Theses
UWE-5
Context
- The UWE-5 project shall use nanosatellites to relay traffic between the Würzburg and Cottbus ground stations
- 3GPP (the standards body responsible LTE, 5G, ...) has created a model of a satellite to user equipment (UE, the mobile device) channel - and while with UWE-5 no satellite-to-UE communication will be attempted, it still serves as an indicator for the future
Tasks
- Understand and implement the 3GPP channel model and a diversity scheme (e.g. Alamouti) in a simulation
- Evaluate the connection (e.g. coded BER or mutual information) with and without diversity - does it provide an improvement?
Supervision & Contact
Context
- Multiple competing Low Power Wide Area Network (LPWAN) standards exist, mainly designed for terrestrial IoT applications
Tasks
- Survey of existing standards and their design criteria (what was optimized for, trade-offs, ...)
- Which ones would be suitable for ISL and Space-Ground communications?
- How much of the standard can be used in a typical university CubeSat mission?
Supervision & Contact
Context
- UWE-5 will carry an Software Defined Radio (SDR) and some COTS transceivers, which will be up-and downconverted to and from K/Ka band+
- An SDR allows lots of flexibility, therefore many choices are available
- The COTS transceivers currently planned are the SX1280 (LoRa, FLRC and FSK)
Tasks
- Investigate different modulation schemes possible with the SDR
- Compare the SDR and COTS transceiver schemes in simulation or theoretically (data rate, bit error rate, energy requirements, ...)
Supervision & Contact
Context
- UWE-5 will carry and Software Defined Radio (SDR) and some COTS transceivers
- An SDR trades flexibility for energy efficiency
- Energy is always at a premium on satellites
Tasks
- Research energy-efficient digital signal processing programming techniques
- Compare different implementations (COTS, SDR with stock/own implementation, FPGA?)
Supervision & Contact
Context
- FSCM is the waveform also used by LoRa: The offset from a base chirp determines the symbol
Tasks
- Implement modulation and demodulation for SDRs with e.g. Julia - an "offline" (i.e. not live) approach is fine and allows gaining a thorough understanding of digital signal processing and practical low-level experience
- In Contrast with LoRa the "higher level" features of the PHY (interleaving, coding) can be left out, but whitening probably needs to be implemented
- Evaluation can e.g. be different methods for synchronization, compatibility of your demodulaor with ISL / Doppler shift, etc.
Supervision & Contact
- If you have own ideas, please reach out! We are open to ideas that are modifications of mentioned topics or ideas that are not explicitly listed here.
Satellite Networks for 6G and Beyond
Tasks
- Literature research on satellite networks for high coverage with a focus on 5G/6G solutions
- Feasibility study of connecting 5G campus network to UWE satellites or a satellite network in general
- Implementation of communications link between 5G campus network and a UWE satellite
- Comparison to alternative communication systems like, e.g., LoRa
Supervision & Contact
Tasks
- Problem Formulation: scheduling and resource allocation minimising transmit power in the downlink
- Optimisation and Evaluation of Power Savings
- Paper: “LEO-to-User Assignment and Resource Allocation for Uplink Transmit Power Minimization, Hung Nguyen-Kha, Vu Nguyen Ha, Eva Lagunas, Symeon Chatzinotas and Grotz Joel, WSA & SCC 2023”
Supervision & Contact
- Interference Management in Large LEO Satellite Constellation Networks
- Distributed Massive Multiple-Input Multiple-Output Satellite Communications
Quantum Communications
Context
- No real world quantum communications can be performed without errors
- Currently this is the most limiting fact for quantum communications but also for quantum computers in general
- Different quantum based strategies for error correction already exist
Tasks
- Define error models for typical errors of quantum computers (e.g. depolarization and dephasing channels)
- Investigate Shor code, Steane code and Laflamme code for these error models
- Comparison of these traditional codes with state-of-the-art codes
Supervision & Contact
Context
- Error correction codes are one of the fundamental building blocks missing for implementing highly scalable quantum architectures
Tasks
- Implementation of quantum Low Density Parity Check (LDPC) and quantum polar codes
- Implementation of different decoding algorithms [see, e.g., [Chandra2023](https://doi.org/10.1109/ACCESS.2023.3247966)]
- Simulation of an erroneous discrete-variable and/or continuous-variable quantum communications link using these codes for error correction
- Performance analysis
Supervision & Contact
Context
- Future interconnected quantum networks need to be routed
- Due to the fundamental different way of how quantum networks work, in contrast to classical networks, completely new routing mechanisms need to be investigated and implemented
Tasks
- Investigation of different routing strategies within quantum networks
- Modelling of entanglement distribution within quantum networks
- Construction of a quantum routing algorithm
- Simulation based evaluation of the routing algorithm
