Coming up with titles is hard. I actually never wrote titles for my papers in high school or college until after everything else was done. I needed the inspiration of all of the other stuff to come up with a decent title. Based on the question, it sounds like that part is done already. I do not know what cellphone or cellphone feature that the question has in mind, so I'll have to be a bit broad.
When coming up with a title, you want the title to apply to the topic, not be mundane, and shorter is better than longer because it's generally easier to remember.
My favorite feature of my cellphone is the camera. I know that's not exciting, but I have three little kids, so the camera gets used a lot. It's a camera but it doesn't have a cool title name. I'm kind of partial to "The Time Capture Device." It sounds way more scientific than "camera," but the problem is that it is longer than the actual name. Maybe "Photo Cannon" is better.
Regardless of the feature that you are trying to provide a title for, don't be afraid to be silly with the title. I've often found that starting out with silly names often leads to titles that are quite creative.