- Kommunikationstechnik-Kolloquium - lists.rwth-aachen.de

Einladung Promotionsvortrag
by Irina Esser 25 Feb '22

25 Feb '22

Sehr geehrte Abonnenten des Kolloquium-Newsletters, gerne laden wir Sie zu einem Promotionsvortrag ein. Vortragender: Herr Stefan Kühl, M. Sc. Thema: *Adaptive Algorithms for the Identification of Time-Variant Acoustic Systems* Zeit: Montag, 7. März 2022, 11:00 Uhr Zoom-Meeting: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 <https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09>Meeting-ID: 979 0415 7921 Passwort: 481650 Many digital speech and audio communication systems incorporate models of acoustic systems during signal processing. Often, the impulse responses of these acoustic systems have to be identified during or before using a communication system by means of adaptive algorithms. Acoustic systems describe how sound is affected during transmission between a source and a receiver. Examples of acoustic systems comprise rooms with reflections from boundaries and scattering from objects, communication devices such as smartphones or smart home devices, or even a human head where shadowing effects occur. In many situations, the impulse responses of these systems need to be identified. Possible scenarios are acoustic measurements or system identification in speech communication applications, e.g., for accoustic echo cancellation (AEC). Depending on the specific use case, vertain aspects have to be taken into account. For a measurement the excitation signal can be designed, whereas for speech communication applications the system's excitation is the speech signal that cannot be altered. Hence, for the latter case, correlation has to be considered during the system identification. In addition, the systems to be identified may vary over time when the acoustic environment changes, e.g., due to moving objects. Therefore, adaptive algorithms must be used to track the system's state. Additional challenges arise when considering the identification of multiple channels simultaneously. This thesis considers different aspects of systems identification of time-variant acoustic systems in a joint framework for diverse scenarios. Alle Interessierten sind herzlich eingeladen, eine Anmeldung ist nicht erforderlich. -- Irina Esser 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/

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Communication Technology Colloquium at IKS
by Irina Esser 14 Jan '22

14 Jan '22

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquium. *Friday, January 21, 2022* *Speaker*: Ali Yilmaz Yildirim *Time*: 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master Lecture*: Dynamic Spectrum Access in Highly Mobile Environments Dynamic Spectrum Access (DSA) has been introduced to enable the opportunistic utilization of licensed frequency bands by secondary users (SUs). DSA was introduced for ground-based users, and algorithms were developed by considering those users. With the increase in air data traffic, DSA has started to be considered for airborne communication. Nevertheless developed algorithms for ground-based users can not be reused for airborne communication. The main reason for that is the high mobility of aerial vehicles. Therefore, current DSA algorithms should be examined and adapted for highly mobile environments. With this need, this thesis aims to develop algorithms for DSA in highly mobile environments by focusing on the aspects of DSA that require to be adapted. As a result of SUs being considered as temporary users, SUs should vacate the channel with the transmission of the primary users (PUs) and find a new common idle channel to continue their communication. With the highly varying spectral environment as a result of high mobility, communication between SUs will be interrupted with PU transmission more frequently compared to stationary environments. That is why SUs should detect PU transmission and react by finding a new common idle channel in the shortest time. By considering the need for an adaptation in this aspect of DSA, this thesis proposes algorithms and a frame structure to identify the PU presence and to find a new common channel in highly mobile environments. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of dates of the Communication Technology Colloquium can be found at: http://www.iks.rwth-aachen.de/aktuelles/kolloquium -- Irina Esser 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/

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Coomunication Technology Colloquium at IKS
by Irina Esser 17 Nov '21

17 Nov '21

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquium. *Wednesday, November 24, 2021* *Speaker*: Georg Krekel *Time*: 2:00 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Bachelor Lecture*: Comparison of Sound Field Translation Methods Higher Order Ambisonics (HOA) signals can be used to allow directional playback of sound signals, where the listener can rotate their head around all three rotational axis. HOA signals can also be adapted to allow translational movement of the listener using sound field translation. Sound field translation is the process of evaluating a sound field at a different position than it was recorded at. At the IKS (Institute of Communication Systems, RWTH Aachen) multiple algorithms have been proposed, that try to achieve psychoacoustically plausible sound field translation, however the inner workings of these algorithms are not well understood. This thesis compares different aspects of two algorithms, Adaptive Beamforming and Adaptive Spacewarping, mainly by deriving analytical expressions that allow deeper understanding of the underlying effects. The algorithms were split into two main stages, the translation stage and the filtering stage. There are significant differences between ASW and ABF. In the translation stage ASW is distorted compared to ABF. However, differences shrink with the order of the HOA input signal. The filtering stage for ABF and ASW is very similar, especially if oracle information of covariance matrices is not available. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of dates of the Communication Technology Colloquium can be found at: http://www.iks.rwth-aachen.de/aktuelles/kolloquium -- Irina Esser 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/

