ABSTRACT
Taking a look over current mobile implementations, the overhead introduced by the uplink signaling can be prevented reducing the rate of Channel Quality Information reports sent from the mobile users to the channel-aware schedulers located at base stations. In this context, the main goal of the present work is to handle the problem of scheduling traffic flows in modern wireless downlink systems under partially observable channel feedback. With this objective, we focus on the design of an scheduler aimed at minimizing the mean flow delay. In this way, we model the optimization problem as a Partially Observable Markov Decision Process, which depends on the belief state of each users best channel condition. Due to the complexity of the model, we consider the Whittle index-based relaxation, and we derive an index rule which is easily implementable. Whittle indices are obtained offline by means of an algorithm called Adaptive Greedy. The proposed scheduling policy consists in giving priority to the users with the highest Whittle index value. The resulting scheduling solution is then evaluated in both single-class and multi-class scenarios, using real-world channel quality traces in the performed experiments. The obtained results show that the proposed scheduling index rule outperforms the well-known channel-aware disciplines.

ABSTRACT
In the context of cloud-enabled 5G radio access networks with network function virtualization capabilities, we focus on the virtual network function placement problem for a multi-tenant cluster of small cells that provide mobile edge computing services. Under an emerging distributed network architecture and hardware infrastructure, we employ cloud-enabled small cells that integrate micro servers for virtualization execution, equipped with additional hardware appliances. We develop an energy-aware placement solution using a robust optimization approach based on service demand uncertainty in order to minimize the power consumption in the system constrained by network service latency requirements and infrastructure terms. Then, we discuss the results of the proposed placement mechanism in 5G scenarios that combine several service flavours and robust protection values. Once the impact of the service flavour and robust protection on the global power consumption of the system is analyzed, numerical results indicate that our proposal successes to efficiently place the virtual network functions that compose the network services in the available hardware infrastructure while fulfilling service constraints.

ABSTRACT
This paper focuses on multi-tenant 5G networks with virtualization and mobile edge computing capabilities, in the scope of cloud-enabled small cell deployments. In this context, the work here presented deals with the service management and orchestration challenges that arise when handling service mapping on the multi-tenant distributed cloud-enabled radio access network architecture. For that aim, once analysed cloud edge services management and 5G network instantiation in the OpenStack platform, we modify the provided virtual infrastructure manager so as to incorporate virtual network function placement features of the SESAME environment. As main contributions, we adapt the OpenStack application instances to 5G Network Service instantiation, and we include an energy-aware and latency-constrained placement solution.

ABSTRACT
In the context of ultra-dense heterogeneous networks in 5G, we focus on the load balancing problem of elastic traffic in a single macrocell that is supported by a number of small cells. Each small cell is modeled by a single-class processor sharing queue, whereas the macrocell is modelled by a multi-class processor sharing queue. We assume that the macrocell is always consuming energy, while a small cell can be switched off when it is idle with the setup delay penalty. As the main contribution, aimed at minimizing the weighted sum of the mean delay and the mean power consumption in the system, we develop static and dynamic load balancing policies that take into account the setup delay. All the obtained results are analytically founded. The performance of the static policy is evaluated using the achieved analytical expressions which include the static optimal probabilities achieved before, whereas for the dynamic policy we need to carry out simulations using previously obtained numerical results from the first policy iteration procedure. As concluded, numerical results indicate that the dynamic policy outperforms the static policy under realistic settings.

ABSTRACT
Nowadays, citizens are getting used to new ways of agile communications supporting media-enriched and context-aware information. However, the adoption of these evolved technologies in emergency communications between citizens and public authorities face a series of barrier, including the lack of harmonized and interoperable solutions. Different initiatives worldwide are addressing the need for specifying a stable IP-based next generation emergency communications framework. This paper provides a general overview of the different international approaches with especial focus on the European perspective, where the NG112 architecture has been specified and has now entered the testing and evaluation phase.

ABSTRACT
This paper analyzes current standardization situation of 5G and the role network softwarization plays in order to address the challenges the new generation of mobile networks must face. This paper surveys recent documentation from the main stakeholders to pick out the use cases, scenarios and emerging vertical sectors that will be enabled by 5G technologies, and to identify future high-level service requirements. Driven by those service requirements 5G systems will support diverse radio access technology scenarios, meet end-to-end user experienced requirements and provide capability of flexible network deployment and efficient operations. Then, based on the identified requirements, the paper overviews the main 5G technology trends and design principles to address them. In particular, the paper emphasizes the role played by three main technologies, namely SDN, NFV and MEC, and analyzes the main open issues of these technologies in relation to 5G.

ABSTRACT
5G envisages a hyper-connected society where trillions of diverse entities could communicate with each other anywhere and at any time, some of which will demand extremely challenging performance requirements such as sub-millisecond low latency. Mobile Edge Computing (MEC) concept where application computing resources are deployed at the edge of the mobile network in proximity of an end user is a promising solution to improve quality of online experience. To make MEC more flexible and cost-effective Network Functions Virtualisation (NFV) and Software-Defined Networking (SDN) technologies are widely adopted. It leads to significant CAPEX and OPEX reduction with the help of a joint radio-cloud management and orchestration logic. In this paper we discuss and develop a reference architecture for the orchestration and management of the MEC ecosystem. Along with the lifecycle management flows of MEC services, indicating the interactions among the functional modules inside the orchestrator and with external elements, QoS management with a focus on the channel state information technique is presented.

ABSTRACT
Many years of research have been dedicated toward the definition of sophisticated quality of service (QoS) measurement tools and methods. Nonetheless, the results given to end users by most commonly used online speed measurement tools are still far from being accurate. Among other factors, the reliability of the measurement methods is affected by different static and dynamic constraints of involved network nodes and TCP/IP implementations. The clarification of such uncertainties will help establish the baseline for the definition of any comparable and technically feasible measurement methodology, in terms of measurement periods, number of concurrent connections, and convergence time. This article presents a comprehensive description of the research work and proposes mechanisms, aiming to obtain a full understanding of cross-layer effects during a speed test targeting end users.

ABSTRACT
Hurrengo belaunaldiko sareen kudeaketak eskakizun erronkariei aurre egin behar izango die birtualizazio, softwarizazio eta cloud computing bezalako teknologia gaitzaileen aplikazioaren bitartez. Horrelako kudeaketa egoera konplexuan, adimen artifizialaren erabilpena ziklo kognitibo gisa erreminta ezberdintzaile eta ahaltsua bilakatu daiteke sistemaren errendimendu orokorra hobetzeko. Lan honek cloud-ean oinarritutako maila-anitzeko ziklo kognitiboa aurkezten du, aurresandako printzipioak aprobetxatzen dituena, 5G arkitekturaren kontrol eta kudeaketa atazak bermatzeko. Eredu berriztatzaile honek eskema kognitibo zentralizatu eta banatuak konbinatzen ditu modulu erabakitzaileetan sare arkitekturaren maila ezberdinetan, ertza eta cloud ingurunearen arteko elkareragiketa sustatzeko.

ABSTRACT
Adding cognitive capabilities to the wireless networks makes it possible to leverage the control and management information used in the network operation to infer information about the local state and exploit it to improve the overall performance. This paper deals with the combined use of centralized and distributed cognitive cycles integrated at different planes in 5G networks: an integrated data plane, a unified control plane and a cross-layer management plane. This context-aware cognitive schema acts on the decision making modules depending on the monitored environment to prevent failures, balance the virtualized execution and get a global enhancement in the provision of mobile services. The multi-level cognitive cycle supports the interaction between the edge and the cloud blurring the line that separates two paradigms: centralized radio operation and mobile edge services.

ABSTRACT
Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.

ABSTRACT
Modern broadband mobile networks such as 4G LTE are designed to cope with stringent performance levels, i.e. considerable peak data rates and low latencies. With the wide-spreading of LTE networks all over the world, the access to Internet services through mobile connections is increasing considerably, leading to a plethora of mobile services. However, the inherent characteristics of the radio interface results in variable service performance. First, radio resources are shared among the different mobile users and thus the eNB scheduling functions determine the assigned share of resources for each user in a dynamic way. Moreover, the channel quality of each individual user fluctuates over time due to propagation and fading effects. These aspects introduce new issues in the tasks of performance evaluation and adaptive traffic management at different layers of the protocol stack. Currently, there is a gap between advanced research proposals and the actual network and service performance experienced in commercial mobile networks. Although it is generally assumed that the radio channel may introduce considerable quality fluctuations, there is little evidence of the quality dynamics experienced in live LTE networks at different temporal scales. This PhD work aims at providing some insights of these quality variations by analyzing the Channel State Information generated by UEs. Specifically, the document focuses on the downlink direction and on the effects of using spatial multiplexing techniques. From field testing, the main characteristics of the channel quality are studied at the scale of one second. Besides, LTE emulation tests allow evaluating the characteristics of the reported channel quality at the scale of milliseconds. Therefore, valuable information is captured for different layers of the protocol stack. Finally, the impact of the dynamics of these Channel State Information values into different adaptive traffic management schemes is evaluated. For a comprehensive analysis, different mobile network architectures are considered including classical LTE systems and novel proposals such as centralized radio access networks and mobile edge computing.

