臺灣博碩士論文加值系統

在多重速率與多通道的IEEE 802.11無線網路中，鏈路速率、競爭視窗和頻道參數間的交互作用對系統效能的改進扮演很重要的角色。為了利用頻道的多樣性達成平行通訊，之前的研究提出一個能夠支援目前普遍使用的IEEE 802.11無線網路的通道跳頻機制(CHS)，而也設計相對應的通道路由協定(CDR)使節點在多跳階的情況下能夠做更有效率的傳輸。此外，在如此多樣性的通道下，每個通道也各自擁有不同的特性，而在利用不同速率傳輸時，值得注意的是為了能成功成解碼收到的封包，我們所需要訊號源與雜訊的比值(SINR)的門檻值也會不同。一旦無法成功解碼封包，802.11 Distributed coordination function (DCF) 與速率調整機制會同時作用大大抑制傳輸的意願；當成功解碼封包時，802.11 DCF 會將競爭視窗設為最小值並同時調升傳輸速率鼓勵通訊的進行。因此，將競爭視窗與傳輸速率的調整機制分開考量會對802.11系統效能造成損害，所以先前的研究中，提出了一套同時考慮競爭視窗與傳輸速率的適應性速率調整機制(EARC)。而在本論文中，我們使用一套開放原始碼的路由器軟體在真實多重速率、多通道的無線網路環境中實現我們上述所提到的EARC、CHS和CDR協定。我們在室內無線網路環境下實際操作並以吞吐量來評估我們系統，而實驗結果顯示，我們結合EARC、CHS和CDR所實作出的無線網路系統會優於其他基於 IEEE 802.11 b/g多重速率、多通道無線網路系統，也證實多通道、多重速率路由實際的無線環境下能改善系統效能。

In IEEE 802.11 multi-rate wireless networks with multiple orthogonal (non-overlapping) channels available, interoperability of link rate, contention window and channel parameters plays an important role in terms of system capacity. In order to achieve better spatial diversity, a multi-radio channel-hopping scheme (CHS) has been devised to utilize multiple orthogonal channels available in widespread IEEE 802.11-based wireless systems. A corresponding channel-diverse routing (CDR) protocol has been proposed to realize efficient multi-hop communications. Furthermore, radio channels possess varying transmission characteristics. When the channel condition is good, we tend to encourage the transmission by increasing the link rate while setting a smaller contention window, and vice versa. Link rate is associated with a certain required Signal-to-Interference-and-Noise Ratio (SINR) threshold for successfully decoding received packets. On transmission failure, both rate reduction and 802.11 DCF binary exponential backoff represent double penalties for this wireless link. On the other hand, once transmission succeeds, 802.11 DCF resets the backoff contention window to the minimum value. At the same time, traditional link adaptation may also decide to increase the data rate. We observe that the separate consideration of the link rate and backoff mechanism harms the 802.11 system performance. Thus, a new mechanism which jointly considers link rate and contention window together entitled Enhanced Adaptation of link Rate and Contention window, abbreviated as EARC, has been proposed. In this thesis, we further implement the aforementioned EARC, CHS and CDR mechanisms in a real multi-rate, multi-hop wireless networking testbed based on an open-source router software. Through extensive indoor experiments, we evaluate the operational performance in terms of data throughput. Experimental results show that the combination of EARC, CHS and CDR outperforms other strategies in static IEEE 802.11b/g multi-rate, multi-hop wireless environments.

