The upgrade, mainly of core transmission lines, wireless GSM network (System for Mobile Communications) and 3G (Third Generation network), focused on the central and southern region, the company said.

"While the higher capacity of core transmission will help us serve the rising number of subscribers, an upgraded wireless network and data bandwidth will better serve our Smartphone users" said MobiFone's deputy director Nguyen Dang Nguyen.

MobiFone said the upgrade was technically backed by international network solutions firm Nokia Siemens Networks.

According to Tanat Techatanabaht, general director of Nokia Siemens Networks Viet Nam, the project will help MobiFone solidify its position in the fiercely competitive market while raising the company's revenue from the value added services.

MobiFone, a subsidiary of Viet Nam's largest telecom service provider VNPT (Viet Nam Post and Telecommunication Group), currently accounts for some 29 per cent of the country's total 120 million mobile subscribers.