Wi-Fi is everywhere these days. With an estimated 200 million access points deployed in homes, offices and public locations worldwide, Wi-Fi is the in-building wireless technology of choice.

Furthermore, research house IHS iSuppli projects 1.2 billion WLAN units will ship in 2011. Smartphones will be the home for a staggering 42.7 percent of those WLAN units. So it becomes natural for mobile-service providers to look to Wi-Fi as an extension of the mobile network.

Steve ShawThe State of the Networks
To date, mobile providers have let subscribers use Wi-Fi to offload web services like YouTube directly to the Internet. It's a "hands-off" approach, leaving users to struggle with figuring out the different attachment procedures and hunting down Wi-Fi access points.

What's the incentive to go through these headaches? A recent survey of smartphone users found that a number of them (37 percent) primarily used Wi-Fi because it was "faster than the macro cellular network." If operators provide a poor network experience, subscribers will turn to alternatives — not exactly a recipe for success or a positive user experience.

This negativity dilutes what are arguably the biggest triumphs of the mobile industry — the simplicity, security and seamlessness of the user experience. Subscribers pop a SIM card into a phone, which automatically establishes a secure connection to the network core, authenticates and authorizes the device and provides a consistent user experience around the world.

Can Wi-Fi deliver a mobile experience? Yes.
Wi-Fi networks tend to have a mish-mash of security approaches. Access points in homes use a key, while in the office, they may have a centralized subscriber management system. Public locations are often wide open with no link layer security.

There is a tremendous amount of industry work to develop an easy approach to accessing Wi-Fi, particularly in public locations. The major standards bodies have jumped into the fray with HotSpot 2.0, ANDSF, WiSPr and other proposals.

Central to these proposals is the ability to leverage existing SIM credentials to attach and authenticate against public Wi-Fi access points. There is nothing more for the user or the network service provider to remember. It simplifies access, authentication and authorization of the device. In fact, it may be possible to extend SIM authentication to home Wi-Fi in cases where subscribers take their mobile and broadband services from the same provider.

Meanwhile data security, particularly in open public Wi-Fi locations, has become a concern. For example, a new plug-in available for the Firefox browser called Firesheep makes it quite easy to hack network session identification and authentication codes for popular websites like Amazon, Google, Facebook, Twitter and more.

If a Wi-Fi access point is identified with a specific mobile service provider, the problem is magnified. Subscribers expect a level of security when using mobile services, and yet operator-branded public Wi-Fi access points commonly don't have any link layer security.

Wi-Fi has opened a new connection on mobile devices — one that connects directly to the wild, wild west of the public Internet.

Ideally, public Wi-Fi sessions between smartphones and the network would be secured as a benefit provided by the mobile providers to their subscribers. People expect their smartphones to behave in a common and consistent manner, regardless of the underlying network connection.

For mobile service providers to maximize the benefit of Wi-Fi and actually turn Wi-Fi into a true extension of the mobile network, there needs to be a mechanism for establishing a secure connection to the core network. This is the 3GPP's existing Generic Access Network (GAN) specification. The standard was developed explicitly to allow mobile providers to use IP and internet as a Generic Access Network.

A Smarter Wi-Fi Solution
With a GAN application on a smartphone, Wi-Fi can become a seamless extension of the mobile network. GAN relies on SIM-based authentication for establishing a secure connection over IP, addressing both the access/authentication, as well as the security holes inherent in today's public Wi-Fi.

In addition, users can access all circuit, packet and web services over Wi-Fi in the exact same manner as the macro cellular network. There is no difference in user experience between the two networks.

Wi-Fi for Coverage and Capacity
However, the real benefit of enrolling Wi-Fi into the macro network framework comes in the form of capacity and coverage.

Using Wi-Fi this way, mobile operators are able to tap into the massive spectral capacity offered by Wi-Fi. Beyond the spectrum, Wi-Fi comes with its own dedicated, high-speed IP backhaul facility. For mobile providers, Wi-Fi is a ready-made, high-performance, low-cost IP access network.

As for in-building coverage, it may always be a challenge for mobile providers. Yet Wi-Fi is already installed in the places where subscribers need a coverage boost the most — the home and office. Turning Wi-Fi access points into mini-cell towers improves customer satisfaction by improving coverage along with reducing churn.

Wi-Fi is the predominant in-building wireless technology. With 3GPP's GAN specification, mobile operators can immediately enlist any and all Wi-Fi access points around the world to be mini-cell towers, delivering mobile services, boosting coverage and offloading the macro network.

Steve Shaw is vice president, corporate marketing, at Kineto Wireless.