November 6, 2000

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Wireless Data
The Road To A Wireless Future

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By Peter Rysavy, reprinted from Network Computing

More on wireless:

sidebar:The Battle For Cellular Supremacy Companies Turn To Outsourcing For Wireless Services (10/30/00) THE NEW WIRELESS ENTERPRISE (9/18/00) Network Computing: The Road to a Wireless Future (10/30/00)

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Operators already have GPRS in field trials. VoiceStream plans to turn on its service by the end of this year. By 2001, service should be available in many countries, though it may take another year before users can easily roam among service providers on a global basis.

A new radio interface, called EDGE (enhanced data rates for global evolution), will propel GPRS to rates of 384 Kbps and a little higher under optimum radio conditions. Compared with GPRS, EDGE will be a costly upgrade for operators, many of whom might leapfrog EDGE and go directly to 3G systems.

The 3G solution for GSM is called Wideband CDMA (W-CDMA), also known as Universal Mobile Telephone System. W-CDMA will require new radio spectra because it operates in ultrawide 5-MHz radio channels. This type of CDMA differs from the competing 3G technology, CDMA2000 (see story below). Auctions for new spectra have begun in Europe and other countries, but auctions in the United States won't occur until next year.

W-CDMA meets the IMT requirements of 384 Kbps outdoors and 2 Mbps indoors--but don't hold your breath for service. The earliest initial deployment will be by NTT DoCoMo in Japan in 2002, with other operators beginning in 2003 and later.

Despite its size, the cellular industry cannot support three different cellular technologies worldwide. For this reason, the Universal Wireless Communications Consortium, which represents TIA/EIA-136 operators worldwide, has made a strategic decision to base its packet-data architecture on GPRS standards. By using the EDGE radio interface and a GPRS infrastructure, TIA/EIA-136 operators will be able to offer a data service, referred to as EGPRS-136, by 2002.

EGPRS-136 will let data customers roam between TIA/EIA-136 and GSM networks. Speeds will match EDGE performance for GSM networks: 384 Kbps and faster. Unfortunately, widespread service probably won't be available until 2003, and in the interim, customers will have to make do with networks such as AT&T's Wireless IP service, which is based on CDPD technology. This situation could put TIA/EIA-136 operators at a significant competitive disadvantage if wireless data really starts to take off.

One question is, what happens beyond EDGE? TIA/EIA-136 operators could adopt W-CDMA in new spectra. They could also go directly to fourth-generation technology, which means almost anything beyond 3G.

Today, CDMA networks based on the IS-95A standard offer circuit-switched data service up to 14.4 Kbps, with actual throughput closer to 13 Kbps. Operators in Japan and Korea have adopted an enhanced version of the standard, IS-95B, which increases data rates to about 64 Kbps and is packet-based. However, U.S. CDMA network operators are planning to skip IS-95B and proceed directly to CDMA2000, which comes in versions 1X and 3X. Operators can readily deploy 1X technology in existing spectra but may have to wait for new spectra to deploy 3X, which combines three CDMA 1.25-MHz radio channels for higher-performance services.

CDMA2000 1X is a strong interim step for CDMA operators. Through improvements in modulation, power control, and data encoding, it doubles voice capacity and adds a packet-data capability of up to 153 Kbps. Operators such as Verizon and Sprint PCS expect to start offering service in 2001. Because CDMA operators have broader coverage than do GSM operators in the United States, the 1X service could be the strongest candidate for higher-speed wireless data in 2001, and IT managers should monitor its deployment carefully.

The architecture of CDMA2000 (see chart above) is fundamentally different from that of GPRS. Rather than use specialized data infrastructure based on cellular-specific protocols, CDMA2000 leverages Internet developments and includes Point-to-Point Protocol to link users to a packet data-serving node and Mobile IP to support customers roaming among CDMA2000 networks. In fact, the Mobile IP option will let customers with their own IP addresses roam into CDMA2000 networks and keep those addresses active.

Beyond 1X, the data possibilities of CDMA branch out. CDMA2000 3X, using the same architecture as 1X, offers 384 Kbps outdoors and 2 Mbps indoors, but operators will most likely need to wait for new spectra. However, Qualcomm has offered a new option: a technology once called HDR (High Data Rate) and now referred to as 1XEV, signifying an evolution of 1X technology. 1XEV uses a 1.25-MHz CDMA radio channel dedicated to and optimized for packet data, with throughputs of more than 2 Mbps. Operators can deploy 1XEV in conjunction with IS-95A or 1X networks, or they can deploy 1XEV-only networks. Although no operator offers 1XEV service at present, several are planning to test the technology next year.

Cellular technology gets the biggest share of attention, but network managers should keep their eyes open for other wireless providers. One is Metricom Inc., which is rolling out a wireless data service called Ricochet2, with rates of 128 Kbps. With strong backing from WorldCom and Paul Allen, Metricom expects to deploy service in more than 35 metropolitan areas by 2001, reaching 100 million potential subscribers. If cellular carriers execute their data plans aggressively, Metricom might offer too little, too late--but if cellular carriers stumble, Metricom could scoop up bandwidth-starved mobile customers.

Despite other industry efforts, the cellular network operators are in the best position to deliver high-speed wireless data over huge coverage areas thanks to their broad voice networks. They also have the deep pockets needed to finance these projects. All the technologies have sufficient momentum and backing to be deployed, so there is little technology risk for users. Most wireless networking applications will be based on IP, so going from one network to another will be almost as easy as buying a new modem.

There are enough wireless data options available today that you shouldn't wait for these new services to dip your toe in the ether. But realize that today's mobile wireless connections rarely can substitute directly for a wired link.

Instead, you'll be working with a subset of your data--which means you will have to configure your applications carefully, use middleware or wireless portals, or engage the services of a wireless application service provider. Consequently, only a small subset of your communications-oriented applications will make sense with today's wireless networks. But that's a good place to start, as there are lessons to be learned that will carry over to newer services.

For instance, you will develop business relationships with wireless service providers, learn how applications function or fail as they go in and out of coverage, and get a better understanding of the applications people need for maximum productivity when roaming and how to support those apps.

By being up-to-date on the technology, you will be in a much better position to evaluate newer services as they become available. You also will have a much better grasp of the expanded set of applications that these new networks will support.

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