Method and apparatus for transmitting reference signal in device-to-device (D2D) communication

A method comprising:

• acquiring characteristic information used in selecting a target resource used to send a reference signal (RS), wherein the characteristic information comprises an identity of a first user equipment and an identity of a second user equipment in communication with the first user equipment;
• selecting, from a communication resource according to the characteristic information, the target resource;
• and
• sending either first information or second information to at least one of the first user equipment or the second user equipment, wherein the first information indicates the characteristic information, and wherein the second information indicates the target resource.

An apparatus comprising:

• a processor;
• and
• a memory coupled to the processor and storing programming instructions for execution by the processor to cause the apparatus to:
• determine a target resource in a communication resource according to a modulus value of characteristic information comprising an identity of the apparatus and an identity of a second user equipment in communication with the apparatus, wherein the target resource comprises at least one of a frequency domain resource of a reference signal (RS) or a cyclic shift (CS) of the RS;
• and
• transmitting, using the target resource to the second user equipment, the RS.

An apparatus comprising:

• a processor;
• and
• a memory coupled to the processor and storing programming instructions for execution by the processor to cause the apparatus to:
• acquire characteristic information used in selecting a target resource used to send a reference signal (RS), wherein the characteristic information comprises an identity of a first user equipment and an identity of a second user equipment in communication with the first user equipment;
• select, from a communication resource according to the characteristic information, the target resource;
• and
• send either first information or second information to at least one of the first user equipment or the second user equipment, wherein the first information indicates the characteristic information, and wherein the second information indicates the target resource.