19 research outputs found

    An optimum dynamic priority-based call admission control scheme for universal mobile telecommunications system

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    The dynamism associated with quality of service (QoS) requirement for traffic emanating from smarter end users devices founded on the internet of things (IoTs) drive, places a huge demand on modern telecommunication infrastructure. Most telecom networks, currently utilize robust call admission control (CAC) policies to ameliorate this challenge. However, the need for smarter CAC has becomes imperative owing to the sensitivity of traffic currently being supported. In this work, we developed a prioritized CAC algorithm for third Generation (3G) wireless cellular network. Based on the dynamic priority CAC (DP-CAC) model, we proposed an optimal dynamic priority CAC (ODP-CAC) scheme for Universal Mobile Telecommunication System (UMTS). We then carried out simulation under heavy traffic load while also exploiting renegotiation among different call traffic classes. Also, we introduced queuing techniques to enhance the new calls success probability while still maintaining a good handoff failure across the network. Results show that ODP-CAC provides an improved performance with regards to the probability of call drop for new calls, network load utilization and grade of service with average percentage value of 15.7%, 5.4% and 0.35% respectively

    Convergence: the next big step

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    Recently, web based multimedia services have gained popularity and have proven themselves to be viable means of communication. This has inspired the telecommunication service providers and network operators to reinvent themselves to try and provide value added IP centric services. There was need for a system which would allow new services to be introduced rapidly with reduced capital expense (CAPEX) and operational expense (OPEX) through increased efficiency in network utilization. Various organizations and standardization agencies have been working together to establish such a system. Internet Protocol Multimedia Subsystem (IMS) is a result of these efforts. IMS is an application level system. It is being developed by 3GPP (3rd Generation Partnership Project) and 3GPP2 (3rd Generation Partnership Project 2) in collaboration with IETF (Internet Engineering Task Force), ITU-T (International Telecommunication Union – Telecommunication Standardization Sector), and ETSI (European Telecommunications Standards Institute) etc. Initially, the main aim of IMS was to bring together the internet and the cellular world, but it has extended to include traditional wire line telecommunication systems as well. It utilizes existing internet protocols such as SIP (Session Initiation Protocol), AAA (Authentication, Authorization and Accounting protocol), and COPS (Common Open Policy Service) etc, and modifies them to meet the stringent requirements of reliable, real time communication systems. The advantages of IMS include easy service quality management (QoS), mobility management, service control and integration. At present a lot of attention is being paid to providing bundled up services in the home environment. Service providers have been successful in providing traditional telephony, high speed internet and cable services in a single package. But there is very little integration among these services. IMS can provide a way to integrate them as well as extend the possibility of various other services to be added to allow increased automation in the home environment. This thesis extends the concept of IMS to provide convergence and facilitate internetworking of the various bundled services available in the home environment; this may include but is not limited to communications (wired and wireless), entertainment, security etc. In this thesis, I present a converged home environment which has a number of elements providing a variety of communication and entertainment services. The proposed network would allow effective interworking of these elements, based on IMS architecture. My aim is to depict the possible advantages of using IMS to provide convergence, automation and integration at the residential level

    Adaptive scheduling in cellular access, wireless mesh and IP networks

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    Networking scenarios in the future will be complex and will include fixed networks and hybrid Fourth Generation (4G) networks, consisting of both infrastructure-based and infrastructureless, wireless parts. In such scenarios, adaptive provisioning and management of network resources becomes of critical importance. Adaptive mechanisms are desirable since they enable a self-configurable network that is able to adjust itself to varying traffic and channel conditions. The operation of adaptive mechanisms is heavily based on measurements. The aim of this thesis is to investigate how measurement based, adaptive packet scheduling algorithms can be utilized in different networking environments. The first part of this thesis is a proposal for a new delay-based scheduling algorithm, known as Delay-Bounded Hybrid Proportional Delay (DBHPD), for delay adaptive provisioning in DiffServ-based fixed IP networks. This DBHPD algorithm is thoroughly evaluated by ns2-simulations and measurements in a FreeBSD prototype router network. It is shown that DBHPD results in considerably more controllable differentiation than basic static bandwidth sharing algorithms. The prototype router measurements also prove that a DBHPD algorithm can be easily implemented in practice, causing less processing overheads than a well known CBQ algorithm. The second part of this thesis discusses specific scheduling requirements set by hybrid 4G networking scenarios. Firstly, methods for joint scheduling and transmit beamforming in 3.9G or 4G networks are described and quantitatively analyzed using statistical methods. The analysis reveals that the combined gain of channel-adaptive scheduling and transmit beamforming is substantial and that an On-off strategy can achieve the performance of an ideal Max SNR strategy if the feedback threshold is optimized. Finally, a novel cross-layer energy-adaptive scheduling and queue management framework EAED (Energy Aware Early Detection), for preserving delay bounds and minimizing energy consumption in WLAN mesh networks, is proposed and evaluated with simulations. The simulations show that our scheme can save considerable amounts of transmission energy without violating application level QoS requirements when traffic load and distances are reasonable

