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Title | IEEE 802.16網狀網路環境中降低媒體存取延遲研究 Delay Reduction of Media Access for IEEE 802.16 Mesh Network |
Creator | 林暐清 Lin, Wei Ching |
Contributor | 張宏慶 Jang, Hung Chin 林暐清 Lin, Wei Ching |
Key Words | 網狀網路 降低延遲 媒體允入 WiMAX mesh network holdoff delay reduction media access IEEE 802.16 |
Date | 2007 |
Date Issued | 8-Dec-2010 11:59:16 (UTC+8) |
Summary | 本研究在減低Wimax mesh mode環境中media access階段會造成的delay現象。我們發現當subscriber station (SS)訊務繁忙時,競爭transmission opportunity (TO)以及3-way handshake的過程容易失敗,造成傳輸效率降低,封包的delay也會增加。同時我們也發現封包的延遲還來自minislot的不良配置。因為原始的Wimax mesh mode對於minislot的配置會造成預約過晚的問題,當預約時間被延長,資料就必須無條件的增加等待時間,因此我們將針對這些問題進行改善,降低在訊務繁忙的狀況下,傳輸效率低落的問題。 我們使用兩種方式來改善上述的問題,其一是由Bayer [4]所提出的動態調整holdoff指數(dynamic holdoff exponent)的方式,藉由調整holdoff指數的大小來縮短holdoff時間,以縮短傳輸延遲;另外,我們也提出一個以節點的臨接區域為配置基準(Neighborhood-Based Minislot Allocation, NBMA) 的方法,透過與其相鄰的節點交換訊息,優化minislot的配置。我們用這兩種方式減少IEEE 802.16中媒體存取階段所造成的傳輸延遲。 實驗結果顯示,在網路負載較輕的情況下,NBMA可以有效的將delay降低為原來的七分之一,改善幅度將近85%,抖動率(jitter)的部分亦有20%的改善,並略為提高傳輸效能8%左右;而當網路負載較重時,delay的改善程度仍有40%左右,jitter部分改善了12%,傳輸效能亦有6%的改善。證明了我們的方法確實可行,並且在改善delay方面有顯著的效果。 IEEE 802.16 mesh network is a new environment of wireless network. It was designed as a self-organized, distributed scheduling, and multi-hop network. However, it is not robust enough to handle a heavy loading environment for lacking of QoS support. Our research is trying to reduce its media access delay, which comes from both TO (transmission opportunity) competition and improper minislot allocation. TO competition will extend the MSH-DSCH (mesh distributed scheduling) interval and slow down the exchanging speed of control message. Improper minislot allocation comes from the distributed scheduling of minislot. When a subscriber station (SS) allocates too much minislot for low-level traffic, it will defer the allocation of other neighbors’ high-level traffic. We use Bayer’s [4] dynamic exponent to reduce holdoff time of SS, and speed up the exchange of control message. On the other hand, we design an “importance factor” (IM-factor) to score the importance of request. Through the exchange of IM-factor, SS and its neighbors will produce a threshold of IM-factor to filter the unimportant requests, and prevent minislot from being assigned too late. In our experiments, the proposed methods can reduce 85% delay and 20% jitter, and increase bandwidth utility by 7%. It shows that our method in reducing transmission delay is pratical and effective. |
參考文獻 | [1] IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems, IEEE Std 802.16-2004. IEEE, 2004. [2] M. Cao, W. Ma, Q. Zhang, and X. Wang, “Analysis of IEEE 802.16 Mesh Mode Scheduler Performance” IEEE Transaction on Wireless Communication, Vol. 6, NO. 4, April 2007. [3] M. Cao, W. Ma, Q. Zhang, and X. Wang, “Modeling and Performance Analysis of the Distributed Scheduler in IEEE 802.16 Mesh Mode” Proc. ACM MobiHoc ’05, May 2005, pp.78-89. [4] N. Bayer, B. Xu, V. Rakocevic, and J. Habermann, “Improving the Performance of the distributed Scheduler in IEEE 802.16 Mesh Networks”, Proceedings of Vehicular Technology Conference (IEEE VTC), Dublin, Ireland, April 2007. [5] N. Bayer, B. Xu, V. Rakocevic, and J. Habermann, “Transmission Timing of Messages in IEEE 802.16 based Mesh Networks”, Proceedings of IEEE/VDE European Wireless, Athens, Greece, April, 2006. [6] M.S. Kuran, B. Yilmaz, F. Alagoz, and