Maria Luisa MERANI - Profile on Academia.edu (original) (raw)
Papers by Maria Luisa MERANI
arXiv (Cornell University), May 22, 2019
This work performs a preliminary, comparative analysis of the endto-end quality guaranteed by Voi... more This work performs a preliminary, comparative analysis of the endto-end quality guaranteed by Voice over LTE (VoLTE), examining several millions of VoLTE calls that employ two popular speech audio codecs, namely, Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate WideBand (AMR-WB). To assess call quality, VQmon®, an enhanced version of the standardized E-Model, is utilized. The study reveals to what extent AMR-WB based calls are more robust against network impairments than their narrowband counterparts; it further shows that the dependence of call quality on the packet loss rate is approximately exponential when the AMR codec is used, whereas it is nearly linear for the AMR-WB codec.
MPλS vs LOBS in an Optical Burst Switching Node: Impact of Long-Range Dependent Traffic on Multiclass Services
Optical Communications and Networks - Proceedings of the First International Conference on ICOCN 2002, 2002
IEEE Communications Letters, 2001
This letter determines the capacity of a TDD-TD/CDMA architecture which supports different classe... more This letter determines the capacity of a TDD-TD/CDMA architecture which supports different classes of subscribers and adopts an interference-driven admission control policy. The blocking probability of the system users are evaluated under various traffic conditions for several uplink/downlink configurations of the time slots, demonstrating that the time division full duplex approach needs a careful tuning in order to maximize system capacity.
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications
Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employ... more Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employing the recently proposed quasi-orthogonal sequences are put forth in this paper. It is demonstrated how different allocation strategies of quasi-orthogonal codes alter the interference level suffered by active units; it is also shown how to shape the rate of interference growth as a function of the number of active users within the reference cell, by implementing some specific code allocation patterns. The performance, in terms of average bit error probability, achieved by various schemes is assessed in a frequency selective fading environment, and the advantages of different solutions highlighted.
Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different... more Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different versions of the same media content to adapt the delivery process over the Internet to dynamic bandwidth fluctuations and different user device capabilities. The peer-to-peer (P2P) paradigm for video streaming allows to leverage the cooperation among peers, guaranteeing to serve every video request with increased scalability and reduced cost. We propose to combine these two approaches in a P2P-DASH architecture, exploiting the potentiality of both. The new platform is made of several swarms, and a different DASH representation is streamed within each of them; unlike client-server DASH architectures, where each client autonomously selects which version to download according to current network conditions and to its device resources, we put forth a new rate control strategy implemented at peer site to maintain a good viewing quality to the local user and to simultaneously guarantee the succ...
Abstract-In recent years, classical Internet applications have been accompanied by the surging of... more Abstract-In recent years, classical Internet applications have been accompanied by the surging of a great variety of new services and exciting possibilities. Among such broad range, two particular phenomena are highly successful: Online Social Networks (OSNs) and Peer-to-Peer (P2P) services. This paper merges these distinct worlds, via the proposal of a P2P streaming system that takes advantage of the friendship relationships of an underlying OSN, to better distribute videos among the overlay peers that are also friends within the OSN. A category of privileged users is therefore created, that is guaranteed a satisfying viewing experience when the P2P overlay operates in critical conditions, i.e, when bandwidth availability is scarce. We show that the help of direct friends, two-hops away friends and, in the limit, of the entire OSN community brings in considerable advantages to the peers that are OSN members. In particular: the number of those among them that are able to download th...
Service Differentiation in Optical Burst Switching: Performance Evaluation under LRD Traffic
This letter puts forth an analytical approach to evaluate the outage probability of power-based N... more This letter puts forth an analytical approach to evaluate the outage probability of power-based NOMA on the uplink of a 5G cell, the outage being defined as the event where the receiver fails to successfully decode all the simultaneously received signals. In the examined scenario, Successive Interference Cancellation (SIC) is considered and an arbitrary number of superimposed signals is present. For the Rayleigh fading case, the outage probability is provided in closed-form, clearly outlining its dependency on the signal-to-noise ratio of the users that are simultaneously transmitting, as well as on their distance from the receiver.
