Base station assisted neighbor discovery in device to device systems

Neighbor discovery is an essential prerequisite for any device-to-device (D2D) communication. Unlike ad-hoc networks, the base station (BS) in D2D networks may facilitate the neighbor discovery process. However, device-to-BS channel states or device locations are not enough to provide BS with information on the channel quality between the devices. Thus, due to the inherent uncertainty of link quality between devices, the BS-assisted neighbor discovery cannot be treated as typical scheduling problem. In this paper, we investigate the assisted directional neighbor discovery in D2D networks. We first formulate the scheduling problem as an integer optimization problem that captures the uncertainty. Then we propose a greedy based centralized scheduling to determine directional pilot transmission instances. We also propose a one-way randomized discovery, where we choose the directional transmission probabilities based on two techniques, an intuitive and an optimized methods. Finally, we provide simulation results that assess the performance the schemes.