由於近年來智慧交通系統蓬勃發展，無論是美國所祭出的專用短距離通訊技
術或者是歐洲所採用的蜂巢式車聯網，皆已提供相關的通訊協定，例如美國的
專用短距離通訊技術採用IEEE的802.11p通訊協定，而歐洲的蜂巢式車聯網則採
用3GPP Release 14/15/16通訊協定。由於美國所採用的專用短程距離通訊技術
已被實際應用於美國道路上，因此本篇文章將探討在專用短距離通訊技術下的
技術創新與應用。

在專用短距離通訊技術中，車輛通訊模式主要分為三類，(一)車輛對所有事
物(二)車輛對車輛(三)車輛對路側。依現行美國道路實驗，以第三種為主要測試
情境，因此本文考慮以第三種模式為車輛通訊通訊方法。

在傳統的車輛上，在行經高速公路時，僅能透過電子看板，以及手機應用程
式了解前方道路狀況，但當車輛遇見不可預期之事故，車輛無法接收到最即時
資訊，與無法即時決定是否改道，因此本文在高速公路上佈建路側單元，使其
廣播，並提供演算法。藉由演算法，決定是否靜態或者動態配置廣播資源給予
路側單元。若為動態配置廣播資源，則會依照路側單元佈建距離與整體廣播資
源量，在不同廣播時間，配置不同的廣播頻率。綜合靜態與動態的配置方法，
使在不同的佈建路段與不同的廣播資源情況下，皆可提升車輛接收率。最終，
佈建路段中所有車輛皆能即時接收最新訊息，並決定路徑安排，提升整體交通
效率。

Due to the rapid development of Intelligent Transportation Systems (ITS) in recent years, both Dedicated Short-Range Communication (DSRC) launched by the United States and Cellular Vehicle-to-Everything (C-V2X) adopted by Europe have provided relevant communication protocols, such as that DSRC adopted by the United States uses IEEE communication protocol, 802.11p, and C-V2X in Europe adopts the 3GPP Release 14/15/16 communication protocol. Since DSRC technology adopted by the United States has been actually applied to the roads, therefore, we explored the technological innovation and application under DSRC technology in this thesis.

In DSRC, vehicle communication modes are mainly divided into three categories: (1)Vehicle-to-Everything (V2X) (2)Vehicle-to-Vehicle (V2V) (3)Vehicle-to-Roadside (V2R). According to the current US road experiment, the third type is the main test scenario, so we used the third type of the modes as the vehicle communication method.

When people are driving traditional vehicles on the highway, they can check the road conditions through electronic billboards and mobile phone applications only. However, when unexpected events occur, this checking method prevents vehicles from receiving the most immediate information and cannot help humans to decide whether to change lanes in time. Therefore, we deployed roadside units (RSU) on highways to broadcast and provided an algorithm to allocate the frequency for each RSU in the thesis. Through the algorithm, the algorithm decides whether to statically or dynamically allocate broadcast resources to roadside units. If broadcast resources are dynamically allocated, broadcast time slots will be determined by the distance between RSUs in the deployment, and RSUs will be assigned the different broadcast resource according to different time slots. By combining non-dynamic and dynamic allocation methods, the algorithm can enhance the vehicular reception rate in different deployed sections and different broadcast resource situations, and finally all vehicles in deployment sections can receive the latest information in time and decide the arrangement of routes. The traffic efficiency can be improved.

Abstract (Chinese) I
Abstract II
Acknowledgements IV
Contents V
List of Figures VII
List of Tables VIII
List of Algorithms IX
1 Introduction 1
1.1 Background . . . . .1
1.2 Objectives . . . . . 3
1.3 Overview of Our System Architecture . . . . . 4
1.4 Our Contributions . . . . .5
2 Related Work 7
2.1 Vehicular Ad-Hoc Network . . . . . 7
2.2 Roadside Unit . . . . . 9
V
3 Network Simulator and Simulation of Urban Mobility 11
3.1 Overview of NS-3 . . . . . 11
3.2 NS-3 Architecture . . . . . 12
3.3 Example of NS-3 . . . . .12
3.4 Simulation of Urban Mobility . . . . . 13
4 System Architecture 16
4.1 Overview of Broadcast Rate Allocation Algorithm . . . . . 16
4.2 Broadcast Rate Allocation Algorithm . . . . . 17
4.3 Non-Dynamic Broadcast Rate Allocation Function . . . . . 19
4.4 Dynamic Broadcast Rate Allocation Function . . . . . 20
4.5 Our Algorithm Design Considerations . . . . . 23
5 Simulation Environment 28
6 Experimental Result 30
7 Conclusions 34
8 Future Work 36
Bibliography 38

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