Jürgen Peissig - Academia.edu (original) (raw)

Papers by Jürgen Peissig

Acta Acustica

Perceived externalization is a relevant feature to create an immersive acoustic environment with ... more Perceived externalization is a relevant feature to create an immersive acoustic environment with headphone reproduction. In the present study, listener-specific acoustic transfer characteristics for an azimuth angle of 90° were modified to investigate the role of monaural spectral cues, interaural level differences (ILDs), and temporal fluctuations of ILDs on perceived externalization in anechoic and reverberant environments. Listeners’ ratings suggested that each acoustic cue was important for perceived externalization. If only one correct acoustic cue remained in the ear signals, the sound image could not be perceived as fully externalized. Reverberation did reduce but not eliminate the influences of monaural spectral and ILD cues on perceived externalization. Additionally, the spectral details of the ipsilateral ear signal were more important for perceived externalization than those in the contralateral ear signal. A computational model was proposed to quantify those relationship...

The Journal of the Acoustical Society of America

Applied Sciences

Several studies show that the reverberation and spectral details in direct sounds are two essenti... more Several studies show that the reverberation and spectral details in direct sounds are two essential cues for perceived externalization of virtual sound sources in reverberant environments. The present study investigated the role of these two cues in contralateral and ipsilateral ear signals on perceived externalization of headphone-reproduced binaural sound images at different azimuth angles. For this purpose, seven pairs of non-individual binaural room impulse responses (BRIRs) were measured at azimuth angles of −90°, −60°, −30°, 0°, 30°, 60°, and 90° in a listening room. The magnitude spectra of direct parts were smoothed, and the reverberation was removed, either in left or right ear BRIRs. Such modified BRIRs were convolved with a speech signal, and the resulting binaural sounds were presented over headphones. Subjects were asked to assess the degree of perceived externalization for the presented stimuli. The result of the subjective listening experiment revealed that the magnit...

Optics Express

In this paper we present two resource allocations techniques in a visible light communication net... more In this paper we present two resource allocations techniques in a visible light communication network with overlapping coverage areas due to the use of access points. Particularly, the first approach exploits the rate maximization criteria, and then aims at maximizing the network rate under constraints on minimum and maximum rates, while the other procedure focuses on achieving fairness in the rate of each user accessing the network. The proposed system relays on optical code division multiple access mechanism, and resource allocation is intended in terms of codes assigned to a given user. Simulation results have been addressed in terms of achievable data rates, outage probability and percentage of accessing users.

EURASIP Journal on Wireless Communications and Networking

Digital Radio Mondiale (DRM) is the universally, openly standardized digital broadcasting system ... more Digital Radio Mondiale (DRM) is the universally, openly standardized digital broadcasting system for all frequencies including LW, MW, and SW as well as VHF bands. Alongside providing high audio quality to listeners, DRM satisfies technological requirements posed by broadcasters, manufacturers and regulatory authorities and thus bears a great potential for the future of global radio. One of the key issues here concerns green broadcasting. Facing the need for high-power transmitters to cover wide areas, there is room for improvement concerning the power efficiency of DRM-transmitters. A major drawback of DRM is its high peak-to-average power ratio (PAPR) due to the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM), which results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. To overcome this, numerous schemes have been investigated for reducing PAPR in OFDM systems. In this paper, we review and analyze various technologies to reduce PAPR providing that the technical feasibility and DRM-specific system architecture and edge conditions regarding the system performance in terms of modulation error rate, compliance with frequency mask, and synchronization efficiency are ensured. All evaluations are carried out with I/Q signals which are monitored in real operation to present the actual performance of proposed PAPR techniques. Subsequently, the capability of the best approach is evaluated via measurements on a DRM test platform, where achieved transmit power gain of 10 dB is shown. According to our evaluation results, PAPR reduction schemes based on active constellation extension followed by a filter prove to be promising towards practical realization of power-efficient transmitters.

