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Communication Technology Colloquium at IKS

von Irina Ronkartz

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/

2 Jahre, 7 Monate

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Communication Technology Colloquium at IKS

von Irina Ronkartz

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/

2 Jahre, 7 Monate

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Communication Technology Colloquium at IKS

von Irina Ronkartz

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/

2 Jahre, 8 Monate

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Communication Technology Colloquim at IKS

von Irina Ronkartz

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/

2 Jahre, 9 Monate

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Communication Technology Colloquim at IKS

von Irina Ronkartz

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/

2 Jahre, 10 Monate

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Communication Technology Colloquium at IKS

von Irina Ronkartz

Dear subscribers of the colloquium newsletter, we are pleased to announce the next date of our Communication Technology Colloquium: *Wednesday, June 23, 2021* *Speaker:* Markus Tilichi *Tim*e: 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: Enhanced Own Voice Perception for Hearables Using Machine Learning Modern headphones implement sophisticated signal processing and control algorithms to improve the user’s hearing and listening experience. Especially new generation in-ear headphones, so-called hearables, integrate these technologies, such as active noise control, on a large scale. A remaining issue with hearables is the sound degradation introduced through sealing the ear canal. This degradation is called the Occlusion Effect. It is often described as boomy and hollow perception of the speaker’s own voice. While Active Noise Cancellation reduces ambient noise, the Occlusion Effect still persists. In order to improve the speaker’s own voice perception and alleviate the Occlusion Effect, it is required to play back some of the voice signal without amplifying ambient noise. In this thesis a novel approach for selective hear-through based on deep neural networks is investigated. Integrated into a feed-forward ANC topology the proposed neural network utilizes ambient and in-ear microphone signals for an estimation of the speaker’s own voice. Speech samples for both microphone signals were simulated through augmentation of the DARPA TIMIT speech corpus. This included virtually occluding the samples for one channel and adding real-world noise samples to the other. The proposed network was found to reduce ambient noise from the test dataset to a barely audible extent. Metrics for quality and intelligibility suggest superior denoising performance in comparison with one channel network benchmarks. Despite the relatively small training dataset, the network may also regularize well when trained with measurement data. 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/atktuelles/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/

2 Jahre, 10 Monate

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Communication Technology Colloquium at IKS

von Irina Ronkartz

Dear subscribers of the colloquium newsletter, we are pleased to announce the next date of our Communication Technology Colloquium: *Monday, June 21, 2021* *Speaker:* Henning Niendieck *Time:* 2:00 p.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Lecture*: Optimized Design of an Acoustic Front-End for Active Noise Cancelling Headphones Headphones with active noise cancelling (ANC) capability become more and more common in everyday life. The acoustic front-end, consisting of the headphone enclosure, a speaker and at least two microphones, is a crucial part of the ANC system. It significantly influences the achievable degree of noise cancelling. The optimization of the acoustic front-end is therefore a key factor for a high ANC performance. Being able to completely predict the influence of every element of the acoustic front-end is a desirable goal. This work comprises an investigation of the different components of the acoustic front-end. It includes the characterization of a set of microphones to evaluate the influence on the ANC performance. A development of a model of the electro-acoustic system of a headphone enclosure with an integrated dynamic speaker allows the simulation of relevant transfer paths. Every individual element of the enclosure is modeled, so that the effect of every parameter on the transfer paths can be investigated. This provides a great advantage over investigations on the basis of measurements. A comparison of the boundary element method and lumped element method shows their suitability for acoustic modeling. The inability of the used implementation of the boundary element method to directly model viscothermal losses exhibits limitations, as these losses play an important role in the acoustic front-end. A 3D print of the prototype allowed the verification of the acoustic model with measurements. The different enclosure design parameters with regard to ANC performance were studied on the bases of both, simulations and measurement. An improvement of the prototype could be achieved by damping resonances. This reduces group delay in the path between the speaker and the inner microphone, which is an important limiting factor for ANC. The group delay of the inner microphone was found to be significant for low frequencies. The investigations deliver valuable knowledge about the influence of the different parameters of the acoustic front-end on the important factors for ANC. An acoustic model was obtained that allows the prediction of various transfer paths and an easy fine tuning of the elements of the acoustic front-end. 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/

