The Wi-Fi Alliance has announced an attack on one of the main problems with wireless LAN phones, by certifying features to extend battery life.

The industry group that certifies interoperability of Wi-Fi products is adding a label it calls WMM (Wireless Multimedia) Power Save, which identifies products that have reduced the power needed to use multimedia applications over wireless LANs, says Frank Hanzlik, managing director of the alliance.

Using a wireless LAN for VOIP (voice over Internet Protocol), streaming video and other multimedia applications increases the power consumption of Wi-Fi, which already tends to drain battery power because of ongoing searches for nearby access points, according to IDC analyst Abner Germanow. The size and weight requirements of Wi-Fi phones as well as dual-mode cellular and WLAN handsets, plus the need to carry them around all day, make power consumption even more critical.

"The gating factor on a lot of the different types of functionality has come down to power," Germanow says.

Equipment certified for WMM Power Save should extend battery life under multimedia use by between 15 percent and 40 percent. The Wi-Fi Alliance has also published a White Paper on the subject, and a list of products that have received the seal.

So far these products have been given a seal:

  • Atheros AR5002AP-2X access point
  • Broadcom AirForce BCM94704AGR dual-band 802.11a/g access point
  • Broadcom AirForce BCM94309CB dual-band 802.11a/g PC card
  • Cisco AIR-AP1231G-A-K9 with AIR-RM21A-A-K9
  • Conexant 802.11a/g Prism WorldRadio
  • Marvell Semiconductor 802.11a/b/g WLAN router
  • Ralink 802.11a/g Mini PCI
  • Winbond Mini PCI 802.11a/b/g WLAN Client

A variety of chipsets, product reference designs and devices from vendors including Atheros, Broadcom and Cisco. have been certified in the first round. There won't be a WMM Power Save logo on the boxes of certified products, Hanzlik said. Instead, information about each product's certifications will be available on the Wi-Fi Alliance's Web page.

Better signalling
WMM Power Save includes improved signaling capabilities and mechanisms for fine-tuning power consumption. It uses some elements of the IEEE 802.11e specification, a standard for improving multimedia on Wi-Fi that was approved in September, Hanzlik says.

Most of the rest of 802.11e will be included in the WMM Scheduled Access certification, which will be introduced in mid-2006, Hanzlik said. The original WMM certification, introduced last year, covers technology that can prioritise certain types of packets over others in a queue. WMM Scheduled Access will expand on that by essentially providing multiple queues so multimedia packets can travel more smoothly through the network, he said.

The need for longer battery life in Wi-Fi devices spans both consumer and enterprise users, Hanzlik says, especially for handsets. "There's a very strong level of interest ... in trying to optimise the user experience there," Hanzlik said.

There are two basic types of devices for voice over Wi-Fi, according to IDC's Germanow: Wi-Fi-only phones for roaming around an office, which are essentially cordless phones, and dual-mode cellular/Wi-Fi phones that workers or consumers can use at home, at work or on the road. Sales of mobile phones equipped with Wi-Fi (not necessarily all will use voice over Wi-Fi) will top 100 million per year by 2009, according to a 2004 IDC report.