250Kbps, which allows users to receive large files such as PowerPoint presentations quickly. While slower than a home broadband connection, Verizon's 1xEVDO networks are less expensive (at about $80 per month per user) than paying for broadband connectivity that confines users to hotels or Wi-Fi hot spots.

• Cingular Wireless and T-Mobile

  Cingular and T-Mobile's next iteration, Enhanced Data GSM Environment (EDGE), offers throughput of 50Kbps to 200Kbps – significantly less than CDMA2000 1xEVDO. The version beyond that, UMTS, provides 100Kbps to 350Kbps speeds. But Cingular currently offers UMTS service in only six cities (with a national rollout slated for later this year), EDGE in about half its coverage area and GPRS, the slowest network, in the rest.

  T-Mobile, meanwhile, offers just GPRS and plans to offer UMTS service in 2007. But GSM does have an advantage: Although slower, GSM networks operate in much of the world, providing broadband access to global travelers.

• Data-only connections

  Three new technologies provide data-only connections:

  • Flash orthogonal frequency division multiplexing (OFDM)
  • The Institute of Electrical and Electronics Engineers' (IEEE) 802.16 (popularly known as WiMax)
  • Universal Mobile Telecommunications System's telecommunications display device (UMTS-TDD)

It is not clear which vendors may be adopting any of these three technologies.

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