Apple's unveiling of its iPhone 5S is expected Sept. 10, just six days after Samsung's launch in Germany of its next Galaxy gadget, probably a Note III smartphone-tablet.

While the two products aren't directly comparable, the timing of the two announcements is another reminder of the intense rivalry between Apple and Samsung. The South Korean device maker is clearly putting pressure on Apple to produce exciting new products at each launch and to differentiate iPhones from a wide range of Android phones made by Samsung and others, analysts said.

"Even though the [new Samsung and Apple] phones aren't directly comparable, Samsung's launch timing was designed to steal attention away from Apple's new iPhones," said Patrick Moorhead, an analyst at Moor Insights & Strategy. "Samsung didn't want to give Apple an unencumbered path to receive all the week's attention."

Cupertino, Calif.-based Apple hasn't confirmed its launch date or what it will launch, although AllThingsD cited unnamed sources sources saying the next iPhone will be launched Sept. 10.

Apple may also roll out a cheaper iPhone, according to various reports, possibly named the iPhone 5C, with the C referring to different colors of plastic cases.

Samsung all but said recently that it will launch a Galaxy Note IIIsmartphone- tablet, putting it in the category commonly called a phablet. Analysts still count the Note devices in the smartphone group, however. The device is expected to have a writing stylus that reports say will work on a 6.3-in. touchscreen, compared with the current iPhone 5's 4-in. screen.

Samsung makes a number of smartphones, and the Galaxy S4 is the closest to the iPhone 5. The next-generation successor to the S4 is expected next year.

Globally, Samsung sells more than double the number of smartphones as Apple, but in the U.S., Apple still has sizable marketing allure over the Seoul-based Samsung since Apple is based in California and created the first idyllic iPhone six years ago, analysts said.

Samsung shipped 73 million smartphones in the second quarter, making it the largest Android maker by far, while Apple shipped 31.2 million, iPhones, IDC said last week.

Jeff Kagan, an independent analyst, said Samsung, with its Sept. 4 Galaxy launch in Berlin, stands to "steal a bit of thunder from Apple, but does it really matter? No....There's a difference between an Apple fan and a Google Android fan -- most have a definite preference."

Still, Samsung and Apple are clearly locked in "an all-out battle for supremacy in the smartphone handset market," Kagan added.

How important will the two September launches and early weeks of marketing be in the continuing Samsung-Apple competition?

"Consumers are very quick to make up their minds and early marketing is key," Moorhead said. "Both Samsung and Apple want to come out of the starting blocks strong and establish their new product's position. It is critical for Apple to do so with their new fifth-generation phones."

Apple faces at least two challenges with its next launch, he said. "In established regions [such as the U.S. and Europe], Apple needs to re-create the sense with consumers that iPhones bring something very different to the table," Moorhead said. "Android has caught up in most or many ways, and Apple doesn't look different. In emerging regions, Apple's high price and limited distribution are issues for Apple."

If Apple can't successfully address such challenges, it risks losing more global market share, Moorhead said.

"After the launch, it's about how differentiated your products are," said Jack Gold, an analyst at J. Gold Associates. "I think many consumers are now getting saturated with feature creep and unable to tell the real differences with most major brands. Things like Siri ... and early iPhones were revolutionary and easy to differentiate. That's Apple's real challenge: How to differentiate and get user upgrades in a very crowded and undifferentiated market."

Gold also raised a question many others who track the mobile phone industry have: How many consumers will continue to buy high-end smartphones when they aren't that much better than the cheaper ones?

Apple faces the challenge in both emerging and mature markets of getting prices lower, Gold said. "If there's good enough technology priced well below iPhones, many customers will opt for that choice, as has largely been the case with Android," he said. (The iPhone 5C is rumored to sell for $99 on a two-year contract plan, less than half the cost of a new traditional iPhone.)

Gold said that rumors of a new iPhone 5S with a fingerprint chip and a bigger screen that would sell alongside cheaper iPhone 5C models might not be enough to differentiate Apple in the crowded market.

"The real threat to Apple comes from not offering enough innovative features in the next iteration of the iPhone to matter to consumers," Gold said. "Apple has lost quite a bit of market dominance, driving largely by others catching up or even surpassing some iPhone features. Can Apple get the mojo back? That's the real question."

This article, Apple-Samsung rivalry intensifies with September device launches, was originally published at Computerworld.com.

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed. His email address is [email protected].

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