近年來無線網路蓬勃發展，IEEE 802.11ax把目標放在提升密集無線區域網路環境下的傳輸效能。為此TGax的幾位成員於2015年發布了一項動態靈敏度控制機制(Dynamic Sensitivity Control, DSC)來透過調整載波感測靈敏度以達到避開大量的隱藏節點提升傳輸效能。但是此動態靈敏度控制機制存在著一些問題。像是在運作動態靈敏度控制機制時容易形成過多的隱藏節點導致干擾；另外就是此機制並沒有考慮到結合頻道捆束機制(Channel Bonding)時所產生的問題。因此本論文設計了頻道捆束之碰撞避免動態靈敏度控制機制來解決上述的問題。之後再以NS3模擬器來模擬協定的運作情況。

Wireless networks have been deployed widely, the main topic of next generation IEEE802.11ax is to increase throughput on dense Wireless Local Area Networks. Some of IEEE 802.11ax Task Group (TGax) members have been actively involved in the design of Clear Channel Access (CCA) modification schemes, where Dynamic Sensitivity Control (DSC) algorithm has been proposed as one of the key innovative technologies to increase the spectral reuse. However, DSC scheme has drawbacks: it doesn’t consider about Channel Bonding and increase frame collisions as well as hidden node count. In this paper, we propose the DSC MAC protocol along with Channel Bonding and power control. Final this protocol will be simulated and compared with other DSC MAC protocols by NS3 Simulator.

目錄
第1章	緒論	1
1.1	前言	1
1.2	研究動機與目的	2
1.3	研究方法	2
1.4	論文架構	3
第2章	背景知識	4
2.1	頻道捆束基本介紹	4
2.1.1	頻道捆束技術(Channel bonding)	6
2.1.2	載波感測靈敏度	7
2.1.3	IEEE 802.11ac頻道捆束的存取方式	9
2.2	動態靈敏度控制機制(Dynamic Sensitivity Control, DSC)介紹	11
2.3	相關文獻	13
第3章	預備知識	15
3.1	問題陳述	15
3.2	相關假設	19
第4章	頻道捆束下動態靈敏度控制機制	20
4.1	初步分析	20
4.2	動態靈敏度控制機制與能量控制	28
(Dynamic Sensitivity Control with Power Control, DSC-PC)	28
第5章	效能分析	30
5.1	模擬場景與參數	30
5.2	實驗結果	31
5.2	實驗總結	32
第6章	結論	33
參考文獻	34
附錄A	37
附錄B	46

圖目錄
圖 1  ISM 2.4GHz band	4
圖 2  ISM 5GHz band 及頻道捆束技術	5
圖 3  IEEE 802.11ac存取方式	7
圖 4  靜態頻道存取模式	10
圖 5  動態頻寬存取模式	10
圖 6  STA收集接收訊號強度指標時序圖	11
圖 7  增加載波感測門檻值	12
圖 8 場景範例	15
圖 9 不對稱暴露節點問題	17
圖 10 過多暴露節點	18
圖 11 密集網路環境	20
圖 12  RTS/CTS無法完全警告	21
圖 13 干擾範圍	22
圖 14 避開干擾範圍	24
圖 15 載波感測範圍設定	24
圖 16 干擾範圍、傳輸範圍和載波感測範圍之間的關係	25
圖 17 頻道捆束數量不如預期時產生的碰撞	27
圖 18 DSC-PC運作流程圖	29
圖 19 總傳輸效能	31
圖 20 掉包率	32

表目錄
表 一、載波感測靈敏度(Carrier Sensing Threshold)	8
表 二、分散在各頻道上的傳輸能量	16
表 三、載波感測範圍	16
表 四、各個情況下的干擾範圍	23
表 五、新舊載波感測範圍比較	26
表 六、實驗參數	30