Network measurement and telemetry techniques are central to the management of today's compute... more Network measurement and telemetry techniques are central to the management of today's computer networks. One popular technique with several applications is the estimation of traffic matrices. Existing traffic matrix inference approaches that use statistical methods, often make assumptions on the structure of the matrix that may be invalid. Data-driven methods, instead, often use detailed information about the network topology that may be unavailable or impractical to collect. Inspired by the field of image processing, we propose a superresolution technique for traffic matrix inference that does not require any knowledge on the structural properties of the matrix elements to infer, nor a large data collection. Our experiments with anonymized Internet traces demonstrate that the proposed approach can infer fine-grained network traffic with high precision outperforming existing data interpolation techniques, such as bicubic interpolation.
IEEE Access
Cellular Vehicle-to-Everything (C-V2X) communications are the key to connected and autonomous dri... more Cellular Vehicle-to-Everything (C-V2X) communications are the key to connected and autonomous driving, and pave the way for future Intelligent Transport Systems (ITS). To support non-safety and safety critical applications in the demanding out-of-coverage scenario, the 3rd Generation Partnership Project (3GPP) has standardized the distributed C-V2X Mode 4 solution, whose behavior has been thoroughly analyzed for periodic traffic. In the current work, the problem of allocating aperiodic traffic in Mode 4 is tackled, a matter that has not been addressed before and that raises several challenging questions. A solution for serving such traffic type is put forth, and an analytical insight on the attainable performance is offered. Further, it is numerically proved that guaranteeing aperiodic flows good service levels is hard when their packets are not small sized. This holds true even for sophisticated physical layer choices and at relatively modest traffic densities, revealing that novel approaches to radio resource assignment are a necessity in Fifth Generation (5G) vehicular communications. INDEX TERMS C-V2X, aperiodic vehicular traffic, vehicular communications, 5G.
This work puts forth a novel analytical approach to evaluate the performance that power-domain No... more This work puts forth a novel analytical approach to evaluate the performance that power-domain Non-Orthogonal Multiple Access (NOMA) achieves on the uplink of a single cell. A dynamic-ordered Successive Interference Cancellation (SIC) receiver is considered, and both the case of Rayleigh and lognormal-shadowed Rayleigh fading are examined. System performance is assessed analytically, deriving either exact or approximated closed-form expressions, whose correctness and excellent accuracy are validated through Monte Carlo simulations. The analysis discloses the effects on performance of an arbitrary number n of simultaneously transmitting users, therefore unveiling where the insourmountable limits of the dynamic-ordered SIC receiver lie. Moreover, the proposed methodology allows to quantifythe impact of lognormal shadowing on NOMA efficacy.
This paper develops a novel Machine Learning (ML)-based strategy to distribute aperiodic Cooperat... more This paper develops a novel Machine Learning (ML)-based strategy to distribute aperiodic Cooperative Awareness Messages (CAMs) through cellular Vehicle-to-Vehicle (V2V) communications. According to it, an ML algorithm is employed by each vehicle to forecast its future CAM generation times; then, the vehicle autonomously selects the radio resources for message broadcasting on the basis of the forecast provided by the algorithm. This action is combined with a wise analysis of the radio resources available for transmission, that identifies subchannels where collisions might occur, to avoid selecting them.Extensive simulations show that the accuracy in the prediction of the CAMs’ temporal pattern is excellent. Exploiting this knowledge in the strategy for radio resource assignment, and carefully identifying idle resources, allows to outperform the legacy LTE-V2X Mode 4 in all respects.
IEEE Networking Letters
This work puts forward a supervised ML technique to determine the Quality of Experience (QoE) of ... more This work puts forward a supervised ML technique to determine the Quality of Experience (QoE) of VoIP calls. It takes its beginning from an investigation on VQmon ® , an enhanced E-model version that estimates the quality of IPbased voice calls adopting an objective approach. The current study demonstrates VQmon ® shortcomings via a comparison between the Mean Opinion Score (MOS) values this technique predicts and the actual average ratings collected from a subjective listening quality campaign. It proposes to deploy Ordinal Logistic Regression (OLR) for speech quality assessment, and results disclose that OLR outperforms popular ML algorithms, in accuracy and confusion matrices. Index Terms-Machine Learning (ML); Mean Opinion Score (MOS); Quality of Experience (QoE); Voice over IP (VoIP); Speech Quality Assessment.
