116 research outputs found
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Performance measurements and analysis of the existing wireless communication technology in Iraq.
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityIraq may be considered as the largest wireless market in the Gulf region. A key driving factor in the market of wireless communication, it has seen enormous growth in the mobile phone market over the last five years leading to almost 24 million subscribers in 2011. Moreover, there are several technologies and services working in Iraq; three GSM Operators, three CDMA national operators and three CDMA provinces operators. The recent growth in the mobile phone market is based on the Global System for Mobile (GSM) communications and Code Division Multiple Access (CDMA) standards creating the next-generation wireless technologies in the Iraqi Wireless Communication market. One of the essential issues of this research is to investigate the performance of the decreased Quality Of Service (QoS) caused by interferences in the services on GSM/CDMA operators in Iraq. Many issues should be studied and taken into consideration, such as; does the Multi-Coalition Forces cause the interferences, jamming, higher rate of calls drop and false ringing; or are they caused by bad design and planning? Do we need to optimise our network due to the large number of users? All these factors are investigated and the measurements of most service providers and government agencies will be gathered. A detailed analysis was included from the providers with measurements of performance and the reasons for the deterioration of wireless services. The novel contributions of this thesis is the extensive radio measurement campaign over the three mobile an CDMA operator networks and the analysis and recommendations that were drawn to suggest the best approach to improve the QoS of Wireless communication technologies. Awareness of actual reasons behind the deterioration of services will be raised to the Iraqi Government, CMC and the wireless service providers
Reliable and Low-Latency Fronthaul for Tactile Internet Applications
With the emergence of Cloud-RAN as one of the dominant architectural
solutions for next-generation mobile networks, the reliability and latency on
the fronthaul (FH) segment become critical performance metrics for applications
such as the Tactile Internet. Ensuring FH performance is further complicated by
the switch from point-to-point dedicated FH links to packet-based multi-hop FH
networks. This change is largely justified by the fact that packet-based
fronthauling allows the deployment of FH networks on the existing Ethernet
infrastructure. This paper proposes to improve reliability and latency of
packet-based fronthauling by means of multi-path diversity and erasure coding
of the MAC frames transported by the FH network. Under a probabilistic model
that assumes a single service, the average latency required to obtain reliable
FH transport and the reliability-latency trade-off are first investigated. The
analytical results are then validated and complemented by a numerical study
that accounts for the coexistence of enhanced Mobile BroadBand (eMBB) and
Ultra-Reliable Low-Latency (URLLC) services in 5G networks by comparing
orthogonal and non-orthogonal sharing of FH resources.Comment: 11pages, 13 figures, 3 bio photo
Quality-of-service in wireless sensor networks: state-of-the-art and future directions
Wireless sensor networks (WSNs) are one of todayâs most prominent instantiations
of the ubiquituous computing paradigm. In order to achieve high
levels of integration, WSNs need to be conceived considering requirements
beyond the mere systemâs functionality. While Quality-of-Service (QoS) is
traditionally associated with bit/data rate, network throughput, message delay
and bit/packet error rate, we believe that this concept is too strict, in
the sense that these properties alone do not reflect the overall quality-ofservice
provided to the user/application. Other non-functional properties
such as scalability, security or energy sustainability must also be considered
in the system design. This paper identifies the most important non-functional
properties that affect the overall quality of the service provided to the users,
outlining their relevance, state-of-the-art and future research directions
The use of BGAN to implement a robust tsunami early warning system
A tsunami is a series of waves created when a body of water, such as an ocean, is rapidly displaced probably by an oceanic earthquake. The effects of a tsunami for the population can be devastating due to the immense volumes of water and energy involved.The EU-funded Distant Early Warning System (DEWS) project is currently implementing a reference model for a national and regional warning dissemination system of possible hazards or disasters, especially in the prevention of tsunamis. In DEWS several universities and companies are participating specially coming from Europe and from the three countries of interest Sri Lanka, Indonesia and Thailand.The Department of Communications and Networking of the Helsinki University of Technology (TKK) is a consortium member of the DEWS project working on the development of the communications architecture between the different Emergency Centres, first responders and general public.In this thesis report we present the implementation of a backup satellite communications system between DEWS centres and governmental authorities in order to enable the warning dissemination in case the terrestrial communication structures are disrupted due to the hazard effects.The backup communications structure would employ the BGAN Inmarsat service for the date transmission. BGAN ensures the coverage in almost global earth area and support mobility on its terminals, offering adequate characteristics for an emergency communications system. To that end, we design and describe this communications architecture and discuss its performance in the possible scenarios based on simulations
Qualidade de serviço em redes IEEE 802.16 com topologia em malha
Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesO IEEE 802.16 apresenta-se actualmente como a tecnologia mais avançada e aliciante para o acesso de banda larga metropolitano. A sua topologia pontomultiponto (PMP) foi desenvolvida desde o inĂcio com suporte para qualidade
de serviço (QoS) gerida pelo controlador ou operador da rede, podendo assim complementar, as actuais soluçÔes mĂłveis de terceira geração. Por outro lado, a topologia opcional âem malhaâ (Mesh) permite a criação de redes autoconfigurĂĄveis e com encaminhamento de trĂĄfego atravĂ©s de vĂĄrios pontos da rede. No entanto, as especificaçÔes e mecanismos de QoS apresentados na norma nĂŁo sĂŁo consistentes para estes dois modos de operação. Com a presente dissertação pretende-se estudar e avaliar uma arquitectura de QoS para o modo Mesh, baseada nos mecanismos delineados para a topologia
PMP, permitindo a coexistĂȘncia dos dois modos de operação. A arquitectura apresentada foca-se numa gestĂŁo eficiente da largura de banda utilizando mensagens de controlo ao nĂvel MAC introduzidas pelo standard IEEE 802.16.
