Radio Fingerprint Research Articles

Construction of indoor WiFi fingerprint map based on ray tracing and Gaussian process regression

Abstract In traditional indoor robot positioning, SLAM sensors such as vision and lidar are commonly relied upon. However, achieving precise indoor Wireless Fidelity (WiFi) positioning and navigation for mobile robots, without the necessity of SLAM sensors, requires the construction of a high-precision wireless fingerprint map. To tackle this challenge, we suggest a technique for building indoor WiFi fingerprint maps using ray tracing and Gaussian process regression (GPR). This method involves simulating the propagation status of indoor WiFi signals using a ray tracing algorithm, resulting in a simulated WiFi fingerprint map. Additionally, we employ a mobile robot to collect real values of sparse WiFi fingerprints. These simulated and real-world data are then integrated through GPR to produce a comprehensive WiFi fingerprint map. To validate our approach, we evaluate it using three positioning algorithms in an indoor environment. Experimental results demonstrate that our method achieves a positioning accuracy of 69.30cm for indoor mobile robots, underscoring its effectiveness in constructing indoor WiFi fingerprint maps and paving the way for robot navigation in indoor environments. This research represents a significant advancement in the provision of high-precision WiFi fingerprint maps.

Fingerprint localisation for fine‐scale wildlife tracking using automated radio telemetry

Abstract Automated radio telemetry systems are one of the most widely applicable methods for tracking wildlife at fine spatiotemporal scales. A growing trend is for these systems to apply large networks of receivers to detect radio signal strength (RSS) from radio‐tagged individuals. Analytical methods to derive position estimates using RSS localisation, however, are relatively underdeveloped in the field of wildlife tracking. Here, we apply approaches from indoor positioning systems to develop a new method, radio fingerprinting, for localising radio‐tagged animals in structurally complex, outdoor environments. This method characterises the RSS patterns at known locations to generate a radio map of the study area, which is then used to predict the location of new RSS patterns. We conducted field tests to evaluate the localisation accuracy of radio fingerprinting relative to multilateration, a commonly used method for RSS localisation. To do so, we established an experimental receiver network covering multiple habitat types and compared the localisation accuracy of radio fingerprinting to multilateration. Additionally, we evaluated how a variety of features characteristic of typical tracking data sets affected the accuracy of both methods. While both methods had a similar median error under ideal conditions (~30 m), radio fingerprint localisation method offered several advantages over multilateration. Multilateration localisation estimates were highly affected by missed detections from the nearest receiver to the test point, which occurred in 30% of cases. In these cases, the median error was 103 m, over a 3.5‐fold increase. Distance to the nearest receiver also biased multilateration estimates with error increasing as the distance increased. Additionally, errors from multilateration estimates were higher in more densely vegetated areas. In contrast, fingerprinting position estimates were largely robust to each of these scenarios. Automated radio telemetry enables the fine‐scale, continuous tracking of range‐resident animals. We present radio fingerprinting as a localisation method in outdoor environments where standard localisation methods are error‐prone due to habitat heterogeneity and missed detections. This approach can be applied to any automated radio telemetry hardware and to any study system where a radio map can be generated.

Recurrent DQN for radio fingerprinting with constrained measurements collection

In this paper, we address the problem of fingerprinting-based radio localization with a particular focus on the measurements collection part. We consider the crucial circumstance where the operator that builds the fingerprinting map by collecting measurements can only travel a limited distance. We propose an iterative formulation that increases the accuracy of the position prediction task by using a recurrent deep reinforcement learning algorithm. Numerical results on a real dataset show the effectiveness of the proposed method, and the comparison with other measurement collection strategies corroborates its value.

