187 research outputs found

    Portfolio peak algorithms achieving superior performance for maximizing throughput in WiMAX networks

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    The Mobile WiMAX IEEE 802.16 standards ensure provision of last mile wireless access, variable and high data rate, point to multi-point communication, large frequency range and QoS (Quality of Service) for various types of applications. The WiMAX standards are published by the Institute of Electric and Electronic Engineers (IEEE) and specify the standards of services and transmissions. However, the way how to run these services and when the transmission should be started are not specified in the IEEE standards and it is up to computer scientists to design scheduling algorithms that can best meet the standards. Finding the best way to implement the WiMAX standards through designing efficient scheduler algorithms is a very important component in wireless systems and the scheduling period presents the most common challenging issue in terms of throughput and time delay. The aim of the research presented in this thesis was to design and develop an efficient scheduling algorithm to provide the QoS support for real-time and non-real-time services with the WiMAX Network. This was achieved by combining a portfolio of algorithms, which will control and update transmission with the required algorithm by the various portfolios for supporting QoS such as; the guarantee of a maximum throughput for real-time and non-real-time traffic. Two algorithms were designed in this process and will be discussed in this thesis: Fixed Portfolio Algorithms and Portfolio Peak Algorithm. In order to evaluate the proposed algorithms and test their efficiency for IEEE 802.16 networks, the authors simulated the algorithms in the NS2 simulator. Evaluation of the proposed Portfolio algorithms was carried out through comparing its performance with those of the conventional algorithms. On the other hand, the proposed Portfolio scheduling algorithm was evaluated by comparing its performance in terms of throughput, delay, and jitter. The simulation results suggest that the Fixed Portfolio Algorithms and the Portfolio Peak Algorithm achieve higher performance in terms of throughput than all other algorithms. Keywords: WiMAX, IEEE802.16, QoS, Scheduling Algorithms, Fixed Portfolio Algorithms, and Portfolio Peak Algorithms.The Mobile WiMAX IEEE 802.16 standards ensure provision of last mile wireless access, variable and high data rate, point to multi-point communication, large frequency range and QoS (Quality of Service) for various types of applications. The WiMAX standards are published by the Institute of Electric and Electronic Engineers (IEEE) and specify the standards of services and transmissions. However, the way how to run these services and when the transmission should be started are not specified in the IEEE standards and it is up to computer scientists to design scheduling algorithms that can best meet the standards. Finding the best way to implement the WiMAX standards through designing efficient scheduler algorithms is a very important component in wireless systems and the scheduling period presents the most common challenging issue in terms of throughput and time delay. The aim of the research presented in this thesis was to design and develop an efficient scheduling algorithm to provide the QoS support for real-time and non-real-time services with the WiMAX Network. This was achieved by combining a portfolio of algorithms, which will control and update transmission with the required algorithm by the various portfolios for supporting QoS such as; the guarantee of a maximum throughput for real-time and non-real-time traffic. Two algorithms were designed in this process and will be discussed in this thesis: Fixed Portfolio Algorithms and Portfolio Peak Algorithm. In order to evaluate the proposed algorithms and test their efficiency for IEEE 802.16 networks, the authors simulated the algorithms in the NS2 simulator. Evaluation of the proposed Portfolio algorithms was carried out through comparing its performance with those of the conventional algorithms. On the other hand, the proposed Portfolio scheduling algorithm was evaluated by comparing its performance in terms of throughput, delay, and jitter. The simulation results suggest that the Fixed Portfolio Algorithms and the Portfolio Peak Algorithm achieve higher performance in terms of throughput than all other algorithms. Keywords: WiMAX, IEEE802.16, QoS, Scheduling Algorithms, Fixed Portfolio Algorithms, and Portfolio Peak Algorithms

    Security-centric analysis and performance investigation of IEEE 802.16 WiMAX

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    A Review on Provisioning Quality of Service of Wireless Telemedicine for E-Health Services

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    In general, on-line medical consultation reduces time required for medical consultation induces improvement in the quality and efficiency of healthcare services. All major types of current e-health applications such as ECG, X-ray, video, diagnosis images and other common applications have been included in the scope of the study. In addition, the provision of Quality of Service (QoS) for the application of specific healthcare services in e-health, the scheme of priority for e-health services and the support of QoS in wireless networks and techniques or methods for IEEE 802.11 to guarantee the provision of QoS has also been assessed. In e-health, medical services in remote locations such as rural healthcare centers, ambulances, ships as well as home healthcare services can be supported through the applications of e-health services such as medical databases, electronic health records and the routing of text, audio, video and images. Given this, an adaptive resource allocation for a wireless network with multiple service types and multiple priorities have been proposed. For the provision of an acceptable QoS level to users of e-health services, prioritization is an important criterion in a multi-traffic network. The requirement for QoS provisioning in wireless broadband medical networks have paved the pathway for bandwidth requirements and the real-time or live transmission of medical applications. From the study, good performance of the proposed scheme has been validated by the results obtained. The proposed wireless network is capable of handling medical applications for both normal and life-threatening conditions as characterized by the level of emergencies. In addition, the bandwidth allocation and admission control algorithm for IEEE 802.16- based design specifically for wireless telemedicine/e-health services have also been presented in the study. It has been concluded that under busy traffic conditions, the proposed architecture can used as a feasible and reliable infrastructure network for telemedicine

