Advanced Info Service (AIS) has updated its plans for rolling out a nationwide 3G mobile network, announcing that it intends to invest THB20 billion (USD610 million) in developing third-generation voice and data services in the 2100MHz spectrum band, reports the Bangkok Post. The plan calls for deploying 3G base stations nationwide, focusing on Bangkok and provinces with high population density and high demand for mobile broadband services. AIS would not need loans for the expansion as it had enough cash, according to the company. Thailand’s cellular market leader is also playing down the importance of last month’s launch of its W-CDMA/HSPA ‘3GSM’ service in Chiang Mai, which only has a few hundred users, saying that the upgraded 900MHz network will be used for voice-based traffic instead of data when the National Telecommunications Commission (NTC) eventually issues 2100MHz UMTS operating licences. AIS is currently awaiting approval by the NTC to import equipment for 900MHz 3G services in Bangkok and another 20 major provinces. AIS does not expect significant revenue from 3G in the short to medium term as the ratio of data usage to voice in Thailand is still small.