3G & 4G
First, the basics: The “G” stands for generation, meaning 4G is the most current generation of cell phone network coverage and speeds. 3G technology created the first networks fast enough to make smartphones practical. Before that, they were too slow to allow you do all the things that make smartphones great, like streaming videos, surfing the web and downloading music.
But it’s 4G that’s really allowed smartphone technology to spread its wings. That’s because it’s much, much faster than 3G. So when you want to download a new game or stream a TV show in HD, you can do it without buffering and lags that make the experience not worth the wait.
4G is pretty much everywhere now, but even if you happen to be in a place that only has 3G, your phone will automatically switch to 3G so you’ll experience no call problems—just slower Internet speeds.