    Network Simulation and Performance Evaluation of WiMAX Extensions for Isolated Research Data Networks

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    IEEE 802.16 is yet a very recent technology and released hardware does frequently only support standards partially. The same applies to public available simulation tools, in particular for NS-2. As the latter is the de-facto standard in science and as we use it for our research in the context of the WEIRD project, we evaluate the IEEE 802.16 support for NS-2. We present several general but also specific issues, which areimportant in order to carry out reliable research based on thesetools. In particular, we show in much detail where modulesdeviate significantly and even fail totally

    Hybrid wireless broadband networks

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    A hybrid system is an integration of two or more different systems, particularly in this thesis referring to wireless broadband networks. However, to provide end-to-end quality of service (QoS) in a hybrid system is a challenging task due to different protocol in each system. In this thesis, we aim to improve the overall performance of hybrid networks in a disaster management by addressing the challenges as well as the problems in a homogeneous network. Such an approach allows more efficient multi-parameter optimization and significant improvements in the overall system performance. More specifically, we introduce two novel algorithms. The first is the novel end-to-end QoS algorithm for hybrid wireless broadband networks. We proposed the end-to-end QoS maps based on particular chosen parameters and analyse the simulation results. The QoS maps are applied to a few scenarios, and the performance evaluation of the constructed network is presented. Based on the results obtained by software simulation tools, the performance validation shows that the hybrid network has specific advantages and constraints in terms of number of users, preference, coverage and applications. The second algorithm presented is the novel in users’ application algorithm, the purpose of which is to optimize bandwidth for first responders applied in the PPDR project under grant agreement EU FP7 SEC PPDR-TC. This algorithm is responsible for incorporating more users and different levels of background load to a hybrid network. The proposed method analyses both positive and negative outcomes based on the results obtained. This algorithm has been presented in the PPDR project

    Ad-hoc wireless networking for supporting on-site communication

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    Ad-hoc networks are self-organized wireless networks. They have the potential to be widely used in emergency salvation, construction sites, and military fields. However, the research about the efficient usage of ad-hoc networking in engineering applications is still limited. In this research, a new approach for investigating problems related to deploying ad-hoc wireless networks for supporting on-site communication and collaboration is proposed. Several modes of communication which are common in on-site applications are considered including location information, text messaging, voice and video communications, and file transmission. A prototype system is implemented for testing these modes based on available ad-hoc network protocols and using mobile devices. In addition, in order to verify our proposed approach, several tests are designed and implemented to demonstrate the usefulness of the prototype system. The results from the tests showed that our prototype system is applicable for ad-hoc wireless networks. Furthermore, a new protocol based on clustering to improve data accessibility in ad-hoc networks is tested using a simulation tool to study its performance under different scenarios. The simulation results showed the impact of the area size, wireless range, number of nodes, and node speed on data accessibility

    A quality of service architecture for WLAN-wired networks to enhance multimedia support

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    Includes abstract.Includes bibliographical references (leaves 77-84).The use of WLAN for the provision of IP multimedia services faces a number of challenges which include quality of service (QoS). Because WLAN users access multimedia services usually over a wired backbone, attention must be paid to QoS over the integrated WLAN-wired network. This research focuses on the provision of QoS to WLAN users accessing multimedia services over a wired backbone. In this thesis, the IEEE 802.11-2007 enhanced data channel access (EDCA) mechanism is used to provide prioritized QoS on the WLAN media access control (MAC) layer, while weighted round robin (WRR) queue scheduling is used to provide prioritized QoS at the IP layer. The inter-working of the EDCA scheme in the WLAN and the WRR scheduling scheme in the wired network provides end-to-end QoS on a WLAN-wired IP network. A mapping module is introduced to enable the inter-working of the EDCA and WRR mechanisms

    A Survey on Scheduling in IEEE 802.16 Mesh Mode

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    Cataloged from PDF version of article.IEEE 802.16 standard (also known as WiMAX) defines the wireless broadband network technology which aims to solve the so called last mile problem via providing high bandwidth Internet even to the rural areas for which the cable deployment is very costly. The standard mainly focuses on the MAC and PHY layer issues, supporting two transmission modes: PMP (Point-to-Multipoint) and mesh modes. Mesh mode is an optional mode developed as an extension to PMP mode and it has the advantage of having an improving performance as more subscribers are added to the system using multi-hop routes. In 802.16 MAC protocol, mesh mode slot allocation and reservation mechanisms are left open which makes this topic a hot research area. Hence, the focus of this survey will mostly be on the mesh mode, and the proposed scheduling algorithms and performance evaluation methods