    Dimensioning mobile WiMAX in the access and core network : a case study

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    Existing broadband wireless technologies such as evolving 3G and WiFi have enjoyed widespread adoption but are far from offering the flexibility in deployment and high data rates. Mobile WiMAX, an emerging broadband wireless technology promises to bring a new experience to mobile broadband services by offering users high data rates and efficient network access techniques. This thesis work provides a technical description of mobile WiMAX and compares its technical capabilities with the existing technologies such as WiFi and 3G. The work continues further on dimensioning mobile WiMAX in the access and core network. In the access network, we determine the number of base stations required to cover a given metropolitan area, explore their configurations, and perform frequency selection. In the core network we dimension the interfaces, and nodes involved. From the study we will show that WiMAX provides the operator with the antenna configurations options of high capacities, large cell coverage area, and a wide selection of QoS classes. The study will also show that the data density requirements of customers, resulting from the capacity analysis are fulfilled by properly dimensioning the elements in the access and core network

    QoS provisioning and mobility management for IP-based wireless LAN

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    Today two major technological forces drive the telecommunication era: the wireless cellular systems and the Internet. As these forces converge, the demand for new services, increasing bandwidth and ubiquitous connectivity continuously grows. The next-generation mobile systems will be based solely or in a large extent, on the Internet Protocol (IP). This thesis begins by addressing the problems and challenges faced in a multimedia, IP-based Wireless LAN environment. The ETSI HiperLAN/2 system has been mainly selected as the test wireless network for our theoretical and simulation experiments. Apart from the simulations, measurements have been taken from real life test scenarios, where the IEEE 802.11 system was used (UniS Test-bed). Furthermore, a brief overview of the All-IP network infrastructure is presented. An extension to the conventional wireless (cellular) architecture, which takes advantage of the IP network characteristics, is considered. Some of the trends driving the 3G and WLANs developments are explored, while the provision of quality of service on the latter for real-time and non-real-time multimedia services is investigated, simulated and evaluated. Finally, an efficient and catholic Q0S framework is proposed. At the same time, the multimedia services should be offered in a seamless and uninterrupted manner to users who access the all-IP infrastructure via a WLAN, meeting the demands of both enterprise and public environments anywhere and anytime. Thus providing support for mobile communications not only in terms of terminal mobility, as is currently the case, but also for session, service and personal mobility. Furthermore, this mobility should be available over heterogeneous networks, such as WLANs, IJMTS, as well as fixed networks. Therefore, this work investigates issues such as, multilayer and multi-protocol (SIP-Mobile IP-Cellular IP) mobility management in wireless LAN and 3G domains. Several local and global mobility protocols and architectures have been tested and evaluated and a complete mobility management framework is proposed. Moreover, integration of simple yet efficient authentication, accounting and authorisation mechanisms with the multimedia service architecture is an important issue of IP-based WLANs. Without such integration providers will not have the necessary means to control their provided services and make revenue from the users. The proposed AAA architecture should support a robust AAA infrastructure providing secure, fast and seamless access granting to multimedia services. On the other hand, a user wishing a service from the All-IP WLAN infrastructure needs to be authenticated twice, once to get access to the network and the other one should be granted for the required service. Hence, we provide insights into these issues by simulating and evaluating pre-authentication techniques and other network authentication scenarios based on the wellknown IEEE 802.lx protocol for multimedia IP-based WLANs.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Resource allocation for end-to-end QoS provisioning in a hybrid wireless WCDMA and wireline IP-based DiffServ network

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    In the future UMTS network, the heterogeneous traffics of multimedia services demand various QoS provisioning. At the same time, the seamlessly conveying of information between mobile users and a hybrid network requires the networking from wireless to wireline domains. However, in both academia and industries, the end-to-end QoS provisioning in the integration of wireline and wireless networks remains a challenge. In this paper, a modeling of a hybrid wireless WCDMA and wireline IP-based DiffServ network is presented to investigate the resource allocation for end-to-end QoS provisioning for multimedia services. In the wireless domain, the mathematical modeling of the cross-layer model including the physical layer, the link layer and the network layer is built. The connection admission control scheme is implemented based on the cross-layer model to determine the amount of resource for different services. In the wireline domain, we define the mapping of QoS classes between UMTS and DiffServ networks according to different QoS requirements. We propose a bandwidth allocation scheme to provide satisfactory packet loss and delay guarantee in DiffServ networks. The final end-to-end admission control scheme combines the resource allocation and admission control in both wireless and wireline domains. The analytical and simulation results show that the proposed resource allocation and admission control schemes work cooperatively in the presented hybrid wireless and wireline networks to guarantee the end-to-end QoS requirements for multimedia services.

