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


Rate-adaptive Coded Modulation for low SNRs
Supervisor: Markus Stinner

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

Analysis of Backhauling Techniques for Full-Duplex Communication Networks
The thesis will investigate the back-hauling techniques for a full-duplex communication network involving an LTE base station that connects the users to the backhaul through a satellite. For example, consider a set of users in a coach of a train that are connected to a base-station (LTE) located on the coach which has a link to the satellite. Such scenarios are of interest in providing data and voice communication in various transport systems and also to certain cases of disaster hit regions. The network can be modelled as a type of relay channel which admits a broadcast and multiaccess (MAC) components.
The thesis involves modelling the information-theoretic framework for the rate region of the network, a comparison with traditional half-duplex methods, and an extension to Gaussian and Ricean fading satellite channels. You should have a strong interest in information theory and digital communications, and you should be comfortable with MATLAB. Knowledge in satellite communications will be of benefit.
The thesis is co-supervised by the DLR.
Supervisor: Georg Böcherer, Dr. Mohit Thakur, DLR

Powerline Communication for industrial application
Powerline Communication (PLC) is a well established technology for in-building data transmission. The HomePlug standard provides an easy to use interface. PLC is charackterized by modulation and coding schemes which ensure robustness against impuslsive noise and disruptions by the power transmission and transformation. Hence, the PLc becomes an interesting approach for industrial applications such as power charging stations for electrical cars or in the field of smart grid. This Master thesis shoudl analyze the PLC technology on the basis of the HomePlug Greenphy standard and its realization in todays chipsets. In particular, the optimization of the given PLC realizations for industrial use will be the focus of this work. This MAster thesis will be done in cooperation with Siemens AG Corporate Technology.
Supervisor: Elisabeth Oberleithner

Open Student Jobs

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Theses in Progress

Bachelor Theses


Alexis Gonzalez-Argüello: Development of a Computer Implementation of Computational Methods for Time-harmonic Electromagnetic Field Modeling
Supervisor: Gerhard Kramer, Stellenbosch-University, South Africa, Prof. M. Botha

Ekin Alican Igdir: Cooperative Communication using Software Defined Radio
Topic:

By using software-defined radio (SDR) equipments, the development of communication systems can be done totally in software. This allows quick prototyping of communication systems and testing them on real scenarios under real channel conditions.

In our institute, we have SDR equipments that can be used for this purpose. The aim of this work is to build a communication systems to test and evaluate the performance of different relaying techniques. The tasks of the student can be listed as follows:

  • Literature review on the relaying techniques and their theoretical performance evaluation,
  • Implementation of the techniques with SDR,
  • Performance evaluation of the techniques according to different criteria (transmit power, relay location, resource allocation parameters, etc.),
Requirements:
  • Interest in the topic,
  • Background in communications engineering topics,
  • Programming skills (in MATLAB),
  • Experience with software defined radios (especially with USRP) and GNURadio is not mandatory, but is a plus.
References:
  • More information about SDR and USRP in Wikipedia
  • Kramer, G., Marić, I., & Yates, R. D. (2006). Cooperative communications. Foundations and Trends in Networking, 1(3), 271-425.
Supervisor: Onurcan İşcan

Mahmoud Maryam ? 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

Firat Beytemür: Implementation of a ADS-B Receiver

Automatic dependent surveillance-broadcast (ADS-B) is a technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. In this work, the student should understand the basics of this technology and implements a receiver to decode ADS-B signals.

ADS-B signals are transmitted over a carrier at 1090MHz with a bandwith of about 50kHz. These signals can be easily received with the software-defined radio (SDR) equipment we have at our institute and can be processed with standard computer equipment. The tasks for this work can be summarized as follows:

  • Understanding the basics of the ADS-B technology.
  • Learning the basics of software-defined radio concept.
  • Baseband processing of the ADS-B signals (estimation, synchronization, etc.)
  • Decoding of the information included in the ADS-B frames.
  • Implementation of a graphical user interface
Supervisor: Onurcan İşcan

Alexander Jesipow: Durchführung von manuellen und automatisierten Testprozeduren mit ALEXA und AMIRA Filmkameras
Supervisor: Fa. ARRI,München, Hr. O. Gonschorekt