Lecture Notes in Computer Science, 2016

EURASIP Journal on Advances in Signal Processing, 2014

For future communication systems, filter bank multicarrier schemes offer the flexibility to incre... more For future communication systems, filter bank multicarrier schemes offer the flexibility to increase spectrum utilization in heterogeneous wireless environments by good separation of signals in the frequency domain. To fully exploit this property for frame detection and synchronization, the advantage of the filter bank should be taken at the receiver side. In this work, the concept of frequency domain processing for frame detection and synchronization is analyzed and a suitable preamble design as well as corresponding estimation algorithms is discussed. The theoretical performance of the detection and estimation schemes is derived and compared with simulation-based assessments. The results show that, even though the frequency domain algorithms are sensitive to carrier frequency offsets, satisfactory frame detection and synchronization can be achieved in the frequency domain. In comparison to time domain synchronization methods, the computational complexity increases; however, enhanced robustness in shared spectrum access scenarios is gained in case the described frequency domain approach is utilized. by introducing a prefiltering stage, and its complexity increases.

2015 23rd European Signal Processing Conference (EUSIPCO), 2015

Theory predicts a gain in transmission performance, when adapting pulse shapes of Offset Quadratu... more Theory predicts a gain in transmission performance, when adapting pulse shapes of Offset Quadrature Amplitude Modulation (OQAM) Orthogonal Frequency Division Multiplexing (OFDM) systems to delay and Doppler spread in doublydispersive channels. Here we investigate the quantitative gains in reconstruction quality and bit error rate (BER) with respect to subcarrier spacing and channel properties. It is shown that it is possible to reduce the uncoded BER by a factor of more than two and the coded BER by a factor of at least four, utilizing only two different pulse shapes. The simulation results show that channel adaptive pulse shaping for OQAM-OFDM systems is a promising concept for future mobile communication systems.

In this contribution, a carrier frequency offset (CFO) estimator for OQAM-OFDM systems based on t... more In this contribution, a carrier frequency offset (CFO) estimator for OQAM-OFDM systems based on the conjugate symmetry property of a properly designed synchronization sequence is proposed. It extends the concept of a previously described symbol-timing and phase offset recovery scheme to build a complete time-domain synchronization method. The outcome of numerical evaluations shows that the proposed CFO estimation algorithm is suitable as a coarse CFO correction for continuous stream transmission systems. It delivers satisfying results in case of AWGN channels as well as for channels with moderate delay spreads while exhibiting the drawback of a high sensitivity to symbol timing errors. Furthermore, the possibility to reduce the overhead of the synchronization sequence by allowing a certain amount of self-interference is investigated.

2012 IEEE International Symposium on Dynamic Spectrum Access Networks, 2012

In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. T... more In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. The study includes a proposal for an appropriate system design as well as a discussion on the LTE system's self-configurability to avoid potential interference to other systems when the resource allocation is made flexible. This is evaluated in terms of achievable PHY-layer throughput and block error rates (BLER) in coexistence scenarios with digital terrestrial TV (DTT) and wireless microphones (WM). Furthermore, the study makes exclusive comparisons between the current LTE PHY interface of cyclic-prefix OFDM (CP-OFDM) and one of its alternatives, the offset-QAM OFDM (OQAM-OFDM) scheme. Therefore, the aspects of interference robustness, system flexibility and complexity issues are considered. The main outcome of this study is that an LTE system based on OQAM-OFDM offers higher data rates and conforms better to potential regulatory rules than the current CP-OFDM implementation. The OQAM-OFDM scheme is significantly more robust and delivers higher data rates, in particular for the coexistence with narrow-band services. Finally, through the complexity analysis, we conclude that such performance-complexity trade-off may be reasonable in the future as the overall system complexity of OQAM-ODFM is only incremental.

2014 IEEE 10th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2014

ABSTRACT In this contribution, a direct comparison of the Offset-QAM-OFDM (OQAM-OFDM) and the Cyc... more ABSTRACT In this contribution, a direct comparison of the Offset-QAM-OFDM (OQAM-OFDM) and the Cyclic Prefix OFDM (CP-OFDM) scheme is given for an 802.11a based system. Therefore, the chosen algorithms and choices of design are described and evaluated as a whole system in terms of bit and frame error rate (BER/FER) performance as well as spectral efficiency and complexity in the presence of multipath propagation for different modulation orders. The results show that the OQAM-OFDM scheme exhibits similar BER and FER performance at a 24% higher spectral efficiency and achievable throughput at the cost of an up to five times increased computational complexity.

