Deep Neural Networks for Jamming and Interference Classification in 5G Physical Layer

The fifth generation (5G) of cellular networks is bringing major performance improvements and connecting new industries with wider application areas than the previous generations. The exposed nature of every wireless technology, including 5G, makes them vulnerable to being interfered. Interference can be intentional by jamming attacks or unintentional by other devices in the network. These physical layer threats can cause denial-of-service problems in the network. To ensure the security and availability of 5G communications, it is important to develop identification methods for jamming and interference. In this thesis, three deep learning (DL) approaches are proposed for classifying different jamming and interference models. To train and evaluate those DL approaches, a 5G spectrogram-related jamming and interference dataset is generated. The proposed DL architectures are convolutional neural network (CNN), long short-term memory (LSTM), and combined CNN-LSTM. The goal is to find out which DL model works the best and if there is a significant difference between two different classification tasks. Those tasks are binary and multi-class classifications. Binary classification denotes whether the input is jammed or not, whereas multi-class classification recognizes the type of the jamming model. CNN and CNN-LSTM results are almost identical with binary classification accuracies around 97% and multi-class classification accuracies around 90%. LSTM is notably worse with accuracies around 90% and 70% respectively. Overall, all models show sufficient performance, but CNN performs the best in terms of results and efficiency. Also, performance differences between the two classification tasks are not alarming, so either task is suitable for the proposed approaches

Deep Neural Network Solution for Detecting Intrusion in Network

In our experiment, we found that deep learning surpassed machine learning when utilizing the DSSTE algorithm to sample imbalanced training set samples. These methods excel in terms of throughput due to their complex structure and ability to autonomously acquire relevant features from a dataset. The current study focuses on employing deep learning techniques such as RNN and Deep-NN, as well as algorithm design, to aid network IDS designers. Since public datasets already preprocess the data features, deep learning is unable to leverage its automatic feature extraction capability, limiting its ability to learn from preprocessed features. To harness the advantages of deep learning in feature extraction, mitigate the impact of imbalanced data, and enhance classification accuracy, our approach involves directly applying the deep learning model for feature extraction and model training on the existing network traffic data. By doing so, we aim to capitalize on deep learning's benefits, improving feature extraction, reducing the influence of imbalanced data, and enhancing classification accuracy

Adversarial machine learning for cyber security

This master thesis aims to take advantage of state of the art and tools that have been developed in Adversarial Machine Learning (AML) and related research branches to strengthen Machine Learning (ML) models used in cyber security. First, it seeks to collect, organize and summarize the most recent and potential state-of-the-art techniques in AML, considering that it is a research branch in an unstable state with a great diversity of difficult to contrast proposals, which rapidly evolve but are quickly replaced by attacks or defenses with greater potential. This summary is important considering that the AML literature is far from being able to create defensive techniques that effectively protect a ML model from all possible attacks, and it is relevant to analyze them both in detail and with criteria in order to apply them in practice. It is also useful to find biases in state-of-the-art to be considered regarding the measurement of the attack or defense effectiveness, which can be addressed by proposing methodologies and metrics to mitigate them. Additionally, it is considered inappropriate to analyze AML in isolation, considering that the robustness of a ML model to adversarial attacks is totally related to its generalization capacity to in-distribution cases, to its robustness to out-of-distribution cases, and to the possibility of overinterpretation, using spurious (but statistically valid) patterns in the model that may give a false sense of high performance. Therefore, this thesis proposes a methodology to previously evaluate the exposure of a model to these considerations, focusing on improving it in progressive order of priorities in each of its stages, and to guarantee satisfactory overall robustness. Based on this methodology, two interesting case studies are chosen to be explored in greater depth to evaluate their robustness to adversarial attacks, perform attacks to gain insights about their strengths and weaknesses, and finally propose improvements. In this process, all kinds of approaches are used depending on the type of problem evaluated and its assumptions, performing exploratory analysis, applying AML attacks and detailing their implications, proposing improvements and implementation of defenses such as Adversarial Training, and finally creating and proposing a methodology to correctly evaluate the effectiveness of a defense avoiding the biases of the state of the art. For each of the case studies, it is possible to create efficient adversarial attacks, analyze the strengths of each model, and in the case of the second case study, it is possible to increase the adversarial robustness of a Classification Convolutional Neural Network using Adversarial Training. This leads to other positive effects on the model, such as a better representation of the data, easier implementation of techniques to detect adversarial cases through anomaly analysis, and insights concerning its performance to reinforce the model from other viewp