Arda Can Özensoy: How many cars can YOU park?
Alfred Renyi wrote a curious paper in the late 1950s: He assumed an infinitely parking lane and placed cars, all equally long, randomly on this lane. He found out that you cannot even use 75% of the available parking space [1]!
But I bet you can do better by a more realistic model: Assume cars are between 3 and 6 meters long, and assume that if a car arrives at the parking lane, it will take the first free parking slot (into which it fits). Cars arrive and leave randomly and independently.
The first part of the Bachelor's project is to write a Matlab simulation and determine the efficiency of this parking scheme. Besides some knowledge in Matlab, for this task you should know a little bit about stochastic processes and random variables. The second part involves a literature survey, where you shall find out how this parking/packing problem connects with communications engineering (e.g., code design, communication networks, etc.).

[1]: Renyi's Parking Constant on Wolfram Mathworld (with illustration)
Supervisor: Bernhard Geiger

Hiba Arnout: Implementation of an Efficient Lumping Algorithm
In 2003, Derisavi, Hermanns, and Sanders proposed an efficient algorithm to detect the coarsest partition of the state space, w.r.t. which a given Markov chain is lumpable. The algorithm is based on splitting a set of states which violates the conditions for lumpability into sets which satisfy them; it is shown to have a computational complexity of O(m log n), where n is the number of states of the Markov chain and m the number of transitions (i.e., the number of nonzero entries of its transition probabilities matrix).

The task of the project is to implement this algorithm in a modular way, such that the condition for lumpability can be exchanged by either information-theoretic criteria or by criteria for quasi-lumpability. Finally, a series of experiments should verify the functionality of the algorithm and assess whether a this splitting method can effectively detect a quasi-lumpable partition.
Supervisor: Bernhard Geiger

Master/Diploma Theses


Martinez Laura Pastor: SDR based experimental setup for evaluating system performance with QAM and differential PSK
The purpose of this thesis is the application of Software Defined Radio (SDR) as an experimental environment for investigating the performance of various modulation schmemes. Besides, this work should provide an insight into the possibilities SDR offers and its application, not only in an educational but also in the research context.
Supervisor: Elisabeth Oberleithner

Tobias Fülle: Preamble Recognition on NC-OFDM for Dynamic Synchronization
Within a public subsidized research project called COUWBAT, the student will develop a combined ultra-wide band and cognitive radio HW-Transceiver to increase the spectrum efficiency and data rates through the utilization of the so-called white spaces for secondary users. Therefore, the NC-OFDM method will be applied to switch certain subcarriers on and off. Later on, evaluation of FilterBank Multicarrier (FBMC) is aimed to take place.
Supervisor: Onur Günlü, M. Sc. Manuel Sáez Rodríguez (AED Engineering)

Jonas Eichler: Device To Device Communication in LTE Mobilfunksystemen
Device to Device (D2D) Kommunikation wird momentan in der Version 12 (Release 12) von LTE spezifiziert. Im Rahmen Ihrer Abschlussarbeit fertigen Sie Studien über die Standardisierung von D2D an und erarbeiten ein Modell des Physical Layers. Besonderer Augenmerk soll hierbei auf die Aspekte der Discovery Prozedur sowie auf die D2D Datenkommunikation gelegt werden. Ihre Studien und Implementationen, welche hauptsächlich in MATLAB erfolgen, werden dann zur Implementation und Verifikation unseres User Equipment Testsystems genutzt. Sie arbeiten während Ihrer Arbeit innerhalb des bestehenden Projektteams für die LTE Implementierung mit. Eine gute und verständliche Implementation der Modelle ist deswegen ebenso erforderlich wie eine einwandfreie Dokumentation.
Supervisor: Stefan Dierks, Dr. Moritz Harteneck (Rohde & Schwarz)

Zhaoqi Zhu: Preamble-based Channel Estimation in Coherent Spatial Division Multiplexing OFDM Transmission System
The robustness of the channel estimation is a key for coherent spatial division multiplexing OFDM transmission system. Time-multiplex(TM) preamble structure has been widely adopted in the polarisation division multiplexing OFDM transmission and in the scenario of spatial division multiplexing OFDM transmission supporting 3 spatial modes. When scaling to higher number of spatial modes, the TM based channel estimation introduces huge overhead and is sensitive to laser phase noise. Therefore, subcarrier-orthogonal(SO) preamble structure is a potential candidate for channel estimation. In this work, the TM and SO preamble-based channel estimation will be investigated under the influence of laser phase noise, mode-dependent loss and strong/weak coupling regime of the few mode fiber.
Supervisor: Yingkan Chen

