The Hanoi Times - Vietnamobile will roll out its mobile phone services nationwide next month after finishing network installations and successful trial runs.Vietnamobile - formerly HT Mobile will be the country's fourth GSM mobile services provider after MobiFone, Vinaphone and Viettel.The company has yet to declare its mobile services charges.HT Mobile was licensed by the Ha Noi People's Committee last March to invest in a transformation from Code Multiple Division Access (CDMA) technology to Global System for Mobile communications (GSM). The new company is a joint venture between Ha Noi Telecom and Hutchison Telecommunication.Company bosses have announced they would pump another US$150 million into its initial $650 million investment to cover the cost of the network change.HT Mobile admitted that the major reason for its failure was that it operated a CDMA service, and not the much desired GSM service.Established in Ha Noi in January 2007, the company has o­nly 200,000 subscribers - a fifth of its intended target after a year's operations.In August last year, the network decided to purchase GSM network equipment worth $600 million from Ericsson and China's Huawei. Ericsson provided $450 million worth of equipment while Huawei provided $150 million worth.