Samsung (OTC:SSNLF) is likely to announce the Galaxy Note 4 next week. The giant smartphone, which should feature an enormous screen and built-in stylus, could compete with Apple's (NASDAQ:AAPL) widely rumored 5.5-inch iPhone this fall.

But there might be more to Samsung's latest phablet: An unprecedented partnership with Facebook's (NASDAQ:FB) Oculus could give Samsung's next flagship a unique feature.

An unusual accessory
Samsung is no stranger to accessories: In addition to offering a wide variety of Galaxy smartphones, it sells an equally impressive collection of add-ons -- from cases to charging pads, streaming hubs, game controllers, and everything in between.

But Samsung's Note 4 could launch with its most revolutionary accessory yet. In recent weeks, various outlets, including The Verge and SamMobile, have reported that Samsung will debut its Note 4 alongside a sort of virtual reality headset -- a mask that would allow owners of Samsung's next phablet to immerse themselves in a virtual world.

The phone itself would do the work, while the accompanying mask would keep it firmly attached to the user's face. Paired with Samsung's bluetooth GamePad, the Galaxy Note 4 could take mobile gaming to the next level.

A partnership with Oculus
If so, it could be because of a partnership with Facebook-owned Oculus. The virtual reality company has, according to Engadget, come to an agreement with Samsung to supply the software that would allow its phones to function as a virtual reality device. In exchange, Samsung has given Oculus high definition panels for its own, PC-centric headset. As evidence of this agreement, Oculus' latest product, the DK2, uses the screen from Samsung's Galaxy Note III for its display.

Reports have suggested that Samsung's Galaxy Note 4 will use a higher resolution display than the Note III, which sports a standard, 1080p screen. That seems plausible, especially because Samsung's longtime Korean rival, LG, has equipped its own competing phablet -- the G3 -- with a super-high resolution display. Some critics have rightly questioned the value of offering a progressively higher resolution smartphone screens (at a certain point, the human eye has a difficult time telling a difference), but as a virtual reality headset, those extra pixels could make a significant difference.

Enough to win over buyers?
Ultimately, for Samsung, the value of its virtual reality headset will depend on its ability to move hardware: Will consumers choose Samsung's Galaxy Note 4 over Apple's competing phablet because of its virtual reality capabilities?

It's possible, but difficult to answer. Certainly, gaming is important to handset owners -- as a percentage of the time spent using smartphones, almost a third of it is spent gaming, according to analytics firm Flurry. At the same time, impressions of Oculus' headsets have been nearly universally positive -- Facebook's CEO, Mark Zuckerberg, in fact, was so blown away by the experience that he bought the company for $2 billion.

But the Oculus Rift that Zuckerberg used was attached to a high-powered gaming PC -- not a Samsung handset. At the same time, there have been dozens of Oculus-compatible games announced or released, but all of them have been designed for the PC. If Samsung is planning to launch a virtual reality headset with its Note 4, it must have some compatible software on the way, but it could take quite a while before there's enough apps and games to sway a significant number of buyers.

A different sort of wearable
Nevertheless, if Samsung does debut its Galaxy Note 4 alongside a virtual reality headset, it will open up a new avenue in the smartphone market.

In the past, smartphone owners may have chosen Apple's iPhone because of its operating system, build quality, or ecosystem. They may have selected Samsung's Galaxies because of their larger screens and removable batteries. But in the future the decision could come down to wearables -- which sorts of gadgets will a given smartphone work with?

For the Galaxy Note 4, its defining feature may not be the size of its screen or the quality of its build materials, but rather, its ability to double as a virtual reality headset.