Wi-Fi roaming: Hotspot 2.0 and Next Generation Hotspot

Wi-Fi roaming: Hotspot 2.0 and Next Generation Hotspot

Summary: New standards for automatically roaming smartphones, tablets and notebooks onto Wi-Fi networks will improve mobile connectivity — but they're still in development.

SHARE:

Even with LTE finally coming to the UK, Wi-Fi connections are still faster and more battery-efficient than most mobile broadband options — and if you're travelling, even paying for Wi-Fi is often cheaper than roaming data. But finding and connecting to the right Wi-Fi network takes too much time and is too complicated for many users. Operators faced with overloaded 3G and 4G networks would also like to use Wi-Fi offload for users as well as for backhaul data, which is why both the Wi-Fi Alliance and the Wireless Broadband Alliance are working on standards to simplify connection and roaming: Hotspot 2.0 and Next Generation Hotspot (NGH) respectively.

hotspot2-1
Several organisations are working towards making mobile broadband and Wi-Fi hotspots work together in a user-friendly manner.

Complementary standards
These are complementary standards rather than competing ones. Hotspot 2.0 is about certifying the hotspot itself, providing authentication using SIMs or certificates and the 802.11i standard, and using the recent 802.11u standard to provide performance and other information about the hotspots visible to a device. This will allow you to roam onto a hotspot with good connectivity that you have the right account to use, doing away with the need to select the network or enter your details into a web page, as you do today.

The Wi-Fi Alliance deals with the Wi-Fi hardware and the authentication specification under the name Passpoint, but this certification doesn't cover everything. The Wireless Broadband Alliance is a group of mobile and Wi-Fi operators that takes the Passpoint certification and ensures interoperability with other parts of the network — including authenticating to carriers' remote access RADIUS (Remote Authentication Dial-In User Service) servers, as well as roaming and billing.

"Next Generation Hotspot is the implementation of Hotspot 2.0 into a real, live network", explains Nigel Bird, the NGH Standardisation Manager at Orange Group.

Switching to Wi-Fi might take the strain off the mobile network and give you better coverage as part of your data plan, or you might pay in some other way. If you don't have to do any work to use the Wi-Fi at a shopping centre, for example, the hope is that you'll be happier to receive coupons or adverts in exchange for getting connected.

Wi-Fi roaming today
Some mobile operators already have proprietary Wi-Fi roaming systems. For example, Orange France's smartphone TV sports service automatically switches to Wi-Fi if users are watching a match at home.

"We want users to be able to go into a hotspot and it just works"

— Nigel Bird, Orange

Nigel Bird explains that Orange is keen to see a standard adopted because it will work with multiple handsets and access points from a range of vendors. It will also clean up a lot of inconsistencies that the testing process has found. Different carriers use different messages for connecting to their RADIUS servers, for example.

Agreeing on a standardised set of messages for all operators could have some useful side benefits, such as making it easier to setup roaming agreements, says Bird: however, the main aim, he stresses, is "to make Wi-Fi work as easily as cellular — we want users to be able to go into a hotspot and it just works".

Seamless authentication
Both Hotspot 2.0 and NGH are about seamless authentication — getting you connected to a Wi-Fi hotspot, to get online with your notebook or smartphone. They don't necessarily cover seamless handoff as you move between different hotspots. Another industry group — 3GPP, the Third Generation Partnership Project – is responsible for the seamless continuity of 3G networks and the handoff to Wi-Fi. The same techniques can be extended to cover the seamless handover of Wi-Fi sessions and there has been some work done in the current 3GPP standard, with more expected in the next one.

"The ability to continue a seamless session is not trivial," cautions Orange Group's Nigel Bird, noting that it's much easier with the IPv6 networks to which carriers are switching than with current IPv4 networks. "Its one of the things that won't really happen until this technology is more widely deployed and used. We're taking things in stages: until you get the underlying things like seamless authentication done, you can't address this. In the longer term it's an aim, but it is going to be a little while down the road before it's possible".

First, mobile operators need to support the basics — and get Wi-Fi coverage. Most operators are planning to work with hotspot providers and even free public Wi-Fi networks to get the coverage they need, according Ovum analyst Daryl Schoolar. They'll probably do it by working with both prepaid Wi-Fi services like The Cloud and wireless aggregators like Devicescape, which already has a network of 9 million hotspots (8 million in the US and expanding into Europe) and can monitor the quality of service (QoS).

