Persönlicher Status und Werkzeuge

Open Theses

You may also contact one of our doctoral candidates directly, if you are interested in a Bachelor or Master thesis, a student job, an "Ingenieurspraxis" or a "Forschungspraxis". It often happens, that topics are being prepared which are not adverdised yet. It may also be possible to find a topic matching your specific interests.
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).

Bachelor or Master Theses


Development of a powerline communication PHY layer and channel simulator
The task of the (OSI) PHY layer in a communications system is the physical transmission of data. At the transmitter side, the PHY accepts packets from the MAC layer and transmits them to the receiver. At the destination, the PHY receives the data and passes the packet to the MAC layer of that device.
The student's task is to build a MATLAB simulator which takes packets from transmitters and delivers them to receivers. It has to drop and delay some packets with respect to different criteria. The connection to transmitters and receivers (clients) has to be done through D-Bus over the MATLAB Mex interface.
Prerequisites: Good programming skills, digital communications and basic knowledge about Linux.
Supervisor: Karl-Tasnad Kernetzky

Development of a hardware powerline channel emulator
The channel characteristics for powerline communications can be considered quite harsh. Plenty of interfering devices, different kinds of noise, high attenuation and signal reflections disturb communication. In order to test powerline modems, there has to be a reliable and reproducible way of disturbing signals.
The student's task is to build a hardware channel emulator which is controllable over Ethernet. The attenuation, different noise sources and filters should be included in the device.
Prerequisites: Some programming skills, digital communications.
Supervisor: Karl-Tasnad Kernetzky

Master/Diploma Theses


A Deterministic Approach to the Gaussian Multiple-Input Multiple-Output (MIMO) Broadcast Channel
Multi-user communication systems (such as wireless systems) are different than point to point channels in two key aspects; namely, the broadcast nature of transmissions (e.g., wireless transmissions can be picked up by any receiver in the vicinity of the transmitter) and the superposition (e.g., a wireless receiver picks up a linear combination of transmissions from all transmitters in its vicinity). Recently a deterministic approach to multi-user information theory has proved promising by achieving progress in some of the long-standing open problems by finding approximate solutions. The idea behind a deterministic approach, on a high level, is to focus on the interaction of signals rather than the background noise, through a simpler appropriate model; find exact solutions for the simpler model; and then translate the intuitions and techniques to new techniques and/or approximate solutions on noisy models.
The goal of thesis is to undertake a deterministic approach to Gaussian MIMO broadcast channels.
Prerequisite: Linear Algebra, Information Theory
Supervisor: Shirin Saeedi

Role of Feedback in Broadcasting
This project intends to investigate the role of feedback in broadcast channels. More information available upon request. Pre-requisite (at least one of the following):
Basic knowledge of Network Coding (see [2])
Basic knowledge of Algorithms
Basic knowledge of Information Theory
Supervisor: Shirin Saeedi

Bayesian inference and tracking techniques for non-Lorentzian lineshape optical sources

Project description
Research on optical communication systems is nowadays focusing on methods and technologies which would allow higher capacity and increased transmission distance. The capacity of optical communication systems can be increased by a combination of spectrally efficient modulation formats and advanced receiver design. Currently, commercially available optical communication systems employ modulation formats that carry 2 bits/symbol/polarization, such as quadrature phase shift keying. In the near future, it is expected that in order to satisfy capacity demands, it will be required to increase the spectral efficiency to 4 or even 6 bits/symbol/polarization. This would require moving to 16 or 64 quadrature amplitude modulation (QAM).
Moreover, there is a strong focus on designing optical systems with reduced footprint and this requires large scale integration of optical components including semiconductors lasers. The semiconductor lasers exhibit a non-Lorentzian lineshape due to carrier induced frequency noise. This noise presents itself mainly as a resonance peak on the frequency noise power spectral density (PSD), which has been shown to play an important role on the system performance [4]. If phase noise tracking algorithms are not properly designed a large penalty in system performance may be obtained for higher order modulation formats (> 16 QAM) [4-5]. For non-Lorentizan lineshape more sophisticated tracking algorithms are therefore needed as the physics behind the laser phase noise process needs to be taken into account. As a proof-of-principle, it has been demonstrated theoretically and experimentally that Bayesian filtering methods are an effective tool in tracking phase noise that exhibits non-Lorentizan lineshape [5-6]. One of the challenges with Bayesian tracking methods is that they require knowledge of the parameters of the state-space describing the system. This is especially challenging to infer from the measured data due to the high dimensionality of the state-space as well as that the measured systems have typically a large number of unknown variables [7].

