Synchronization signal design and hierarchical detection for the D2D sidelink

Abstract

Device-to-device (D2D) communication is considered as a key component in existing and future cellular networks. Safety and emergency applications must be served by the so-called ultra-reliable low-latency communication (URLLC). To this end, reliable fast synchronization and user identification are required for link establishment and dynamic topology estimation. In this work we propose a framework for sequence generation, which encapsulates additional information, e.g. the type of synchronization source used by a transmitting user, whether the user obtains this reference directly or over another user, etc. Such information allows the receiver to prioritize and accordingly weight different synchronization signals based on the source type and achieve thus faster and more reliable synchronization. Receiver-side and distributed synchronization algorithms are described and evaluated for typical D2D scenarios. It is shown that both receiver-side as well as global synchronization can be achieved with high accuracy.