A similar problem of mutual discovery between communication devices exists in D2D communication, that is, the UE performing the D2D communication needs first to implement discovery of its opposite UE, which is referred to as discovery of D2D communication, D2D discovery or device discovery in the embodiment. The D2D discovery is implemented by transmission and detection of a discovery signal. The discovery signal may be in the form of a sequence, such as a synchronization signal, a random access preamble, a reference signal and the like in a cellular network, the discovery signal may also be in other forms of a sequence having a similar structure, such as a Zadoff-Chu(ZC) sequence, Walsh codes and the like; the discovery signal may also be a packet or message with a specific modulation and encoding mode; and the discovery signal may also be in the form of combination of a sequence and a packet or in the form of a message. In the embodiment, for the sake of convenience of description, a physical channel for transmitting D2D discovery signals is named as Physical ProSe Discovery Channel (PPDCH). It should be noted that the name is not to be construed as an inappropriate limitation to the present disclosure.