I also wonder about the LMIC stack as published by @Thomas on github. To make it suitable for battery operation I guess one needs to implement hal_sleep() in hal.ccp for the microcontroller on which the stack is running? Taking into account possible wakeup events like from the SX127x or other peripherals like sensors?
Some specific LMIC implementations actually do provide an implementation of this function for a specific microcontroller. Has anyone over here already done such a thing? (before I start re-inventing the wheel ).