Broadcom chip eases location tracking's thirst for power

IDG News Service - Broadcom says it's invented a chip that can tell your phone where you are all the time without quickly draining your battery.

The BCM47521 chip, which will be demonstrated at Mobile World Congress next week, should make it easier to use apps that react to the user's location, said Richard Najarian, senior director of business development for GPS at Broadcom. That could include tools that mute an employee's ringer when they enter the office, send a text message when a child leaves school grounds, or tell a retailer when a loyal shopper is near a store.

In the past, such apps have drained batteries too much to be used all the time, Najarian said. Constantly checking the phone's location now consumes hundreds of milliamp-hours per day from phone batteries that typically store about 2500 milliamp-hours of energy, he said.

The BCM47521 slashes that power use by about 90 percent, according to Broadcom. The company's engineers achieved the savings by integrating functions inside the chip that previously required a call to the phone's general application processor and memory, Najarian said. Starting up a 1.5GHz CPU in a smartphone every time an app wants to know the phone's location comes with a cost in power.

Broadcom says its new chip is useful for more than geofencing. It has two modes for different uses, with different levels of precision. The background geofencing function only uses satellite-based systems such as GPS (Global Positioning System) and the Russian GLONASS service. Those are accurate enough for most geofencing apps, which typically track location down to the nearest 50 meters, Najarian said.

For apps that demand greater accuracy, such as turn-by-turn navigation, the BCM47521 has a high-precision mode that can tap into Wi-Fi and inertial sensors in the phone. Those can give more information about precise location and which way you're heading. But to get that data, the chip still has to go into the application processor and main memory.

Phones built with the BCM47521 should hit the market by the second quarter of this year, according to Broadcom.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com