T. Tugcu, “Quality of service in mesh mode IEEE 802.16 networks”, 14th International Conference on Software, Telecommunications and Computer Networks 2006, (SoftCOM `06), Split-Dubrovnik, Croatia, 2006, pp. 107-111. [7] K. Wongthavarawat, and A. Ganz, “Packet Scheduling for QoS support in IEEE 802.16 broadband wireless access systems”, Int. J. Commun. Syst. Vol. 16, Issue 1, pp: 81--96, 2003. [8] S.Y. Wang, C.L. Chou, C.H. Huang, C.C. Hwang, Z.M. Yang, C.C. Chiou, and C.C. Lin, "The Design and Implementation of the NCTUns 1.0 Network Simulator," Computer Networks, Vol. 42, Issue 2, June 2003, pp.175-197. |
Description | 碩士 國立政治大學 資訊科學學系 94753022 96 |
資料來源 | http://thesis.lib.nccu.edu.tw/record/#G0094753022 |
Type | thesis |
dc.contributor.advisor | 張宏慶 | zh_TW |
dc.contributor.advisor | Jang, Hung Chin | en_US |
dc.contributor.author (Authors) | 林暐清 | zh_TW |
dc.contributor.author (Authors) | Lin, Wei Ching | en_US |
dc.creator (作者) | 林暐清 | zh_TW |
dc.creator (作者) | Lin, Wei Ching | en_US |
dc.date (日期) | 2007 | en_US |
dc.date.accessioned | 8-Dec-2010 11:59:16 (UTC+8) | - |
dc.date.available | 8-Dec-2010 11:59:16 (UTC+8) | - |
dc.date.issued (上傳時間) | 8-Dec-2010 11:59:16 (UTC+8) | - |
dc.identifier (Other Identifiers) | G0094753022 | en_US |
dc.identifier.uri (URI) | http://nccur.lib.nccu.edu.tw/handle/140.119/49465 | - |
dc.description (描述) | 碩士 | zh_TW |
dc.description (描述) | 國立政治大學 | zh_TW |
dc.description (描述) | 資訊科學學系 | zh_TW |
dc.description (描述) | 94753022 | zh_TW |
dc.description (描述) | 96 | zh_TW |
dc.description.abstract (摘要) | 本研究在減低Wimax mesh mode環境中media access階段會造成的delay現象。我們發現當subscriber station (SS)訊務繁忙時,競爭transmission opportunity (TO)以及3-way handshake的過程容易失敗,造成傳輸效率降低,封包的delay也會增加。同時我們也發現封包的延遲還來自minislot的不良配置。因為原始的Wimax mesh mode對於minislot的配置會造成預約過晚的問題,當預約時間被延長,資料就必須無條件的增加等待時間,因此我們將針對這些問題進行改善,降低在訊務繁忙的狀況下,傳輸效率低落的問題。 我們使用兩種方式來改善上述的問題,其一是由Bayer [4]所提出的動態調整holdoff指數(dynamic holdoff exponent)的方式,藉由調整holdoff指數的大小來縮短holdoff時間,以縮短傳輸延遲;另外,我們也提出一個以節點的臨接區域為配置基準(Neighborhood-Based Minislot Allocation, NBMA) 的方法,透過與其相鄰的節點交換訊息,優化minislot的配置。我們用這兩種方式減少IEEE 802.16中媒體存取階段所造成的傳輸延遲。 實驗結果顯示,在網路負載較輕的情況下,NBMA可以有效的將delay降低為原來的七分之一,改善幅度將近85%,抖動率(jitter)的部分亦有20%的改善,並略為提高傳輸效能8%左右;而當網路負載較重時,delay的改善程度仍有40%左右,jitter部分改善了12%,傳輸效能亦有6%的改善。證明了我們的方法確實可行,並且在改善delay方面有顯著的效果。 | zh_TW |
dc.description.abstract (摘要) | IEEE 802.16 mesh network is a new environment of wireless network. It was designed as a self-organized, distributed scheduling, and multi-hop network. However, it is not robust enough to handle a heavy loading environment for lacking of QoS support. Our research is trying to reduce its media access delay, which comes from both TO (transmission opportunity) competition and improper minislot allocation. TO competition will extend the MSH-DSCH (mesh distributed scheduling) interval and slow down the exchanging speed of control message. Improper minislot allocation comes from the distributed scheduling of minislot. When a subscriber station (SS) allocates too much minislot for low-level traffic, it will defer the allocation of other neighbors’ high-level traffic. We use Bayer’s [4] dynamic exponent to reduce holdoff time of SS, and speed up the exchange of control message. On the other hand, we design an “importance factor” (IM-factor) to score the importance of request. Through the exchange of IM-factor, SS and its neighbors will produce a threshold of IM-factor to filter the unimportant requests, and prevent minislot from being assigned too late. In our experiments, the proposed methods can reduce 85% delay and 20% jitter, and increase bandwidth utility by 7%. It shows that our method in reducing transmission delay is pratical and effective. | en_US |
