My Mobile Phone, Wi-Fi Use and Offloading

When I still had a prepaid SIM in my mobile phone and had to pay for mobile data use by the megabyte I was quite heavily using my phones Wi-Fi at home so my e-mail, web browsing, podcast downloads, etc. would run over my “free” network while being at home. Great money saver. These days, I’ve switched to a contract that includes 1GB of data a month. It’s interesting to notice that, probably unsurprisingly, I only use Wi-Fi for exceptional things like download a couple of hundred megabytes of podcasts every now and then. The rest is all 2G/3G now.

I guess it has to do with convenience as it is still a bit of a hassle to switch applications from 3G to Wi-Fi at home. Symbian makes it quite easy by having connection profiles and priorities so applications always connect to the network with the highest priority. However, the application doesn’t change the bearer once it is connected so a manual restart of applications is still required with this scheme. If you pay by the megabyte, there is an incentive to do that, but if you have a huge bucket of data available at least I’ve stopped caring.

So why do I post about it? Well, I’m thinking ahead a bit and about Wi-Fi offload scenarios. I can see network operator Wi-Fi hotspot networks and Wi-Fi networks at home as interesting offload infrastructure that is already available today. But to make it work, the switchover has to be fully automatic and fully seamless. On the usability layer that means that the phone automatically switches the bearer without the applications knowing it. On the protocol layer it means that the IP address assigned to the device must not change so the switch is transparent to the application. In other words, a form of mobile-IP is required. And there is more than one option to choose from.

When home Wi-Fi networks are part of the equation, things have to get a bit more intelligent still, as a mobile device should then also be able to access devices in the home network. Once could do that with an additional local IP address that comes and goes when the home Wi-Fi is in range or a tunnel back to the home network. This would have the additional benefit that the user could access devices and data at home even while he is not under the umbrella of his own home Wi-Fi.

I think this should be standardized to bring together manufacturers and network operators. If every operator comes up with its own solutions and manufacturers to the same thing it’ll be ugly. And since connectivity is the bread and butter service of network operators, it’s them who should take this up and get it working. In the end it has two benefits for them, macro network offload and integrating services running in the home network.

Finally, it has become more apparent than ever now that this is also a good opportunity to make sure that communication over public Wi-Fi hotspots is secure, no matter whether a notebook or mobile device is used. For details see my recent post on FireSheep. And don’t think you are secure just because you access that popular social network side from a mobile phone with an app instead of via the browser on the notebook. Are you sure the app encrypts the data before it is sent?