Objectives of the project
The main topic of this Master Project is implementation of Bayeisan inference techniques for parameter identification of state-space model for optical sources exhibiting non-Lorentzian lineshapes. The student will develop framework for parameter estimation based on expectation maximization which is an iterative approach for maximum likelihood parameter estimation. The inferred knowledge about the state-space will then be used to formulate digital signal processing algorithms for carrier phase noise compensation for coherent optical communication systems. If time allows, the student will test the framework on experimental data obtained for an optical transmission systems employing long haul transmission and higher order model formats.

Relevant literature
[1] Govind Agrawal, Fibre-optic communication systems, 2010
[2] Dirk van der Borne, PhD Thesis, 2008
[3] Essiambre et al., Journal of Lightwave Technology, vol. 28, 2010
[4] M. Piels, in Proceedings of OFC 2015
[5] L. Barletta, Journal of Lightwave Technology, vol. 30, no. 10, 2012
[6] D. Zibar, Journal of Lightwave Technology, vol. 33, no. 7, 2015
[7] C M. Bishop, Pattern recognition and machine learning, 2006

Supervisor: Luca Barletta, Darko Zibar (DTU)

Modulation and Channel Coding

Scope:I offer master thesis topics in the area of modulation, signaling and channel coding. The goal is to design transmission schemes for reliable communication close to the theoretical limits. We consider wireless, optical and wired communication channels and take power, bandwidth, and latency constraints into account.

Prerequisites: you should have attended one or more of the following courses: Information Theory, Channel Coding, Coded Modulation, Channel Codes for Iterative Decoding.

Start: Summer 2016.

Supervisor: Georg Böcherer

Code Design for Secrecy

We are looking for motivated students to work on code design for secrecy. For realistic channel models, we want to test different codes out there to analyse its complexity, secrecy performance. The thesis basically consists of code design for security primitives with given range of channel parameters, desired block lengths and BERs.

Interested students can directly send their CVs and transcripts to my email address.

Supervisor: Onur Günlü

Probabilistic Signal Shaping for Short-Reach Optical Fiber Systems
Optical fiber systems form the backbone of the internet. Despite their large usable bandwidth, they are going to running out of capacity due to an increasing demand for services such as high-definition video streaming. In order to obtain the largest possible transmission rates for a fixed link, a non-uniformly spaced input can replace the common uniform input. Prerequisites for this thesis: digital communications (must!), basics in optical communication systems (important), information theory (equally important). If you are interested in this work, please contact me at tobias.fehenberger@tum.de to set up a personal meeting.
Supervisor: Tobias Fehenberger

Efficient Algebraic Decoding of Subspace Codes for Network Coding
Subspace codes were proposed by Kötter and Kschischang in 2008 for error control in random linear network coding (RLNC). The main idea is to encode information by the choice of a subspace rather than a choice of a vector. A basis for the selected subspace is then transmitted over a channel. The decoder returns the subspace that is closest to the received subspace according to some metric.
I offer topics on efficient (list and unique) decoding algorithms for subspace and rank-metric codes that allow to correct errors beyond the unique decoding radius.

Prerequisites:
You should be interested in Channel Coding and should have good knowledge in (linear) Algebra.
Supervisor: Hannes Bartz

Numerical evaluation of capacity for phase noise channels
Supervisor: Luca Barletta

MIMO Multiport Communications
The topic of the thesis is to develop a simulator for MIMO communications including the transmit and receive RF frontends of a single user link. The simulator should be able to support different types of antenna elements and array configurations as well as matching circuits and amplifier models. In addition it should be able to estimate rates of communication over deterministic and stochastic channels.
Supervisor: Andrei Nedelcu

Rate-Distortion Theory for Sparse Sources
Rate-Distortion Theory for Sparse Sources This project investigates information theory limits for the lossy compression of sparse sources. Motivated by the recent mathematical theory Compressed Sensing that deals with the efficient acquisition and reconstruction of sparse signals, we try to determine the fundamental limits of digitally storing data created by such sources. A sparse source emits a string of symbols of which - loosely speaking - only a few contain information. There are different ways to model these sources. An example is the Gaussian spike source which emits a Gaussian symbol with probability p and a zero with probability 1-p.