ABSTRACT
Sare baliabideen esleipenean kalitate subjektiboaren maximizaziorako planifikazioaren garrantziaren eta beharraren aurrean, lan honetan erabiltzaileek hautemandako kalitatearen maximizazioa helburutzat duen sare baliabideen planifikaziorako scheduling algoritmoetan sakondu da. Ikerketa hau matematika arloan ekarpen handia duten Gittins zein Whittle metodoen bidez lortutako kalitate subjektiboaren maximizaziorako scheduling indize erregela motako soluzioen azterketan zentratu da. Modu honetan, lehenik eta behin, bi diziplina horiek aurkeztu dira, Gittins-ena sinpleagoa izanik. Ondoren, bi planifikazio politika horien errendimendua erkatu da, Whittle-en soluzioak emaitza nabarmenki hobeak erakusten dituelarik. Ondorio bezala, indizearen konplexutasunaren eta eskuratu nahi den kalitate subjektiboaren zehaztasunaren arabera, Gittins-en edo Whittle-n oinarritutako proposamena aukeratuko da.

ABSTRACT
One of the most challenging problems in mobile broadband networks is how to assign the available radio resources among the different mobile users. Traditionally, research proposals are either specific to some type of traffic or deal with computationally intensive algorithms aimed at optimizing the delivery of general purpose traffic. Consequently, commercial networks do not incorporate these mechanisms due to the limited hardware resources at the mobile edge. Emerging 5G architectures introduce cloud computing principles to add flexible computational resources to Radio Access Networks. This paper makes use of the Mobile Edge Computing concepts to introduce a new element, denoted as Mobile Edge Scheduler, aimed at minimizing the mean delay of general traffic flows in the LTE downlink. This element runs close to the eNodeB element and implements a novel flow-aware and channel-aware scheduling policy in order to accommodate the transmissions to the available channel quality of end users.

ABSTRACT
This paper presents a novel architecture for optimizing the HTTP-based multimedia delivery in multi-user mobile networks. This proposal combines the usual client-driven dynamic adaptation scheme DASH-3GPP with network-assisted adaptation capabilities, in order to maximize the overall Quality of Experience. The foundation of this combined adaptation scheme is based on two state of the art technologies. On one hand, adaptive HTTP streaming with multi-layer encoding allows efficient media delivery and improves the experienced media quality in highly dynamic channels. Additionally, it enables the possibility to implement network-level adaptations for better coping with multi-user scenarios. On the other hand, mobile edge computing facilitates the deployment of mobile services close to the user. This approach brings new possibilities in modern and future mobile networks, such as close to zero delays and awareness of the radio status. The proposal in this paper introduces a novel element, denoted as Mobile Edge-DASH Adaptation Function, which combines all these advantages to support efficient media delivery in mobile multi-user scenarios. Furthermore, we evaluate the performance enhancements of this content- and user context-aware scheme through simulations of a mobile multimedia scenario.

ABSTRACT
This paper deals with the classical problem of radio resource management in LTE MIMO, with special focus to the specific radio channel characteristics in commercial LTE networks. First, we provide some conclusions about the Channel Quality Information traces obtained through field testing. From this analysis, we perform a series of experiments by means of an LTE emulator in order to evaluate the accuracy of different fading models used in the 3GPP. As a first outcome of the paper, we infer several fine-grain channel characteristics useful to feed further research work in the area of LTE MIMO. As a second contribution of the paper, we analyze the performance of classical schedulers (i.e., Round Robin, Best CQI and Proportional Fair) under the obtained LTE MIMO channel conditions. Specifically, we analyze the impact of the channel feedback reporting rate in scenarios with multiple greedy sources.

ABSTRACT
IP Multimedia Subsystem (IMS) is becoming the prevailing candidate for managing future mobile multimedia communications, including critical communications such as public safety, emergency professionals and corporate networks. IMS security and privacy has gained much attention in the few last years. The review of recent IMS security activities stresses the inclusion of intermediate nodes in the media path of secured communications as an open issue. This paper presents an end-to-middle-to-end solution which enables the usage of IMS media plane elements such as recorders, transcoders and novel cross-ciphering functions in a secure way. The proposed solution, which is fully compliant with IMS, includes the network architecture, the signaling plane for session signaling and key management, and the media-plane security characteristics. Experimental results demonstrate that the proposed solution can provide media interoperability (both transcoding and cross-ciphering) with a cost of 17% overhead to a standard IMS call setup in the signaling plane.

ABSTRACT
This paper deals with the resource allocation problem aimed at maximizing users’ perception of quality in wireless channels with time-varying capacity. First of all, we model the ubjective quality-aware scheduling problem in the framework of Markovian decision processes. Then, given that the obtaining of the optimal solution of this model is unachievable, we propose a simple scheduling index rule with closed-form expression by using a methodology based on Whittle approach. Finally, we analyze the performance of the achieved scheduling proposal in several relevant scenarios, concluding that it outperforms the most popular existing resource allocation strategies.

ABSTRACT
In this paper we study how to design a scheduling strategy aimed at minimizing the average holding cost for flows with general size distribution when the feasible transmission rate of each user varies randomly over time. We employ a Whittle-index-based approach in order to achieve an opportunistic and non-anticipating size-aware scheduling index rule proposal. When the flow size distribution belongs to the Decreasing Hazard Rate class, we propose the so-called Attained Service Potential Improvement index rule, which consists in giving priority to the flows with the highest ratio between the current attained service-dependent completion probability and the expected potential improvement of this completion probability. We further analyze the performance of the proposed scheduler, concluding that it outperforms well-known opportunistic disciplines.

ABSTRACT
This paper deals with the analysis of mobile multimedia services, with special focus on current media resolutions for mobile handsets. Since variable network conditions entail variable quality levels, nowadays several applications implement some kind of dynamic service adaptation in order to mitigate these effects. This paper analyzes the service performance from an end-to-end perspective, taking into account the several agents involved in the service provision. From a detailed study, the different possible sources of degradations are identified as well as their impact into the expected quality as perceived by end users. Based on the obtained results, the possible effects of different adaptation capabilities are discussed. The identification of the main source of degradations at the destination endpoint improves the adaptation capabilities and enhances the service performance in terms of perceived quality.

ABSTRACT
Most multimedia applications implement some kind of packet losses analysis mechanism to trigger self–adaptation actions. However, error recovery mechanisms such as ARQ variants avoid packet losses at IP level. Then, there appears an impact into the delay that may indeed result on application–level losses due to samples arriving later than the scheduled playout time. In most cases such degradations are not detected until they are so severe than even losses at IP level appear. We propose a lightweight method that achieves a finer grain estimation. We prove mathematically the capability of modified versions of statistics of delay to predict the error ratio of the wireless link and the load of the wired backhaul. After deducing also simplified heuristics for proposed method, we analyze their estimation capabilities and provide guidance for selecting appropiate parameters.

ABSTRACT
This paper deals with the subjective quality maximization problem when scheduling multimedia traffic flows in a shared channel. In order to quantify such user satisfaction a utility function dependent on flow transfer delay is used. In this context, we formulate the Quality of Experience aware resource allocation optimization problem as a Markov Decision Process. This model is analytically unsolvable in general, and as an approximate solution we develop a simple and tractable index rule based on Gittins approach, originally aimed just at minimizing mean flow delay. As concluded from simulation results, when evaluating subjective quality performance this novel index rule proposal outperforms the most relevant existing scheduling disciplines.

ABSTRACT
A major issue in the application of ad hoc networking to Wireless Networked Robotics is the choice of the routing protocol that performs better in a given scenario. However, far too little attention has been paid to routing issues involving enhanced robotic nodes. In view of the lack of a significant and comprehensive analysis, this research work completes an in-depth performance comparison of mostly well-known ad hoc routing protocols under a wide variety of conditions and applies the obtained results to a case study with three examples of real-world Wireless Networked Robotics scenarios.

ABSTRACT
Scalable video coding allows an efficient provision of video services at different quality levels with different energy demands. In order to deal with the resulting trade-off we analyze the number of video layers that are worth to be received taking into account the energy constraints. On one hand, a single-objective optimization is proposed based on dynamically selecting the number of layers, which is able to minimize the energy consumption with the constraint of a minimal quality threshold to be reached. However, this approach cannot reflect the fact that the same increment of energy consumption may result on different increments of visual quality. Thus, a multi-objective optimization is proposed and a utility function defined in order to weight the energy consumption and the visual quality criteria. Finally, since the optimization solving mechanism is computationally expensive to be implemented in mobile devices, a heuristic algorithm is proposed. This way mobile operators and end users could significally reduce their energy consumption while keeping reasonable quality levels.

