82,881 research outputs found

    QoE-driven LTE Downlink Scheduling for Multimedia Services

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    The significant growth in multimedia services and traffic (e.g. VoIP, video streaming and video gaming) in current and emerging mobile networks including the latest 4G Long-Term Evolution (LTE) networks and the rising user expectation for high Quality of Experience (QoE) for these services have posed real challenges to network operators and service providers. One of the key challenges is how to bring multimedia services to the end-user over resource-constrained mobile networks with a satisfactory QoE. Cost-effective solutions are needed for network operators to improve the bandwidth usage of these mobile networks. Therefore, scheduling schemes are of extreme importance in LTE, where scheduling algorithms are responsible for the overall efficiency of resource allocation in an LTE system. The aim of the project is to develop novel QoE-driven scheduling algorithms for improving system capacity in delivering multimedia services over downlink 3GPP LTE. This is to move away from traditional QoS-driven scheduling schemes to a QoE-driven scheme which guarantee end-user satisfaction in resource allocation. The main contributions of the thesis are threefold: 1. Performance of several existing scheduling algorithms for VoIP applications was evaluated thoroughly in terms of QoE metric (i.e. MOS), instead of QoS metrics (e.g. packet loss and delay). Using QoE metrics instead of QoS ones will facilitate the development of QoE-driven scheduling schemes in order to achieve optimised end-user experiences or optimised mobile system capacity. 2. A novel QoE-driven LTE downlink scheduling scheme for VoIP application was developed to maximize the number of users per cell at an acceptable MOS score. The proposed scheme achieved significant improvement in cell capacity at an acceptable quality (75% compared to MLWDF, and 250% compared to PF and EXP-PF in all three lower speed scenarios considered). 3. A QoE-driven LTE downlink scheduling scheme for multiservice multimedia applications was developed to improve the cell capacity with satisfactory QoE for both VoIP and video streaming services. The proposed algorithm performed well in a pedestrian scenario increasing cell capacity to double for video stream with ‘Rapid Movement’ (RM) content. For ‘Medium Movement’ (MM) video content, the capacity was increased about 20% compared to MLWDF and by 40% compared to EXP-PF. In a vehicular scenario, the proposed scheme managed to enhance the cell capacity for MM video stream case. The project has led to three publications (IEEE Globecom’12 – QoEMC Workshop, IEEE CCNC’15 and IEEE MMTC E-letter/May-2015). A journal paper is in preparation.The Public Authority for Applied Education and Training , Kuwai

    Environmental Policy Formation and the Tax Treatment of Citizen Interest Groups

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    With increasing technological advancements more sophisticated mobile devices are being used by end-users. Third generation (3G) mobile communication systems such as Universal Mobile Telecommunication System (UMTS) are not able to satisfy the rising demand for higher throughputs and low latencies. New standards based on Orthogonal Frequency Division Multiplexing (OFDM), such as Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX), have been proposed and are currently being integrated into existing mobile networks all over the world. LTE specifications are being finalized within the 3rd Generation Partnership Project (3GPP) with the ambitious goals of increased spectral efficiency and end user throughput. Despite the introduction of several high data rate services, voice communication is still an essential part of the overall wireless wide area cellular communication market. In LTE, the core network is purely packet switched, thus voice is transmitted entirely using a Voice over Internet Protocol (VoIP). Like its predecessor standards it is desired that a large number of simultaneous VoIP calls be supported in LTE, while satisfying the desired Quality of Service (QoS) demands. This thesis examines issues related to VoIP capacity for LTE. One of the key challenges is the limited number of schedulable voice packets per sub frame. The main goal of this thesis is to quantify the impact of this limitation. After describing basic LTE concepts, a detailed description of the control channel resource limitations for the scheduling of voice packets is presented. Consequences of these limitations are explained systematically by presenting the problem in a wider context. Simulation results were obtained using the openWNS Simulator, an event driven system level simulation platform developed at the Communication Networks Research Group (ComNets), RWTH Aachen University Germany. Results are presented showing the impact of different scheduling strategies on VoIP capacity. These results illustrate how the limited control channel resources, specifically the Physical Downlink Control Channel (PDCCH) resources, affect the total number of schedulable VoIP user audio media streams.Med ökande tekniska framsteg mer avancerade mobila enheter som anvÀnds av slutanv Àndarna. Tredje generationens (3G) mobila kommunikationssystem sÄsom Universal Mobile Telecommunication System (UMTS) inte kan tillgodose den ökande efterfrÄgan pÄ högre genomströmning och lÄga latenser. Nya standarder som bygger pÄ Orthogonal Frequency Division Multiplexing (OFDM), sÄsom Long Term Evolution (LTE) och Worldwide Interoperability för Microwave Access (WiMAX), har föreslagits och hÄller pÄ att integreras I befintliga mobilnÀt över hela vÀrlden. LTE specifikationer hÄller pÄ att fÀrdigstÀllas inom 3rd Generation Partnership Project (3GPP) med de ambitiösa mÄlen om ökad spektral effektivitet och slutanvÀndare genomstr ömning. Trots införandet av flera tjÀnster av hög datahastighet, Àr röstkommunikation fortfarande en vÀsentlig del av den totala Wireless Wide Area cellulÀr kommunikation marknaden. I LTE Àr kÀrnnÀtet rent paketförmedlande dÀrmed röst överförs helt och hÄllet med hjÀlp av en Voice over Internet Protocol (VoIP). Precis som sina föregÄngare standarder Àr det önskvÀrt att ett stort antal samtidiga VoIP samtal fÄ stöd i LTE, samtidigt som det uppfyller önskade Quality of Service (QoS) krav. Denna avhandling undersöker frÄgor relaterade till VoIP kapacitet för LTE. En av de viktigaste utmaningarna Àr det begrÀnsade antalet schemalÀggningsbart röst paket per sub ram. Det huvudsakliga mÄlet med denna avhandling Àr att kvantifiera effekterna av denna begrÀnsning. Efter att ha beskrivit de grundlÀggande LTE begrepp, Àr en detaljerad beskrivning av de resurser kontroll kanal begrÀnsningar för schemalÀggning av röst paket presenteras. Konsekvenser av dessa begrÀnsningar förklaras systematiskt genom att presentera problemet i ett större sammanhang. Simulering resultat erhölls med hjÀlp av openWNS Simulator, en hÀndelse driven systemnivÄ simulering som utvecklats vid Communication Networks Research Group (ComNets), RWTH Aachen University Tyskland. Resultat presenteras som visar effekterna av olika schemalÀggning strategier för VoIP kapacitet. Dessa resultat illustrerar hur de begrÀnsade kontroll kanalresurser, sÀrskilt fysiskt Downlink (PDCCH) resurser, pÄverkar det totala antalet schemalÀggningsbart VoIP anvÀndare ljud mediaströmmar

    Optimization of Bi-Directional V2G Behavior With Active Battery Anti-Aging Scheduling

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