2019 15th International Wireless Communications & Mobile Computing Conference (IWCMC), Jun 1, 2019
This work performs a comparative analysis of the end-to-end quality guaranteed by Voice over LTE ... more This work performs a comparative analysis of the end-to-end quality guaranteed by Voice over LTE (VoLTE), examining several millions of VoLTE calls that employ two popular speech audio codecs, namely, Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wide Band (AMR-WB). To assess call quality, VQmon R , an enhanced version of the standardized E-Model, is utilized. The study reveals to what extent AMR-WB based calls are more robust against network impairments than their narrowband counterparts; it further shows that the dependence of call quality on the packet loss rate is approximately exponential for both types of codec.
2018 IEEE International Conference on Communications (ICC), May 1, 2018
This work puts forth an analytical approach to evaluate the recovery failure probability of power... more This work puts forth an analytical approach to evaluate the recovery failure probability of powerbased Non-Orthogonal Multiple Access (NOMA) on the uplink of a 5G cell, the recovery failure being defined as the unfortunate event where the receiver is unable to decode even one out of the n simultaneously received signals. In the examined scenario, Successive Interference Cancellation (SIC) is considered and an arbitrary number of superimposed signals is present. For the Rayleigh fading case, the recovery failure probability is provided in closed-form, clearly outlining its dependency on the signal-to-noise ratio of the users that are simultaneously transmitting, as well as on their distance from the receiver.
2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), Aug 1, 2018
This work investigates the performance of a multihop scheme for the dissemination of road safety ... more This work investigates the performance of a multihop scheme for the dissemination of road safety messages on highway segments, employing the recently standardized LTE-A Cellular Vehicle-to-Everything (C-V2X) technology. In order to guarantee a seamless service in areas where cellular coverage is unavailable, vehicles directly communicate over the unlicensed ITS 5.9 GHz frequency band, operating in accordance to Mode 4 of the C-V2X standard. The behavior of the proposed scheme reveals that the delivery of safety messages can successfully take place on a dedicated radio channel, as well as on a shared channel where periodic messages are broadcast at the maximum frequency foreseen by ETSI.
IEEE Wireless Communications Letters
New channel simulation models are needed for the study of future wireless networks, 5G and beyond... more New channel simulation models are needed for the study of future wireless networks, 5G and beyond. A novel simulation technique dubbed weighted-counting is proposed. It is used to generate random variates having the two-wave with diffuse power (TWDP) fading amplitude distribution. The TWDP channel model describes high-speed train, femtocell, sea surface, heterogeneous and other channels having two different dominant line-of-sight waves as well as scatter power components. Index Terms-Fading channels, line of sight, random variate generation, simulation, two-wave with diffuse power (TWDP), weighted-counter. I. INTRODUCTION T HE two-wave with diffuse power (TWDP) fading model is an important model for present and future wireless communication systems [1]-[7]. In this model, the received signal has two dominant specular components of comparable powers, plus numerous lower power scatter components of comparable powers. This model can represent high-speed train, femtocell, sea surface, heterogeneous and other channels, so statistically accurate TWDP fading simulation is needed. Yet, to the best of the authors' knowledge, no efficient method for generating TWDP amplitude random variates has been reported in the literature. The contributions of this letter are first, to propose a novel simulation method dubbed, "weighted counting", and second to study how the weighted counting method can be used to simulate the amplitude of two-wave with diffuse power (TWDP) fading channels. In theory, the direct method [8] can be used to generate random variates having any probability distribution. However, in practice the direct method sometimes can not be used in cases where the inverse function of the cumulative probability distribution (CDF) is not known, or is not known in a simple form. While numerical inversion of the CDF can be efficiently employed in some cases, it may be complicated, or it may require extensive tables of coefficients for different parameter values that define the CDF [9]. The direct method sometimes cannot be used in cases where the inverse TWDP CDF function is not known. Numerical inversion of the CDF is not viable because the TWDP distribution has three degrees of freedom. In the alternative, the rejection method of generating random variates is simple and effective in some cases where the direct
ACM Transactions on Multimedia Computing, Communications, and Applications, 2016
Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different... more Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different versions of the same media content to adapt the delivery process over the Internet to dynamic bandwidth fluctuations and different user device capabilities. The peer-to-peer (P2P) paradigm for video streaming allows us to leverage the cooperation among peers, guaranteeing the service of video requests with increased scalability and reduced cost. We propose to combine these two approaches in a P2P-DASH architecture, exploiting the potentiality of both. The new platform is made of several swarms and a different DASH representation is streamed within each of them; unlike client-server DASH architectures, where each client autonomously selects which version to download according to current network conditions and to its device resources, we put forth a new rate control strategy implemented at peer site to maintain a good viewing quality to the local user and to simultaneously guarantee the s...
