Thursday 19 July 2012

Seamless offloading between Cellular Network and WLAN (CNW)

Last month I wrote a post about the 'Virtual Femtocell' concept. Apparently there is a company already doing this. The following is from GigaOm:

SR-Mobile, a Korean company that also has offices in Plano, Texas, is looking to help cellular carriers make seamless handoffs with Wi-Fi networks, enabling them to easily offload traffic from their cellular networks. The company, which is demonstrating its technology later this month at the Mobile Asia Expo, allows a carrier to switch a call or data traffic seamlessly between Wi-Fi, 3G and 4G. It does this with the help of a virtual radio agent mobile application on a mobile device that automatically switches between cellular and Wi-Fi modems. The VRA app works with a smart radio mobile controller that can access the network server and transfers the network traffic to the network core.

The benefit of this approach is that it allows a Wi-Fi hotspot to act as a virtual base station, which can be easily added and managed by an operator. If there’s capacity on the Wi-Fi network, it can seamlessly handle calls and data but if it gets overcrowded, it can switch back to the cellular network. SR’s approach also means that a carrier can expand their network capacity without a lot of investment, by relying on their existing Wi-Fi network or their user’s private Wi-Fi network. SR, which was founded by James Lee, a former senior staffer at Samsung Telecom America, is working on a trial with Korean operator KT, which will test SR’s technology on select LG phones.

More details about their solution in their presentation below:

1 comment:

Steve said...


The Generic Access Network (GAN) specification initially introduced in 3GPP Release 6 defines how to do this.

GAN (aka UMA) has been the technology behind T-Mobile’s Wi-Fi Calling service. Blackberry device from T-Mobile with Wi-Fi Calling support seamless in-call (and data session) handover. So handover has been commercially available in the US for years.

With the current situation at RIM, I’m not sure if the seamless handover feature is in their newest devices. It's a lot of work.

Recently T-Mobile (and others) moved away from the seamless handover requirement.

As you pointed out in an earlier post, this is similar to a femto 'app' concept, where the Wi-Fi AP gets femto characteristics.

On my VoLTE blog, I posit that support for VoLTE over Wi-Fi will reduce (replace?) the need for LTE femtos.