In an embodiment, when device discovery signals are sent for the first time, positions of discovery resource elements for sending the device discovery signals, including time and/or frequency resources, are selected randomly.

In an embodiment, before sending the discovery signals for the first time, a UE measures signal interference condition or signal energy in discovery resources and determines the positions of the discovery resource elements for sending the discovery signals according to a minimal interference or minimal energy principle.

In an embodiment, time and/or frequency positions of the discovery resource elements for sending the device discovery signals for the first time are determined according to an UE identity, for example, a UE_ID. For example, if the discovery resource elements in the discovery resource period are numbered as 0?(N*K?1), then the determined positions of the discovery resource elements of the UE for sending the device discovery signals are numbered as mod(UE_ID,N*K). The serial numbers of the positions of the discovery resource elements are obtained in a frequency priority or time priority manner, and the UE identity may be an identity of the UE in an idle or connected state, including an International Mobile Subscriber Identification Number (IMSI), an Temporary Mobile Subscriber Identity (TMSI), a Radio Network Temporary Identity (RNTI) or a part of a field in the identities.