D2D Neighbor Discovery and Resource Scheduling through Demodulation Reference Signal

3GPP has recently accelerated the standardization process for Device-to-Device communications. Sidelink, which refers to the radio link between two user equipments (UEs), is a major update in 3GPP Release 12. In this paper, we will first introduce sidelink related structures and procedures in Release 12. Based on basic LTE signaling schemes, we propose methods of using demodulation reference signal (DMRS), which is used as reference signal in both uplink and sidelink, for advance D2D neighbor discovery and resource scheduling of D2D transmissions. Our study shows that reference signal of normal LTE channels can be well exploited to facilitate the newly proposed sidelink communications.