In two words, according to the patent, when a cellphone is almost out of battery all non-vital functionalities will be turned off and instead of the standard radio chip it will use Bluetooth to comminicate with the network. SMS and other very basic features will be enabled. No calls, apparently. The device will use other nearby devices as proxies. Devices must accept to be proxies, of course.
I am sure many will be concerned about privacy and actually I would be concerned myself.
I can think of services in the city, by mobile operators, that would install little “bluetooth cells” to help you stay connected…. For an extra price, of couse!
Funny technology, anyway.