The market research company now believes about 350,000 femtocells will have shipped by the end of the year. This is "adjusted" from 790,000 figure ABI forecast for the year in April 2009.

The market researcher said the new number reflected "slower-than-expected adoption of femtocells by mobile operators." The market researcher did not say it had made a mistake in its earlier prediction.

"We expect that deployments in 2010 will pick up but will be slower than expected — our data suggests about a 40 percent reduction on previous estimates," said practice director Aditya Kaul, in a statement.

All the large operators in the U.S. have femtocell offerings including AT&T, Verizon and Sprint. Vodafone in the U.K. also has a femtocell service and recently China Unicom announced its femtocell offering.

Kaul points to a combination of factors behind the slow deployment of femtocells including: the general economic malaise, which makes the $150 price tag of an unsubsidized femtocell unit hard to swallow; the time operators need to get their systems and networks ready for a femtocell deployment and to devise pricing plans; a fear in some quarters that a rapid increase in femtocell numbers would cause interference in the macro network. Kaul concluded: "We still believe in this market's potential. We anticipate that by 2014, shipments will only be about 10 percent lower than our previous estimates. The drivers are real, but it will take longer than anticipated. Next year will be critical: if conditions don't improve by the end of 2010, some smaller vendors may find themselves in trouble."

Related links and articles:

Analyst: waning interest in femtocells is only temporary

Femtocells to see 70 million users in 2014, says research firm

Percello to demo 16-way femtocell chip