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Here's what to expect from the two events.
On Wednesday Samsung is expected to show off its Galaxy Note 4 smartphone, or phablet.
Last month the company sent out invitations to the event, which will be hosted simultaneously in Berlin, Beijing and New York. Samsung didn't reveal too much in the announcement, but hinted in that the company would be unveiling its Note device.
One of the key features of Samsung's Galaxy Note devices is its large screen size compared with those of competitors. The original Note device had a 5.3-inch screen; the Note 2 featured a 5.5-inch screen and the Note 3 was 5.7 inches. It's speculated that the Note 4 could be as big as 5.9 inches if it follows the same pattern, although it has also been reported that the phone will keep its predecessor's dimensions.
To put that in some perspective, the iPhone 5S has a 4-inch display screen. Apple, though, is expected to make a push to compete with larger smartphones by releasing two bigger iPhones next Tuesday at its company event.
"This is significant because it's the first time Samsung will be releasing a phablet at same time Apple is likely releasing a phablet as well," said J.P. Gownder, a vice president and principal analyst at Forrester.
Gownder said that while Samsung has so far dominated the phablet space around the world, Apple may present some serious competition, especially in the U.S., where phablets have not taken off as much.
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Besides its big size, the Galaxy Note is also known for its signature stylus, which can be used like a pen to write on the screen. Samsung has already released a few teasers for the new device, where it hints that the stylus may also have some significant improvements.
Some of the upgrades in the new device may not be that obvious, Gownder said. According to the Korean Times the phablet may also feature a more curved OLED screen, improved sensors and improved front-facing and back-facing cameras. And like Samsung's Galaxy S5, the new Note device may also feature a waterproof design.
"Some of the rumors suggest that there are elements that need to be seen in person so it's hard to determine whether or not this will be a slam dunk yet," Gownder said.
The company may also show off its virtual reality headset, which was developed with Facebook's Oculus as well as its new 3G-enabled Gear S smartwatch, which it announced late Wednesday, according to a PC Advisor report. Previous models of the smartwatch were not 3G enabled.
As for Microsoft, the company will be getting on the selfie bandwagon when it shows off what is expected to be its new smartphone at an event in Berlin on Thursday.
The device, rumored to be the Nokia Lumia 730, has been nicknamed the "selfie phone" because it's expected to feature a high-quality, self-facing camera. The phone is expected to have a 4.7-inch HD display and come in two models—one that supports 3G for emerging markets and one that has 4G LTE capabilities, according to multiple reports.