近年來，裝置對裝置通訊 (Device-to-Device Communication) 吸引了許多人的注意力，因為它不需要基地台 (Access Point) 就能直接溝通。隨著裝置數量的增加，使用者想要利用裝置對裝置通訊的好處，進而讓使用者更有效率地使用資源。Wi-Fi直連（Wi-Fi Direct）是一種基於隨意網路 (Ad hoc) 的協定，旨在加速裝置間連線和通訊。然而，這些利用Wi-Fi直連實作的程式大多需要使用者手動設定，與裝置對裝置加速通訊的目標互相矛盾。並且，這些實作缺少路由 (Routing) 功能。在本篇論文當中，我們提出能夠自動化建立的跨群組通訊和基於無線自組網按需平面距離向量路由協議 (AODV) 的路由功能。除此之外，整體的方法能夠運行在未修改Android作業系統的行動裝置上。整體方法由兩部分組成，跨群組連線和繞徑實作。實驗結果顯示我們提出的方法能夠運行在市面上的智慧型手機裝置，並且減少網路壅塞。

Nowadays, Device-to-Device (D2D) communication, in which devices could communicate with other devices without existence of infrastructure, has drawn plenty of attention. Due to the rising number of devices, users tend to take the advantage of D2D communication, providing an efficient way to allow users to reuse all kinds of resources, especially Wi-Fi Direct. Wi-Fi Direct is a technology standardized by the Wi-Fi Alliance to facilitate the connection between devices without the presence of an Access Point based on IEEE 802.11. However, almost all of the implementations based on Wi-Fi Direct in these days require of manual setup, contradicting to the objective of D2D network that devices could be formed dynamically and automatically. In addition, many of them are lacking of routing functionality. In this thesis, we propose a method to automatically establish connections among groups and further construct routing path based on Ad hoc On-Demand Distance Vector Routing (AODV). Furthermore, this method could apply to non-rooted Android mobile devices. Our method consists of two stages—Cross-groups communications, and Reactive routing. Experimental results show that our method, on top of Android platform, could reduce the number of the packets among the network in comparison with flooding.

Acknowledgement iii
Abstract iv
Table of Contents vi
List of Figures ix
Chapter 1. Introduction 1
Chapter 2. Wi-Fi Direct Technology 3
2.1. Device Discovery 4
2.2. Service Discovery 5
2.3. Group Formation 6
2.3.1. Standard 6
2.3.2. Persistent Procedure 8
2.3.3. Autonomous Procedure 9
2.4. Wi-Fi Direct limitations in Android 10
2.4.1. IP Address Assignment 10
2.4.2. Inter-group communication 11
Chapter 3. Related Work 12
Chapter 4. Problem Statement 15
4.1. IP Conflict 15
4.2. Inter-group communication 18
Chapter 5. Proposed method 18
5.1. Role definition 18
5.2. Communication mechanism 20
5.3. Network topology 24
5.4. Packet format 25
5.4.1 Service discovery 25
5.4.2 Topology refinement 26
5.4.3 Route establishment 26
5.4.4 Data transmission 27
5.5. Cross-group Communication and Reactive Routing 27
5.5.1. Cross-group Communication—group Formation 27
5.5.2. Cross-group Communication—cluster Formation 32
5.5.3. Cross-group Communication—topology Refinement 34
5.5.4. Reactive Routing—routing establishment 38
5.5.5. Flow chart of our method 42
5.5.6. Data transmission 43
Chapter 6. Experimental Evaluation 44
6.1. Experiment Environment 44
6.2. Compared methods 45
6.3. Performance Evaluation 47
6.4. Extra experiment 51
Chapter 7. Conclusion 54
Bibliography 55

