480 research outputs found

    Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

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    Reliable Multicast Transport for Heterogeneous Mobile IP environment using Cross-Layer Information

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    Reliable multicast transport architecture designed for heterogeneous mobile IP environment using cross-layer information for enhanced Quality of Service (QoS) and seamless handover is discussed. In particular, application-specific reliable multicast retransmission schemes are proposed, which are aimed to minimize the protocol overhead taking into account behaviour of mobile receivers (loss of connectivity and handover) and the specific application requirements for reliable delivery (such as carousel, one-to-many download and streaming delivery combined with recording). The proposed localized retransmission strategies are flexible configured for tree-based multicast transport. Cross layer interactions in order to enhance reliable transport and support seamless handover is discussed considering IEEE 802.21 media independent handover mechanisms. The implementation is based on Linux IPv6 environment. Simulations in ns2 focusing on the benefits of the proposed multicast retransmission schemes for particular application scenarios are presented

    WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches

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    WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations

    On providing mobility management in WOBANs: Integration with PMIPv6 and MIH

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    The Wireless-Optical Broadband Access Network (WOBAN) is a promising access architecture that combines the high performance of optical networks with the ubiquity and convenience of wireless technologies. This article proposes a network-based mobility framework that is specially tailored for WOBANs. The proposed architecture is based on Proxy Mobile IPv6 and IEEE 802.21 mobility management protocols, but it also defines a number of optimizations that enable the seamless handover of mobile nodes. In particular, the hierarchical architecture together with the broadcast-and-select nature of the optical part of the WOBAN are leveraged to: optimize the mobility of users with respect to the overall network resources, both at the wireless access and optical distribution parts, remove the overhead of IP-in-IP tunneling between the PMIPv6 entities, and perform an efficient bicasting during the handover process to minimize packet loss.The authors would like to acknowledge the support of the EU-funded MEDIEVAL (grant FP7-ICT-2009-5/258053), the CAM-funded Medianet project (under code S-2009/TIC-1468) and the MICINN research grant TIN2010-20136-C03.European Community's Seventh Framework ProgramPublicad

    SoluçÔes de broadcast para redes 4G

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    Mestrado em Engenharia ElectrĂłnica e de TelecomunicaçÔesA primeira difusĂŁo de conteĂșdos video e audio teve um forte impacto no quotidiano da população que assistiu a uma revolução nos modelos de transmissĂŁo de informação e de entretenimento. A evolução desde entĂŁo foi significativa, e jĂĄ na era digital, encontramo-nos face a uma nova sub-elevação da metodologia e do conceito subjacentes Ă  transmissĂŁo de conteudos multimĂ©dia. O mundo actual apresenta, contudo, diferentes requisitos, de entre os quais se destacam a procura pela alta definição e mobilidade. A mobilidade tem sido um particular foco de atenção por parte dos operadores que exploram agora modelos para entregar uma vasta gama de serviços que sejam atractivos para os utilizadores. Esta dissertação apresenta um sumĂĄrio das tecnologias emergentes de broadcast que se distinguem nas vĂĄrias partes do mundo com a sua particular incidĂȘncia geogrĂĄfica, caracterĂ­sticas e cenĂĄrios de aplicação. É ainda apresentada uma arquitectura 4G abordando assuntos inerentes Ă  mobilidade e qualidade de serviço com particular incidĂȘncia nos aspectos relacionados com a integração de uma tecnologia de broadcast particular. Para avaliação da arquitectura proposta foram efectuados estudos com base num equipamento de broadcast na sua versĂŁo comercial, permitindo desta forma obter uma anĂĄlise que ilustra o que os operadores podem esperar do estado actual dos dispositivos. Os resultados permitiram retirar ilaçÔes sobre o comportamento de um equipamento considerado como um produto final a disponibilizar aos operadores, quando integrado num ambiente 4G com suporte de mobilidade e QoS. Nomeadamente Ă© discutida a sua aplicabildiade tendo em linha de conta as desvantagens introduzidas pelas caracterĂ­sticas inerentes Ă  prĂłpria tecnologia.Broadcast of video and audio through analogical television completely changed the paradigm of information and entertainment divulgation. Today, in the “digital era”, the Analogue Switch Off revolution is being held. Manufacturers and operators already show concerns regarding the support of mobility, quality of experience and of service. Delivering competitive High Definition contents and providing solutions for the average “on-the-move” user are two of the most important issues to be dealt by the service providers, which are also within the analysis scope of this work. This dissertation presents an overview on the most relevant broadcast technologies which are assumed to be of relative acceptance in their respective target market. It presents their main characteristics and applicability. 4G architectural concepts are also analyzed, closely dealing with mobility and quality of service provisioning, with particular focus on the seamless integration of broadcast technologies. As a mean to evaluate the feasibility of integrating broadcast technologies with 4G architectures, a performance evaluation study was performed using commercial equipment. In this way a several set of considerations constructed illustrating the features and functionalities which operators can expect or disregard from professional commercial broadcasting devices. Results allow the withdrawing of conclusions concerning the integration of a final broadcasting solution when incorporated within a 4G environment with QoS and mobility support. Its applicability is evaluated having in mind the performance drawbacks introduced by the specific technology, and generalized towards the gathering of more general conclusions which consider the main characteristics of the commercial broadcasting devices

    Security-centric analysis and performance investigation of IEEE 802.16 WiMAX

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