A modified cepstral analysis for accurate estimation of the echo delay and the echo loss in a tel... more A modified cepstral analysis for accurate estimation of the echo delay and the echo loss in a telecommunication system is presented. It is based on the optimization of a parametric transformation of the observed signal energy spectrum. Simulation results that show the effectiveness and the accuracy of the proposed method are reported and discussed.
In the paper, the problem of assessing the speech quality provided by a real-life telephone-type ... more In the paper, the problem of assessing the speech quality provided by a real-life telephone-type network is considered. Two different approaches to the quoted problem are presented: subjective approach, based on customer surveys or trained operators, and objective approach, based on instrumental measurements of key transmission parameters. Advantages and drawbacks associated with the quoted approaches are summarised and briefly discussed. An objective approach based on an In-service Nonintrusive Measurement Device (INMD) is also presented. Finally, real life experiments, which show the effectiveness of the INMD approach are reported and discussed.
A lower bound to the accuracy of commonly adopted estimation methods for the overall conversion e... more A lower bound to the accuracy of commonly adopted estimation methods for the overall conversion error power of a sinusoidal input signal is provided in the paper. It is shown that such bound depends only on the conversion error power and is inversely proportional to the number of samples of the quantized sequence. Simulation results are reported that validate the obtained theoretical results. The provided analysis is useful for the design of estimation procedures that satisfy the accuracy requirements of the test.
Abstract—The promises of Network Functions Virtualization
(NFV) complemented with Software Define... more Abstract—The promises of Network Functions Virtualization (NFV) complemented with Software Defined Networking (SDN) can be simply stated as: get much more, pay much less. Adopting such paradigms, Service Operators expect to achieve high reductions in capital investments and greater operational agility. However, applying these concepts to existing networks will require challenging architectural updates, as well as deep changes in service models and operating procedures. To analyze such aspects, in this paper we provide an overview of the experience gathered at Italtel R&D labs in this field, and discuss state-of-the-art and future perspectives of these technologies. In particular, we describe how NFV was applied to a specific network function, the Session Border Controller, solving some related technical issues of general interest, and providing scalability and flexibility. Finally, we discuss the evolution of this virtualized network function, and its integration into an SDN-based network.
A frequency-domain approach for the estimation of ADC performance parameters is considered in the... more A frequency-domain approach for the estimation of ADC performance parameters is considered in the paper. Closed-form formulae that describe the behaviour of the proposed estimator are reported and discussed, together with simulation results that validite the theoretical analysis.
A measurement system for in-service characterization of telephone-type networks is described. It ... more A measurement system for in-service characterization of telephone-type networks is described. It is based on in-line Digital Signal Processing of the transmitted signal observed at an easily accessible test-point. The adopted techniques for the estimation of the considered parameters are summarized and discussed, together with an example of a measurement session performed on a real-life telephone-type network.
— In this paper, we analyze a real-life application of virtualization: the Italtel Virtual Sessio... more — In this paper, we analyze a real-life application of virtualization: the Italtel Virtual Session Border Controller (VSBC). The measurements obtained in ad hoc loading experiments show that the VSBC performance is not linear with respect to variations in the call rate. Such a behavior is not in accordance with the theoretical results predicted by standard statistical tools based on queuing theory. As a consequence, particular attention must be paid to accurately assess the VSBC performance, because inaccurate estimates could lead to undue costs, or under-performing solutions. To overcome this problem, a novel approach to accurately predict the VSBC performance is proposed, which allows optimizing the system behavior and minimizing its costs.
