US Patent 11184850 Bidirectional communication using a wake-up radio

A recipient electronic device that provides an acknowledgment is described. This recipient electronic device may include a main radio and a wake-up radio (WUR) that at least selectively transitions the main radio from a lower-power mode to a higher-power mode in response to a wake-up frame. During operation, the WUR receives a wake-up frame associated with an electronic device, e.g., a second or a sending device. Then, the WUR provides, in response to the wake-up frame, the acknowledgement intended for the electronic device. The wake-up frame may specify that an acknowledgement from the recipient electronic device to the electronic device is expected. For example, the wake-up frame may specify that the acknowledgement is communicated by the recipient electronic device using the WUR in the recipient electronic device. Moreover, the WUR may provide the acknowledgment while the main radio is in the lower-power mode.