33 research outputs found

    Demonstration of wireless backhauling over long-reach PONs

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    An IEEE 802.16e-2005 (WiMAX) compliant, longreach passive optical network is demonstrated, focusing on the development of next generation optical access with transparent wireless backhauling. In addition to the extended feeder reach, a wavelength band overlay is used to enhance network scalability by maintaining passive splitting in the field and with some design modification at the optical line terminal and remote base station. Radio-over-fiber is used to minimize network installation and maintenance costs through the use of simple remote radio heads complemented by frequency division multiplexing to address individual base stations. The implementation of overlapping radio cells/sectors is also proposed to provide joint signal processing at wireless user terminals. Experimental measurements confirmed EVMs below -30 and -23 dB downstream and upstream, respectively, over fiber link lengths of up to 84.6 km. In addition, adjacent channel leakage ratio measurements demonstrated that a figure of -45 dB with 40 MHz subcarrier spacing, as specified by the standard, can be readily achieved.Peer reviewe

    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

    Hybrid Strategies for Link Adaptation Exploiting Several Degrees of Freedom in WiMAX Systems

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    Mobile WiMAX Performance Investigation

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    Although the Mobile-WiMAX technology is being deployed in the United States, Europe, Japan, Korea, Taiwan and in the Mideast, there are still ongoing discussions about the potential of this technology. What is really remarkable, in fact, with regard to the Mobile-WiMAX profile, is the high number of degrees of freedom that are left to manufacturers. The final decision on a lot of very basic and crucial aspects, such as, just to cite few of them, the bandwidth, the frame duration, the duplexing scheme and the up/downlink traffic asymmetry, are left to implementers. It follows that the performance of this technology is not clear yet, even to network operators. This consideration motivated our work, which is focused on the derivation of an analytical framework that, starting from system parameters and implementation choices, allows to evaluate the performance level provided by this technology, carefully taking all aspects of IEEE802.16e into account. In particular, the analysis starts from the choices to be made at the physical layer, among those admitted by the specification, and "goes up" through the protocol pillar to finally express the application layer throughput and the number of supported voice over IP (VoIP) users, carefully considering "along the way" all characteristics of the the medium access control (MAC) layer, the resource allocation strategies, the overhead introduced, the inherent inefficiencies, etc

    On MU-MIMO Precoding Techniques for WiMAX

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    A system level simulation study of WiMAX

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    Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2010.Thesis (Master's) -- Bilkent University, 2010.Includes bibliographical references leaves 56-58.In this thesis, we implement a WiMAX system level simulator compliant with the evaluation methodology document published by the IEEE 802.16m Task Group. We study the PHY abstraction of polar codes and integrate polar codes into the simulator. We compare the system level performances of polar code and convolutional turbo code (CTC) and observe that CTC outperforms polar code. On the simulator, we study the downlink (DL) performance of WiMAX under various configurations such as scheduling methods, subchannelization methods, and frequency reuse models. We study there types of scheduling methods, namely round robin (RR) scheduling, proportional fair (PF) scheduling, and maximum sum rate (MSR) scheduling. We observe that MSR scheduling has the best throughput performance but does not support the users far from the base station. We study three frequency reuse models, namely 1×3×1, 1×3×3, and 3×3×1. We observe that 1 ×3×1 reuse model has the best throughput performance and maximum spectral efficiency is obtained in 1 × 3 × 3 reuse model. We study two subchannelization methods, namely PUSC and band AMC. We observe that in low mobility cases, band AMC outperforms PUSC and in high mobility cases, PUSC is better than band AMC.Başçiftçi, Yüksel OzanM.S

    Review to the implementation of IPTV service over wireless and mobiles networks with Quality of Service (QoS)

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    In the Internet Protocol Television (IPTV) the quality of content delivered to users is affected by different parameters of network performance that must be secured at their minimum values to guarantee the quality perceived by users. The IPTV service deployment on wireless and mobile networks has been facing serious challenges due to limited bandwidth, low reliability and the quality of wireless communication links and user mobility. However, the latest broadband wireless technologies are emerging as suitable networks for the deployment of this service since they are all-IP architectures capabilities to provide end to-end Quality of Service (QoS) and increase the access speed. So, in this paper, we review the work that has been made for the IPTV implementation over wireless and mobile networks with QoS.En IPTV (Internet Protocol Television) la calidad de los contenidos entregados a los usuarios se ve afectada por diferentes parámetros de desempeño de la red que deben ser asegurados en sus valores mínimos para garantizar la calidad percibida por los usuarios. El despliegue del servicio de IPTV sobre redes inalámbricas y móviles ha enfrentado serios desafíos debido a las limitaciones de ancho de banda, a la baja fabilidad y calidad de los enlaces de comunicaciones inalámbricos y a la movilidad de los terminales. Sin embargo, las últimas tecnologías inalámbricas de banda ancha se perflan como redes idóneas para el despliegue de este servicio toda vez que son arquitecturas completamente IP (all-IP) con capacidades de ofrecer Calidad de Servicio (QoS, Quality of Service) de extremo a extremo e incrementan la velocidad de acceso. Por tanto, en este artículo se realiza la revisión de los trabajos que se han realizado para la implementación de la IPTV sobre redes inalámbricas y móviles con QoS
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