Possible directions of a project are:
- Investigating different source models
- (Numerically) determining the rate distortion function of a sparse source
- Computing finite length performance bounds for sparse sources

Prerequisites:
- Information Theory (must)
- Pleasure with mathematics (must)
- Multiuser information theory (beneficial)
Supervisor: Lars Palzer

Ingenieurspraxis


System Integration at Fraunhofer-EMFT
fuer die Bereiche: Entwicklung von Sensorsystemen, Systemintegration sowie Hard- und Softwareentwicklung mit folgenden Schwerpunkten:
1) Elektronikentwicklung, Design und Aufbau von Platinen, Programmierung von Mikrokontrollern
2) Integration und Charakterisierung von Sensorsystemen (Aufbau- und Verbindungstechnik, Messtechnik)

Fuer die Aufgabenstellung in der Systemintegration, speziell fuer Sensorsysteme und Sensornetze, suchen wir motivierte Studenten, die selbstaendig und eigenverantwortlich im Rahmen von Forschungs- und Entwicklungsprojekten arbeiten wollen. Es erwarten Sie spannende Arbeiten auf den Gebieten der aktuellen Forschung und Entwicklung in unseren modernen Laboren.

Kontakt: franz.wenninger(at)emft.fraunhofer.de
Supervisor: Gerhard Kramer, Franz Wenninger, Fraunhofer-EMFT

Forschungspraxis or MSCE Internships


Coding Techniques for Natural Language Processing
In this internship the student will review current state-of-the-art techniques for Natural Language Processing (with a focus on Machine Translation). Specifically, the student will check which of these techniques employ Hidden Markov Models, and whether they have connections to decoding algorithms for channel codes. Finally, the student should present a recommendation if, and how, list decoding methods can be applied in machine translation.
Supervisor: Ali Amjad, Bernhard Geiger

Development and Integration of a Demonstrations System for Advanced Communication Techniques
Development and integration of a demonstrations system for advanced communication techniques, which operate in an embedded Platform based on a combined ARM/FPGA System on Chip (SoC) architecture.

The activities to be carried out will start with the basic build of the system. This includes building and installing an appropriate Linux distribution on the ARM processor and making sure that all peripherals, particularly the FPGA, are accessible. After this initial stage the boards will need to be incrementally programmed to allow in the end full wireless communication between a transmitter and a receiver. Programming will be done in the first stage mostly in C / C++ and in the Linux shell, and in later stages also in VHDL/Verilog. Given the relatively high complexity of the task only students having good programming skills and a good understanding of the Linux operating system can be considered. An independent working style and the ability to solve relatively complex programming tasks is of advantage.

For more information, look here.
Supervisor: Tudor Ninacs, DLR

Open Student Jobs

no news in this list.


Theses in Progress

Bachelor Theses


Mohamed Aziz Ben Slimane: DVB-T transmission with GNURadio and USRP
The main purpose is to set up a standard compliant DVB-T transmitter in software (GNU-Radio) that can be used to broadcast a webcam signal via USRP. The receiver will consist of a commercially available USB Dongle. The transmitter should be designed to support different codecs as well as different code and modulation schemes that are standard compliant. It should also allow the injection of a virtual channel (including noise, frequency and phase offsets) to test the adaptability of the transmission scheme.
Supervisor: Andrei Nedelcu

Tobit Klug: Modelling and Mitigation of impulsive noise in PLC transmission system
Supervisor: Elisabeth Oberleithner

Matthias Engelhard: Erstellen von Spezifikationen und Testplänen sowie Dokumentation für Skriptprogramme
Supervisor: Gerhard Kramer, Continental Automotive GmbH, 93055 Regensburg, Dr. Kelbeck

Georg Maringer: Real-time communications
This thesis investigates the problem of communicating, in real-time, an autoregressive process over a discrete memoryless channel.
Supervisor: Roy Timo

Muhammed Efe: Candy Crush Codes
Candy Crush Codes [1] are a stupid idea for non-linear block codes whose constraints are taken from the game rules of Candy Crush Saga. Although the codes themselves will not be "good" in a communication-theoretic sense, they are at least interesting in their combinatorial properties or for didactic reasons. Moreover, even though the first step will be to look at block codes, it should be possible to encode and decode also sequentially, essentially admitting infinite blocklengths.

