Peter Judge at TechWorld reports that BT may be introducing a combined Wi-Fi/cellular service, but it's not what you think: When customers make calls in their homes using a combined GSM/Wi-Fi phone, the call is carried over Wi-Fi between the phone and the access point. But the access point is backhauled over the GSM network. Instead of realizing the cost savings of carrying a call over IP over a broadband fixed connection, BT chooses to use the more expensive GSM network. The service becomes, in essence, a method for improving cell phone coverage in the home.
The idea doesn't make sense in any context, but you might understand it if the offering was being made by a cell phone operator that stands to benefit by keeping calls on its network. But this is BT, which doesn't have a cell phone network and will supply the cellular link via resale agreements with a mobile operator. It would make so much more sense for BT to backhaul the access points using its own wired network, using voice over IP and charging customers slightly reduced rates than the cell phone networks for the calls that use the system. That sounds like it could be a profitable service and would allow BT to beat out cellular operators that don't own their own landline networks.
This service is basically an update to the previously announced Bluephone initiative and shouldn't be available until 2006. Given the track record of the Bluephone plan, which was initially set to be introduced using Bluetooth instead of Wi-Fi in 2003, it might not be surprising if the whole plan changes again.
This does seem a little puzzling, but look at it this way. Between the phone and Wi-Fi access point, the call is still carried as VoIP traffic. This means that the handsets used for this would be the same ones used for dual-mode services where the VoIP traffic is carried over a broadband line. By doing this, BT could start purchasing handsets from handset manufacturers and handset manufacturers can fine tune their products. Consumers with poor coverage in the home can start seeing the benefits of this. All this, while BT buys time to get the real solution ready. When BT is ready, there will be better phones and possibly more choices available than if BT were not to take this interim step. This must be an interim step considering BT's involvement in the FMCA and UMA consortiums.
It may make sense depending on the MVNO model. An MVNO doesn’t have a Radio Access Network, but it can have its own MSC and HLR. In that case, calls carried using Wi-Fi will remain on BT network.
And even in the case that BT has no MSC, the MNO access charges using BT Bluephone should be much cheaper than using a GSM base station from the carrier.
Also you have to consider that VoIP service is not free. May be BT is planning to have plans that are more competitive than paying two services for a cell phone and VoIP.