@elyasfeyzollahi: You can start by telling us what model of Galaxy S4 you have by entering download mode and reading the model number given in the upper left corner of the screen. Also, tell us what country you live in.
With that said, if your model number is I9500, forget about LTE. You can't enable it because you don't have the hardware to support it.
With that said, if your model number is I9500, forget about LTE. You can't enable it because you don't have the hardware to support it.