At least half a million base stations will be installed or upgraded for TD-LTE by the end of 2016, according to a study by ABI Research. TD-LTE is the Time-Division Duplex (TDD) variant of the fourth-generation (4G) Long Term Evolution (LTE ) wireless standard.
"It was only two years ago that nearly every WiMAX operator, including operators with unpaired TDD frequency spectrum, were planning to deploy WiMAX 2," says Aditya Kaul, practice director, mobile networks at ABI Research (New York). "Today, almost all of them have switched plans and are deploying TD-LTE  instead."
WiMAX operators today are generally offering fixed WiMAX service based on the IEEE 802.16d specification, or mobile WiMAX service based on IEEE 802.16e. The IEEE 802.16m standard (also known as WiMAX 2) was developed to provide higher data rates and increased capacity and the members of the WiMAX Forum committed to follow this evolution path for 4G.
"A funny thing happened on the way to the forum," says Jim Eller, principal analyst, wireless infrastructure at ABI Research . "Despite starting two years later than WiMAX 2, TD-LTE emerged as a viable alternative."
China Mobile (Beijing, P.R.C.) was the early promoter of TD-LTE technology, as a 4G evolution path for its 3G  network based on TD-SCDMA technology. Other operators, however, saw better advantages in aligning with the global LTE standards, says the research company.
TD-LTE commercial service has been launched in Brazil, Japan, Poland, Saudi Arabia, and other countries. TD-LTE deployments are underway in Australia and Scandinavia and large-scale TD-LTE networks are planned in the United States and India.
The 600-pound gorilla in TD-LTE is still China. China Mobile started its second phase of the TD-LTE Large Scale Trial Initiative (LSTI) in December and it will run until June 2012.
According to Jake Saunders, vice president of forecasting at ABI Research, "China Mobile announced plans last month to install an additional 10,000 to 20,000 TD-LTE base stations in 2012 and perhaps another 60,000 in 2013."