Systems, methods and devices for low power channel access using a wake up radio are disclosed herein. In accordance with one exemplary embodiment, a method performed by a communication device includes: receiving a wake up signal at a wake up radio from a communication node at a receipt time, wherein the wake up signal indicates a node active time for a main radio to begin communicating with the communication node; determining a transition time between an initiation time for the main radio and a device active time, wherein the device active time is during the node active time; determining a delay time from the receipt time to the initiation time; initiating the main radio at the initiation time; and communicating with the communication node using the main radio during the device active time.