Methods and apparatus for waveform design and signaling for energy harvesting (EH) in a wireless network are disclosed. In an example, a method includes receiving a control message including a contention-based backscattering configuration, determining parameters for transmitting a feedback within a contention-based transmission window based on the contention-based backscattering configuration, detecting feedback transmissions sent by other WTRUs within the contention-based transmission window, wherein each feedback transmission includes an EH capability indication, determining whether an EH capability detected from the feedback transmissions matches the EH capability of the WTRU, if a matched EH capability is detected from the feedback transmissions within the contention-based transmission window, delaying a transmission of the feedback, and if no matched EH capability is detected from the feedback transmissions within the contention-based transmission window, transmitting the feedback using the determined parameters.