Informed Network Coding for Minimum Decoding Delay

Network coding is a highly efficient data dissemination mechanism for wireless networks. Since network coded information can only be recovered after delivering a sufficient number of coded packets, the resulting decoding delay can become problematic for delay-sensitive applications such as real-time media streaming. Motivated by this observation, we consider several algorithms that minimize the decoding delay and analyze their performance by means of simulation. The algorithms differ both in the required information about the state of the neighbors' buffers and in the way this knowledge is used to decide which packets to combine through coding operations. Our results show that a greedy algorithm, whose encodings maximize the number of nodes at which a coded packet is immediately decodable significantly outperforms existing network coding protocols.Comment: Proc. of the IEEE International Conference on Mobile Ad-hoc and Sensor Systems (IEEE MASS 2008), Atlanta, USA, September 200

Effective Delay Control in Online Network Coding

Motivated by streaming applications with stringent delay constraints, we consider the design of online network coding algorithms with timely delivery guarantees. Assuming that the sender is providing the same data to multiple receivers over independent packet erasure channels, we focus on the case of perfect feedback and heterogeneous erasure probabilities. Based on a general analytical framework for evaluating the decoding delay, we show that existing ARQ schemes fail to ensure that receivers with weak channels are able to recover from packet losses within reasonable time. To overcome this problem, we re-define the encoding rules in order to break the chains of linear combinations that cannot be decoded after one of the packets is lost. Our results show that sending uncoded packets at key times ensures that all the receivers are able to meet specific delay requirements with very high probability.Comment: 9 pages, IEEE Infocom 200

Video transport optimization techniques design and evaluation for next generation cellular networks

Video is foreseen to be the dominant type of data traffic in the Internet. This vision is supported by a number of studies which forecast that video traffic will drastically increase in the following years, surpassing Peer-to-Peer traffic in volume already in the current year. Current infrastructures are not prepared to deal with this traffic increase. The current Internet, and in particular the mobile Internet, was not designed with video requirements in mind and, as a consequence, its architecture is very inefficient for handling this volume of video traffic. When a large part of traffic is associated to multimedia entertainment, most of the mobile infrastructure is used in a very inefficient way to provide such a simple service, thereby saturating the whole cellular network, and leading to perceived quality levels that are not adequate to support widespread end user acceptance. The main goal of the research activity in this thesis is to evolve the mobile Internet architecture for efficient video traffic support. As video is expected to represent the majority of the traffic, the future architecture should efficiently support the requirements of this data type, and specific enhancements for video should be introduced at all layers of the protocol stack where needed. These enhancements need to cater for improved quality of experience, improved reliability in a mobile world (anywhere, anytime), lower exploitation cost, and increased flexibility. In this thesis a set of video delivery mechanisms are designed to optimize the video transmission at different layers of the protocol stack and at different levels of the cellular network. Upon the architectural choices, resource allocation schemes are implemented to support a range of video applications, which cover video broadcast/multicast streaming, video on demand, real-time streaming, video progressive download and video upstreaming. By means of simulation, the benefits of the designed mechanisms in terms of perceived video quality and network resource saving are shown and compared to existing solutions. Furthermore, selected modules are implemented in a real testbed and some experimental results are provided to support the development of such transport mechanisms in practice

A cloud-enabled small cell architecture in 5G networks for broadcast/multicast services

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The evolution of 5G suggests that communication networks become sufficiently flexible to handle a wide variety of network services from various domains. The virtualization of small cells as envisaged by 5G, allows enhanced mobile edge computing capabilities, thus enabling network service deployment and management near the end user. This paper presents a cloud-enabled small cell architecture for 5G networks developed within the 5G-ESSENCE project. This paper also presents the conformity of the proposed architecture to the evolving 5G radio resource management architecture. Furthermore, it examines the inclusion of an edge enabler to support a variety of virtual network functions in 5G networks. Next, the improvement of specific key performance indicators in a public safety use case is evaluated. Finally, the performance of a 5G enabled evolved multimedia broadcast multicast services service is evaluated.Peer ReviewedPostprint (author's final draft

Video transport optimization techniques design and evaluation for next generation cellular networks