—Network Function Virtualization (NFV) has become a widely acclaimed approach to facilitate the m... more —Network Function Virtualization (NFV) has become a widely acclaimed approach to facilitate the management and orchestration of network services. However, after rapidly achieving a widespread success, NFV is now challenged by the overwhelming demand of computing power originated by the never-ending growth of innovative applications coming from the Internet world. To overcome this problem, the use of h/w acceleration combined with NFV has been proposed. This way, the computing performance of commodity servers can be greatly enhanced, without losing the advantages offered by NFV in service management. In this paper, to demonstrate the potentialities of NFV and h/w acceleration, a Virtual Network Function for video coding (video Transcoding Unit – vTU) is presented. The vTU is accelerated by a General Purpose GPU, and is based on Open Source software packages for media processing. The vTU architecture is firstly described in details. A thorough characterization of its computing performance is then reported, and the obtained results are compared to those achieved with non-accelerated and/or non-virtualized versions of the vTU itself. Also, the performance provided by an original, GPU accelerated version of the VP8 encoder is presented. The activities described in this paper have been carried out within the EU FP7 T-NOVA project.
—A key motivation behind the success of Cloud Computing is that virtualization allows significant... more —A key motivation behind the success of Cloud Computing is that virtualization allows significant energy and cost savings by sharing physical resources. Another source of savings in virtualized architectures is the use of h/w accelerators (e.g. GPUs, FPGAs). This paper analyzes the performance achieved by a computationally demanding task running on a commodity server when a GPU-based accelerator is adopted. In the analysis, the VP8 video encoder has been used, with its most intensive functional block (motion estimation) implemented in the GPU. A simple but effective model to predict the achieved CPU usage savings is provided, and experimentally validated. The performance achieved with different numbers of simultaneous encoding sessions and used CPU cores is presented and discussed. The results show that the hybrid CPU-GPU implementation can provide computational time savings from 20% to 300%, without any quality degradation. The presented results have been obtained within the FP7 T-NOVA Project.
In the paper, the problem of assessing the speech quality provided by a real-life telephone-type ... more In the paper, the problem of assessing the speech quality provided by a real-life telephone-type network is considered. Two different approaches to the quoted problem are presented: subjective approach, based on customer surveys or trained operators, and objective approach, based on instrumental measurements of key transmission parameters. Advantages and drawbacks associated with the quoted approaches are summarised and briefly discussed. An objective approach based on an In-service Nonintrusive Measurement Device (INMD) is also presented. Finally, real life experiments, which show the effectiveness of the INMD approach are reported and discussed.
—A noise-insensitive technique for the discrimination between speech and voice-band data transmis... more —A noise-insensitive technique for the discrimination between speech and voice-band data transmissions over a telephone-type system is presented. The proposed procedure combines together the evaluation of some meaningful parameters extracted from the observed speech or data communication signal, with an analysis of the statistical moments associated to these parameters. In this way, the discrimination capability associated to the extracted parameters is enforced by the moment analysis that better exploits the time-varying properties of speech signals. Experimental results, that show the good behavior of the classifier in terms of probability of error with respect to signal-to-noise ratio (SNR) are reported and discussed.
—The paper analyzes the overall conversion error of a noisy digitizer affected by Gaussian noise ... more —The paper analyzes the overall conversion error of a noisy digitizer affected by Gaussian noise at its input or generated within the digitizer itself. It is shown that, under mild conditions concerning the ratio between the input noise standard deviation and the quantization step, the overall conversion error can be mod-eled by a Gaussian random variable uncorrelated with the input sequence. The power of the global conversion error is evaluated in closed formulae together with its degree of variability. Numerical simulations support the proposed analysis.
—The paper presents an in-service nonintrusive technique for the measurement of the echo path del... more —The paper presents an in-service nonintrusive technique for the measurement of the echo path delay and echo attenuation in telephone-type networks. The proposed method is based on a cross-correlation technique in conjunction with adap-tive filtering of the observed transmitted signal. Experimental results show the high accuracy and robustness of the proposed measurement procedure.
