Robust Neighbor Discovery Through SideLink Demodulation Reference Signal for LTE ProSe Network

By introducing the Proximity Services (ProSe) functionalities in its 12th release, the 3rd Generation Partnership Project (3GPP) made possible the ability to perform device-to-device (D2D) communication in Long Term Evolution-Advanced (LTE-A) cellular network. Direct communication between nearby User Equipments (UEs) is then enabled through the newly introduced sidelink. This paper investigates neighbor discovery for D2D communication exploiting Demodulation Reference Signals (DMRS), which are associated with physical sidelink channels for coherent demodulation. By simply listening to its sidelink signal, a ProSe-enabled UE can identify its peers and initiate a direct link without any additional overhead. The study examines the properties of DMRS sequences and proposes a robust neighbor discovery scheme tailored to DMRS structure based on a power normalized correlation process. A reduction in the computational load required to establish a link between two neighbors is proposed and evaluated. Simulation results show that nearby users can be discovered with a reasonable complexity while achieving a high discovery accuracy.