188 research outputs found

    Multi-Service Group Key Management for High Speed Wireless Mobile Multicast Networks

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    YesRecently there is a high demand from the Internet Service Providers to transmit multimedia services over high speed wireless networks. These networks are characterized by high mobility receivers which perform frequent handoffs across homogenous and heterogeneous access networks while maintaining seamless connectivity to the multimedia services. In order to ensure secure delivery of multimedia services to legitimate group members, the conventional cluster based group key management (GKM) schemes for securing group communication over wireless mobile multicast networks have been proposed. However, they lack efficiency in rekeying the group key in the presence of high mobility users which concurrently subscribe to multiple multicast services that co-exist in the same network. This paper proposes an efficient multi-service group key management scheme (SMGKM) suitable for high mobility users which perform frequent handoffs while participating seamlessly in multiple multicast services. The users are expected to drop subscriptions after multiple cluster visits hence inducing huge key management overhead due to rekeying the previously visited cluster keys. The already proposed multi-service SMGKM system with completely decentralised authentication and key management functions is adopted to meet the demands for high mobility environment with the same level of security. Through comparisons with existing GKM schemes and simulations, SMGKM shows resource economy in terms of reduced communication and less storage overheads in a high speed environment with multiple visits

    Host mobility management with identifier-locator split protocols in hierarchical and flat networks

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    Includes abstractIncludes bibliographical references.As the Internet increasingly becomes more mobile focused and overloaded with mobile hosts, mobile users are bound to roam freely and attach to a variety of networks. These different networks converge over an IP-based core to enable ubiquitous network access, anytime and anywhere, to support the provision of services, that is, any service, to mobile users. Therefore, in this thesis, the researcher proposed network-based mobility solutions at different layers to securely support seamless handovers between heterogeneous networks in hierarchical and flat network architectures

    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

    Mobile IP movement detection optimisations in 802.11 wireless LANs

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    The IEEE 802.11 standard was developed to support the establishment of highly flexible wireless local area networks (wireless LANs). However, when an 802.11 mobile node moves from a wireless LAN on one IP network to a wireless LAN on a different network, an IP layer handoff occurs. During the handoff, the mobile node's IP settings must be updated in order to re-establish its IP connectivity at the new point of attachment. The Mobile IP protocol allows a mobile node to perform an IP handoff without breaking its active upper-layer sessions. Unfortunately, these handoffs introduce large latencies into a mobile node's traffic, during which packets are lost. As a result, the mobile node's upper-layer sessions and applications suffer significant disruptions due to this handoff latency. One of the main components of a Mobile IP handoff is the movement detection process, whereby a mobile node senses that it is attached to a new IP network. This procedure contributes significantly to the total Mobile IP handover latency and resulting disruption. This study investigates different mechanisms that aim to lower movement detection delays and thereby improve Mobile IP performance. These mechanisms are considered specifically within the context of 802.11 wireless LANs. In general, a mobile node detects attachment to a new network when a periodic IP level broadcast (advertisement) is received from that network. It will be shown that the elimination of this dependence on periodic advertisements, and the reliance instead on external information from the 802.11 link layer, results in both faster and more efficient movement detection. Furthermore, a hybrid system is proposed that incorporates several techniques to ensure that movement detection performs reliably within a variety of different network configurations. An evaluation framework is designed and implemented that supports the assessment of a wide range of movement detection mechanisms. This test bed allows Mobile IP handoffs to be analysed in detail, with specific focus on the movement detection process. The performance of several movement detection optimisations is compared using handoff latency and packet loss as metrics. The evaluation framework also supports real-time Voice over IP (VoIP) traffic. This is used to ascertain the effects that different movement detection techniques have on the output voice quality. These evaluations not only provide a quantitative performance analysis of these movement detection mechanisms, but also a qualitative assessment based on a VoIP application

    Control-data separation architecture for cellular radio access networks: a survey and outlook