    Escalonamento de pacotes áudio e vídeo em redes WiMAX em malha com QoS

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    Mestrado em Engenharia Electrónica e Telecomunicações´E evidente na actualidade que os utilizadores procuram cada vez mais aceder a servi¸cos multim´edia e aplica¸c˜oes interactivas nos seus terminais m´oveis. H´a, portanto, uma necessidade de implementar arquitecturas de Qualidadede- Servi¸co (QoS) e Qualidade-de-Experiˆencia (QoE) robustas, que sejam capazes de fornecer um atraso baixo para as aplica¸c˜oes interactivas, ao mesmo tempo que lidam com outro tipo de aplica¸c˜oes que requerem uma maior largura de banda, mas com mais tolerˆancia a atrasos, desta forma maximizando a utiliza¸c˜ao dos recursos dispon´ıveis na rede e melhorando a experiˆencia do utilizador final. A norma IEEE 802.16 representa uma das tecnologias mais avan¸cadas e de maior relevˆancia para o acesso sem fios em banda larga a redes de ´area metropolitana. O modo de opera¸c˜ao Ponto-multiponto (PMP) do IEEE 802.16 foi desenvolvido para suportar requisitos de QoS, control´avel pelo operador da rede, e desta forma complementando as solu¸c˜oes m´oveis de terceira-gera¸c˜ao j´a existentes. Um modo alternativo de opera¸c˜ao em malha (MESH) permite a cria¸c˜ao de redes flex´ıveis e auto-configur´aveis em que o tr´afego ´e encaminhado atrav´es de v´arios n´os. Esta tese aborda os temas de QoS e QoE quando aplicados a redes sem fios em malha, operando sobre a norma IEEE 802.16. S˜ao contribu´ıdos melhoramentos e an´alises de desempenho a uma nova arquitectura para trazer suporte de QoS ao modo de opera¸c˜ao MESH do standard 802.16. Tamb´em ´e apresentado um novo escalonador de pacotes com o objectivo de melhorar a qualidade subjectiva de servi¸cos de ´audio, v´ıdeo e transferˆencia de ficheiros que o utilizador final experiencia. Os resultados provenientes de simula¸c˜oes demonstram tanto a eficiˆencia da arquitectura QoS em termos de medidas objectivas como taxa de transfer ˆencia e atraso de pacotes, como o bom funcionamento do escalonador de pacotes para QoE, com melhorias vis´ıveis em m´etricas de qualidade subjectiva.It is clear nowadays that users are becoming increasingly interested in accessing multimedia and interactive applications on their mobile terminals. Therefore, there is a need to implement robust Quality-of-Service (QoS) and Quality-of-Experience (QoE) architectures capable of providing low delay for such interactive applications, while at the same time dealing with other bandwidth-hungry but more delay-tolerant services, and thereby maximizing the network’s available resources and improving the end-user experience. The IEEE 802.16 standard represents one of the most relevant and advanced technologies for broadband wireless access in metropolitan area networks. The point-to-multipoint (PMP) mode of IEEE 802.16 has been designed to support quality of service (QoS) requirements, controlled by the network operator, thus complementing the existing third-generation mobile solutions. An alternative mesh (MESH) mode of operation allows the creation of flexible, self-configuring networks with traffic routing through various nodes. This thesis approaches the subjects of QoS and QoE when applied to wireless mesh networks operating under the IEEE 802.16 standard. It provides improvements and performance evaluations of a new architecture to bring QoS support to the 802.16 MESH mode of operation. It also presents a new packet scheduler with the aim to improve the subjective quality of audio, video and file transfer services, as experienced by the end user. Simulation results demonstrate both the efficiency of the QoS architecture in terms of objective measurements such as throughput and packet delay, and the good functioning of the QoE-aware packet scheduler, with noticeable increases in subjective quality metrics

    Handover Architectures for Heterogeneous Networks Using the Media Independent Information Handover (MIH)

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    In heterogeneous networks, network selection by nature is a multi-dimensional problem. Many parameters need to be considered for handover decision making. Apart from handover accuracy and efficiency, an important consideration is the scalability and signaling overhead of such handover algorithms. In this article we propose to break down a Simple Additive Weighting (SAW) based heterogeneous handover algorithm in two parts. The execution of the first part is carried out in an independent and proactive manner prior to the actual handover, assuming three different handover architectures. The handover architectures are differentiated based upon the level of the distribution of the handover algorithm among multiple network components. The Media Independent Handover (MIH) and its different services are used to retrieve and share information among MIH enabled nodes and for conformity among heterogeneous network standards. The proposed algorithm is evaluated with respect to handover accuracy, handover delay efficiency and signaling overhead. The evaluation is carried out for all three handover architectures using simulations. Only handovers between Wi-Fi (IEEE 802.11) and WiMAX (IEEE 802.16) networks are considered. But the handover framework is general and can be extended to consider other wireless and mobile communication networks
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