Dear subscribers of the colloquium newsletter,
we are happy to inform you about the next dates of our Communication Technology Colloquium.
Thursday, October 22, 2020
Speaker: Luis Maßny
Time: 10:00 a.m.
Location: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09
Meeting-ID: 979 0415 7921
Passwort: 481650
Master Lecture: Analysis and Optimization of Multi-Kernel Polar Codes
Polar codes are a class of
linear block codes that exploit the channel polarization
effect in order to provide good error correction capabilities
at a low complexity. The channel polarization is based on a
recursive channel transformation by a so-called polarization
kernel. As a generalization of conventional polar codes,
multi-kernel polar codes have been proposed, which allow it to
combine polarization kernels of different sizes wihtin a
single code. Accordingly, these codes provide many degrees of
freedom, which makes it important to properly design such a
code in order to optimize its performance. Two major aspects
of the multi-kernel polar code design are analyzed in this
thesis. Firstly, the design of good polarization kernels for
practical codeword lengths is studied. Secondly, the effect of
applying a chosen set of polarization kernels in different
orders is approached.
In order to systematically
construct polarization kernels, a recursive construction rule
is developed that describes each kernel as a concatenation of
smaller kernels. The performance analysis is based on the
computation of Z parameters of the polarized information bit
channels for binary erasure channel. These yield an upper
bound on the block error rate. The observations by error rate
simulations over an additive white Gaussian noise channel.
The results show that the
kernel design depends on the code rate. In particular, it is
demonstrated that in some cases an asymptotically suboptimal
kernel is the best choice. The optimization of the kernel
order in general turns out to be complex and depending on a
variety of code parameters.
and
Thursday, October 22,
2020
Speaker: Egke Chatzimoustafa
Time: 11:00 a.m.
Location: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09
Meeting-ID: 979 0415 7921
Passwort: 481650
Bachelor Lecture: Playback Methods for Multichannel Immersive Binaural Sound
Reproducing spatial audio recordings with headphones allows listeners to perceive sound signals in 3D, where the listeners evaluate the differene between the recorded signals at both ears to localize sound sources. For a more immersive reproduction, sound sources should appear fixed in space in the case of head rotations. So for, several immersive reproduction methods like Motion Tracked Binaural Sound (MTB) and Binaural Cue Adaptation (BCA) were proposed. where BCA works with two microphones while MTB requires a larger number of microphones. The goal of this bachelor's thesis is to extend the BCA algorithm for more than two microphones and to evaluate this new multichannel system in terms of source localization and binaural cue modification.
The thesis show how additional microphones in
the multichannel system can be used to improve the sound
source localization. reducing the estimation error also
for low Signal-to-Noise Ratio (SNR) values. Furthermore,
several experiments show that the additional microphones
could solve the front/back confusion and could also
discriminate sources that are at the top and bottom,
regarding the head model. It is further shown how
additional microphones can be employed in the cue
modification algorithm. Several experiments confirm that
additional microphones could increase the quality,
modifying coherent components, and reducing incoherent
power error and coherent-to-incoherent power ratio error.
As the last extension, an adaptive reference channel
selection algorithm is introduced that paramerizes the cue
modification based on the optimal reference channel. For
larger head movements of the listener, this extension can
further improve the quality and even eliminate
modification errors for certain head orientations.
All interested parties are cordially invited, registration is not required.
General information on the colloquium, as
well as a current list of the dates of the Communication
Technology Colloquium can be found at:
http://www.iks.rwth-aachen.de/aktuelles/kolloquium
-- Irina Ronkartz Institute of Communication Systems (IKS) RWTH Aachen University Muffeter Weg 3a, 52074 Aachen, Germany +49 241 80 26958 (phone) ronkartz@iks.rwth-aachen.de http://www.iks.rwth-aachen.de/