China Unicom, the country's second largest telecom carrier by subscribers, is doubling its 4G services to catch up with market leader China Mobile.

The State-owned company announced that it is purchasing telecom equipment for 469,000 new 4G base stations.

The estimated 24 billion yuan ($3.7billion) deal is expected to double its 4G base stations to about 900,000, boosting its 4G reach in more than 330 cities across China.

Currently, China Unicom is falling far behind China Mobile, the country's largest carrier by subscribers, in both the number of 4G users and base stations.

By the end of 2015 China Mobile had about 1.2 million 4G base stations and its 4G users exceed 312 million.