Ericsson has unveiled a Wi-Fi access point and controller for offloading cellular traffic in densely populated areas such as stadiums. Its goal is to allow users to switch seamlessly from the cellular network to a local Wi-Fi network to solve network congestion problems.

The company sees it as a way to give thousands of spectators the bandwidth needed to update their Twitter and Facebook statuses on their phones while they all watch the same game or concert. It could also allow sports fans to see instant action replays on their phones from their stadium seats, or for music fans to upload photos and videos of a concert as it happens.

Stadiums are so densely packed that networks easily get congested, said Sheila Burpee Duncan, Ericsonn's head of Wi-Fi marketing, at the Broadband World Forum in Amsterdam on Tuesday. That's a problem for customers, who are frustrated by the poor service, and for operators, who miss out on potential revenue.

To mitigate those network problems Ericsson has launched the WIC 8000 Wi-Fi controller and the AP 5114 Wi-Fi access point. Combined, they create a local Wi-Fi network that integrates with the mobile network and is optimized for use in stadiums, shopping malls and other densely populated areas, Ericsson said.

The access points can be positioned very close to one another to increase available bandwidth for each user. That poses a problem, though: There are only four non-overlapping 2.4GHz Wi-Fi channels, so access points that are close to each other tend to interfere.

"The interference is a challenge and that is why we use interference mitigation techniques in the software," she said.

As spectators come into the stadium, their data traffic can automatically be switched from their cellular provider to the Wi-Fi network, said Burpee Duncan. "There are a number of different ways you can do it," she said. At the Broadband World Forum Ericsson demonstrated the use of ANDSF (Access Network Discovery and Selection Function), a feature of 3G networks, to invoke an automatic connection to a network, but it could also have used MAC Authentication or Hotspot 2.0, according to Burpee Duncan.

Ericsson's handover technique works with Wi-Fi enabled phones and tablets including the latest iPhones and Samsung smartphones.

Each of the Wi-Fi access points can generate up to 16 different SSIDs, allowing the creation of up to 16 virtual access point networks. "That enables multiple mobile operators on the same Wi-Fi network, but with a connection to their own back office," she said.

Operators in turn can use those connections for roaming and wholesale agreements as well as hosted models, she said.

When a phone hands over to a Wi-Fi access point, Ericsson's controller connects it to the appropriate carrier's core network. There, the operator can choose to deduct data usage on the Wi-Fi network from the subscriber's data plan, or to offer the Wi-Fi service for free, said Burpee Duncan. "That really depends on the subscription."

The controller can handle up to 2,000 access points. "A couple of hundred access points is generally a minimum for a 20,000 seat stadium," she said. Ericsson's network management system can handle up to 100,000 access points in a single instance.

While each access point can in theory handle up to 600Mbps, the stadium "has to have the backhaul network to support it, so the actual bandwidth capability may vary," she said.

The stadium Wi-Fi technology represents Ericsson's first Wi-Fi product launch since it acquired Wi-Fi specialist BelAir Networks in April this year.