Research Projects
Quality-of-Service and Connected Mobility
(Own Funds)
Abstract:
Network calculus (NC) is a system theory for deterministic performanceevaluation. It uses mathematical methods to provide performanceguarantees for communication systems. It can be applied in thedesign phase of future systems as well as the analysis of existingsystems. In real-time systems, the timeliness of events plays animportant role. Therefore, the classical performance evaluation based onstochastic methods that result in (stochastic) expectation values, i.e.mean values, has to be extended by mathematical tools producingguaranteed bounds for worst case scenarios. Network calculus allows toobtain upper bounds for end-to-end delays for one nodes or aseries of nodes within a network, upper bounds for the required bufferspace and bounds for the output flow.These analytic performance bounds characterize the worst-case behaviorof traffic flows and allow dimensioning the corresponding systems.Currently, we study the applicability of NC for multiplexed flows, inparticular when the FIFO property cannot be assumed at the merging ofindividual flows. The aggregation of data flows plays an important rolein modelling the multiplexing scheme. We apply NC for performanceevaluation both of aggregate multiplexing at one node and atconcatenation of aggregated multiple nodes in different scenarios.
We have successfully introduced network calculus methods in thefield of internal automotive communication systems in industrialapplications. Embedded in-car networks need to fulfill hardreal-time constraints. While TDMA-based access schemes in FlexRayguarantee that certain bound can be met, statistical multiplexingin CAN networks only allows to calculate bounds for the highestpriority messages. By applying network calculus, we obtained boundsfor all priority classes without the need to specify a concretescheduling of the messages. Upper bounds for the amount of datathat arrives at each network node are enough to determine hardbounds for the end-to-end delay in CAN networks.Another field of application is industrial communication.Factory automation often also requires hard real-time boundsfor the end-to-end delay of messages. The use of Ethernet withpriority tagging allows cost-efficient implementation offactory automation systems. But without stringent planningof the network, the required bounds on the end-to-end delaycannot be guaranteed. Network calculus allows to obtain therequired bounds when applied in the planning phase of thenetwork. It also allows to dimension the buffers of nodes,e.g. of industrial Ethernet switches. Nowadays, some ofthe users of industrial Ethernet need to integratenon-real-time products like web cams and remote operationterminals into existing networks. Withoutadditional analysis, the additional traffic caused by devicesthat do not require hard real-time constraints willcause a violation of the bounds for the delay and bufferspace for real-time traffic. By taking into account thisnon-real-time traffic in network calculus and by applyingtraffic shaping for the non-real-time flows allows todimension the network so that all bounds are met.Network calculus is currently integrated into an existingautomated industrial network planning tool.
TSN-Logo
(Own Funds)
Abstract:
This research project deals with the application of quality of service guarantees in Time-Sensitive Networking, in particular using Network Calculus. Real-time systems are increasingly required in industry, e.g. the automotive, automation or entertainment industries. Classical Ethernet, however, does not guarantee real-time performance, which leads the Time-Sensitive Networking Task Group (IEEE 802.1) to develop standards for real-time data transmission over Ethernet networks. These standards are summarized under the term Time-Sensitive Networking (TSN). Within the scope of this research project, the application of Network Calculus for TSN is now being investigated. Network Calculus (NC) is a system theory for deterministic performance evaluation. It uses mathematical methods to provide performance guarantees for communication systems. NC can help evaluate TSN's real-time properties, meet required latency limits, and provide insight into the optimal configuration of networks. It also enables buffer sizing and can evaluate existing or new scheduling algorithms.
(Third Party Funds Single)
Abstract:
As part of a large consortium, the Chair of Computer Science 7 is involved in the project with the model-based system design of the vehicle communication systems under inclusion of variant diversity. For this purpose, on the one hand, an optimization for the configuration and resource design of the network architecture for different communication protocols and mechanisms is realized. On the other hand, safety analyses are performed using fault trees and extending them for product lines.
