Offered Theses

Please contact the doctoral researchers directly if you are interested in a Bachelor or Master thesis, a student job, an "Ingenieurspraxis" or a "Forschungspraxis". It is also usually possible to find a topic that matches your specific interests. Each doctoral researcher's research topics and contact details are available on the personal websites.

Please include a curriculum vitae together with a list of attended courses when applying for a thesis.

If your "Ingenieurspraxis" is selected to be supervised by one of our professors, please hand in the documents to Doris Dorn (Room N2401).

Master's Theses

List decoding for multivariate polynomial codes

Description

Multivariate polynomials have been attracting increasing interest in constructing codes with repair capabilities by accessing only a small amount of available symbols, which is required to build failure-resistant distributed storage systems.

List decoding is a technique to decode beyond half the minimum distance and has shown its advantages for codes based on univariate polynomials.

In this thesis, the student is expected to learn from the literature about the list decoding algorithm for multivariate polynomial codes and develop new decoding techniques upon it.

Supervisor:

Automatic Bias Control for Optical IQ Modulation in Quantum Communications

Description

For our Advanced Technology team in Munich/Martinsried, we are looking for a motivated master thesis student at the intersection of optical (quantum) communications, electrical engineering, and cyber security. With the advancement of the continuous variable QKD (CV-QKD), information can be encoded on the quadratures of the incident electromagnetic field, like in commercial optical communication systems. This allows the information on coherent states of light to be captured at the receiver. Similar to coherent optical communications, Inphase & Quadrature (IQ) modulation is a crucial step for the generation of the QKD transmit signal . For this step the modulator, usually a Mach-Zehnder modulator (MZM), imprints the electrical baseband DAC output onto the continuous wave laser light.

Throughout this thesis work, the student’s main task will be to research, analyze and implement a practical IQ modulator for QKD applications.

Contact

utku.akin@advasecurity.com

Supervisor:

Utku Akin - Utku Akin (Adva Network Security GmbH)

Nonlinear Effects in Multi-Core Fibers

Keywords:
nonlinearity, optical communications, mcf, multicore fibers

Description

Space-division multiplexing (SDM), which consists in exploiting multimode fibers (MMFs) or multicore fibers (MCFs) instead of single mode ones, is one of the future optical communications architectures to increase data rates and network planning flexibility. The nonlinear properties of MCFs are of primary interest in assessing the usefulness of SDM against the current network. With this thesis, the student has the chance to work on a state-of-the-art topic in the field of optical communication systems, and progress quickly thanks to a tight (if desired) supervision. Would you be curious to know more about it? If so, just get in touch with me at paolo.carniello@tum.de (personal page https://www.ce.cit.tum.de/lnt/mitarbeiter/doktoranden/carniello/).

Prerequisites

-some knowledge on optical communications systems (e.g., Optical Communication Systems or Simulation of Optical Communication Systems Lab)

-some knowledge about communications engineering topics

Contact

paolo.carniello@tum.de
See https://www.ce.cit.tum.de/lnt/mitarbeiter/doktoranden/carniello/ for more info on the supervisor.

Supervisor:

Error Resilience in the Number-Theoretic Transform – PQC acceleration for safetycritical applications

Keywords:
post-quantum cryptography, HW acceleration, number theoretic transform

Description

Asymmetric cryptography is a core component of modern communication infrastructure. The existence of a sufficiently large quantum computer threatens all algorithms currently in use and recent developments in this field motivate the field of post-quantum cryptography (PQC), with the primary objective of developing secure and futureproof alternatives. To consolidate these efforts, the National Institute of Standards and Technology (NIST) is conducting a competition with the goal of selecting and standardizing the best available candidates.

In July 2022 four algorithms were selected, one Public-key Encryption and Key-establishment Algorithms (KEM) and three Digital Signature Algorithms (DSA). Of these four algorithms, three (including the two recommended for general purpose applications) are from the class of lattice-based schemes, i.e., they rely on difficult problems over lattices for their security.

The lattices in these schemes are represented by elements from a polynomial ring and arithmetic over this ring therefore plays a crucial role in their execution. To accelerate this arithmetic and, specifically, the multiplication of polynomials, the number-theoretic transform (NTT) is used. This approach is a generalization of the multiplication algorithms based on the fast Fourier transform (FFT), that have been long established in fields like signal processing. Since a considerable part of the computational complexity of these algorithms lies in this NTT, it is a prime candidate for HW acceleration and many works in literature have proposed such accelerators.