    The strategies associated with the migration of networks to 4G

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    The networks need to provide higher speeds than those offered today. For it, considering that in the spectrum radio technologies is the scarcest resource in the development of these technologies and the new developments is essential to maximize the performance of bits per hertz transmitted. Long Term Evolution optimize spectral efficiency modulations with new air interface, and more advanced algorithms radius. These capabilities is the fact that LTE is an IPbased technology that enables end-to-end offer high transmission rates per user and very low latency, ie delay in the response times of the network around only 10 milliseconds, so you can offer any realtime application. LTE is the latest standard in mobile network technology and 3GPP ensure competitiveness in the future, may be considered a technology bridge between 3G networks - current 3.5G and future 4G networks, which are expected to reach speeds of up to 1G . LTE operators provide a simplified architecture but both robust, supporting services on IP technology. The objectives to be achieved through its implementation are ambitious, first users have a wide range of added services like capabilities that currently enjoys with residential broadband access at competitive prices, while the operator will have a network fully IP-based environment, reducing the complexity and cost of the same, which will give operators the opportunity to migrate to LTE directly. A major advantage of LTE is its ability to fuse with existing networks, ensuring interconnection with the same, increasing his current coverage and allowing a data connection established by a user in the environment continue when fade the coverage LTE. Moreover, the operator has the advantage of deploying network gradually, starting initially at areas of high demand for broadband services and expand progressively in line with this. RESUMEN. Las redes necesitan proporcionar velocidades mayores a las ofertadas a día de hoy. Para ello, teniendo en cuenta que en tecnologías radio el espectro es el recurso más escaso, en la evolución de estas tecnologías y en los nuevos desarrollos es esencial maximizar el rendimiento de bits por hercio transmitido. Long Term Evolution optimiza la eficiencia espectral con nuevas modulaciones en la interfaz aire, así como los algoritmos radio más avanzado. A estas capacidades se suma el hecho de que LTE es una tecnología basada en IP de extremo a extremo que permite ofrecer altas velocidades de transmisión por usuario y latencias muy bajas, es decir, retardos en los tiempos de respuesta de la red en torno a sólo 10 milisegundos, por lo que permite ofrecer cualquier tipo de aplicación en tiempo real. LTE es el último estándar en tecnología de redes móviles y asegurará la competitividad de 3GPP en el futuro, pudiendo ser considerada una tecnología puente entre las redes 3G – 3.5G actuales y las futuras redes 4G, de las que se esperan alcanzar velocidades de hasta 1G. LTE proporcionará a las operadoras una arquitectura simplificada pero robusta a la vez, soportando servicios sobre tecnología IP. Los objetivos que se persiguen con su implantación son ambiciosos, por una parte los usuarios dispondrá de una amplia oferta de servicios añadidos con capacidades similares a las que disfruta actualmente con accesos a banda ancha residencial y a precios competitivos, mientras que el operador dispondrá de una red basada en entorno totalmente IP, reduciendo la complejidad y el costo de la misma, lo que dará a las operadoras la oportunidad de migrar a LTE directamente. Una gran ventaja de LTE es su capacidad para fusionarse con las redes existentes, asegurando la interconexión con las mismas, aumentando su actual cobertura y permitiendo que una conexión de datos establecida por un usuario en el entorno LTE continúe cuando la cobertura LTE se desvanezca. Por otra parte el operador tiene la ventaja de desplegar la red LTE de forma gradual, comenzando inicialmente por las áreas de gran demanda de servicios de banda ancha y ampliarla progresivamente en función de ésta

    Quality of service differentiation for multimedia delivery in wireless LANs

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    Delivering multimedia content to heterogeneous devices over a variable networking environment while maintaining high quality levels involves many technical challenges. The research reported in this thesis presents a solution for Quality of Service (QoS)-based service differentiation when delivering multimedia content over the wireless LANs. This thesis has three major contributions outlined below: 1. A Model-based Bandwidth Estimation algorithm (MBE), which estimates the available bandwidth based on novel TCP and UDP throughput models over IEEE 802.11 WLANs. MBE has been modelled, implemented, and tested through simulations and real life testing. In comparison with other bandwidth estimation techniques, MBE shows better performance in terms of error rate, overhead, and loss. 2. An intelligent Prioritized Adaptive Scheme (iPAS), which provides QoS service differentiation for multimedia delivery in wireless networks. iPAS assigns dynamic priorities to various streams and determines their bandwidth share by employing a probabilistic approach-which makes use of stereotypes. The total bandwidth to be allocated is estimated using MBE. The priority level of individual stream is variable and dependent on stream-related characteristics and delivery QoS parameters. iPAS can be deployed seamlessly over the original IEEE 802.11 protocols and can be included in the IEEE 802.21 framework in order to optimize the control signal communication. iPAS has been modelled, implemented, and evaluated via simulations. The results demonstrate that iPAS achieves better performance than the equal channel access mechanism over IEEE 802.11 DCF and a service differentiation scheme on top of IEEE 802.11e EDCA, in terms of fairness, throughput, delay, loss, and estimated PSNR. Additionally, both objective and subjective video quality assessment have been performed using a prototype system. 3. A QoS-based Downlink/Uplink Fairness Scheme, which uses the stereotypes-based structure to balance the QoS parameters (i.e. throughput, delay, and loss) between downlink and uplink VoIP traffic. The proposed scheme has been modelled and tested through simulations. The results show that, in comparison with other downlink/uplink fairness-oriented solutions, the proposed scheme performs better in terms of VoIP capacity and fairness level between downlink and uplink traffic
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