Demands for the low-power wide-area network (LPWAN) are increasing along with a growing market for low data-rate, long-range internet of things (loT) applications. Although many radios have been released for various LPWAN standards, such as LTE-M, NB-IoT, LoRa, Sigfox, and WiSUN, they are not suitable for always-on receive-standby operation due to the high DC power dissipation of the receiver (RX) (e.g., >10mW), mandating heavy synchronized duty-cycling. Therefore, LPWAN radios released so far are not suitable for the applications where events occur aperiodically and real-time response is essential.