Efficiency and Fairness Improvement Using Dynamic Adaptive EDCA for IEEE 802.11 Ad-hoc networks
| Autor: | Wen-Shen Wang, 王文聖 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 The proposed method is trying to change the process of Content Window (CW) when frames is suffered colliding which are working in Enhanced Distributed Channel Access (EDCA), called Dynamic Adaptive EDCA (DAEDCA). According to IEEE 802.11e, the EDCA mechanism defines four access categories (ACs) that provide support for the delivery of traffic with eight Ups from 802.1d at the STATIONs. EDCA considers two basic priority mechanisms for accessing the channel: different per-class setting of the CW back off parameters (CWmin and CWmax), and different per-class setting of the idle time after which a transmission may occur (arbitration inter-frame space, AIFS) to make sure successfully support QoS. Each AC within the station behaves like a virtual station: it contends for access to the medium and independently starts its back off time after sensing if the medium is idle for at least AIFS. After unsuccessful transmission, the frame will go into back off procedure to recalculate its CW. This solution will waste the interval till next frame’s back off counter count down to zero, and not guarantee low priority frame’s transmission. The proposed method modified the procedure and successfully improved performance on wireless frame accessing, and decreased the collision rate, and make sure to give low priority AC more service and even not affect time-delay bound performance. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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