Voice over Wi-Fi set to hit stride

Voice over IP over Wi-Fi, or VoFi, is a technology that’s both old and new. Equipment vendors such as Cisco Systems, Motorola, SpectraLink and Symbol Technologies have been supplying VoFi solutions in some form or another to the enterprise sector for several years. Today, in-building VoFi systems combined with outside cellular telephone service are at the cutting edge of the wireless evolution.

But for wireless equipment vendors and integrators, VoFi and dual-mode cellular/VoFi are big question marks. Should they dive into this space now, while the technology is still in the early adopter phase or should they hang back and let others suffer at the bleeding edge until VoFi matures and sales volumes increase?

In simplest terms, VoFi systems convert voice signals to IP-compatible digital packets and then transmit those packets over an 802.11 network. Once the packet conversion has been executed, they can be transmitted over a wireless local area network as easily as any piece of data.

That’s the theory. However, the practice is somewhat more difficult, according to Ben Guderian, SpectraLink’s vice president of market strategy. “The reason is that Wi-Fi is a shared bandwidth Ethernet pipe,” he said. “As more users access the network, delays can occur, which can result in interrupted voice calls.”

Wi-Fi coverage also is an extremely big issue, said Stephen Stark, president of US Info-Comm, a telecom solutions provider and SpectraLink dealer in Deerfield Beach, Fla. “When you’re walking around, you don’t want your conversations to drop out due to coverage gaps,” Stark said. “Data can afford lapses, but voice is not forgiving at all.”

To cope with this problem, the Wi-Fi infrastructure must be able to differentiate between voice and data packets and give priority to the former, said Ben Gibson, Cisco’s director of mobility systems marketing. “This ensures that voice calls won’t be interrupted,” he said.

Ensuring that the handoff of VoFi calls between enterprise access points occurs smoothly and seamlessly is challenging enough. However, switching such calls to an external cellular telephone network when a dual-mode user exits the building adds a layer of complexity that increases the challenge exponentially.

The big problem is that wireless carriers aren’t working together as well as needed to make dual-mode operations function well, Stark said.

One reason is money. Currently, wireless carriers haven’t been able to figure out “how to make money by adding Wi-Fi to their coverage,” Guderian said.

But the challenges associated with delivering VoFi calls haven’t slowed product development. For example, Cisco has offered VoFi products for the past four years, with the Unified Wireless IP 7920 portable handset central to its offering. Designed to resemble a cellular phone, the IP 7920 supports a full range of business wireline features, including Caller ID and Call Forward. Its signals are carried using 802.11b technology at data speeds of ranging from 1 Mb/s to 11 Mb/s.

Symbol first entered the VoFi market in 1997 with the introduction of the NetVision voice-over-Wi-Fi phone, according to Chris McGugan, senior director of marketing for Symbol. Today, VoFi is a standard feature on all Symbol mobile computers. For instance, Symbol’s MC70 offers VoFi, and integrates it with a wireless PDA, computer, scanner and imager in a hand-held package.

SpectraLink’s NetLink wireless telephones are established VoFi stalwarts at hospitals, big box retailers and hotels. Today, the company is aiming upgraded versions at the general enterprise market. In particular, “We are meeting the need for mobile employees to have ongoing access to their corporate PBX,” Guderian said.

At Motorola, efforts continue in refining its GSM/VoFi CN620 handset. “We have been trialing the CN620 for the past year, and it has proved itself in seamlessly handing off between Wi-Fi and GSM,” said Kevin Goulet, Motorola’s director of enterprise mobile office product development. “It comes with a number of special keys to support Call Transfer and Call Forwarding so that the CN620 provides the PBX functionality that enterprise users expect. We’ve been testing it with mid- to full-sized B2B enterprise customers and plan to bring it to market next year.”

Although VoFi vendors say the market still is in the early-adopter phase, there are signs that the technology is positioned for a wide-scale breakout in the near future.

One driver is the “really sharp increase” in the quantity and diversity of Wi-Fi-enabled clients, according to Cisco’s Gibson. “We are also seeing many of the major handset manufacturers starting to produce both single (Wi-Fi) and dual-mode handsets — and the costs of the handsets are starting to fall,” he said.

Another driver is the availability of smaller, more integrated and affordable VoFi technology, such as Atheros Communications’ AR6101 wireless IP platform. These single-chip VoFi solutions can be installed directly into handsets to radically reduce the per-unit manufacturing cost, according to Todd Antes, Atheros’ vice president of marketing.

“Today, voice-over-Wi-Fi handsets sell in the $200 to $500 price point,” Antes said. “With the AR6101, this will reduce the cost to $100 or less. That’s the point where these handsets will make more sense to people.”

A third — and perhaps the most important — driver is money. “Just as there’s a business case for putting voice on a company’s IP network, there’s also a case for adding mobility to the equation,” Gibson said. “It’s a real opportunity for large organizations to save on telecom costs on large campuses, where there’s a need for a lot of mobile voice traffic.”

For land mobile radio dealers, VoFi offers a solid opportunity for them to differentiate themselves from the rest of the market, according to SpectraLink’s Guderian. “You can sell this technology to help provide mobility to your clients, while reducing their total costs of ownership,” he said.

Better still, VoFi expands the Wi-Fi business case far beyond its original limits, offering dealers and systems integrators vastly increased sales opportunities. “Wi-Fi is not just about deploying access points anymore,” Gibson said. “It now encompasses a wide range of equipment and services. This means dealers can now offer integration services to their clients and add mobility when deploying Wi-Fi.”

Editor’s note: For details on the newest technologies designed to solve the cost, transmission and coverage problems associated with VoFi, see Senior Writer Donny Jackson’s cover story on page 44.