—The paper presents an in-service, nonintrusive technique for the measurement of noise level and ... more —The paper presents an in-service, nonintrusive technique for the measurement of noise level and active speech level in telecommunication systems. It is based on the segmentation of the signal observed during a telephone call into active speech and noise intervals and on an improved method for level estimation via the determination of the noise-level probability density function. Experimental results show the high accuracy of the method also under poor signal-to-noise ratio conditions and its robustness with respect to other real-life impairments found in telecommunication lines.
—The basic assumptions of analog-to-digital converter (ADC) effective bit estimation procedures a... more —The basic assumptions of analog-to-digital converter (ADC) effective bit estimation procedures are analyzed and closed-form expressions that link accuracy to the parameters that describe the measurement conditions are derived. It is shown that the achievable accuracy mainly depends on the ratio between the number of acquired samples and the number of ADC quantization levels. Furthermore, the effect of broad-band noise superimposed to the sinewave employed as test input is analyzed. Results useful for the design of the estimation procedure itself are also provided.
—An in-service, nonintrusive technique for the characterization of impulsive noise in telecommuni... more —An in-service, nonintrusive technique for the characterization of impulsive noise in telecommunication systems is presented. It is based on the segmentation of the signal observed during a telephone call in speech and noise frames. The signal observed during noise frames is further processed by means of a hypothesis testing procedure in order to detect the presence of impulses. Experimental results that show the effectiveness of the proposed technique are presented and discussed.
A modified cepstral analysis for accurate estimation of the echo delay and the echo loss in a tel... more A modified cepstral analysis for accurate estimation of the echo delay and the echo loss in a telecommunication system is presented. It is based on the optimization of a parametric transformation of the observed signal energy spectrum. Simulation results that show the effectiveness and the accuracy of the proposed method are reported and discussed.
In the paper, the problem of assessing the speech quality provided by a real-life telephone-type ... more In the paper, the problem of assessing the speech quality provided by a real-life telephone-type network is considered. Two different approaches to the quoted problem are presented: subjective approach, based on customer surveys or trained operators, and objective approach, based on instrumental measurements of key transmission parameters. Advantages and drawbacks associated with the quoted approaches are summarised and briefly discussed. An objective approach based on an In-service Nonintrusive Measurement Device (INMD) is also presented. Finally, real life experiments, which show the effectiveness of the INMD approach are reported and discussed.
A lower bound to the accuracy of commonly adopted estimation methods for the overall conversion e... more A lower bound to the accuracy of commonly adopted estimation methods for the overall conversion error power of a sinusoidal input signal is provided in the paper. It is shown that such bound depends only on the conversion error power and is inversely proportional to the number of samples of the quantized sequence. Simulation results are reported that validate the obtained theoretical results. The provided analysis is useful for the design of estimation procedures that satisfy the accuracy requirements of the test.
Abstract—The promises of Network Functions Virtualization
(NFV) complemented with Software Define... more Abstract—The promises of Network Functions Virtualization (NFV) complemented with Software Defined Networking (SDN) can be simply stated as: get much more, pay much less. Adopting such paradigms, Service Operators expect to achieve high reductions in capital investments and greater operational agility. However, applying these concepts to existing networks will require challenging architectural updates, as well as deep changes in service models and operating procedures. To analyze such aspects, in this paper we provide an overview of the experience gathered at Italtel R&D labs in this field, and discuss state-of-the-art and future perspectives of these technologies. In particular, we describe how NFV was applied to a specific network function, the Session Border Controller, solving some related technical issues of general interest, and providing scalability and flexibility. Finally, we discuss the evolution of this virtualized network function, and its integration into an SDN-based network.
A frequency-domain approach for the estimation of ADC performance parameters is considered in the... more A frequency-domain approach for the estimation of ADC performance parameters is considered in the paper. Closed-form formulae that describe the behaviour of the proposed estimator are reported and discussed, together with simulation results that validite the theoretical analysis.
A measurement system for in-service characterization of telephone-type networks is described. It ... more A measurement system for in-service characterization of telephone-type networks is described. It is based on in-line Digital Signal Processing of the transmitted signal observed at an easily accessible test-point. The adopted techniques for the estimation of the considered parameters are summarized and discussed, together with an example of a measurement session performed on a real-life telephone-type network.
