Performance evaluation of AL-FEC LDPC codes for push content applications in wireless unidirectional environments

The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-011-0841-yFEC (Forward Error Correction) mechanisms improve IP content transmission reliability through the recovery of packets lost in transmission. Opposite to ARQ (Automatic Repeat Request), FEC mechanisms are especially suited to unidirectional environments or to multicast environments where multiple receivers perceived different channel losses, thus making difficult the implementation of mechanisms based on feedback information. Among the different types of FEC codes, this paper presents a thorough performance evaluation of LDPC (Low Density Parity Check) codes, based on an implementation developed by the authors, according to the specifications defined by RFC 5170 for the usage of LDPC codes by push content applications based on the FLUTE protocol. LDPC codes provide a good trade-off between performance and complexity, hence, they are appropriate for mobile applications. Contributions of this paper include tests conducted with commercial mobile phones connected to the push content download server over a Wi-Fi network. The evaluation highlights the advantages of using packet level FEC encoding in file transmission over unidirectional networks and provides with a comparison between two kinds of LDPC structures: Staircase and Triangle. This is accomplished by calculating the inefficiency ratio of these LDPC structures in different environments. Results show that the implemented LDPC codes can provide inefficiency ratios close to one when the different coding parameters (as the code rate or the number of blocks) are configured to an optimal value that depends on the packet loss rate. © 2011 Springer Science+Business Media, LLC.This work was supported in part by the Ministry of Industry, Tourism and Trade of the Government of Spain, under project "Redes Hibridas para la Provision de Servicios Turisticos" (TSI-020302-2010-165).De Fez Lava, I.; Fraile Gil, F.; Belda Ortega, R.; Guerri Cebollada, JC. (2012). Performance evaluation of AL-FEC LDPC codes for push content applications in wireless unidirectional environments. Multimedia Tools and Applications. 60(3):669-688. https://doi.org/10.1007/s11042-011-0841-yS6696886033GPP TS 22.146 (2006) Multimedia broadcast/multicast service; stage 1 (release 6), V6.7.03GPP TS 25.346 (2007) Introduction of the Multimedia Broadcast Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2 (Release8), V8.0.0Bai H, Atiquzzaman M (2003) Error modeling schemes for fading channels in wireless communications: a survey. IEEE Comm Surv Tutorials 5(2)Cunche M, Roca V (2008) Optimizing the error recovery capabilities of LDPC-staircase codes featuring a Gaussian elimination decoding scheme. Proc. of the 10th IEEE International Workshop on Signal Processing for Space Communications (SPSC), Rhodes Island, GreeceCunche M, Roca V (2008) Improving the decoding of LDPC codes for the packet erasure channel with a hybrid Zyablov iterative decoding/Gaussian elimination scheme. 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IETF RFC 3926Park S, Miller K (1990) Random number generators: good ones are hard to find. Commun ACM 33(1):87–88INRIA Planète Research Team (2006) LDPC large block FEC codec distribution, http://planete-bcast.inrialpes.fr/article.php3?id_article=16Roca V, Neumann C (2004) Design, evaluation and comparison of four large block FEC codecs, LDPC, LDGM, LDGM staircase and LDGM triangle, plus a Reed-Solomon small block FEC codec. INRIA Research Report RR-5225Roca V, Neumann C, Furodet D (2008) Low Density Parity Check (LDPC) Staircase and Triangle Forward Error Correction (FEC) schemes. IETF RFC 5170Shokrollahi A (2006) Raptor codes. IEEE Transactions on Information Theory no. 6Watson M (2009) Basic Forward Error Correction (FEC) schemes. IETF RFC 5445Watson M, Luby M, Vicisano L (2007) Forward Error Correction (FEC) building block. IETF RFC 5052White Paper (2009) Integrated Mobile Broadcast (IMB): the power of predictive broadcasting for 3G multimedia application

A personalized system for scalable distribution of multimedia content in multicast wireless networks

The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-014-2139-3This paper presents a novel architecture for scalable multimedia content delivery over wireless networks. The architecture takes into account both the user preferences and context in order to provide personalized contents to each user. In this way, third-party applications filter the most appropriate contents for each client in each situation. One of the key characteristics of the proposal is the scalability, which is provided, apart from the use of filtering techniques, through the transmission in multicast networks. In this sense, content delivery is carried out by means of the FLUTE (File Delivery over Unidirectional Transport) protocol, which provides reliability in unidirectional environments through different mechanisms such as AL-FEC (Application Layer Forward Error Correction) codes, used in this paper. Another key characteristic is the context-awareness and personalization of content delivery, which is provided by means of context information, user profiles, and adaptation. The system proposed is validated through several empirical studies. Specifically, the paper presents evaluations of two types that collect objective and subjective measures. The first evaluate the efficiency of the transmission protocol, analyzing how the use of appropriate transmission parameters reduces the download time (and thus increasing the Quality of Experience), which can be minimized by using caching techniques. On the other hand, the subjective measures present a study about the user experience after testing the application and analyze the accuracy of the filtering process/strategy. Results show that using AL-FEC mechanisms produces download times until four times lower than when no protection is used. Also, results prove that there is a code rate that minimizes the download time depending on the losses and that, in general, code rates 0.7 and 0.9 provide good download times for a wide range of losses. On the other hand, subjective measures indicate a high user satisfaction (more than 80 %) and a relevant degree of accuracy of the content adaption.This work is supported in part by the Ministerio de Economia y Competitividad of the Government of Spain under project COMINN (IPT-2012-0883-430000) and by the project PAID/2012/313 from the PAID-05-12 program of the Vicerrectorado de Investigacion of the Universitat Politecnica de Valencia.De Fez Lava, I.; Gil Pascual, M.; Fons Cors, JJ.; Guerri Cebollada, JC.; Pelechano Ferragud, V. (2014). A personalized system for scalable distribution of multimedia content in multicast wireless networks. 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Analysis and evaluation of adaptive LDPC AL-FEC codes for content download services