While considerable efforts have been made to offer fast and lean NTT accelerators, the topic of fault resilience has received little attention so far. In safety critical applications, as common in automotive or industrial fields, this resilience is an important feature and needs to be provided by the HW. On the other hand, these fields are traditionally price sensitive, so the additional chip area required for these features should be minimal. However, current approaches, such as those introduced by Sarker et al. [1], impose a large area (or latency) overhead.

The goal of this thesis is to address this shortcoming. First, the approaches published in literature shall be evaluated with regard to the relevant performance figures (area overhead, latency, …). Then, new approaches for error resilience in NTT calculation shall be developed, either based on improving upon existing methods or by adapting methods for error resilience in the computation of FFTs.

References

[1] Sarker, Ausmita, Alvaro Cintas Canto, Mehran Mozaffari Kermani, and Reza Azarderakhsh. “Error Detection Architectures for Hardware/Software Co-Design Approaches of Number-Theoretic Transform.” IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2022, 1–1. https://doi.org/10.1109/TCAD.2022.3218614.

Prerequisites

Basic understanding of HW design

Good knowledge of algebra

Contact

georg.maringer@tum.de

 

Supervisor:

Georg Maringer - Lukas Holzbaur, Alexander Zeh (Infineon Technologies)

Error correction for DNA storage

Description

DNA-based data storage is a novel approach for long term digital data archiving.

Due to the unique nature of writing and reading DNA, the channel associated with these processes is still relatively poorly understood and varies over different synthesis (writing) and sequencing (reading) technologies. The task of the student is to evaluate various decoding strategies for certain error-correcting schemes tailored for the DNA storage channel.

 

Prerequisites

- Basic principles of stochastic and algebra
- Channel Coding
- Information Theory

Supervisor:

Anisha Banerjee

[quantum] Quantum Machine Learning for Communication

Keywords:
physical, layer, quantum, machine learning, non-linear

Description

As part of an ongoing project with Huawei we are looking into quantum machine learning algorithms applied to decoding at the end of an optical fiber in the non-linear regime.

So far we have tried only the quantum version of k-mean clustering, however the goal is to test further quantum algorithms, in particular quantum support vector machines next, and their classical quantum-inspired counterpart.

The projects will involve reading the literature on quantum machine learning algorithms and quantum-inspired algorithms, find or come up with an implementation (this will involve the use of quantum libraries, in particular so far we have use qiskit), and benchmark the performance.

Prerequisites

Knowledge of quantum mechanics or quantum information is highly recommended.

Supervisor:

[identification] Applications of Identification Codes in V2X Communications

Keywords:
sumo, ns3, ns-3, vehicular, communication, identification, c++, Reed-Muller

Description

As part of the NewCom Project, new communication paradigms are investigated from an experimental perspective in order to construct proof-of-concept implementations that demonstrate the theoretical results obtained for Post-Shannon Communication schemes. In particular, this MSc thesis focuses on Identification Codes and their integration into a simulation environment where vehicular networks are modelled.

For this, the master student will first conduct a review of the state-of-the-art use cases for identification in the scientific literature and in form of patents, with an emphasis on V2X communications. By using an open-source V2X implementation based on LDR’s Simulation of Urban Mobility (SUMO) framework integrated with ns-3’s implementation of the ITS-G5 and LTE standards and conducting simulation in specific scenarios, the student will gain a first impression of the performance of the system using traditional transmission schemes. The integration of existing implementation of identification codes culminates this thesis, where KPIs will be defined in order to compare the advantages of using identification instead of transmission in the context of V2X communications.

Details about the C++ tools/libraries

The software used for the simulation of the vehicular network communication is ezCar2x

which build on and integrates the NS-3 (network simulation) and SUMO (traffic simulation) libraries

For the identification part and identification code based on Reed-Muller codes needs to be reimplemented (work in progress) from Python into C++ using the Givaro library

 

 

Prerequisites

  • Knowledge of communications engineering, mobile communications, wireless channel models, signal processing, and channel coding techniques (experience in LTE/5G cellular networks is a plus)

  • Interest in novel communication concepts as well in their practical implementation

  • Software experience: MATLAB, C++ and Python (experience with ns-3 or SUMO is a plus)

  • Comfortable working with Linux operative systems and distributed version control tools (e.g., gitlab)

  • Goal-oriented and structured work style

 

Contact

To apply, Please send your application by e-mail to Roberto Ferrara (roberto.ferrara@tum.de) and Luis Torres-Figueroa (luis.torres.figueroa@tum.de) with the following documents:

  • Curriculum vitae

  • Academic transcript

  • Short motivation (0.5 – 1 page)

Supervisor:

[identification] Simulation and performance improvement of identification codes

Description

Identification is a communication scheme that allows rate doubly exponential in the blocklemght, with the tradeoff that identities cannot be decoded (as messages do) but can only be verified.

