Experimental Comparison of Bluetooth and WiFi Signal Propagation for Indoor Localisation

Systems for indoor positioning using radio technologies are largely studied due to their convenience and the market opportunities they offer. The positioning algorithms typically derive geographic coordinates from observed radio signals and hence good understanding of the indoor radio channel is required. In this paper we investigate several factors that affect signal propagation indoors for both Bluetooth and WiFi. Our goal is to investigate which factors can be disregarded and which should be considered in the development of a positioning algorithm. Our results show that technical factors such as device characteristics have smaller impact on the signal than multipath propagation. Moreover, we show that propagation conditions differ in each direction. We also noticed that WiFi and Bluetooth, despite operating in the same radio band, do not at all times exhibit the same behaviour.

Towards Self-Learning Radio-Based Localization Systems

Location-awareness indoors will be an inseparable feature of mobile services/applications in future wireless networks. Its current ubiquitous availability is still obstructed by technological challenges and privacy issues. We propose an innovative approach towards the concept of indoor positioning with main goal to develop a system that is self-learning and able to adapt to various radio propagation environments. The approach combines estimation of propagation conditions, subsequent appropriate channel modelling and optimisation feedback to the used positioning algorithm. Main advantages of the proposal are decreased system set-up effort, automatic re-calibration and increased precision.

Streit um das Minarett. Zusammenleben in der religiös pluralistischen Gesellschaft

Der Bau von Minaretten und die daran sichtbar werdende Präsenz des Islam in Europa lösen Kontroversen aus, die in der Schweiz bis zu einer Volksinitiative zum Verbot von Minaretten geführt haben. Das vorliegende Buch thematisiert erstmals die wichtigsten Aspekte der Kontroverse: Was sind die Motive und die rechtlichen Rahmenbedingungen für den Bau von Minaretten? Warum konnte die Minarett-Initiative zustande kommen und worin besteht ihre Problematik? Wie sind die Argumente der Minarett-Gegner zu bewerten und welche Rolle spielen die Kirchen in der Minarett-Diskussion? Welche Lösungen gibt es für Minarett-Konflikte und welches sind die Regeln für das Zusammenleben in der religiös pluralistischen Gesellschaft? Diese Fragen werden aus juristischer, soziologischer, islamwissenschaftlicher und theologischer Perspektive diskutiert. Das Buch richtet sich sowohl an politisch Interessierte als auch an Fachleute.