Let's face it, the design of modern smartphones is almost identical, there's a screen on the front, a camera on the back and some hardware buttons that may include a Home button on the front and some around the device, typically to control the volume of the media files or ringtones and a power button to lock and unlock the device, some may even include one to take pictures. Some manufacturers create the illusion of making slimmer devices than they actually are by making them really thin at the edges and placing the internal components at the middle, so they are thicker in that area and while it could make their design more ergonomic, placing the buttons around the edges got more difficult, so they are located on the back.
Now, Samsung has registered a patent to further expand the idea of having more controls without requiring extra hardware buttons. The patent can be found in the U.S. Patent & Trademark Office documentation as it was registered back in January but was published only recently. It includes some areas of the edge of the device, called sensor pads, that would be sensible to the touch providing a sort of invisible buttons. They include 3 of these buttons on each side and they can be configured to work in a certain way for the app that uses them. Let's say you're in the camera app, the shutter button could be one of them depending on how the phone is being held or you could program the 6 buttons to work with the most used settings such as the flash, HDR, self-timer and so on.
These new controls can be particularly useful in mobile games, because even when smartphones have brought a whole new way of playing thanks to all the sensors they include and on-screen buttons, the buttons on the edge would allow the screen to be visible at all times or adding more ways to control the elements on the screen. Of course, this being a patent, there's no way to know when or if this will be implemented, but it seems to be a useful way to take advantage of that area that seems kind of wasted.