Janis Werner∗, Mário Costa†, Aki Hakkarainen∗, Kari Leppaänen† and Mikko Valkama∗
* Tampere University of Technology, Finland
† Huawei Technologies, Finland
It is commonly expected that network densification will play an important role in achieving the capacity demands of 5G communication networks. While densification is introduced to improve the spectral efficiency and area-capacity, it also results in an infrastructure that is perfectly suitable for user node (UN) positioning. However, so far this compelling opportunity has not been clearly recognized in the literature. In this paper, we therefore propose to make “always on” positioning an integral part of 5G networks such that highly accurate UN position estimates are available at any given moment but without draining the UN batteries. We furthermore propose an extended Kalman filter (EKF) that tracks the UN position based on the fusion of direction of arrival (DoA) and time of arrival (ToA) estimates obtained at the access nodes (ANs) of the 5G network. Since ToA estimates are typically not useful for positioning unless the UN is synchronized with the network, we include a realistic clock model within the DoA/ToA EKF. This addition makes it possible to estimate the offset of the imperfect UN clock, along with the UN position. In an extensive analysis that is based on specific 5G simulation models, we then quantify the enormous potential of high accuracy positioning in 5G networks, in general, and the proposed DoA/ToA EKF, in particular. Moreover, we demonstrate that the proposed DoA/ToA EKF substantially outperforms the classical DoA-only EKF and is furthermore also able to handle practically extremely relevant situations where the DoA-only EKF fails to position the UN.
Published in the proceedings of IEEE Global Communications Conference (GLOBECOM) 2015
Videos and Demonstrations
Video 1
User position tracking example of the proposed joint DoA/ToA-EKF in comparison to the classical DoA-only EKF. Settings: T/Tf = 100, multiple LoS-AN map.