RIS-Aided Wireless Fingerprinting Localization Based on Multilayer Graph Representations

RIS-Aided Wireless Fingerprinting Localization Based on Multilayer Graph Representations

Distributed Reconfigurable Intelligent Surfaces–Enabled Indoor Localization Based on Wireless Fingerprinting

Distributed Reconfigurable Intelligent Surfaces–Enabled Indoor Localization Based on Wireless Fingerprinting

Multidomain Transfer Ensemble Learning for Wireless Fingerprinting Localization

Multidomain Transfer Ensemble Learning for Wireless Fingerprinting Localization

A New Distance Metric Based on Bias-Variance Tradeoff for Wireless Fingerprinting

A New Distance Metric Based on Bias-Variance Tradeoff for Wireless Fingerprinting

Exploiting Radio Fingerprints for Simultaneous Localization and Mapping

Simultaneous localization and mapping (SLAM) is paramount for unmanned systems to achieve self-localization and navigation. It is challenging to perform SLAM in large environments, due to sensor limitations, complexity of the environment, and computational resources. We propose a novel approach for localization and mapping of autonomous vehicles using radio fingerprints, for example wireless fidelity or long term evolution radio features, which are widely available in the existing infrastructure. In particular, we present two solutions to exploit the radio fingerprints for SLAM. In the first solution—namely Radio SLAM, the output is a radio fingerprint map generated using SLAM technique. In the second solution—namely Radio+LiDAR SLAM, we use radio fingerprint to assist conventional LiDAR-based SLAM to improve accuracy and speed, while generating the occupancy map. We demonstrate the effectiveness of our system in three different environments, namely outdoor, indoor building, and semi-indoor environment .

JoLo: Multi-Device Joint Localization Based on Wireless Data Fusion

Many indoor localization techniques have been widely investigated. As the proportion of people with multiple mobile devices is increasing, an interesting research challenge arising from this growth is how to integrate data from multiple devices carried by a mobile user for localizing her/him. This work designs a multi-device joint localization system, called JoLo, to realize the idea using a group of off-the-shelf mobile devices carried by a user. The proposed system collects wireless fingerprints at the predefined training locations in the environment. Then, the system fuses the real-time wireless measurements observed by the multiple devices of a user into a summary list for localization reference. Finally, three fusion-based positioning algorithms are proposed to determine the users location based on the fused summary list. The three proposed algorithms reduce mean distance errors in localization to less than one meter in a lab environment. One of the fusion-based algorithms, namely cluster-based DF algorithm, can even improve the performance by 50% on average compared to the existing single-device localization techniques.

DeepWiPos: A Deep Learning-Based Wireless Positioning Framework to Address Fingerprint Instability

Wireless fingerprint localization technologies have drawn significant attention because of their ubiquitous infrastructure and low energy consumption. However, they often suffer from the Received Signal Strength (RSS) instability (i.e., RSS variations across heterogeneous devices and RSS fluctuations over time) and fingerprint spatial ambiguity issues. Although various deep learning-based methods have been proposed recently, most of them only pursue remarkable accuracy in an ideal environment and escape the above-mentioned problems. The co-existence of these factors would make most existing methods suboptimal or invalid when applied in real scenarios. In this paper, to address the RSS instability, we define the fingerprint spatial gradient (FSG), which can convert the vulnerable and unstable fingerprints to stable relative values but lose absolute information for positioning. Next, to relieve the fingerprint instability and model the temporal sequential dependencies in a trajectory, we propose a Long Short-Term Memory network (LSTM)-based framework to fuse FSG and RSS, where an attention module is used to guide the fusion according to their contributions to the result. Finally, the beam search strategy is used to search for the optimal solution from outputs of the LSTM, eliminating the spatial ambiguity of fingerprints. The experiments show that DeepWiPos reduces average positioning error by 23.44% and 22.18% on Bluetooth and Wi-Fi, respectively when compared with the state-of-the-art.

Adaptive radio map reconstruction via adversarial wireless fingerprint learning

Adaptive radio map reconstruction via adversarial wireless fingerprint learning

An Improved Lightweight Two-Factor Authentication Protocol for IoT Applications

The Internet of Things (IoT) is defined as a network of connected objects or devices that gather information and share or exchange them through communication systems. In many applications, maintaining the privacy and security of the exchanged data is of great importance. Therefore protecting sensitive data against security threats is a major concern in IoT applications. Using Multi-factor authentication protocols is an efficient solution to provide these features. Recently, a two-factor authentication protocol using Physical Unclonable Functions (PUFs) and wireless fingerprints has been proposed by Aman et al. In this paper, we first analyze Aman et al.'s protocol and discuss its weaknesses and vulnerabilities. Then, we propose an improved two-factor authentication protocol to provide strong mutual authentication and overcome the mentioned issues. The informal security analysis of the proposed scheme demonstrates that it is resistant to several well-known attacks. We also perform a security analysis of the proposed scheme using Burrows-Abadi-Needham (BAN) logic. We further evaluate the proposed protocol in terms of computational complexity and security features. The results demonstrate that our scheme has significantly better computational efficiency and provides better security features compared to Aman et al.'s protocol.