Video is foreseen to be the dominant type of data traffic in the Internet. This vision is supported by a number of studies which forecast that video traffic will drastically increase in the following years, surpassing Peer-to-Peer traffic in volume already in the current year. Current infrastructures are not prepared to deal with this traffic increase. The current Internet, and in particular the mobile Internet, was not designed with video requirements in mind and, as a consequence, its architecture is very inefficient for handling this volume of video traffic. When a large part of traffic is associated to multimedia entertainment, most of the mobile infrastructure is used in a very inefficient way to provide such a simple service, thereby saturating the whole cellular network, and leading to perceived quality levels that are not adequate to support widespread end user acceptance. The main goal of the research activity in this thesis is to evolve the mobile Internet architecture for efficient video traffic support. As video is expected to represent the majority of the traffic, the future architecture should efficiently support the requirements of this data type, and specific enhancements for video should be introduced at all layers of the protocol stack where needed. These enhancements need to cater for improved quality of experience, improved reliability in a mobile world (anywhere, anytime), lower exploitation cost, and increased flexibility. In this thesis a set of video delivery mechanisms are designed to optimize the video transmission at different layers of the protocol stack and at different levels of the cellular network. Upon the architectural choices, resource allocation schemes are implemented to support a range of video applications, which cover video broadcast/multicast streaming, video on demand, real-time streaming, video progressive download and video upstreaming. By means of simulation, the benefits of the designed mechanisms in terms of perceived video quality and network resource saving are shown and compared to existing solutions. Furthermore, selected modules are implemented in a real testbed and some experimental results are provided to support the development of such transport mechanisms in practice.Il traffico video sarà il tipo di applicazione dominante in Internet nei prossimi anni. Già in questi anni assistiamo al sorpasso del traffico video mobile rispetto al Peer-to-Peer. Le infrastrutture attuali non sono preparate ad affrontare questo aumento di traffico video. Internet, e in particolare Internet mobile, non è stata progettata sulla base di requisiti video e, di conseguenza, la sua architettura è inefficiente nel gestire questo tipo di traffico. Quando il traffico è associato all'intrattenimento multimediale, la maggior parte dell'infrastruttura mobile è utilizzata in un modo inefficiente pur fornendo un servizio semplice, saturando in tal modo l'intera rete cellulare e portando il servizio a livelli di qualità non adeguati a sostenere quella che gli utenti si aspettano di ricevere. L'obiettivo principale dell'attività di ricerca in questa tesi è quello di evolvere l'architettura di Internet mobile per un efficiente supporto del traffico video. Poiché il video è previsto rappresentare la maggior parte del traffico, l'architettura di rete deve supportare in modo efficiente le esigenze di questo tipo di traffico e miglioramenti specifici dovrebbero essere introdotti a tutti i livelli dello stack protocollare. Questi miglioramenti hanno lo scopo di incrementare la qualità percepita del servizio, di dare una maggiore affidabilità in un mondo mobile, di abbassare i costi di servizio e di aumentare la flessibilità della rete. In questa tesi una serie di meccanismi di trasmissione video sono progettati per ottimizzare la consegna di applicazioni video su reti cellulari di nuova generazione a diversi livelli dello stack protocollare ed a differenti livelli della rete cellulare. Sulla base di queste scelte architetturali, sistemi di allocazione delle risorse sono implementati per supportare una gamma di applicazioni video che copre il video broadcast/multicast in streaming, video on demand, streaming in tempo reale, il video download progressivo e il video upstreaming. Tramite campagne di simulazioni, i benefici sotto forma di qualità percepita e di risorse di rete risparmiate sono riportati attraverso il confronto con soluzioni pre-esistenti. Inoltre moduli selezionati sono implementati in un vero e proprio banco di prova e alcuni dei risultati sperimentali conseguiti sono usati per sostenere lo sviluppo di nuovi meccanismi di trasporto video nelle reti mobili future

Robust opportunistic broadcast scheduling for scalable video streaming

In this paper we design a robust opportunistic scheduler to be implemented at the base station in a cellular network for broadcast media streaming applications. The scheduling mechanism operates based on information on both the average and the instantaneous user distributions, and on radio link channel quality, obtained through the cellular uplink channel. Video streams are encoded into multiple scalable video layers, that are split into video packets opportunistically scheduled at the base station with the goal of minimizing the wireless resource usage while keeping the overall target Quality of Service (QoS) in the cell. We finally discuss potential extensions of this framework to more sophisticated scheduling solutions for broadcast video delivery over next generation cellular networks

Opportunistic scheduling and rate adaptation for scalable broadcast video streaming

In this work we propose an adaptation framework where video packets are opportunistically scheduled for broadcast/multicast media streaming applications. The scheduling mechanism operates based on the average and instantaneous user distributions and radio link channel quality, information obtained through the cellular uplink channel. In our framework we use H.264 Scalable Video Coding (SVC) to generate multiple independent streams or scalable sub-streams, further split into video packets, which are opportunistically scheduled with the goal of maximizing the average quality of service for the end user. Based on the design of our delivery system, we finally foresee practical implementations of efficient scheduling algorithms for broadcast video delivery over next generation cellular networks

A Fast Rate-Adaptation Algorithm for Robust Wireless Scalable Streaming Applications

In this paper we consider a server sending a scalable video stream over a wireless channel to an end-user. We design a fast rate adaptation algorithm which chooses the right transmission policy (video data and associated unequal error protection) based on channel feedback. Our algorithm can be easily implemented as a smart scheduling module at the server side, which adapts its packet selection rules based on the total available channel rate and losses experienced by the end-user. Our simulation results show the good performance of our algorithm compared to the optimal transmission policy, for a wide range of channel conditions. We also identify scenarios that fully benefit from scalable encoding augmented by unequal error protection, compared to traditional bitstream-switching methods based on single stream transmission protected by FEC