Passing the Baton

The convenience of so-called “seamless” roaming and hand-offs between VoWi-Fi and mobile networks is attractive and useful today for both business and consumers. This has stimulated new technology and actual trials by service providers. These efforts already are proving out the technology and very well could lead to deployments, particularly for business users, in 2006.

An ongoing trial of seamless hand-offs between Wi-Fi and mobile networks, coordinated by BellSouth Corp., tests the use of dual-mode Wi-Fi/mobile handsets in a corporate setting at Grey Advertising in Atlanta, a division of Grey Global Group Inc. The trial involves the Avaya Inc. IP PBX, Motorola Inc. products for Wi-Fi and hand-offs (with Proxim Wireless Corp.), and the Cingular mobile network (owned by BellSouth and AT&T Inc.).

The trial started in August using about 25 Motorola 620 dual-mode phones, which were given to Grey sales executives and other staff that used mobile heavily. The dual-mode phones by Motorola were designed to work with the BellSouth Cingular mobile network.

“The key takeaway is that we have proven the technology works,” says Mario Muth, senior product manager of enterprise wireless services at BellSouth. Challenges included new patterns of Wi-Fi coverage. While Wi-Fi for data is used primarily at desks in offices, VoWi-Fi can be used anywhere in the building, including parking garages, stairwells and break rooms, which meant Wi-Fi coverage had to be beefed up at Grey’s offices.

Motorola’s dual-mode phone

Also, while the number of phones in use does not stress the Wi-Fi network, the trial uses 802.11a transmission so channels do not overlap. “You need dedicated bandwidth and quality of service for voice,” says Muth.

BellSouth is “still doing readouts on the impact on minutes of use,” says Muth, so the company still is deciding on when and how to do an actual deployment, “but we are working with Avaya on this, so we are looking at 2006,” he adds.

Avaya and Motorola also are involved in a trial of hand-offs between mobile and Wi-Fi with Chicago-based food distributor Anthony Marano Co. With huge warehouses full of perishable products that have to move in and out fast, and Burger King as one of its major customers, Anthony Marano sales executives have to be available to customers no matter where they are.

Making sure hand-offs between networks went well was one of the key goals of the trials. “Surprisingly, that is one of the things that works reliably in the system,” says Chris Nowak, IT director at Anthony Marano. “It is coordinated by a piece of Motorola hardware, which determines the quality of the Wi-Fi and cell coverage, and institutes PBX functions to bridge the call back into the phone. You may hear a click or may not, and you can walk outside of the facility and maintain a call.”

With a facility that spans 300,000 square feet, the technology helped reduce costs in a company that had been using mobile heavily.

While on the Wi-Fi network, users have access to all PBX functions. “That is why we found it such a compelling product,” says Nowak.

With Marano staff reluctant to give up their phones at the end of the trial, the company is hoping Motorola can stick to its goal of pricing the devices similarly to a high-end desk phone.

Getting a range of devices is the main challenge at this point, says Tom Kershaw, vice president of communication services at VeriSign Inc., which has been conducting an extensive trial of hand-offs with several universities, including The University of Michigan.

“There are about five devices that we can use,” says Kershaw. Although network equipment is important, he says, “the devices, oftentimes, are the gating factor.”

It is the handsets, says Kershaw, that initiate much of the negotiation for the hand-offs. One of the challenges is that the rules for what is a strong or weak signal are vastly different in mobile and Wi-Fi networks. In a mobile network, anything less that 65 percent signal strength (about two bars on the typical signal meter) will greatly impact quality, but 10 percent strength may be flawless in a Wi-Fi network. “It adds a layer of complexity to handset logic,” says Kershaw, “and the decision point of when to go for another network is coded into the handsets.”

Despite the current limitations in handsets, viable handsets are coming into the market from manufacturers in the Far East, for example, says Kershaw. “I think we will get into sub $200 to $300. That is what the market is waiting for.”

The other issue is the stability of handsets. “Any brand new handset is going to have issues. Now we are starting to see the second and third rounds coming to market, so 2006 we think will be the year that handsets are available in bulk,” Kershaw says.

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