480 research outputs found
Reliable Multicast Transport for Heterogeneous Mobile IP environment using Cross-Layer Information
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
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 userâs 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
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
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Design of interface selection protocols for multi-homed wireless networks
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 10 December 2010.The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of âunreachable zonesâ, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios
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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
SoluçÔes de broadcast para redes 4G
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. Ă 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 âdigital eraâ, 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 âon-the-moveâ 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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