— In this paper, we analyze a real-life application of virtualization: the Italtel Virtual Sessio... more — In this paper, we analyze a real-life application of virtualization: the Italtel Virtual Session Border Controller (VSBC). The measurements obtained in ad hoc loading experiments show that the VSBC performance is not linear with respect to variations in the call rate. Such a behavior is not in accordance with the theoretical results predicted by standard statistical tools based on queuing theory. As a consequence, particular attention must be paid to accurately assess the VSBC performance, because inaccurate estimates could lead to undue costs, or under-performing solutions. To overcome this problem, a novel approach to accurately predict the VSBC performance is proposed, which allows optimizing the system behavior and minimizing its costs.
—Network Function Virtualization (NFV) has become a widely acclaimed approach to facilitate the m... more —Network Function Virtualization (NFV) has become a widely acclaimed approach to facilitate the management and orchestration of network services. However, after rapidly achieving a widespread success, NFV is now challenged by the overwhelming demand of computing power originated by the never-ending growth of innovative applications coming from the Internet world. To overcome this problem, the use of h/w acceleration combined with NFV has been proposed. This way, the computing performance of commodity servers can be greatly enhanced, without losing the advantages offered by NFV in service management. In this paper, to demonstrate the potentialities of NFV and h/w acceleration, a Virtual Network Function for video coding (video Transcoding Unit – vTU) is presented. The vTU is accelerated by a General Purpose GPU, and is based on Open Source software packages for media processing. The vTU architecture is firstly described in details. A thorough characterization of its computing performance is then reported, and the obtained results are compared to those achieved with non-accelerated and/or non-virtualized versions of the vTU itself. Also, the performance provided by an original, GPU accelerated version of the VP8 encoder is presented. The activities described in this paper have been carried out within the EU FP7 T-NOVA project.
—A key motivation behind the success of Cloud Computing is that virtualization allows significant... more —A key motivation behind the success of Cloud Computing is that virtualization allows significant energy and cost savings by sharing physical resources. Another source of savings in virtualized architectures is the use of h/w accelerators (e.g. GPUs, FPGAs). This paper analyzes the performance achieved by a computationally demanding task running on a commodity server when a GPU-based accelerator is adopted. In the analysis, the VP8 video encoder has been used, with its most intensive functional block (motion estimation) implemented in the GPU. A simple but effective model to predict the achieved CPU usage savings is provided, and experimentally validated. The performance achieved with different numbers of simultaneous encoding sessions and used CPU cores is presented and discussed. The results show that the hybrid CPU-GPU implementation can provide computational time savings from 20% to 300%, without any quality degradation. The presented results have been obtained within the FP7 T-NOVA Project.
In the paper, the problem of assessing the speech quality provided by a real-life telephone-type ... more In the paper, the problem of assessing the speech quality provided by a real-life telephone-type network is considered. Two different approaches to the quoted problem are presented: subjective approach, based on customer surveys or trained operators, and objective approach, based on instrumental measurements of key transmission parameters. Advantages and drawbacks associated with the quoted approaches are summarised and briefly discussed. An objective approach based on an In-service Nonintrusive Measurement Device (INMD) is also presented. Finally, real life experiments, which show the effectiveness of the INMD approach are reported and discussed.
—A noise-insensitive technique for the discrimination between speech and voice-band data transmis... more —A noise-insensitive technique for the discrimination between speech and voice-band data transmissions over a telephone-type system is presented. The proposed procedure combines together the evaluation of some meaningful parameters extracted from the observed speech or data communication signal, with an analysis of the statistical moments associated to these parameters. In this way, the discrimination capability associated to the extracted parameters is enforced by the moment analysis that better exploits the time-varying properties of speech signals. Experimental results, that show the good behavior of the classifier in terms of probability of error with respect to signal-to-noise ratio (SNR) are reported and discussed.
