透過無線電波傳輸資料所發展的無線傳輸技術已經行之有年。其中以IEEE 802.11所制定的DCF機制最具盛名。然而在傳輸時所帶來的干擾問題以及水下環境中的巨大傳播延遲(Propagation Delay)特性，將使得針對無線電波傳輸所設計的媒介存取控制(MAC)協定，在水下聲波網路中已不適用。本篇論文主要探討在水下使用DCF機制所帶來的干擾問題，以及巨大傳播延遲帶來的隱藏節點問題。透過分析水下聲波傳輸的訊號衰減，提出一套新的運作機制，在考量訊號干擾下，藉以調整封包傳輸所使用的訊號強度，來減少網路上封包的碰撞，進而提升整體網路效能。最後透過實驗模擬，發現本篇論文所提出的運作機制，在網路傳輸效能以及資料傳輸碰撞的表現上有顯著的改善。

Wireless technology has been developed and used for many years. Due to the nature of water, instead of radio wave, sound wave is used for underwater transmission. However, it will waste a lot of time for propagation at every transmission. Recently, IEEE 802.11 DCF is the most famous MAC protocol but is not suitable for underwater scenarios. We figure out the attenuation of acoustic in underwater and interference problem through our analysis. Therefore, this proposal mainly focuses on how to modify the MAC protocol for underwater acoustic network. It can avoid collisions by power control when sending control packets in our proposed protocol. In simulation, our protocol can outperform than other protocols in network throughput and number of collisions.

目錄
第1章	緒論	1
1.1	前言	1
1.2	研究動機與目的	3
1.3	研究方法	4
1.4	論文架構	5
第2章	預備知識	6
2.1	問題描述	6
2.1.1 Control/DATA Collision (CDC)	6
2.1.1.1 相關文獻	10
2.1.2 Large Interference Range Collision (LIRC)	12
2.1.2.1 相關文獻	14
第3章	聲波與訊號分析	15
3.1	聲波衰減	15
3.2	封包成功接收之條件	17
3.2.1	接收端之訊號雜訊比	18
第4章	電量控制之碰撞避免媒介存取控制協定	25
4.1	基本理念	25
4.2	電量控制	28
4.3	電量控制之碰撞避免媒介存取控制協定	31
第5章	實驗模擬	33
5.1	實驗場景與參數設定	33
5.2	實驗結果及分析	34
第6章	結論	42
參考文獻	43
附錄 英文論文	47
 
圖目錄
圖 1:隱藏節點示意圖。	1
圖 2:A、B節點和收送端之間的不同傳播延遲。	4
圖 3:無線電波和聲波所造成的傳播延遲差異。	6
圖 4:RTS封包與DATA封包碰撞。	7
圖 5:CTS封包與DATA封包碰撞。	7
圖 6:RTS/CTS覆蓋情形。	9
圖 7:CDC問題之影響。	10
圖 8:Slotted FAMA運作機制。	11
圖 9:PCAP運作機制。	12
圖 10:發生在IR底下的封包碰撞。	13
圖 11:聲波擴散方式。	15
圖 12:吸收係數。	16
圖 13:聲波衰減。	17
圖 14:干擾範圍。	21
圖 15:RTS/CTS在干擾範圍下的覆蓋情形。	22
圖 16:LIRC問題之影響。	23
圖 17:CDC與LIRC問題之影響力比較。	24
圖 18:節點使用Pmax傳送封包碰撞例子(以時間軸表示)。	25
圖 19:節點使用Pmax傳送封包碰撞例子(以空間表示)。	26
圖 20:較小的干擾範圍且I節點並不坐落於干擾範圍內。	27
圖 21:水下網路中所期望的干擾範圍大小。	28
圖 22:TLPC運作例子(以時間軸表示)。	32
圖 23:TLPC運作例子(以空間表示)。	32
圖 24:網格狀拓樸。	33
圖 25:網路流量與網路效能之關係。	34
圖 26:網路流量與封包碰撞次數之關係。	35
圖 27:網路流量與電量消耗之關係。	36
圖 28:網路流量與達成1 bit Throughput的電量消耗之關係。	37
圖 29:隨機拓樸下網路流量與網路效能之關係。	38
圖 30:隨機拓樸下網路流量與網路效能之關係。	39
圖 31:隨機拓樸下網路流量與電量消耗之關係。	40
圖 32:隨機拓樸下網路流量與達成1 bit Throughput的電量消耗之關係。	41
 