2013 IEEE International Conference on Communications (ICC), 2013

In this contribution the influence of different broadband OFDM schemes on the perceptual audio qu... more In this contribution the influence of different broadband OFDM schemes on the perceptual audio quality of narrowband wireless microphone links is evaluated, since coexistence scenarios of wireless microphones and Orthogonal frequencydivision multiplexing (OFDM) based services arise in the TV bands. Therefore, we present different non-contiguous cyclicprefix (CP-)OFDM and offset quadrature amplitude modulation (OQAM-)OFDM system designs based on the spectrum pooling concept. We measure their power suppression in the subchannel allocated for the wireless microphone. As an indicator of the perceptual audio quality, we measure the objective difference grade of a colored noise audio signal emitted over a consumerlike hardware. The measurements show that the non-contiguous OQAM-OFDM scheme not only introduces lower interference to the FM link, but also has the advantage of requiring less number of notched carriers in comparison to CP-OFDM. By application of non-contiguous OQAM-OFDM with an appropriate number of notched carriers instead of the classical CP-OFDM scheme, wireless microphone systems can still sustain a significant low SIR when non-professional hardware is applied.

Frequenz, 2012

Equalization of broadband signals can be efficiently realized in frequency domain. One prominent ... more Equalization of broadband signals can be efficiently realized in frequency domain. One prominent example is the orthogonal frequency division multiplexing (OFDM) transmission technique. With the introduction of a cyclic prefix and a modulation onto orthogonal subcarriers the equalization can be performed in frequency domain with one tap only. However the extremely high peak to average power ratio of OFDM modulated transmit signals and the demand of linearity inside the signal transmission chain results in a poor energy efficiency at the power amplifier. This paper claims, that as long as a cyclic prefix exists, any receive signal can be equalized in frequency domain.In this paper a transmission scheme with constant envelope is chosen for energy efficiency reasons. Therefore an FSK modulation and gaussian pulse shaping is used to create the transmit signal. Equalization at the receiver is done in frequency domain as known in OFDM. To simplify the equalization, a cyclic prefix is adde...

2014 International Conference on Advanced Technologies for Communications (ATC 2014), 2014

The Journal of the Acoustical Society of America, 1997

Speech reception thresholds (SRTs) were obtained for different azimuths of up to three interferin... more Speech reception thresholds (SRTs) were obtained for different azimuths of up to three interfering sound sources in a simulated ("virtual") spatial arrangement. For the SRT measurements a fast subjective threshold assessment method was used. The reduction in SRT relative to the reference threshold caused by spatial separation of target and interference signal is called the intelligibility level difference (ILD). For normal listeners, the maximum ILD was achieved at 105 degrees or 255 degrees azimuth of a single noise source when the target emanated from the front (0 degree azimuth). The ILD decreased rapidly if the number of interfering signals was increased and if they were located on opposite sides of the head. When using continuous speech as interference, this decrease of ILD was less pronounced. These findings indicate that the binaural system can suppress interference from only one azimuthal region at a time and can utilize temporal pauses in the interference to suppress a second interference from a different direction. For eight sensorineural impaired listeners, the maximum attainable ILD for one interfering noise source was reduced in a way not predictable from the audiogram. The ability to exploit pauses in the signal of an interfering talker was also reduced. Hence, hearing-impaired listeners are handicapped in realistic spatial interference situations both by an increased monaural SRT and a reduced binaural noise reduction ability.

