174,486 research outputs found

    Performance of sleep-mode mechanisms under light-traffic conditions

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    Modem standards for wireless telecommunication, such as IEEE 802. 16s (WiMAX"), foresee in several power-saving mechanisms. One of the main mechanisms is sleep-mode operation, which allows the mobile device to switch off the antenna during a negotiated time (it goes to sleep), thus reducing energy consumption. However, 1гаШс that arrives al the base station (BS) incurs an extra delay, because its delivery can only start after the sleep period has ended. The sleep-mode mechanism in WiMAX has provisions to vary the lengths of subsequent sleep periods, which allows to exploit correlation in the arriving traffic. We depart from our earlier analyses and study the mode! of the sleep-mode mechanists specifically under light-traffic conditions. This results in relatively short and simple formulas that give a lot of insight

    Wireless Standards and Mesh Networks.

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    On March 13th 1980, the Computer Society of the Institute of Electronics and Electrical Engineering (IEEE) approved project 802. IEEE 802 is led by the LAN/MAN Standards Committee(LMSC). Until today, 22 Working Groups (WGs) mainly define standards for the lowest two layers of the ISO/OSI reference model in the 802. For wireless communication, 802.11 WG defines the Wireless Local Area Network (WLAN), 802.15 WG defines the Wireless Personal Area Network (WPAN), and 802.16 WG defines the Wireless Metropolitan Area Network (WMAN) standard. With Multiple Input/Multiple Output (MIMO), Ultrawideband (UWB) and sensitive Modulation and Coding Schemes (MCSs), the latest developments in the IEEE 802 standards enable data rates beyond 500Mbps for new applications of wireless communication. Similar to preceding wireless technologies, data rate slows down by increase in distance of the communication entities. However, demands for new applications emerge that need high data rates regardless of distance. To overcome the link speed limitation, dense deployment of wireless networks is needed1. Wireless Mesh Networks (WMNs) help to overcome current dependencies of wireless communication systems on wired backbones by enabling cost-effective and rapid deployment for a new generation of wireless services

    The Building Standard (Scotland) Amendment Regulations 1964

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    ERAF: A6.SI.1964.802STATUTORY INSTRUMENTS 1964 No. 802 (S. 50) BUILDING AND BUILDINGS The Building Standards (Scotland) Amendment Regulations 196

    Adaptive Negotiation for Block Acknowledgment Session Management

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    International audienceThe expansion of wireless applications in dense environments raises many technical issues. The 802 standards need to adapt and enhance the network quality by developing new technologies. The block acknowledgment (BA) mechanism was introduced in the IEEE 802.11e standard to improve medium access control (MAC) efficiency. It requires the exchange of many control frames to establish a session with each user, which turns into an issue for networks in dense environments as it causes increased overhead and latency. This paper deals with the optimization of the BA session management procedure. We propose a modified block acknowledgment session control mechanism which reduces the overhead and latency compared to the original one

    The history of WiMAX: a complete survey of the evolution in certification and standarization for IEEE 802.16 and WiMAX

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    Most researchers are familiar with the technical features of WiMAX technology but the evolution that WiMAX went through, in terms of standardization and certification, is missing and unknown to most people. Knowledge of this historical process would however aid to understand how WiMAX has become the widespread technology that it is today. Furthermore, it would give insight in the steps to undertake for anyone aiming at introducing a new wireless technology on a worldwide scale. Therefore, this article presents a survey on all relevant activities that took place within three important organizations: the 802.16 Working Group of the IEEE (Institute of Electrical and Electronics Engineers) for technology development and standardization, the WiMAX Forum for product certification and the ITU (International Telecommunication Union) for international recognition. An elaborated and comprehensive overview of all those activities is given, which reveals the importance of the willingness to innovate and to continuously incorporate new ideas in the IEEE standardization process and the importance of the WiMAX Forum certification label granting process to ensure interoperability. We also emphasize the steps that were taken in cooperating with the ITU to improve the international esteem of the technology. Finally, a WiMAX trend analysis is made. We showed how industry interest has fluctuated over time and quantified the evolution in WiMAX product certification and deployments. It is shown that most interest went to the 2.5 GHz and 3.5GHz frequencies, that most deployments are in geographic regions with a lot of developing countries and that the highest people coverage is achieved in Asia Pacific. This elaborated description of all standardization and certification activities, from the very start up to now, will make the reader comprehend how past and future steps are taken in the development process of new WiMAX features

    Performance improvements to the 802.11 wireless network medium access control sub-layer : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Computer Systems Engineering at Massey University

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    This thesis presents the outcome into the research and development of improvements to the 802.11 wireless networking medium access control (MAC) sublayer. The main products of the research are three types of improvement that increase the efficiency and throughput of the 802.11 protocol. Beginning with an overview of the original 802.11 physical layer and MAC sub-layer standard, the introductory chapters then cover the many supplements to the original standard (including a brief on the future 802.11n supplement). The current state of the 802.11 MAC sub-layer is presented along with an assessment of the realistic performance available from 802.11. Lastly, the motivations for improving the MAC sub-layer are explained along with a summary of existing research into this area. The main improvement presented within the thesis is that of packet aggregation. The operation of aggregation is explained in detail, along with the reasons for the significant available throughput increase to 802.11 from aggregation. Aggregation is then developed to produce even higher throughput, and to be a more robust mechanism. Additionally, aggregation is formally described in the form of an update to the existing 802.11 standard. Following this, two more improvements are shown that can be used either with or without the aggregation mechanism. Stored frame headers are designed to reduce repetition of control data, and combined acknowledgements are an expansion of the block acknowledgement system introduced in the 802.11e supplement. This is followed by a description of the simulation environment used to test the three improvements presented, such as the settings used and metrics created. The results of the simulations of the improvements are presented along with the discussion. The developments to the basic improvements are also simulated and discussed in the same way. Finally, conclusions about the improvements detailed and the results shown in the simulations are drawn. Also at the end of the thesis, the possible future direction of research into the improvements is given, as well as the aspects and issues of implementing aggregation on a personal computer based platform

    Broadband Center of Excellence Newsletter, May 2016

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    Broadband Center of Excellence Newsletter, October 2017

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    Broadband Center of Excellence Newsletter, August 2016

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