The double exponential growth presents various challenges in the finite regime: there are heavy computational costs introduced at the encoder and decoder and heavy trade-offs between the error and the codes sizes.

The ultimate goal is to find a fast, reliable implementation while still achieving large code sizes.

Identification codes can be achieved by first removing the errors from the channel with regular transmission channel coding, and then sending a challenge though the corrected channel. For every identity i, The channenge is generated by picking a random input m and computing the corresponding output T_i(m) using a function T_i that depends on the identity. The challenge is then the pair m,T_i(m) and the receiver wanting to verify an identity j will verify whether j=i by testing the challenge. This is done by recomputing the output with T_j and verifying whether T_j(m)= T_i(m). The errors are reduced by ensuring that the various functions collide on a small fraction of the possible inputs.

It turns out that choosing good sets of funtions {T_i} is the same as choosing error-correction codes {c_i} with large distance, where now each codeword c_i defines a function by mapping positions m (sometimes called code locators) to symbols c_im of the codeword.
We can thus construct identification codes by choosing error-correction codes where we are only interested in the performance of the error correction encoders (we are not interested in the error-correction decoder or error-correction codes).

Your task will be speeding up the current implementations based on Reed-Solomon and Reed-Muller codes:

The coding will be in Python/Sagemath.
This work can accomodate multiple students.
The working language will be in English.

Environment: we collaborate with LTI. At LNT and LTI there is currently a lot of funding for research in identification. Therefore you will find a large group of people that might be available for discussion and collaboration.

Prerequisites

Nachrichtentechnik 2

 

Supervisor:

[security] Practical implementation of physical-layer semantic security

Keywords:
semantic, security, secrecy, programming, implementation

Description

The goal of this project is to implement in Python/Sagemath the security functions (at least one of four) described in https://arxiv.org/abs/2102.00983
Sagemath contains libraries for mosaics, BIBDs, etc, that can be used for the project.

Motivation:
There are various types of security definitions.
The mutual information based types, in increasing order of security requirement are

  1. Weak secresy asks that the average mutual information of the eavesdropper I(M:E)/n goes to 0 for a uniform message M (average here means averaged over the blocklength n, an additional average over M is implicit in the mutual information)
  2. Strong secrecy asks that the total mutual information I(M:E) goes to 0,
  3. Semantic security asks that the total mutual informaiton I(M:E) goes to 0 for any distribution of the message M (and thus in particular for all distributions that pick any of two chosen messages with 1/2 probabilty)

Then there are the almost-equivalent respective indistiguishablity types  of security requirements (below |P-Q|_1 is the statistical distance and Exp_M is expectation value over M)

  1. average indistinguishability 1/n Exp_M | P_{E|M} - P_E |_1 for a uniform message M goes to 0 (again average refers over the blocklegth n, clearly there is also the average over M)
  2. total indistiguishability Exp_M | P_{E|M} - P_E |_1 for a uniform message M goes to 0
  3. indistinguishability |P_{E|m} - P_{E|m'}|_1 for any two messages m and m' goes to 0.

Each of the indistiguishabilities can also be written using KL digvergence instead of statistical distance, in which case the conditions are exactly equivalent to their mutual information versions.

Strong secrecy is the standard security requirement considered in information-theoretic security, while semantic security is the minimum requirement considered in computational security.
Information-theoretic (physical-layer) security differs from computational security in that the secrecy is guaranteed irrespective of the power of the adversary, while in computational security E is computationally bounded. Computational security also assumes that the message is at least of a certain length for the schemes to work, and thus if the message to be secured is too small it needs to be padded to a larger message.

In practice, information theoretic security is expensive, because the messages that can be secured can be only as long as the keys that can be generated. However, in identification only a very small part of the message needs to be secured, which in computational security triggers padding and thus waste, but on the other side makes information-theoretic security accessible and not so expensive.

