Thailand’s telecoms regulator set the date for the auction of the 1.8GHz spectrum held by the country’s second largest operator dtac for July 2018, two months before the concession expires.

Takorn Tantasith, secretary-general of the National Broadcasting and Telecommunications Commission (NBTC), said the auction is expected to raise a minimum of THB135 billion ($3.86 billion), the Bangkok Post reported.

The reserve price is set at THB3 billion per megahertz and is based on the winning price of the 1.8GHz block sales in last year’s auction, plus inflation. Takorn insisted that the wining prices of the 2018 auction must not be lower than in 2015.

Dtac has 45MHz of spectrum in the 2G band under a concession, which expires in September 2018.

Dtac chief executive Lars Norling told the Post it’s a positive move that the regulator plans an early auction but said it only gives a three-month lead time, which is not enough for network installation. Operators need as much as six months to prepare a network.

The sale of the 1.8GHz spectrum, which is the country’s last spectrum allocated under a concession arrangement, is expected to reduce conflict between the regulator and operators over revenue sharing, the Post said.

Last December market leader AIS won 15MHz of 1.8MHz with a THB41 billion bid and True paid THB39.8 billion. The two companies also each won 10MHz of 900MHz spectrum in January for about THB76 billion.