A Survey on Scheduling in IEEE 802.16 Mesh Mode

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

Resource allocation in WiMAX mesh networks

ix, 77 leaves : ill. ; 29 cmThe IEEE 802.16 standard popularly known as WiMAX is at the forefront of the technological drive. Achieving high system throughput in these networks is challenging due to interference which limits concurrent transmissions. In this thesis, we study routing and link scheduling inWiMAX mesh networks. We present simple joint routing and link scheduling algorithms that have outperformed most of the existing proposals in our experiments. Our session based routing and links scheduling produced results approximately 90% of a trivial lower bound. We also study the problem of quality of service (QoS) provisioning in WiMAX mesh networks. QoS has become an attractive area of study driven by the increasing demand for multimedia content delivered wirelessly. To accommodate the different applications, the IEEE 802.16 standard defines four classes of service. In this dissertation, we propose a comprehensive scheme consisting of routing, link scheduling, call admission control (CAC) and channel assignment that considers all classes of service. Much of the work in the literature considers each of these problems in isolation. Our routing schemes use a metric that combines interference and traffic load to compute routes for requests while our link scheduling ensures that the QoS requirements of admitted requests are strictly met. Results from our simulation indicate that our routing and link scheduling schemes significantly improve network performance when the network is congested

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

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

Dynamic Adaptation of the Distributed Election Procedure in IEEE 802.16 WMNs

The goal is to propose an algorithm wich gives to every node of the mesh network the possibility to adapt the holdoff time dynamically and than evaluate the performance

Qualidade de serviço em redes IEEE 802.16 com topologia em malha

Mestrado em Engenharia Electrónica e TelecomunicaçõesO 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 início com suporte para qualidade de serviço (QoS) gerida pelo controlador ou operador da rede, podendo assim complementar, as actuais soluções móveis de terceira geração. Por outro lado, a topologia opcional “em malha” (Mesh) permite a criação de redes autoconfiguráveis e com encaminhamento de tráfego através de vários pontos da rede. No entanto, as especificações e mecanismos de QoS apresentados na norma não são 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 coexistência dos dois modos de operação. A arquitectura apresentada foca-se numa gestão eficiente da largura de banda utilizando mensagens de controlo ao nível MAC introduzidas pelo standard IEEE 802.16. Os resultados obtidos mostram a eficiência 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

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

Advanced Protocols for Peer-to-Peer Data Transmission in Wireless Gigabit Networks

This thesis tackles problems on IEEE 802.11 MAC layer, network layer and application layer, to further push the performance of wireless P2P applications in a holistic way. It contributes to the better understanding and utilization of two major IEEE 802.11 MAC features, frame aggregation and block acknowledgement, to the design and implementation of opportunistic networks on off-the-shelf hardware and proposes a document exchange protocol, including document recommendation. First, this thesis contributes a measurement study of the A-MPDU frame aggregation behavior of IEEE 802.11n in a real-world, multi-hop, indoor mesh testbed. Furthermore, this thesis presents MPDU payload adaptation (MPA) to utilize A-MPDU subframes to increase the overall throughput under bad channel conditions. MPA adapts the size of MAC protocol data units to channel conditions, to increase the throughput and lower the delay in error-prone channels. The results suggest that under erroneous conditions throughput can be maximized by limiting the MPDU size. As second major contribution, this thesis introduces Neighborhood-aware OPPortunistic networking on Smartphones (NOPPoS). NOPPoS creates an opportunistic, pocket-switched network using current generation, off-the-shelf mobile devices. As main novel feature, NOPPoS is highly responsive to node mobility due to periodic, low-energy scans of its environment, using Bluetooth Low Energy advertisements. The last major contribution is the Neighborhood Document Sharing (NDS) protocol. NDS enables users to discover and retrieve arbitrary documents shared by other users in their proximity, i.e. in the communication range of their IEEE 802.11 interface. However, IEEE 802.11 connections are only used on-demand during file transfers and indexing of files in the proximity of the user. Simulations show that NDS interconnects over 90 \% of all devices in communication range. Finally, NDS is extended by the content recommendation system User Preference-based Probability Spreading (UPPS), a graph-based approach. It integrates user-item scoring into a graph-based tag-aware item recommender system. UPPS utilizes novel formulas for affinity and similarity scoring, taking into account user-item preference in the mass diffusion of the recommender system. The presented results show that UPPS is a significant improvement to previous approaches

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

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