QoE (Quality of Experience) research area
A major driving viewpoint in the development of the Next Generation Networks, concerns the importance of the user/customer needs in the provisioning of the requested service. Indeed, according to this view is the customer subscription and the customer requested service that dictate the running of the network, that is, upon receiving a customer request for a service, the network will assign the service quality and service priority according to the customer subscription and the requested service, and the service priority is used for traffic engineering in case of network congestion. Under such a customer-centric approach, the management plays a role as important as the technology. It is a revolutionary step to transfer from technology-centred approach to a customer-centred approach. According to this vision, the quality of service (and experience) introduces key issues in the design, deployment, provisioning and maintenance of future (and current) NGN architectures and services. The MCLab investigates these issues in the following areas: design of distributed multimedia services, bandwidth management, design of flexible/open/interoperable transport architectures. The followings are some of the main activities carried out in this framework:
Adaptive Techniques for Media Streaming The deployment of services that rely on the streaming of video, audio and voice represents a great challenge for the service provider, especially when the underlying network is not able to guarantee the required level quality of service in terms of delay, jitter and loss constraints. One of this service is that of IP Telephony over mobile ad hoc networks (MANETs), which represent a good platform for the fast deployment of VoIP mobile networks. Within this context, we are studying a new strategy where the optimal routing and de-jittering strategies are jointly addressed at the sender exploing some features of the QOLSR routing algorithm and the ITU-T E-Model for voice quality evaluation. Another multimedia application scenario we are facing is related to the streaming of video content (for TV broadcast and Video on Demand services) over peer-to-peer networks, which are becoming more and more popular thanks to their scalability feature. Within this context, we study the scenario P2P-based VoD services and propose various models of the peer behaviour to evaluate the impact of the peer churn on the system performance.
Transport Control and Management Stratum in NGN: a SOA-oriented Design The objectives of this study are the analysis of the transport management and control functional layer as required in the foreseen (ITU-T) NGN functional architecture, the decomposition of this layer into a set of micro-functionalities according to the SOA paradigm and the implementation of the relevant services to analyze the advantages of the proposed approach. With the intention to follow the evolutionary approach towards the transition into the NGN networks from the current Internet, this study is conducted by taking into account the efforts that have been already devoted in the last decade towards the definition of the technologies and protocols to build multiservice, QoS-aware and TE-oriented networks solutions.
Network Administration using Web Services This activity is aimed at investigating the design of a network management solution that relies on the SOA concepts to access low level network services. The intent is to reduce the gap between the application and the network management, by defining an unique view on the management of the technological assets of an enterprise. In the proposed architecture, the single devices as well as groups of devices are accessed using a web service proxy, which is responsible for dispatching the commands to the devices. To expose those functionalities, the proxy makes use of an object oriented library that hides the inner details of the communications with the physical devices. The resulting solution is made of four levels, which have been defined to simplify the typical management procedures and the implementation of the architecture. An architectural prototype has been developed to evaluate the main advantages, which are: the use of a common formalism for the definition of low level telecommunication services; the use of common interfaces that don’t require the operators to know the inner details of each single service; telco services at the higher levels can be obtained as a composition of other services in the lower layers using a composition and coordination logic.
Subjective Video Quality Assessment The objective of this study is to assess the subjective characteristics of video quality. It is concerned with how video is perceived by a viewer and designates his opinion on a particular video sequence, typically corrupted by one or more coding and/or transmission distortions. We are conducting studies aimed at assessing the Quality of Experience in video streaming when the user is using mobile devices (i.e. tablets). From this study we are creating a database containing subjective assessment scores relative to hundreds of streaming sessions of video sequences encoded with H.264/AVC and affected by distorsions (e.g., playout delay, transmission errors, buffer overflows). Subjective evaluations are conducted in compliance with the ITU-T Recommendation P.910 through single-stimulus Absolute Category Rating (ACR).