本論文針對同頻全雙工無線區域網路(In-Band Full Duplex Wireless LANs, IBFD WLANs)中，非對稱傳輸下所造成的效能下降問題，提出一有效的解決策略。隨著天線設計與訊號處理的新進展，使得使用者能透過相同的頻道同時發送與接收資料，該技術稱之為同頻全雙工。然而實體層的進步，需要搭配有效的IBFD媒體存取控制(MAC)協定以達到更佳的效益。另外，由於上傳與下載的傳輸流量通常都不相同，使得在進行IBFD傳輸時，容易產生頻道閒置的浪費。因此本論文提出一頻道竊用的媒體存取控制協定，簡稱為Channel-Stealing Full Duplex (CSFD) MAC，以解決上傳-下載傳輸鏈路的非對稱傳輸問題。CSFD的特色是竊用因非對稱傳輸所產生的頻道閒置時間，增加傳輸機會，以提昇非對稱傳輸之效能。本論文透過OMNET++模擬器與其他相關研究進行比較，結果顯示CSFD在不同的非對稱傳輸場景中，效能與傳輸延遲都優於半雙工與相關研究，且較適用於未來的IBFD WLANs。

This paper proposes an effective solution to the performance degradation caused by asymmetric transmission in In-Band Full-Duplex Wireless LANs (IBFD WLANs). Along with antenna design and signal processing advancements, users can simultaneously send and receive data through the same channel, which is called IBFD transmission. However, advancements in the physical layer, efficient IBFD Medium Access Control(MAC) protocol is required to achieve optimum benefit from this latest technology. Moreover, since transmission traffic of uplink and downlink is usually different, so IBFD transmission is easy to generate waste of channel idleness. Therefore, in this paper, a Channel-Stealing Full Duplex (CSFD) MAC is proposed to solve the asymmetric transmission problem in the uplink-downlink transmission. The main feature of CSFD is increasing transmission opportunities by stealing channel idle time due to asymmetric trans-mission to improve the performance of the asymmetric transmission. CSFD compares with the related research (A-duplex) by OMNET++ simulator. The simulation results suggest that the throughput and transmission delay of CSFD outperforms traditional half-duplex and A-Duplex in different asymmetric transmission scenarios, which can be used for future FD WLANs.

目錄
第1章	緒論	1
1.1前言	1
1.2研究動機	3
1.3研究目的	5
1.4論文架構	5
第2章	背景知識	6
2.1全雙工的傳輸模式	6
2.2捕獲效應	8
2.3文獻探討	10
第3章	問題陳述	18
3.1預設問題	18
3.1.1非對稱傳輸浪費問題(Wastage Problem)	18
3.1.2 ACK接收問題(ACK Receiving Problem, ARP)	19
3.1.3上行-下行干擾 (Uplink-Downlink Interference, UDI)	20
第4章	非對稱流量傳輸之頻道竊用全雙工媒體存取控制協定	23
4.1考慮場景	23
4.2 CSFD MAC協定	24
4.2.1 CSFD MAC在LDL的作法	25
4.2.2 CSFD MAC在LUL的作法	28
4.3 CSFD MAC控制訊框格式	32
4.4 CSFD MAC運作流程	34
第5章	效能分析	40
5.1模擬場景與參數	40
5.2實驗結果	40
5.3實驗總結	48
第6章	結論	49
6.1貢獻	49
6.2未來工作	49
參考文獻	50
附錄A	54
附錄B	62
 
圖目錄
圖 一、IBFD WLANs中的傳輸干擾	2
圖 二、全雙工的傳輸模式	6
圖 三、單向全雙工模式的發起模式	7
圖 四、捕獲效應的假設環境	8
圖 五、Data2為-49dBm的情況	9
圖 六、Data2為-89dBm的情況	9
圖 七、非對稱傳輸模式	11
圖 八、RTS/CTS 全雙工	11
圖 九、LDL使用Delay time情況	12
圖 十、LUL使用Busy Tone情況	13
圖 十一、AP無適當資料封包傳輸的情況	15
圖 十二、雙向傳輸補上Busy Tone的情況	16
圖 十三、雙向傳輸補上中斷資料傳輸的情況	16
圖 十四、Asym-MAC	17
圖 十五、非對稱傳輸，下行資源浪費	19
圖 十六、非對稱傳輸，上行資源浪費	19
圖 十七、ACK接收問題	20
圖 十八、第一次上行-下行干擾	21
圖 十九、接續資料上行-下行干擾	22
圖 二十、密集節點場景	23
圖 二十一、緩解上行-下行干擾	24
圖 二十二、DRTS示意圖	25
圖 二十三、LDL-FCTS示意圖	26
圖 二十四、LDL模式下，增加其他節點的傳輸機會	27
圖 二十五、MDA示意圖	28
圖 二十六、LUL希望竊用時間示意圖	28
圖 二十七、LUL-FCTS	29
圖 二十八、LUL-FCTS示意圖	30
圖 二十九、DRTS示意圖	30
圖 三十、ACK的回覆	31
圖 三十一、控制訊框格式	32
圖 三十二、CSFD MAC中AP運作流程	35
圖 三十三、CSFD MAC中STA運作流程	37
圖 三十四、CSFD協定，LDL模式底下54Mbps的效能	41
圖 三十五、CSFD協定，LDL模式底下18Mbps的效能	41
圖 三十六、CSFD協定，LDL模式底下UL資料傳輸延遲時間	42
圖 三十七、CSFD協定，LUL模式底下54Mbps的效能	43
圖 三十八、CSFD協定，LUL模式底下18Mbps的效能	43
圖 三十九、LUL，DL資料傳輸延遲時間	44
圖 四十、LDL，距離與效能分析圖	45
圖 四十一、LUL，距離與封包接收分析圖	46
圖 四十二、LUL，距離與效能分析圖	47
圖 四十三、LUL，距離與封包接收分析圖	48
 
