111 research outputs found
Future Trends and Challenges for Mobile and Convergent Networks
Some traffic characteristics like real-time, location-based, and
community-inspired, as well as the exponential increase on the data traffic in
mobile networks, are challenging the academia and standardization communities
to manage these networks in completely novel and intelligent ways, otherwise,
current network infrastructures can not offer a connection service with an
acceptable quality for both emergent traffic demand and application requisites.
In this way, a very relevant research problem that needs to be addressed is how
a heterogeneous wireless access infrastructure should be controlled to offer a
network access with a proper level of quality for diverse flows ending at
multi-mode devices in mobile scenarios. The current chapter reviews recent
research and standardization work developed under the most used wireless access
technologies and mobile access proposals. It comprehensively outlines the
impact on the deployment of those technologies in future networking
environments, not only on the network performance but also in how the most
important requirements of several relevant players, such as, content providers,
network operators, and users/terminals can be addressed. Finally, the chapter
concludes referring the most notable aspects in how the environment of future
networks are expected to evolve like technology convergence, service
convergence, terminal convergence, market convergence, environmental awareness,
energy-efficiency, self-organized and intelligent infrastructure, as well as
the most important functional requisites to be addressed through that
infrastructure such as flow mobility, data offloading, load balancing and
vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and
Services, Nova Science Publishers, 201
Recommended from our members
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
A Cross-System Approach for Multimedia Services with IP Multicast in 4G Networks
The increased demand for multimedia services by mobile end users in recent years have driven both Broadcast and Wireless Network operators to develop new systems and architectures for the deployment of such services. The proposed solutions are nonetheless limited either in terms of QoS or Capabilities to deliver new interactive services. This paper highlights strengths and drawbacks of the existing technologies in terms of QoS, Security and Mobility. In order to fill the gap between current solutions we propose a new architecture that builds itself on the synergies created by a heterogeneous network made of existing delivering technologies, such as 3GPP/MBMS and DVB, where services can be delivered to end-users in the most appropriate way for end-users and operators alike. A prototype implementation is further described.EU project - IST-2002- 506997 Daidalos I
Distribuição de vĂdeo para grupos de utilizadores em redes mĂłveis heterogĂ©neas19
The evolutions veri ed in mobile devices capabilities (storage capacity, screen
resolution, processor, etc.) over the last years led to a signi cant change
in mobile user behavior, with the consumption and creation of multimedia
content becoming more common, in particular video tra c. Consequently,
mobile operator networks, despite being the target of architectural evolutions
and improvements over several parameters (such as capacity, transmission
and reception performance, amongst others), also increasingly become more
frequently challenged by performance aspects associated to the nature of
video tra c, whether by the demanding requirements associated to that
service, or by its volume increase in such networks.
This Thesis proposes modi cations to the mobile architecture towards a more
e cient video broadcasting, de ning and developing mechanisms applicable
to the network, or to the mobile terminal. Particularly, heterogeneous
networks multicast IP mobility supported scenarios are focused, emphasizing
their application over di erent access technologies. The suggested changes
are applicable to mobile or static user scenarios, whether it performs the role
of receiver or source of the video tra c. Similarly, the de ned mechanisms
propose solutions targeting operators with di erent video broadcasting goals,
or whose networks have di erent characteristics. The pursued methodology
combined an experimental evaluation executed over physical testbeds,
with the mathematical evaluation using network simulation, allowing the
veri cation of its impact on the optimization of video reception in mobile
terminalsA evolução veri cada nas caracterĂsticas dos dispositivos moveis (capacidade
de armazenamento, resolução do ecrã, processador, etc.) durante os
Ășltimos anos levou a uma alteração signi cativa nos comportamentos dos
utilizadores, sendo agora comum o consumo e produção de conteĂșdos
multimĂ©dia envolvendo terminais mĂłveis, em particular o trĂĄfego vĂdeo.
Consequentemente, as redes de operador móvel, embora tendo também sido
alvo constante de evoluçÔes arquitecturais e melhorias em vårios parùmetros
(tais como capacidade, ritmo de transmissĂŁo/recepção, entre outros), vĂȘemse
cada vez mais frequentemente desa adas por aspectos de desempenho
associados Ă natureza do trĂĄfego de vĂdeo, seja pela exigĂȘncia de requisitos
associados a esse serviço, quer pelo aumento do volume do mesmo nesse
tipo de redes.