"Wi-Fi has always been an incredibly fragmented world,” points out Devicescape's CEO Dave Fraser; "absolutely anyone can be a Wi-Fi operator." He predicts that carriers won't have more than a million hotpots of their own in total, so applying some measurements and QoS to the mass of free hotspots will be an important part of true Wi-Fi roaming.

Finished standards required
But most operators told Ovum's Schoolar that they wouldn't deploy Hotspot 2.0 solutions before the standards are finished — even if vendors promise that their offerings are compatible. And it's not just Wi-Fi access points and the carrier infrastructure that will need upgrading to support Hotspot 2.0 (which will involve a significant amount of time and money to achieve once the standards are agreed): notebooks and smartphones will need drivers and probably firmware upgrades too.

Devices with a SIM will need to support a new API that allows access to a subset of the SIM information.

Previously, for security reasons, there has been no communication between the Wi-Fi radio in devices and the SIM: in fact, the cryptographic key that your SIM uses to authenticate to the mobile network has never left the SIM, but now the Wi-Fi module needs to have some of the same credentials to connect you. Getting Wi-Fi-only devices to use Hotspot 2.0 may actually be easier, but devices with a SIM will need to support a new API that allows the Wi-Fi connection to access a subset of the SIM information — without compromising its security. Given the number of services that let you pay for apps, and will soon use your phone as a credit card and travel ticket, that's more important than ever.

The road to roaming
When will we see the first Hotspot 2.0 solutions? Some access points are already certified, as are some models of the Samsung Galaxy SIII, but device availability has held up trials so far and testing has had to be done with prototype handsets. Operators including BT and AT&T are involved in ongoing trials, Orange France and Smart in the Philippines have already successfully trialled Wi-Fi roaming and authentication, and another Wireless Broadband Alliance trial this year will use pre-production and shipping handsets to test the billing and RADIUS interfaces on a live network.

Devicescape's CEO Dave Fraser is concerned that there's been little effort by the GSMA to require handsets to be compatible with Hotspot 2.0, and calls the timeline "aggressive". Orange's Nigel Bird is more confident and expects that some operators will have the first commercial Hotspot 2.0 networks in 2013 — especially in areas like Hong Kong.

Unless there are delays, your smartphone could soon be regularly connecting to Wi-Fi without you having to worry about it.

Topics: Wi-Fi, Mobility, Networking, Reviews

Mary Branscombe

About Mary Branscombe

Mary Branscombe is a freelance tech journalist. Mary has been a technology writer for nearly two decades, covering everything from early versions of Windows and Office to the first smartphones, the arrival of the web and most things inbetween.

Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.

Talkback

4 comments
Log in or register to join the discussion
  • Thank you

    This is one of the most interesting and informative blogs I have read here in a long time.

    And the fan boys and shills will have little reason to post.

    Great. How can we get more?
    D.T.Long
  • Me, Too!

    I am with DT, a great article with information I really needed. Thanks for sharing. I am l working to build a wireless canopy over a Fiber network to provide cheap, high-capacity access for Mobile devices, multiplying ARPU (Average Revenue Per User) while delivering the same services already paid for. This article highlights important information and challenges ahead.
    ernieJohnston
  • Hotspot 2.0

    Does hotspot 2.0 supports
    (1)seamless roaming between APs of different vendors?
    Example Roaming from AP connected to PCCW operator to AP connected to Orange operator with the help of EAP-SIM?

    OR
    (2) Hotspot 2.0 supports seamless roaming between Cellular Network and Wi-Fi Network?

    Example: Roaming from 3G network to Wireless Network?

    Thank You
    Pramod Ganigi
    pramod.ganigi
  • ATT iPhones

    My ATT iPhone 4s will automatically authenticate onto an ATT hotspot but if I pop in a TMobile SIM card in the same phone it will not. It seems to me that SIM has to play some part in the authentication.

    Additionally some of the hangup right now going from cellular to wifi (not counting the real hand off issues) is the landing screens where we promise not download porn, pirated software, threaten the life of the President, etc. A really simple minor stop gap would be to create a universal set of conditions like this that we can agree to one time and have the equivalent of a cookie that tells the recipient network I've already agreed to the standard conditions and it just lets me on.
    stu8