In the quest for a truly mobile device, we’ve managed to cut the phone cord and the Ethernet cable. But the power cord? Well, that’s still a problem. While some innovators are working on better batteries and alternative power sources, such as methanol fuel cells and motion, investing in expensive power sources without paying attention to device efficiency is sort of like buying a closet full of new suits just before going on a diet.
Earlier this year, we looked at a few of the reasons why mobile devices power down quickly, among them gorgeous displays, cold weather, and needy chips and applications that keep the processor hopping even when your device isn’t in use. One such culprit is Wi-Fi, something chipmakers have long recognized and are now responding to with low-power offerings. While they won’t all keep your iPhone running longer, they could play a role in boosting the efficiency of a growing number of new devices.
Letting sleeping dogs lie
In most of the how-to’s littered around the web on extending mobile battery life, a top recommendation is to disable Wi-Fi when it’s not actively being used. That’s fine for some users, but for anyone interested in mobile VoIP applications or any of the social applications that use Wi-Fi to pinpoint their location, having Wi-Fi continuously enabled is a must-have.
One solution is to reduce Wi-Fi’s power consumption when it’s inactive. That can be done using Atheros’s AR6002 family of low-power Wi-Fi chips, which launched last year. The AR6002 chips, which are beginning to appear in handsets made by both LG and HP, operate a lot more autonomously than previous generations of Atheros chips, offloading some of the simple operations from the host processor onto the Wi-Fi chip’s own processor.
For example, Wi-Fi, even when it’s not actively transmitting data, is constantly polling for the presence of a network, using an assist from the host processor. While most manufacturers have reduced the power required to perform this polling function, Atheros says its chips do one better. Instead of waking up the host processor to see if a wireless access point is still around, Atheros’s chips check in unassisted. That saves a substantial amount of power, as it allows the phone (or other battery-powered device) to stay asleep while the Wi-Fi is awake. “The goal here, really, is to leave Wi-Fi always on,” said Tim Peters, manager of mobile communications and marketing at Atheros.
G2 Microsystems, a four-year-old asset-tracking technology company based in Campbell, Calif., that launched a low-power Wi-Fi system earlier this year, praised Atheros’s low-power chips. “We benchmark our power against them, in part because their data is in the public domain, but also because they’ve put the most effort there,” Lisa Payne, V-P of marketing for G2, said.
Ubiquitous, if not powerful
G2’s Wi-Fi chips offload even more functions than Atheros’s chips. The company’s Wi-Fi “system on a chip” (SoC) hosts the processor and networking protocols, completely eliminating the need for an external 32-bit processor. While that means G2’s products aren’t suited for high-end mobile devices like smartphones, they allow product manufacturers to bring Wi-Fi to devices that need longer battery life more than they need advanced processing power.
As Payne noted, “The minute you add Wi-Fi, people start worrying about power consumption.” G2’s products aim to bring Wi-Fi to where it’s useful without burdening devices with power-hungry processors. While G2’s WiFi-enabled products aren’t capable of handling the high throughput necessary for big data like streaming video, they do support audio and simple data transmission. “I can’t give you a perfect picture of where our technology fits,” Payne said. That’s not, however, because there isn’t a market, but because the potential applications are so numerous and diverse.
As Wi-Fi becomes increasingly ubiquitous, the market for such chips is only going to grow. Investors are taking note. ZeroG Wireless, a Cisco-backed startup working in the space, is announcing today (Monday) it that has closed a $17 million Series B round of financing from Battery Ventures, Morgenthaler Ventures and Greylock Partners. ZeroG previously raised a $13 million Series A round in June 2007. GainSpan, which was spun out of Intel in 2006 and offers SoC products with embedded Flash memory, closed a $20 million Series B round last December.
G2 showed off a WiFi-enabled remote with Philips Electronics at the Consumer Electronics Show earlier this year. Payne said that other uses for low-power, low-bandwidth Wi-Fi include applications in health care (such as WiFi-enabled scales to automatically share health data with doctors) and building management (WiFi-equipped sensors to detect temperature and initiate heating or cooling responses wirelessly). Such low-power chips could also make Internet-enabled appliances targeting energy efficiency a reality. GainSpan is particualrly interested in this market; the company announced an energy-monitoring partnership with Hitachi earlier this year.
G2’s all-in-one approach is enough to convince some consumer device manufacturers to make the switch — even when they’re not battery-dependent. Payne says one of G2’s clients is swapping out an efficient Atheros Wi-Fi chip for a G2 chip, even though its product plugs into the wall. While Payne wouldn’t disclose exactly how the chip will be used, she did reference in-home electronic displays for Internet-connected data, such as news and weather, in her description. “They didn’t need the processing power,” she said of the client.
While a “use only what you need” philosophy may not help our smartphones just yet, it’s an efficiency lesson that could come in handy for the rest of our WiFi-wired lives.
This article also appeared on BusinessWeek.com