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Item type:Publication, Access status: with files , Designing problem-based learning cases to foster student engagement in STEMWe all recognize the effectiveness of problem-based learning (PBL) in engaging everyone and helping students develop critical thinking and teamwork skills. PBL was developed to make medicine students ready to work under real life conditions. Therefore, since the 50s there have been several cases for medicine scenarios being published. In the STEM field it is still not common to use this method, which is quite unfortunate. Therefore, we have chosen to share how we implement PBL to teach Communication Networks to master’s students. In this paper, we will present our experiences in designing new PBL cases, alongside feedback from our Center for Teaching and Learning (ZLL). These cases reflect current trends in key topics related to communication networks, our engagement strategies, and the student feedback we have received during the winter semester 2024/25.Publicationtype: Conference Paper48 43 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Characterizing Space Communication Channel Behavior: An Analytical Approach with ESA Mission Data Validation(2025-01-01); ; ; Quintanilla, JorgeSpace communication networks face unique challenges that distinguish them from terrestrial systems. As missions extend deeper into the Solar System Internet (SSI), effective Quality of Service (QoS) mechanisms become critical for managing scarce communication resources and ensuring mission success. This paper presents a comprehensive analysis of space communication channel characteristics through both analytical modeling and empirical validation using real mission data, thereby providing the necessary information to design a data-backed QoS framework for space. An analytical model is proposed, consisting of a three-state Markov chain that distinguishes between temporary signal degradation and extended outages due to space and atmospheric phenomena. The analysis of actual communication passes from ESA missions validates the theoretical predictions and identifies the contributors to communication failures. The empirical data also demonstrates the polarized nature of space communication performance, where passes either succeed with minimal losses or fail. These findings set the basis for the accurate channel and error modelling, which will allow for the future development of accurate and tailored QoS mechanisms that tackle the specific challenges of the communication environment.Publicationtype: Conference Paper79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Enabling traffic prioritization for space communications over DTNs(IEEE, 2024-06-17); ; ; The growing number of space missions planned in the near future has created a need for a robust communication infrastructure. Such an infrastructure is being developed in the frame of lunar communications by ESA moonlight and NASA lunanet using Delay-and Disruption-Tolerant Networking (DTN) and Bundle Protocol (BP). While their characteristics have made them the standard for future space communications, some areas such as Quality of Service (QoS) or quasi-real-time communications are still to be further developed. This study emphasizes the benefits of using traffic prioritization as a mechanism to enhance QoS and enable quasi-real-time communications between Earth and space. Through a three-state Markov Chain model, the specific channel between Earth and the Moon is modelled realistically, and the impact of traffic prioritization on bundle transmissions is analyzed for several types of transmitting sources. When looking at the amount of high-priority bundles arriving within the 2.5mark set by ESA for it to be considered quasi-real-time communications, it is shown that there is a significant improvement of up to 23%. This feature is crucial for DTN BP to be able to support the requirements of the upcoming lunar missions, especially those involving extended astronaut stays. Moreover, a priority grid taking into account all the current requirements expressed by both ESA and NASA is presented, as well as implementation proposals to include traffic prioritization in BP as an extension block. Lastly, the need for a common policy for all DTN nodes in order to allow interoperability is highlighted. Therefore, this work contributes to the advancement of DTN BP, bringing it closer to the requirements ahead of us, and paves the way for the needed mechanisms to be implemented.Publicationtype: Journal Article132 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Enabling quality of service over DTNs for space communicationsThe increasing importance of space exploration is marked by the dozens of upcoming missions, and it has highlighted the need for a common and robust communication infrastructure. However, space communications face unique challenges that are not present in terrestrial communications. To address these issues, Delay- and Disruption-Tolerant Networks (DTN) and the Bundle Protocol (BP) were introduced. While DTN and BP are a great starting point, further enhancements are required for reliability and quasi-real-time communications. This work proposes extending BP to communicate about and allow for the optimization of Quality of Service (QoS) parameters, including latency, data loss, and jitter, crucial for satisfying the various communication needs between Earth and space. These contributions aim to enable future space communication capabilities, and to support ambitious projects such as the Solar System Internet.Publicationtype: Conference Paper63 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Adding Quality of Service Support to Bundle Protocol Through an Extension BlockThe Bundle Protocol (BP) was designed to address the challenges inherent in space communications. While already in use in several projects led by various space agencies, including the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA), there is a need to expand BP's capabilities, including in Quality of Service (QoS) support, an area currently lacking standardization. This document proposes a dual QoS support block for BP which facilitates the definition of QoS requirements at the source in an immutable manner while allowing dynamic adjustments by networks or subnetworks. Furthermore, preliminary results are presented, analyzing the effects of the proposed traffic prioritization system and the weighted queue management. These results show improved end-To-end delay for time-sensitive information, and a higher rate of achieved QoS requirements for all priority classes, as well as a fairer approach to network scheduling.Publicationtype: Conference Paper19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Lunar communication services: Feasibility study on traffic prioritization of quasi-real time communications over DTNs(IEEE, 2023-09); ; ; As more missions aim to explore the Moon, the need for a robust communication infrastructure becomes apparent. Such infrastructure is currently being developed by the European Space Agency (ESA) using Delay and Disruption Tolerant Networks (DTN) with the Bundle Protocol (BP). Nevertheless, these networks are not currently equipped with the necessary means to provide quasi-real time communications over highly stressed communication links as the Earth-Moon one. This paper models this link using a three-state Markov Chain which incorporates realistic data, accounting for long-And short-Term losses. Using this model, the benefits of using traffic prioritization are assessed through the delay, and other performance-impacting metrics are analyzed, such as the average length of error bursts. This work proves that traffic prioritization reduces delays for data marked as high-priority, achieving delays below the 2.5s mark for 72% of bundles. Natural phenomena, like solar flares, demonstrate a limited impact on overall delay but shown a larger influence on burst losses, which would be significant for streaming-related applications. These results contribute to the understanding of how to transmit quasi-real time data over DTN BP and help pave the way to an efficient design of future communication systems for lunar missions.Publicationtype: Conference Paper64 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Machine learning-based dynamic spectrum access for aircraft-to-aircraft communication under coexistence with legacy radio systems(2022-06-30)Spectrum scarcity is viewed as one of the key obstacles in the area of wireless communications. The lack of available unlicensed resources is impairing the development of newer and more modern communications systems. This is the case of L-band Digital Aeronautical Communications System (LDACS), an innovative air communication system that aims to use the part of the frequency spectrum licensed by Distance Measuring Equipment (DME), a legacy radio navigation system. DME has a low channel utilization rate, leaving idle numerous resources that could be used by LDACS through the use of Dynamic Spectrum Access (DSA) in Cognitive Radio (CR). In order to avoid interferences and collisions while taking advantage of these idle resources, this thesis proposes a new LDACS Machine Learning (ML)-based Medium Access Control (MAC). It incorporates a Long Short Term Memory (LSTM) Recurrent Neural Network (RNN) in order to observe, learn, predict and avoid the DME licensed users. The results from this new MAC are analyzed and compared to two alternative approaches, showing the advantages of a ML-based approach.Publicationtype: Master Thesis106 302