ABSTRACT
This paper deals with the problem of scheduling mobile Internet traffic over a single cell wireless downlink data channel. On the one hand, we compare the performance of different size-based or/and channel-aware scheduling disciplines in mean delay terms, concluding that an approach that combines both size- and channel-awareness is the best alternative, which guarantees acceptable uplink overhead due to channel information reports. On the other hand, we study the impact of different scheduling algorithms on user's satisfaction for web browsing service. As concluded, in order to achieve a trade-off between maximizing overall mean subjective quality and reducing uplink signaling overhead due to channel quality reports, a scheduling policy that benefits from opportunistic gains in combination with a size-aware tie-breaking rule gives the best results.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and a mobile UMTS network is considered for the access to services. First, from subjective tests results, the combined impact of different service- and radio network-level parameters is inferred. As a result, different cross-layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions. Afterwards, the backhaul segment is considered taking into account possible congestion effects after the aggregation of multi-user media stream. The proposed dynamic adaptation process determines the best combination of media bitrates in order to optimise the overall quality, by making use of information related to network performance both at the radio and backhaul segments.

ABSTRACT
The main scope of the chapter is to present the overall QoE-driven IPTV architecture and the respective perceptual benchmarking of it via a subjective evaluation procedure. The chapter is organized as follows: Section 15.2 presents an overview of all the core components of the adaptive IPTV system (IMS, QoE, Perceptual Cross layer adaptation, network management, etc.). In Section 15.3, the user-centric IPTV architecture is presented, containing NQoS to PQoS mapping operations, the Multimedia Content Management System, the monitoring and adaptation modules presentation, the enhancements of the current IMS functions, and UMTS/ WiMAX technologies QoE/QoS mapping. Section 15.4 analyzes in depth the QoE model used for IPTV cross-layer adaptation. Section 15.5 concludes the benchmarking of the whole architecture, and finally Section 15.6 draws the conclusions.

ABSTRACT
In this paper, we consider mobile multimedia services delivered over a UMTS network. In this convergent scenario, low level error recovery mechanisms of the access network entail that almost all packet losses are caused by frames arriving at the receiver later than the playout time. Our aim is to find a simplified yet realistic expression for the statistics of the end–to–end delay in order to characterize related application level losses and infer resulting Quality of Experience (QoE). We present a simple and easy to implement model based on empirically obtained parameters that quantitatively reflects the statistical properties of delay. We apply the model to estimate the behavior of application level losses and delay which are the key factors while forecasting QoE in VoIP. Obtained results prove the suitability of the model to be integrated in cross–layer adaptation mechanisms and its utility for dimensioning VoIP playout buffers is also tested.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service– and network–level parameters is inferred. As a result, different cross–layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions.

ABSTRACT
The inclusion of multimedia content in different web-based services has increased significantly. Through an extensive subjective testing campaign, we analyse the quality of experience concerning video transmissions associated to these types of services when accessed from mobile devices and mobile Internet connections. Contrary to traditional normalised quality assessment studies, we point out the service context as a key aspect in quality assessments. Specifically, we analyse the impact of the duration of the test material on quality assessments. We find out that tolerance to visual degradations is higher in the specific context of use compared to when using standardised methodologies for quality assessment, which has a significant impact in terms of commercial service acceptability.

ABSTRACT
This chapter proposes a Content-aware and Network-aware Management System (CNMS) over a converged user-environment of social networking and mobile multimedia. The proposed CNMS will focus on applying dynamic personalized multi-layer adaptation for the optimization of the Quality of Experience (QoE) level in a requested media service according to the users’ preferences, favourites provided in their social network profile, and prior experiences rated by users themselves. By user’s preference extraction, a service/content classification will be performed according to an estimation of the user’s favourites, which will be used to provide optimized media delivery across the delivery chain. Therefore, the end-user will always receive her/his favourite service, like Internet Protocol Television (IPTV), Voice over Internet Protocol (VoIP), interactive application/on-line gaming, web browsing, at requested QoE. The system will ensure optimal allocation of network resources and optimal selection of streaming scheme according to different services/content types and user preferences, and therefore enhance the ratio of price-for-value for the specific subscription and achieve an end-to-end, holistic QoE optimisation. Although QoE is perceived as subjective, it is the only measure that counts for customers of a service. Being able to estimate the user preferences in a controlled manner through the end-user’s social networks profiles, helps operators understand what may be wrong with their services and their respective QoE. The proposed multimodal management system is user-centric and applies advanced machine learning techniques in order to extract user preferences from the social network profile of the user and build up a ranking scale of the services/contents. This ranking scale will be translated to adaptation actions per service type at several instances such as before the provision of the service takes place (i.e. Time Zero), during the delivering of the service (i.e. Time T), across all the network layers and delivery-chain nodes, while ensuring throughout the process that the main focus on the QoS-adaptation of the mobile access network is maintained.

ABSTRACT
The aim of this paper is to present video quality prediction models for objective non-intrusive, prediction of H.264 encoded video for all content types combining parameters both in the physical and application layer over Universal Mobile Telecommunication Systems (UMTS) networks. In order to characterize the Quality of Service (QoS) level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) and a second model based on non-linear regression analysis is proposed to predict the video quality in terms of the Mean Opinion Score (MOS). The objective of the paper is two-fold. First, to find the impact of QoS parameters on end-to-end video quality for H.264 encoded video. Second, to develop learning models based on ANFIS and non-linear regression analysis to predict video quality over UMTS networks by considering the impact of radio link loss models. The loss models considered are 2-state Markov models. Both the models are trained with a combination of physical and application layer parameters and validated with unseen dataset. Preliminary results show that good prediction accuracy was obtained from both the models. The work should help in the development of a reference-free video prediction model and QoS control methods for video over UMTS networks.

ABSTRACT
The growth of emerging multimedia applications with different quality requirements has made the objective network QoS (NQoS) to be commonly considered as an inadequate metric for quality assessment in telecommunication services, being the quality of experience (QoE) concept the most predominant alternative. However, most QoE-related research studies are service-specific, not easily expandable to other multimedia services and unsuitable for tuning up network management procedures. Instead, we propose an integrated QoE management model and a calculus process that estimates final user-satisfaction over multi-service scenarios and identifies those elements that have a greater impact on users' QoE. In order to evaluate this impact, new VoIP and video perception assessment methods were developed, while state-of-the-art methods were used for web and online game services. The effectiveness of the model is demonstrated by applying a stepwise multiple linear regression method to identify both subjective and objective bottlenecks in the network.

ABSTRACT
Most of the currently available adaptation solutions of VoIP over UMTS are based on the modification of service parameters as the only available reaction against any detected service degradation. On the contrary, in this paper we propose a combined approach where service-level adaptation is considered first and, provided that no suitable parameter combination is capable of providing enough QoE, a change of network state will be suggested. In order to do so we analyze the performance of the end-to-end (e2e) performance metrics in this convergent scenario, the root causes of possible degradations and, finally, the combined effects of the different network segments and their impact on the user perceived QoE. We show the map of best performing VoIP configurations for every state of the network segments. Furthermore, considering each of these configurations, we analyze the acceptability of the service or the convenience of trying to modify the network state. Finally, a lightweight implementation based on simple network state estimation and decision heuristics is proposed and validated in terms of accuracy and responsiveness.

ABSTRACT
The advent and rise of broadband technologies and new applications and services have led to a complex heterogeneous scenario in which providing Quality of Service (QoS) has become a compelling issue. Furthermore, the competitive condition of the telecommunications environment has caused user’s perception of quality to become one of the most differential factors for service providers. Due to this fact, QoS must not only attend to specific technical metrics, but more important, QoS criteria should be defined to assure the level of quality to fulfil the users’ requirements. In this new context, the definition of effective user-oriented QoS management models and frameworks has become a matter of contention. This chapter aims to provide readers a comprehensive analysis of the entire significance of a user-centered approach for quality of service management. For this purpose, a review of the most important issues related to the subject is provided.

ABSTRACT
Quality of service has become one of the most important factors among Internet service providers. The implementation of appropriate QoS policies is essential in order to maintain customer loyalty and fulfill regulators' requirements. ITU-T recommendation E.802 provides a framework for the identification of QoS criteria relevant to users and ISPs. This Recommendation also provides guidelines to derive measurable QoS parameters from identified criteria. This article presents a QoS management model and implementation methodology for ISPs. We ground our investigation on the E.802 framework, which ISPs may face when implementing ITU-T Recommendation G.1000. The proposed methodology is meaningful for users, vendors, and network operators. Furthermore, its conformance with the ITU-T standard makes it suitable and deployment-ready for both regulators and providers.

