Parks Associates (http://www.parkassociates.com) says 3G subscribers will double over next five years, with global 3G+ tablet sales to exceed 68 million by 2015.

The research group forecasts more than 68 million of the 126 million tablets sold worldwide in 2015 will have 3G or greater technology. The research firm’s latest report shows 29% of the 16.5 million tablets sold in 2010 featured embedded 3G technology, while tablets with 3G/4G technology will account for over one-half of all tablets sold in 2015.

“We are seeing strong consumer engagement in data-intensive services and activities, such as social networking, uploading photos to the Internet, and watching online video, on mobile phones,” says Jennifer Kent, a Parks Associates’ mobile research analyst. “By offering the same mobile Internet capabilities as a smartphone, but with better visual and computing experiences, tablets will also benefit from these consumer behaviors.”

Consumer demand for mobile data will increase further as carriers continue to deploy 3G and 4G networks around the world, enabling better user experiences and opening new markets to reliable mobile Internet access. According to the Parks Associates report, 3G subscribers will double over the next five years to account for 47% of total mobile subscribers in 2015, with an additional 5% of mobile subscribers receiving 4G service. The ability to turn this growing data usage into revenue will be the key challenge for carriers going forward.

“Carriers need to optimize network performance, be selective about subsidizing mobile platforms, and monetize Wi-Fi assets in order to stay profitable,” says Harry Wang, director, mobile research, Parks Associates. “Additionally, carriers need to offer more pricing options with flexible rules to fit consumers’ access needs.”