Wakeup-over-Wifi possible?

[wifitier]

I'm wondering if there is a way to set an ESP into deepsleep, so it draws as less power as possible and wake it up by sending a special unicast signal to it? I'm thinking of something like an SSID beacon which is only broadcasted if the ESP should wakeup, connect, exchange some data and goes back to sleep again until it receives the beacon again.

[WiFive]

No, the reason it uses less power is because the radio and cpus are off.