指導教授：周俊廷臺灣大學：電信工程學研究所盧奕吾Lu, I-WuI-WuLu2014-11-302018-07-052014-11-302018-07-052014http://ntur.lib.ntu.edu.tw//handle/246246/264355M2M communication is an enabling solution for many applications, including industrial control and smart buildings. Take the temperature monitoring system for machinery in a factory as an example. The temperature sensors send back the readings to a central controller. The controller will shut down the system if the readings are over a predefined threshold. In smart buildings, lighting control systems consist of different sensors such as light sensors and motion sensors. These sensors detect the behaviors of human beings and turn on/off the lights accordingly. A common problem among the above applications is that many machines, especially the sensors, are usually battery-powered. Therefore, they have extremely limited energy budget. Given that it is also very inconvenient to replace or recharge the battery, how to maintain an M2M network in an energy-saving manner becomes a critical issue in the design of M2M networks. Turning the radio off whenever possible (i.e., duty cycling the machines) is one of the most common methods for energy management. Duty-cycle control, however, results in a longer latency of message dissemination. Although longer latency is not a serious problem for non-time critical messages such as regular temperature readings, it will lead to devastating results for time-critical messages such as fire alarms. Most of the existing researches focused on minimizing the latency of non-time critical messages or time-critical messages seperatedly. A joint design to make tradeoff between the latency of these two types of messages is still missing. In this thesis, a set of specially designed sequences that control the duty cycle of machines is developed to make a better tradeoff. Our simulation results show that the end-to-end latency of time-critical messages is shortened by 13% to 42% depending on the duty cycle, while that of non-time critical message is only increased by less than 7%. The proposed solution is also implemented in an IEEE 802.15.4 network. The result shows that our sequences can prolong the lifetime of machines by 22% to 333% and reduce the end-to-end delay by 26%.ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii CHAPTER 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . 1 1.1 An introduction to the low duty-cycle M2M network . . . . . . . . . 1 1.2 Problems in low duty-cycle networks . . . . . . . . . . . . . . . . . . 3 1.3 Asynchronous approaches . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3.1 The tradeoff between minimizing the latency of non-time crit- ical messages and time-critical messages . . . . . . . . . . . . 7 1.4 The ob jective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.5 Thesis Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 CHAPTER 2 RELATED WORK . . . . . . . . . . . . . . . . . . . . . 10 2.1 Probabilistic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2 Deterministic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 CHAPTER 3 SYSTEM SETTINGS AND ASSUMPTIONS . . . . 16 3.1 Network topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.2 Node behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.3 Message transmitted in this network . . . . . . . . . . . . . . . . . . 17 CHAPTER 4 THE PROPOSED SEQUENCE DESIGN . . . . . . . 18 4.1 Basic rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 Proposed sequence design . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2.1 Where to start . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2.2 Where to end . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.3 The generalization of alignment of slot boundaries . . . . . . . . . . 24 CHAPTER 5 SIMULATION RESULTS . . . . . . . . . . . . . . . . . 27 5.1 Simulation parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.2 Simulation results and performance evaluation . . . . . . . . . . . . 29 5.2.1 Topology 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.2.2 Topology 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 CHAPTER 6 TEST BED . . . . . . . . . . . . . . . . . . . . . . . . . . 33 6.1 End nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 6.1.1 The packet format of hello messages . . . . . . . . . . . . . . 37 6.2 Sniffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 6.3 The Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 6.4 Evaluation of the end-to-end delay . . . . . . . . . . . . . . . . . . . 41 6.5 Evaluation of the power saving performance . . . . . . . . . . . . . . 42 CHAPTER 7 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . 449828709 bytesapplication/pdf論文公開時間：2014/09/03論文使用權限：同意有償授權(權利金給回饋學校)節電機器對機器網路非同步時間嚴格的訊息傳輸thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/264355/1/ntu-103-R01942113-1.pdf