Esta Tese propĂŽe alteraçÔes Ă arquitetura mĂłvel para a disseminação de vĂdeo
mais e ciente, de nindo e desenvolvendo mecanismos aplicĂĄveis Ă rede, ou
ao utilizador mĂłvel. Em particular, sĂŁo focados cenĂĄrios suportados por IP
multicast em redes mĂłveis heterogĂ©neas, isto Ă©, com ĂȘnfase na aplicação
destes mecanismos sobre diferentes tecnologias de acesso. As alteraçÔes
sugeridas aplicam-se a cenĂĄrios de utilizador estĂĄtico ou mĂłvel, sendo este a
fonte ou receptor do trĂĄfego vĂdeo. Da mesma forma, sĂŁo propostas soluçÔes
tendo em vista operadores com diferentes objectivos de disseminação de
vĂdeo, ou cujas redes tĂȘm diferentes caracterĂsticas. A metodologia utilizada
combinou a avaliação experimental em testbeds fĂsicas com a avaliação
matemåtica em simulaçÔes de redes, e permitiu veri car o impacto sobre
a optimização da recepção de vĂdeo em terminais mĂłveisPrograma Doutoral em TelecomunicaçÔe
Mobility management across converged IP-based heterogeneous access networks
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 8/2/2010.In order to satisfy customer demand for a high performance âglobalâ mobility service, network operators (ISPs, carriers, mobile operators, etc.) are facing the need to evolve to a converged âall-IPâ centric heterogeneous access infrastructure. However, the integration of such heterogeneous access networks (e.g. 802.11, 802.16e, UMTS etc) brings major mobility issues. This thesis tackles issues plaguing existing mobility management solutions in converged IP-based heterogeneous networks. In order to do so, the thesis firstly proposes a cross-layer mechanism using the upcoming IEEE802.21 MIH services to make intelligent and optimized handovers. In this respect, FMIPv6 is integrated with the IEEE802.21 mechanism to provide seamless mobility during the overall handover process. The proposed solution is then applied in a simulated vehicular environment to optimize the NEMO handover process. It is shown through analysis and simulations of the signalling process that the overall expected handover (both L2 and L3) latency in FMIPv6 can be reduced by the proposed mechanism by 69%. Secondly, it is expected that the operator of a Next Generation Network will provide mobility as a service that will generate significant revenues. As a result, dynamic service bootstrapping and authorization mechanisms must be in place to efficiently deploy a mobility service (without static provisioning), which will allow only legitimate users to access the service. A GNU Linux based test-bed has been implemented to demonstrate this. The experiments presented show the handover performance of the secured FMIPv6 over the implemented test-bed compared to plain FMIPv6 and MIPv6 by providing quantitative measurements and results on the quality of experience perceived by the users of IPv6 multimedia applications. The results show the inclusion of the additional signalling of the proposed architecture for the purpose of authorization and bootstrapping (i.e. key distribution using HOKEY) has no adverse effect on the overall handover process. Also, using a formal security analysis tool, it is shown that the proposed mechanism is safe/secure from the induced security threats. Lastly, a novel IEEE802.21 assisted EAP based re-authentication scheme over a service authorization and bootstrapping framework is presented. AAA based authentication mechanisms like EAP incur signalling overheads due to large RTTs. As a result, overall handover latency also increases. Therefore, a fast re-authentication scheme is presented which utilizes IEEE802.21 MIH services to minimize the EAP authentication process delays and as a result reduce the overall handover latency. Analysis of the signalling process based on analytical results shows that the overall handover latency for mobility protocols will be approximately reduced by 70% by the proposed scheme
Media independent handovers : network selection for mobile IP nodes in heterogeneous wireless networks
Includes abstract.Includes bibliographical references (p. 79-82).In Next Generation Networks (NGN), also known as 4G, Beyond 3G, Converged, Integrated and Interworked Network, user node mobility in wireless and wired environments will seamlessly cross disparate network boundaries. The effort to offer ubiquitous computing, providing access to services anywhere and anytime, strongly encourages the ability to roam across the different existing and future networks. Literature shows investigation of concepts such as Always Best Connected (ABC) when heterogeneous networks co-exist , which will work or compete with other schemes like Home Network Default (HND), Compatibility and Network Operator Agreements (CNOA) to guide network selection or access . With the variety of available networks, the mobile node may be faced with having to decide which network to connect to. We concentrate on the network selection aspects of these envisaged mobile, overlay and integrated environment in heterogeneous networks. The standard developments by the IEEE802.21 Working group and the IETF Networking group form the base of our approach that seeks to see mobility across heterogeneous networks a reality. We propose an IEEE802.21 Media Independent Handover Function (MIHF) based network discovery and network selection, leading to a handover. The selection may be further assisted by an MIHF capable Broker Node that is Third party to the Network Providers to provide a central yet distributed database of the available networks as encountered by the Mobile Node, to cater for Nodes with no prior knowledge of networks and software repository. A Mobile Node (MN) in our solution uses 802.21 communication messages to obtain information about foreign networks encountered before selecting the networks to connect to. Our evaluation through simulations, shows that network selection in heterogeneous wireless networks environment for the appropriately equipped devices is greatly enhanced by the use of the Media Independent Handover Protocol. In scenarios where the mobile node has no prior knowledge of the encountered different network architectures, the use of a Broker node can, for an optimal number of available networks also greatly enhance the mobile nodeâs network selection by reducing the delay associated and the packet losses incurred
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