Mobile data traffic is growing…and fast. A new approach aims to seamlessly offload data from carrier networks to Wi-Fi in response to the demand for more bandwidth.
Wireless data use is growing by leaps and bounds. The Cisco Visual Networking Index
(Global Mobile Data Traffic Forecast Update 2011-2016) forecasts that
worldwide mobile data traffic in 2015 will be 26 times greater than it
was in 2010. And while there is considerable controversy about the
details of estimates, there's no question that demand is growing much
faster than carriers' available bandwidth, even with considerable
improvement in efficient use of the airwaves.
One solution is moving a good chunk of the data that currently moves
over carrier networks onto Wi-Fi. Today that is much easier said than
done. But a new approach called Hotspot 2.0 should make seamless
transitions between cell-type networks and Wi-Fi a reality.
Wi-Fi offload already works well when you are in familiar surroundings.
Today's smartphones and tablets are designed to use Wi-Fi when it is
available. When a device detects a network on which it is already
registered—say your home or office—it automatically connects. Public
networks don't work so well, unless they are completely open—and then
you face the problems that you don't really know
what is on the other
end of that network and that all wireless traffic is completely
unencrypted.
Hotspot 2.0 (called Passpoint by the Wi-Fi Association and IEE Standard
802.11u by engineers) is designed to make this transition from
cell-type networks to Wi-Fi completely seamless. Its big advantage to
carriers is that it will lighten the load on their increasingly
overburdened networks while allowing them to control access to private
or shared Wi-Fi networks. For users, it means faster and more reliable
networks, especially where demand for service is very high.
One thing that has made switching from carrier networks to Wi-Fi
difficult is that typically some sort of login process is required. If
the network is secured by Wi-Fi Protected Access, the user needs to
know the passphrase. This presents the carrier with the huge problem of
distributing passphrases and still makes it all but impossible to
restrict access to paying customers. (Wi-Fi is much cheaper to deploy
than cell-type networks, but there still is significant cost involved,
especially the expense of the "backhaul"—connecting access points to the
internet backbone.)
The alternative leaves the access point open, but uses authentication,
typically a username and password, to a server to gain access to the
internet. This controls access well, but requires a manual login, making
the process anything but seamless.
Hotspot 2.0 (see illustration) automates the process. Instead of the
user logging in, the phone or other mobile device can identify itself to
the network, most often by using the same Subscriber Identity Module
(SIM) card used for authentication on the carrier network. The Wi-Fi
network checks with the carrier to make sure the device is authorized
before letting it connect to the internet. The process is quick and
invisible. (If you care to know about it in a lot more detail, check out
this Cisco white paper.
Niels Jonker, chief technology officer for Boingo,
a leading operator and aggregator of Wi-Fi networks, says he expects to
see Hotspot 2.0 networks start to appear early in 2013. The first
installations are likely to be in sports stadiums, where the tightly
packed mass of device users often overwhelms the network, especially
when everyone tries to send a photo at the same time. Although the
wireless capacity assigned to Wi-Fi is quite small, it is possible to
restrict access point coverage to a small area, which allows the same
channels to be used over and over. You can also expect to see Hotspot
2.0 installations show up in densely populated urban settings, such as
the Times Square area of New York.
Hotspot 2.0 won't solve all the problems of today's wireless networks.
Wi-Fi is not designed for rapid handoff between access points, so it's
not going to work well in moving vehicles. It's not likely to do much to
fill-in coverage dead spots either. But it could go a long way toward
solving a growing capacity crunch.