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Kommunikationstechnisches Kolloquium am IKS
by Irina Ronkartz 06 Oct '21

06 Oct '21

Sehr geehrte Abonnenten des Kolloquium-Newsletters, gerne informieren wir Sie über den nächsten Termin unserer Kommunikationstechnischen Kolloquiums. *Dienstag, 12.10.2021* *Vortragender:* Henning Konermann *Zeit: *11:00 Uhr *Ort*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Bachelor-Vortrag*: Modellbasiertes 3D Headtracking zur Anwendung in adaptiven Übersprechkompensationssystemen In adaptiven Übersprechkompensationssystemen werden verlässliche 3D Positions- und Orientierungsdaten eines Zuhörers in Echtzeit benötigt. Für die Bestimmung dieser Daten wird meist ein zusätzliches physisches Messsystem installiert. Eine Vermeidung dieses Aufbaus hat erhebliche Kosten- und Aufwandsvorteile. Durch das Schätzen der Laufzeit aus den in adaptiven Übersprechkompensationssystemen verwendeten kopfbezogenen Impulsantworten kann anhand eines geometrischen Ansatzes Headtracking betrieben werden. Die Literatur zeigt, dass mit zusätzlichen physischen Messsystemen geometrisch basiertes 2D und 3D Headtracking möglich ist. Außerdem wurde gezeigt, dass für den 2D Fall ohne zusätzliches Messsystem ein modellbasierter Ansatz einem geometrischen Ansatz überlegen ist. Ziel dieser Arbeit ist die Erstellung und Realisierung eines Modells, welches den modellbasierten Ansatz auf den 3D Fall erweitert. Bei der Erstellung eines durchschnittlichen Modells sowie individualisierter Modelle werden kopfbezogene Übertragungsfunktionen verwendet. Das Tracking erfolgt durch die Minimierung eines aus der Literatur adaptierten Optimierungsproblems. Im Anschluss werden Experimente simuliert. Die Trackinggenauigkeit verschieden stark personalisierter Modelle wird mit einem geometrischen Ansatz verglichen. In den meisten Anwendungsfällen lässt sich die Überlegenheit des Modells feststellen. Weiterhin wird erkannt, dass das Modell durch Orientierungslimitierungen einzuschränken ist, um sinnvolle Ergebnisse zu erzielen. Alle Interessierten sind herzlich eingeladen, eine Anmeldung ist nicht erforderlich. Allgemeine Informationen zum Kolloquium sowie eine aktuelle Liste der Termine des Kommunikationstechnischen Kolloquiums finden Sie unter: 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/

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Communication Technology Colloquium at IKS
by Irina Ronkartz 01 Oct '21

01 Oct '21

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquium. *Friday, October 8, 2021* *Speaker:* Frederick Pietschmann *Time:* 10:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Bachelor Lecture*: Model-Based Algorithms for Retrospective Individualization of Binaural Signals With binaural signals, it is possible to capture the sensation of spatial hearing that humans are used to from real-life auditory scenes. However, because binaural recordings are always individualized for a speciﬁc target person, the authenticity of a binaural recording is perceived differently by different listeners. It is therefore desirable that a binaural recording is always individualized for the respective listener. In this thesis, the existing Binaural Cue Adaptation (BCA) system from the Institute of Communication Systems is adjusted and reinterpreted for it to be able to retrospectively individualize an existing binaural signal for a new target person. Existing approaches to the main components of the BCA system, the Localization block and the Modiﬁcation block, are reviewed and analyzed and multiple new concepts and ideas are introduced and algebraically described: New optimization target functions, a concept for joint optimization over multiple frequencies and multiple approaches that attempt to lessen the impact of artifacts which may occur due to model mismatches and / or erroneous location estimates. A theoretical evaluation is conducted in which the localization performance of both existing and new approaches is benchmarked. The results conﬁrm that some of the newly proposed ideas and concepts improve the overall performance of the BCA system. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of 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/

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Communication Technology Colloquium at IKS
by Irina Ronkartz 17 Sep '21