Graph-Based Radio Fingerprint Augmentation for Deep-Learning-Based Indoor Localization

Indoor localization plays an essential role in enabling location-based services (LBSs) for sensor networks wherever global navigation satellite systems (GNSSs) are unreachable. For deep-learning-based indoor localization methods, radio data are extremely important for accurate fingerprinting-based localization but are often incomplete or are not temporally and spatially sufficient for data acquisition. Motivated by the goal of leveraging existing radio fingerprints to further improve localization accuracy, in this article, we propose a graph-based fingerprint augmentation method for deep-learning-based indoor localization. In this method, by modeling each reference point (RP) as a vertex of a graph and its radio data as graph signals, we develop a graph signal model where virtual RPs are introduced as missing vertices with missing radio data. Then, we explore the underlying spatial structure among all the real and virtual RPs to find the graph Laplacian with which to reconstruct the radio fingerprints by a semisupervised graph interpolation. On this basis, some deep neural networks and convolutional neural networks (DNNs and CNNs) trained by the reconstructed radio fingerprints are developed for indoor localization. Experiments on real datasets reveal the performance gain of the proposed fingerprint augmentation method in localization accuracy, showing the potential of graph-based data augmentation for deep-learning-based indoor localization.

Radio fingerprinting for anomaly detection using federated learning in LoRa-enabled Industrial Internet of Things

Long Range (LoRa) communications are gaining popularity in the Industrial Internet of Things (IIoT) domain due to their large coverage and high energy efficiency. However, LoRa-enabled IIoT networks are susceptible to cyberattacks mainly due to their wide transmission window and freely operated frequency band. This has led to several categories of cyberattacks. However, existing anomaly detection systems are inefficient in detecting particularly impersonation attacks due to the dense deployment, heterogeneous IIoT devices and manufacturers involved.In this work, we introduce Hawk, a distributed anomaly detection system for detecting compromised devices in LoRa-enabled IIoT. Hawk first measures a device-type specific physical layer feature, Carrier Frequency Offset (CFO) and then leverages the CFO for fingerprinting the device, and consequently detecting anomalous deviations in the device’s CFO behavior, potentially caused by adversaries. To aggregate the device-type specific CFO behavior profile efficiently, Hawk uses federated learning, a distributed machine learning approach. To the best of our knowledge, Hawk is the first to utilise a federated learning method for anomaly-based intrusion detection in LoRa-enabled IIoT. We perform extensive experiments on a real-world dataset collected using 60 LoRa devices, primarily to assess the effectiveness of Hawk against emerging new and unknown attacks. The results show that Hawk improves the detection accuracy by more than 8% compared to the state-of-the-art solutions. Additionally, Hawk reduces the storage overhead by more than 40%, and exhibits significant robustness against cyberattack.

An Enhanced Indoor Positioning Solution Using Dynamic Radio Fingerprinting Spatial Context Recognition

Radio fingerprinting positioning is widely used for smartphone location-based services and Internet of Things applications given its high availability and low cost. Radio fingerprinting-based algorithms, however, are subject to the forced matching problem and often yield estimated positions even when a user is actually located outside of the fingerprint region. A positioning solution in multistory buildings should be able to locate positions accurately on the current floor; but these methods may generate unreasonable positioning trajectories, such as irrationally passing through a wall, when fingerprinting positioning is fused the with inertial measurement unit to further improve the accuracy. A radio map must be surveyed dynamically on-the-move, as a dynamic fingerprint, to reduce the time costs and on-site workload. Unlike static fingerprint-based methods, dynamic fingerprinting samples are sparse. Thus, we propose an enhanced indoor positioning solution using spatial context knowledge, extracted from the sparse dynamic fingerprints. In the offline stage of radio map calculation, we extract the dynamic fingerprint features and store them in a spatial features database to reduce the computational time and storage space complexity. The proposed floor detection, region recognition, and path correction algorithms identify the online spatial contexts from the stored spatial features to improve positioning performance. This solution was applied on smartphones combining WiFi and Bluetooth low-energy radio signals in two typical scenarios. The experimental results show that the floor detection accuracy reached 99% while region recognition accuracy reached 90.75%. The positioning path correction method enhances the accuracy of smartphone indoor positioning from 3.27 to 2.56 m.

