藍芽技術聯盟最新釋出的Bluetooth mesh提供裝置間可多對多傳輸，提升大範圍傳感網路的通訊效能。此外Bluetooth mesh的眾多設計是為商用市場及工業環境提供擴充性、穩定性及安全性。因此在智慧建築、智慧工業、智慧城市等新興市場上Bluetooth mesh扮演不可或缺的角色。目前Bluetooth mesh的網路協定“管理氾濫式路由法(managed flooding)”，是以典型的氾濫式路由法(flooding)為基礎，並為此設計一些優化機制來改善氾濫式路由法的缺點。為了探討管理氾濫式路由法在網狀網路(mesh network)的效能，本研究在網路模擬器- OMNeT++上實作Bluetooth mesh的網路協定及傳輸行為，並運用我們實作的藍芽模組模擬網狀網路封包傳遞情形。在模擬過程中我們找出管理氾濫式路由法所面臨的問題，並提出四種改善協定。為了探討在不同網路情境下五種協定的性能，我們設計四種網路情境並分析優缺點。最後，我們針對不同網路情境下應使用何種協定提出建議。

The Bluetooth mesh is the latest version of Bluetooth specifications released by the Bluetooth Special Interest Group (SIG). It provides many-to-many transmission among devices and improves the communication performance of a large-scale sensor networks. Besides, many of the designs of Bluetooth mesh provide scalability, stability, and security for commercial and industrial environments. The network protocol of Bluetooth mesh is “managed flooding,” which is based on the conventional flooding mechanism with some additional optimization mechanisms for mitigating the shortcomings inherent in the conventional flooding. To evaluate the performance of managed flooding, this work implements the network protocol and transmission behavior of the Bluetooth mesh on the network simulator—OMNeT++ and uses the implemented Bluetooth model to simulate the packet transmissions in the mesh network. According to the simulations, we observed the problems inherent in managed flooding. Then, we propose four protocols for performance improvement. In addition, we consider four network scenarios for performance evaluation and comparison in the simulations. Finally, we propose some recommendations for the use of protocols under different network scenarios.

致謝 II
中文摘要 III
ABSTRACT IV
CONTENTS V
LIST OF FIGURES VII
LIST OF TABLES IX
Chapter 1 Introduction 1
1.1 Research Motivation and Purposes 1
1.2 Research Method 2
1.3 Related Works 4
Chapter 2 General Background Information 6
2.1 The Evolution of Bluetooth 6
2.2 Bluetooth Mesh 8
2.2.1 Node 8
2.2.2 Bluetooth Mesh Stack 10
2.2.3 Networking Technology 12
2.2.3.1 Retransmit 13
2.2.3.2 Transmission Behavior 14
2.2.4 PDU Type 16
2.3 Bluetooth Low Energy (BLE) 18
2.3.1 Physical Layer 18
2.3.2 Advertising 19
2.3.3 Scanning 21
2.3.3.1 Passive Scanning 22
2.3.3.2 Active Scanning 23
2.4 OMNeT++ 23
Chapter 3 Bluetooth Model Design 26
3.1 Application Layer 28
3.2 Network Layer 29
3.2.1 Collector 30
3.2.2 Managed_Flooding 31
3.3 Data Link Layer 36
3.3.1 Logic Link Control (LLC) 36
3.3.2 Agent 37
3.3.3 Mgmt 37
3.3.4 Mac 39
3.4 Physical Layer 42
Chapter 4 Simulation Setting 44
4.1 Basic Mesh Network 44
4.2 Module Parameter Setting 45
4.2.1 Transmitting Behavior Setting 45
4.2.2 Receiving Behavior Setting 46
Chapter 5 Proposed Networking Protocols 48
5.1 Random Channel Order 48
5.2 Random Channel Order with A Fixed Delay Time 50
5.3 Random Backoff Time 51
5.4 Hybrid Random Channel Order 53
Chapter 6 Simulation Results 56
6.1 Scale-based Simulation Results 56
6.2 Density-based Simulation Results 60
6.3 Extended Discussion - K_max 65
6.4 High Traffic Intensity Test 67
Chapter 7 Conclusion 72
References 73

