A base station (eNB) determines device-to-device (D2D) transmission parameters for signal transmission over a D2D communication link between a first user equipment (UE) device and a second UE device. The eNB instructs the first UE device to transmit a reference signal that is received by the second UE device. The second UE device reports D2D channel characteristic information indicative of the received reference signal. Based on the D2D channel characteristic information, the base station determines the D2D transmission parameters and provides the parameters to the first UE device.