Thai regulator NBTC has rejected a request from mobile operator Dtac to be allowed to deploy a 4G service based on its existing unused 1800-MHz spectrum.
Dtac has access to 50MHz of 1800-MHz spectrum under its existing 2G concession arrangement with state-owned CAT Telecom, which is due to expire in 2018.
But the NBTC has declared that approving the proposal to use an unused portion of the 1800-MHz spectrum would violate the concession agreement, the Bangkok Postreported.
The regulator stated that Dtac must present formal evidence demonstrating that CAT and Dtac have mutually agreed on the 4G proposal, noting that it has no authority to allow companies to violate the terms of concession agreements.
Dtac currently uses 25MHz of its 1800-MHz spectrum for 2G, and after returning 5MHz of the remainder for the 4G auction last year now has 20MHz left unused.
But securing the go-ahead from CAT will require the companies to negotiate on a revised revenue sharing agreement. This threatens to delay Dtac's 4G rollout, which would potentially be a significant disadvantage if rival operators are able to deploy LTE services more rapidly.