318 research outputs found

    Handover Mechanisms in ATM-based Mobile Systems

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    This paper presents two handover mechanisms that can be used in the access part of an ATM-based mobile system. The first handover mechanism, which is called Âżhandover synchronised switchingÂż is relatively simple and does not use any ATM multicasting or resynchronisation in the network. It assumes that there is sufficient time available such that all data and history information of the old path can be transferred to the mobile terminal (MT) before the actual handover to the new path takes place. It is possible that the time between a handover decision and the actual handover is too short to end the transmission on the old path gracefully (e.g., ending the interleaving matrix, ending transcoder functions, emptying intermediate buffers). A possible solution to this problem is given by the second handover mechanism, where multicast connections to all possible target radio systems (RAS) are used in the core network. This mechanism is called Âżhandover with multicast support

    Comparative study between the generations of mobile communication 2G, 3G & 4G

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    Communication system has evolved from wired button telephone system to wireless mobile phone in the few years . With wider use of mobile communication which provides an easement to fast and easy communication mode. The study is on the comparative study between the 3 generations of mobile communication 2G, 3G & 4G. About the various data handling capacity of the three generation of mobile communication along with the services provided and basic technology behind the

    Performance Comparison of Handover Rerouting Schemes in Wireless ATM Networks

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    The major issue of the integration of wireless and wired ATM is the support of user mobility. In effect, many technical challenges have been posed due to mobility support. One of the most important challenges is the rerouting of active connections of mobile user during handover. The rerouting of connections must exhibit low handover latency, limit the handover delay or disruption time, maintain efficient routes and minimise the impact on existing infrastructure. To date, two dominant approaches have been proposed to support mobility into fixed ATM network. The first is the mobility enhanced switches approach and the second is the separate network-elements specific to mobility approach. The first approach implies updating the existing ATM switches with mobile specific features. The mobility functions in the second approach are entrusted to a control station attached to the ATM switch as is implemented by the Magic WAND projects. In this thesis, we investigate how mobility can be supported using both approaches. To demonstrate the effectiveness of the above approaches, we compare the performance by analytically derived formulate for their hand over latency, hand over delay, buffer size, and bandwidth requirements. The formulate were derived for both backward and forward hand overs using a number of potential rerouting schemes proposed for wireless ATM network. The results show that the mobility enhanced switches approach has slightly better performance than the separate network elements approach. The results also show that backward handover has better performance than forward handover in terms of the handover delay and buffer requirement. Finally, the results show that the Anchor Switch rerouting scheme is the best among other rerouting schemes proposed for wireless ATM

    Flat Cellular (UMTS) Networks

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    Traditionally, cellular systems have been built in a hierarchical manner: many specialized cellular access network elements that collectively form a hierarchical cellular system. When 2G and later 3G systems were designed there was a good reason to make system hierarchical: from a cost-perspective it was better to concentrate traffic and to share the cost of processing equipment over a large set of users while keeping the base stations relatively cheap. However, we believe the economic reasons for designing cellular systems in a hierarchical manner have disappeared: in fact, hierarchical architectures hinder future efficient deployments. In this paper, we argue for completely flat cellular wireless systems, which need just one type of specialized network element to provide radio access network (RAN) functionality, supplemented by standard IP-based network elements to form a cellular network. While the reason for building a cellular system in a hierarchical fashion has disappeared, there are other good reasons to make the system architecture flat: (1) as wireless transmission techniques evolve into hybrid ARQ systems, there is less need for a hierarchical cellular system to support spatial diversity; (2) we foresee that future cellular networks are part of the Internet, while hierarchical systems typically use interfaces between network elements that are specific to cellular standards or proprietary. At best such systems use IP as a transport medium, not as a core component; (3) a flat cellular system can be self scaling while a hierarchical system has inherent scaling issues; (4) moving all access technologies to the edge of the network enables ease of converging access technologies into a common packet core; and (5) using an IP common core makes the cellular network part of the Internet

    Energy Efficient Relay-Assisted Cellular Network Model using Base Station Switching

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    Cellular network planning strategies have tended to focus on peak traffic scenarios rather than energy efficiency. By exploiting the dynamic nature of traffic load profiles, the prospect for greener communications in cellular access networks is evolving. For example, powering down base stations (BS) and applying cell zooming can significantly reduce energy consumption, with the overriding design priority still being to uphold a minimum quality of service (QoS). Switching off cells completely can lead to both coverage holes and performance degradation in terms of increased outage probability, greater transmit power dissipation in the up and downlinks, and complex interference management, even at low traffic loads. In this paper, a cellular network model is presented where certain BS rather than being turned off, are switched to low-powered relay stations (RS) during zero-to-medium traffic periods. Neighbouring BS still retain all the baseband signal processing and transmit signals to corresponding RS via backhaul connections, under the assumption that the RS covers the whole cell. Experimental results demonstrate the efficacy of this new BS-RS Switching technique from both an energy saving and QoS perspective, in the up and downlinks

