Field trials of HSDPA have confirmed that technology's cellular data speeds of more than 1 Mbps, but it is subject to problems that can significantly degrade those speeds, Motorola acknowledged in a report it released Monday.

The problems are all solvable if the cellular operators take specific steps, the company said. HSDPA is the next generation of 3G that will be deployed by operators that use GSM-based cellular technology. In the U.S., Cingular has said it will start deploying HSDPA in a few markets later this year with a wider roll-out in 2006.

Motorola, perhaps best known among wireless users for its cell phones, also is one of the largest developers of cellular infrastructure equipment used by operators. The Motorola study, which was conducted in Europe, found three specific problems.

First, it noted that video performance will degrade significantly and even freeze up when "a relatively modest number of users are active." Operators can solve that problem by properly prioritizing video services or by providing more infrastructure capacity, Motorola said in a statement.

The study also found there is the potential of significant latency -- or delays -- when using applications such as Web browsing. The delays are caused by the fact that HSDPA equipment can perform so-called state-switching, which switches users from lower speeds to higher speeds without their knowledge. The potential delay could be several seconds and could lead to user dissatisfaction, Motorola said.

The company said that the problem can be avoided by operators simply not using state switching or reducing its use. In addition, operators can use a built-in technology called scheduling, but that requires a lot of processing power to be available at cellular base stations.

The third problem pinpointed by Motorola is that mobile devices need sufficient power to receive the signals, particularly when the user is on the move. Built-in functions are available that can increase data rates when devices are on the move by as much as 40 percent, but few devices currently have this capabilities.

"Motorola's HSDPA experience is industry leading and through the identification of these three guidelines, a result of the real-life trials, we can help operators significantly enhance the consumer experience of HSDPA at launch," Raghu Rau, Motorola's senior vice president for global marketing and strategy, said in a statement. "The trials are specifically designed to help build optimal performance HSDPA-enabled networks and to effectively deploy services on those networks."