For CDMA2000, the evolution path includes a technology called 1XEVDO (1X Evolution Data Only), which boasts peak throughputs of 2.4 Mbps and 1XEVDV (1X Evolution Data and Voice), which will have peak downlink speeds of 5 Mbps.
Keep in mind these factors when you consider the future of wireless data:
• Peak speeds are not the same as average speeds. For instance, though WCDMA tops out at 2 Mbps, this represents the total cell capacity; typical users will likely get 200 Kbps to 300 Kbps throughput on a loaded network.
• These deployments will take time. Though EDGE, essentially a network-software upgrade, is almost here, WCDMA and 1XEV deployments could take several years. These technologies will be more expensive and complicated and will require a new radio-access network.
• Business plans for 3G networks are up in the air, with demand for wireless data services uncertain and the rapid deployment of public WLANs possibly channeling user-data subscriptions away from cellular networks. Following the overall telecom meltdown, many operators are delaying their 3G deployment plans.
• Spectrum is an issue. Operators can deploy EDGE and CDMA2000 easily in existing spectrum, but WCDMA uses 5-MHz radio channels--it's not called wideband for nothing. Finding room for these channels won't be easy. Most countries in Europe and Asia have auctioned new 3G spectrum for 3G service. The United States is a little further behind, having just recently identified which bands might be feasible.
Meantime, GPRS and 1XRTT are real. Which is the better service? 1XRTT has a throughput advantage for the moment, but GPRS is available in more countries. And the upgrade to EDGE should more than match 1XRTT, though users will need new equipment to take advantage of the service. From all other perspectives, the offerings are largely equivalent. The table on page 78, "Wireless Technology Time Line," compares capabilities and deployments of the different cellular technologies.
Using the Networks
Getting started with these networks is easy, but getting full satisfaction requires attention to detail. Establishing connections is straightforward, IP-based applications work immediately, and you can almost instantly realize the convenience of anywhere, anytime communications. But you must consider where service is available, which platforms to use, performance variations, security, usage costs and networking idiosyncrasies. Fortunately, these are manageable once you understand them.
Service availability is the best place to start because if you don't have service, the rest of the points are moot. All the operators are planning nationwide service, and if you can get voice service, you will be able to have higher-speed data service, a significant improvement over networks such as CDPD, in which service coverage does not match the voice footprint. But this won't happen overnight. T-Mobile offers GPRS everywhere it offers GSM voice service, but AT&T Wireless and Cingular Wireless use TIA/EIA-136 TDMA technology for their voice networks and are rolling out new GSM/GPRS networks. AT&T Wireless expects to have most of its network deployed by the end of this year; Cingular Wireless, by the end of 2003.
On the CDMA side, the two largest operators are upgrading their existing networks to 1XRTT and both will offer broad coverage by the end of this year. Sprint PCS has upgraded most of its network, and Verizon Wireless says it expects to cover 90 percent of its 30 million subscribers by year's end. Check with the operators. Most show coverage maps on their Web sites for these services.
Increasingly, customers are asking about global coverage, and here GPRS has the advantage of availability in 64 countries. However, make sure your provider has a roaming agreement with a foreign operator in the country of interest. In addition, GSM operates in different radio bands in different locations, so your device must be able to tune to the appropriate frequencies. Fortunately, multiple-band GPRS phones and modems are available.
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