As a T-Mobile UK subscriber I haven't had much exposure to Orange's UMA based 'Signal Boost' solution from Kineto, which provides the ability to make / receive calls on your mobile number via WiFi networks... so when I was offered a HTC Explorer with Signal Boost on board, I figured i'd give it a go!
So how does it work? Signal Boost uses the 3GPP UMA/GAN standard that we have seen implemented in other markets (T-Mobile in the US being a key proponent of the technology) to offload mobile traffic onto a WiFi connection.
From a user perspective, the key advantage of Signal Boost is clear - it provides the ability to maintain mobile connectivity, not just for calls but for all mobile services - MMS, SMS etc., even when the network coverage is poor. For rural subscribers for example, this is pretty awesome! A secondary benefit is that generally speaking WiFi uses less power than the mobile network, so battery life can also be improved.
It goes without saying of course that there are benefits for the operator. Aside from being able to provide a better customer experience, offloading traffic to WiFi also allows networks to help avoid capacity issues on cells particularly in metropolitan areas.
That's the theory... but how does it work? Seamlessly!
I was provided with a box-fresh HTC Explorer with an Orange SIM card. The process was simple - turn the device on, run through the setup wizard (including configuring my home WiFi network), launch the signal boost application from the launcher, enable it and a small 'house' icon appears in the notification bar. Initially it is red and when it turns greenafter 30-60 seconds, (the signal indicator also turns grey), you're connected! It is important to make sure that the WiFi connection is set to not turn off when the screen goes off.
Once set up, due to my naturally suspicious nature ;), I had a little dig around to be doubly sure that the mobile network wasn't active before making and receiving some calls as well as sending and receiving some SMS. No problems, and indistinguishable from using the device on the 'real network'.
So that's the good... what about downsides? For me there are two key issues that would ideally be fixed for the technology really to take off.
The first is handover. The current implementation by Kineto Wireless doesn't hand over calls between WiFi and the mobile network, not too useful if you happen to stray away from your home WiFi. The GSM standard does allow for this, so I imagine this will appear in a future release.
The second is device compatability. While Orange are supporting the service on the Cha Cha, Desire S, Explorer and Wildfire S from HTC, the Optimus ME and Optimus One from LG, the Orange Monte Carlo from ZTE and the Orange Barcelona and Stockholm from Huawei, it is dependent on having an Orange supplied device with an Orange approved software build. Users with devices not on the list above or with SIM free devices need not apply. Being able to just download an application from the Play Store to use Signal Boost would be excellent.
All in all, Signal Boost is a neat technology that's genuinely worth having and a viable alternative to dedicated Femtocell hardware. I'd love to see all the UK networks picking it up.