表目錄
表 一、模擬參數	40
 
演算法目錄
Algorithm 1 CSFD MAC for AP execution	38
Algorithm 2 CSFD MAC for STA execution	39

參考資料
[1].	W. Lin , B. Li, M. Yang, Q. Qu, Z. Yan, X. Zuo and B. Yang, “Integrated Link-System Level Simulation Platform for the Next Generation WLAN - IEEE 802.11ax,” in Proceedings of IEEE Global Communications Conference (GLOBECOM), 2016.
[2].	Status of Project IEEE 802.11ax, High Efficiency WLAN Study Group (HEW SG), High Efficiency WLAN. [Online]. Available: http://www.ieee802.org/11/Reports/tgax_update.htm.
[3].	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.
[4].	D. Kim, H. Lee, and D. Hong, “A survey of in-band full-duplex transmission: From the perspective of PHY and MAC layers,” IEEE Commun. Surveys Tuts., vol. 17, no. 4, pp. 2017–2046, Fourth Quart.2015.
[5].	Z. Yang, Z. Wang and Q. Zhang, “Relieving 802.11 Performance Anomaly with Full Duplex Communication,” in Proceedings of IEEE Global Communications Conference (GLOBECOM), 2016.
[6].	A. Tang and X. Wang,” Medium Access Control for a Wireless LAN with aFull Duplex AP and Half Duplex Stations”, in Proceedings of IEEE Global Telecommunications Conference (GLOBECOM), 2014.
[7].	S. Khaledian, F. Farzami, B. Smida and D. Erricolo, “Inherent Self-Interference Cancellation for In-Band Full-Duplex Single-Antenna Systems,” IEEE Transactions on Microwave Theory and Techniques, vol. 66, pp. 2842-2850, 2018.
[8].	A. Tang and X. Wang, “Balanced RF-circuit based self-interference cancellation for full duplex communications,” Ad Hoc Netw., vol. 24, pp. 214–227, Jan. 2015.
[9].	M. Sakai, H. Lin, and K. Yamashita, “Adaptive cancellation of self-interference in full-duplex wireless with transmitter iq imbalance,” in Proceedings of IEEE Global Communications Conference (GLOBECOM), 2014, pp. 3220–3224.
[10].	S. Sen, N. Santhapuri, R. R. Choudhury and S. Nelakuditi, “Successive Interference Cancellation: A Back-of-the-envelope Perspective,” in Proceedings of ACM SIGCOMM Workshop on Hot Topics in Networks, ser. Hotnets-IX. New York, NY, USA: ACM, 2010, pp. 17:1–17:6.
[11].	S. Y. Chen, T. F. Huang, K. C. J. Lin, Y.-W. Hong and A. Sabharwal, “Probabilistic Medium Access Control for Full-Duplex Networks With Half-Duplex Clients,” IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, vol.16, n0.4, 2017.
[12].	Q. Qu, B. Li, M. Yang, Z. Yan and X. Zuo, “MU-FuPlex a Multiuser Full-duplex MAC Protocol for the Next Generation Wireless Networks,” in Proceedings of IEEE Wireless Communications and Networking Conference (WCNC), 2017.
[13].	A. Tang and X. Wang, “A-Duplex Medium Access Control for Efficient Coexistence between Full-Duplex and Half-Duplex Communications,” IEEE Transactions on Wireless Communications, vol. 14, no. 10, pp. 5871 - 5885, 2015.
[14].	J. K. Kim, W. K. Kim and J. H. Kim, ‘‘A New Full Duplex MAC Protocol to Solve the Asymmetric Transmission Time,’’ in Proceedings of IEEE Globecom Workshops (GC Wkshps), 2015.
[15].	M. A. Alim and T. Watanabe, “Full Duplex Medium Access Control Protocol for Asymmetric Traffic,” in Proceedings of IEEE Vehicular Technology Conference (VTC-Fall), 2016.
[16].	M. Murad and A. M. Eltawil, “A Simple Full-Duplex MAC Protocol Exploiting Asymmetric Traffic Loads in WiFi Systems,” in Proceedings of IEEE Wireless Communications and Networking Conference (WCNC), 2017.
[17].	A. Aijaz and P. Kulkami, “Protocol Design for Enabling Full-Duplex Operation in Next-Generation IEEE 802.11 WLANs,” IEEE Systems Journal, no .99, 2017.
[18].	J. Hu, B. Di, Y. Liao, K. Bian and L. Song, “Hybrid MAC Protocol Design and Optimization for Full Duplex Wi-Fi Networks,” IEEE Transactions on Wireless Communications, pp. 1 - 1, 2018.
[19].	S. Kim, M. S. Sim, C.-B. Chae and S. Choi, ‘‘Asymmetric simultaneous transmit and receive in WiFi networks,’’ IEEE Access, vol. 5, pp. 14079–14094, Jul. 2017.
[20].	J. Lee et al., ‘‘An experimental study on the capture effect in 802.11a networks,’’ in Proc. ACM WiNTECH, Sep. 2007, pp. 1–2
[21].	S. Yoo, Y. Shin, S. Kim, and S. Choi, “Toward realistic WiFi simulationwith smartphone “Physics”,” in Proceedings of IEEE WoWMoM, Jun. 2014, pp. 1-6.
[22].	J. Seddar, H. Khalife, W. A. Safwi and V. Conan, ‘‘A full duplex MAC protocol for wireless networks,’’ in Proceedings of International Wireless Communications and Mobile Computing Conference (IWCMC), 2015.
[23].	OpenSim Ltd., OMNeT++: Discrete Event Simulator, [Online] Availible : https://omnetpp.org/