This disclosure relates to Wi-Fi signaling in conjunction with cellular communication in unlicensed frequency bands for efficient co-existence. According to one embodiment, a cell may be established between a cellular base station and a wireless user equipment device on a frequency channel in an unlicensed frequency band. A cellular communication may be scheduled between the base station and the user equipment device. A Wi-Fi signal may be transmitted on the frequency channel in conjunction with the scheduled cellular communication. The Wi-Fi signal may indicate a length of the scheduled cellular communication using Wi-Fi signaling. The scheduled cellular communication may be performed via the cell.