On Improving Throughput via Cluster-based Flexible Channelization in Wireless LANs
| Autor: | Yu-Po Wang, 王裕博 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 With the increasing generality of the wireless network, various equipment which can surf the Internet and lots of place where we can use the wireless network both make surfing the Web become an easy thing. “Link Quality” is the most doubtful part for people when using the wireless network. If some delay phenomenon happened when using Internet, it not only lets people annoyed, but also eliminates their desire to use wireless network. There are a lot of researches about Link Quality when people started to use wireless network. This paper wants to discuss about “Flexible Channelization” which is used to solve the Link Quality problem in recent years. Using wider channel width can transmit more data and has smaller interference range; however, using narrower channel width can let receiver get stronger signal and occupies fewer space in spectrum. After knowing the property of various types of channel width, we want to know that what channel width and central frequency are used for each AP when transmitting data. According to existing researches, if APs which have interference relation with others use non-overlapping but smaller channels, the final throughput will be more than using overlapping but larger channels. In addition, differs with past researches which only focus on central frequency and channel width, we added the “Performance Anomaly” issue and re-discussed the association relation between APs and clients. When considering the “Performance Anomaly” issue, we hope the time of each client using the channel can be distributed for clients more fairly, and not letting the clients with slower rate degrade the total system throughput. In re-discussing the association between APs and clients part, because receiver will get different signal strength when APs using different channel width to transmit data, the traditional way which letting clients associated to the AP which provide strongest signal strength are not usable in flexible channel environment. Finally, considering all issues mentioned above, we design two algorithms: one for keeping time fairness for clients to maximize the system’s total throughput, the other for maximize the time fairness which clients using to receive data. We compare the simulation result of our works and past researches. No matter the whole system’s throughput and time fairness, we outperforms others, and it indicates that the algorithms which designed by considering all aspects mentioned above will increase the functionality of the whole system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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