ABSTRACT
Future Internet will have to cope with yet unknown terminals and services (even users), in a number and heterogeneity never seen before. So, flexibility or adaptability will be considered as one of the most important design principles. This flexibility will demand different kinds of awareness both in the ends and in every node in the service supplying chain, while targeting users' satisfaction as the final goal of any management process. Although virtualization and “everything is a service” approaches seem to be promising foundations to guarantee this flexibility, Future Internet will be built upon real world mobile wireless network technologies, so that cross-layers issues and quality constraints will persist. Quality of Experience (QoE) could play a significant role there, since it could provide an unified metric, isolating users from low level details or complex NQoS definitions. We will also show an example of how user-aware network tuning mechanisms are able to provide similar users' QoE with lower resources consumption and therefore propose that QoE and *-awareness were considered in the Future Internet design from the very beginning.

ABSTRACT
The concept of PQoS, although in general it deals with the user satisfaction with a specific delivered/ requested service, is in practice significantly differentiated by the nature of each delivered service. This chapter reviews various existing PQoS assessment methods for video, VoIP, online games, and Web services that have been published in the literature. It then moves beyond the current PQoS assessment methods and presents novel techniques for predicting the PQoS of a multimedia service.

ABSTRACT
This chapter introduces the principal characteristics of MANETs and shows how these particularities may affect both QoS conditions and QoS management/provisioning systems, and therefore the capabilities of MANETs for properly providing multimedia services. After a deep analysis of different QoS mechanisms at different layers, the authors claim that QoS management cannot be handled only at the network layer or by applying some QoS-aware routing protocols. In fact, any end-to-end QoS provision architecture will demand QoS control mechanisms and information exchange among all the layers. A clear understanding of different proposals aimed at coping with QoS requirements at different layers will not only provide researchers with valuable information for designing better multimedia capable MANETs, but will also assist them in evaluating the need for a unified cross-layer approach in order to optimize the performance of analyzed protocols.

ABSTRACT
IMS entails novel business opportunities for pioneering and emerging multimedia services, such as IPTV and VoIP video call applications. However, this strong commercial interest on this promising convergent IMS environment is balanced by the lack of efficient user/customer-centric network management mechanisms. ADAMANTIUM proposes an IMS-compatible Multimedia Content Management System (MCMS) focused on performing dynamic cross layer adaptations for ptimization of the user experience in terms of perceptual quality for media services. This multimodal management system will be applied in an integrated and coherent way along all the network layers and delivery-chain nodes based on a user/customer-centric approach rather than a typical engineering one.

ABSTRACT
Simulation models have been developed in order to foresee characteristics of networks, systems or protocols when carrying out tests in laboratories is very expensive or even impossible. This paper presents a simulation model of a multiprocessor network traffic analysis system. The model, which is based on closed networks of queues, evaluates the efficiency of the system depending on the hardware/software platform features. Therefore, this model is able to estimate performance early in the design and development stages simulating a multiprocessor architecture in charge of analysing network traffic. The goodness of the model will be checked by comparing analytical results with practical ones obtained in laboratory using a traffic analysis system that runs on a multiprocessor platform.

ABSTRACT
This paper analyzes different techniques to implement Quality of service (QoS) on multi-tenant 5G networks. Describes the architecture of the next generation mobile network based on cloud-enabled small cell deployments and also proposes an hybrid-cloud solution coexisting with centralized cloud RAN (C-RAN), in order to achieve a gradual implementation of the technology. In this context, the work here presented deals with the challenges of preserving the quality of experience in a multi-tenant cloud enable RAN bearing in mind the Key Performance Indicator (KPI) agreed in the Service Level Agreement (SLA). To achieve this goal, QoS should be managed at different levels of the architecture. Feedback should be given between learning modules in order to analyze the results and infer enhanced decision rules which may conclude in an architecture replacement.

ABSTRACT
This paper focuses on multi-tenant 5G networks with virtualization and mobile edge computing capabilities, in the scope of cloud-enabled small cell deployments. In this context, the work here presented deals with the service management and orchestration challenges that arise when handling service mapping on the multi-tenant distributed cloud-enabled radio access network architecture. For that aim, once analysed cloud edge services management and 5G network instantiation in the OpenStack platform, we modify the provided virtual infrastructure manager so as to incorporate virtual network function placement features of the SESAME environment. As main contributions, we adapt the OpenStack application instances to 5G Network Service instantiation, and we include an energy-aware and latency-constrained placement solution.

ABSTRACT
This paper aims at increasing our understanding of the behaviour of some of the major TCP variants in LTE networks. A simulation study on the behaviour of seven TCP variants is performed. The evolution of the throughput, congestion window and queuing delay are studied for four scenarios with different network loads and flow types. Our measurements show that, in average radio conditions, most variants are able to quickly reach full link utilisation. However, to achieve the same throughput, they create different amounts of queuing delay. On the one hand, loss-based algorithms tend to completely fill the queue, creating huge queuing delays and inducing packet losses. On the other hand, delay-based variants manage to limit the queue size and decrease the amount of packets dropped by the eNodeB, but struggle to reach the maximum throughput in some circumstances.

ABSTRACT
The proper execution of performance tests is of utmost importance for the analysis and evaluation of Internet-related technologies, protocols and deployment strategies. Nowadays, there are plenty of tools available to experimenters ranging from simulation tools, emulation equipment, to small and large scale experimentation testbeds. Each of these performance evaluation frameworks introduces a series of capabilities and drawbacks. Additionally, there is a need for using a common methodology to perform different performance tests and to create comparable outcomes. Seeking for the standardization of reliable and comparable Internet speed measurements and trying to provide end-users with trustworthy measurement tools, different SDOs have standardized both TCP-based and IP-based measurement methodologies. This paper focuses on the applicability of the different measurement frameworks and methodologies in the field of mobile Internet, with special focus on the impact of using TCP over mobile broadband connections. The paper describes a series of experiments over different frameworks and, based on the obtained results, identifies the implications of the different types of performance tests into the evaluation outcomes and states the need for large scale measurements.

ABSTRACT
The Cloud Enabled Small Cell (CESC) concept proposed in EU funded project SESAME has emerged as a promising solution to form a multi-tenant, multi-service architecture at the network edge according to 5G needs. It allows several operators/service providers to engage in a sharing model of both radio access capacity and Mobile Edge Computing (MEC) capabilities. From a business perspective, the shared ecosystem guarantees benefits such as easy system upgrades and CAPEX/OPEX reduction. However, depending on the adapted model which is reflected at Service Level Agreement (SLA) between involved stakeholders, cost and benefit of each party are subject to change. This paper is an effort to identify and analyse different radio and cloud models and pricing schemes for the joint provisioning of radio access capacity and MEC services in a multi-tenant Radio Access Network (RAN).

ABSTRACT
Adding cognitive capabilities to the wireless networks makes it possible to leverage the control and management information used in the network operation to infer information about the local state and exploit it to improve the overall performance. This paper deals with the combined use of centralized and distributed cognitive cycles integrated at different planes in 5G networks: an integrated data plane, a unified control plane and a cross-layer management plane. This context-aware cognitive schema acts on the decision making modules depending on the monitored environment to prevent failures, balance the virtualized execution and get a global enhancement in the provision of mobile services. The multi-level cognitive cycle supports the interaction between the edge and the cloud blurring the line that separates two paradigms: centralized radio operation and mobile edge services.

ABSTRACT
Mobile internet has been widely adopted and it is expected to rise to almost 4 billion users by 2020. Despite the research effort dedicated to the enhancement of its performance, there still exists a gap in the understanding of how TCP and its many variants work over LTE. To this end, this paper evaluates the extent to which five common TCP variants, CUBIC, NewReno, Westwood+, Illinois, and CAIA Delay Gradient (CDG), are able to utilise available radio resources under hard conditions, such as during start-up and in mobile scenarios at different speeds. The paper suggests that CUBIC, due to its Hybrid Slow-Start mechanism, enters congestion avoidance prematurely, and thus experiences a prolonged start-up phase. As a result, it is unable to efficiently utilise radio resources during shorter transmission sessions. Besides, CUBIC, Illinois and NewReno, i.e., the loss-based TCP implementations, offer better throughput, and are able to better utilise available resources during mobility than Westwood+ and CDG – the delay-based variants do.

ABSTRACT
After several years of research towards sophisticated QoS measurement tools and methods, the results given to end-users by most commonly used on-line speed measurement tools are still far from being precise. In order to define a reliable Internet speed measurement methodology for end- users, the impact that the static and dynamic constraints of network nodes and TCP/IP implementations could impose must be first carefully analyzed. Such constraints will deter- mine the measurement methodology to be defined in terms of measurement periods, number of concurrent connections and convergence time by deployment of controlled simula- tion/emulation environments and real world comparisons. This paper presents a detailed description of the works and leaves hints to be followed, aiming to get a full understanding of cross-layer effects during a speed test targeting end-user.

ABSTRACT
The evolution of Internet access technologies, together with the wide diversity of customer devices, has led to a complex scenario where measuring basic metrics with accuracy has become a rather complicated task. Although nowadays there are a lot of tools to assess the rate of Internet speed, most of them share neither the methodology nor the infrastructure to produce comparable results.