Multifunction Radios and Interference Suppression for Enhanced Reliability and Security of Wireless Systems

Wireless connectivity, with its relative ease of over-the-air information sharing, is a key technological enabler that facilitates many of the essential applications, such as satellite navigation, cellular communication, and media broadcasting, that are nowadays taken for granted. However, that relative ease of over-the-air communications has significant drawbacks too. On one hand, the broadcast nature of wireless communications means that one receiver can receive the superposition of multiple transmitted signals. But on the other hand, it means that multiple receivers can receive the same transmitted signal. The former leads to congestion and concerns about reliability because of the limited nature of the electromagnetic spectrum and the vulnerability to interference. The latter means that wirelessly transmitted information is inherently insecure. This thesis aims to provide insights and means for improving physical layer reliability and security of wireless communications by, in a sense, combining the two aspects above through simultaneous and same frequency transmit and receive operation. This is so as to ultimately increase the safety of environments where wireless devices function or where malicious wirelessly operated devices (e.g., remote-controlled drones) potentially raise safety concerns. Specifically, two closely related research directions are pursued. Firstly, taking advantage of in-band full-duplex (IBFD) radio technology to benefit the reliability and security of wireless communications in the form of multifunction IBFD radios. Secondly, extending the self-interference cancellation (SIC) capabilities of IBFD radios to multiradio platforms to take advantage of these same concepts on a wider scale. Within the first research direction, a theoretical analysis framework is developed and then used to comprehensively study the benefits and drawbacks of simultaneously combining signals detection and jamming on the same frequency within a single platform. Also, a practical prototype capable of such operation is implemented and its performance analyzed based on actual measurements. The theoretical and experimental analysis altogether give a concrete understanding of the quantitative benefits of simultaneous same-frequency operations over carrying out the operations in an alternating manner. Simultaneously detecting and jamming signals specifically is shown to somewhat increase the effective range of a smart jammer compared to intermittent detection and jamming, increasing its reliability. Within the second research direction, two interference mitigation methods are proposed that extend the SIC capabilities from single platform IBFD radios to those not physically connected. Such separation brings additional challenges in modeling the interference compared to the SIC problem, which the proposed methods address. These methods then allow multiple radios to intentionally generate and use interference for controlling access to the electromagnetic spectrum. Practical measurement results demonstrate that this effectively allows the use of cooperative jamming to prevent unauthorized nodes from processing any signals of interest, while authorized nodes can use interference mitigation to still access the same signals. This in turn provides security at the physical layer of wireless communications

GIS and Remote Sensing for Renewable Energy Assessment and Maps

This book aims at providing the state-of-the-art on all of the aforementioned tools in different energy applications and at different scales, i.e., urban, regional, national, and even continental for renewable scenarios planning and policy making

Satellite-Based Communications Security: A Survey of Threats, Solutions, and Research Challenges

Satellite-based Communication systems are gaining renewed momentum in Industry and Academia, thanks to innovative services introduced by leading tech companies and the promising impact they can deliver towards the global connectivity objective tackled by early 6G initiatives. On the one hand, the emergence of new manufacturing processes and radio technologies promises to reduce service costs while guaranteeing outstanding communication latency, available bandwidth, flexibility, and coverage range. On the other hand, cybersecurity techniques and solutions applied in SATCOM links should be updated to reflect the substantial advancements in attacker capabilities characterizing the last two decades. However, business urgency and opportunities are leading operators towards challenging system trade-offs, resulting in an increased attack surface and a general relaxation of the available security services. In this paper, we tackle the cited problems and present a comprehensive survey on the link-layer security threats, solutions, and challenges faced when deploying and operating SATCOM systems.Specifically, we classify the literature on security for SATCOM systems into two main branches, i.e., physical-layer security and cryptography schemes.Then, we further identify specific research domains for each of the identified branches, focusing on dedicated security issues, including, e.g., physical-layer confidentiality, anti-jamming schemes, anti-spoofing strategies, and quantum-based key distribution schemes. For each of the above domains, we highlight the most essential techniques, peculiarities, advantages, disadvantages, lessons learned, and future directions.Finally, we also identify emerging research topics whose additional investigation by Academia and Industry could further attract researchers and investors, ultimately unleashing the full potential behind ubiquitous satellite communications.Comment: 72 page