This paper proposes the use of adaptive low density parity check (LDPC) application layer-forward error correction (AL-FEC) codes for content download services over erasure channels. In adaptive LDPC codes, clients inform the content download server of the losses they are experiencing. Using this information, the server makes forward error correction (FEC) parity symbols available to the client at an optimum code rate. This paper presents an analytical model of the proposed adaptive LDPC codes. The model is validated through measurements realized with an application prototype. In addition, results show the performance of these codes in different scenarios, compared to the performance of nonadaptive AL-FEC, optimum LDPC AL-FEC codes, and an almost ideal rateless code. Adaptive LDPC AL-FEC codes achieve download times similar to almost ideal rateless codes with less coding complexity, at the expense of an interaction channel between server and clients.De Fez Lava, I.; Fraile Gil, F.; Belda Ortega, R.; Guerri Cebollada, JC. (2012). Analysis and evaluation of adaptive LDPC AL-FEC codes for content download services. IEEE Transactions on Multimedia. 60(3):641-650. doi:10.1109/TMM.2012.2190392S64165060

RS + LDPC-Staircase Codes for the Erasure Channel: Standards, Usage and Performance

Application-Level Forward Erasure Correction (AL-FEC) codes are a key element of telecommunication systems. They are used to recover from packet losses when retransmission are not feasible and to optimize the large scale distribution of contents. In this paper we introduce Reed-Solomon/LDPCStaircase codes, two complementary AL-FEC codes that have recently been recognized as superior to Raptor codes in the context of the 3GPP-eMBMS call for technology [1]. After a brief introduction to the codes, we explain how to design high performance codecs which is a key aspect when targeting embedded systems with limited CPU/battery capacity. Finally we present the performances of these codes in terms of erasure correction capabilities and encoding/decoding speed, taking advantage of the 3GPP-eMBMS results where they have been ranked first

Evaluation of background push content download services to mobile devices over DVB networks

© 2014 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.This paper proposes a multicast content download service based on the use of residual network capacity to push multimedia content to available local storage in personal multimedia devices. The service under study is based on the FLUTE protocol. Specifically, FLUTE packets fill the spare capacity in the IP tunnels reserved for the primary streaming service (opportunistic insertion). The paper also evaluates the use of AL-FEC parity to overcome transmission errors,object multiplexing to send the most popular multimedia contents more frequently and cache management policies that consider user preferences in order to keep in storage the most useful items. The service has been evaluated through simulations and measurements performed with an application prototype based on the DVB-H standards. The results show that AL-FEC enables the use of residual capacity for background content download services. In turn, AL-FEC, as well as object multiplexing, improves the relation between the number of content items and the overall access time. Moreover, results show that high percentages of requests can be served from the local cache of the service, provided that it is possible to estimate the popularity of content items and the user preferences.This work was supported by the PAID-05-12 program of the UniversitatPolitecnica de Valencia.Fraile Gil, F.; De Fez Lava, I.; Guerri Cebollada, JC. (2014). Evaluation of background push content download services to mobile devices over DVB networks. IEEE Transactions on Broadcasting. 60(1):1-15. https://doi.org/10.1109/TBC.2013.2289639S11560

An Adaptive Mechanism for Optimal Content Download in Wireless Networks

This paper presents an adaptive mechanism for improving the content download in wireless environments. The solution is based on the use of the file delivery over unidirectional transport (FLUTE) protocol in multicast networks, which reduce considerably the bandwidth when there are many users interested in the same contents. Specifically, the system proposed reduces the average download time of clients within the coverage area, thus improving the Quality of Experience. To that extent, clients send periodically feedback messages to the server reporting the losses they are experiencing. With this information, the server decides which is the optimum application layer forward error correction (AL-FEC) code rate that minimizes the average download time, taking into account the channel bandwidth, and starts sending data with that code rate. The system proposed is evaluated in various scenarios, considering different distributions of losses in the coverage area. Results show that the adaptive solution proposed is very suitable in wireless networks with limited bandwidth.This work is supported in part by the Ministerio de Economia y Competitividad of the Government of Spain under project COMINN (IPT-2012-0883-430000). The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Wenwu Zhu.De Fez Lava, I.; Guerri Cebollada, JC. (2014). An Adaptive Mechanism for Optimal Content Download in Wireless Networks. IEEE Transactions on Multimedia. 16(4):1140-1155. https://doi.org/10.1109/TMM.2014.2307155S1140115516

