Following the approval by Thailand’s telecoms regulator for the return of 5MHz of unused 4G airwaves, Suphachai Chearavanont, CEO of operator True, has suggested that the 30MHz of available 1.8GHz spectrum be divided into three blocks of 10MHz for the auction in November.

Last week the National Broadcasting and Telecommunications Commission (NBTC) reportedly approved dtac’s offer to return the spectrum, which it insisted would have to come without conditions and compensation. The spectrum is part of a concession with state-owned CAT Telecom that isn’t due to expire until 2018.

The NBTC has said it will split the 30MHz into two blocks of 15MHz, but Suphachai said that offering three 1.8GHz licences would allow the country’s top three mobile operators to stay competitive, as each would have a shot at the spectrum, the Nation reported.

Suphachai has previously said that operators need at least 20MHz to offer 4G service effectively. Dtac has stated that blocks of 5 or 10MHz are better suited for the auction.

The return of the 5MHz depends on if CAT can transfer the spectrum to the NBTC before it finalises its auction plan.

In a related developed, the NBTC’s Telecom Committee is expected to consider the draft proposal of the 1.8GHz auction regulations, which includes a 60MHz spectrum limit for each of the country’s operators, the Nation said.

The regulator last month proposed introducing a 60MHz spectrum cap on the amount of spectrum an operator can hold to encourage newcomers to enter the market.

The country’s long-awaited 4G auctions, delayed by more than a year since the military coup last year, will also include the sale of 20MHz of 900MHz spectrum in December.

The NBTC said it will hold public hearings on its 1.8GHz auction plan from 18 July to 17 August.