Testing times for big firms as profit growth slows

China's big three telecom carriers find themselves being squeezed after rolling out high-speed 4G technology.

Mounting pressure from the government and growing dissatisfaction from customers have added to the problems facing State-owned giants China Mobile Ltd, China Unicom (Hong Kong) Ltd and China Telecom Corp Ltd.

"The expansion of 4G networks has triggered public demand for increased data traffic, which is growing quickly to offset losses in voice calls and text messaging," Fu Liang, a veteran independent telecoms expert, said.