On Thursday, AT&T and partner NTT DoCoMo agreed to delay introduction of their "wideband" network until the end of 2004, when service is slated to begin in four U.S. cities: Dallas, Seattle, San Diego and San Francisco.

Initially, the two companies had planned to launch the network by June 2004 in 13 of the 50 largest U.S. markets.

Yet with demand for such services uncertain, AT&T doesn't want to spend too much money upfront.

The revised plan "will allow the company to cover some of the most promising U.S. markets while maintaining a prudent level of capital expenditures," AT&T Wireless said in a press release.

NTT DoCoMo runs a similar service in Japan, but early reviews haven't been encouraging. The service has signed up about 150,000 customers in a little more than a year, just one-fourth of DoCoMo's target.

In the U.S., wireless carriers are under pressure to slash costs, trim debts and reduce "churn" -- or the loss of customers to rivals. In the past few years, growth has tapered off even as competition has intensified, forcing carriers to show improved results to attract investment from a more skeptical Wall Street.

Despite such obstacles, AT&T Wireless still believes that customers will eventually want high-speed access to the Internet from mobile phones. It's working with NTT to develop a "wideband" network based on code division multiple access technology.

CDMA enables networks to carry more traffic at higher speeds. That's helped push the technology to the forefront as an emerging global standard, although a split has developed over which version will win out -- the one developed by U.S.-based Qualcomm or the incompatible alternative championed by NTT and three major European vendors.

AT&T Wireless already offers data or Internet access to customers at much slower speeds, comparable to that of a 28-kilobit or 56-kilobit modem.

In 2003, it plans to deploy an intermediate-speed technology, known as Edge, that could boost access speeds to as much as 384 kilobits a second, half as fast as regular DSL service, under ideal conditions.

Ultimately, AT&T Wireless said it aims to generate speeds of as much as 2 megabits a second with the planned "wideband" network.

That would be three times faster than regular DSL or twice as fast as high-speed cable service, though wireless experts doubt that customers would be able to achieve those speeds most of the time. During times of heavy traffic, speeds could slow considerably.

NTT DoCoMo paid nearly $10 billion for a stake in AT&T Wireless two years ago. Under a revised agreement, the company will be able to add a second member to the U.S. firm's board of directors. NTT wants to promote the W-CDMA standard.

Qualcomm (QCOM: news, chart, profile), for its part, is the main supplier for Verizon and Sprint, whose wireless networks are viewed as superior.

On Thursday, shares of AT&T Wireless (AWE: news, chart, profile) added 13 cents to $6.59.