A Novel Rate Control Strategy for Adaptive Video Streaming in P2P Overlays
2015 IEEE Global Communications Conference (GLOBECOM), 2014
This work proposes a novel P2P-DASH architecture that jointly leverages the intrinsic cooperation... more This work proposes a novel P2P-DASH architecture that jointly leverages the intrinsic cooperation property of P2P and the adaptivity of Dynamic Adaptive Streaming over HTTP (DASH) to deliver videos to a large population of users with heterogeneous streaming requests. The system is made of several overlays, each distributing a different DASH representation; every peer within the system autonomously enforces a newly devised rate control strategy that steers its movements from one overlay to another, in order to maintain a good viewing experience and to simultaneously guarantee the successful operation of the P2P overlays. The effectiveness of the solution is demonstrated through simulation and it indicates that the P2P-DASH platform is able to guarantee its users a very good performance, much more satisfying than in a conventional P2P environment where DASH is not employed. Moreover, through the comparison with a reference system modeled via the Integer Linear Programming (ILP) approach,it is shown that our system outperforms such reference architecture in terms of viewing quality; at the same time, the number of users streaming the video at the desired bit rate is extremely close to the optimum of the ILP setting in the most favorable scenarios, and only moderately suboptimal in the worst.
This paper investigates the performance of a complete OBS (Optical Burst Switched) network that i... more This paper investigates the performance of a complete OBS (Optical Burst Switched) network that implements the JET (Just Enough Time) reservation mechanism. The network under examination adopts a core node architecture with no fiber delay lines and a limited set of wavelength converters, while featuring an edge node architecture with a mix of input, output and shared buffers. We investigate the overall network performance and design, specifically focusing on burst delay and end-to-end TCP throughput. In order to study the OBS network behavior, we develop a modular and flexible simulation tool, that we call MOBSSIM (Modular OBS Simulator). MOBSSIM is the means to accurately build an arbitrary topology OBS network via its main functional blocks, edge and core routers: its sound degree of development enables us to accurately evaluate several figures of merit, e.g., burst blocking probability and delay, and also allows for a critical comparison of alternative design solutions in terms of assembly algorithms, reservation strategies and QoS oriented routing.
arXiv (Cornell University), May 22, 2019
This work performs a preliminary, comparative analysis of the endto-end quality guaranteed by Voi... more This work performs a preliminary, comparative analysis of the endto-end quality guaranteed by Voice over LTE (VoLTE), examining several millions of VoLTE calls that employ two popular speech audio codecs, namely, Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate WideBand (AMR-WB). To assess call quality, VQmon®, an enhanced version of the standardized E-Model, is utilized. The study reveals to what extent AMR-WB based calls are more robust against network impairments than their narrowband counterparts; it further shows that the dependence of call quality on the packet loss rate is approximately exponential when the AMR codec is used, whereas it is nearly linear for the AMR-WB codec.
MPλS vs LOBS in an Optical Burst Switching Node: Impact of Long-Range Dependent Traffic on Multiclass Services
Optical Communications and Networks - Proceedings of the First International Conference on ICOCN 2002, 2002
IEEE Communications Letters, 2001
This letter determines the capacity of a TDD-TD/CDMA architecture which supports different classe... more This letter determines the capacity of a TDD-TD/CDMA architecture which supports different classes of subscribers and adopts an interference-driven admission control policy. The blocking probability of the system users are evaluated under various traffic conditions for several uplink/downlink configurations of the time slots, demonstrating that the time division full duplex approach needs a careful tuning in order to maximize system capacity.
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications
Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employ... more Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employing the recently proposed quasi-orthogonal sequences are put forth in this paper. It is demonstrated how different allocation strategies of quasi-orthogonal codes alter the interference level suffered by active units; it is also shown how to shape the rate of interference growth as a function of the number of active users within the reference cell, by implementing some specific code allocation patterns. The performance, in terms of average bit error probability, achieved by various schemes is assessed in a frequency selective fading environment, and the advantages of different solutions highlighted.
Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different... more Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different versions of the same media content to adapt the delivery process over the Internet to dynamic bandwidth fluctuations and different user device capabilities. The peer-to-peer (P2P) paradigm for video streaming allows to leverage the cooperation among peers, guaranteeing to serve every video request with increased scalability and reduced cost. We propose to combine these two approaches in a P2P-DASH architecture, exploiting the potentiality of both. The new platform is made of several swarms, and a different DASH representation is streamed within each of them; unlike client-server DASH architectures, where each client autonomously selects which version to download according to current network conditions and to its device resources, we put forth a new rate control strategy implemented at peer site to maintain a good viewing quality to the local user and to simultaneously guarantee the succ...
Abstract-In recent years, classical Internet applications have been accompanied by the surging of... more Abstract-In recent years, classical Internet applications have been accompanied by the surging of a great variety of new services and exciting possibilities. Among such broad range, two particular phenomena are highly successful: Online Social Networks (OSNs) and Peer-to-Peer (P2P) services. This paper merges these distinct worlds, via the proposal of a P2P streaming system that takes advantage of the friendship relationships of an underlying OSN, to better distribute videos among the overlay peers that are also friends within the OSN. A category of privileged users is therefore created, that is guaranteed a satisfying viewing experience when the P2P overlay operates in critical conditions, i.e, when bandwidth availability is scarce. We show that the help of direct friends, two-hops away friends and, in the limit, of the entire OSN community brings in considerable advantages to the peers that are OSN members. In particular: the number of those among them that are able to download th...
Service Differentiation in Optical Burst Switching: Performance Evaluation under LRD Traffic
This letter puts forth an analytical approach to evaluate the outage probability of power-based N... more This letter puts forth an analytical approach to evaluate the outage probability of power-based NOMA on the uplink of a 5G cell, the outage being defined as the event where the receiver fails to successfully decode all the simultaneously received signals. In the examined scenario, Successive Interference Cancellation (SIC) is considered and an arbitrary number of superimposed signals is present. For the Rayleigh fading case, the outage probability is provided in closed-form, clearly outlining its dependency on the signal-to-noise ratio of the users that are simultaneously transmitting, as well as on their distance from the receiver.
Network measurement and telemetry techniques are central to the management of today's compute... more Network measurement and telemetry techniques are central to the management of today's computer networks. One popular technique with several applications is the estimation of traffic matrices. Existing traffic matrix inference approaches that use statistical methods, often make assumptions on the structure of the matrix that may be invalid. Data-driven methods, instead, often use detailed information about the network topology that may be unavailable or impractical to collect. Inspired by the field of image processing, we propose a superresolution technique for traffic matrix inference that does not require any knowledge on the structural properties of the matrix elements to infer, nor a large data collection. Our experiments with anonymized Internet traces demonstrate that the proposed approach can infer fine-grained network traffic with high precision outperforming existing data interpolation techniques, such as bicubic interpolation.
IEEE Access
Cellular Vehicle-to-Everything (C-V2X) communications are the key to connected and autonomous dri... more Cellular Vehicle-to-Everything (C-V2X) communications are the key to connected and autonomous driving, and pave the way for future Intelligent Transport Systems (ITS). To support non-safety and safety critical applications in the demanding out-of-coverage scenario, the 3rd Generation Partnership Project (3GPP) has standardized the distributed C-V2X Mode 4 solution, whose behavior has been thoroughly analyzed for periodic traffic. In the current work, the problem of allocating aperiodic traffic in Mode 4 is tackled, a matter that has not been addressed before and that raises several challenging questions. A solution for serving such traffic type is put forth, and an analytical insight on the attainable performance is offered. Further, it is numerically proved that guaranteeing aperiodic flows good service levels is hard when their packets are not small sized. This holds true even for sophisticated physical layer choices and at relatively modest traffic densities, revealing that novel approaches to radio resource assignment are a necessity in Fifth Generation (5G) vehicular communications. INDEX TERMS C-V2X, aperiodic vehicular traffic, vehicular communications, 5G.
This work puts forth a novel analytical approach to evaluate the performance that power-domain No... more This work puts forth a novel analytical approach to evaluate the performance that power-domain Non-Orthogonal Multiple Access (NOMA) achieves on the uplink of a single cell. A dynamic-ordered Successive Interference Cancellation (SIC) receiver is considered, and both the case of Rayleigh and lognormal-shadowed Rayleigh fading are examined. System performance is assessed analytically, deriving either exact or approximated closed-form expressions, whose correctness and excellent accuracy are validated through Monte Carlo simulations. The analysis discloses the effects on performance of an arbitrary number n of simultaneously transmitting users, therefore unveiling where the insourmountable limits of the dynamic-ordered SIC receiver lie. Moreover, the proposed methodology allows to quantifythe impact of lognormal shadowing on NOMA efficacy.