Low-Cost Indoor Wireless Fingerprint Location Database Construction Methods: A Review

The fingerprint positioning has achieved remarkable results in indoor localization tasks, but the method usually relies on a large amount of fingerprint data to build a fingerprint database, and the amount and diversity of fingerprint data will directly affect the effectiveness of fingerprint positioning. Since fingerprint acquisition is limited and disturbed by space and time, it consumes a lot of labor and time costs to collect fingerprint data in the localization environment, and wireless fingerprint data is time-sensitive and environment-dependent, and changes in the localization environment will reduce the usability of the existing fingerprint database. The complex and repetitive fingerprint acquisition work seriously affects the feasibility of practical deployment of fingerprint positioning systems in the positioning environment. Therefore, the study of low-cost wireless fingerprint database construction methods has become an inevitable part of promoting the widespread deployment of indoor fingerprint positioning systems. In this paper, we introduce the traditional data augmentation-based approach and the advanced machine learning model-based approach, systematically presenting the underlying models and algorithms of both. The former reviews the application of two traditional data enhancement methods, namely channel propagation models and interpolation or regression, to the construction of low-cost wireless fingerprint databases, while the latter taps into techniques for reducing the cost of fingerprint database construction by combining generative adversarial networks and small-sample learning models with the indoor localization domain. Finally, we discuss the current challenges and future research directions for achieving high-performance indoor localization based on low-cost wireless fingerprint databases, and suggest some useful research guidelines.

PAST-AI: Physical-Layer Authentication of Satellite Transmitters via Deep Learning

Physical-layer security is regaining traction in the research community, due to the performance boost introduced by deep learning classification algorithms. This is particularly true for sender authentication in wireless communications via radio fingerprinting. However, previous research mainly focused on terrestrial wireless devices while, to the best of our knowledge, none of the previous work considered satellite transmitters. The satellite scenario is generally challenging because, among others, satellite radio transducers feature non-standard electronics (usually aged and specifically designed for harsh conditions). Moreover, the fingerprinting task is specifically difficult for Low-Earth Orbit (LEO) satellites (like the ones we focus in this paper) since they feature a low bit-rate and orbit at about 800 Km from the Earth, at a speed of around 25,000 Km/h, thus making the receiver experiencing a down-link with unique attenuation and fading characteristics. In this paper, we investigate the effectiveness and main limitations of AI-based solutions to the physical-layer authentication of LEO satellites. Our study is performed on massive real data—more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100M$ </tex-math></inline-formula> I-Q samples—collected from an extensive measurements campaign on the IRIDIUM LEO satellites constellation, lasting 589 hours. Our results show that Convolutional Neural Networks (CNN) and autoencoders (if properly calibrated) can be successfully adopted to authenticate the satellite transducers, with an accuracy spanning between 0.8 and 1, depending on prior assumptions. However, the relatively high number of I-Q samples required by the proposed methodology, coupled with the low bandwidth of satellite link, might prevent the detection of the spoofing attack under certain configuration parameters.

BLS-Location: A Wireless Fingerprint Localization Algorithm Based on Broad Learning

With the rapid growth in the demand for location-based services in indoor environments, wireless fingerprint localization has attracted increasing attention because of its high precision and easy implementation. However, an effective method does not exist owing to the problems of data loss, noise interference in the fingerprint database, and being time-consuming during the offline training phase. Therefore, this paper presents a novel indoor wireless fingerprint localization algorithm, termed BLS-Location, based on a broad learning system (BLS) that utilizes channel state information (CSI) to overcome the aforementioned problems. It includes an offline training phase and an online localization phase. In the offline training phase, the Kalman filter and the expectation-maximization (EM) algorithm are utilized for completing and denoising the data. Moreover, principal component analysis (PCA) is used to reconstruct the CSI data to reduce complexity and train the weights by BLS. In the online localization phase, we employ a novel probabilistic method based on the regression results of BLS to obtain the estimated location. The experimental results show that BLS-Location can significantly reduce the training time with a high accuracy, compared to several machine learning algorithms and four existing methods in two representative indoor environments.

