Wi-Fi offload, the process of shifting mobile data traffic from the expensive and constrained cellular network, and dropping it onto a cheaper and broadband Wi-Fi network, has benefits for both carrier and customer, including faster data, better indoor coverage, reduced expensive cellular data use and better use of limited spectrum. The first-generation solutions, which combine some databases of known public hotspots with client software to seamlessly connect to Wi-Fi, have some known weaknesses. I believe that while some problems exist with Wi-Fi offloading, those issues can be mitigated in a sensible evolution of offload technology. So here are some of the pitfalls and the ways around them:
Burning the Java - Overloading a Café Hotspot
Offloading carriers must not dump users onto a hotspot blindly, no more than baristas should pour espresso wearing a blindfold. What we need to avoid this problem is more intelligence in offload switching. If the offload technology first checks the performance of the hotspot before dropping new users onto it, then each user will have a "best performance" routing decision on which network to use, Wi-Fi or cellular.
Dead Ends and Honeypots:
Another potential problem of offloading is with Wi-Fi hotspots that are insecure or don't perform. A good offload solution needs to check the real-time performance of the hotspot and not use it when performance is below the threshold. And what about honeypots? Those feared hotspots that trick you into using them so they can steal data as they pass through? A good offload solution needs to find and eliminate these hotspots from the Wi-Fi database. Carriers must not send their users onto black hat networks--seamlessly or not.
Notspot - Unwilling Hotspot Host:
In some cases, a hotspot owner or open public Wi-Fi network operator may simply not want offload traffic put onto his or her network. This could be for any variety of reasons, but the important thing is: that's their prerogative. In such cases, the offload solution must give that hotspot operator a way of excluding their Wi-Fi from the pool of available offload hotspots. A good offload technology will provide that opt-out and will respect it for all of the devices using the technology.
Work/Life Balance - Separation of Home/Work and Public Hotspots:
There is a difference between when a carrier's offload solution helps out its subscribers by logging them into a downtown core's public Wi-Fi infrastructure, and when a carrier's offload solution logs the user into their home or office Wi-Fi networks. Mature offload solutions need to count and treat these two kinds of Wi-Fi differently. Users should be given more control, and more privacy on the private networks for which they, themselves, have provided the security keys.
Outta Control - Wi-Fi switching Against User's Wishes:
The reality is most people don't manage their Wi-Fi radio. For most, an offload client that is smart, optimizes power, throughput and metered cellular data, is a good thing. A default setting that silently re-activates Wi-Fi may seem intrusive, but cellular operators constantly make decisions about which tower to connect to, the output power of your radios, optimizing battery life, when to hand you to another tower, when to hand you from 2G to 3G to 4G or back. Wi-Fi fits in as just another tower. But regardless of the default, the offload client should allow the user to over-rule and control the Wi-Fi on/off switch.
A Full Opt-out:
So, although I think a good offload solution should be able to control the power state of the Wi-Fi radio, and should be able to activate it and seamlessly log the user into Wi-Fi hotspots in a way that benefits both user and carrier, I still understand there are users who will not want this loss of control. Whether they have a corporate policy against public Wi-Fi, concerns about safety of 2.4GHz spectrum, or can manage better battery life by controlling Wi-Fi themselves, it doesn't matter. The user should be able to fully opt-out of Wi-Fi offload. Carriers' offload solutions should respect the subscriber's right to choose.
Demand for mobile access to data is growing with no signs of abating. The industry needs to respond. Only by applying many different mitigation techniques together can we satiate the consumers' appetite for anytime, anywhere access. Wi-Fi offload is one of the easiest, cheapest and most obvious solutions, and will be part of the cellular landscape for many years.
Derek Kerton runs the strategy practice for the Kerton Group, a consulting firm focused on wireless telecom, is chairman of The Telecom Council association for global telecom executives, and published his first mobile app in 1999. Details at www.kertongroup.com.
Disclaimer: Derek Kerton is an advisor to Devicescape. This column was written in response to an Editor's Note by FierceBroadbandWireless editor Tammy Parker about the pitfalls of Wi-Fi offloading.