The government is concerned about the long-term economic impact of using the 900MHz spectrum for railway projects and may consider other spectrum ranges for use instead.
The auction of 900MHz licences scheduled for Aug 18 is likely to be aborted because no companies are expected to submit bid documents and place a bank guarantee by tomorrow.
A key issue is uncertainty with regard to the responsibilities of the winners.
The conditions state that licence winners must be solely responsible for any and all interference with upcoming railway projects, both on the 850MHz and 900MHz bands.
A government source who asked not to be named said that representatives of the Finance Ministry have talked with the telecom regulator about the possibility of the government's high-speed train project using spectrum ranges other than the 900MHz, which was already allocated, to avoid a loss of economic opportunity in the long term.
"If the government decides to reshuffle the spectrum range, the terms of reference of the high-speed train project will have to be amended," the source said. "The 400MHz spectrum range may be an alternative for the high-speed train project."
In June 2017, the board of the National Broadcasting and Telecommunications Commission (NBTC) approved 10MHz of bandwidth on the 900MHz range and 20MHz of bandwidth on the 400MHz spectrum range for the high-speed train project.
The approval came after the Transport Ministry had asked the NBTC to allocate the 900MHz range for the train project.
Under the approval, the two spectrum bands would be used by 2020.
The 900MHz spectrum is part of the mobile concession for Total Access Communication (DTAC) under CAT Telecom. The concession expires next month.
The internal communication system via wireless technology on the high-speed trains will be conducted under Global System for Mobile Communications-Railway (GSM-R) technology.
GSM-R is the international standard for wireless communications systems between trains and railway signalling and control centres.
The 400MHz spectrum range is used for communication radio systems or trunk radio systems.
The government source said China's train system uses the 900MHz range for signalling and control centres while Japan's system uses the 400MHz range.
Earlier, Rajiv Bawa, DTAC's chief of corporate affairs and business development, insisted that it would be difficult for DTAC to participate in the 900MHz bid if the conditions remained in place.