Samsung announced the original Galaxy S and Galaxy S II during Mobile World Congress in 2010 and 2011, respectively. In 2012, Samsung decided to stage a separate event to reveal the Galaxy S III. That event took place in London in May, more than two months after the mobile industry's biggest trade show.
The GSIII went on sale late in the second quarter and eventually became the best-selling smartphone during the third quarter. It ranked third during the fourth quarter, behind the Apple iPhone 5 and iPhone 4S.
This year, Samsung is again staging a separate event to launch its most important smartphone for the next 12 months. Samsung's move highlights a trend wherein companies skip the larger trade shows where it is more difficult to steal the spotlight. By scheduling its own Big Reveal, Samsung will be able to own the spotlight for a day or two.
[ Samsung is bringing out a lot of new products. Read Samsung Galaxy Note 8 Tablet: iPad Mini Rival. ]
So, what's expected in the Galaxy S IV? Samsung isn't saying. There have been no leaks of the device and not many hints as to what features it may include.
Don't expect the screen to get much larger. The GSIII has a 4.8-inch display, and the GSIV will likely stick with that size. Samsung wants to be able to differentiate the GSIV from the Note II, which has a 5.5-inch screen. The GSIV's display will improve to full HD resolution.
The GSIV will use the latest home-grown Exynos processor from Samsung, and will have better cameras, though not necessarily higher-megapixel cameras. The GSIII has an 8-megapixel shooter. It would not be surprising for Samsung to stick with an 8-megapixel sensor and to improve the camera on other ways.
Perhaps the biggest question mark concerns the GSIV's design. Will Samsung stick to the same design language it has used for the last year, or begin anew with a changed look? Samsung has introduced devices using the GSIII design language for the past year, and as recently as this past weekend (the Note 8).
However, Apple has set overall expectations for smartphone hardware quality pretty high. A long-standing complaint about the Samsung Galaxy S series has been the cheap materials use to build them. It would behoove Samsung to improve the quality of the GSIV, but Samsung hasn't yet tipped its hand.