Network calculus is used for the formal verification of the required real-time properties. Therefore, suitable approaches for the scheduling methods applied in the networking technologies (e.g. TAS, priority-based, CBS, etc.) have to be formulated.
Model and code generators will be developed for automated and accelerated generation of the network optimizations. safety and real-time analyses. The results of these analyses are fed back into the modeling of the overall system.
(Third Party Funds Single)
Abstract:
In transmission systems, a dedicated and high-performance communication infrastructure allows a parallel execution of communication-intensive functions and services. In the course of the expansion of renewable energies at lower voltage levels of the distribution networks and the shift of system responsibility to (operators of) these plants and systems, similar functions and services must also be implemented at the distribution network level in Smart Grids – so-called Smart Grid Services (SGSs).
In this project, we will therefore conduct research on online reconfiguration methods based on a two-step QoS-provisioning approach: At a first level, discrete optimization is used to find an allocation of SGSs to available servers and allocation of flows to paths through the communication network based on a topological view of the compute, storage, and communication facilities. At a second level, Network Calculus is used to ensure analytically that all critical SGSs can meet their QoS requirements. The overall effect of the two-step approach will then be assessed by simulation.
FAU will be mainly considering the networking and QoS aspects in this cooperation, while Oldenburg University will concentrate on the effects on the energy network and the reconfiguration of the Smart Grid Services.
(Third Party Funds Single)
Abstract:
In the QUICSAT project, the cooperation between the Friedrich-Alexander University (FAU) Erlangen-Nürnberg and ND SatCom GmbH has the common goal of improving Internet protocols and applications for geostationary satellite connections.
The potential of new technologies (AQM, ECN, BBR and especially QUIC) will be examined. The ultimate goal is that Internet via satellite should perform as good as terrestrial Internet connections.
The high latency of geostationary satellites, the current architecture of Internet protocols and the constantly increasing complexity of Internet applications (especially websites) are the reason why the performance of Internet via satellite is sometimes worse than the performance of terrestrial Internet connections, even if the data rates are comparable. Newer Quality of Service (QoS) mechanisms are currently not used in satellite communication. With QUIC there is also the risk that the performance of satellite internet will decrease due to the non-applicability of Performance Enhancing Proxies.
The project makes a contribution to protocol research, standardization and reference implementations.
External Partners:
- ND SatCom GmbH
(Third Party Funds Single)
Abstract:
The TCP performance over satellite communications has become a well-known problem, following significant experimentation with Internet services over satellite since the '90s. Several tailored TCP optimisations have been introduced (mainly implementing changes at the sender side, but also at the receiver side in some proposals). In parallel, given the challenge of installing tailored TCP versions directly in the end user system, a set of architectural extensions have been introduced culminating in the concept of a Performance Enhancing Proxy (PEP, RFC 3135), whereby a native end-to-end TCP connection is now commonly split into a series of multiple connection (a split TCP concept). This allows a tailored TCP to be deployed on the satellite link (i.e., between the satellite terminals and gateways to be optimised). Though largely used since the early 2000's, PEPs have always been unable to enhance non-TCP protocols or VPN connections traversing the satellite network segment. Application-layer compression and acceleration was also provided in some PEPs.
Since 2000, there has been a continued effort to evolve the protocol stack for Internet web services, with several updates to the protocols for HTTP-based services. A design of HTTP by Google, known as SDPY, was standardised as HTTP/2. This provided significant improvements in download speed of satellite, but at the same time deployed application-layer encryption and compression – making application-layer acceleration dependent on using an authenticated proxy and impossible within a PEP.
A more recent Google proposal (known as gQUIC) sought a transport other than TCP that uses a UDP substrate with transport encryption. This effort evolved in standardisation by the Internet Engineering Task Force (IETF) and was finally published as IETF QUIC (RFC 9000) in 2021. QUIC is specified for use with HTTP/3, a replacement for HTTP2/TCP. The main leap from classical HTTP services over TCP is in that QUIC uses encrypted datagram connections, with congestion control, flow control, NAT-rebinding and migration algorithms directly implemented within the QUIC protocol. Following standardisation, QUIC and HTTP/3 have been implemented and have been rapidly deployed to the Internet.
