861 research outputs found

    Performance Analysis of QoS in PMP Mode WiMax Networks

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    IEEE 802.16 standard supports two different topologies: point to multipoint (PMP) and Mesh. In this paper, a QoS mechanism for point to multipoint of IEEE 802.16 and BS scheduler for PMP Mode is proposed. This paper also describes quality of service over WiMAX networks. Average WiMAX delay, Average WiMAX load and Average WiMAX throughput at base station is analyzed and compared by applying different scheduler at Base station and at fixed nodes

    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

    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

    Multicast broadcast services support in OFDMA-based WiMAX systems [Advances in mobile multimedia]

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    Multimedia stream service provided by broadband wireless networks has emerged as an important technology and has attracted much attention. An all-IP network architecture with reliable high-throughput air interface makes orthogonal frequency division multiplexing access (OFDMA)-based mobile worldwide interoperability for microwave access (mobile WiMAX) a viable technology for wireless multimedia services, such as voice over IP (VoIP), mobile TV, and so on. One of the main features in a WiMAX MAC layer is that it can provide'differentiated services among different traffic categories with individual QoS requirements. In this article, we first give an overview of the key aspects of WiMAX and describe multimedia broadcast multicast service (MBMS) architecture of the 3GPP. Then, we propose a multicast and broadcast service (MBS) architecture for WiMAX that is based on MBMS. Moreover, we enhance the MBS architecture for mobile WiMAX to overcome the shortcoming of limited video broadcast performance over the baseline MBS model. We also give examples to demonstrate that the proposed architecture can support better mobility and offer higher power efficiency

    Connection admission control and packet scheduling for IEEE 802.16 networks

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    Includes bibliographical references.The IEEE 802.16 standard introduced as one of the Wireless Metropolitan Area Networks (WMAN) for Broadband Wireless Access (BWA) which is known as Worldwide Interoperability for Microwave Access (WiMAX), provides a solution of broadband connectivity to areas where wired infrastructure is economically and technically infeasible. Apart from the advantage of having high speeds and low costs, IEEE 802.16 has the capability to simultaneously support various service types with required QoS characteristics. ... While IEEE 802.16 standard defines medium access control (MAC) and physical (PHY) layers specification, admission control and packet scheduling mechanisms which are important elements of QoS provisioning are left to vendors to design and implement for service differentiation and QoS support

    Cross-layer RaCM design for vertically integrated wireless networks

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    Includes bibliographical references (p. 70-74).Wireless local and metropolitan area network (WLAN/WMAN) technologies, more specifically IEEE 802.11 (or wireless fidelity, WiFi) and IEEE 802.16 (or wireless interoperability for microwave access, WiMAX), are well-suited to enterprise networking since wireless offers the advantages of rapid deployment in places that are difficult to wire. However, these networking standards are relatively young with respect to their traditional mature high-speed low-latency fixed-line networking counterparts. It is more challenging for the network provider to supply the necessary quality of service (QoS) to support the variety of existing multimedia services over wireless technology. Wireless communication is also unreliable in nature, making the provisioning of agreed QoS even more challenging. Considering the advantages and disadvantages, wireless networks prove well-suited to connecting rural areas to the Internet or as a networking solution for areas that are difficult to wire. The focus of this study specifically pertains to IEEE 802.16 and the part it plays in an IEEE vertically integrated wireless Internet (WIN): IEEE 802.16 is a wireless broadband backhaul technology, capable of connecting local area networks (LANs), wireless or fixed-line, to the Internet via a high-speed fixed-line link
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