6,971 research outputs found

    Radio frequency optimization of a Global System for Mobile (GSM) network

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    Includes bibliographical references

    Characteristics of WAP traffic

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    This paper considers the characteristics of Wireless Application Protocol (WAP) traffic. We start by constructing a WAP traffic model by analysing the behaviour of users accessing public WAP sites via a monitoring system. A wide range of different traffic scenarios were considered, but most of these scenarios resolve to one of two basic types. The paper then uses this traffic model to consider the effects of large quantities of WAP traffic on the core network. One traffic characteristic which is of particular interest in network dimensioning is the degree of self-similarity, so the paper looks at the characteristics of aggregated traffic with WAP, Web and packet speech components to estimate its self-similarity. The results indicate that, while WAP traffic alone does not exhibit a significant degree of self-similarity, a combined load from various traffic sources retains almost the same degree of self-similarity as the most self-similar individual source

    A Formal Object Model for Layered Networks to Support Verification and Simulation

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    This work presents an abstract formal model of the interconnection structure of the Open Systems Interconnection Reference Model (OSI-RM) developed using Object-Oriented modeling principles permitting it to serve as a re-usable platform in supporting the development of simulations and formal methods applied to layered network protocols. A simulation of the object model using MODSIM III was developed and Prototype Verification System (PVS) was used to show the applicability of the object model to formal methods by formally specifying and verifying a Global Systems for Mobile communications (GSM) protocol. This application has proved to be successful in two aspects. The first was showing the existence of discrepancies between informal standard protocol specifications, and the second was that communication over the layered GSM network was verified. Although formal methods is somewhat difficult and time consuming, this research shows the need for the formal specification of all communication protocols to support a clear understanding of these protocols and to provide consistency in their implementations. A domain for the application of this model is mobile cellular telecommunications systems. Mobile Communications is one of the most rapidly expanding sectors of telecommunications. Expectations of what a mobile cellular phone can do have vastly increased the complexity of cellular communication networks, which makes it imperative that protocol specifications be verified before implementation

    MIPv6 Experimental Evaluation using Overlay Networks

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    The commercial deployment of Mobile IPv6 has been hastened by the concepts of Integrated Wireless Networks and Overlay Networks, which are present in the notion of the forthcoming generation of wireless communications. Individual wireless access networks show limitations that can be overcome through the integration of different technologies into a single unified platform (i.e., 4G systems). This paper summarises practical experiments performed to evaluate the impact of inter-networking (i.e. vertical handovers) on the Network and Transport layers. Based on our observations, we propose and evaluate a number of inter-technology handover optimisation techniques, e.g., Router Advertisements frequency values, Binding Update simulcasting, Router Advertisement caching, and Soft Handovers. The paper concludes with the description of a policy-based mobility support middleware (PROTON) that hides 4G networking complexities from mobile users, provides informed handover-related decisions, and enables the application of different vertical handover methods and optimisations according to context.Publicad

    Literature review of recent, practical - oriented computer networks papers

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    This thesis report is submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Electrical and Electronic Engineering, 2009.Cataloged from PDF version of thesis report.Includes bibliographical references (page 61).This thesis will include a literature review of recent practical oriented computer networks papers in premier IEEE conferences. The objective of the thesis is to provide detailed plans for a number of computer network related projects that may be implemented by subsequent BRAC University students. We will do an in-depth study of the selected topics and provide a step by step implementation process.Hasibul IslamHassan SameerIrtiza Ahmad FarooqB. Electrical and Electronic Engineerin

    Multiobjective auction-based switching-off scheme in heterogeneous networks: to bid or not to bid?