1921. Leveraging Bluetooth Low-Energy Technology to Improve Contact Tracing in Healthcare Settings during the COVID-19 Pandemic

Abstract Background COVID-19 rapidly evolved into a global pandemic. Contact tracing with isolation and quarantine contribute to epidemic control but they are time consuming, costly and may be incomplete. We set out to assess the usability and performance characteristics of Bluetooth Low-Energy (BLE) wireless technology for indoor localization applied to contact tracing in healthcare settings. Methods Consented healthcare workers (HCW) from 2 designated COVID-19 wards (one intensive care unit (ICU) and one medical ward) were equipped with coin-sized BLE- emitting beacons. The signal was captured by small embedded computers (anchors) placed at designated locations, time-stamped and transmitted to an edge server via secure Wi-Fi where data were stored and real time contact algorithms were run (Fig.1). We developed experiments mimicking clinical scenarios and tested indoor localization during observed clinical activity for 6 months. We constructed our algorithms based on room structure (e.g. open spaces vs computer rooms) and activity characteristics (e.g. rounding in a large group vs 2 healthcare workers sitting together). We used 1) radio fingerprint localization where an initial virtual radio map was developed, 2) semantic localization which carries additional information such as proximity to a computer to define indirect transmission via fomites, and 3) clustering contact tracing to identify individuals rounding together. Close contact was defined as per the CDC guidelines. Fig. 1System configuration Results Consent rate was 43.3% with 187 HCW enrolled in the study. Consent rate was higher in the ICU and among attendings. All participants were compliant with wearing the beacons for the duration of the study. The performance characteristics for contact tracing using fingerprinting methods were AUROC 0.93, AUPRC 0.96, sensitivity 0.9, specificity 0.77 with F1 score of 0.89 and overall accuracy of 0.85. The clustering contact tracing registered a sensitivity of 0.86, specificity 0.89, F1 score 0.91 and accuracy 0.87. Computation time necessary to generate a list of close contacts as per specified criteria was less than 30 minutes. Conclusion We have developed and tested a reliable and accurate, low-cost and easily deployable system based on BLE technology to improve contact tracing among healthcare workers. Disclosures M Cristina Vazquez Guillamet, MD, AUPH: Stocks/Bonds|BNGO: Stocks/Bonds|OCGN: Stocks/Bonds|SESN: Stocks/Bonds.

Hybrid Wi-Fi and BLE Fingerprinting Dataset for Multi-Floor Indoor Environments with Different Layouts

Indoor positioning has garnered significant interest over the last decade due to the rapidly growing demand for location-based services. As a result, a multitude of techniques has been proposed to localize objects and devices in indoor environments. Wireless fingerprinting, which leverages machine learning, has emerged as one of the most popular positioning approaches due to its low implementation cost. The prevailing fingerprinting-based positioning mainly utilizes wireless fidelity (Wi-Fi) and Bluetooth low energy (BLE) signals. However, the RSS of Wi-Fi and BLE signals are very sensitive to the layout of the indoor environment. Thus, any change in the indoor layout could potentially lead to severe degradation in terms of localization performance. To foster the development of new positioning methods, several open-source location fingerprinting datasets have been made available to the research community. Unfortunately, none of these public datasets provides the received signal strength (RSS) measurements for indoor environments with different layouts. To fill this gap, this paper presents a new hybrid Wi-Fi and BLE fingerprinting dataset for multi-floor indoor environments with different layouts to facilitate the future development of new fingerprinting-based positioning systems that can provide adaptive positioning performance in dynamic indoor environments. Additionally, the effects of indoor layout change on the location fingerprint and localization performance are also investigated.