At the same time, the security of identification implicitly requires semantic security. It has been known for a while that hash functions provide information-theoretic strong secrecy. However, because the standard for information-theoretic security has been strong secrecy, before https://arxiv.org/abs/2102.00983 no efficient functions where known to provide information-theoretic semantic security.
We need an implementation of these type of functions so that we can integrate information-theoretic security into our identification project.

Supervisor:

[quantum] Realignment criterion and upper bounds in device-independent QKD

Description

This paper uses the partial transpose as a tool to derive upper bounds on device-independent QKD
https://arxiv.org/abs/2005.13511
In this project the goal is to try to generalize the above to the other tools like the reallignment criterion:
https://arxiv.org/abs/quant-ph/0205017
https://arxiv.org/abs/0802.2019

Prerequisites

basics of quantum information/quantum formalism

Supervisor:

[quantum] Semantic security of infinite-dimensional classical-quantum channels

Description

Generalize semantic security of classical-quantum channels to infinite dimensional channel (not necessarily gaussian)

Prerequisites

quantum information theory

Supervisor:

[quantum] Asymptotic continuity of restricted quantum relative entropies under general channels

Keywords:
quantum, relative entropy, Pinsker, reverse, inequality, information thoery, asymptotic, continuity

Description

Asypmtotic continuity is a property in the form of inequalities (classically known also as inequalities of the reverse-Pinker type) that is necessary to prove upper bounds on operational capacities.

The (quantum) relative entropy (also known as quantum divergence and classically also known as Kullbackt-Leibler divergence), can be used to define various entanglment measures many of which have a proven asymptotic continuity.

Of particular interest are the restricted quantum relative entropies defined by Marco Piani (https://arxiv.org/abs/0904.2705), many of which satisfy asymptotic continuity (A.S.)

In the above there are maybe 2-3 different proof styles.
We can group the results in the above as follows:

  • A.S. for entropy, conditional entropies, mutual information, conditional mutual information
  • A.S. for relative entropies with infimum over states on the second argument
  • A.S. relative entropies with infimum over state *and maximization over measurement channels*

The goal of the project is to generalize the last case to asymptotic continuity for relative entropies with infimum over state and maximization over *general* channels.

Possible new proof directions are

Prerequisites

Knowledge of quantum information is highly recommended/required.
Knowledge of matrix analysis will be a strong advantage.

Contact

roberto.ferrara@tum.de

Supervisor:

[quantum] Practical protocols for quantum synchronization in classical network

Keywords:
quantum, network, synchronization

Description

Prerequisites

Knowledge of quantum theory as provided by the course Algorithms in Quantum Theory or similar

Supervisor:

[quantum] Entanglement-measures upper bounds on device-independent distillable key

Keywords:
quantum, qkd, entanglement

Description

The goal of this work is to try to upper bound the device-independent distillable key in terms of locally restricted relative entropy of entanglement (an entanglement measure).

The following are relevant works/articles

Prerequisites

Strong background in quantum theory is required, preferably in quantum information theory, which is not covered by the course Algorithms in Quantum Theory

Supervisor:

Research Internships (Forschungspraxis)

Nonlinear Effects in Multi-Core Fibers

Keywords:
nonlinearity, optical communications, mcf, multicore fibers

Description

Space-division multiplexing (SDM), which consists in exploiting multimode fibers (MMFs) or multicore fibers (MCFs) instead of single mode ones, is one of the future optical communications architectures to increase data rates and network planning flexibility. The nonlinear properties of MCFs are of primary interest in assessing the usefulness of SDM against the current network. With this thesis, the student has the chance to work on a state-of-the-art topic in the field of optical communication systems, and progress quickly thanks to a tight (if desired) supervision. Would you be curious to know more about it? If so, just get in touch with me at paolo.carniello@tum.de (personal page https://www.ce.cit.tum.de/lnt/mitarbeiter/doktoranden/carniello/).

Prerequisites

-some knowledge on optical communications systems (e.g., Optical Communication Systems or Simulation of Optical Communication Systems Lab)

-some knowledge about communications engineering topics

Contact

paolo.carniello@tum.de
See https://www.ce.cit.tum.de/lnt/mitarbeiter/doktoranden/carniello/ for more info on the supervisor.

Supervisor:

Strong Coupling Multimode Fibers

Keywords:
Multimode fibers, Space-division multiplexing

Description

Space-division multiplexing (SDM), which consists in exploiting multimode (MMF) or multicore fibers instead of single mode ones, is one of the future architectures to increase data rates and network planning flexibility. A desired working condition for SDM is the so called strong-coupling linear regime, which is however not intrinsically achievable in common MMFs. With this topic, the student has the chance to investigate if it would be achievable with some new design. If you are curious about it, just send a mail to paolo.carniello@tum.de.

