China Mobile Communications Corp, the world's largest telecom carrier by subscribers, said it has already launched the second phase of its fourth-generation (4G) mobile network trial in six Chinese cities, and hopes to complete the new trial by June next year.

The new large-scale TD-LTE network trial began in October, following the completion of a nine-month first-phase trial at the end of September, said Li Zhengmao, an executive vice-president of China Mobile, at an industry summit in Hong Kong on Tuesday.

During the previous trial, China Mobile invested about 600 million yuan ($94 million) and, with partners, built 850 base-stations in six major Chinese cities, including Shanghai, Shenzhen and Guangzhou, Li said. "The result was successful and in line with our expectations."

Investment and the number of new base-stations in the next trial phase will be greatly increased, said Li, who did not reveal exact figures.

However, the number of pilot cities will be restricted to the previous six, according to China Mobile. Bill Huang, general manager of the China Mobile Research Institute, said the company will "do more work" to construct high-quality 4G networks in those cities.

In addition, China Mobile will set up a TD-LTE demonstration network in central Beijing in 2012, so major customers and partners can experience the service, said Huang.

The second-phase trial will also address compatibility problems among different equipment makers, because China Mobile may include input from 11 telecom infrastructure vendors in the new trial.

Meanwhile, Li said the company will make efforts to promote the convergence of the different systems, known as LTE TDD and FDD, which will allow users to move easily between the two main 4G networks.

TD-LTE technology, China's variation on LTE TDD, is a homegrown 4G standard promoted by China Mobile. Its predecessor, the TD-SCDMA 3G technology, failed to attract enough industry partners and has limited terminal selection and a low user base.

In an interview with China Daily in September, Wang Jianzhou, chairman of China Mobile, said the globalization of the TD-LTE technology is already a reality.

By October, there were 33 TD-LTE trial networks globally. Meanwhile, Saudi Arabia has launched two commercial TD-LTE networks this year and more than 10 operators have plans to deploy the system commercially.