There was a time a couple of years ago when the winner of the race to build the best 4G network was still up for grabs. One strong contender at the time was WiMAX. Back in 2006, Sprint and Clearwire did a joint WiMAX venture, investing a significant amount of money trying to build out their WiMAX network.
The two companies had a couple of year’s head start over their competitors. They knew the technology wasn't perfect, but they thought that, with a couple years’ lead, they could get a jump-start on the competition and fix any issues along the way. The problem was that customers didn’t love WiMAX, coverage wasn’t optimal and the ecosystem failed. While it did offer more speed, it wasn’t that much faster and you often couldn’t find it where you needed it, either because the network wasn’t there or it didn't have the best building penetration.
Nonetheless, Sprint and Clearwire were able to deploy WiMAX in 50 to 75 markets. But for a technology to flourish and grow, competing companies have to adopt it and an ecosystem of vendors, suppliers, and manufacturers must come into being. The opposite happened with WiMAX when operators early on signaled their interest in moving to LTE.
Sprint already offers 4G-LTE using frequency division duplex (FDD). When it converts the WiMAX spectrum to 4G-LTE it will use time division duplex (TDD). FDD uses fixed uplink and downlink channels. If you set aside 10 megahertz for upload and 10 megahertz for download, you're always limited to 10 megahertz of frequency for each channel.
In TDD on the other hand, you can re-purpose your uploading bandwidth for downloading, and vice versa. If you need to download a large amount of data, you can open up the channel and access the entire 20 megahertz for faster download. This kind of flexibility makes TDD more efficient.
As 4G-LTE technology advancements like these continue to advance, 4G-LTE will gain even more adoption as an enterprise-grade network capable of running business-critical applications.