表目錄
表 1.水下聲波網路與一般無線網路之比較	2
表 2.實驗的模擬參數設定	33

[1]	L. Berkhovskikh and Y. Lysanov, Fundamentals of Ocean Acoustics, New York: Springer, 1982.
[2]	IEEE. IEEE Std 802.11-1999, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Aug. 1999.
[3]	E. M. Sozer, M. Stojanovic, and J. G. Proakis, “Underwater Acoustic Networks,” IEEE Journal of Oceanic Engineering, vol. 25, no. 5, pp. 72-83, Jan. 2000.
[4]	T. Rappaport, Wireless Communications: Principles and Practice, 2nd ed. Prentice Hall: New Jersey, 2002.
[5]	K. Xu, M. Gerla, and S. Bae, “How effective is the IEEE 802.11 RTS/CTS handshake in ad hoc networks?” in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM), vol. 1, 2002, pp. 72–76.
[6]	F. Ye, S. Yi, and B. Sikdar, “Improving spatial reuse of IEEE 802.11 based ad hoc networks,” in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM), vol. 2, 2003, pp. 1013–1017.
[7]	M. Molins, M. Stojanovic, “Slotted FAMA a MAC protocol for underwater acoustic networks,” in Proceedings of the IEEE OCEANS, Sep. 2006, pp. 1–7.
[8]	M. Stojanovic, “On the Relationship between Capacity and Distance in a Underwater Acoustic Communication Channel,” in Proceedings of the ACM International Workshop on UnderWater Networks (WUWnet), Sep. 2006.
[9]	P. Borja and M. Stojanovic, “A MAC Protocol for Ad-Hoc Underwater Acoustic Sensor Networks,” in Proceedings of the ACM International Workshop on UnderWater Networks (WUWnet), Sep. 2006
[10]	X. Guo, M. R. Frater, and M. Ryan, “A propagation-delay-tolerant collision avoidance protocol for underwater acoustic sensor networks,” in Proceedings of the OCEANS, May 2007.
[11]	X. Guo, M. R. Frater, and M. Ryan, “An adaptive propagation-delay-tolerant MAC protocol for underwater acoustic sensor networks,” in Proceedings of OCEANS, Jun. 2007, pp. 1–5.
[12]	Lucani, D.E.; Stojanovic, M.; Medard, M., “On the Relationship between Transmission Power and Capacity of an Underwater Acoustic Communication Channel,” in Proceeding of OCEANS, 8-11 Apr. 2008.
[13]	N. Chirdchoo, W.-S. Soh, and K. C. Chua, “MACA-MN: A MACA-based MAC protocol for underwater acoustic networks with packet train for multiple neighbors,” in Proceedings of the IEEE Vehicular Technology Conference (VTC), May 2008, pp. 46–50.
[14]	N. Chirdchoo, W.-S. Soh, and K. C. Chua, “RIPT: A receiver-initiated reservation-based protocol for underwater acoustic networks,” IEEE Journal on Selected Areas in Communications (JSAC), vol. 9, no. 9, pp. 1744–1753, Sep. 2008.
[15]	H. H. Ng, W. S. Soh, and M. Motani, “MACA-U: A Media Access Protocol for Underwater Acoustic Networks” in Proceeding of the IEEE Global Telecommunication Conference (Globecom), Nov. 2008.
[16]	E. Cheng, B. Lin, F. Yuan and J. Deng, “A Modified Multiple Access Protocol for Underwater Acoustic Networks,” in Proceeding of the WNIS, May 2009, pp.46-49.
[17]	Y. Zhong, J. Huang, J. Han, “A Delay-tolerant MAC Protocol with Collision Avoidance for Underwater Acoustic Networks,” in Proceedings of the International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), 2009, pp. 1–4.
[18]	X. Guo, M. Frater, and M. Ryan, “Design of a propagation-delay-tolerant MAC protocol for underwater acoustic sensor networks,” IEEE Journal of Oceanic Engineering, vol. 34, pp. 170–180, 2009.
[19]	Sun Yi, Patrick W. Nelson, A. Galip Ulsoy, Time-Delay Systems: Analysis and Control Using the Lambert W Function ” World Scientific Pub Co Inc, 2010.
[20]	Y. Noh, P. Wang, U. Lee, D. Torres and M. Gerla, “DOTS: A Propagation Delay-aware Opportunistic MAC Protocol for Underwater Sensor Networks,” in Proceeding of the ICNP, May 2010, pp.183-192. 
[21]	Z. Azar and M. Taghi Manzuri, “A Latency-Tolerant MAC Protocol for Underwater Acoustic Sensor Networks,” in Proceeding of the ICCAS, Nov. 2010, pp.849-854.
[22]	D. Fang, Y. Li, H. Huang and L. Yin, “A CSMA/CA-based MAC Protocol for Underwater Acoustic Networks,”  in Proceedings of the International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), May 2010, pp.1-4.
[23]	K.-P. Shih, Y.-D. Chen, and C.-C. 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, VOL. 22, NO. 2, Feb. 2011.
[24]	K.-P. Shih and Y.-D. Chen, “CAPC: A collision avoidance power control MAC protocol for wireless ad hoc networks,” IEEE Communications Letters, vol. 9, no. 9, pp. 859–861, Sep. 2005.
[25]	K.-P. Shih, Y.-D. Chen, and C.-C. Chang, “Adaptive range-based power control for collision avoidance in wireless ad hoc networks,” in Proceedings of the IEEE International Conference on Communications (ICC), Jun. 2007.
[26]	E. S. Jung and N. H. Vaidya, “A power control MAC protocol for ad hoc networks,” in Proceedings of the ACM International Conference on Mobile Computing and Networking (MOBICOM), 2002, pp. 36–47.
[27]	Y. Zhou and S. M. Nettles, “Balancing the hidden and exposed node problems with power control in CSMA/CA-based wireless networks,” in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), 2005, pp. 683–688.
[28]	J. Zhang, Z. Fang, and B. Brahim, “Adaptive power control for single channel ad hoc networks,” in Proceedings of the IEEE International Conference on Communications (ICC), 2005, pp. 3156–3160.
[29]	The Network Simulator – 2, [Online] Available: http://www.isi.edu/nsnam/ns/.
[30]	IEEE Std 802.11g-2003, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications–Amendment 4:  Further Higher Data Rate Extension in the 2.4 GHz Band, IEEE, Jun. 2003.
[31]	T.-S. Kim, J. C. Hou, and H. Lim, “Improving spatial reuse through tuning transmit power, carrier sense threshold, and data rate in multihop wireless networks,” in Proceedings of the ACM International Conference on Mobile Computing and Networking (MOBICOM), 2006, pp. 366–377.