"airplane mode means no transmission. The phone can still receive and might be remotely activated by a so-called silent text."
I don't think that's workable.
Remember, the phone is not a walkie-talkie - it's a node on a cellular network and has to participate on that network to be addressable and receive messages.
This means it is answering status requests, sending ACKs, etc. In order to receive a text, the phone has to be sending TX outward.
Is it possible that there could be a phone network built to send RX only transmissions to network nodes (handsets) that were otherwise silent ? Sure - but I don't believe any of the GSM/3G/LTE specs define any such behavior.
In short, if your phone is truly in an RX mode, I don't think it can receive a SMS - or participate on the cellular network in any way.
Back when I worked with LTE (now 4G) there was no such thing in the S1AP protocol at least.
Me, and a colleague, where actually the first to get a paging through from network to a UE in LTE. Sure, it was a test UE the size of a small refrigerator, and the network was a simulated network. But still. All layers involved.
The paging, at the time, was the only way for the network to silently contact the UE, and that message didn’t contain any information. It was basically just a: “Hello IMEI X, are you here?”
I don't think that's workable.
Remember, the phone is not a walkie-talkie - it's a node on a cellular network and has to participate on that network to be addressable and receive messages.
This means it is answering status requests, sending ACKs, etc. In order to receive a text, the phone has to be sending TX outward.
Is it possible that there could be a phone network built to send RX only transmissions to network nodes (handsets) that were otherwise silent ? Sure - but I don't believe any of the GSM/3G/LTE specs define any such behavior.
In short, if your phone is truly in an RX mode, I don't think it can receive a SMS - or participate on the cellular network in any way.