The LTE (Long Term Evolution) modems shown at ITU Telecom World are still very much under development and will be ready to ship toward the end of next year, according to vendors.

ZTE has provided the most detailed specifications of its upcoming modems.

Currently, it's waiting for Qualcomm to start shipping the commercial chipsets. That will happen in September, which will leave it just enough time to get products out before the end of the year, said Xiaodong Zhu, CTO at ZTE in Western Europe, in an interview at the telecom conference.

But the operators aren't convinced that ZTE and the other modem manufacturers will be able to do that. A unanimous panel of operators, including AT&T, NTT DOCOMO and Telefónica, voiced concerns about their ability to have devices ready by the end of next year.

The availability of devices is one of the reasons AT&T has decided to launch LTE in 2011, according to Kristin Rinne, senior vice president of architecture and planning at the US operator. It is much more reasonable to launch during 2011, because then there will be a variety of devices, she said.

The chip vendors are doing their best to ease the concerns of the operators. Qualcomm and its partners will have products ready for the early launches of LTE by the end of 2010, said Vieri Vanghi, senior director of product marketing at Qualcomm, during a separate panel debate at the conference.

ST-Ericsson is also reporting forward progress.

"We are in a phase where we have all the hardware available and we're working on integrating it with the software," said Jörgen Lantto, executive vice president and CTO at ST-Ericsson, who says that products will be ready during the second half of next year.

The first phones are then set to arrive in 2011. Developing them will not be a trivial matter.

New technology comes with challenges. And for the first generation of devices, the challenges will be the usual ones: power consumption, size and price, according to Lantto. Also, to get all the performance that LTE can offer requires advanced antenna constructions, he said.

The number of different frequencies that the chipsets have to support makes the LTE development process complicated, according to Vanghi.