Samsung plans to introduce a spruced up version of the Galaxy S4 called the Galaxy S4 LTE - Advanced according to Sammobile and other sources.  The 'advanced' version of Samsung's flagship will be introduced alongside the Galaxy S4 Mini as well as the Galaxy Zoom.   It will feature advanced LTE capabilities and be the first phone to run on Qualcomm's flagship Snapdragon 800 SOC running at 2.265GHz.   The Snapdragon 800


In other words this will be one monster of a phone performance-wize.  There's no word on pricing or if the phone will differ physically from the standard S4.  A benchmark shown above was detected showing the phone being tested.  Other specs leaked are that it will have an Adreno 330 GPU and a 2600mAh battery.