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    Conventional cellular systems are designed to ensure ubiquitous coverage with an always present wireless channel irrespective of the spatial and temporal demand of service. This approach raises several problems due to the tight coupling between network and data access points, as well as the paradigm shift towards data-oriented services, heterogeneous deployments and network densification. A logical separation between control and data planes is seen as a promising solution that could overcome these issues, by providing data services under the umbrella of a coverage layer. This article presents a holistic survey of existing literature on the control-data separation architecture (CDSA) for cellular radio access networks. As a starting point, we discuss the fundamentals, concepts, and general structure of the CDSA. Then, we point out limitations of the conventional architecture in futuristic deployment scenarios. In addition, we present and critically discuss the work that has been done to investigate potential benefits of the CDSA, as well as its technical challenges and enabling technologies. Finally, an overview of standardisation proposals related to this research vision is provided

    Traffic and mobility management in large-scale networks of small cells

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    The growth in user demand for higher mobile data rates is driving Mobile Network Operators (MNOs) and network infrastructure vendors towards the adoption of innovative solutions in areas that span from physical layer techniques (e.g., carrier aggregation, massive MIMO, etc.) to the Radio Access Network and the Evolved Packet Core, amongst other. In terms of network capacity, out of a millionfold increase since 1957, the use of wider spectrum (25x increase), the division of spectrum into smaller resources (5x), and the introduction of advanced modulation and coding schemes (5x) have played a less significant role than the improvements in system capacity due to cell size reduction (1600x). This justifies the academic and industrial interest in short-range, low-power cellular base stations, such as small cells. The shift from traditional macrocell-based deployments towards heterogeneous cellular networks raises the need for new architectural and procedural frameworks capable of providing a seamless integration of massive deployments of small cells into the existing cellular network infrastructure. This is particularly challenging for large-scale, all-wireless networks of small cells (NoS), where connectivity amongst base stations is provided via a wireless multi-hop backhaul. Networks of small cells are a cost-effective solution for improving network coverage and capacity in high user-density scenarios, such as transportation hubs, sports venues, convention centres, dense urban areas, shopping malls, corporate premises, university campuses, theme parks, etc. This Ph.D. Thesis provides an answer to the following research question: What is the architectural and procedural framework needed to support efficient traffic and mobility management mechanisms in massive deployments of all-wireless 3GPP Long-Term Evolution networks of small cells? In order to do so, we address three key research challenges in NoS. First, we present a 3GPP network architecture capable of supporting large-scale, all-wireless NoS deployments in the Evolved Packet System. This involves delegating core network functions onto new functional entities in the network of small cells, as well as adapting Transport Network Layer functionalities to the characteristics of a NoS in order to support key cellular services. Secondly, we address the issue of local location management, i.e., determining the approximate location of a mobile terminal in the NoS upon arrival of an incoming connection from the core network. This entails the design, implementation, and evaluation of efficient paging and Tracking Area Update mechanisms that can keep track of mobile terminals in the complex scenario of an all-wireless NoS whilst mitigating the impact on signalling traffic throughout the local NoS domain and towards the core network. Finally, we deal with the issue of traffic management in large-scale networks of small cells. On the one hand, we propose new 3GPP network procedures to support direct unicast communication between LTE terminals camped on the same NoS with minimal involvement from functional entities in the Evolved Packet Core. On the other hand, we define a set of extensions to the standard 3GPP Multicast/Broadcast Multimedia Service (MBMS) in order to improve the