The Journal of the Acoustical Society of America, 2012

Noise can be disturbing, stressful or even harmful. Headphones with active noise cancellation (AN... more Noise can be disturbing, stressful or even harmful. Headphones with active noise cancellation (ANC) can enhance the user's comfort, especially when travelling. On a plane or a train, in the street or at work, these headphones give the possibility to reduce unwanted noise. The range of ANC headphones on the market is constantly increasing. Circumaural and supra-aural headphones with different control strategies have been available for a long time; over the last few years the product lines have been expanded to in-ear headphones. These headphones already have quite a good passive attenuation and are equipped with feedforward control for active noise cancellation. The best results in attenuation are achieved by semi-adaptive digital controls, which choose the best filter depending on the noise spectrum and can be manually adapted to the user. A fully adaptive control has already been proven to be very effective in aviation headsets and other ANC applications. Besides the market analysis of ANC headphones we would like to present an adaptive feedforward control for in-ear headphones and highlight the advantages compared to a static feedforward control.

The Journal of the Acoustical Society of America, 2012

Acta Acustica united …, 1997

... Wittkop et al.: Speech Processing for Hearing Aids 689 ... That is, the target estimate will ... more ... Wittkop et al.: Speech Processing for Hearing Aids 689 ... That is, the target estimate will be mainly driven by the input data ifthe input signal-to-noise ratio (SIN) is high (ie, when the preliminary estimators yield high "confidence"), and will be the "best guess" the system can make ...

EURASIP Journal on Advances in Signal Processing, 2014

For future communication systems, filter bank multicarrier schemes offer the flexibility to incre... more For future communication systems, filter bank multicarrier schemes offer the flexibility to increase spectrum utilization in heterogeneous wireless environments by good separation of signals in the frequency domain. To fully exploit this property for frame detection and synchronization, the advantage of the filter bank should be taken at the receiver side. In this work, the concept of frequency domain processing for frame detection and synchronization is analyzed and a suitable preamble design as well as corresponding estimation algorithms is discussed. The theoretical performance of the detection and estimation schemes is derived and compared with simulation-based assessments. The results show that, even though the frequency domain algorithms are sensitive to carrier frequency offsets, satisfactory frame detection and synchronization can be achieved in the frequency domain. In comparison to time domain synchronization methods, the computational complexity increases; however, enhanced robustness in shared spectrum access scenarios is gained in case the described frequency domain approach is utilized. by introducing a prefiltering stage, and its complexity increases.

Acta Acustica

Perceived externalization is a relevant feature to create an immersive acoustic environment with ... more Perceived externalization is a relevant feature to create an immersive acoustic environment with headphone reproduction. In the present study, listener-specific acoustic transfer characteristics for an azimuth angle of 90° were modified to investigate the role of monaural spectral cues, interaural level differences (ILDs), and temporal fluctuations of ILDs on perceived externalization in anechoic and reverberant environments. Listeners’ ratings suggested that each acoustic cue was important for perceived externalization. If only one correct acoustic cue remained in the ear signals, the sound image could not be perceived as fully externalized. Reverberation did reduce but not eliminate the influences of monaural spectral and ILD cues on perceived externalization. Additionally, the spectral details of the ipsilateral ear signal were more important for perceived externalization than those in the contralateral ear signal. A computational model was proposed to quantify those relationship...

The Journal of the Acoustical Society of America

Applied Sciences

Several studies show that the reverberation and spectral details in direct sounds are two essenti... more Several studies show that the reverberation and spectral details in direct sounds are two essential cues for perceived externalization of virtual sound sources in reverberant environments. The present study investigated the role of these two cues in contralateral and ipsilateral ear signals on perceived externalization of headphone-reproduced binaural sound images at different azimuth angles. For this purpose, seven pairs of non-individual binaural room impulse responses (BRIRs) were measured at azimuth angles of −90°, −60°, −30°, 0°, 30°, 60°, and 90° in a listening room. The magnitude spectra of direct parts were smoothed, and the reverberation was removed, either in left or right ear BRIRs. Such modified BRIRs were convolved with a speech signal, and the resulting binaural sounds were presented over headphones. Subjects were asked to assess the degree of perceived externalization for the presented stimuli. The result of the subjective listening experiment revealed that the magnit...

