The Predictability of Voice
March 15, 2004
Switch vendor Meru says its technology, when used by Wi-Fi handset makers, can give voice over WLAN phones the same or better talk time as cell phones.
When Meru Networks launched last year, it made a lot of noise about how it would support voice over wireless LAN (VoWLAN) like no other. Now it's attempting to put its money where its announcements are.
The company said today that it is licensing drivers for use by Wi-Fi handset manufacturers that, when used in conjunction with Meru equipment, will provide as much as 300 percent more talk time. Wi-Fi chips are notorious power hogs and handsets that use them are not known for getting the same kind of talk time or even standby time as a typical cellular phone.
"Cell phones, they can have three to five hours of talk time," says Joel Vincent, senior product marketing manager for Meru. "It's not that it doesn't use a lot of power, since it is transmitting sometimes a mile away. The transmission is just so predictable."
Predictability is the key, for it allows the phone to shut down some services and only bring them up at regular intervals when need. Voice over Wi-Fi doesn't usually have that; the phone is on constantly, because with Internet Protocol transmissions, the phone can't be sure when it will receive a packet on the network.
Meru's driver will tie into the handset directly, allowing it to synchronize efficiently with the Meru access points (APs) on the network."The phone knows exactly when it's going to get its packets," says Vincent.
Phones using the Meru firmware will be able to tell when they're hooked up to Meru infrastructure products. Otherwise, they'll function exactly the same as normal -- turned on 100 percent of the time. Likewise, phones without the firmware will function normally with Meru's equipment.
Currently only one handset vendor is signed on to use the firmware: Hitachi-Cable of Japan. How much extra talk time a handset can get depends on many factors says Vincent, but he says it could go as high as 300 percent.
Vincent says that the ability to handle this predictability in synching handsets and equipment is something other switch vendors can't duplicate, as Meru built the technology directly into its proprietary MAC chip.
"If you ran a cell phone network like Wi-Fi, everyone's phone would decide when to transmit and where, and it would be utter chaos," says Vincent. "The cell phone world wouldn't exist. Clients can't be going on a free-for-all and accessing any channel they want. You have to make the channel access predictable."
Several Wi-Fi chip companies, including Agere and Texas Instruments, are at work making silicon for 802.11-based handsets that they hope will also improve power usage and thus overall talk time.
Meru, like many WLAN switch vendors of late, is quickly adding new features and services to differentiate itself, as well as take care of security that was lacking in the original product. Last week the company updated its product to include WLAN Radar and a rogue AP intrusion detection system (IDS), and is working with Cavium Networks to make an SSL