In this regard, the development of a unified approach to measure the Internet speed would be beneficial for all ICT players. The establishment of such proposal would inspire better confidence in consumers through the provision of precise comparisons, and it would also be very useful to operators, regulators and providers. Towards this aim, the ITU-T has been working on the definition of a unified methodology and measurement framework to assess the rate of Internet speed.

This paper presents a detailed description of the work that is being done at present in the definition of the aforementioned framework.

ABSTRACT
Este artículo trata sobre los esquemas de distribución de contenido multimedia a través de Internet, con especial interés en Internet móvil. Tanto la variabilidad de la calidad de los accesos radio como el incremento del tráfico multimedia plantean nuevos retos en relación a la gestión dinámica de los servicios sobre recursos de red compartidos. En primer lugar, el artículo ofrece una revisión del estado de la tecnología relacionada con el transporte multimedia extremo a extremo. A continuación, el artículo se centra en analizar la evolución de los mecanismos de adaptación dinámica, incluyendo desde esquemas extremo a extremo hasta la gestión dinámica de los recursos de red. Se analizan las posibles ventajas asociadas a nuevas arquitecturas como la computación en la nube móvil y las futuras redes 5G. Finalmente, el artículo identifica una serie de retos y desafíos en la gestión adaptativa de los servicios multimedia en el futuro.

ABSTRACT
Radio Resource Management (RRM) function is a critical element in multi-user mobile networks. Nowadays, RRM is implemented at the 4G radio edge in order to enhance channelawareness and thus to optimize the efficiency of radio resources, at the cost of high computational requirements at the radio nodes. Current trends towards Network Function Virtualization aim at enabling software-based networking capabilities at different locations of the radio network architecture. This paper analyzes the impact of moving RRM functions to different Radio Access Network locations and with different channel quality feedback periods. Based on simulation results, the paper analyzes the experienced performance of different channel-aware scheduling strategies in the context of multi-user mobile multimedia scenarios with different radio channel conditions.

ABSTRACT
One of the most challenging problems in mobile broadband networks is how to assign the available radio resources among the different mobile users. Traditionally, research proposals are either specific to some type of traffic or deal with computationally intensive algorithms aimed at optimizing the delivery of general purpose traffic. Consequently, commercial networks do not incorporate these mechanisms due to the limited hardware resources at the mobile edge. Emerging 5G architectures introduce cloud computing principles to add flexible computational resources to Radio Access Networks. This paper makes use of the Mobile Edge Computing concepts to introduce a new element, denoted as Mobile Edge Scheduler, aimed at minimizing the mean delay of general traffic flows in the LTE downlink. This element runs close to the eNodeB element and implements a novel flow-aware and channel-aware scheduling policy in order to accommodate the transmissions to the available channel quality of end users.

ABSTRACT
This work deals with the problem of scheduling traffic flows in emerging wireless networks. In actual mobile implementations the channel state feedback from the users to the radio schedulers may be deployed based on periodic reports in order to avoid uplink signaling overhead. In this work, we study how to design schedulers under partially observable channels. For that aim, we employ the Whittle index approach using a Partially Observable Markov Decision Process. We further analyze the performance of the derived scheduling solution, both in single-class and multi-class scenarios. Real-world channel quality traces are employed in experiments. Finally, we conclude that the proposed scheduling index rule outperforms well-known channelaware disciplines.

ABSTRACT
This paper deals with the classical problem of radio resource management in LTE MIMO, with special focus to the specific radio channel characteristics in commercial LTE networks. First, we provide some conclusions about the Channel Quality Information traces obtained through field testing. From this analysis, we perform a series of experiments by means of an LTE emulator in order to evaluate the accuracy of different fading models used in the 3GPP. As a first outcome of the paper, we infer several fine-grain channel characteristics useful to feed further research work in the area of LTE MIMO. As a second contribution of the paper, we analyze the performance of classical schedulers (i.e., Round Robin, Best CQI and Proportional Fair) under the obtained LTE MIMO channel conditions. Specifically, we analyze the impact of the channel feedback reporting rate in scenarios with multiple greedy sources.

ABSTRACT
In this paper we study how to design a scheduling strategy aimed at minimizing the average holding cost for flows with general size distribution when the feasible transmission rate of each user varies randomly over time. We employ a Whittle-index-based approach in order to achieve an opportunistic and non-anticipating size-aware scheduling index rule proposal. When the flow size distribution belongs to the Decreasing Hazard Rate class, we propose the so-called Attained Service Potential Improvement index rule, which consists in giving priority to the flows with the highest ratio between the current attained service- dependent completion probability and the expected potential improvement of this completion probability. We further analyze the performance of the proposed scheduler, concluding that it outperforms well-known opportunistic disciplines.

ABSTRACT
In this paper we study how to design an opportunistic scheduler when flow sizes have a general service time distribution with the objective of minimizing the expected holding cost. We allow the channel condition to have two states which in particular covers the important special case of ON/OFF channels. We formulate the problem as a multi-armed restless bandit problem, a particular class of Markov decision processes. Since an exact solution is out of reach, we characterize in closed-form the Whittle index, which allows us to define a heuristic scheduling rule for the problem. We then particularize the index to the important subclass of distributions with a decreasing hazard rate. We finally evaluate the performance of the proposed Whittleindex based scheduler by simulation of a wireless network. The numerical results show that the performance of the proposed scheduler is very satisfactory.

ABSTRACT
Nowadays there is a growing uncertainty about the near future evolution of classical PMR solutions due to spectrum scarcity, digital dividend issues and economic crisis. This paper aims at facing this situation by seizing the existing window of opportunity due to the convergence of the IMS as a predominant enabler for future multimedia networks and the deployment of commercial LTE networks. The paper details an innovative emergency inter-networking system capable of connecting existing first responder communication systems and enabling the integration of next generation mobile networks by defining technology independent standardized interfaces under the umbrella of IMS. Concerning the experimental outcomes, the paper focuses on the reference implementation to interface with the proposed system.

ABSTRACT
Nowadays, the Critical Communications networks are experiencing the transformation that will lay the foundations for next decades of emergency communications. Although different forums claim for the benefits of different technological solutions, this evolution seems to be driven towards the adoption of commercial radio technologies and mass market devices. Although new standards are being developed by different standardization organizations, the concept of interoperability between Public Safety organizations as a holistic standpoint is still an open issue standards should address in the near future. This paper analyzes the current trends in next generation Critical Communications, and reviews the different efforts carried out by different standardization organizations. It is shown that, although different aspects of interoperability are addressed, an integral interoperability framework is needed. Additionally, the specific area of Operation and Management is discussed as one of the missing pieces. A series of system requirements and design principles are finally provided.

ABSTRACT
This paper deals with the performance evaluation of deploying an IMS-based media plane interoperability framework. The 3GPP standards describe two possible operating modes based on either a reactive or a proactive approach. We show that both approaches entail some advantages and drawbacks in terms of signaling overhead and call setup times. In order to use experimental individual delay contributions, a prototype implementation of the required elements was carried out for which transmission and processing times and the average ratio of incompatible calls where evaluated. Additionally, the evaluation focuses on the impact of deploying the interoperability solutions over current UMTS and LTE radio access networks.

ABSTRACT
This paper analyzes the scenario where multiple users are trying to transmit the same or related content to a common destination through a shared radio access network. A specific aspect of this study is that all users work for a common objective, as it would be the transmission of critical emergency-related media contents to a central operator. We analyze the performance achievable using an LTE cell, with different client-driven autonomous adaptation strategies that take both the network performance and the battery status as input parameters. Remarkable performance results are achieved in terms of number of acceptable uplink video streams in different simulation scenarios. The work would help for designing context- and network-aware adaptation schemes for emergency mobile applications.

ABSTRACT
Emergency telecommunication systems play an important role in people’s daily life, supporting communication for the public and first responders during emergency related incidents. Nonetheless, the majority of existing emergency communications are limited to traditional voice and text message services due to the data bandwidth constraint of current networks. It is well known that emerging 4G broadband communication technologies have the ability to provide a range of multimedia services (e.g. picture transmission) that could be utilised by the emergency services to save lives. However, a secured emergency conversation cannot be established between incompatible mobile/end devices without the assistance of a security gateway. Therefore, this paper proposes a technology independent security gateway that provides security support for future emergency telecommunication systems. The proposed security gateway works in three modes to cover all the situations in which its assistance is required to establish a secured emergency conversation. In addition, the development process of the security gateway will also be fully discussed in this paper.

ABSTRACT
The great technological evolution achieved in the field of public communication networks in comparison to the slower pace of the critical communications sector has raised discussions regarding the next evolutionary steps of PMR technologies and the integration of mission critical aspects into public wideband networks. This paper analyses a converged scenario of the public and private mobile network technologies which will enable those professionals to make the most of both worlds, while assuring efficient use of critical resources. This paper provides a short overview of the principles that derive from end-user requirements along with a system applicability analysis in a number of complete use cases.

