I. Introduction
The fifth generation (5G) of mobile communication networks are anticipated to provide a massive leap when compared to the existing networks in terms of system capacity, data throughputs, end-to-end latency, seamless coverage (via dense small cells), number of connected devices, network energy efficiency, etc. [1], [2]. Besides, highly accurate device positioning and location-aware communication are envisioned. The positioning accuracy is expected to be in the order of a meter or even sub-meter [3], [4]. Such a high-performance positioning is essential for new emerging applications and location-based services, including safety-critical applications, augmented reality [5], assisted living [6], healthcare and emergency services [4], etc. In addition, positioning information can be used as support for channel estimation or to perform beamforming by steering transmission towards a user (with known position), therefore reducing the beam search time.