Worldwide shipments of dual-mode cellular/WiFi VoIP handsets will exceed 300 million units by 2011, a new report from ABI Research suggests. As we have reported in the past, however, the expected arrival of femtocell AP toward the end of the report's forecast period may well prove "disruptive for the market," as ABI puts it.

Femtocell APs are also known as 3G APs, and they are small cellular base stations designed for use in residential or corporate environments. As is the case with WiFi APs, femtocell APs connect to the customer's own broadband connection. Femtocell technology offers greater network efficiency, better in-building wireless coverage and a more suitable platform for fixed mobile convergence services, ABI says. At least in theory, femtocell obviates the need for the complexity and cost of WiFi in handsets. "Some operators now believe that they don't need to subsidize more expensive Wi-Fi-enabled handsets; they can use the handsets they have, and put femtocells in the home," ABI's Philip Solis says.

Of the 300 million dual-mode units forecast for 2011, Solis expects that handsets based on 802.11n will outnumber those of other protocols. "Cellular handset vendors have made sure that their voices have been heard in the 802.11n standards process, so they are getting all the optional features that they want," he says.

For more on femtocell's challenge to WiFi
-see ABI Research's Web site