This paper develops a novel Machine Learning (ML)-based strategy to distribute aperiodic Cooperat... more This paper develops a novel Machine Learning (ML)-based strategy to distribute aperiodic Cooperative Awareness Messages (CAMs) through cellular Vehicle-to-Vehicle (V2V) communications. According to it, an ML algorithm is employed by each vehicle to forecast its future CAM generation times; then, the vehicle autonomously selects the radio resources for message broadcasting on the basis of the forecast provided by the algorithm. This action is combined with a wise analysis of the radio resources available for transmission, that identifies subchannels where collisions might occur, to avoid selecting them.Extensive simulations show that the accuracy in the prediction of the CAMs’ temporal pattern is excellent. Exploiting this knowledge in the strategy for radio resource assignment, and carefully identifying idle resources, allows to outperform the legacy LTE-V2X Mode 4 in all respects.
IEEE Networking Letters
This work puts forward a supervised ML technique to determine the Quality of Experience (QoE) of ... more This work puts forward a supervised ML technique to determine the Quality of Experience (QoE) of VoIP calls. It takes its beginning from an investigation on VQmon ® , an enhanced E-model version that estimates the quality of IPbased voice calls adopting an objective approach. The current study demonstrates VQmon ® shortcomings via a comparison between the Mean Opinion Score (MOS) values this technique predicts and the actual average ratings collected from a subjective listening quality campaign. It proposes to deploy Ordinal Logistic Regression (OLR) for speech quality assessment, and results disclose that OLR outperforms popular ML algorithms, in accuracy and confusion matrices. Index Terms-Machine Learning (ML); Mean Opinion Score (MOS); Quality of Experience (QoE); Voice over IP (VoIP); Speech Quality Assessment.
2019 15th International Wireless Communications & Mobile Computing Conference (IWCMC), Jun 1, 2019
This work performs a comparative analysis of the end-to-end quality guaranteed by Voice over LTE ... more This work performs a comparative analysis of the end-to-end quality guaranteed by Voice over LTE (VoLTE), examining several millions of VoLTE calls that employ two popular speech audio codecs, namely, Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wide Band (AMR-WB). To assess call quality, VQmon R , an enhanced version of the standardized E-Model, is utilized. The study reveals to what extent AMR-WB based calls are more robust against network impairments than their narrowband counterparts; it further shows that the dependence of call quality on the packet loss rate is approximately exponential for both types of codec.
2018 IEEE International Conference on Communications (ICC), May 1, 2018
This work puts forth an analytical approach to evaluate the recovery failure probability of power... more This work puts forth an analytical approach to evaluate the recovery failure probability of powerbased Non-Orthogonal Multiple Access (NOMA) on the uplink of a 5G cell, the recovery failure being defined as the unfortunate event where the receiver is unable to decode even one out of the n simultaneously received signals. In the examined scenario, Successive Interference Cancellation (SIC) is considered and an arbitrary number of superimposed signals is present. For the Rayleigh fading case, the recovery failure probability is provided in closed-form, clearly outlining its dependency on the signal-to-noise ratio of the users that are simultaneously transmitting, as well as on their distance from the receiver.
2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), Aug 1, 2018
This work investigates the performance of a multihop scheme for the dissemination of road safety ... more This work investigates the performance of a multihop scheme for the dissemination of road safety messages on highway segments, employing the recently standardized LTE-A Cellular Vehicle-to-Everything (C-V2X) technology. In order to guarantee a seamless service in areas where cellular coverage is unavailable, vehicles directly communicate over the unlicensed ITS 5.9 GHz frequency band, operating in accordance to Mode 4 of the C-V2X standard. The behavior of the proposed scheme reveals that the delivery of safety messages can successfully take place on a dedicated radio channel, as well as on a shared channel where periodic messages are broadcast at the maximum frequency foreseen by ETSI.