目 錄

摘 要 .I
ABSTRACT II
誌 謝 III
目 錄 IV
表 目 錄 VI
圖 目 錄 VII
第 1 章 緒論……………………………………………………………………………….1
第 2 章 相關文獻………………………………………………………………………….3
2.1 多頻道無線網路……………………………………………………………………3
2.2 多重速率無線網路…………………………………………………………………4
2.2.1 IEEE 802.11 Standard 後退演算法…………………………………...4
2.2.2 Auto-rate Fallback (ARF)……………………………………………...5
2.2.3 Adaptation of Link Rate and Contention Window (ARC)……….…….5
2.2.4 Receiver-based Auto-rate (RBAR)…………………………………….6
第 3 章 多通道、多重速率無線網路系統……………………………………………….7
3.1 跳頻機制…………………………………………………………………………....7
3.2 多通道路由…………………………………………………………………………8
3.2.1 網路資訊交換…………………………………………………………...9
3.2.2 路由規劃………………………………………………………………...9
3.2.3 佇列管理…………...…………………………………………………..10
3.3 EARC協定…………………………………………………………………………11
第 4 章 多通道、多重速率無線網路系統路由器設計………………………………….18
4.1 WING 架構…………………………………………………………………………18
4.2 WING 封包…………………………………………………………………………19
4.3 WING 元件介紹……………………………………………………………………20
4.4 WING 路由器………………………………………………………………………22
4.5 多通道、多重速率路由器…………………………………………………………25
4.5.1 修改及新增的Element………………………………………………...25
4.5.2 多通道、多重速率路由器架構……………………………………….28
第 5 章 網路實作環境…………………………………………………………………...30
第 6 章 效能分析………………………………………………………………………...33
第 7 章 結論……………………………………………………………………………...42
參 考 文 獻……………………………………………………………………………...43

