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A year to the day after first unveiling the Pixel smartphone, Google will launch the next generation of the would-be iPhone killers in San Francisco.

Also expected from the Mountain View tech giant are other new gadgets, with most speculation revolving around at least one virtual assistant for the home, to compete against the recently bolstered lineup of virtual-assistance devices from Amazon.

The event is important for Google, which last year took two giant steps into the hardware with a virtual assistant to rival Amazon's "Echo" and the Pixel phones to go up against Apple's iPhones.

The first Pixels, launched last year, start at $650 for a device with a 5-inch screen and $770 for the 5.5-inch screen.

With the , Google will continue to seek inroads against Apple's iPhone dominance. Success will depend on broadened reach and unique phone-based offerings including augmented reality (AR), which can overlay real-world imagery with graphics, sound, video or data, said Moor Insights & Strategy analyst Patrick Moorhead.

"To gain market share against Apple, Google will need to bring more differentiated features like world-view AR to the table and also significantly increase carrier and country distribution," Moorhead said.

Although Google's Android operating system for phones covers some 89 percent of the market, only about 2.8 million of the company's house-made Pixel phones have been sold since their October 2016 unveiling, according to research firm IDC. Apple's iPhone 7 and 7 Plus were released about two weeks before the Pixels, but by July, about 48 million of them had been sold in the U.S. alone, according to Consumer Intelligence Research Partners.

In September, Apple unveiled three new phones: the iPhone 8 for $700 with a 4.7-inch screen; the 8 Plus for $800 with a 5.5-inch screen; and the iPhone X for $1,000 with a 5.8-inch screen.

To amp up its Pixels and other hardware, Google is spending $1.1 billion to buy a unit of HTC, a longtime manufacturing partner. The deal gives Google the HTC team that helped build the first Pixels, plus access to intellectual property, the companies said.

Google has also set itself up against Amazon with the $129 Google Home virtual-assistance device, launched in November. The market for these devices is expanding rapidly - eMarketer projected in May that nearly 36 million Americans would use one at least once a month, a 129 percent jump over last year. But the Home still trails far behind Amazon's flagship virtual assistant, the "Echo," which eMarketer predicted would take 71 percent of the market this year, compared to 24 percent for the Home.

The market-intelligence firm said it expected Amazon's market share for the gadgets to decline slightly in coming years as Google's share grows, but it also said Amazon would "remain the dominant player in the category for the foreseeable future."

Apple, however, is expected to bring to market in December its $350 "HomePod" virtual assistant, which will mean more competition for Google and Amazon.

While leaks have led to rumors about virtual-assistance devices to be unveiled by Google, one appears to have come via an unusually credible source. Tech website 9to5Google reported that Wal Mart, in an apparent mistake, had posted a pre-order ad for a $50 "Google Home Mini," a round, fabric-covered . By mid-morning, the ad appeared to have been pulled.

Amazon recently expanded its offerings, announcing in late September upgraded versions of the Echo for $100 and "Echo Plus" for $150, along with the new "Echo Spot" for $130.

Moorhead said he expected new Home devices from Google, virtual assistants turbo-charged with Google's artificial intelligence (AI) software.

"I do believe Google can catch Amazon," Moorhead said. "Google's AI is superior to Amazon's."