Sprint has been named as the carrier that's working with Boingo on a multi-year WiFi offload agreement to automatically connect its customers' handsets to WiFi when they visit 35 of the major US airports.

Boingo Wireless Inc. revealed in March that it had signed an offload deal with a Tier 1 US operator, and Sprint Corp. (NYSE: S) confirmed the relationship on Thursday, noting that it would include deployment on up to 40 million of its handsets for WiFi offload. (See Boingo Provides WiFi Offload for US Tier 1.)

The pair have been in market trials with "millions of handsets" since then and plan to expand to 35 airports this year. Those customers with the Boingo app downloaded on their device will automatically be authenticated on WiFi when they enter one of the airports.

Boingo CTO Dr. Derek Peterson told Light Reading in March that the deal with Sprint also encompasses all the mobile virtual network operators (MVNO) on Sprint's network, which is good news for some of the WiFi-first MVNOs like Republic Wireless , Scratch Wireless and ostensibly even Google (Nasdaq: GOOG)'s Fi service, because they can now access more public access hotspots. (See Google's WiFi-First Mobile Service 'Fi' Is Here.)

Want to know more about carrier WiFi strategies? This will be just one of the many topics covered at Light Reading's second Big Telecom Event on June 9-10 in Chicago. Get yourself registered today or get left behind!

Boingo's deal with Sprint also includes support for Passpoint, which is what takes it from WiFi roaming to offload. Peterson explained that many carriers already have WiFi roaming deals in place in which they choose when or where to roam. That is the nature of Boingo's relationship with AT&T Inc. (NYSE: T), for example. (See Boingo: Carrier WiFi Offload Still a Year Out.)

Passpoint, or Hotspot 2.0, changes the equation to automatically connect users to WiFi as it would to any cellular network with WPA2 enterprise-grade encryption. It takes no intervention on the part of the customer, but the data consumed over WiFi do not count against their cellular plan. (See Passpoint Moves Towards Carrier WiFi.)

Peterson said there have been challenges in getting Passpoint implemented, including designing the technology to connect to only high-quality access points that the carrier has a relationship with and determining who owns the user experience design on the device -- the carrier or the handset maker.

"We're still working through it as an industry of how do you handle subscriber management type of decisions on the device," Peterson said in March. "[For example], if you're on one of the prepaid MVNO phones and you run out of WiFi minutes or megabytes, how does your device show it back to you that you're out and can add more?"

Peterson said that the Wi-Fi Alliance and Wireless Broadband Alliance are working through these issues together and the carriers will ultimately be able to steer their customers' usage pretty well with all the network data they have on policies and quality of service. He expects WiFi offload to become a lot more common this year as operators offer WiFi calling and focus on relieving congestion on their networks. (See Sprint Extends WiFi Calling to the iPhone and Carrier-Grade WiFi Still 2 Years Away – CableLabs.)

— Sarah Thomas, , Editorial Operations Director, Light Reading