ABSTRACT
Currently, the critical communications sector is aware of the need for evolving the portfolio of service capabilities to support advanced multimedia communications in their daily emergency operations. However, there is a discussion about the evolving the private communication networks or adopting commercial network technologies, which have evolved significantly during the last years. This paper presents a process of interaction with critical communication professionals belonging in different professional sectors, different countries and different user profiles. This paper gathers the main findings of this interaction in terms of captured users’ requirements for novel services to be adopted and types of networks which shall support them.

ABSTRACT
This paper presents a novel open-source implementation of a call center, which is compatible with the IP Multimedia Subsystem (IMS) platform, supporting call forwarding and dispatching services, along with video call and chat with file transfer. The proposed solution is called Call Center for IMS (CC4IMS) and following a requirement analysis, the paper discusses the overall architecture and design of the proposed Call Center, focusing on the IMS compatibility and mobility of the implementation. Then, an open-source prototype implementation is presented, which was designed for mobile devices in order to be suitable for distributed and ad-hoc launch at emergency situations by first responder teams near to the location of the emergency incident. Finally, a protocol and message illustration between the CC4IMS and the IMS modules is presented, based on messages that have been actually captured by the CC4IMS prototype and the Open IMS Core, showing that the proposed Call Center confronts with the IMS signaling.

ABSTRACT
This paper deals with the analysis of the impact of different scheduling algorithms on flow level mean delay performance of elastic traffic in a single cell wireless downlink data channel paradigm. An enhanced size-based and channelaware discipline is proposed, which is based on the sized-aware Gittins index approach applied to a time-varying channel context. In order to compare the proposed Opportunistic Gittins rule performance with well-known scheduling algorithms, several simulations have been performed for stochastically arriving flows with Pareto sizes under fading conditions, for different network loads and channel quality indicator reporting rates. As concluded, an approach that combines both flow size-awareness and channel awareness is the best option, which guarantees a trade–off between minimizing uplink overhead due to channel quality reports and improving scheduling performance aimed at reducing overall flow mean delay.

ABSTRACT
The aim of this paper is to assess the impact of devices on Quality of Experience (QoE) of the user. As the types of video content viewed over handheld devices increases e.g. streaming video, it is important to evaluate the impact of the end device on video quality assessment. In this paper subjective tests were conducted with QCIF (176x144) videos over two devices 6 Personal Computer (PC) and mobile handset with 90 test conditions. The dataset was generated with a combination of parameters associated with the access network (block error rates and mean burst lengths), H.264 codec related parameter (sender bitrates) and content types. Subjects favoured PC test over handset test in almost all test scenarios. It was found that as the content activity increases device matters. These studies should help in context-aware services in deciding the encoding parameters based on type of device being used to receive content.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for broadcast mobile TV services, considering energy constraints of mobile devices. A new broadcast multilayering video transmission scheme is proposed to cope with the heterogeneity of mobile devices capabilities, which enables mobile devices to achieve energy savings in accordance to the received visual quality. This new scheme includes audio transmission and still guarantees an acceptable channel switching delay. From subjective tests results, the impact of different service parameters is inferred. As concluded, an approach based on the fine tuning of video layer number and spatial resolution provides the highest achievable QoE level. An advanced decision making process is required to combine both QoE–awareness and energy–awareness.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service- and network-level parameters is inferred. As a result, different cross-layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions.

ABSTRACT
In this paper, we consider mobile multimedia services delivered over a UMTS network. In this convergent scenario, low level error recovery mechanisms of the access network entail that almost all packet losses are caused by frames arriving at the receiver later than the playout time. Our aim is to find a simplified yet realistic expression for the statistics of the end-to-end delay in order to characterize related application level losses and infer resulting Quality of Experience (QoE). We present a simple and easy to implement model based on empirically obtained parameters that quantitatively reflects the statistical properties of delay. We apply the model to estimate the behavior of application level losses and delay which are the key factors while forecasting QoE in VoIP. Obtained results prove the suitability of the model to be integrated in cross-layer adaptation mechanisms and its utility for dimensioning VoIP playout buffers is also tested.

ABSTRACT
The evolution of current networks to Next Generation Networks (NGNs) constitutes arguably the most significant transformation in the Telecommunication sector in recent decades. Quality of Service (QoS) is one of the key aspects in this evolution. In the NGN environment, networks are designed to be multiservice, supporting a wide range of premium services. Each of these services may have different QoS requirements which should be established based on the overall end user's perception. In this emerging context, novel QoS policies are required to adapt the traditional QoS regulatory model to the new scenario. This paper presents an approach to identify key factors that contributes to the development of future Internet quality of service regulation. A case study on the application of our user-centric QoS model to the Internet QoS regulation in Spain is described. The results of the study demonstrate the need for adapting current regulatory frameworks in order to ensure competition, pluralism and diversity in the new network environment.

ABSTRACT
In Universal Mobile Telecommunication System (UMTS) Radio Link Control (RLC) losses severely affect the Quality of Service (QoS) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour. In this paper we evaluate the impact of the radio access network on the end-to-end QoS for H.264 encoded video. In order to characterize the QoS level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) is proposed that takes into account the RLC loss models to predict the video quality in terms of the Mean Opinion Score (MOS). The RLC loss models considered are 2-state Markov models with variable mean burst lengths. The aim of the paper is two-fold. First, to find the impact of QoS parameters in both the physical and application layer on end-to-end video quality. Second, to propose a prediction model based on ANFIS to predict video quality over UMTS networks. ANFIS is well suited for video quality prediction over error prone and bandwidth restricted UMTS as it combines the advantages of neural networks and fuzzy systems. The ANFIS model is trained with a combination of application and physical layer parameters. The performance of the proposed model is validated with unseen dataset. These studies should help in the understanding of the impact of both the application and physical layer parameters on end-to-end video quality and in QoS control methods and adaptation.

ABSTRACT
The Quality of Service (QoS) of Universal Mobile Telecommunication System (UMTS) is severely affected by the losses occurring in Radio Link Control (RLC) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour appropriately. In addition, video content has an impact on video quality under same network conditions. The aim of this paper is to present video quality prediction models for objective, non-intrusive prediction of H.264 encoded video for all content types combining parameters both in the physical and application layer over UMTS networks. In order to characterize the QoS level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) is proposed to predict the video quality in terms of the Mean Opinion Score (MOS). ANFIS is well suited for video quality prediction over error prone and bandwidth restricted UMTS as it combines the advantages of neural networks and fuzzy systems. The loss models considered are 2-state Markov models with variable Mean Burst Lengths (MBLs) depicting the various UMTS scenarios. The proposed model is trained with a combination of physical and application layer parameters and validated with unseen dataset. Preliminary results show that good prediction accuracy was obtained from the model. The work should help in the development of a reference-free video prediction model and Quality of Service (QoS) control methods for video over UMTS networks.

ABSTRACT
Universal Mobile Telecommunication System (UMTS) is a third generation mobile communication systems that supports wireless wideband multimedia applications. The objective of this paper is to present a new model for non-intrusive prediction of H.264 encoded video quality over UMTS networks and to illustrate their application to video quality monitoring and adaptation in mobile wireless streaming services. First, we present an efficient regression model for predicting video quality non-intrusively for all content types. The model is predicted from a combination of a set of objective parameters in the application and physical layer in terms of the Mean opinion Score (MOS). The application layer parameters considered are the content type, sender bitrate and frame rate and the physical layer parameters are the block error rate modeled with 2 state Markov model for a mean burst length of 1.75. The performance of the proposed metric is evaluated with unseen dataset with good prediction accuracy. Second, we illustrate the application of the model in mobile streaming services by presenting a new Sender Bitrate (SBR) adaptation scheme at pre-encoding stage that is Quality of Experience (QoE) driven. The scheme was tested and evaluated in the NS2 based UMTS simulation network. Extensive simulation results demonstrate the effectiveness of the proposed adaptation scheme in terms of the MOS and especially at the UMTS network bottleneck access where perceived video quality is most affected. The proposed scheme was responsive to available network bandwidth and congestion and adapted the SBR accordingly maintaining acceptable quality in terms of the MOS. The proposed scheme has applications in network planning and content provisioning for network/service providers.

ABSTRACT
The provision of video streaming services over mobile data accesses is emerging as a promising service for the current and future Internet. This paper focuses on the study of H.264- based video contents over a typical 3G UMTS connectivity. The performance of the service is finally determined by the combined effects of the encoding features and the radio access characteristics. Therefore, based on the UMTS channel modeling, this paper tries to find out the optimal encoding configuration that provides the best service performance, in terms of Quality of Experience. In addition to other well-known encoding parameters, such as the source target bitrate, frame rate or resolution, this paper studies the impact of the maximum video slice size as a critical parameter for the performance of the considered service.