This research internship should investigate the code's combinatorial properties (i.e., rate as function of field size and candy flavors), en- and decoding schemes, error probabilities for M-ary symmetric channels, and, if possible, improve code design such that the codes become useful (e.g., have a guaranteed Hamming distance). At the basis of all these investigations is of course a detailed literature survey of nonlinear codes with two-dimensional constraints.

[1]: Blog Post
Supervisor: Bernhard Geiger, Andrei Nedelcu, Luca Barletta

Alberto Diago Gallardo : Atmospheric Influence on Free Space Optical Communications
The work is based on Free Space Optical (FSO) communications and will include the following parts: • Case Study: Ground-to-Ground laser Links: o Link budget calculations; (Done) o Tracking Power budget calculations; o Scintillation analysis (optional: atmospheric simulations and fade statistics); (Ongoing) o Atmospheric Attenuation: Link availability calculations. (Ongoing) • Support the design, integration of testing of the “Frame-Steering Concept” as a demonstrator terminal for static links. (Ongoing) • Outdoor link demonstration and measurement campaign. • Analysis and evaluation of the measurement data.
Supervisor: Norbert Hanik, Luis Martin Navajas

Daniel Külzer: Interference Coordination in a Local Area Scenario

The performance of current cellular networks is degraded by interference between neighboring cells (so called inter-cell interference). It can be improved if the base stations share the channel state information of the useful and interfering links. With this information the base stations can coordinate their transmission strategies. This is called interference coordination.

One form of interference coordination is large-scale MIMO. For many antennas at each base station it is possible to null the interference caused to other users, while serving the users associated to the base station.

The student should implement large-scale MIMO and compare it to network MIMO in a local area scenario.

Prerequisite: Linear Algebra, Digital Communications (Nachrichtentechnik)

Supervisor: Stefan Dierks

Master/Diploma Theses


Frank Löw: Identification, Development, and Simulation of Protocol Concepts for a Battery-Driven Backbone-Router
The aim of this thesis is to develop low-power protocols for a multi-hop backbone network in a wireless sensor network.
Supervisor: Youlong Wu, Shirin Saeedi, Hekatron Vetriebs GmbH, Philipp Alber

Yuchen Wu: Higher-Order Markov Aggregations
In [1], we used an information-theoretic characterization of lumpability as a cost function for Markov chain aggregation, i.e., for replacing a Markov chain on a large state space by a Markov chain on a smaller state space. We showed that the cost function can be interpreted as the Kullback-Leibler divergence rate between the original chain and chain that is obtained by lifting the aggregated one. We furthermore showed that by relaxing the problem, the information bottleneck method can be used for obtaining the aggregation.

This thesis should extend the work to higher-order aggregations, i.e., to replacing a Markov chain on a large state space by a higher-order Markov chain on a smaller state space. Higher-order Markov chains allow for smaller modelling errors but come at the cost of a higher model complexity -- investigating higher-order aggregations thus admit trading one design goal for the other.

The main questions are whether the corresponding cost function can also be interpreted as a Kullback-Leibler divergence rate and whether the information bottleneck method can again be employed for aggregation. In case we find a lifting that admits an interpretation as a Kullback-Leibler divergence rate, it is worth changing the lifting method to the one presented in [2], investigating connections to the spectral theory of Markov chains.

[1]: B. C. Geiger, T. Petrov, G. Kubin, and H. Koeppl, “Optimal Kullback-Leibler aggregation via information bottleneck,” IEEE Trans. Autom. Control, vol. 60, no. 4, pp. 1010–1022, Apr. 2015, open-access: arXiv:1304.6603 [cs.SY].
[2]: K. Deng, P. G. Mehta, and S. P. Meyn, “Optimal Kullback-Leibler aggregation via spectral theory of Markov chains,” IEEE Trans. Autom. Control, vol. 56, no. 12, pp. 2793–2808, Dec. 2011.
Supervisor: Bernhard Geiger

Nicolas Blum: Algorithm Development for FFT-based FM Multitone Signal
Supervisor: Andrei Nedelcu, Joerg Biedermann (Rohde & Schwarz)

Tobias Prinz: Polar Codes
Supervisor: Georg Böcherer

Sara-Lee Steffan: Development and design of an optical transceiver module
Supervisor: Norbert Hanik, Philipp Putzer (OHB System AG)

