A method and apparatus for offloading idle mode activities from one user equipment (UE) to another. A UE includes a cellular modem, a device-to-device (D2) communication modem, and a processor. The cellular modem performs idle mode activities during an idle mode. The processor controls the cellular modem and the D2D modem. The processor is configured to send information necessary for performing the idle mode activities to the secondary UE for offloading the idle mode activities of the primary UE to the secondary UE and put the cellular modem in a low power state or turn off the cellular modem during the idle mode. The processor wakes up the cellular modem to receive a paging message if a wake-up signal is received from the secondary UE.