Real-time Outdoor Localization Using Radio Maps: A Deep Learning Approach

Global Navigation Satellite Systems typically perform poorly in urban environments, where the likelihood of line-of-sight conditions between devices and satellites is low. Therefore, alternative location methods are required to achieve good accuracy. We present LocUNet: A convolutional, end-to-end trained neural network (NN) for the localization task, which is able to estimate the position of a user from the received signal strength (RSS) of a small number of Base Stations (BS). Using estimations of pathloss radio maps of the BSs and the RSS measurements of the users to be localized, LocUNet can localize users with state-of-the-art accuracy and enjoys high robustness to inaccuracies in the estimations of radio maps. The proposed method does not require generating RSS fingerprints of each specific area where the localization task is performed and is suitable for real-time applications. Moreover, two novel datasets that allow for numerical evaluations of RSS and ToA methods in realistic urban environments are presented and made publicly available for the research community. By using these datasets, we also provide a fair comparison of state-of-the-art RSS and ToA-based methods in the dense urban scenario and show numerically that LocUNet outperforms all the compared methods. Ron Levie is with the Faculty of Mathematics, Technion - Israel Institute of Technology, 3200003 Haifa, Israel (e-mail: levieron@technion.ac.il). Gitta Kutyniok is with the Department of Mathematics, LMU Munich, 80331 München, Germany, and also with the Department of Physics and Technology, University of Tromsø, 9019 Tromsø, Norway (e-mail: kutyniok@math.lmu.de). Giuseppe Caire is with the Institute of Telecommunication Systems, TU Berlin, 10623 Berlin, Germany (e-mail: caire@tuberlin.de). A short version of this paper was presented in the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2022) in Singapore [1]. The location information of a User Equipment (UE) is essential for many current and envisioned applications that range from emergency 911 services [2], autonomous driving [3], intelligent transportation systems [4], proof of witness presence [5], 5G networks [6], to social networks, asset tracking and advertising [7], just to name a few. In urban environments, Global Navigation Satellite Systems (GNSS) alone may fail to provide a reliable localization estimate due to the lack of line-of-sight conditions between the UE and the GNSS satellites [8]. In addition, the continuous reception and detection of GNSS signals is one of the dominating factors in battery consumption for hand-held devices.