NEW YORK ( TheStreet) -- China, the world's largest mobile phone market, recently crossed the one billion mobile connections mark in March. To put this number in perspective, the U.S. currently has just over 330 million active connections in all.While the Chinese figure may not be reflective of the actual number of mobile users in country, as some of these connections are currently inactive, it is still a compelling statistic that shows the huge growth opportunity that China presents for many smartphone manufacturers. At the same time, it is also a huge opportunity for the incumbent Chinese telecom providers such as China Mobile ( CHL), China Unicom ( CHU) and China Telecom ( CHA)to tap their huge 2G subscriber base and drive the demand for the more lucrative 3G data services. Of the three Chinese carriers, China Telecom may be the smallest but its subscriber base of over 135 million (135.83 million as of March) easily puts most wireless carriers in the developed world to shame. The largest wireless carrier in the U.S., Verizon, has about 110 million total connections currently and it operates in an increasingly saturated market.