Hence, the design rationale of QUIC intrinsically prevents using a classical PEP solution for the optimisation of performance over a satellite system. Whilst the application-layer performance of HTTP/3 resembles or improves on that of HTTP/2, and the transport design has been shown to operate correctly over satellite with respect to initialisation, protocol timers, and other core functions, experiments have shown that performance of QUIC operated end-to-end over paths comprising a satellite network segment can be lower than offered by TCP using a PEP. This has motivated the scientific community and the satellite industry to think of alternative solutions for QUIC congestion control (CC) to accelerate with the QUIC performance degradation, which is still now at the early stages. QUIC has also been suggested for other applications.
The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt), University of Aberdeen, and Friedrich-Alexander-Universität Erlangen-Nürnberg have built a consortium that is committed to thoroughly analyse the existing approaches and options to improve the performance of TCP over satellite network segment and apply the most appropriate concepts to QUIC congestion control mechanisms as well as understanding the implications of deploying the new approaches as a part of a secure end-to-end architecture. As a result, a novel algorithm will be defined and then verified against the relevant technical requirements. Finally, the resulting new QUIC specifications will be validated using real satellite trials in exemplar scenarios.
External Partners:
- Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center
- University of Aberdeen
5G-AUTOSAT_KI Logo
(Third Party Funds Group – Sub project)
Abstract:
The cooperation between Airbus Defense and Space GmbH, Fraunhofer Institute for Integrated Circuits, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg and ZF Friedrichshafen AG has the common goal of increasing the connectivity for automotive applications in hybrid satellite-terrestrial 5G networks using artificial intelligence.
The FAU works primarily on concepts for the integration of automotive applications, the creation of a simulation model for the combination of vehicular and satellite communication, the integration of AI algorithms, the performance evaluation and optimization of quality-of-service related protocols, and supporting the implementation of a real-time demonstrator. Results shall be presented at scientific conferences and contribute to the standardization of 5G and future 6G networks.
External Partners:
- Fraunhofer-Institut für Integrierte Schaltungen (IIS)
- Airbus Defence and Space GmbH
- ZF Friedrichshafen AG
(Non-FAU Project)
External Partners:
- Zukunft Mobility GmbH (a company of ZF Group)
(Third Party Funds Single)
Abstract:
Satellite communication is a way to provide broadband internet access all over the world. However, with geostationary satellites the propagation delay leads to very high delays in the magnitude of several hundred milliseconds. In order to improve the interactivity and responsiveness of communication systems, utilizing a second communication link can be highly beneficial.
The Transparent Multichannel IPv6 (TMC-IPv6) Project aims to combine the advantages of multiple heterogeneous communication links. An illustrative example is the combination of a rural DSL connection with low data rate/low latency and a satellite connection with high data rate but high latency, which results in a users internet access with high data rate and low latency providing a better Quality of Experience (QoE).
Satellite-based internet access from different operators is provided by our project partners in order to experience realistic satellite communication environment and test potential solutions. The outdoor unit (parabolic antenna) is mounted on the roof of the Wolfgang-Händler-Hochhaus.
(Non-FAU Project)
Abstract:
This work evaluates the performance of different applications over different Internet access technologies, with focus on Internet access via satellite.
The following Internet access technologies have been selected:
- Geostationary satellites (Konnect/Eutelsat, skyDSL/Eutelsat, Bigblu/Eutelsat, Novostream/Astra Connect)
- Satellite megaconstellations in low Earth orbit (Starlink)
- Terrestrial systems as reference (o2 DSL, Congstar LTE)
External Partners:
- European Space Agency (ESA), Netherlands
- Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center
(Own Funds)
Abstract:
The electrical energy network is in a state of change due to the digitization and integration of decentralized energy sources. Pervasive and interconnected sensors and actuators are creating complex virtual control systems.
