Wireless Systems Design

Single Chip Brings A-GPS To Mobile Phones

When the Enhanced 911 (E911) mandate was put into place by the Federal Communications Commission (FCC), both carriers and device makers fought to cost effectively implement a service that seemed to offer little return on investment. Since that time, the industry has witnessed the emergence of consumer-driven, location-based services. Thanks to applications like gaming or point-to-point navigation, the popularity of such services has grown. Now, Global Positioning System (GPS) technology is targeting handheld devices for both E911 adherence and the chance to provide revenue-generating services. To help designers reach that goal, Infineon Technologies AG (www.infineon.com) and Global Locate (www.globallocate.com) joined to develop an Assisted-GPS (A-GPS) chip for mobile telephones, smart phones, and PDAs.

The new Hammerhead chip promises to bring GPS functionality to mobile phones (FIG. 1). The chip will enable location-based services like emergency assistance and personal navigation in deep urban canyons, moving vehicles, and even indoors. To bring this chip into existence, Global Locate offered system-level expertise in conjunction with its knowledge in baseband design, GPS signal processing, and control software. Infineon contributed in the areas of radio-frequency design, system integration, process technology, and manufacturing.

Through their efforts, the companies have spawned a chip that promises to detect a GPS signal that is 1000 times weaker than the normal "open-sky" signal outdoors. In addition, all aspects of the chip's design have been optimized for mobile handsets. While consuming very little power, the Hammerhead boasts robust performance. And at 7 2 7 mm, it's no larger than a key on a mobile phone's dialing pad.

In mobile phones, it's been difficult to implement location-based services that use GPS. The weak signals are difficult to detect indoors, inside moving vehicles, and in other environments where mobile phones are commonly used. Even outdoors, a mobile phone's traditional GPS receiver can take several minutes to receive satellite navigation data and compute an accurate position. As an alternative, Assisted-GPS uses the cellular connection to transmit the remotely collected satellite navigation data from the base station to the mobile phone. As a result, the user should be able to pinpoint his or her exact position in seconds (FIG. 2).

Infineon and Global Locate will jointly market the Hammerhead chip. The companies expect to have samples available in the first quarter of next year.

TAGS: Mobile
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