Three of Northeast Asia’s largest carriers – Japan’s NTT DoCoMo, China Mobile, and South Korea’s KT, on Wednesday established a broad business partnership focused on international roaming for voice and data services.

A business cooperation committee to be set up by the three companies will consider opportunities for collaboration, with a focus on the rising popularity of smartphones. Specific areas to be looked at include international roaming, enterprise services, LTE and other network technologies, smartphones and common platforms.

According to Informa Telecoms & Media, sales of 3G/4G devices in China will hit 357.6 million by 2015; In Japan will reach 166.6 million; and in South Korea will reach 44.4 million by 2015.