Stefan Thiel: Analysis of AM Demodulation in Speech-based Airborne Communications Under Multipath Propagation
This master thesis is in cooperation with the radio communications department at Rohde&Schwarz. Airborne radio communication is based on Amplitude Modulation (AM). To use them with existing low-directivity antennas in airplanes, the effects of multipath propagation have to be considered. The student will investigate the channel effects on airborne communications (Ground-Air, Air-Air) and compare possible receiver designs. For this aim, realistic multipath-propagation scenarios will be defined for airborne communications. The models and the suggested designs will be tested with Matlab/Simulink. The student will evaluate the results and compare multiple techniques to improve communication quality.
Supervisor: Onur Günlü, Dipl.-Ing. Ludger Korsmeier and Dipl.-Ing. Michael Gerth (Rohde&Schwarz)

Li Chen: Aggregation Methods for Markov Chains
The purpose of this thesis is to investigate state space aggregation methods using information-theoretic cost function. The main cost functions investigated shall be the I(Y_1;Y_2) and H(Y_2|Y_1) - H(Y_2|X_1). The former, which should be maximized, is related to information-theoretic clustering and to near complete decomposability of Markov chains. The latter, which should be minimized, is related to lumpability, the phenomenon of a function of a Markov chain being Markov. Both cost functions should be optimized over all possible partitions of the state space, which is a combinatorial problem.

In order to reduce the computational complexity of the search, sub-optimal aggregation methods shall be adopted from the literature: Agglomerative, sequential, or splitting methods shall be investigated. Furthermore, it is interesting to see if a relaxation of the cost functions admits the application of established algorithms, like the information bottleneck method.

The aggregation methods shall be evaluated at the hand of a few examples, e.g., quasi-lumpable and nearly completely decomposable Markov chains, examples from natural language processing or synthetic biology, and the Ehrenfest diffusion model.
Supervisor: Bernhard Geiger

QIPING SHAO: OFDM and FBMC
Supervisor: Patrick Schulte

Ingenieurspraxis


Robert Fellendorf: Untersuchung der HF-Parameter für die Eignung zum Einsatz in IM-Messgeräten
Supervisor: Gerhard Kramer, Fa. Rosenberger, Hochfrequenztechnik GmbH & Co. KG, 83413 Fridolfing

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

Daniel Klimsa: Integrated Spare Part Identification and Ordering
Supervisor: Norbert Hanik, Siemens AG, Dr. Blume

Ömer Tan: Zusammenstellen einer Messtechnikapplikation aus Standard HW/SW-Komponenten
Supervisor: Gerhard Kramer, BMW Group München, Hr. E. Zerlach

Martina Kiechle: Entwicklung eines Kapazitätsplanungstools und Erstellung einer SharePoint 2013 ShowCase Plattform
Supervisor: Gerhard Kramer, Siemens AG, München, Hr. C. Riedelbauch

Tamara Fiedler: Planung und Umsetzung von innovativen AR-Apps für alle BSH-Marken
Supervisor: Gerhard Kramer, Fa. BSH Bosch u. Siemens Hausgeräte GmbH, München, Hr. Clemens

Michael Koller: Integration von Referenzkurven in eine Messung eines Broadcast Signal Analyzers
Supervisor: Gerhard Kramer, Fa. Rohde & Schwarz GmbH & Co. KG, München

Mohamed Salah Ben Slimen : SDR - Digital Modulation Real Time Receiver in Simulink

Software Defined Radio is a relatively new concept in thinking and designing communications systems. What defines it is that almost all parts of a transciever (transmitter/receiver) are implemented as software modules on a general purpose computer, rather than on dedicated hardware. The radio frequency part of the receiver is thus also reconfigurable through software and will represent just an interface.

Simulink is a graphical programming tool from Mathworks and is especially good for fast prototyping and simulating of complex systems. It provides many custom made software modules and light and easy way to set up graphical user interfaces.

