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| Author(s): |
Luciano Jerez Chaves
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Computação |
| Defense date: | 2010-11-06 |
| Examining board members: |
Edmundo Roberto Mauro Madeira;
Luis Henrique Maciel Kosmalski Costa;
Nelson Luis Saldanha da Fonseca
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| Advisor: | Edmundo Roberto Mauro Madeira; Islene Calciolari Garcia |
| Abstract | |
Wireless networks have become frequently used nowadays, and IEEE 802.11 is the standard chosen for practically all devices. Aiming to adapt to changing conditions of wireless channels, this standard specifies several modulation and coding schemes that must be implemented by all wireless interfaces. As a result, these interfaces can support multiple data rates, which are named according to the selected modulation and coding schemes. However, this standard does not define how to dynamically select the transmission rate to be used, allowing manufacturers to create and implement their own algorithm to solve this problem, known as the rate adaptation problem. Despite that several solutions have been proposed in the literature, the performance achieved by them is limited by factors such as the difficulty in estimating wireless channel conditions and unfair resource sharing among network nodes. In order to tackle these challenges, this work introduces a cognitive mechanism for rate adaptation called CORA. This is a completely distributed mechanism, capable of equipping network stations with self-configuration functionality to dynamically adapt the data rate. This mechanism is also able to quickly react to changes on channel conditions in order to avoid performance degradation, and can converge to the best data rate during periods of stability. To do this, CORA makes use of a simplistic approach for assessing the channel conditions, besides presenting specific features that may ensure fair resource sharing among nodes. The proposed mechanism is evaluated by simulations, and the results are compared with some solutions existing in the literature and also with algorithms that are used in commercial devices. Simulation results confirm performance benefits with respect to the other rate adaptation algorithms evaluated (AU) | |
| FAPESP's process: | 08/07770-8 - Autonomic Resource Management in Wireless Mesh Networks |
| Grantee: | Luciano Jerez Chaves |
| Support Opportunities: | Scholarships in Brazil - Master |