4G LTE is rapidly taking over 3G as the wireless network standard globally. Finding an LTE device compatible with bands supported by your carrier and region is a headache in itself. In order to help reduce confusion, Sony has posted up an LTE roadmap.
The roadmap is very detailed and should make it a lot easier for those looking into purchasing an LTE compatible Xperia smartphone. While the roadmap is quite lengthy, its easy to spot which handsets support LTE and on what mobile network globally. You can read the full roadmap here.
The full list of LTE supported Xperia smartphones are as follows:
Keep in mind that despite these being LTE supported devices they will not necessarily all work in the same area. It often has to deal with the carrier's coverage, which many will find to be abysmal. Verizon, who has most of the US covered with LTE, does not sell Xperia smartphones. That leaves you with AT&T, as Sprint or T-Mobile does not carry Xperia devices.
AT&T's coverage is fairly good, but does not cover nearly as much as Verizon yet. If you're looking to grab a Sony device off of AT&T, head on over to Amazon Wireless. Their Xperia TL is a mere $0.01 as opposed to $50 off of AT&T's own website.