[1] J. Gubbi, R. Buyya, S. Marusic and M. Palaniswami, “Internet of Things (IoT): A vision, architectural elements, and future directions,” Future generation computer systems, v.29, no. 7, pp. 1645-1660, 2013.
[2] Bluetooth SIG, “Mesh Profile Specification 1.0.1,” [Online]. Available: https://www.bluetooth.com/specifications/mesh-specifications/.
[3] Techopedia - The IT Education Site, “Broadcast Storm,” [Online]. Available: https://www.techopedia.com/definition/6270/broadcast-storm.
[4] László Kajdocsi and János Kovács, “Issue on implementation Possibility of Bluetooth Mesh Capabilities into OmNET++,” 2018 IEEE 16th International Symposium on Intelligent Systems and Informatics (SISY), pp. 203-208, 2018.
[5] “The Network Simulator - ns-2,” [Online]. Available: https://www.isi.edu/nsnam/ns/.
[6] “ns-3 Neetwork Simulator,” [Online]. Available: https://www.nsnam.org/.
[7] “OMNeT++ Discrete Event Simulator,” [Online]. Available: https://omnetpp.org/.
[8] “GLOMOSIM Simulator,” [Online]. Available: http://networksimulationtools.com/glomosim-simulator-projects/.
[9] “JSim Home Page,” [Online]. Available: https://www.physiome.org/jsim/.
[10] H.-S. Kim, J. Lee and J. W. Jang, “BLEmesh: A Wireless Mesh Network Protocol for Bluetooth Low Energy Devices,” 3rd International Conference on Future Internet of Things and Cloud (FiCloud), pp. 558-563, 2015.
[11] P. Zenker, S. Krug, M. Binhack and J. Seitz, “Evaluation of BLE Mesh capabilities: A case study based on CSRMesh,” Proc. Int. Conf. Ubiquitous Future Netw. (ICUFN), pp. 790-795, 2016.
[12] Y. Murillo, B. Reynders, A. Chiumento, S. Malik, P. Crombez and S. Pollin, “Bluetooth now or low energy: Should BLE mesh become a flooding or connection oriented network?,” 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), pp. 1-6, 2017.
[13] E. A. J. Hansen, M. H. Nielsen, D. E. Serup, R. J. Williams, T. K. Madsen and R. Abildgren, “On Relay Selection Approaches in Bluetooth Mesh Networks,” 2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), pp. 1-5, 2018.
[14] Bluetooth SIG, “The history of the Bluetooth SIG,” [Online]. Available: https://www.bluetooth.com/about-us/our-history/.
[15] Wikipedia contributors, “Piconet,” [Online]. Available: https://en.wikipedia.org/wiki/Piconet.
[16] Kai-Ren, “Provisioning a Bluetooth Mesh Network Part 1,” [Online]. Available: https://www.bluetooth.com/blog/provisioning-a-bluetooth-mesh-network-part-1/.
[17] Kai-Ren, “Provisioning a Bluetooth Mesh Network Part 2,” [Online]. Available: https://www.bluetooth.com/blog/provisioning-a-bluetooth-mesh-network-part-2/.
[18] Bluetooth SIG Proprietary, “Mesh system architecture,” Mesh Profile Specification 1.0.1, v1.0.1, p. 331, January 2019.
[19] Wikipedia contributors, “ISM band,” [Online]. Available: https://en.wikipedia.org/wiki/ISM_band.
[20] Bluetooth SIG Proprietary, “Advertising events perturbed in time using advDelay,” Core Specification, v5.1, p. 2751, January 2019.
[21] R. Schlager, The Osi Model: Simply Explained, vol.1, 2013.
[22] Bluetooth SIG, “Core Specification,” [Online]. Available: https://www.bluetooth.com/specifications/bluetooth-core-specification/.
[23] Nordic Semiconductor, “nRF52840 Product Specification v1.1”.