Speed, handoffs to boost Wi-Fi's mobile role

Wi-Fi looks set to play a growing role in mobile networks even as LTE and other new cellular technologies with higher capacity are deployed.

Several networking vendors are using this week's Mobile World Congress (MWC) as a launchpad for hardware and software designed to make carriers' Wi-Fi networks faster and easier to use. While an enhanced version of the IEEE 802.11n standard is being introduced to mobile operator gear, companies are also unveiling software for carriers to shift their subscribers from cellular to Wi-Fi networks automatically.

Cellular companies have offered their customers access to Wi-Fi hotspots in cafés, restaurants and retail stores for several years. In the U.S., for example, AT&T acquired hotspot operator Wayport in 2008 and now has about 20,000 hotspots. T-Mobile USA also has an extensive network of hotspots, and Verizon Wireless offers many as well. AT&T has recently started equipping larger areas, such as New York's Times Square, with outdoor Wi-Fi.

These networks can give subscribers a place to get faster Internet access while getting handsets off the cellular network. Femtocells, the small cellular base stations being deployed in homes and some outdoor areas, are another alternative. But with the growing numbers of smartphones and cellular-equipped tablets in consumers' hands, nearly all of which have Wi-Fi built in, Wi-Fi infrastructure is expected to become even more important.

The new carrier Wi-Fi technologies are hitting the market just as mobile operators start to upgrade their cellular networks to a new generation of equipment that offers more speed and capacity itself. Many carriers around the world have deployed or have committed to rolling out LTE (Long-Term Evolution), while some are using WiMax and others turning to HSPA+ (High-Speed Packet Access Plus), a 3G technology that can deliver a comparable boost in speed. But the demand for Wi-Fi is expected to keep growing despite these gains.

"LTE is not going to be the answer to all the mobile traffic that's out there," said analyst Daryl Schoolar of Current Analysis. "Operators are going to have to look at multiple routes to get users onto the Internet." He compared a mobile network to an interstate highway, where lanes that are added to ease congestion tend to quickly become jammed themselves. Just as a complete transportation system requires side roads and public transit, many mobile networks will require Wi-Fi, Schoolar said.

On Monday, Cisco introduced its first line of IEEE 802.11n access points for outdoor service-provider networks, the Aironet 1550 Series Outdoor Wireless Access Point series. Last week, Atheros Communications and Marvell both unveiled chips for mobile phones, being shown at MWC, that can use a form of 802.11n with two streams of packets.

Major chip makers, including Atheros, are already supplying single-stream 1x1 chips for smartphones. While 11n boosts theoretical Wi-Fi speed to as much as 150M bps (bits per second) with just one data stream, 2x2 MIMO (multiple in, multiple out), which is also available in the Cisco access-point line, takes the new technology up to 300M bps. That's only a theoretical speed, but Atheros claims its new chip will be able to achieve 170M bps in the real world.

That's far more throughput than mobile operators are offering, even on current networks using so-called 4G technologies. Verizon, for example, says average users can get between 5M bps and 12M bps on its LTE network. MIMO can also extend the range of a Wi-Fi network, allowing either bigger hotspots or fewer access points to serve the same area.

Doubling the capacity of a given hotspot with 2x2 MIMO increases the chances that, for example, a large number of people in one area could watch video on their phones via their Slingbox at home, said Farpoint Group analyst Craig Mathias. "Your ability to do what you want to, when you want to do it, goes up," Mathias said.

But the real breakthrough in getting cellular subscribers on to Wi-Fi networks wherever possible may be putting them there automatically, eliminating discovery and login processes that in some cases have been quite complicated. Cisco, Nokia Siemens Networks, Ruckus Wireless and other vendors used MWC to introduce products for seamlessly fusing cellular and Wi-Fi infrastructure.

Nokia Siemens designed its Smart WLAN Connectivity Solution to handle functions such as authentication, policy control and traffic management for both cellular and Wi-Fi networks. That can simplify management for service providers and allow subscribers to roam onto hotspots as easily as they go from one cell to the next. Cisco's new access points include the company's Next Generation Hotspot technology, which is designed for carriers to automatically log subscribers on to Wi-Fi networks and set up encrypted connections.

Ruckus Wireless introduced its Ruckus Wireless Services Gateway, which can interface with existing systems used in cellular networks for client authentication and policies. The gateway can automatically configure client devices for access to Wi-Fi networks at the time of service activation, so the users don't have to sign on every time they use services at hotspots, according to the company. Ruckus also unveiled an element management system designed to let carriers centrally manage tens of thousands of Ruckus access points and hundreds of thousands of Wi-Fi clients.

The new roaming mechanisms play into the way carriers are now deploying Wi-Fi, interspersing it with cellular coverage, said Dell'Oro Group analyst Loren Shalinsky.

"They can actually have an area of coverage that has both wireless LAN and the cellular network," Shalinsky said. In these environments, the key is to be able to steer phones smoothly to the most appropriate network at a given time and location, he said. The new tools should make that easier for carriers, Shalinsky said.

Better management of Wi-Fi networks may also enhance the operator's services and business model, he added. In the past, users who found hotspots and logged on to them were simply going out to the open Internet, even if the hotspots were carrier-supplied, Shalinsky said.

"Your service provider didn't really know what you were doing with your phone anymore," he said. Lacking that insight, they couldn't tailor services to subscribers' needs at hotspots. More information could mean, for example, better location-based services, even though new forms of targeted advertising might come along with that, Shalinsky said. "They're trying to provide a service that you want."

The biggest challenge in this kind of integrated cellular and Wi-Fi experience is implementation by the carriers, analysts said.

"They're making progress," said analyst Jack Gold of J. Gold Associates. "It's actually a hard one to do." What the carriers are striving for is being able to shift users over both without logging in and without interruption, he said.

"The switching isn't that hard, but if you've got a half-second lag in there ... people notice that, and they don't like it," Gold said.

As implementation work continues, it's clear that cellular devices will keep tapping into Wi-Fi.

"Here we are, improving the capacity and the overall performance of cellular, and yet the vendors of components and the handset manufacturers still feel that Wi-Fi is a requirement," Farpoint's Mathias said. "I think that's very telling."

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