17 Sep '21

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquium at IKS. *Friday, September 24, 2021* *Speaker:* Frederik Blang *T**ime:* 2:00 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: Speech Enhancement for Active Occlusion Cancellation on Noisy Environments The natural perception of one's own voice while wearing a headset is increasingly in the focus of customers and manufacturers. Due to the occlusion effect which occurs when the ear canal is blocked, body-conducted sound is amplified, resulting in an unpleasant sound of the own voice. It becomes difficult to control the volume of one's own voice leading to earlier vocal fatigue. Active Occlusion Cancellation (AOC) aims to suppress this effect and can be combined with a hear-through system for a natural own-voice perception. In noisy environments, for example call centers, it is desirable to only equalize the own voice. Some business headsets already provide a sidetone which uses a boom microphone to record the own voice, however this signal often isn't equalized. This thesis develops a real-time system which provides a natural own-voice perception for the user of a headset using the boom microphone. Besides the implementation of a filter for the direct sound, also the room reverberation of one's own voice is estimated using convolution. Algorithmic room simulation on a DSP is considered, but ultimately rejected due to memory card. The low-latency filtering of the direct sound is performed on the DSP, while the longer room filters are run on the PC. Evaluations using simulations and measurements show the direct-path filter to perform well, while the room filters can't provide a natural estimation of the room sound. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of dates of the Communication Technology Colloquium can be found at https://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/

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Communication Technology Colloquium at IKS
by Irina Ronkartz 09 Sep '21

09 Sep '21

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquium. *Thursday, September 16, 2021* *Speaker:* Vlerar Shala *Time:* 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: AI-Based Optimization of Pulse Shaped OTFS for Vehicular Communication Future vehicular communication systems require a reliable communication to enable connected and automated driving. Vehicular channels are considered to be truly doubly-dispersive channels, i.e., strongly varying in both time and frequency. However, the performance of the traditional wireless communication systems operating under doubly-dispersive channels degrades significantly. Orthogonal time frequency and space (OTFS) is a recently proposed modulation scheme designed to be robust against doubly-dispersive channels. OTFS is a new and novel two-dimensional (2D) pulse-shaped modulation scheme designed in the delay-Doppler (DD) domain and promises significant improvements on the physical layer. OTFS is a combination of classical Gabor signaling with a unique time-frequency (TF) spreading. Data symbols are located in the DD domain and spread over the entire TF domain using the symplectic finite Fourier transform (SFFT). The TF spreading accounts in a linear fashion for the doubly dispersive nature of time-variant multi-path channel. The TF spreading is also referred to as OTFS transform and the Gabor transform as the Heisenberg transform. However, OTFS requires proper channel information and the use of appropriated equalizers to exploit the full spreading gain. Doubly-dispersive channels are characterized by their spreading region spanned by two times max, and max, corresponding to the maximum Doppler shift and delay spread. To mitigate the strong interference between different TF slots, TF grid and pulses should “match” the DD spreading region of the doubly-dispersive channel, typically determined on a longer time scale-like. This approach is known as pulse and grid matching rule. In this thesis, we use the so-called mobility modes with distinct grid and pulses to follow the pulse and grid matching rule. However, mobility modes control the interference on a coarse level because they cannot match the pulse and grid matching rule completely. The remaining interference is accounted by the implemented mean square error (MMSE) linear equalizer, which is tuned for each frame. We implement the OTFS transceiver based on a polyphase implementation for orthogonalized Gaussian pulses and evaluate mobility modes with doubly-dispersive vehicular channels generated by the QuaDRiGa channel simulator. For practical implementation, the performance of mobility modes should be predicted and then the mobility mode with the best performance is selected to send the next frame. However, the prediction of mobility modes requires the prediction of the channel itself. In this thesis, we propose a novel method to predict the channel by predicting the spreading function which represents the channel in the DD domain. We propose to predict the spreading function using a new variant of Long Short-Term Memory (LSTM) neural networks known as Convolutional LSTM. The architecture of Convolutional LSTM is both recurrent and convolutional which enables it to capture the spatiotemporal correlation of the data and utilize it for the prediction. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of 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/

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Communication Technology Colloquium at IKS
by Irina Ronkartz 02 Sep '21