[1] “IEEE Standard for Information Technology-Telecommunications and Information Exchange Between Systems-Local and Metropolitan Area Networks-Specific Requirements- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications,” ANSI/IEEE Std 802.11, 1999 Edition (R2003), pages i-513, 2003.
[2] “Supplement to IEEE Standard for Information Technology - Telecommunications and Information Exchange Between Systems - Local and Metropolitan Area Networks - Specific Requirements. Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: High-Speed Physical Layer in the 5 GHz Band,” IEEE Std 802.11a-1999,1999.
[3] “Supplement to IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems-Local and Metropolitan Area Networks- Specific Requirements- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Higher-Speed Physical Layer Extension in the 2.4 GHz Band,” IEEE Std 802.11b-1999, pages i-90, 2000.
[4] “Draft Supplement to Standard [for] Information Technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Further Higher Data Rate Extension in the 2.4 GHz band (Amendment to IEEE Std 802.11, 1999 Edition),” IEEE Std P802.11g/D8.2, 2003.
[5] T.-Y. Lin, K.-R. Wu, and G.-C. Yin, “Channel-hopping Scheme and Channel-diverse Routing in Static Multi-radio Multi-hop Wireless Networks”. IEEE Transactions on Computers, 1(99):14, October 2013.
[6] T.-Y. Lin, C.-Y. Tsai, and K.-R. Wu, “EARC: Enhanced Adaptation of Link Rate and Contention Window for IEEE 802.11 Multi-Rate Wireless Networks,” IEEE Transactions on Communications, 60(9):2623-2634, September 2012.
[7] A. K. Das, R. Vijayakumar, and S. Roy. “Static Channel Assignment in Multi-Radio Multi-Channel 802.11 Wireless Mesh Networks: Issues, Metrics and Algorithms”. In Proc. IEEE GLOBECOM, pages 1-6, November 2006.
[8] M. Alicherry, R. Bhatia, and L. Li. “Joint Channel Assignment and Routing for Throughtput Optimization in Multi-radio Wireless Mesh Networks”. In Proc. ACM Mobicom, pages 59-72, September 2005.
[9] T.-Y. Lin, W.-H. Tam, K.-L. Fan, and Y.-C. Tseng. “Resource Planning and Packet Forwarding in Multi-Radio, Multi-Mode, Multi-Channel, Multi-Rate (M4) Wireless Mesh Networks”. Elsevier Computer Communications, 31(7):1329-1342, May 2008.
[10] A. Raniwala and T.-C. Chiueh. “Architecture and Algorithms for an IEEE 802.11-based Multi-Channel Wireless Mesh Network”. In Proc. IEEE INFOCOM, 3:2223-2234, March 2005.
[11] M. D. Felice, G. Zhu, and L. Bononi. “Future Channel Reservation Medium Access Control (FCR-MAC) Protocol for Multi-Radio Multi-Channel Wireless Mesh Networks”. In Proc. ACM PE-WASUN, pages 71-79, October 2008.
[12] R. Huang, H. Zhai, C. Zhang, and Y. Fang. “SAM-MAC: An Efficient Channel Assignment Scheme for Multi-Channel Ad Hoc Networks”. Elsevier Computer Networks, 52(8):1634-1646, June 2008.
[13] P. Kyasanur and N. H. Vaidya. “Capacity of Multi-Channel Wireless Networks: Impact of Number of Channels and Interfaces”. In Proc. ACM MobiCom, pages 43-57, August 2005.
[14] P. Kyasanur and N. H. Vaidya. “Routing and Link-Layer Protocols for Multi-Channel Multi-Interface Ad Hoc Wireless Networks”. Mobile Computing and Communications Review, 10(1):31-43, January 2006.
[15] J. S. Pathmasuntharam, A. Das, and A. K. Gupta. “Primary Channel Assignment based MAC (PCAM) – A Multi-Channel MAC Protocol for Multi-Hop Wireless Networks”. In Proc. IEEE Wireless Communications and Networking Conference, 2:1110-1115, March 2004.
[16] J. So and N. H. Vaidya. “Multi-Channel MAC for Ad Hoc Networks: Handing Multi-Channel Hidden Terminals Using a Single Transceiver”. In Proc. ACM MobiHoc, pages 222-223, May 2004.
[17] A. Tzamaloukas and J. J. Garcia-Luna-Aceves. “Channel-Hopping Multiple Access”. In Proc. IEEE International Conference on Communications, 1:415-419, June 2000.
[18] A. Tzamaloukas and J. J. Garcia-Luna-Aceves. “Channel-Hopping Multiple Access with Packet Trains for Ad Hoc Networks”. In Proc. IEEE International Conference on Mobile Multimedia Communications (MoMuC), 1:415-419, November 2000.
[19] P. Bahl, R. Chandra, and J, Dunagan. “SSCH: Slotted Seeded Channel Hopping for Capacity Improvement in IEEE 802.11 Ad-Hoc Wireless Networks”. In Proc. ACM MobiCom, pages 216-230, September 2004.
[20] A. Kamerman and L. Monteban, “WaveLAN®-II: a high-performance wireless LAN for the unlicensed band”. Bell Labs Technical Journal, 2(3):118-133, Summer 1997.
[21] A.-C. Li, T.-Y. Lin, and C.-Y. Tsai, “ARC: Joint Adaptation of Link Rate and Contention Window for IEEE 802.11 Multi-Rate Wireless Networks”. In Proc. IEEE SECON, pages 1-9, June 2009.
[22] G. Holland, N. Vaidya, and P. Bahl, “A Rate-Adaptive MAC Protocol for Multi-Hop Wireless Networks”. In Proc. ACM MobiCom, pages 236-251, July 2001.
[23] J. M. Howie. “Fields and Galois Theory [electronic resource]”. Springer-Verlag London Limitted, 2006.
[24] F. Calì, M. Conti, and E. Gregori, “Dynamic Tuning of the IEEE 802.11 Protocol to Achieve a Theoretical Throughput Limit”. IEEE/ACM Transactions on Networking, 8(6):785-799, December 2000
[25] J. Bicket, D. Aguayo, S. Biswas, and R. Morris, “Architecture and Evaluation of an Unplanned 802.11b Mesh Network”. In Proc. ACM MobiCom, pages 31-42, August 2005.
[26] F. Granelli, R. Riggio, T. Rasheed, and D. Miorandi, “WING/WORLD: An Open Experimental Toolkit for the Design and Deployment of IEEE 802.11-Based Wireless Mesh Networks Testbeds”. EURASIP Journal on Wireless Communication and Networking, 2010(12):17, April 2010.
[27] Qualcom Atheros, Inc. http://www.qca.qualcomm.com/.
[28] The Madwifi Project. http://madwifi-project.org/.
[29] Fedora Project. http://fedoraproject.org/.
[30] The Netperf hompage. http://www.netperf.org/netperf/.