quality of experience of multicast/broadcast traffic services in high user-density scenarios.El crecimiento de la demanda de tasas de transmisiĂłn mĂĄs altas estĂĄ empujando a los operadores de redes mĂłviles y a los fabricantes de equipos de red a la adopciĂłn de soluciones innovadoras en ĂĄreas que se extienden desde tĂ©cnicas avanzadas de capa fĂ­sica (agregaciĂłn de portadoras, esquemas MIMO masivos, etc.) hasta la red de acceso radio y troncal, entre otras. Desde 1957 la capacidad de las redes celulares se ha multiplicado por un millĂłn. La utilizaciĂłn de mayor espectro radioelĂ©ctrico (incremento en factor 25), la divisiĂłn de dicho espectro en recursos mĂĄs pequeños (factor 5) y la introducciĂłn de esquemas avanzados de modulaciĂłn y codificaciĂłn (factor 5) han desempeñado un papel menos significativo que las mejoras en la capacidad del sistema debidas a la reducciĂłn del tamaño de las celdas (factor 1600). Este hecho justifica el interĂ©s del mundo acadĂ©mico y de la industria en estaciones base de corto alcance y baja potencia, conocidas comĂșnmente como small cells. La transiciĂłn de despliegues tradicionales de redes celulares basados en macroceldas hacia redes heterogĂ©neas pone de manifiesto la necesidad de adoptar esquemas arquitecturales y de procedimientos capaces de proporcionar una integraciĂłn transparente de despliegues masivos de small cells en la actual infraestructura de red celular. Este aspecto es particularmente complejo en el caso de despliegues a gran escala de redes inalĂĄmbricas de small cells (NoS, en sus siglas en inglĂ©s), donde la conectividad entre estaciones base se proporciona a travĂ©s de una conexiĂłn troncal inalĂĄmbrica multi-salto. En general, las redes de small cells son una soluciĂłn eficiente para mejorar la cobertura y la capacidad de la red celular en entornos de alta densidad de usuarios, como nĂșcleos de transporte, sedes de eventos deportivos, palacios de congresos, ĂĄreas urbanas densas, centros comerciales, edificios corporativos, campus universitarios, parques temĂĄticos, etc. El objetivo de esta Tesis de Doctorado es proporcionar una respuesta a la siguiente pregunta de investigaciĂłn: ÂżCuĂĄl es el esquema arquitectural y de procedimientos de red necesario para soportar mecanismos eficientes de gestiĂłn de trĂĄfico y movilidad en despliegues masivos de redes inalĂĄmbricas de small cells LTE? Para responder a esta pregunta nos centramos en tres desafĂ­os clave en NoS. En primer lugar, presentamos una arquitectura de red 3GPP capaz de soportar despliegues a gran escala de redes inalĂĄmbricas de small cells en el Evolved Packet System, esto es, el sistema global de comunicaciones celulares LTE. Esto implica delegar funciones de red troncal en nuevas entidades funcionales desplegadas en la red de small cells, asĂ­ como adaptar funcionalidades de la red de transporte a las caracterĂ­sticas de una NoS para soportar servicios celulares clave. En segundo lugar, nos centramos en el problema de la gestiĂłn de movilidad local, es decir, determinar la localizaciĂłn aproximada de un terminal mĂłvil en la NoS a la llegada de una solicitud de conexiĂłn desde la red troncal. Esto incluye el diseño, la implementaciĂłn y la evaluaciĂłn de mecanismos eficientes de paging y Tracking Area Update capaces de monitorizar terminales mĂłviles en el complejo escenario de redes de small cells inalĂĄmbricas que, a la vez, mitiguen el impacto sobre el trĂĄfico de señalizaciĂłn en el dominio local de la NoS y hacia la red troncal. Finalmente, estudiamos el problema de gestiĂłn de trĂĄfico en despliegues a gran escala de redes inalĂĄmbricas de small cells. Por un lado, proponemos nuevos procedimientos de red 3GPP para soportar comunicaciones unicast directas entre terminales LTE registrados en la misma NoS con mĂ­nima intervenciĂłn por parte de entidades funcionales en la red troncal. Por otro lado, definimos un conjunto de extensiones para mejorar la calidad de la experiencia del servicio estĂĄndar 3GPP de transmisiĂłn multicast/broadcast de trĂĄfico multimedia (MBMS, en sus siglas en inglĂ©s) en entornos de alta densidad de usuarios

    Media independent handovers : network selection for mobile IP nodes in heterogeneous wireless networks

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    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 node’s network selection by reducing the delay associated and the packet losses incurred

    A survey of self organisation in future cellular networks

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    This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks
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