Samart Corporation will likely be awarded trial fourth-generation service on TOT's 2100-megahertz spectrum, a move that will pave the way for commercial 4G service in a partnership model.
"The 4G trial is expected to take place this month," said Youngyuth Wattanasin, TOT's acting chief executive.
Samart recently proposed installing long-term evolution (LTE) equipment as part of TOT's 3G trial.
The 4G LTE trial on TOT's 3G first phase will be from 100 sites.
Mr Youngyuth said if the market response is good, then TOT will move forward and introduce the service commercially.
TOT hired SL Consortium, which includes Samart and Loxley, to install 5,300 base stations for its first phase at a cost of 15.9 billion baht.
That first phase is scheduled to launch commercially on Feb 22 with 4,000 base stations, mainly in Bangkok and major provinces.
All 5,300 base stations will be completed in May as planned, said Mr Youngyuth.
TOT signed contracts with five mobile virtual network operators (MVNOs) to provide service during the first phase - Samart I-Mobile, Loxley, IEC Technology, 365 Communication and M Consult.
MVNOs do not have their own network but rather lease bandwidth from network operators to offer cellular service.
TOT is still specifying the final details for the second phase, which will require an additional 12,000 to 15,000 base stations nationwide, mostly in locations owned by government agencies without co-site network partnerships from private operators.
In a related development, the State Enterprise Policy Office last Wednesday approved in principle the survival plans for TOT and CAT Telecom.
A meeting chaired by Deputy Prime Minister Kittiratt Na-Ranong gave 90 more days for the two agencies to provide additional details and resubmit their proposals for consideration.
The four unclear areas are plan implementation, funding sources, strategic planning and human resource management.
Mr Youngyuth said TOT will finalise details of its second phase and resubmit the proposal within 90 days.
Previously, TOT and CAT were set to rent their telecom-tower infrastructure to companies that won licences for digital TV, as well as 3G and 4G services.
Their survival plans must detail how they will move forward after their mobile concessions end.
TOT has three private telecom concessions - one with Advanced Info Service that ends in 2015 and others with True Corporation and TT&T that expire later.
CAT's concessions with Digital Phone Co and True Move will end this September and with Total Access Communication in 2018.
Moreover, the two state enterprises can no longer book concession-related revenue in their financial statements from after this year.