Which way to wireless data?

Is there a “best” route to 3G?

There’s a debate brewing among some wireless service providers on how best to migrate current infrastructures to support data-oriented 3G services. At the heart of the debate are two migration paths that seek to do the same thing: improve data rates from the current 14.4Kbps to 2Mbps and higher.

The migration paths are the Code Division Multiple Access (CDMA) 1XRTT standard, which boosts data rates to 144Kbps, and the GSM upgrade called General Packet Radio Service (GPRS). GPRS, which is a time-division multiple access (TDMA) technology, can run at 171.2Kbps when all eight of its timeslots are used.

Both CDMA 1XRTT and GPRS are considered interim steps to 3G – typically called 2.5G – because they fall short of the 384Kbps support required for any 3G network. The ultimate goal is 2Mbps and above.

GPRS is deployed in about two-thirds of the world, and is being implemented in the U.S. by AT&T Wireless Group Inc. and Cingular Wireless LLC. Meanwhile, 80 per cent to 90 per cent of the wireless coverage in the U.S. is CDMA-based.

Indeed, the debate may be settled along geographical lines unless a groundswell of compelling applications tips the scales toward one technology or the other.

“All that really matters is what these guys are doing with services,” says Larry Swasey, an independent wireless analyst. “Depending on what the subscriber wants, either technology could be fine.”

Perhaps, but wireless operators beg to differ.

Tom Crook, director of technology research at Sprint Corp., says the company chose to be bullish on CDMA back in 1995 because of the value the technology showed in migration to 3G.

“If its CDMA (1XRTT) or WCDMA, it’s still all based on CDMA,” he says. “By choosing to go CDMA, we chose to evolve ourselves in an efficient manner to 3G.”

WCDMA, or Wideband CDMA, offers data rates of 384Kbps and is planned for implementation in 2003. Its counterpart in the GSM/GPRS world is Universal Mobile Telecommunications Service (UMTS).

In addition to the extensive coverage in the U.S., CDMA is also supported abroad in South Korea, Japan and China, Crook says. Crook says getting to 3G via the GPRS route would be too disruptive.

“In order for us to achieve the higher data rates of 144Kbps peak with 1XRTT, all we have to do is go into the base station and plug in a card,” he says. “In addition, the next 3G 1x release, due around 2003, will only require us to perform a software upgrade. Those GSM/GPRS network operators will have to turn up new frequencies, another 10MHz of spectrum just to maintain the customers they’ve got while they perform the upgrade.”

That’s not enough to dissuade Cingular. The carrier’s decision to go the GSM/GPRS route is based on market share, says Chris Rinne, vice-president of technology and product realization for the carrier.

And Rinne disputes allegations that it will be the more expensive way to get to 3G.

“Five hundred million-plus use GSM technology globally,” he says. “That’s a 70 per cent market share. Couple that with the lower equipment costs, lower handset costs and spectral efficiency, and GSM has the better advantage.”

Rinne says CDMA networks will also face multi-faceted upgrades to get to 3G, even if 3G happens to be based on CDMA technology.

“There are going to be multiple steps with each type of network,” he says. “While GSM networks will eventually add EDGE [Enhanced Data Rates for Global Evolution] capabilities, CDMA networks will have 1XRTT upgrades and similar upgrades beyond that in 1xEvdv (data and voice) and 1xEvdo (data only).”

In addition, Rinne says that upgrading the GSM/GPRS network to EDGE, which touts 384Kbps capacity, will only require a software upgrade.

But the technology question turns out to be moot because the payback comes from the applications and services on those networks, no matter what they’re based on, vendors say. Motorola and Ericsson support both technologies.

“You can really do the same types of services with either technology,” says Lars Nilsson, general manager for Ericsson. “The decision really comes down to what carriers are offering in terms of bundled services and what kind of global roaming capability you need.”

Cingular’s Rinne agrees.

“The real goal here is to have a seamless transition to 3G in order to tailor emerging services to the customers’ needs,” he says. “The only thing the customer really cares about are the applications, and so far, these applications can be leveraged in both technology environments.”

Analyst Swasey concurs. GPRS is good for Short Messaging and Wireless Application Protocol applications, and it generally costs a little less, he admits. CDMA can achieve higher speeds, especially with the 1XRTT implementation, Swasey says.

“It’s really just a value judgement,” he says. “It depends on where you are and what you’re looking for as an end-user.”