Optics Express

In this paper we present two resource allocations techniques in a visible light communication net... more In this paper we present two resource allocations techniques in a visible light communication network with overlapping coverage areas due to the use of access points. Particularly, the first approach exploits the rate maximization criteria, and then aims at maximizing the network rate under constraints on minimum and maximum rates, while the other procedure focuses on achieving fairness in the rate of each user accessing the network. The proposed system relays on optical code division multiple access mechanism, and resource allocation is intended in terms of codes assigned to a given user. Simulation results have been addressed in terms of achievable data rates, outage probability and percentage of accessing users.

EURASIP Journal on Wireless Communications and Networking

Digital Radio Mondiale (DRM) is the universally, openly standardized digital broadcasting system ... more Digital Radio Mondiale (DRM) is the universally, openly standardized digital broadcasting system for all frequencies including LW, MW, and SW as well as VHF bands. Alongside providing high audio quality to listeners, DRM satisfies technological requirements posed by broadcasters, manufacturers and regulatory authorities and thus bears a great potential for the future of global radio. One of the key issues here concerns green broadcasting. Facing the need for high-power transmitters to cover wide areas, there is room for improvement concerning the power efficiency of DRM-transmitters. A major drawback of DRM is its high peak-to-average power ratio (PAPR) due to the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM), which results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. To overcome this, numerous schemes have been investigated for reducing PAPR in OFDM systems. In this paper, we review and analyze various technologies to reduce PAPR providing that the technical feasibility and DRM-specific system architecture and edge conditions regarding the system performance in terms of modulation error rate, compliance with frequency mask, and synchronization efficiency are ensured. All evaluations are carried out with I/Q signals which are monitored in real operation to present the actual performance of proposed PAPR techniques. Subsequently, the capability of the best approach is evaluated via measurements on a DRM test platform, where achieved transmit power gain of 10 dB is shown. According to our evaluation results, PAPR reduction schemes based on active constellation extension followed by a filter prove to be promising towards practical realization of power-efficient transmitters.

Lecture Notes in Computer Science, 2016

EURASIP Journal on Advances in Signal Processing, 2014

For future communication systems, filter bank multicarrier schemes offer the flexibility to incre... more For future communication systems, filter bank multicarrier schemes offer the flexibility to increase spectrum utilization in heterogeneous wireless environments by good separation of signals in the frequency domain. To fully exploit this property for frame detection and synchronization, the advantage of the filter bank should be taken at the receiver side. In this work, the concept of frequency domain processing for frame detection and synchronization is analyzed and a suitable preamble design as well as corresponding estimation algorithms is discussed. The theoretical performance of the detection and estimation schemes is derived and compared with simulation-based assessments. The results show that, even though the frequency domain algorithms are sensitive to carrier frequency offsets, satisfactory frame detection and synchronization can be achieved in the frequency domain. In comparison to time domain synchronization methods, the computational complexity increases; however, enhanced robustness in shared spectrum access scenarios is gained in case the described frequency domain approach is utilized. by introducing a prefiltering stage, and its complexity increases.

2015 23rd European Signal Processing Conference (EUSIPCO), 2015

Theory predicts a gain in transmission performance, when adapting pulse shapes of Offset Quadratu... more Theory predicts a gain in transmission performance, when adapting pulse shapes of Offset Quadrature Amplitude Modulation (OQAM) Orthogonal Frequency Division Multiplexing (OFDM) systems to delay and Doppler spread in doublydispersive channels. Here we investigate the quantitative gains in reconstruction quality and bit error rate (BER) with respect to subcarrier spacing and channel properties. It is shown that it is possible to reduce the uncoded BER by a factor of more than two and the coded BER by a factor of at least four, utilizing only two different pulse shapes. The simulation results show that channel adaptive pulse shaping for OQAM-OFDM systems is a promising concept for future mobile communication systems.

In this contribution, a carrier frequency offset (CFO) estimator for OQAM-OFDM systems based on t... more In this contribution, a carrier frequency offset (CFO) estimator for OQAM-OFDM systems based on the conjugate symmetry property of a properly designed synchronization sequence is proposed. It extends the concept of a previously described symbol-timing and phase offset recovery scheme to build a complete time-domain synchronization method. The outcome of numerical evaluations shows that the proposed CFO estimation algorithm is suitable as a coarse CFO correction for continuous stream transmission systems. It delivers satisfying results in case of AWGN channels as well as for channels with moderate delay spreads while exhibiting the drawback of a high sensitivity to symbol timing errors. Furthermore, the possibility to reduce the overhead of the synchronization sequence by allowing a certain amount of self-interference is investigated.

