About GSM/Wifi handover

Alan Jones junk at alan2.com
Tue Jul 17 15:30:46 CEST 2007

> Do you think we have enough information about the GSM modem embedded in this
phone to allow this service to be implemented?

While I cannot answer for certain, I would say that it is incredibly unlikely that we will get anything other than an
analog voice signal from the phone, so we would have to re-run it through a gsm vocoder to get the data you want, which
isn't going to produce great quality voice. Some higher bit rate VoIP codec might work better.

With that said, I think the much bigger issue here is getting cooperation from the networks. You can't even think about
orchestrating a handover without the provider explicitly allowing you to talk to their network. Again, I cannot say for
certain, but I would bet that it is not something they just give anybody who asks access to. The T-Mobile setup that was
recently released is controlled by T-Mobile on both ends, and I would bet it is enabled on a per-subscriber basis, after
you pay for it. I hope there is a trend in this direction to open the cellular network (and so does the FCC), but I
wouldn't hold my breath right now.


(apologies for the fake reply, this was sent before I subscribed.)

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