Based on an efficient communication network, innovative services and applications can provide an ecological, economical, stable and high-quality energy supply. A particular challenge are the diverse requirements and traffic patterns of applications that may be distributed over large areas and time critical.
The object of this research project is the replacement of proprietary solutions by a programmable communication network with standard components. These enable economical operation and high compatibility, individual requirements are fulfilled by software. The overarching goal is to make optimal use of the infrastructure of the energy and communication networks and to minimize over-provisioning.
Connected Mobility until July 2025
(Own Funds)
Abstract:
(Own Funds)
Abstract:
Simulation is a decent method to study, evaluate, and validate upcoming technologies and algorithms. In order to generate realistic results, it is necessary to overcome different challenges. One of these challenges is the computational feasibility of holistic simulation scenarios, especially when it comes to large-scale setups. These scenarios may model a whole city or even an entire country. Besides performance problems, adequate modeling of real world scenarios often requires the combination of multiple simulation tools from different domains. This combination often requires the connection of different modeling paradigms. Other challenges tasks are the time synchronization of the different simulation tools and the data exchange between them.
To solve these problems, a hybrid co-simulation framework is developed in this project. The Framework uses an implementation of High Level Architecture (HLA, IEEE1516) as a middleware and enables the dynamic composition of a simulation setup that matches current requirements. The composition takes place in two dimensions. In a vertical dimension, multi-level support empowers the simulation at different levels of detail, corresponding to the demands regarding performance, available data, or posed questions. In a horizontal dimension, the coupling of tools from different domains is enabled. The focus on extendability makes it possible to add any needed tools at a later point in time to the framework.
(Non-FAU Project)
Abstract:
Die Funktionssicherheit von Fahrerassistenzsystemen sowie automatisierter und vernetzter Funktionen ist vom Automobilhersteller in jeder denkbaren Verkehrssituation sicherzustellen. Im Entwicklungs- und Absicherungsprozess ist dazu eine erhebliche Zahl von Verkehrssituationen, sog. Szenarien, abzuprüfen. Dieser umfangreiche Prüfumfang lässt sich in Zukunft nur noch durch den massiven Einsatz von Computersimulation sinnvoll bewältigen. Um in diesen Simulationen eine entsprechende Validität und Praxisrelevanz zu erzeugen, müssen Modelle des eigenen Fahrzeugs, der Strecken und –Umgebung sowie des umgebenden Verkehrs adäquat modelliert werden.
Im Rahmen dieser Arbeit soll eine Methodik zur Absicherung von Systemen und Funktionen des automatisierten und vernetzten Fahrens mittels Computersimulation auf virtuellen Streckenmodellen konzipiert und prototypisch entwickelt werden. Aspekte, die dabei Berücksichtigung finden sollen, sind Qualitätsanforderungen an das Streckenmodell hinsichtlich unterschiedlicher Sensor- und Reglerfunktionen, erforderliche Parameter/Dimensionen für die darzustellenden (Verkehrs-)Szenarien, Klassifizierung der Ähnlichkeit/Genauigkeit von digitalen Zwillingen (Simulation und Versuchsfahrzeug) oder auch eine Validierungssystematik für solch ein virtuelles Umfeldmodell.
Aufbauend auf die Anforderungen an die Simulation und den Spezifikationen an das virtuelle Streckenmodell soll ein systematisches und belastbares Verfahren zur simulationsbasierten Absicherung von automatisierten Fahrfunktion erarbeitet werden.
External Partners:
- Audi AG
(Third Party Funds Single)
Abstract:
Modern driver assistance systems for self-driving cars often rely on data collected by different sensors to determine the necessary system decisions. To prevent system failures, different techniques can be used to enhance the reliability of such multi-sensor systems, e.g., aggregation, filtering, majority voting and other mechanisms for fault tolerance. As a consequence, erroneous sensing is rare but can be correlated in successive sensor readings (e.g., as error bursts) and also between sensors (e.g., in specific environmental conditions such as bad weather).