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    ©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The emerging data traffic demand has caused a massive deployment of network infrastructure, including Base Stations (BSs) and Small Cells (SCs), leading to increased energy consumption and expenditures. However, the network underutilization during low traffic periods enables the Mobile Network Operators (MNOs) to save energy by having their traffic served by third party SCs, thus being able to switch off their BSs. In this paper, we propose a novel market approach to foster the opportunistic utilization of the unexploited SCs capacity, where the MNOs, instead of requesting the maximum capacity to meet their highest traffic expectations, offer a set of bids requesting different resources from the third party SCs at lower costs. Motivated by the conflicting financial interests of the MNOs and the third party, the restricted capacity of the SCs that is not adequate to carry the whole traffic in multi-operator scenarios, and the necessity for energy efficient solutions, we introduce a combinatorial auction framework, which includes i) a bidding strategy, ii) a resource allocation scheme, and iii) a pricing rule. We propose a multiobjective framework as an energy and cost efficient solution for the resource allocation problem, and we provide extensive analytical and experimental results to estimate the potential energy and cost savings that can be achieved. In addition, we investigate the conditions under which the MNOs and the third party companies should take part in the proposed auction.Peer ReviewedPostprint (author's final draft

    Cyclist-aware intelligent transportation system

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    Abstract. Rapidly developing cities make cycling popular way of traveling around and with enhanced smart traffic light infrastructure cycling can be safer and smoother. Smartphones with an internet connectivity and advanced positioning sensors can be used to build a cost-effective infrastructure to enable cyclist-aware traffic lights system. However, such systems depends on proper time of arrival estimation which can be affected by the GPS errors which works poorly in area with tall buildings and driver behaviour. In this paper we discuss how presence of feedback from smart traffic system influence the driver awareness of the cyclist and affects the negative impact of time of arrival estimation errors. This paper gives an analysis of the existing approaches to build smart cyclist-aware traffic systems and different sources of errors that affects their performance. With designed computer appliance we evaluated the effectiveness of cyclist-aware system with and without a presence of additional haptic and audio feedback. The results show that the presence of feedback positively affects the driver awareness of cyclist and allow them to react earlier. Experiment shows that just introduction of feedback can increase the accuracy of time of arrival estimation up to 34% without any other modification to the system.Pyöräilijät tiedostava älykäs liikennejärjestelmä. Tiivistelmä. Pyöräily on suosittu tapa liikkua nopeasti kasvavissa kaupungeissa. Parannetuilla älyliikennevaloilla pyöräilystä voisi tulla turvallisempaa ja sujuvampaa. Huokean infrastruktuurin rakentamisessa pyöräilijät tiedostavaan liikennevalojärjestelmään voidaan hyödyntää älypuhelinten verkkoyhteyttä sekä pitkälle kehitettynyttä paikannusmahdollisuutta. Paikannuksen haasteena kuitenkin ovat epätarkkuus korkeiden rakennusten katveessa sekä pyöräilijöiden ja autoilijoiden käyttäytyminen. Kyseisen kaltainen järjestelmä vaatii toimivan kulunaika-arvioinnin, mikä on haastavaa GPS-paikannuksen epätarkkuuden vuoksi. Tässä julkaisussa keskustelemme siitä, kuinka älykkäästä liikennejärjestelmästä saatu palaute vaikuttaa autoilijoiden tiedostavuuteen ja sitä kautta saapumisaika-arvioiden epätarkkuuteen. Analysoimme olemassa olevia älykkäitä pyöräiljät tiedostavia liikennejärjestelmiä ja niihin vaikuttavia epätarkkuus- sekä virhelähteitä. Käytämme kehittämäämme tietokone ohjelmaa arvioimaan pyöräilijät tiedostavan järjestelmän tehokkuutta käyttäen koemuuttujina haptista ja auditiivista palautetta. Tulokset paljastavat, että saatu palaute vaikuttaa positiivisesti parantaen autoilijoiden reaktioaikaa sekä sitä kuinka he tiedostavat pyöräiljät. Kokeet osoittavat, että pelkästään esittelyn ja palautteen olemassaolo lisäävät saapumisaika-arvioiden tarkkuutta jopa 34%

    Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment

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    In the last decade, integrated logistics has become an important challenge in the development of wireless communication, identification and sensing technology, due to the growing complexity of logistics processes and the increasing demand for adapting systems to new requirements. The advancement of wireless technology provides a wide range of options for the maritime container terminals. Electronic devices employed in container terminals reduce the manual effort, facilitating timely information flow and enhancing control and quality of service and decision made. In this paper, we examine the technology that can be used to support integration in harbor's logistics. In the literature, most systems have been developed to address specific needs of particular harbors, but a systematic study is missing. The purpose is to provide an overview to the reader about which technology of integrated logistics can be implemented and what remains to be addressed in the future
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