2 Jahre, 10 Monate

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Communication Technology Colloquium at IKS

von Irina Ronkartz

Dear subscribers of the colloquium newsletter, we are pleased to announce the next date of our Communication Technology Colloquium: *Thursday, June 17, 2021* *Speaker*: Daniel Gotzens *Time*: 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Bachelor Lecture*: Real-Time Own Voice Estimation for Hearables Utilizing Multiple Microphone Signals Hearable devices employ several microphones to be used in telecommunication applications as well as for active noice cancellation. It is proposed that the signals generated by these microphones can be combined into an accurate and low-interference estimate of the user's own voice in real time by using digital beamforming algorithms, namely the so-called delay-and-sum and minimum variance distortionless response beamformers, especially in conjunction with additional filtering in the shape of a bandpass or a Wiener filter. To test this, several input samples are recorded on a hearable device and then processed with said algorithms. It is found that it is indeed possible to generate such a signal using the proposed algorithms, improving the signal to noise ratio by several decibels while maintaining a low distortion of the speech signal. 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/

2 Jahre, 10 Monate

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Kommunikationstechnisches Kolloquium am IKS

von Irina Ronkartz

Sehr geehrte Abonnenten des Kolloquium-Newsletters, gerne informieren wir Sie über den nächsten Termin unseres Kommunikationstechnischen Kolloquiums. *Montag, 3. Mai 2021* *Vortragender*: Yannick Fleischmann *Zeit:* 14:00 Uhr *Ort*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master-Vortrag*: Nachbildung von Körperschall in Ohrsimulatoren Das tragen von Ohrhörern oder Hörgeräten führt durch den Verschluss des Ohrkanals zu einer veränderten Stimmwahrnehmung. Diese wird hervorgerufen durch die Einstrahlung von Körperschall durch die Ohrkanalwände. Stetig zunehmende Rechenleistung in immer kleineren Formaten ermöglicht immer komplexere Methoden zur aktiven Störgeräuschunterdrückung, so auch zur Reduktion des beschriebenen Effektes. Um solche Systeme testen zu können sind standardisierte Messmethoden nötig, die für Körperschall nicht existieren. Im Rahmen dieser Arbeit werden verschiedene Methoden untersucht, mit denen Körperschall in Ohrsimulatoren simulierbar gemacht werden kann. Zwei verschiedene Schallwandlerarten werden im Hinblick auf ihre Eignung hierfür untersucht. Hierzu werden akustische Messungen an einem vereinfachten Ohrkanalmodell gemacht. Aus den Ergebnissen werden Empfehlungen für die Erweiterung bestehender Ohrsimulatoren abgeleitet. 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: 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/

3 Jahre

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Communication Technology Colloquium at IKS

von Irina Ronkartz

Dear subscribers of the colloquium newsletter, we are pleased to announce the next date for our Communication Technology Colloquium: *Wednesday, April 21, 2021* *Speaker*: Irina Kharlamova *Time*: 11:00 a.m. *Location*: https://rwth.zoom.us/j/97904157921?pwd=SWpsbDl0MWhrWjY1ZkZaeFRoYmErZz09 Meeting-ID: 979 0415 7921 Passwort: 481650 *Master Lectur*e: Primary-Ambient Aware Sound Field Translation Sound field translation is a technique that allows the sound field to be represented in a displaced coordinate system. This master's thesis presents a coherence-adaptive method of sound field translation based on space warping techniques. The proposed method moves mainly only the direct part of the signal and keeps the ambient part relatively unchanged. The system first identifies the direct and ambient components of the signal and then uses this data to build a filter-mask. For the first task, the method uses parametric decomposition of the sound field. A series of experiments have been conducted with single and multiple sources presented as directional noise or speech, also including reverberation. In experiments comparing other different translation methods, the proposed coherence-adaptive approach achieves excellent performance in terms of various instrumental metrics. 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/

3 Jahre

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