Large Scale Content Distribution Protocols

This paper introduces large scale content distribution pro- tocols, which are capable of scaling to massive numbers of users and providing low delay end-to-end delivery. Delivery of files and static objects is described, with real-time con- tent streaming being outside the scope of this paper. The focus is on solutions provided by the IETF Reliable Multi- cast Transport Working Group. More precisely, the paper explains FLUTE, ALC and the associated building blocks. Then it discusses how these components are used in the Multimedia Broadcast Multicast Service (MBMS) for 3G systems and in the IP Datacast (IPDC) service for Digital Video Broadcast for Handheld devices (DVB-H)

Evaluation of unidirectional background push content download services for the delivery of television programs

Este trabajo de tesis presenta los servicios de descarga de contenido en modo push como un mecanismo eficiente para el envío de contenido de televisión pre-producido sobre redes de difusión. Hoy en día, los operadores de red dedican una cantidad considerable de recursos de red a la entrega en vivo de contenido televisivo, tanto sobre redes de difusión como sobre conexiones unidireccionales. Esta oferta de servicios responde únicamente a requisitos comerciales: disponer de los contenidos televisivos en cualquier momento y lugar. Sin embargo, desde un punto de vista estrictamente académico, el envío en vivo es únicamente un requerimiento para el contenido en vivo, no para contenidos que ya han sido producidos con anterioridad a su emisión. Más aún, la difusión es solo eficiente cuando el contenido es suficientemente popular. Los servicios bajo estudio en esta tesis utilizan capacidad residual en redes de difusión para enviar contenido pre-producido para que se almacene en los equipos de usuario. La propuesta se justifica únicamente por su eficiencia. Por un lado, genera valor de recursos de red que no se aprovecharían de otra manera. Por otro lado, realiza la entrega de contenidos pre-producidos y populares de la manera más eficiente: sobre servicios de descarga de contenidos en difusión. Los resultados incluyen modelos para la popularidad y la duración de contenidos, valiosos para cualquier trabajo de investigación basados en la entrega de contenidos televisivos. Además, la tesis evalúa la capacidad residual disponible en redes de difusión, por medio de estudios empíricos. Después, estos resultados son utilizados en simulaciones que evalúan las prestaciones de los servicios propuestos en escenarios diferentes y para aplicaciones diferentes. La evaluación demuestra que este tipo de servicios son un recurso muy útil para la entrega de contenido televisivo.This thesis dissertation presents background push Content Download Services as an efficient mechanism to deliver pre-produced television content through existing broadcast networks. Nowadays, network operators dedicate a considerable amount of network resources to live streaming live, through both broadcast and unicast connections. This service offering responds solely to commercial requirements: Content must be available anytime and anywhere. However, from a strictly academic point of view, live streaming is only a requirement for live content and not for pre-produced content. Moreover, broadcasting is only efficient when the content is sufficiently popular. The services under study in this thesis use residual capacity in broadcast networks to push popular, pre-produced content to storage capacity in customer premises equipment. The proposal responds only to efficiency requirements. On one hand, it creates value from network resources otherwise unused. On the other hand, it delivers popular pre-produced content in the most efficient way: through broadcast download services. The results include models for the popularity and the duration of television content, valuable for any research work dealing with file-based delivery of television content. Later, the thesis evaluates the residual capacity available in broadcast networks through empirical studies. These results are used in simulations to evaluate the performance of background push content download services in different scenarios and for different applications. The evaluation proves that this kind of services can become a great asset for the delivery of television contentFraile Gil, F. (2013). Evaluation of unidirectional background push content download services for the delivery of television programs [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31656TESI

Management of Digital Video Broadcasting Services in Open Delivery Platforms

The future of Digital Video Broadcasting (DVB) is moving towards solutions offering an efficient way of carrying interactive IP multimedia services over digital terrestrial broadcasting networks to handheld terminals. One of the most promising technologies is Digital Video Broadcasting-Handheld (DVB-H), at present under standardisation. Services deployed via this type of DVB technologies should enjoy reliability comparable to TV services and high quality standards. However, the market at present does not provide effective and economical solutions for the deployment of such services over multi-domain IP networks, due to their high level of unreliability. This paper focuses on service management, service level agreement (SLA) and network performance requirements of DVB-H services. Experimental results are presented concerning QoS sensitivity to network performance of DVB-H services delivered over a multi-domain IP network. Moreover, a solution for efficient and cost effective service management via QoS monitoring and control and network SLA design is proposed. The solution gives DVB-H operators the possibility of fully managing service QoS without being tied to third party operators