    Proposal and analysis of integrated PTN architecture in the mobile backhaul to improve the QoS of HetNets

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    Los rĂĄpidos avances de las tecnologĂ­as de dispositivos mĂłviles han implicado que la red de acceso debe evolucionar y desarrollar nuevas estrategias para satisfacer las necesidades de los usuarios. La red heterogĂ©nea (HetNet) permite una estrategia de implementaciĂłn flexible y ofrece soluciones econĂłmicamente viables para mejorar la escalabilidad de red y cobertura en interiores. Este tema emergente ha captado la atenciĂłn de la comunidad cientĂ­fica y la industria debido a la importancia de estas redes para satisfacer la demanda de servicios de datos. Para proporcionar esta demanda, deben satisfacerse diferentes parĂĄmetros de calidad de servicio (QoS). En este trabajo, presentamos un estudio sobre los Ășltimos avances y los temas de investigaciĂłn sobre movilidad en conjunciĂłn con protocolos de conmutaciĂłn de etiquetas multiprotocolo (MPLS) de paquetes basado en redes de transporte (PTN) para proporcionar QoS en redes heterogĂ©neas inalĂĄmbricas. Se presentan diversos protocolos de gestiĂłn mĂłvil y su interacciĂłn con la red de retorno mĂłvil yred bĂĄsica por paquetes. Una nueva arquitectura denominada Proxy integrado Mobile MPLS-TP (MIP-TP) se expone tambiĂ©n a reducir los costos y mejorar la señalizaciĂłn de la QoS en HetNets con altas tasas de movilidad.The rapid progress made in mobile device technologies has implied that the access network must evolute and develop new strategies to satisfy the requirements of the users. Heterogeneous network (HetNet) allows for a flexible deployment strategy and offers economically viable solutions to improve network scalability and indoor coverage. This emerging topic has caught the attention of the research community and the industry because of the importance of these networks to satisfy the demand of data services. To provide this demand, different parameters of quality of service (QoS) must be satisfied. In this paper, we present a study on recent advances and open research issues on Mobility Protocols in conjunction with Multi-Protocol Label Switching (MPLS)-based packet transport networks (PTN) to provide QoS in wireless heterogeneous networks. Various mobile management protocols and their interaction with the mobile backhaul and packet core network are briefly introduced. A new architecture called Integrated Proxy Mobile MPLS-TP (IPM-TP) is also outlined to reduce the signalling cost and improve the QoS in HetNets with high rates of mobility.UniĂłn Europea. Fondos Europeos de Desarrollo Regional (FEDER). Proyecto SOE4/P3/E804peerReviewe

    Optimization and Performance Analysis of High Speed Mobile Access Networks

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    The end-to-end performance evaluation of high speed broadband mobile access networks is the main focus of this work. Novel transport network adaptive flow control and enhanced congestion control algorithms are proposed, implemented, tested and validated using a comprehensive High speed packet Access (HSPA) system simulator. The simulation analysis confirms that the aforementioned algorithms are able to provide reliable and guaranteed services for both network operators and end users cost-effectively. Further, two novel analytical models one for congestion control and the other for the combined flow control and congestion control which are based on Markov chains are designed and developed to perform the aforementioned analysis efficiently compared to time consuming detailed system simulations. In addition, the effects of the Long Term Evolution (LTE) transport network (S1and X2 interfaces) on the end user performance are investigated and analysed by introducing a novel comprehensive MAC scheduling scheme and a novel transport service differentiation model

    Energy-efficient wireless communication

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    In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters

    Review of network integration techniques for mobile broadband services in next generation network

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    Next Generation Network (NGN) is intended at integrating the existing heterogeneous wireless access networks in order to produce a composite network that provides users with ubiquitous broadband experience. Currently, it has been established that Long Term Evolution (LTE) network, as a backbone network, provides broadband capacity with high efficiency, reduced latency and improved resource provisioning. Resource provisioning on this backbone network is not without its limitation as more mobile broadband services (MBBs) are evolving and users demand for mobility is on the increase. This paper, therefore, reviewed the different integration techniques for the heterogeneous networks that use LTE network as backbone that supports mobile broadband services.Keywords: MBB, NGN, LTE, SIP, Qo
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