China Unicom plans to spend 100 billion yuan (US$16 billion) to upgrade its network and on promotions to woo more 4G users this year, the country's No. 2 mobile carrier said yesterday.

The telco's capital spending in 2015 is an increase from 84.8 billion yuan in 2014 and comes on the heels of a 15.8 percent annual jump in net profit to 12.1 billion yuan last year.

Its revenue, however, slipped 3.5 percent to 284.7 billion yuan, missing analysts' expectations for 286.7 billion yuan.

China Unicom and China Telecom were awarded nationwide licenses for 4G FDD-LTE technology at the end of last month, which analysts said could help the two telcos expand business and challenge China Mobile's dominance.

At the end of 2014, China Unicom had about 300 million mobile users after adding 18 million new mobile users during the year.

It aims to attract about 100 million 4G users by the end of this year, said China Unicom Chairman Chang Xiaobing.

"With the mobile subscriber market saturating and the traditional voice business continuing to decline, the traditional subscriber-driven business growth is under pressure," Chang said.

The ARPU — or average revenue per user, a key measure in the telecommunications industry — will stay "stable," according to China Unicom, saying that it was 63.60 yuan in 2014.

Shanghai-listed China Unicom rose 0.75 percent to 5.40 yuan, compared with a 0.51 percent gain in the local stock index yesterday.

In 2013, China issued the first 4G licenses for the China-developed TD-LTE technology to the three telcos.