Spelling suggestions: "subject:"lifetime maximization"" "subject:"iifetime maximization""
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Energy-efficient relay cooperation for lifetime maximizationZuo, Fangzhi 01 August 2011 (has links)
We study energy-efficient power allocation among relays for lifetime maximization
in a dual-hop relay network operated by amplify-and-forward relays with battery
limitations. Power allocation algorithms are proposed for three different scenarios.
First, we study the relay cooperation case where all the relays jointly support
transmissions for a targeted data rate. By exploring the correlation of time-varying
relay channels, we develop a prediction-based relay cooperation method for optimal
power allocation strategy to improve the relay network lifetime over existing methods
that do not predict the future channel state, or assume the current channel state
remains static in the future.
Next, we consider energy-efficient relay selection for the single source-destination
case. Assuming finite transmission power levels, we propose a stochastic shortest path
approach which gives the optimal relay selection decision to maximize the network
lifetime. Due to the high computational complexity, a suboptimal prediction-based
relay selection algorithm, directly coming from previous problem, is created.
Finally, we extend our study to multiple source-destination case, where relay selection
needs to be determined for each source-destination pair simultaneously. The
network lifetime in the presence of multiple source-destination pairs is defined as the
longest time when all source-destination pairs can maintain the target transmission
rate. We design relay-to-destination mapping algorithms to prolong the network lifeii
time. They all aim at maximizing the perceived network lifetime at the current time
slot. The optimal max-min approach and suboptimal user-priority based approach
are proposed with different levels of computational complexity. / UOIT
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Reproducibility and Applicability of a Fuzzy-based Routing Algorithm in Wireless Sensor NetworksRönningen, Hannes, Olofsson, Erik January 2023 (has links)
Wireless sensor networks is a broad subject with many applications and interesting research areas, such as optimization within connectivity and energy efficiency. One problem is that most published articles in this field use customized simulation environments and do not provide source code of their implementation. By not including aspects of implementation, it becomes difficult to determine how the results are achieved, which questions the validity and reliability of the works. This thesis aims to reproduce one of these researched methods, an algorithm that balances battery life with efficient routing within a network using fuzzy logic, with the goal to increase the reliability of the methodology within its field. The research question constructed on the foundation of these premises is thus “Is reproducibility satisfactory in a research work on a multi-objective routing algorithm, using fuzzy logic, in wireless sensor networks?, a case study by Minhas et al”. Two additional research questions emerge from the first one: “How does the reproduced algorithm perform in comparison to a selection of dif erent routing algorithms?” and “Is the reproduced algorithm, as is, applicable to a less idealistic environment?” To answer the research questions a computer simulation method is used to build, execute, and analyze the output of the algorithms. The results show that the implemented algorithm performs noticeably better in both lifetime and ratio to the shortest path compared with the original implementation, hinting towards the implementation and reproducibility deviating from expected results. The reproduced algorithm is also compared to two other algorithms under a different simulation environment, where it performs better in lifetime and packet delivery rate whilst performing slightly worse in energy efficiency and total energy consumption. Due to the significant differences in performance against the reproduced article’s implementation the study concludes that the reproducibility is not satisfactory. Lastly, it concludes that it does not perform well in a less idealistic simulation environment, making it less applicable.
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