Ingenieurspraxis


Dominik Fienko: Integration BS2000 SE Serie in Enterprise System Management
Supervisor: Gerhard Kramer, Fa. Fujitsu Technology Solutions, PDG ES S SWE 057, München

Mahmoud Marcam Helmy: Erstellung einer App für Smartphones der BITS mobile ERP Linie auf Basis von IOS Plattformen
Supervisor: Gerhard Kramer, BITS better it solutions GmbH, Wallenmahd 47, A-6850 Dornbirn

Ulrich Patrick Sandoval: Weiterentwicklung des Netzwerkanalysetools (NAT) mit Schwerpunkt auf Testfälle
Supervisor: Gerhard Kramer, Fa. Infineon Technologies, Neubiberg, Hr. Lippmann

Hasan Yagiz Özkan: Image Tracking Algorithm Development
Supervisor: Gerhard Kramer, Fa. Bases Teknoloji Arge Sanay, Hr. T. Cirak, Istanbul

Burak Tas: Analog- und Digital-Radio: Konzeption und Automatisierung von Testspezifikationen
Supervisor: Gerhard Kramer, Telemotive AG, Breitwiesen, 73347 Mühlhausen

Lukas Püttner: Evaluierung verschiedener Tools zur Extraktion und Auswertung von Metadaten aus IP-Verkehrsdaten
Supervisor: Norbert Hanik, ESG Elektroniksystem- und Logistik GmbH, 82256 Fürstenfeldbruck

Francesco Montanari: Dynamic Dead Pixel Correction
Supervisor: Norbert Hanik, Fa. ARRI, Arnold & Richter Cine Technik GmbH & Co KG, München, Fr. E. Kögel

Jonathan Roth: Referenz-PLL mit umschaltbarer Zeitkonstante
Supervisor: Norbert Hanik, Fa. Rohde & Schwarz GmbH & Co. KG, 81671 München

Forschungspraxis (12 ECTS)


Liu Xiaotong: Simulator in Matlab for MIMO Multiport Communications
The purpose is to build a Matlab simulator that can incorporate both circuit and channel models for MIMO communications in order to evaluate the achievable rates with different RF front-end designs in various propagation scenarios.
Supervisor: Andrei Nedelcu

Edvarts Berzs: Waveforms for Air Interface of 5G

5G:
- Air Interface Candidate Filtered-OFDM (f-OFDM)
- Multiple Access Scheme Sparse Code Multiple Access (SCMA)

Themeninhalte:
- Unterstützung bei der Untersuchung zukünftiger technischer Entwicklungen im Mobilfunk (2 Wochen)
- Recherche und Aufarbeitung wissenschaftlicher Publikationen (2 Wochen)
- Implementierung und Validierung von Signalverarbeitungsalgorithmen in Matlab und C++ (4 Wochen)
- Definition und Umsetzung automatisierter Tests mit Hilfe moderner Messtechnik (1 Wochen)

Supervisor: Stefan Dierks, Florian Schlembach (Rohde & Schwarz)

Julian Renner: High-dimensional Probabilistic Shaping for Optical Communication Systems
Project description

Coded modulation is a technique to match the communication system to the communication channel. In this Forschungspraxis, the focus is on shaping the symbol probabilities of QAM input for an optical communication system to achieve high spectral efficiency.

Supervisor: Georg Böcherer, Tobias Fehenberger

Forschungspraxis (6 ECTS)


Delcho Donev: Constellation Shaping for Satellite Communication
Coding and modulation for bandwidth limited satellite communication is considered. In this internship, the position and probability of constellation points should be optimized and evaluated in terms of achievable rate and adaptability. Comparisons should be made to the existing APSK constellations used, e.g., in the DVB-S2 standard.
Supervisor: Georg Böcherer, Gianluigi Liva

MSCE Internships


Hussein Hammoud: Lossy Compression of the Bernoulli-Gaussian Spike Source in the Finite Blocklength Regime
The subject of this research internship is lossy compression for the Bernoulli-Gaussian (BG) spike source. This source emits independent and identically distributed random variables each of which is the product of a Bernoulli random variable with and an independent Gaussian random variable. We are interested in the optimum coding rate for a given finite block length subject to the constraints that source symbols which are equal to zero are reconstructed as zeros and those that are not equal to zero satisfy an average squared error distortion constraint.
Supervisor: Lars Palzer