An Optimization-Based Algorithm for Mitigation of Starvation in IEEE 802.11 Wireless Networks
| Autor: | Shi-Yao Chen, 陳仕堯 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Distributed Coordination Function (DCF) is a fundamental MAC mechanism of the IEEE 802.11 based WLAN standard to access the medium and reduce possibility of collisions by Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). Each flow of sender must check whether the medium is available or not before sending data. However, in some situations, the random access protocol, CSMA/CA, cause serious unfairness or flow starvation. In this research, we focus on mitigating starvation problems in Wi-Fi ad hoc networks for improving the wireless network service. Adapting the transmission power range, carrier sense threshold are used in the work. The objective is to alleviate the starvation problems between nodes in the densely wireless network. In this thesis, we model the optimal mathematical formulation for describing and mitigating the starvation problems with objective function and some constraints. To fast solve the mathematical optimization, we utilize an approach, Lagrangean Relaxation (LR), which approximates another problem of constrained optimization by a similar problem. The feasible solution is derived from information provided by the Lagrangean multipliers. We are going to use Visual Studio 2013 and C/C++ for computational experiments which some scenarios are designed for evaluating the starvation problems. We anticipate that the expectation results with LR-based approach will be within the twenty-percent gap to the real optimum. Finally, we will get the result which minimizes the starvation problems in IEEE 802.11 wireless networks. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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