ZTE has just announced a device that supports both flavors of 4G LTE. Didn't know there were two flavors? Time for a short lesson. Most wireless operators around the world use spectrum that's duplexed, meaning they have a chunk of spectrum dedicated to downloading data, and a chunk of spectrum that's meant for uploading data. This is generally done to reduce interference. GSM, 3G, 4G FDD-LTE, these are all using duplexing technology. But there's another way to transmit data, one that involves taking a massive chunk of spectrum and then using it to transmit data for a few milliseconds, then download data for a few milliseconds. This process of switching between uploading and downloading happens so fast that most people don't notice.
The phone that ZTE announced today, the Grand Era, works on China Mobile Hong Kong's dual TDD/FDD 4G LTE network. Do any other networks use TDD-LTE? Actually, yes. Despite the fact that this flavor of LTE was developed in China, operators in several other countries picked it up, most notably Sprint in America. Their current network uses FDD-LTE, but they're soon going to have Clearwire's 2.5 GHz spectrum. That spectrum will go TDD-LTE.
What does this all mean for consumers? You really shouldn't have to care about any of this at the end of the day because there are so many other things you need to take into account when picking an operator. How's the coverage? How are the real world speeds? How are the prices? T-Mobile showed the world that they can deliver 20+ megabits per second using DC-HSPA+, but you have to be living in a relatively small city. Meanwhile AT&T and Verizon struggle to offer more than 10 megabits per second in the middle of Manhattan, but hey, it's New York City for crying out loud!
Back to the phone for a second, it's your typical 720p screen phone with a dual core 1.5 GHz processor and a gig of RAM. Nothing too exciting.