Publications in Scientific Journals:

G. Retscher:
"Fundamental Concepts and Evolution of Wi-Fi User Localization: An Overview Based on Different Case Studies";
Sensors (invited), 2020 (2020), 20; 36 pages.

English abstract:
Indoor positioning poses a number of challenges, especially in large and complex buildings. Several effects, such as signal attenuation, signal fluctuations, interference, and multipath play a decisive role in signal propagation. The severity of each challenge depends on the method and technology adopted to perform user localization. Wi-Fi is a popular method because of its ubiquity with already available public and private infrastructure in many environments and the ability for
mobile clients, such as smartphones, to receive these signals. In this contribution, the fundamental
concepts and basics and the evolution ofWi-Fi as the most widely used indoor positioning technology are reviewed and demonstrated using four different conducted case studies. Starting from an analysis of the properties ofWi-Fi signals and their propagation, suitable techniques are identified. The mathematical models of location fingerprinting and lateration are consolidated and assessed as well as new technology directions and developments highlighted. Results of the case studies
demonstrate the capability of Wi-Fi for continuous user localization also in dynamic environments and kinematic mode where the user walks with a usual step speed. However, to achieve acceptable localization accuracy, calibration of the devices is required to mitigate the variance problems due to the device heterogeneity.

received signal strength RSS; round trip time RTT measurements; location fingerprinting; lateration; combination and fusion of techniques; positioning algorithms; indoor smartphone user localization

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

Electronic version of the publication:

Created from the Publication Database of the Vienna University of Technology.