2012 IEEE International Symposium on Dynamic Spectrum Access Networks, 2012

In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. T... more In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. The study includes a proposal for an appropriate system design as well as a discussion on the LTE system's self-configurability to avoid potential interference to other systems when the resource allocation is made flexible. This is evaluated in terms of achievable PHY-layer throughput and block error rates (BLER) in coexistence scenarios with digital terrestrial TV (DTT) and wireless microphones (WM). Furthermore, the study makes exclusive comparisons between the current LTE PHY interface of cyclic-prefix OFDM (CP-OFDM) and one of its alternatives, the offset-QAM OFDM (OQAM-OFDM) scheme. Therefore, the aspects of interference robustness, system flexibility and complexity issues are considered. The main outcome of this study is that an LTE system based on OQAM-OFDM offers higher data rates and conforms better to potential regulatory rules than the current CP-OFDM implementation. The OQAM-OFDM scheme is significantly more robust and delivers higher data rates, in particular for the coexistence with narrow-band services. Finally, through the complexity analysis, we conclude that such performance-complexity trade-off may be reasonable in the future as the overall system complexity of OQAM-ODFM is only incremental.

2014 IEEE 10th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2014

ABSTRACT In this contribution, a direct comparison of the Offset-QAM-OFDM (OQAM-OFDM) and the Cyc... more ABSTRACT In this contribution, a direct comparison of the Offset-QAM-OFDM (OQAM-OFDM) and the Cyclic Prefix OFDM (CP-OFDM) scheme is given for an 802.11a based system. Therefore, the chosen algorithms and choices of design are described and evaluated as a whole system in terms of bit and frame error rate (BER/FER) performance as well as spectral efficiency and complexity in the presence of multipath propagation for different modulation orders. The results show that the OQAM-OFDM scheme exhibits similar BER and FER performance at a 24% higher spectral efficiency and achievable throughput at the cost of an up to five times increased computational complexity.

2013 IEEE International Conference on Communications (ICC), 2013

In this contribution the influence of different broadband OFDM schemes on the perceptual audio qu... more In this contribution the influence of different broadband OFDM schemes on the perceptual audio quality of narrowband wireless microphone links is evaluated, since coexistence scenarios of wireless microphones and Orthogonal frequencydivision multiplexing (OFDM) based services arise in the TV bands. Therefore, we present different non-contiguous cyclicprefix (CP-)OFDM and offset quadrature amplitude modulation (OQAM-)OFDM system designs based on the spectrum pooling concept. We measure their power suppression in the subchannel allocated for the wireless microphone. As an indicator of the perceptual audio quality, we measure the objective difference grade of a colored noise audio signal emitted over a consumerlike hardware. The measurements show that the non-contiguous OQAM-OFDM scheme not only introduces lower interference to the FM link, but also has the advantage of requiring less number of notched carriers in comparison to CP-OFDM. By application of non-contiguous OQAM-OFDM with an appropriate number of notched carriers instead of the classical CP-OFDM scheme, wireless microphone systems can still sustain a significant low SIR when non-professional hardware is applied.

Frequenz, 2012

Equalization of broadband signals can be efficiently realized in frequency domain. One prominent ... more Equalization of broadband signals can be efficiently realized in frequency domain. One prominent example is the orthogonal frequency division multiplexing (OFDM) transmission technique. With the introduction of a cyclic prefix and a modulation onto orthogonal subcarriers the equalization can be performed in frequency domain with one tap only. However the extremely high peak to average power ratio of OFDM modulated transmit signals and the demand of linearity inside the signal transmission chain results in a poor energy efficiency at the power amplifier. This paper claims, that as long as a cyclic prefix exists, any receive signal can be equalized in frequency domain.In this paper a transmission scheme with constant envelope is chosen for energy efficiency reasons. Therefore an FSK modulation and gaussian pulse shaping is used to create the transmit signal. Equalization at the receiver is done in frequency domain as known in OFDM. To simplify the equalization, a cyclic prefix is adde...

