Miao Wei, the industry and information technology minister, said earlier this year that the nation would add more than 200 million 4G users in 2015. China Mobile Ltd, the largest carrier by subscriber numbers, said it aims to have 250 million 4G users by the end of this year, meaning the company itself needs to add about 160 million new 4G subscribers this year.

Although the carriers have introduced an array of promotions and the 4G charges have been dropping as more subscriptions have diluted costs, customers are still complaining about the increasing traffic charges after adopting the 4G service.

Zheng Xin, who works at a real estate agency in Beijing, said he spends more than 50 yuan ($8) every month to purchase extra traffic quota.

"I only get 1 gigabyte of quota for 50 yuan, so I'm trying not to waste it on non-essential matters," he said, adding he usually downloads videos using a Wi-Fi connection and opts for low-quality streaming content while using 4G.

The carriers did not comment on the matter. A China Mobile employee familiar with the 4G business said if one were to factor in the huge expenditure incurred by the carriers for setting up infrastructure, the fees are not high at all.

Xiang, the industry expert, said besides adding technology investment, the regulators should mitigate profit targets for the carriers, which are all State-owned enterprises.

"Building a 4G network that covers the entire country requires mammoth investment and every carrier is struggling to meet the profit targets set by the State-owned Assets Supervision and Administration Commission," Xiang said.

He said attracting investment from the private sector will help ease the burden for the carriers.

China is gradually opening up the telecom industry to private capital. Non-State companies are allowed to provide value-added services using the carriers' infrastructure.

The carriers are planning total 4G investment of 153 billion yuan this year, a jump of nearly one-quarter compared with the previous year, the financial reports showed.