# Fingerprinting-Based Indoor Localization Using Interpolated Preprocessed CSI Phases and Bayesian Tracking

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## Abstract

**:**

## 1. Introduction

## 2. Choice of Fingerprints

#### 2.1. Channel State Information

#### 2.2. Phase Information

#### 2.3. Phase Differences

## 3. Problem Description

**Problem**

**1.**

## 4. Proposed Positioning Method

#### 4.1. Fingerprint Modeling

#### 4.2. Static Positioning

#### 4.3. Dynamic Positioning

#### 4.3.1. Prediction

#### 4.3.2. Update

#### 4.3.3. Final Step

## 5. Experiments

#### 5.1. Static Positioning

#### 5.2. Dynamic Positioning

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**(

**Left**) Complex values, in polar coordinates, corresponding to subcarrier $m=1$ of 100 raw channel state information (CSI) measurements. (

**Right**) The same values after phase calibration.

**Figure 2.**(

**Left**) Compensated CSI phase at three adjacent positions. (

**Right**) Phase differences at the same positions.

**Figure 3.**Empty room layout for method comparison. The wireless access point is placed in the lower-left corner.

**Figure 4.**First entry of the averaged fingerprint ${\overline{g}}_{i}$ (dots) and the value yield by the model $\widehat{h}(p,\widehat{\alpha})$.

**Figure 5.**Office layout for method comparison. The wireless access point is placed in the upper-right corner, and rectangles represent desks.

**Figure 9.**Comparison of the dynamic positioning results yield by particle filtering and our proposed dynamic positioning method.

Methods | Mean Error [meters] | Minimum Error [meters] |
---|---|---|

Static positioning | 1.0970 | 0.3196 |

PhaseFi | 1.4722 | 0.5021 |

FILA | 2.3825 | 0.5511 |

DeepFi | 2.0283 | 0.3210 |

Methods | Mean Error [meters] | Minimum Error [meters] |
---|---|---|

Static positioning | 1.4551 | 0.2763 |

PhaseFi | 1.8722 | 0.4395 |

FILA | 2.5826 | 0.4863 |

DeepFi | 2.6770 | 1.0355 |

Methods | Mean Error [meters] | Maximum Error [meters] |
---|---|---|

Static positioning | 0.9879 | 2.4325 |

Particle filter | 1.6475 | 2.8131 |

Dynamic positioning | 0.4602 | 1.0706 |

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## Share and Cite

**MDPI and ACS Style**

Wang, W.; Marelli, D.; Fu, M.
Fingerprinting-Based Indoor Localization Using Interpolated Preprocessed CSI Phases and Bayesian Tracking. *Sensors* **2020**, *20*, 2854.
https://doi.org/10.3390/s20102854

**AMA Style**

Wang W, Marelli D, Fu M.
Fingerprinting-Based Indoor Localization Using Interpolated Preprocessed CSI Phases and Bayesian Tracking. *Sensors*. 2020; 20(10):2854.
https://doi.org/10.3390/s20102854

**Chicago/Turabian Style**

Wang, Wenxu, Damián Marelli, and Minyue Fu.
2020. "Fingerprinting-Based Indoor Localization Using Interpolated Preprocessed CSI Phases and Bayesian Tracking" *Sensors* 20, no. 10: 2854.
https://doi.org/10.3390/s20102854