667 research outputs found

    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

    WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches

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    WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations

    Joint Concurrent Routing and Multi-Pointer Packet Scheduling in IEEE 802.16 Mesh Networks

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    IEEE 802.16, also known as Worldwide Interoperability for Microwave Access (WiMAX), is a standardization effort carried out by the IEEE to provide last-mile broadband access to end users. The IEEE 802.16 standard supports two medium access control (MAC) modes - a mandatory point to multipoint (PMP) mode and an optional mesh mode. In this paper, we propose an asymmetric interference aware routing algorithm and a new multipointer approach in implementing scheduling algorithms for IEEE 802.16 mesh networks. We modify three different centralized scheduling algorithms, fixed scheduling, ordered scheduling and per-slot scheduling using multipointer approach to allow for spatial reuse (SR) in IEEE 802.16 mesh networks. Simulation results reveal that fixed scheduling with SR provides the best performance

    WiMAX Basics From Deployments to PHY Improvements

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    © ASEE 2014WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations

    Performance analysis of contention based bandwidth request mechanisms in WiMAX networks

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    This article is posted here with the permission of IEEE. The official version can be obtained from the DOI below - Copyright @ 2010 IEEEWiMAX networks have received wide attention as they support high data rate access and amazing ubiquitous connectivity with great quality-of-service (QoS) capabilities. In order to support QoS, bandwidth request (BW-REQ) mechanisms are suggested in the WiMAX standard for resource reservation, in which subscriber stations send BW-REQs to a base station which can grant or reject the requests according to the available radio resources. In this paper we propose a new analytical model for the performance analysis of various contention based bandwidth request mechanisms, including grouping and no-grouping schemes, as suggested in the WiMAX standard. Our analytical model covers both unsaturated and saturated traffic load conditions in both error-free and error-prone wireless channels. The accuracy of this model is verified by various simulation results. Our results show that the grouping mechanism outperforms the no-grouping mechanism when the system load is high, but it is not preferable when the system load is light. The channel noise degrades the performance of both throughput and delay.This work was supported by the U.K. Engineering and Physical Sciences Research Council (EPSRC) under Grant EP/G070350/1 and by the Brunel University’s BRIEF Award

    A Novel QoS Guarantee Mechanism in IEEE 802.16 Mesh Networks

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    IEEE 802.16 defines perfect QoS (Quality of Service) guarantee mechanism in PMP (Point to Multi-Point) mode and denotes mesh mode cannot provide this capability. To resolve this problem of WiMAX Mesh network, a novel QoS guarantee mechanism including protocol process and minislot allocation algorithm is proposed. This mechanism uses existing service classes in original standard. Protocol processes that manage dynamic service flow are defined. WiMAX MAC layer is re-designed to support service classification in mesh mode. Using extended distributed scheduling messages, the delivery method of dynamic service management messages in WiMAX mesh networks is implemented. Minislot allocation algorithm is given to support data scheduling of various services. Service establishment time is analyzed in this paper. The simulation result shows that the mechanism can provide QoS in WiMAX mesh networks effectively

    Study of IEEE802.16e standards to improve QoS throughput and delay analysis of PMP MAC Scheduling algorithms

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    WiMAX has two modes of operation: Point to Multi Point (PMP) mode and Mesh mode. PMP mode consists of one BS and multiple SS.The Wi-MAX is IEEE 802.16 Wireless network standard which recently used for Broadband Wireless communication. Now days to satisfy the highest demand of broadband wireless access by using various resource of bandwidth is a biggest challenge for Researchers, in this time WiMAX (Worldwide Interoperability for Microwave Access) emerged as a better solution to fulfil that demand. To provide authentic services for voice, data and videos WiMAX define the various QoS parameters at Media Access Control (MAC) layer. WiMAX structure is based on IEEE 802.16 OSI standard and defines the PMP (Point to Multipoint) and Mesh modes for transmission of information. In this study, cross-layer scheduling algorithm for Wimax networks has been proposed
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