dc.description.tableofcontents | 第一章 緒論 8 1.1簡介 8 1.2研究動機與目的 10 1.3 IEEE 802.16的分散排程 11 1.3.1 Competition of Transmission Opportunity 12 1.3.2 Mesh mode signal 16 1.3.3 3-way handshake 18 第二章 相關研究 21 第三章 研究方法 25 3.1 問題描述 25 3.1.1 TO Interval 25 3.1.2 Minislot allocation 26 3.2 研究方法與原因 29 3.3 研究進行步驟 33 3.3.1 Delay-Sensitive Request and Virtual Node 34 3.3.2 Dynamic Holdoff Exponent 36 3.3.3 Request Scoring 39 3.3.4 Neighborhood distribution 49 第四章 模擬實驗 51 4.1 模擬環境 51 4.2 模擬實驗一 52 4.3 模擬實驗二 56 第五章 結論與未來研究 63 第六章 參考文獻 64 | zh_TW |
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dc.language.iso | en_US | - |
dc.source.uri (資料來源) | http://thesis.lib.nccu.edu.tw/record/#G0094753022 | en_US |
dc.subject (關鍵詞) | 網狀網路 | zh_TW |
dc.subject (關鍵詞) | 降低延遲 | zh_TW |
dc.subject (關鍵詞) | 媒體允入 | zh_TW |
dc.subject (關鍵詞) | WiMAX | en_US |
dc.subject (關鍵詞) | mesh network | en_US |
dc.subject (關鍵詞) | holdoff | en_US |
dc.subject (關鍵詞) | delay reduction | en_US |
dc.subject (關鍵詞) | media access | en_US |
dc.subject (關鍵詞) | IEEE 802.16 | en_US |
dc.title (題名) | IEEE 802.16網狀網路環境中降低媒體存取延遲研究 | zh_TW |
dc.title (題名) | Delay Reduction of Media Access for IEEE 802.16 Mesh Network | en_US |
dc.type (資料類型) | thesis | en |
dc.relation.reference (參考文獻) | [1] IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems, IEEE Std 802.16-2004. IEEE, 2004. | zh_TW |
dc.relation.reference (參考文獻) | [2] M. Cao, W. Ma, Q. Zhang, and X. Wang, “Analysis of IEEE 802.16 Mesh Mode Scheduler Performance” IEEE Transaction on Wireless Communication, Vol. 6, NO. 4, April 2007. | zh_TW |
dc.relation.reference (參考文獻) | [3] M. Cao, W. Ma, Q. Zhang, and X. Wang, “Modeling and Performance Analysis of the Distributed Scheduler in IEEE 802.16 Mesh Mode” Proc. ACM MobiHoc ’05, May 2005, pp.78-89. | zh_TW |
dc.relation.reference (參考文獻) | [4] N. Bayer, B. Xu, V. Rakocevic, and J. Habermann, “Improving the Performance of the distributed Scheduler in IEEE 802.16 Mesh Networks”, Proceedings of Vehicular Technology Conference (IEEE VTC), Dublin, Ireland, April 2007. | zh_TW |
dc.relation.reference (參考文獻) | [5] N. Bayer, B. Xu, V. Rakocevic, and J. Habermann, “Transmission Timing of Messages in IEEE 802.16 based Mesh Networks”, Proceedings of IEEE/VDE European Wireless, Athens, Greece, April, 2006. | zh_TW |
dc.relation.reference (參考文獻) | [6] M.S. Kuran, B. Yilmaz, F. Alagoz, and T. Tugcu, “Quality of service in mesh mode IEEE 802.16 networks”, 14th International Conference on Software, Telecommunications and Computer Networks 2006, (SoftCOM `06), Split-Dubrovnik, Croatia, 2006, pp. 107-111. | zh_TW |
dc.relation.reference (參考文獻) | [7] K. Wongthavarawat, and A. Ganz, “Packet Scheduling for QoS support in IEEE 802.16 broadband wireless access systems”, Int. J. Commun. Syst. Vol. 16, Issue 1, pp: 81--96, 2003. | zh_TW |
dc.relation.reference (參考文獻) | [8] S.Y. Wang, C.L. Chou, C.H. Huang, C.C. Hwang, Z.M. Yang, C.C. Chiou, and C.C. Lin, "The Design and Implementation of the NCTUns 1.0 Network Simulator," Computer Networks, Vol. 42, Issue 2, June 2003, pp.175-197. | zh_TW |