—The paper analyzes the overall conversion error of a noisy digitizer affected by Gaussian noise ... more —The paper analyzes the overall conversion error of a noisy digitizer affected by Gaussian noise at its input or generated within the digitizer itself. It is shown that, under mild conditions concerning the ratio between the input noise standard deviation and the quantization step, the overall conversion error can be mod-eled by a Gaussian random variable uncorrelated with the input sequence. The power of the global conversion error is evaluated in closed formulae together with its degree of variability. Numerical simulations support the proposed analysis.
—The paper presents an in-service nonintrusive technique for the measurement of the echo path del... more —The paper presents an in-service nonintrusive technique for the measurement of the echo path delay and echo attenuation in telephone-type networks. The proposed method is based on a cross-correlation technique in conjunction with adap-tive filtering of the observed transmitted signal. Experimental results show the high accuracy and robustness of the proposed measurement procedure.
—The paper presents an in-service, nonintrusive technique for the measurement of noise level and ... more —The paper presents an in-service, nonintrusive technique for the measurement of noise level and active speech level in telecommunication systems. It is based on the segmentation of the signal observed during a telephone call into active speech and noise intervals and on an improved method for level estimation via the determination of the noise-level probability density function. Experimental results show the high accuracy of the method also under poor signal-to-noise ratio conditions and its robustness with respect to other real-life impairments found in telecommunication lines.
—The basic assumptions of analog-to-digital converter (ADC) effective bit estimation procedures a... more —The basic assumptions of analog-to-digital converter (ADC) effective bit estimation procedures are analyzed and closed-form expressions that link accuracy to the parameters that describe the measurement conditions are derived. It is shown that the achievable accuracy mainly depends on the ratio between the number of acquired samples and the number of ADC quantization levels. Furthermore, the effect of broad-band noise superimposed to the sinewave employed as test input is analyzed. Results useful for the design of the estimation procedure itself are also provided.
—An in-service, nonintrusive technique for the characterization of impulsive noise in telecommuni... more —An in-service, nonintrusive technique for the characterization of impulsive noise in telecommunication systems is presented. It is based on the segmentation of the signal observed during a telephone call in speech and noise frames. The signal observed during noise frames is further processed by means of a hypothesis testing procedure in order to detect the presence of impulses. Experimental results that show the effectiveness of the proposed technique are presented and discussed.
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Papers by Paglierani Pietro
(NFV) complemented with Software Defined Networking (SDN)
can be simply stated as: get much more, pay much less.
Adopting such paradigms, Service Operators expect to achieve
high reductions in capital investments and greater operational
agility. However, applying these concepts to existing networks
will require challenging architectural updates, as well as deep
changes in service models and operating procedures. To
analyze such aspects, in this paper we provide an overview of
the experience gathered at Italtel R&D labs in this field, and
discuss state-of-the-art and future perspectives of these
technologies. In particular, we describe how NFV was applied
to a specific network function, the Session Border Controller,
solving some related technical issues of general interest, and
providing scalability and flexibility. Finally, we discuss the
evolution of this virtualized network function, and its
integration into an SDN-based network.
(NFV) complemented with Software Defined Networking (SDN)
can be simply stated as: get much more, pay much less.
Adopting such paradigms, Service Operators expect to achieve
high reductions in capital investments and greater operational
agility. However, applying these concepts to existing networks
will require challenging architectural updates, as well as deep
changes in service models and operating procedures. To
analyze such aspects, in this paper we provide an overview of
the experience gathered at Italtel R&D labs in this field, and
discuss state-of-the-art and future perspectives of these
technologies. In particular, we describe how NFV was applied
to a specific network function, the Session Border Controller,
solving some related technical issues of general interest, and
providing scalability and flexibility. Finally, we discuss the
evolution of this virtualized network function, and its
integration into an SDN-based network.