ABSTRACT
Quality of service has become one of the most important factors among Internet service providers. The implementation of appropriate QoS policies is essential in order to maintain customer loyalty and fulfill regulators' requirements. ITU-T recommendation E.802 provides a framework for the identification of QoS criteria relevant to users and ISPs. This Recommendation also provides guidelines to derive measurable QoS parameters from identified criteria. This article presents a QoS management model and implementation methodology for ISPs. We ground our investigation on the E.802 framework, which ISPs may face when implementing ITU-T Recommendation G.1000. The proposed methodology is meaningful for users, vendors, and network operators. Furthermore, its conformance with the ITU-T standard makes it suitable and deployment-ready for both regulators and providers.

ABSTRACT
This paper evaluates the performance of VoIP services over mobile accesses, with special focus on currently deployed Best Effort UMTS networks. There are different configuration parameters that have a great impact on end users' perception of quality. This paper tries to help understanding the impact of those parameters, and how they can be tuned for a better VoIP experience.

ABSTRACT
User’s requirements have become a key factor for any Quality of Service (QoS) management model to succeed. The advent and rise of new broadband services and network architectures (Triple-Play-Services, NGN…) depends on the ability of providers to achieve user’s expectations in these scenarios. For that reason, the overall end user’s perception (Quality of Experience – QoE) must be audited, on a regular basis, to address changing user’s needs. This paper presents a general system developed to evaluate QoE on IP networks. The system architecture is designed to be capable of emulating multi agent networks and dynamically changing conditions. In addition, the results of a Web browsing QoE experiment, laid out within this emulation system, are described. The experiment was conducted on the basis of ITU-T Recommendation G.1030, and aimed to update the perceptual model, provided in this Recommendation, to today’s user requirements and technical improvements.

ABSTRACT
This paper shows the relevance of implementing a dynamic and real-time Voice over IP (VoIP) service adaptation mechanism in order to avoid Perceived Quality of Service (PQoS) degradations. We have studied the most relevant parameters affecting the PQoS experienced by end users in VoIP services over mobile accesses. We will describe the enhancements carried out in the implementation of the simulation model in order to assess VoIP PQoS based on ITU-T E-model and introduce a real-time service adaptation method. This adaptation method involves codec and packetization changes through SIP signalling, jointly to dejittering buffer management, and would be launched upon detection of PQoS degradation, in order to enhance end users' experience.

ABSTRACT
IMS entails novel business opportunities for pioneering and emerging multimedia services, such as IPTV and VoIP video call applications. However, this strong commercial interest on this promising convergent IMS environment is balanced by the lack of efficient user/customer-centric network management mechanisms. ADAMANTIUM proposes an IMS-compatible Multimedia Content Management System (MCMS) focused on performing dynamic cross layer adaptations for optimization of the user experience in terms of perceptual quality for media services. This multimodal management system will be applied in an integrated and coherent way along all the network layers and delivery-chain nodes based on a user/customer-centric approach rather than a typical engineering one.

ABSTRACT
Traffic monitoring is an increasingly important discipline for nowadays networking, as Accounting, Security and Traffic Engineering lay on it. Besides, traffic bandwidth has increased exponentially in the last few years, and high-speed network monitoring has become a challenging task. Performance requirements are highly relevant for passive QoS monitoring systems. A low-level study of the capturing and processing stages on a traffic analysis system (TAS) has shown room for improvement. We provide an architecture able to cope with high-speed traffic monitoring using commodity hardware. Our system is intended to exploit the parallelism available in up-to-date workstations, which also introduces constraints for multithreaded QoS analysis. This paper presents a kernel-level framework (ksensor) that, keeping the previous requirements, removes some issues from user-level processing and effectively integrates QoS algorithms, improving the overall performance.

ABSTRACT
Traffic monitoring is an increasingly important discipline for nowadays networking, as Accounting, Security and also Quality of Service (QoS) lay on it. Besides, traffic bandwidth has increased exponentially in the last few years, and high-speed network monitoring is a challenging aim. Performance requirements are highly relevant for monitoring systems. A low-level study of the capturing stages on a traffic analysis system (TAS) has shown room for improvement. We provide an architecture able to cope with high-speed traffic monitoring using commodity hardware. Our design is also intended to exploit the parallelism available in up-to-date workstations. This paper presents a kernel-level monitoring system (ksensor) that, keeping the previous requirements, removes some issues from user-level processing, improving the overall performance.

ABSTRACT
Traffic monitoring is an increasingly important discipline for nowadays networking, as Accounting, Security and also Quality of Service (QoS) lay on it. Besides, traffic bandwidth has increased exponentially in the last few years, and high-speed network monitoring is a challenging aim. Performance requierements are highly relevant for monitoring systems. A low-level study of the capturing stages on a traffic analysis system has shown room for improvement. We provide an architecture able to cope with high-speed traffic monitoring using commodity hardware. Our design is also intended to exploit the parallelism available in up-to-date workstations. This paper presents a kernel-level monitoring system (KSensor) that, keeping the previous requirements, removes some issues in user level monitoring system, improving the overall performance.

ABSTRACT
Deployment of quality-of-service (QoS) policies is becoming one of the biggest challenges for today's Internet Service Providers (ISPs). Nowadays, QoS does not only address specific technical standard metrics; it must be concern about other aspects such as user's final perception or regulations mandatory compliments instead. Although some efforts are being made on studying and analysing this new QoS scope, there are not still many advances on defining methodologies to deploy it on real network sceneries. UIT-T Rec. G-1000 makes an approachon this issue and provides a meaningful framework to users, service providers and regulators. Nevertheless, UIT-T G.1000 does not go an step further and remains at the 'theorical stage'. Our research group NQaS (Networking Quality and Security) is carrying out different initiatives focus on solving this new QoS dimension. This paper presents some of the on-going research areas of NQaS on the way to find an appropiate methodology to apply a global QoS policy in an ISP on the basis of the UIT-T G.1000 framework.

ABSTRACT
This work focuses on the analysis of Quality of Service (QoS) management in controlled scenarios such as corporate networks. We present a testbed based on BGP/MPLS IP VPN networks and show the QoS configuration implemented in the different nodes. The motivation of this work is to obtain stable QoS monitoring procedures that will allow us to deploy optimized QoS management mechanisms. The results are intended to represent users’ satisfaction for different networked services, so we base our QoS evaluation in perceived-QoS (PQoS) schemes. In this paper we proposed a network scenario made up of a VPN connectivity between two corporate sites. Based on the terms included in the SLA and the characteristics of different traffic profiles, we try to monitor the PQoS in different conditions, so we can obtain valuable information for a better traffic classification.

ABSTRACT
This paper presents the design of a centralized system responsible for the management of remote procedures execution in a distributed scenario. The architecture proposed will be able to unify the information provided by several services with different types of managing interfaces. In these terms, the application will catch, organize and execute procedure queries from clients in order to achieve the information by means of a common interface that will be supported by a structure of plug-ins. On the other hand, one of the objectives of the design is to describe a model for the generic definition of tasks, so that the developed system could arrange them regardless of the type of service to which they belong.

ABSTRACT
Traditional QoS related studies handle technical KPI (key performance indicators) which are supposed to measure the quality of telecommunication services. However, while trying to select an ISP, most users are not able to choice the most suitable one for their needs. This papers presents the application of a perceived QoS based model as a tool for helping users in this kind of decisions. Our model represents the impact of each one of the objective performance indicators on the perception of quality for a particular user profile. Once the model is built common users will be able to identify the best combination of performance indicators for their pattern of use of the different Internet services. We have used velocimetro.org, a website that provides measurement services for common users, in order to feed the model with real world values and compare 4 different Spanish ISPs.

ABSTRACT
This paper deals with the management of QoS as perceived by end users in corporate networks. First, we overview some previous results achieved by the research group in the field of estimating and managing the QoS. In this work we accomplished some validation tasks by means of simulation. Going on with the analysis of applicability of the general model to real-world, we propose here to analyze a network scenario that includes an MPLS IP VPN. In this scenario we can take into account all the agents involved in the provision of Internet services and moreover we can carry out a management of QoS in the network.

ABSTRACT
In last years there have been some governmental initiatives aimed at the regulation of quality of service evaluation in telecommunications services. However this has proven to be a complex task especially for Internet services, where it is difficult to objectively assess the quality of a service and to identify whether one or more of the provider agents are responsible of final dissatisfaction of users. This paper affords the cited problem and intends to provide a methodology to asses the quality of service as perceived by end users. The aims of the proposed model are twofold: the evaluation of perceived quality of service (PQoS) based on subjective and objective measurements and the identification of responsibilities of the different agents involved in a service provision.

