Setting aside for the moment the environmental impact of battery disposal at that scale, nobody wants to take on the battery maintenance problem. have been off for an extended period of time will add significant overhead and set a lower bound on the energy used for communication. It is worth noting that synchronization is more challenging as the number of devices scales, especially into the thousands. Sensitivity is a measure of the minimum required received signal strength to achieve a target bit error rate of, usually, 10−3 or a packet