Improved Communication Reliability Considering Data Flow in RPL-based IoT
Improved Communication Reliability Considering Data Flow in RPL-based IoT
- 주제(키워드) IoT , RPL , TSCH , Autonomous Scheduling , Convergecast , Routing , Performance
- 발행기관 아주대학교 일반대학원
- 지도교수 김기형
- 발행년도 2018
- 학위수여년월 2018. 8
- 학위명 박사
- 학과 및 전공 일반대학원 컴퓨터공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000027838
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Internet of Things (IoT) refers the technology for connecting resource constrained devices around us to the Internet via wireless networks. Through the application of IP technology to communications between devices, IoT is expanding its application area to a wide range of applications in various environments. Communication reliability in IoT networks is an important factor for reliable low-power data transmission. Through the guarantee of communication reliability in the IoT network, the application field of IoT can be expanded to various fields such as the emergency service, beyond the application field of the existing wireless sensor network. In order to improve the reliability of data communication in the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) based IoT, a different approach is needed depending on the characteristics of the data flow. For the data collection, we focus on TSCH with RPL. We research the timeslot scheduling algorithm for TSCH using routing path of RPL to achieve the goal of ensuring the reliable data and the low end-to-end delay. In addition, RPL provides two optional modes for downward routing, these two modes have advantages and disadvantages that conflict with each other, and the disadvantages of these two modes are weak points when consisting large-scale networks. Therefore, in order to improve the reliability of data communication, the downward routing of RPL needs to be improved. In this dissertation, we propose novel algorithms to improve communication reliability considering characteristics of data communication flow in RPL-based IoT networks. Firstly, we propose a scheduling scheme, named Escalator, optimized for the data collection based on the routing topology generated by RPL in a TSCH based network. Escalator provides a slotframe schedule for a network in which all nodes can send packets to the sink in every slotframe cycle, regardless of the network topology. Secondly, we propose a hybrid downward routing mode to improve the reliability of downward packet transmission in RPL based networks. The proposed hybrid mode stores a routing information by distributing the information to a DODAG root and routers. Then, the proposed hybrid mode provided a solution for the scalability issue occurred from resource limitation of routers in the storing mode as well as the increase in the fragmentation stemming from routing overheads in the non-storing mode. We implement the proposed algorithms and evaluate their performance with existing schemes through a testbed and simulation. The experimental results show that the proposed algorithms have lower end-to-end delay and higher packet delivery ratio compared to the existing schemes. We also discuss future works.
more목차
Abstract ⅰ
Contents ⅲ
List of Figures ⅵ
List of Tables ⅷ
Abbreviation ⅸ
CHAPTER 1
Introduction 1
1.1. Background and Statement of the Problem 1
1.2. Dissertation Objective 4
1.3. Dissertation Contribution 5
1.4. Dissertation Organization 6
CHAPTER 2
An Autonomous Scheduling Scheme for Convergecast in TSCH 7
2.1. Introduction 7
2.2. Preliminaries 11
2.3. Related Work 14
2.3.1. Scheduling of WSNs based on TDMA and Channel Hopping 14
2.3.2. Timeslot Scheduling for Convergecast 18
2.4. Proposed Autonomous Scheduling Scheme for Convergecast 20
2.4.1. Timeslot Allocation Mechanism 24
2.4.2. Sliding Slotframe Mechanism 27
2.4.3. Channel Offset Selection Mechanism 29
2.4.4. Baseline Slotframe Size Determination 34
2.5. Analysis of Escalator 40
2.5.1. Conflict Definition 40
2.5.2. Proof of the Conflict-Freeness of Convergecast Schedule 41
2.5.3. Analysis of Scheduling Scheme 44
CHAPTER 3
A Hybrid Mode to Enhance the Downward Route Performance in RPL 48
3.1. Introduction 48
3.2. Preliminaries 52
3.3. Problems of Two Modes of RPL Downward Routing 57
3.4. Proposed Hybrid Operation Mode 61
3.4.1. Routing Information Management 61
3.4.2. RPL Hop Extension Header 63
3.4.3. The Operation of Downward Packet Transmission in Proposed Hybrid Mode 65
3.4.4. Comparison with the Existing Downward Routing Modes 68
CHAPTER 4
Evaluation 71
4.1. Evaluation for Escalator 71
4.2. Simulation Environment for Hybrid Operation Mode in RPL 75
CHAPTER 5
Performance Analysis 79
5.1. Performance Analysis of Escalator 79
5.1.1. Performance Metric 79
5.1.2. Testbed Results 80
5.1.3. Simulation Results 82
5.2. Performance Analysis of Hybrid Operation Mode in RPL 88
5.2.1. Routing Table Size 88
5.2.2. Packet Delivery Ratio 90
5.2.3. End-to-End Delay 94
CHAPTER 6
Conclusions and Further Studies 96
References 99
