T nor Cellco has LTE. its 3.5. and the LTE standard they're using isn't even a "standard" of LTE yet. LTE won't be out for at least another 2 years.
I believe you have on mind "LTE Advanced". No carrier in the world currently offers 4G network as before ITU-T "changed its mind" and redefined 4G to include LTE, Wimax and HSPA+.