[1]	IEEE Std 802. 11ac-2013 ,part 11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications--amendment 4: Enhancements for very high throughput for operation in bands below 6 GHz.,2013.
[2]	IEEE Std 802. 11n-2009: part 11: Wireless LAN medium access control (MAC)and physical layer (PHY) specifications amendment 5: Enhancements for higher throughput.,2009
[3]	Minyoung Park, '"IEEE 802.11ac: Dynamic Bandwidth Channel Access," IEEE International Conference on Communications (ICC), 2011, pp. 1-5.
[4]	M.X. Gong, B. Hart, Liangfu Xia and R. Want, '"Channel Bounding and MAC Protection Mechanisms for 802.11ac," IEEE Global Telecommunications Conference (GLOBECOM 2011), 2011, pp. 1-5.
[5]	Seowoo Jang and Saewoong Bahk, "A Channel Allocation Algorithm for Reducing the Channel Sensing/Reserving Asymmetry in 802.11ac Networks," IEEE Transactions on Mobile Computing, vol. 14, no. 3, pp. 458-472.
[6]	IEEE 802.11 Task Group AX, “Status of Project IEEE 802.11ax High Efficiency WLAN (HEW)”; accessed July 2015, http://www.ieee802.org/11/Reports/tgax_update.htm, 2015.
[7]	Boris Bellalta,”IEEE 802.11ax: High-Efficiency WLANs,” IEEE Wireless Communications, 2016.
[8]	B. Bellalta, L. Bononi, R. Brunoc, and A. Kasslerd, “Next Generation IEEE 802.11 Wireless Local Area Networks: Current Status, Future Directions and Open Challenges”, International Journal for the Computer and Telecommunications Industry, 2015.
[9]	Kuei-Ping Shih,Yen-Da Chen,Chau-Chieh Chang,”A Physical/Virtual Carrier-Sense-Based Power Control MAC Protocol for Collision Avoidance in Wireless Ad Hoc Networks” IEEE Transactions on Parallel and Distributed Systems,2011
[10]	M. Shahwaiz Afaqui,Eduard Garcia-Villegas,Elena Lopez-Aguilera,Graham Smith, Daniel Camps,”Evaluation of Dynamic Sensitivity Control Algorithm for IEEE 802.11ax”IEEE Wireless Communications and Networking Conference (WCNC),2015
[11]	S. Afaqui, E.G. Villegas, E.L. Aguilera, G. Smith, and D. Camps, “Evaluation of Dynamic Sensitivity Control Algorithm for IEEE 802.11ax”, in Proceedings of IEEE Wireless Communications and Networking Conference (WCNC), 2015.
[12]	S. Afaqui, E.G. Villegas, and E.L. Aguilera, “Dynamic Sensitivity Control Algorithm Leveraging Adaptive RTS/CTS for IEEE 802.11ax”, in Proceedings of IEEE Wireless Communications and Networking Conference (WCNC), 2016.
[13]	Z. Zhong, F. Cao, P. Kulkarni, and Z. Fan, “Promise and Perils of Dynamic Sensitivity Control in IEEE 802.11ax WLANs”, in Proceedings of International Symposium Wireless Communication Systems (ISWCS), 2016.
[14]	S. Afaqui, E.G. Villegas, E. L. Aguilera, and D.C. Mur, “Dynamic Sensitivity Control of Access Points for IEEE 802.11ax”, in Proceedings of IEEE ICC Mobile and Wireless Networking Symposium, 2016.
[15]	Shih, Kuei-Ping, and Yen-Da Chen. "CAPC: A collision avoidance power control MAC protocol for wireless ad hoc networks." IEEE Communications Letters 9.9 (2005): 859-861.
[16]	Chen, Yen-Da, Chia Chuang, and Kuei-Ping Shih. "A channel bonding MAC protocol for IEEE 802.11 ac WLANs." Ubiquitous and Future Networks (ICUFN), 2017 Ninth International Conference on. IEEE, 2017.
[17]	White Paper: IEEE 802.11ac Migration Guide, http://enterprise.netscout.com/content/white-paper-ieee-80211ac-migration-guide.
[18]	The Network Simulator – 3, [Online] Available: https://www.nsnam.org
[19]	D-J. Deng, K-C. Chen, and R-S. Cheng, “IEEE 802.11ax: Next Generation Wireless Local Area Networks,” in Proceedings of EAI International Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness (QSHINE), 2014.
[20]	M.Gong, B. Hart, L. Xia, and R. Want, “Channel Bounding and MAC Protection Mechanisms for 802.11ac,” in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM), 2011.