For a reliable design, error probabilities of such multi-sensor systems must be determined. In the project an existing analytical model based on Markov chain as well as a simulation model should be extended. This includes the following aspects: extensions for several correlated sensors, integration of practically relevant sensor fusion algorithms, consideration of environmental conditions, adaption of structure and parametrization of the error model, extensions of the simulation for rare events and inclusion of code, validation of the model results based on available data, and realization as a software tool for the reliability design of multi-sensor systems.
In this project, the preliminary work of the INI.FAU project is to be built and both the existing analytical model based on Markov chains and the simulation model for multi-sensor systems are to be expanded. The desired scientific knowledge consists in the further development of the analytical Markov model, which already takes into account bursts of errors of individual sensors and dependencies between two sensors, the expansion to more sensors, the consideration of further error prevention strategies and a tool implementation. Furthermore, knowledge of the use of rare event simulation is to be achieved in order to execute more detailed simulation models of multi-sensor systems in practical terms and thus to derive statistically reliable results. The simulation allows an even more realistic system simulation and a validation of the analytical modeling. A scientifically based methodology is developed to determine the reliability of multi-sensor systems.
(Third Party Funds Single)
Abstract:
Vehicles are evolving to a mobile data platform. Besides mobility as their main purpose, the demand for entertainment, connectivity and current software is increasing. Besides installing updates in the workshop there is already today a mobile communication module built into the car, by which map updates, traffic information and entertainment applications are run. Mobile communication however depends on existing network coverage and can be limited in certain areas. Additionally a fee has to be paid to the mobile network provider, which is usually dependent on the amount of used data traffic. In this project additional technologies are to be evaluated, that may enable effective communication in the future. Publicly available WLAN hotspots have a potential as they are often available in the road area and can mostly be used cost-effective. Additionally vehicles need similar information, for instance a map update, that has to be delivered to multiple cars in the field. Therefor direct communication between vehicles as in 5G offers the possibility to exchange information in the field and reduce the usage of mobile communication. The goal is to test the combination of different technologies to a complex, heterogeneous vehicle network and evaluate the applicability of opportunistic networks. At the same time, proposals for future standardization are to be developed. From a scientific point of view suitable coordination and routing mechanisms are vital as connection times are short, vehicles serve as temporary storage and source of information and effective usage of transmission paths is relevant.
(Non-FAU Project)
External Partners:
- Audi AG
(Non-FAU Project)
Abstract:
External Partners:
- Fraunhofer-Institut für Integrierte Schaltungen (IIS)
(Own Funds)
Abstract:
The networking of vehicles with other road users or the infrastructure (Vehicle-to-Everything (V2X)) is one of the key technologies for autonomous driving and smart cities. The WLAN standard IEEE 802.11p developed for this purpose has already been the focus of research for a decade. So far, however, this communication technology has not been able to establish itself as a communication standard in the automotive industry. One possible reason for this is the non-existent stationary infrastructure (base stations at the roadside or at traffic lights), which would require high investments.
Many automobile manufacturers are therefore focusing their research on the latest generation of mobile radio technologies. The required infrastructure is available nationwide due to other mobile phone subscribers. LTE has already adopted specifications for direct communication between vehicles and communication via a base station. The latest mobile radio generation (5G), which is to be introduced from 2020, takes into account application cases and criteria for V2X communication right from the start. For 5G, the virtualization of mobile radio components via network slicing in conjunction with SDN and NFV will play a decisive role in maintaining quality of service parameters compared to LTE and WLAN.
For the simulation of V2X communication scenarios via WLAN IEEE 802.11p the Veins framework developed at the chair has been used in numerous studies. In order to evaluate comparisons between WLAN and mobile radio by simulation, a further development of Veins with the mobile radio technologies LTE/5G is of great interest. The focus here is in particular on questions of Quality of Service (QoS) and the planned V2X application cases. In the context of this doctoral thesis the Veins framework is extended to the 5G technology. The focus here is on mechanisms of the lower network layers and the planned network slicing and Quality of Service (QoS) approaches.
