Some observers commented that the new standard might give some advantage to Ubiquisys, which makes all the femtocells for UMA vendors like NEC and Motorola. Ubiquisys has already promised its devices will be upgradeable - but others are very sceptical given the standard is still not complete.

In any case upgradeability of current products won't be very important, as proper roll-outs won't take place till the standard is finished. "Now it's a race to the finish line," says Shaw.

And there may still be other complications. The standard is designed to work with existing networks, but what if handsets need to be tweaked? "Although existing 'legacy' 3G handsets can work with femtocells, they are not optimised for them," warns Dean Bubley. Operators may have to alter their handsets to get the best out of femtos, which could make a large dent in the business model, he warns.

But in the end, the creation of the standard brings its own message. A standard driven by the operators who will use it much be more likely to succeed. "It's the carriers who are driving this," says Baines. "Some people are interested in the technology, but what counts is customer pull, rather than white papers about funky technology."