LEO satellite mobile communication system has become an important branch of global mobile communications system since it proposed.

低轨卫星移动通信系统自从提出以来就成为全球移动通信系统的一个重要分支。

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While the iPhone is offered by carriers around the globe, all of them rely on the Global System for Mobile Communications (GSM) protocol.

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Americans are at a disadvantage when it comes to cell phones overseas, because most of the world uses a GSM (Global System for Mobile Communications) standard, Schukai said.

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In 1993, NTT DoCoMo, Japan's principal mobile-phone carrier, opted for a technical standard called Personal Digital Cellular (PDC), which was incompatible with the Global System for Mobile Communications (GSM), the standard adopted by most of the rest of the world.

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