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

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

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

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

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

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

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

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

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

PROBABILITY-BASED 2015/12/5 10

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

LOCATION-BASED 2015/12/5 12

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

NEIGHBOR-BASED 2015/12/5 14

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

CLUSTER-BASED 2015/12/5 16

SYSTEM ARCHITECTURE 2015/12/5 17

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

SYSTEM ARCHITECTURE 2015/12/5 19

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

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

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

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

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

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

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 /12/5 26

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

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.

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.

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