Supervision & Contact
Context
- Entangled quantum states is the core resource for most quantum communications applications
- But due to unavoidable implementation imperfections the quality of entangled states degrades within communications networks
- Entanglement distillation protocols offer a quantum procedure to distill many weakly entangled states into fewer, but higher entangled states
Tasks
- Modelling of different quantum networks and the disentanglement within
- Analysis of different entanglement distillation protocols within such networks
- Simulation and investigation of optimal distillation approaches
Supervision & Contact
Context
- Quantum repeaters are the key building block of quantum communications networks
- While theoretical descriptions for quantum repeaters of three different generations exist, their performance in realistic scenarios still has many open questions
Tasks
- Literature research on different quantum repeater architectures
- Building a simulation framework (preferably in Julia) to numerically simulate the performance of certain quantum repeater architectures
- Analyzing the influence of different parameters on the efficiency of quantum repeaters
Supervision & Contact
Context
- Even though quantum communications is what enables QKD, every protocol implementation still requires classical communications and classical post processing
- Especially in the context of the security of an QKD protocol these classical algorithms play an important role
Tasks
- Survey on schemes for classical post processing (Information reconciliation and privacy amplification)
- Implementation and simulation of selected algorithms
- Performance analysis and comparison of the simulated algorithms
Supervision & Contact
Context
- CV-QKD systems pose a promising alternative to DV systems, as they can be implemented using more of the shelf components
Tasks
- Combine CV-QKD with higher modulation schemes
- Performance analysis (risk and key rate)
- Comparison to state-of-the-art
Supervision & Contact
Context
- Quantum physics define the fundamental limit of mesurment precision
- Utilizing quantum effects like squeezed states allow higher precision than any classical system could ever achieve
Tasks
- Quantum sensing is based on squeezed light which decreases the measurement variance at some time instances
- For quantum sensing to work, this time instances need to be determined before sampling
- Development and investigation of a clock synchronisation algorithm for quantum sensing
Supervision & Contact
- Synchronisation of a quantum network
- Channel estimation and prediction of a dynamic optical satellite-to-ground link for the correction of polarization errors
- Comparison of discrete variable (DV) and continious variable (CV) systems for the application in satellite networks
Free-Space Optical Communications
Tasks
- Implementation of a free-space optical communications link based on Pulse-Position-Modulation (PPM)
- Realisation of an optical Drone-to-Ground communications link
- Realisation of an optical Drone-to-Drone communications link (if time)
- Performance analysis
Supervision & Contact
Tasks
- Basic paper: Jamali et al. (2021)
- Applications
- V2V communications
- drone network
- satellite network
- Simulation or experimental set-up
Supervision & Contact
Joint Communications and Sensing
Tasks
- Literature recherche on exisiting schemes (MOCZ and alternatives)
- Focus on the evaluation of the sensing capabilities
- Numerical analysis
Supervision & Contact
Tasks
- Reusing Lidar for communications (classical one- and two-way, e.g., car-to-car)
- Investigation of different modulation schemes
- Proof of concept and performance evaluation
Supervision & Contact
Tasks
- Investigation of two possible strategies:
- fixed beams and direction finding/tracking via attitude control
- fixed attitude and direction finding/tracking via beamforming (antenna array)
- Simulative performance evaluation
- Proof of concept based on the usage of drones
Supervision & Contact
- Acoustical Underwater Multiple-Input Multiple-Output Communications
- Joint Acoustical Underwater Communications and Sensing
- Distributed Massive Multiple-Input Multiple-Output Satellite Communications
Dynamic Wireless Meshed Networks
Tasks
- Simulation of received signal strength in multipath propagation environments with different frequencies
- Implementation of a distance estimation algorithm via a communication interface with integrated frequency hopping (e.g., Bluetooth)
- Evaluation and comparison of simulation results with experimentally measured data
Supervision & Contact
- Radio Based Localisation of Nodes in a Drone Swarm Network
- Decentralised Synchronisation of Nodes in a Drone Swarm Network
- Design of a LoRa Communication System with Adalm Pluto and Julia
Radar Signal Processing
Tasks
- Combination of difference and angle of arrival methods
- Phase synchronisation methods
- Numerical analysis
Supervision & Contact
- System Design of Joint Radar Sensing and Wireless Communication
- Design and Simulative Investigation of a MIMO-OFDM-Radar
Thesis LaTeX Template
A template and some hints for writing a good thesis are available on the IfI GitLab: https://gitlab2.informatik.uni-wuerzburg.de/scrs/templates/latex_thesis
