Lab "Real-Time Signal Processing"


Basic Information
Lecturers: Gerhard Schmidt and Bastian Kaulen
Room: -
Language: English
Target group: Students in electrical engineering and computer engineering
Prerequisites: Skills in C programming language (for the DSS part), basic MATLAB knowledge (for the LNT part), diverse coding skills (for the ICT part)
Registration procedure:

If you want to sign up for this laboratory, you need to register with the following information in the registration form

  • surname, first name
  • e-mail address
  • matriculation number
  • desired topic

Please note, that the registration period starts the 14.03.2022 at 00:00 am and ends the 06.04.2022 at 11:59 pm. All applications before and after this registration period, will not be taken into account.

Registration will be possible within the before mentioned time by sending a mail with your name and matriculation number to This email address is being protected from spambots. You need JavaScript enabled to view it..

The registration is binding. A deregistration is possible by sending a mail with your name and matriculation number to This email address is being protected from spambots. You need JavaScript enabled to view it. until Friday, 11.04.2022 at 11:59 pm. All later cancellations of registration will be considered as having failed the lab.

Requirements, rules and commitments depend on the chosen topic and will be announced at the preliminary meeting (attendance is mandatory).

Attendance at all of the final presentations on the 07.07.2022 at 14:00 o'clock is mandatory as well to pass the lab.


Preliminary meeting: 13.04.2022 at 12:00, online meeting

Final presentations: 07.07.2022 at 14:00

Contents: See the detailed introduction of the topics below.



ICT.1: Optical CDMA in a VLC Transmission System (1 group of 3 students, Prof. Dr.-Ing. P.A. Hoeher)

CDMA is a well-known orthogonal transmission scheme in time domain for multi-user scenarios in RF systems. In this lab, the optical variant of CDMA (OCDMA) is to be evaluated in terms of applicability and performance in optical free-space transmissions. With respect to RF systems, the main difference in incoherent optical system is the lack of constructive and destructive signal interference. Signals cannot be canceled out, as only the intensities are added up.

Two different variants should be taken into account: i) two transmitter LED are used independently with two different CDMA sequences and ii) one single LED is used with electrically combined CDMA sequences as single transmitter.

This lab utilizes software simulation for the main system analysis. Afterwards, a hardware setup will be provided for taking home or working in the TF lab (depending on the current situation) for a validation of the achieved simulation results.

Basic Python programming skills are required as well as basic digital signal processing knowledge.

Further contact: M.Sc. Adrian Krohn, ICT/NT, This email address is being protected from spambots. You need JavaScript enabled to view it.


ICT.2: Simulation of a MIMO Transmission System Using GNU Radio (1 group of 3 students, Prof. Dr.-Ing. P.A. Hoeher)

GNU Radio and its graphical user-interface, companion (GRC), are capable of steering software defined radio devices (SDRs). To perform the required signal processing and streaming, including system design, GRC delivers a broad toolbox from signal sources to signal processing.

As a preparation of real-world measurements inlcuding an SDR device, a MIMO system model shall be implemented using GRC. A data stream shall be transmitted using a beamforming strategy employing a suitable MIMO channel model. A suitable channel precoding shall be used and the data be recovered afterwards.

This lab utilizes free software for system simulation and real-world application. Due to the pandemic situation, the tasks can be done from the home office.

Basic Python understanding skills are required as well as advanced channel coding and related digital signal processing understanding.

Further contact: M.Sc. Nils Johannsen, ICT, This email address is being protected from spambots. You need JavaScript enabled to view it.

NT.1: QoT estimation with Reinforcement Learning (1 group of 3 students, Prof. Dr.-Ing. S. Pachnicke)

Accurate quality of transmission (QoT) estimation is essential to ensure proper operation of an optical transmission network. However, a multitude of linear and nonlinear effects as well as effects like component aging make an accurate estimation of the QoT difficult, leading to a waste of capacity, due to a variety of margins set to guarantee service.

Reinforcement learning (RL) is one of three basic machine learning paradigms, alongside supervised learning, and unsupervised learning. It is concerned with how intelligent agents should act in an environment to maximize the notion of cumulative reward.

In this project a Reinforcement learning algorithm for the estimation of the QoT of an optical transmission system is to be implemented in Python and its abilities to estimate the QoT accurately is to be evaluated.

Further contact: M.Sc. Alexandr Langolf, NT

NT.2: Let's break the nonlinear limit in an optical transmission system (1 group of 3 students, Prof. Dr.-Ing. S. Pachnicke)

Current optical fiber transmission systems are facing major challenges to handle the ever-growing global data traffic. The nonlinearity of the fiber is a limitation to further improve the spectral efficiency, since the systems are based on the assumption of a linear channel and are therefore not fully compatible. One possible solution to overcome this limitation is to use the nonlinear Fourier transform (NFT). The NFT is a solution of the idealized nonlinear Schrödinger equation that describes the propagation of light in an optical fiber, so that the nonlinearities are considered here.

In this project, a conventional linear system and a system using the NFT should be compared subjectively by transmitting a digital image. To do this, the students should program an image-to-bits and a bits-to-image converter in the chair's simulation tool MOVE-IT. An OFDM-like spectrum is then to be generated from the binary data, transformed once with an IFFT and once with an inverse NFT, and then transmitted through an optical channel. On the receiver side, an equalizer has to be implemented and the received images should be compared with each other and with the transmitted image in order to analyze the performance of the two systems used.

Further contact: M.Sc. Olaf Schulz, NT

DSS.1-3: Real-Time Audio Processing (3 groups of 3 students, Prof. Dr.-Ing. G. Schmidt)

In this project, students are going to implement a speech enhancement system in the Kiel Real-Time Audio Toolkit (KiRAT). Algorithms within this framework are to be programmed in C language, the graphical user interface is written in C++ using the QT framework. Thus, it is expected that the participants have programming skills in C/C++. There will be up to three groups of three students that will create their own speech enhancement systems. Each group will specialize on one of the following algorithmic components:

  • Analysis and synthesis filterbanks,
  • Noise estimation and
  • Noise reduction.

Further contact: M.Sc. Bastian Kaulen, DSS, This email address is being protected from spambots. You need JavaScript enabled to view it.


Schedule of talks

Attendance during all presentations as well as active paticipation in the discussions is mandatory to pass the lab.

The schedule can be found below:

07.07.2022 Group Topic Lecturer(s) Talk duration
14:00   Opening Bastian Kaulen 5 minutes
14:05 TBD TBD TBD 35 minutes


Current evaluation Completed evaluations