An Information-Based Approach to Precision Analysis of Indoor WLAN Localization Using Location Fingerprint

Mu Zhou,Feng Qiu,Wei He,Haibo Wu,Qiao Zhang,Zengshan Tian

doi:10.3390/e17127859

Abstract

In this paper, we proposed a novel information-based approach to precision analysis of indoor wireless local area network (WLAN) localization using location fingerprint. First of all, by using the Fisher information matrix (FIM), we derive the fundamental limit of WLAN fingerprint-based localization precision considering different signal distributions in characterizing the variation of received signal strengths (RSSs) in the target environment. After that, we explore the relationship between the localization precision and access point (AP) placement, which can provide valuable suggestions for the design of the highly-precise localization system. Second, we adopt the heuristic simulated annealing (SA) algorithm to optimize the AP locations for the sake of approaching the fundamental limit of localization precision. Finally, the extensive simulations and experiments are conducted in both regular line-of-sight (LOS) and irregular non-line-of-sight (NLOS) environments to demonstrate that the proposed approach can not only effectively improve the WLAN fingerprint-based localization precision, but also reduce the time overhead.

Highlights

In the recent decade, there has been a growing interest in indoor localization techniques, which are based on existing indoor wireless communication infrastructures and devices
The simulated annealing algorithm (SA) [24,25] is used to search the optimal access point (AP) locations, which correspond to the lowest fundamental limit of localization precision
We clarify that the three main contributions of this paper are that: (i) the Fisher information matrix (FIM) is used to derive the fundamental limit of indoor wireless local area network (WLAN) localization precision; (ii) the theoretical analysis towards the relationship between the localization errors and signal distributions is presented; and (iii) the SA algorithm is selected to search the optimal AP locations, which correspond to the lowest fundamental limit of localization precision

Summary

Introduction

There has been a growing interest in indoor localization techniques, which are based on existing indoor wireless communication infrastructures and devices. Due to the implementation ease and cost efficiency [1,2], the indoor wireless local area network (WLAN) fingerprint-based localization approach is preferred compared to the conventional trilateration localization approaches, which are compromised by the propagation path loss, multi-path fading and environmental shadowing. As far as we know, there are generally two phases involved in WLAN fingerprint-based localization [3,4,5,6], namely the off-line phase and on-line phase. In the off-line phase, the fingerprint database is built based on the received signal strength (RSS) measurements, which are associated with the calibrated reference points (RPs) in the target environment. In the on-line phase, the target locations are estimated by the matching from the newly-recorded RSS measurements against the pre-built fingerprint database to estimate the target locations [7]. To the best of our knowledge, there are very few works focusing on the theoretical analysis of the WLAN fingerprint-based localization precision, but the fundamental limit of localization precision can help greatly in AP placement optimization to achieve the highly-precise localization purpose

Objectives

Results

Discussion

Conclusion