02 Sep '21

Dear subscribers of the colloquium newsletter, we are happy to inform you about the next date of our Communication Technology Colloquiums. *Friday, September 10, 2021* *Speaker:* Rocio Martin Lima *Time:* 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master Lecture:* Optimized Receiver Systems Preserving Maximum Relevant Mutual Information In modern communication systems the receiver-sided signal processing often results in bottlenecks. In particular, high-speed computations in channel decoders are demanding, but also crucial to achieve high data rates. Therefore, reduced complexity decoding algorithms for the widely used low-density parity-check (LDPC) codes are developed in this thesis. State-of-the-art LDPC decoders use costly mathematical operations and high-precision log-likelihood ratios in iterative message passing algorithms. Both typically results in high decoder complexity. In contrast, this thesis proposes to design check node operations that decode directly using the bit-level representation of strongly quantized integer messages. Like this, small logical circuits that only use simple bit-level operations (e.g. XOR) on the passed messages can replace demanding check node operations. At the same time, only a small number of bits per message is required. An information bottleneck inspired design method is applied to learn suitable logical circuits for decoding. This method involves genetic optimization algorithms. All interested parties are cordially invited, registration is not required. General information on the colloquium, as well as a current list of dates of the Communication Technology Colloquium can be found at: https://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/

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Communication Technology Colloquim at IKS
by Irina Ronkartz 09 Jul '21

09 Jul '21

Dear subscribers of the colloquium newsletter, we are pleased to announce the next dates of our Communication Technology Colloquium. *Monday, July 19, 2021* *Speaker:* Jonas Förster *Time*: 2:30 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: Multi-Channel Filter Design for Headphones with Active Noise Cancelling Active noise cancellation (ANC) headphones became increasingly popular during the last decade. They are especially capable of reducing low-frequent noise, where the passive isolation of headphones is ineffective. Nowadays, commercial ANC headphones mostly use a single reference microphone. This limits the maximum achievable active attenuation. Adding multiple reference microphones to headphones can overcome these limitations by exploiting the spatial characteristics of the incoming noise. This thesis presents two different multi-channel filter strategies for feedforward ANC in headphones. On the one hand, a time-invariant filter for reducing diffuse noise and on the other hand a time-variant filter structure for reducing directional non-stationary noise are presented. Additionally, a commercial ANC headphone is extended by multiple reference microphones and the increase in active attenuation based on the microphone positions is evaluated. The results indicate that both filter techniques can improve the achievable active attenuation for their dedicated use cases. Furthermore, the active attenuation can be improved by additional microphones if they are placed on the side of the corresponding loudspeaker. and *Monday, July 19, 2021* *Speaker: *Zhi Li *Time:* 3:15 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture:* Real-Time Rendering of Recorded Spatial Audio Content for Moving Listeners All intersted parties are coridally invited, registration is not required. General information about the colloquium as well as a current time scale of the Communication Technology Colloquium can be found at: https://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/

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Communication Technology Colloquim at IKS
by Irina Ronkartz 02 Jul '21

02 Jul '21

Dear subscribers of the colloquium newsletter, we are pleased to announce the next date of our Communication Technology Colloquium: *Friday, July 9, 2021* *Speaker:* Marc Mittag *Time:* 3:30 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: Deep Speech Inpainting for Masks Resulting from Noisy Spectra Speech enhancement belongs to the domain of noise detection, estimation and reductionwith the goal of increasing speech quality and intelligibility for speech signals subject toenvironmental noise. However, conventional methods typically insufficiently remove noisein challenging low-SNRnon-stationary noise environments. In this thesis, we explore a twostage speech enhancement method utilizing the strengths of machine learning and deep speechinpainting for these difficult scenarios. Consisting out of a masking and inpainting stage,we deploy two powerful residualCNNs in an encoder-decoder structure, one for each stage.The purpose of the first stage is to mask a noisy-speech magnitude spectrogram using binarymasking such that it sufficiently removes noise but retains most of the important speechinformation. The second stage deals with reconstruction of the previously removedT-Fpointswith the goal of creating a corruption-free, continuous clean-speech signal. The results showthat our approach outperforms conventional speech enhancement methods and achieves similarstate-of-the-art performance regarding other speech inpainting studies. Compared to thenoisy-speech signal, our approach achieves up to 3 times higherPESQscores and substantialSNRimprovements of several decibels on ideal conditions. Furthermore, we demonstrate thatthe inpainting neural network can inpaint even highly masked speech if specifically trained for. All interested parties are cordially invited, registration is not required. General information about the colloquium as well as a current time scale of the Communication Technology Colloquium can be found at: https://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/

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