Privacy in Indoor Positioning Systems: A Systematic Review

Preprint version of the paper entitled “Privacy in Indoor Positioning Systems: A Systematic Review”, presented in the 2020 International Conference on Localization and GNSS (ICL- GNSS). This article presents a systematic review of pri- vacy in indoor positioning systems. The selected 41 articles on location privacy preserving mechanisms employ non-inherently private methods such as encryption, k-anonymity, and differential privacy. The 15 identified mechanisms are categorized and summarized by where they are processed: on device, during transmission, or at a server. Trade-offs such as calculation speed, granularity, or complexity in set-up are identified for each mechanism. In 40% of the papers, some trade-offs are minimized by combining several methods into a hybrid solution. The combinations of mechanisms and their levels of offered privacy are suggested based on a series of user mobility cases.The authors gratefully acknowledge funding from European Union's Hori- zon 2020 Research and Innovation programme under the Marie Skłodowska Curie grant agreement No. 813278 (A-WEAR: A network for dynamic wear- able applications with privacy constraints, http://www.a-wear.eu/). J. Torres- Sospedra acknowledges funding from Ministerio de Ciencia, Innovacio ́n y Universidades (INSIGNIA, PTQ2018-009981)