Prerequisites

Basics of Optical Communication Systems (see https://www.ce.cit.tum.de/en/lnt/teaching/lectures/optical-communication-systems/)

Contact

paolo.carniello@tum.de

Supervisor:

Neural Network-Based Signal Predistortion for Direct Detection Systems

Description

During the internship, the student will be researching the application of Neural Network-based signal predistortion to mitigate the effects of fiber chromatic dispersion in direct detection systems.

Prerequisites

  • basic Python skills beneficial

Supervisor:

Error correction for DNA storage

Description

DNA-based data storage is a novel approach for long term digital data archiving.

Due to the unique nature of writing and reading DNA, the channel associated with these processes is still relatively poorly understood and varies over different synthesis (writing) and sequencing (reading) technologies. The task of the student is to evaluate various decoding strategies for certain error-correcting schemes tailored for the DNA storage channel.

 

Prerequisites

- Basic principles of stochastic and algebra
- Channel Coding
- Information Theory

Supervisor:

Anisha Banerjee

[quantum] Quantum Machine Learning for Communication

Keywords:
physical, layer, quantum, machine learning, non-linear

Description

As part of an ongoing project with Huawei we are looking into quantum machine learning algorithms applied to decoding at the end of an optical fiber in the non-linear regime.

So far we have tried only the quantum version of k-mean clustering, however the goal is to test further quantum algorithms, in particular quantum support vector machines next, and their classical quantum-inspired counterpart.

The projects will involve reading the literature on quantum machine learning algorithms and quantum-inspired algorithms, find or come up with an implementation (this will involve the use of quantum libraries, in particular so far we have use qiskit), and benchmark the performance.

Prerequisites

Knowledge of quantum mechanics or quantum information is highly recommended.

Supervisor:

[identification] Simulation and performance improvement of identification codes

Description

Identification is a communication scheme that allows rate doubly exponential in the blocklemght, with the tradeoff that identities cannot be decoded (as messages do) but can only be verified.

The double exponential growth presents various challenges in the finite regime: there are heavy computational costs introduced at the encoder and decoder and heavy trade-offs between the error and the codes sizes.

The ultimate goal is to find a fast, reliable implementation while still achieving large code sizes.

Identification codes can be achieved by first removing the errors from the channel with regular transmission channel coding, and then sending a challenge though the corrected channel. For every identity i, The channenge is generated by picking a random input m and computing the corresponding output T_i(m) using a function T_i that depends on the identity. The challenge is then the pair m,T_i(m) and the receiver wanting to verify an identity j will verify whether j=i by testing the challenge. This is done by recomputing the output with T_j and verifying whether T_j(m)= T_i(m). The errors are reduced by ensuring that the various functions collide on a small fraction of the possible inputs.

It turns out that choosing good sets of funtions {T_i} is the same as choosing error-correction codes {c_i} with large distance, where now each codeword c_i defines a function by mapping positions m (sometimes called code locators) to symbols c_im of the codeword.
We can thus construct identification codes by choosing error-correction codes where we are only interested in the performance of the error correction encoders (we are not interested in the error-correction decoder or error-correction codes).

Your task will be speeding up the current implementations based on Reed-Solomon and Reed-Muller codes:

The coding will be in Python/Sagemath.
This work can accomodate multiple students.
The working language will be in English.

Environment: we collaborate with LTI. At LNT and LTI there is currently a lot of funding for research in identification. Therefore you will find a large group of people that might be available for discussion and collaboration.

Prerequisites

Nachrichtentechnik 2

 

Supervisor:

[quantum] Realignment criterion and upper bounds in device-independent QKD

Description

This paper uses the partial transpose as a tool to derive upper bounds on device-independent QKD
https://arxiv.org/abs/2005.13511
In this project the goal is to try to generalize the above to the other tools like the reallignment criterion:
https://arxiv.org/abs/quant-ph/0205017
https://arxiv.org/abs/0802.2019

Prerequisites

basics of quantum information/quantum formalism

Supervisor:

Seminar Topics

The three Seminars "Seminar on Coding and Cryptography", "Seminar on Digital Communications" and "Seminar on Optical Communications" are organized jointly.

You can find more information at Seminar Topics.