[1] Wi-Fi Alliance, Wi-Fi Peer-to-Peer (P2P) Technical Specification v1.7, 2018.
[2] 802. 11u-2011 – Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications Amendment 9: Interworking with External Networks.
[3] Online. Android Developers. https://developer.android.com
[4] Wi-Fi Alliance, Wi-Fi Protected Setup Specification v1.0h, Dec. 2006.
[5] Jian-ye Liu, and Jian-kun Yu, “Research on Development of Android Applications,” in Intelligent Networks and Intelligent Systems, 2011 International Conference, IEEE, pp. 69–72.
[6] R. Motta and J. Pasqual, “Wireless P2P: Problem or opportunity,” in Proceedings of the Second International Conference on Advances in P2P Systems, 2010.
[7] D. Camps-Mur, A. Garcia-Saavedra, and P. Serrano, “Device-to-device communications with Wi-Fi Direct: overview and experimentation,” IEEE wireless communications, vol. 20, no. 3, pp. 96–104, 2013.
[8] K. Jahed, O. Farhat, G. Al-Jurdi, and S. Sharafeddine, “Optimized group owner selection in Wi-Fi Direct networks,” in Software, Telecommunications and Computer Networks (SoftCOM), 2016 24th International Conference on, pp. 1–5, IEEE, 2016.
[9] A. A. Shahin and M. Younis, “A framework for p2p networking of smart devices using Wi-Fi Direct,” in Personal, Indoor, and Mobile Radio Communication (PIMRC), 2014 IEEE 25th Annual International Symposium on, pp. 2082–2087, IEEE, 2014.
[10] Y. Duan, C. Borgiattino, C. Casetti, C. F. Chiasserini, P. Giaccone, M. Ricca, F. Malabocchia, and M. Turolla, “Wi-Fi Direct multi-group data dissemination for public safety,” in WTC 2014; World Telecommunications Congress 2014; Proceedings of, pp. 1–6, VDE, 2014.
[11] P. Wong, V. Varikota, D. Nguyen, A. Abukmail, "Automatic Android based Wireless Mesh Networks," Informatica (Slovenia), 2014.
[12] A. A. Shahin and M. Younis, “Efficient multi-group formation and communication protocol for Wi-Fi Direct,” in Local Computer Networks (LCN), 2015 IEEE 40th Conference on, pp. 233–236, IEEE, 2015.
[13] A. A. Shahin and M. Younis, “IP subnet negotiation in Wi-Fi Direct for seamless multi-group communications,” in Wireless and Mobile Computing, Networking and Communications (WiMob), 2016 IEEE 12th International Conference on, pp. 1–7, IEEE, 2016.
[14] C. Casetti, C. F. Chiasserini, L. C. Pelle, C. Del Valle, Y. Duan, and P. Giaccone, “Content-centric routing in Wi-Fi Direct multi-group networks,” in World of Wireless, Mobile and Multimedia Networks (WoWMoM), 2015 IEEE 16th International Symposium on a, pp. 1–9, IEEE, 2015.
[15] G. Z. Khan, R. Gonzalez, E. Park and X. Wu, “A reliable multicast MAC protocol for Wi-Fi Direct 802.11 networks,” European Conference on Networks and Communications (EuCNC), pp. 224-228, 2015.
[16] Ting-Hao Yeh, “A Mechanism for Autonomous Multi-Group Formation and Communication in Wi-Fi Direct Device to Device Networks,” M.S. thesis, National Tsing Hua University, Hsinchu, Taiwan, 2016.
[17] Liang-Cheng Wang, “Design and Implementation of Automatic Wi-Fi Direct Multi-Group Formation and Cross-Group Communication over Android Mobile Phones,” M.S. thesis, National Tsing Hua University, Hsinchu, Taiwan, 2017.
[18] Mei-Chia Chiu, “Cluster Formation and Refinement for Wi-Fi Direct,” M.S. thesis, National Tsing Hua University, Hsinchu, Taiwan, 2018.
[19] Zong-Zhe Yang, “Autonomous Multi-Hop Wi-Fi Direct Network Formation: Middleware and Application Programming Interface Design,” M.S. thesis, National Tsing Hua University, Hsinchu, Taiwan, 2018.
[20] Paul Gardner-stephen, Andrew Bettison, Romana Challans and Jeremy Lakeman, “The Rational behind the Serval Network Layer for resistant communications,” Journal of Computer Science, pp. 1680-1685, 2013.