LG Uplus, the nation’s smallest telecom carrier, said Monday that it will pour an additional 955.6 billion won into building network infrastructure for the Long Term Evolution service this year.

The figure represents about 24 percent of its equity capital, and is an increase from the 1.7 trillion won invested in 2011.

The company will step up efforts to complete the nationwide coverage of LTE by March as planned, earlier than rival companies SK Telecom and KT Corp.

Within the year, it aims to secure 4 million LTE subscribers.

“When the nationwide coverage of LTE is completed, the number of LTE subscribers will soar explosively,” said a LG Uplus official.

The telecom firm also said it widened net loss in the fourth quarter of last year due mainly to a surge in marketing costs paid to attract subscribers for the new LTE service.

Its sales during the October-December period increased 3 percent to 2.45 trillion won ($2.17 billion) compared to the previous quarter, while the operating profit dropped 57.3 percent to 4.5 billion won, according to its annual earnings report.

Industry sources said a surge in marketing costs following the beginning of LTE handset sales in July may have driven the overall costs at the company. In the fourth quarter, the company spent 407.5 billion won in marketing activities, up 15 percent from the previous quarter.

The average revenue per user, or ARPU, however, increased for three consecutive quarters with the fast adoption of more expensive high-end handsets here. The company secured 3.84 million smartphone users out of its 9.39 million cumulative subscribers.

For the whole of 2011, the company posted a net profit of 84.7 billion won, down 85.2 percent from a year earlier. Its 2011 revenues increased 8.9 percent to 9.25 trillion won while operating profit declined 56.4 percent to 285.7 billion won due to a one-off payment of corporate tax in 2010.

By Lee Ji-yoon (jylee@heraldcorp.com)