2014 International Conference on Advanced Technologies for Communications (ATC 2014), 2014

The Journal of the Acoustical Society of America, 1997

Speech reception thresholds (SRTs) were obtained for different azimuths of up to three interferin... more Speech reception thresholds (SRTs) were obtained for different azimuths of up to three interfering sound sources in a simulated ("virtual") spatial arrangement. For the SRT measurements a fast subjective threshold assessment method was used. The reduction in SRT relative to the reference threshold caused by spatial separation of target and interference signal is called the intelligibility level difference (ILD). For normal listeners, the maximum ILD was achieved at 105 degrees or 255 degrees azimuth of a single noise source when the target emanated from the front (0 degree azimuth). The ILD decreased rapidly if the number of interfering signals was increased and if they were located on opposite sides of the head. When using continuous speech as interference, this decrease of ILD was less pronounced. These findings indicate that the binaural system can suppress interference from only one azimuthal region at a time and can utilize temporal pauses in the interference to suppress a second interference from a different direction. For eight sensorineural impaired listeners, the maximum attainable ILD for one interfering noise source was reduced in a way not predictable from the audiogram. The ability to exploit pauses in the signal of an interfering talker was also reduced. Hence, hearing-impaired listeners are handicapped in realistic spatial interference situations both by an increased monaural SRT and a reduced binaural noise reduction ability.

The Journal of the Acoustical Society of America, 2012

Noise can be disturbing, stressful or even harmful. Headphones with active noise cancellation (AN... more Noise can be disturbing, stressful or even harmful. Headphones with active noise cancellation (ANC) can enhance the user's comfort, especially when travelling. On a plane or a train, in the street or at work, these headphones give the possibility to reduce unwanted noise. The range of ANC headphones on the market is constantly increasing. Circumaural and supra-aural headphones with different control strategies have been available for a long time; over the last few years the product lines have been expanded to in-ear headphones. These headphones already have quite a good passive attenuation and are equipped with feedforward control for active noise cancellation. The best results in attenuation are achieved by semi-adaptive digital controls, which choose the best filter depending on the noise spectrum and can be manually adapted to the user. A fully adaptive control has already been proven to be very effective in aviation headsets and other ANC applications. Besides the market analysis of ANC headphones we would like to present an adaptive feedforward control for in-ear headphones and highlight the advantages compared to a static feedforward control.

The Journal of the Acoustical Society of America, 2012

Acta Acustica united …, 1997

... Wittkop et al.: Speech Processing for Hearing Aids 689 ... That is, the target estimate will ... more ... Wittkop et al.: Speech Processing for Hearing Aids 689 ... That is, the target estimate will be mainly driven by the input data ifthe input signal-to-noise ratio (SIN) is high (ie, when the preliminary estimators yield high "confidence"), and will be the "best guess" the system can make ...

EURASIP Journal on Advances in Signal Processing, 2014

For future communication systems, filter bank multicarrier schemes offer the flexibility to incre... more For future communication systems, filter bank multicarrier schemes offer the flexibility to increase spectrum utilization in heterogeneous wireless environments by good separation of signals in the frequency domain. To fully exploit this property for frame detection and synchronization, the advantage of the filter bank should be taken at the receiver side. In this work, the concept of frequency domain processing for frame detection and synchronization is analyzed and a suitable preamble design as well as corresponding estimation algorithms is discussed. The theoretical performance of the detection and estimation schemes is derived and compared with simulation-based assessments. The results show that, even though the frequency domain algorithms are sensitive to carrier frequency offsets, satisfactory frame detection and synchronization can be achieved in the frequency domain. In comparison to time domain synchronization methods, the computational complexity increases; however, enhanced robustness in shared spectrum access scenarios is gained in case the described frequency domain approach is utilized. by introducing a prefiltering stage, and its complexity increases.