Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"coordination function"”.
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Enhanced Collision Resolution for the IEEE 802.11 Distributed Coordination Function
… IEEE 802.11 standard relies on the Distributed Coordination Function (DCF) as the fundamental medium access control method. DCF uses the Binary Exponential Backoff (BEB) algorithm to regulate channel access. The backoff period determined by BEB depends on a contention window (CW) whose size is …
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Performance analysis of relay based cooperative MAC protocols
… we propose an Enhanced relay-enabled Distributed Coordination Function (ErDCF), which uses high data rate nodes to work as relays for the low data rate nodes. ErDCF in saturation achieves higher throughput, lower delay and lower energy consumption as compared to conventional 802.11 Distributed …
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Performance of voice and data transmission using the IEEE 802.11 MAC Protocol
… (CSMA/CA) protocol called the Distributed Coordination Function (DCF). The MAC protocol also includes an optional polling scheme called the Point Coordination Function (PCF) to deliver near-isochronous service to stations. This thesis analyzes the performance of these two medium access …
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A new localized approach to distributed fair scheduling in multihop wireless networks
… time fair queuing (STFQ) into the Distributed Coordination Function (DCF) in IEEE 802.11. Our algorithm accounts for the services, that have already been received by the sender, to adjust the backoff timer, so that every flow can get fair service. We propose a simple data structure that every …
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A hardware testbed for measuring IEEE 802.11g DCF performance
The Distributed Coordination Function (DCF) is the oldest and most widely-used IEEE 802.11 contention-based channel access control protocol. DCF adds a significant amount of overhead in the form of preambles, frame headers, randomised binary exponential back-off and inter-frame spaces. Having …
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Design of Media Access Control Schemes for Performance Enhancement of Future Generation Wireless Systems
… to share the wireless resource. The distributed coordination function (DCF) is the most commonly used multiple access scheme in WLANs and a member of the 802.11 standard [1]. In this thesis, two major roles of MAC protocols are examined: maximizing network throughput and service differentiation. …
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Analysing health systems responses to forced migration through the complementary lenses of resilience and responsiveness
… best practices and lack of a dedicated coordination function for ASR health has hampered a resilient response. Locally, several initiatives have demonstrated how resilience capacities may be strengthened through the increased involvement of public health offices in ASR health. Improved …
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Cross-layer optimizations in multi-hop ad hoc networks
… the clustering scheme could support MAC layer coordination among nodes, by shifting the distributed MAC paradigm towards a pseudo-centralized MAC paradigm. On the other hand, the system benefits of the clustering scheme could be emphasized by the pseudo-centralized MAC layer with the support …
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Addressing the hidden terminal problem in MU-MIMO WLANs with relaxed zero-forcing approach
… developed which is backed by an extended Point Coordination Function (PCF), d) an explicit channel acquisition framework is proposed for ZF which has a reduced signaling time overhead of 98.6740 μs compared to IEEE802.11ac. e) performance evaluation methodologies are: i) hardware testbed results …
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Performance modelling and enhancement of wireless communication protocols
… procedures of the IEEE 802.11 Distributed Coordination Function (DCF) protocol and suggests certain protocol enhancements aiming at maximising performance. A new, elegant and accurate analysis based on Markov chain modelling is developed for the idealistic assumption of unlimited packet …
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On Wireless Local Area Networks
… deals with analytical models for the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, while the second part (Chapters 5 and 6) focuses on the transmission rates provided by the IEEE 802.11 PHY layer. Analytical models are widely adopted in research into WLANs, especially IEEE 802.11 …
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Design of MAC protocols to support quality of service for multimedia traffic in wireless LANs
… research. The first is the Segregation Hybrid Coordination Function (SHCF) MAC protocol. This protocol is based on traffic segregation, where real-time traffic is segregated from non real-time traffic. This enables the real-time traffic to avoid competition from the non real-time traffic to …
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Human Interfaces for Cooperative Control of Multiple Vehicle Systems
… arrival, and loose sequential arrival. Coordination variables and functions are the strategy by which both temporal and spatial information is used to achieve cooperative timing at a minimum cost. Specifically, coordination variables and functions are used to plan trajectories for a team …