I mean, your smartphone already knows how to talk on 600 megahertz, 700 megahertz, 800 megahertz, 1.7 gigahertz, 1.9 gigahertz, 2.1 gigahertz, 2.4 gigahertz, 3 gigahertz, 5 gigahertz, 6 gigahertz, etc. I see absolutely no reason it would be unable to talk on 915 megahertz.
It used to! I think old analog cell phones were on that band.