1. Cluster-Based Multi-Channel Communications Protocols in Vehicle Ad Hoc Networks IEEE Wireless Communications october2006, vol.13 No. 5 指導老師：童曉儒 教授 報告人：張益瑞 2015/12/5 1

2. Outline INTRODUCTION SYSTEM ARCHITECTURE FUNCTIONS AND DESIGNS OF PROTOCOLS THE CLUSTER CONFIGURATION PROTOCOL THE INTRACLUSTER COORDINATION AND COMMUNICATION PROTOCOL SIMULATION EVALUATIONS CONCLUSIONS 2015/12/5 2

3. INTRODUCTION(1/2) What is DSRC(Dedicated Short Range Communication)? V2V-based VANETs and V2R-based VANETs. The data transmitted over the VANETs can be classified into the real-time traffic and the non- real-time traffic. 2015/12/5 3

4. DSRC DSRC/802.11p The standard of 802.11p is based on IEEE 802.11a PHY layer and IEEE 802.11 MAC layer Seven 10 MHz channels at 5.9GHz one control channel and six service channels 2015/12/5 4

5. V2V-BASED VANETS AND V2R-BASED VANETS 2015/12/5 5

6. THE DATA TRANSMITTED OVER THE VANETS real-time traffic such as safety messages and video/audio signals non-real-time traffic such as e-maps and road/vehicle- traffic/weather information 2015/12/5 6

7. INTRODUCTION(2/2) Our proposed scheme mainly consists of following three core protocols. Cluster Configuration Protocol Intracluster Coordination and Communication Protocol Intercluster Communication Protocol 2015/12/5 7

8. SYSTEM ARCHITECTURE Four Broadcasting Strategies 1. Probability-based 2. Location-based 3. Neighbor-based 4. Cluster-based 2015/12/5 8

9. FOUR BROADCASTING STRATEGIES 1. Probability-based: A given PDF determines the decision, for example depending on the number of copies a node has received. The strategy is often dynamic. PDF = probability distribution function 2015/12/5 9

10. PROBABILITY-BASED 2015/12/5 10

11. FOUR BROADCASTING STRATEGIES Location-based The selection criterion is the amount of additional area that would be covered by enabling a node to forward. Some proposal also computes position prediction as useful input information. 2015/12/5 11

12. LOCATION-BASED 2015/12/5 12

13. FOUR BROADCASTING STRATEGIES Neighbor-based A node is selected depending on its neighbors status (for instance, the status concerns how a neighbor is connected to the network). 2015/12/5 13

14. NEIGHBOR-BASED 2015/12/5 14

15. FOUR BROADCASTING STRATEGIES Cluster-based Nodes are grouped in clusters represented by an elected cluster-head. Only cluster-heads forward packets. Nodes in the same cluster share some features (e.g., relative speed in VANETs). Reclustering on-demand or periodically. 2015/12/5 15

16. CLUSTER-BASED 2015/12/5 16

17. SYSTEM ARCHITECTURE 2015/12/5 17

18. SYSTEM ARCHITECTURE Our proposed scheme handles the following three tasks Cluster-membership management Real-time traffic (such as safety messages delivery) Non-real-time data communications (such as e-maps download, movies download, etc.) 2015/12/5 18

19. SYSTEM ARCHITECTURE 2015/12/5 19

20. 有限狀態機 ( FINITE STATE MACHINE, FSM) 在現實中，有許多事情可以用有限個狀態來表達。 紅綠燈運作的原理相當簡單，從一開始綠燈，經過一 段時間後，將變為黃燈，再隔一會兒，就會變成紅燈， 如此不斷反覆。 2015/12/5 20

21. FUNCTIONS AND DESIGNS OF PROTOCOLS We use the Finite State Machine (FSM) Each vehicle operates under one and only one of the following four states at any given time: cluster-head (CH) quasi-cluster-head (QCH) cluster-member (CM) quasi-cluster-member (QCM) 2015/12/5 21

22. FUNCTIONS AND DESIGNS OF PROTOCOLS 2015/12/5 22 Finite state machine of our proposed scheme. T1 and T2 represent Transceiver 1 and Transceiver 2

23. THE INTRACLUSTER COORDINATION AND COMMUNICATION PROTOCOL 2015/12/5 23 Time division in the CRC channel

24. THE INTRACLUSTER COORDINATION AND COMMUNICATION PROTOCOL 2015/12/5 24 T t = 分時多工時間區段 N = 叢集內群組成員 gap = 平均車間距離 v = 平均車輛長度 L c = 半徑 N lane = 位於公路上的車道數量

25. THE INTRACLUSTER COORDINATION AND COMMUNICATION PROTOCOL 2015/12/5 25 T = repetition period( 重複期間，預設為 200ms) R = channel rate T safety = 更新安全訊息的間隔時間 H safety = 安全訊息的 packet size ，預設為 200bytes

26. SIMULATION EVALUATIONS 實驗情境設定 環境：單向 3 線道 進入時間： 2100 秒，變異數： 180 秒 平均速率： 35m/s ，變異數： 15m 2 / s 2 2015/12/5 26

27. SIMULATION EVALUATIONS 實驗工具： Matlab 參數設定： 車距： 25m 車長： 5m 車內半徑： 150m 車間半徑： 400ms 接收時間： 150ms 發送時間： 50ms 安全訊息封包大小： 200bytes 2015/12/5 27

28. SIMULATION EVALUATIONS 2015/12/5 28 The performance of three protocols against non-real-time traffic arrival rate: a) Probability of safety-message-delivery failure; and b) aggregate throughput of non-real-time traffics. The size of the non-real-time traffic packet is 512 bytes.

29. SIMULATION EVALUATIONS 2015/12/5 29 Channel busy rates of the seven different channels. The size of the non-real-time traffic packet is 512 bytes and the packet arrival rate of the non real-time traffic is 200packets/sec/vehicle.

30. CONCLUSIONS Reduce data-congestion Support QoS for real-time delivery of safety messages High throughput 2015/12/5 30