Converged Wi-Fi/mobile phone handsets are expected to make a "big splash" as demand ramps up "exponentially" over the next four years, research has predicted.

A new report from In-Stat said that shipments of mobile handsets containing Wi-Fi will exceed 132 million units in the US alone by 2010. 

The study noted that carriers have been reluctant to offer Wi-Fi capable handsets, but the wireless networking technology has spread so fast that they will not be able to resist for much longer.

"In the end, most US cellular carriers will embrace Wi-Fi in their handsets as carriers know that if they don't, other carriers will, and these carriers will steal some of their customers," said In-Stat analyst Allen Nogee.

In-Stat's report predicts that more than 20 mobile phone models now have, or will soon have, embedded Wi-Fi access.

It also noted that a few mobile carriers are planning to offer services that support voice calls over both cellular and Wi-Fi, and that some Wi-Fi/cellular handsets are incorporating VoIP clients for services like Skype.

The analyst reported that, although it had been assumed that business customers would be first to adopt Wi-Fi/cellular handsets, it is consumers who are likely to be more receptive to early adoption of the technology.