National studies low-power WiFi for handsets

National studies low-power WiFi for handsets
SANTA CLARA, Calif. — Researchers at National Semiconductor are studying the feasibility of a low-power version of 802.11 that would be suitable for cell phones and PDAs. The company is not sure whether it will field such products, but executives at an informal roundtable discussion here said the need is real.

"Bluetooth has to step up to higher bandwidth and become more networkable or 802.11 has to become more power friendly — and probably both will happen," said Mike Polacek, general manager of National's imaging group which is sampling CMOS sensors to cell phone makers.

A handset-friendly version of 802.11 should use single digit milliwatts of power when in standby or receive mode and "a few tens of milliwatts" in transmit mode. The power savings would come at the expense of data rates or transmission distances, said Peter Henry, vice president of portable power systems at National.

Such a device could replace a Bluetooth headset, however, "it's not clear that's going to happen," said Henry. "Bluetooth is gaining market momentum" and 802.15.4 also has a shot at handheld networking, he added.

Currently, National sells a Bluetooth module but is not selling any 802.11 or Zigbee chips. The later are under investigation in an RF R&D lab at the company, said Henry.

The combination of low power and high bandwidth is key as cell phones take on greater imaging jobs, said Polacek. His group is now sampling 1.3 megapixel CMOS sensors that he expects will appear in cell phones next year, hoping to replace CCD components from Sony and others that now widely used in phones.

"We had representatives from a major cell phone maker in here just the other day and they were very concerned about the whole imaging signal path for next-generation phones," Polacek said.

Shipments of cell phones equipped with cameras have outstripped sales of digital cameras this year, he added.