A Financial Times says Schmidt made the prediction on Wednesday at the Cannes Lions advertising festival in France. The technological advancements required to make mobile wallet systems a reality are almost in place, said Schmidt, who spoke at the conference.

Mobile phone vendors are adding Near Field Communication (NFC) chips to their handsets. NFC technology enables two-way interactions between a mobile device and a bank, retailer, government agency or some other institution. NFC-ready smartphones can exchange information with other NFC devices, as well as read data from smart tags in posters, stickers, and other items, Google says.

Google last month launched , an NFC-based mobile payment system built into the Android 2.3 operating system. The service is limited currently to Google's Nexus S 4G phone on Sprint, but that will change soon. Google is urging payment processors to upgrade a third of their terminals to accept NFC transactions, a move that would spur widespread adoption of the technology, Schmidt said.

Because so many players are required to make the mobile wallet system work, however, Schmidt can't provide a more exact timetable, the Financial Times reports.

"I judge that based on how long I think it takes, because the terminals are available now, the software is available now or this summer," Schmidt said.