Os resultados obtidos mostram a eficiĂȘncia das classes de serviço implementadas, convergindo com os requisitos de QoS do modo PMP.
ABSTRACT: The IEEE 802.16 standard is by now the most advanced and attractive technology for the metropolitan broadband access. The point-to-multipoint (PMP) topology was developed from the beginning with quality of service (QoS)
support, managed by the network operator, thus complementing the existing third-generation mobile solutions. On the other hand, the alternative Mesh
topology allows the creation of self-configuring networks with traffic routing through various nodes. However, the QoS specifications and mechanisms
presented in the standard are not consistent for these two operation modes.
The present work aims to study and evaluate a QoS architecture for the Mesh mode, based on mechanisms designed to PMP and thus allowing the coexistence of the two operation modes. The proposed architecture focuses on an efficient network bandwidth management, using control messages at the MAC level as suggested in the IEEE 802.16 standard. The results show the
efficiency of the implemented service classes, coming to a convergence with the quality requirements announced by PMP mode
Structural conditions for business model design in new information and communication services : a case study of multi-play and MVolP in Denmark and Norway
The report analyses the structural conditions for the design of business models regarding new information and communication services. The services examined are mobile VoIP (MVoIP) and multi-play â services that already are on the market, however in their infancy, and which represent different kinds of services in terms of structural conditions market-wise and in regulatory terms. As the two service categories are relatively new on the market, dominating business model designs have not yet settled and the strategic choices of companies are very open. Being on the market, the discussion on the business model design, however, transcends the purely speculative stage. The structural conditions studied are the market conditions including the regulatory conditions. In addition, the different technological solutions are examined, as MVoIP as well as multi-play include different technology solutions for the delivery of services to users. This means that the analysis includes technological as well as market-based and regulatory elements. The aim of the analysis of the structural conditions is two-fold: On the one hand, to deepen the understanding of the structural condition and, on the other hand, to discuss the conditions for different business model design options. The report examines the regulatory policies and market characteristics in MVoIP and multi-play as a basis for a discussion on how these policies and characteristics affect the business model decisions of service providers in the two areas. Using empirical material from Norway and Denmark, the report presents a comparative analysis of the structural conditions and the business model choices made by actors in the market. The basic theoretical framework for the analysis is the Structure-Conduct-Performance (SCP) framework. The strength of this framework is that it stretches all the way from the structural conditions, through the conduct (business models and strategies) of companies seen in connection with these structural conditions, to the actual performance of companies in the market. The focus of the present report is on the structural conditions with a view to the framework that these conditions constitute for the business model design of companies. The empirical basis of the report consists primarily of interviews with representatives from IT and telecom industry organizations, policy makers and regulators in the telecom area in Norway and Denmark
Energy-efficient bandwidth reservation for bulk data transfers in dedicated wired networks
International audienceThe ever increasing number of Internet connected end-hosts call for high performance end-to-end networks leading to an increase in the energy consumed by the networks. Our work deals with the energy consumption issue in dedicated network with bandwidth provisionning and in-advance reservations of network equipments and bandwidth for Bulk Data transfers. First, we propose an end-to-end energy cost model of such networks which described the energy consumed by a transfer for all the crossed equipments. This model is then used to develop a new energy-aware framework adapted to Bulk Data Transfers over dedicated networks. This framework enables switching off unused network portions during certain periods of time to save energy. This framework is also endowed with prediction algorithms to avoid useless switching off and with adaptive scheduling management to optimize the energy used by the transfers. 1 Introductio
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Investigation of efficient resource allocation schemes for WiMAX networks
This thesis was submitted for the degree of Master of Philosophy and was awarded by Brunel University on 9 July 2008.WiMax (Worldwide Interoperability for Microwave Access) is a promising wireless technology with the aim of providing the last mile wireless broadband access designed for both fixed and mobile consumers as an alternative solution to the wired DSL and cable access schemes. The purpose of this research project is to investigate efficient resource allocation algorithms for WiMax. To achieve this goal, we investigate efficient PHY layer Partial Usage of SubCarriers (PUSC) allocation as well as MAC layer piggyback bandwidth request mechanisms. At the PHY layer we proposed improvements on the Uplink and Downlink PUSC subcarrier allocation scheme. For the Uplink PUSC we suggested a method by allocating different frequencies to neighbouring cells in combination with the Integer Frequency Reuse (IFR) and Fractional Frequency Reuse (FFR) in order to reduce interferences and collisions. The simulation results exhibit that collision rates can be reduced to zero for both IFR and FFR patterns with the proposed improvement by assuming that perfect power control is used in the system. In addition, there is no collision at cell edges. The results also show that FFR patterns achieve lower inter-cell interference and higher capacities as compared to the IFR patterns. For the Downlink PUSC we introduced an offset scheme with the purpose of increasing the number of users in the system. At the MAC layer we propose an improvement on the piggyback bandwidth request mechanism by increasing the size of the piggyback bandwidth request in order to reduce the number of bandwidth requests and hence improve the resource utilisation. The simulation results demonstrate that our improved scheme achieves higher throughput, less delay and packet loss rates as compared to the standardised piggyback bandwidth request mechanism
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