IEEE Wireless Communications Letters
New channel simulation models are needed for the study of future wireless networks, 5G and beyond... more New channel simulation models are needed for the study of future wireless networks, 5G and beyond. A novel simulation technique dubbed weighted-counting is proposed. It is used to generate random variates having the two-wave with diffuse power (TWDP) fading amplitude distribution. The TWDP channel model describes high-speed train, femtocell, sea surface, heterogeneous and other channels having two different dominant line-of-sight waves as well as scatter power components. Index Terms-Fading channels, line of sight, random variate generation, simulation, two-wave with diffuse power (TWDP), weighted-counter. I. INTRODUCTION T HE two-wave with diffuse power (TWDP) fading model is an important model for present and future wireless communication systems [1]-[7]. In this model, the received signal has two dominant specular components of comparable powers, plus numerous lower power scatter components of comparable powers. This model can represent high-speed train, femtocell, sea surface, heterogeneous and other channels, so statistically accurate TWDP fading simulation is needed. Yet, to the best of the authors' knowledge, no efficient method for generating TWDP amplitude random variates has been reported in the literature. The contributions of this letter are first, to propose a novel simulation method dubbed, "weighted counting", and second to study how the weighted counting method can be used to simulate the amplitude of two-wave with diffuse power (TWDP) fading channels. In theory, the direct method [8] can be used to generate random variates having any probability distribution. However, in practice the direct method sometimes can not be used in cases where the inverse function of the cumulative probability distribution (CDF) is not known, or is not known in a simple form. While numerical inversion of the CDF can be efficiently employed in some cases, it may be complicated, or it may require extensive tables of coefficients for different parameter values that define the CDF [9]. The direct method sometimes cannot be used in cases where the inverse TWDP CDF function is not known. Numerical inversion of the CDF is not viable because the TWDP distribution has three degrees of freedom. In the alternative, the rejection method of generating random variates is simple and effective in some cases where the direct
ACM Transactions on Multimedia Computing, Communications, and Applications, 2016
Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different... more Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different versions of the same media content to adapt the delivery process over the Internet to dynamic bandwidth fluctuations and different user device capabilities. The peer-to-peer (P2P) paradigm for video streaming allows us to leverage the cooperation among peers, guaranteeing the service of video requests with increased scalability and reduced cost. We propose to combine these two approaches in a P2P-DASH architecture, exploiting the potentiality of both. The new platform is made of several swarms and a different DASH representation is streamed within each of them; unlike client-server DASH architectures, where each client autonomously selects which version to download according to current network conditions and to its device resources, we put forth a new rate control strategy implemented at peer site to maintain a good viewing quality to the local user and to simultaneously guarantee the s...
A Novel Rate Control Strategy for Adaptive Video Streaming in P2P Overlays
2015 IEEE Global Communications Conference (GLOBECOM), 2014
This work proposes a novel P2P-DASH architecture that jointly leverages the intrinsic cooperation... more This work proposes a novel P2P-DASH architecture that jointly leverages the intrinsic cooperation property of P2P and the adaptivity of Dynamic Adaptive Streaming over HTTP (DASH) to deliver videos to a large population of users with heterogeneous streaming requests. The system is made of several overlays, each distributing a different DASH representation; every peer within the system autonomously enforces a newly devised rate control strategy that steers its movements from one overlay to another, in order to maintain a good viewing experience and to simultaneously guarantee the successful operation of the P2P overlays. The effectiveness of the solution is demonstrated through simulation and it indicates that the P2P-DASH platform is able to guarantee its users a very good performance, much more satisfying than in a conventional P2P environment where DASH is not employed. Moreover, through the comparison with a reference system modeled via the Integer Linear Programming (ILP) approach,it is shown that our system outperforms such reference architecture in terms of viewing quality; at the same time, the number of users streaming the video at the desired bit rate is extremely close to the optimum of the ILP setting in the most favorable scenarios, and only moderately suboptimal in the worst.
This paper investigates the performance of a complete OBS (Optical Burst Switched) network that i... more This paper investigates the performance of a complete OBS (Optical Burst Switched) network that implements the JET (Just Enough Time) reservation mechanism. The network under examination adopts a core node architecture with no fiber delay lines and a limited set of wavelength converters, while featuring an edge node architecture with a mix of input, output and shared buffers. We investigate the overall network performance and design, specifically focusing on burst delay and end-to-end TCP throughput. In order to study the OBS network behavior, we develop a modular and flexible simulation tool, that we call MOBSSIM (Modular OBS Simulator). MOBSSIM is the means to accurately build an arbitrary topology OBS network via its main functional blocks, edge and core routers: its sound degree of development enables us to accurately evaluate several figures of merit, e.g., burst blocking probability and delay, and also allows for a critical comparison of alternative design solutions in terms of assembly algorithms, reservation strategies and QoS oriented routing.