ABSTRACT
This paper presents a comprehensive model intended to analyze quality of service in telecommunications services and its causes. Although many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns, they have not resulted in a unique methodology to assess the experienced quality. While most of the studies consider the quality of service only from a technical and end-to-end point of view, we try to analyze quality of service as a general gauge of final users' satisfaction. The proposed model allows us to estimate the quality experienced by end users, while offering detailed results regarding the responsibility of the different agents involved in the service provision. Once we overview the most significant elements of the model, an in-depth analytical study is detailed. Finally, we illustrate a practical study for web browsing service in order to validate the theoretical model.

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The importance of security issues in network environments has increased greatly lately. Intrusion Detection Systems play an important role in network security environments. Nevertheless, nowadays, data network speed is so high that performing intrusion detection tasks becomes challenging. This paper presents a software architecture that intends to exploit the parallelism available on up-to-date and future workstations to apply intrusion detection rules in high speed networks. To achieve this, a shared memory multiprocessor system has been developed. The system includes a powerful rule language that adds big flexibility to the system.

ABSTRACT
This paper presents a comprehensive model intended to analyse quality of service in telecommunications services. Many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns. However, these works have not resulted in a unique methodology to assess the experienced quality. While most of the studies consider the quality of service from biased perspectives, we try to analyse quality of service as a general gauge of final users’ satisfaction. The proposed model allows us to estimate the quality experienced by end users, while offering detailed analysis regarding the different agents involved in the service provision. Once we overview the most significant elements of the model, an in-depth analytical study is detailed. Finally, we illustrate a practical study for HTTP service in order to validate the theoretical model.

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Simulation models have been developed in order to foresee characteristics of networks, systems or protocols when doing tests in laboratories are very expensive or even impossible. This paper presents a simulation model of a multiprocessor network traffic analysis system. The model, which is based on closed networks of queues, evaluates the efficiency of the system depending on the hardware/software platform features. Therefore, this model is able to estimate performance early in the design and development stages simulating a multiprocessor architecture in charge of analysing network traffic. The goodness of the model will be checked by comparing analytical results with practical ones obtained in laboratory using a traffic analysis system that runs in a multiprocessor platform.

ABSTRACT
This paper presents a comprehensive model intended to analyse general quality in telecommunications services centred in end users’ perceived quality (PQoS). The proposed model allows us to estimate the quality experienced by end users, while offering detailed analyses regarding the responsibility of the different agents involved in the service provision. We overview the structure of the model, that resembles QFD general quality model. Then we describe a practical study where the variation of the global satisfaction of users is estimated. This approximation is carried out by means of the evaluation of a set of telecommunications services with diverse nature, such as web browsing, VoIP and even technical support. Finally, we use the multiple linear regression method for assessing different providers' contribution to the PQoS in every considered network state.

ABSTRACT
Data communication is a widespread service in our society and the need for controlling the information interchange increases. Intending to solve this need, different kind of data capture systems (sensors or probes) have been implemented. The aim of this paper is to present a new architecture that analyses data providing essential information like complex quality of service statistics, intrusion detection, accounting... Nowadays, performance requirements limit the functionalities of sensors. Therefore, we have developed a high performance multiprocessor architecture which can process passively and online the captured packets in different ways. This improvement allows to apply complex QoS algorithms whose implementation is quite difficult if the number of connections to follow is high.

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Actualmente, un aspecto clave tanto para usuarios como operadores de redes de comunicaciones es la calidad de servicio prestada en las redes de datos y servicios asociados. De hecho, según la legislación actual, los proveedores que operen en el mercado europeo pueden estar sujetos a la obligación de publicar información sobre la calidad que proporcionan. En el caso español, actualmente no existe una reglamentación al respecto, por lo que se hace necesario estudiar el conjunto de parámetros que podrían ser susceptibles de publicación por parte de estos proveedores, y los mecanismos de medida adecuados para ello.

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This paper presents an overview of the research activities accomplished in the N-QaS (Networking, Quality and Security Group) in the area of quality of service (QoS) in wireless environments and concretely in Ad HOC networks. After studying the different objective parameters that can be used to guarantee a minimum of QoS (such as: bandwidth, delay, jitter and rate of errors), and with the later study of different signalling systems for the reservation of resources (such as INSIGNIA and dRSVP), the possibility has been identified of using the period of discovery of routes from the origin to the destination (in search of the road that better responds to our necessities from the point of view of the QoS) only not thinking of the shortest road (the one that less hops offers from the origin to the destination, habitual operation from the point of view of the most routing protocols, it is not the most effective parameters in the QoS) also keeping in mind that we are allowed to be able to give priority to other parameters of QoS (objective parameters) and that they can be reserved for the whole session of communication in the same way that the route is reserved. And what is more important, this whole process would be made in parallel (at the same time), winning this way in functionality (we are fusing two necessary processes in one).

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This paper presents an overview of the research activities accomplished in the 'Telematics Engineering Group' (UPV/EHU) in the area of perceived QoS. We go over the achieved works until the current day and we present as well the scheduled research tasks regarding the measurement of QoS from an end user perspective. The proposed theoretical model is intended to analyse the performance experimented in every agent involved in the provision o f Internet services. Furthermore, we state several in-progress enhancements to the model and introduce an approach to empirically validate the model.

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Esta ponencia describe una metodología para la evaluación de los servicios de telecomunicación desde la perspectiva de los usuarios. La metodología se basa en una clasificación de los servicios y sus componentes que es comprensible para los usuarios y en la identificación de los distintos factores de la calidad de servicio que afectan y determinan la calidad de servicio percibida por los usuarios. Basándose en estas clasificaciones, se estudian los componentes y relaciones de un sistema que permita evaluar la QoS de las ofertas de servicios de distintos proveedores. Dicha evaluación se basa en un modelo que establece la correspondencia entre la calidad percibida por el usuario y las funciones y responsabilidades de los agentes que intervienen en la prestación de un servicio. Por último, se presentan algunos de los resultados obtenidos a partir de la aplicación de la metodología y la línea de trabajos futuros.

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This document describes several design proposals to enhance network sensor performance on multiprocessor architectures. Our main contributions are related to the design of an autonomous sensor and to the idea of performing some parallelization of the analysis. These proposals can be implemented in network sensors such as intrusion detection systems, network antivirus appliances, QoS monitors and any other device based on network traffic analysing. Taking a certain model of traffic analysis as our starting point, we look deeply into some design proposals to address the difficulties involved in the parallelization. In this work, we propose a series of resources that can help us to solve these difficulties. Later, we study the prototypes developed in order to test different design alternatives and, finally, present selected case studies. We finish by quantitatively analysing the results to validate our design proposals.

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This paper offers an approach to the definition of access speed measurements. An ever growing increase of Internet Service Providers (ISP) and different types of technologies in the Internet access, makes it difficult for users to decide which is the best or most suitable connection to satisfy their needs. From these considerations, the possibility of the Internet users to obtain a real and neutral measurement of the service of their Internet access may help them to decide if it is covering their demands or, on the contrary, the provider is not complying with the terms of the contract. In order to perform this measurement, an Internet speed test through web interface has been defined, as well as the way to obtain a measure which can comply with the objective of giving users a proper idea of how their Internet access is working. This project is included in the Quality of Service (QoS) investigation area in our investigation group.

ABSTRACT
The communication is very important in our society. As the need of controling the information interchange increases, data capture system has been implemented. Analysing data can provide essential information like intrusion detection, quality of service statistics, accounting… These scopes are differents so a unified language facilitates to compose rules and to interchange them with other systems. XML (Extensible Markup Language) tags are defined to create a large number of differents and complex rules. Then it was developed a parser which load in memory these rules.

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During the last years the use of computers and Telematic networks has permited to surpass the barriers of space and time to facilitate interactive and personalised contact among the members of University community. The concept of a Virtual Campus has been introduced, offering several advantages over the traditional education: for instance, an easier communication between teachers and students and a solution for time and space problems. In this context the development of the system described in this document is aimed at helping users to smartly schedule projects, activities and tasks for an optimum use of work and effort, in an educational enviroment and in a simple and flexible way.

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During the 90's the exponential growth of the number of Internet users led to the birth of many ISPs and data operators. Nowadays, after the technological bubble, only some of them survive. Since prices have reached the lowest limit, some kind of service quality differentiation between competitors is a must. Unfortunately, QoS measuring methods don’t always agree with users' expectations. Moreover, many times data operators don't know how to improve the quality that users perceive. Any investment on infrastructures seems to result on an improvement, but there are no guarantees. This article describes the effort of a group of Spanish Universities towards the definition of a method to set up and measure the relationships between users' satisfaction and network parameters. The model developed would allow both ISPs and legislators to control the degree of users' satisfaction, as well as how any change in network parameters results on a variation of their perceptions.

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This paper presents an analytical model based in queueing theory which allows to represent the behavior of an intrusion detection system . Besides, an iterative calculation method based in the mean value method has been developed to obtain the most significant parameters of the system, for example throughput. In the future, the main objective of this work is to extend the analytical model of this intrusion detection system to any generic multiprocessor architecture.