The purpose of this project is that following the principles of SDR radio and the facilities offered by Matlab/Simulink you could build a real-time receiver for DAB. DAB (Digital Audio Broadcasting) is a digital radio communication standard for broadcasting radio stations intended to replace the old fashioned AM and FM radio systems.

Links:

http://en.wikipedia.org/wiki/Software-defined_radio

http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting

http://de.mathworks.com/products/simulink/

Supervisor: Andrei Nedelcu

Nawel Attia: Nonlinear Error Correction Codes for Erasure Channels: Sudoku
Supervisor: Patrick Schulte, Bernhard Geiger

Forschungspraxis (12 ECTS)


Tobias Schneider: Distributed Reed-Solomon and Gabidulin Codes
Supervisor: Hannes Bartz

Andreas Lang: Implementing the Split-Step Fourier Method
The Nonlinear Schrödinger Equation (NLSE) is a nonlinear partial differential equation that describes the propagation of light in a nonlinear optical fiber. Since there is no closed-form solution to the NLSE, numerical methods are used to approximately solve it. The most popular among these methods is the split-step Fourier method (SSFM). The student’s task in this Forschungspraxis/Ingenieurspraxis is to implement the SSFM in Matlab-Enabled C (mex) with CUDA support.
Supervisor: Tobias Fehenberger

Yuchen Wu: Using Information Theory to Quantify Sudoku Difficulty
Sudoku games come in many difficulties; those with many clues are in general easier to solve than those with few clues. But is this a rule without exception? Or are there Sudokus with, say, 40 clues which are more complicated to solve than some Sudokus with 35 clues? If this is true, the number of clues is not a good measure of difficulty. Many other difficulty metrics depend on the runtime of a given solver, and hence depend on the implementation or the solving algorithm.
In this Forschungspraxis, the following assumption is made: Sudokus are easy to solve if the clues are highly redundant. And redundancy can be measured (or estimated) using information theory (see [1] and the references therein). There are already first attempts at information-theoretic difficulty ratings [2], and recently Sudoku puzzles have been considered as a method of coding for erasure channels [3]. The goal of this Forschungspraxis is to survey the existing literature, implement an information-theoretic difficulty rating and compare it to other, existing algorithm-based difficulty ratings. In the ideal case you will even find a new method to rate Sudokus, or you might discover a strong connection between difficulty ratings and parameters of Sudoku codes. In any case, this is a Forschungspraxis you can talk about at a student's party!

[1]: Griffith and Ho, "Quantifying Redundant Information in Predicting a Target Random Variable"
[2]: When Sudoku come across Information Theory
[3]: Atkins and Sayir, "Density Evolution for SUDOKU codes on the Erasure Channel"
Supervisor: Bernhard Geiger, Ali Amjad

Mustafa Cemil Coşkun: Staircase Codes for Optical Communications
Staircase codes are a relatively new class of algebraic channel codes for high-speed optical communications. Their large coding gains and reasonable decoding complexity have made them a promising option for data rates of 100 Gbit/s and more. The student's task of this Forschungspraxis is to understand the concept of staircase codes and implement them in Matlab or C.
Supervisor: Tobias Fehenberger, Georg Böcherer

MSCE Internships


Mu He: Link Adaptation Improvement for B4G
As an advanced version of LTE, B4G provides several new features. One of them is link adaptation based on measured instantaneous SINR which is used for selecting MCS and rank of transmission to generate the best throughput. In addition, depending on the scheduler, SINR may be used to determined which users are scheduled for a certain transmission time interval and on which frequency resources. The measured SINR can be inaccurate due to measurement errors, rounding errors due to quantization of the SINR values, and delay from time of measurement until the actual data transmissions.
To compensate for SINR inaccuracies, the SINR can be adjusted by a certain offset before being used for link adaptation and scheduling. This offset value, in our implementation, is adaptively adjusted for each user based on an algorithm via a feedback loop, referred to as Outer Link Loop Adaptation (OLLA).
My work is trying to raise the system performance of the simulation for B4G downlink and uplink by improving the adaptation behavior.
Supervisor: Gerhard Kramer, Dr. Volker Pauli, NOMOR Research