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*
*Speake**r:* 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*
*Spe**aker: *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(a)iks.rwth-aachen.de
http://www.iks.rwth-aachen.de/