Embodiments of the present disclosure provide a method of user equipment which performs cellular transmission via a serving base station. The method may comprise: sending a request message to the serving base station to request allocation of a resource for device-to-device (D2D) discovery transmission; receiving from the serving base station an indication message for indicating the allocated resource; and performing the D2D discovery transmission on the allocated resource while the cellular transmission is performed. The embodiments of the present disclosure further provide a method of a serving base station, user equipment, and a serving base station.
