TOKYO, Jan. 7 -- The next two to three years are critical for China's ambitions to become a global leader in 5G, according to a leading think tank.

The state-backed China Academy of Information and Communications Technology (CAICT) says despite the huge buildout and takeup, China's 5G is still immature.

In a new white paper on China's 5G outlook, CAICT said the key to 5G was its ability to expand the industrial Internet.

It said the industrial Internet would ultimately be driven by network capabilities, terminals and system products.

But it warned that the 5G rollout was still far from complete, while supporting industries for 5G applications were immature and "the cross-industry ecosystem," essential for the convergent nature of 5G, ...