Logo
(Third Party Funds Group – Sub project)
Abstract:
The increasing networking and digitalization in the mobility industry leads to ever more complex systems and large amounts of data. This offers opportunities and challenges and requires innovative methods for research, analysis, development and validation of new mobility technologies. ViM aims to develop a platform prototype for research purposes and for the development of innovative business services, which can serve for testing novel mobility services and novel driving functions on a technical level (e.g. collaborative driving maneuvers). The aim is to develop a data and software framework that enables the introduction and use of different digital and modular components on the basis of their application context and provides mobility data as a basis for research, services and applications, taking into account any proprietary components. In particular, the platform allows the combination of real and simulated data to generate a realistic virtual world. Data analysis modules supplement this image and help to evaluate and interpret it.
The Chair of Computer Networks and Communication Systems is involved in all work packages and leads in particular the work package Simulation.
External Partners:
- BMW AG - Bayerische Motoren Werke / BMW Group
- Universität der Bundeswehr München
- Technische Universität München (TUM)
(Third Party Funds Single)
Abstract:
Distributed simulations are often used to improve performance or to couple different simulators. This coupling is very important for the simulation of autonomous driving functions, because reusable simulation components can be created for the closer and wider environment of the vehicle, for the ego and other vehicles, for sensor technology, for procedures in the control units, for vehicle dynamics and for similar aspects and can be executed together in a simulation. Furthermore, such a distributed simulation provides a starting point for coupling with real software or hardware components (SIL or HIL). Time management in the distributed simulation must ensure causality: if there are deviations in the assignment of simulation time to real-time in the components, causality violations can occur. One example is cooperative safety functions, where actions take place in a very fast sequence. Reasons for causality violations can be, for example, non-synchronized clocks or delays in message delivery. Another task of the time management is to ensure the reproducibility of the simulation results. Jitter in the execution time of individual components or during message transmission results in a non-determinism in the execution sequence, which can lead to a different simulation result.
(Non-FAU Project)
Abstract:
Die Funktionssicherheit von Fahrerassistenzsystemen sowie automatisierter und vernetzter Funktionen ist vom Automobilhersteller in jeder denkbaren Verkehrssituation sicherzustellen. Im Entwicklungs- und Absicherungsprozess ist dazu eine erhebliche Zahl von Verkehrssituationen, sog. Szenarien, abzuprüfen. Dieser umfangreiche Prüfumfang lässt sich in Zukunft eigentlich nur noch durch den massiven Einsatz von Computersimulation sinnvoll bewältigen. Um in diesen Simulationen eine entsprechende Validität und Praxisrelevanz zu erzeugen, müssen Modelle des eigenen Fahrzeugs, der Strecken und –Umgebung sowie des umgebenden Verkehrs adäquat modelliert werden.
Im Rahmen dieser Arbeit sollen Fahrsituationen, sogenannte Fahrszenarien, realer Versuchsfahrzeuge sensorisch erfasst und aufgezeichnet werden. Aus diesen Datenaufzeichnungen soll das aufgezeichnete Fahrszenario in einer Fahrsimulation nachgebildet und eine aktivierte automatisierte Fahrfunktion darin betrieben werden. Dadurch kann die Exaktheit des Simulationsmodells mit den aufgezeichneten Messdaten verglichen und validiert werden. Darüber hinaus werden so anspruchsvolle Fahrszenarien für einen Prüfkatalog gesammelt und das Fahrszenario kann mit vielen Variationen der zu simulierenden automatischen Fahrfunktion durchgespielt und verglichen werden.
Aufbauend auf einem funktionierendem Verfahren der Szenariengenerierung aus Messdaten soll ein Verfahren für gezielte Datenanalyse relevanter Szenarien aus Massendaten hinsichtlich Kategorien, Definitionen, Trajektorien zur Erzeugung von parametrierbarer Manöverklassen systematisch erarbeitet werden.