It's really early for this, and it's nothing concrete or solid.
But ◆M4ApJwbK/w, a somewhat legit spoiler provider, posted on 2ch that the concept is based around tablets and smartphones. Of course, it's still very early, so there's a possibility that it might change.
Again, ◆M4ApJwbK/w has posted spoilers that ended up true.
Here's a translated post by him.
Kamen Rider: Keitai Sousakan