NFC smart tag to trigger bluetooth?

[taltamir]

I was reading the new Nexus S review on anandtech and noticed that NFC takes insignificant amounts of powers.
Well, bluetooth does take a significant amount of power... would it be practical to have bluetooth devices with an NFC tag whose sole purpose is to turn on bluetooth and couple the devices? It would be a lot easier to just wave the phone over the headset rather then manually turning it on and connecting every time...

Is my idea practical? is it already being worked on?

 

[sjwaste]

Sounds good in principle, but I don't know much about bluetooth. When a device is unpaired, how much power does bluetooth consume? If there's a very low power mode that maybe takes a single poke to wake up the rest of the subsystem, it might already be good enough.

Using the iPhone 4 as an example of great battery life, my wife leaves bluetooth and wifi on all the time on hers, and she still doesn't have to charge it every day.

That said, it would be cool if there was something totally passive to wake up bluetooth. Something like RFID or NFC (isn't RFID just a subtype?), where if the other device reads a tag it identifies as "paired" it bounces something to wake up the bluetooth subsystem. A head unit, which wouldn't have to worry about power, could wake up a cell phone, which does.