Are all the Access Points necessary in WLAN-based indoor positioning?

Abstract

Wireless Local Area Networks are widely used for indoor localization purposes based on Received Signal Strength -based positioning algorithms, due to the increasing demands for Location-based Services indoors. A huge number of hearable Access Points can however increase the complexity of the positioning system and the difficulty of location estimation, since not all of the available Access Points carry useful or significant information. This paper focuses on Wireless Local Area Networks-based indoor location by taking into account the contribution of each hearable Access Point in the location estimation. Several criteria for Access Point selection are examined, and we will show what is the permissible reduction factor without a large deterioration in positioning performance and which criterion is optimal for use in Access Point removal. The fingerprinting estimation method and the deconvolution based path loss positioning approach are both addressed, and the results are based on a large measurement campaign covering five different buildings with several floors each, in two countries.