車輛駕駛在高速公路上行駛時，需要隨時掌握道路路況，以提前進行路線規劃或是避開發生車禍意外的地點。現在的車輛駕駛主要是依賴道路上電子看板訊息及利用手機應用程式的通知來得知路況消息，然而往往因為訊息的不足、通知接收不即時以及資訊解讀不易，進而錯失變更路線的時機。

車載隨意網路（VANET, Vehicular Ad Hoc Network）是一種行動通訊技術，將車輛與交通設施當成節點，並且透過無線通訊技術形成行動網路。本研究以車載隨意網路為研究背景，探討在車載隨意網路中路側元件（RSU, Road-side Unit）佈建方式的接收率最佳化，以使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，進而提升整體交通效率。

本研究在特定廣播時間內，透過分析不同的佈建方式，會讓不同行駛距離的車輛通過不同數量的路側元件之特性，建立出整數規劃模型，再將車輛數據放進整數規劃模型得出最佳解，接著使用NS-3和SUMO進行網路模擬來驗證最佳解。

經數據模擬結果得出路段頭尾佈建方式能使佈建路段中成功即時接收訊息之車輛數最大化，為接收率最高之佈建方式。本研究預期能夠更有效地解決高速公路上車輛在緊急情況下的資訊傳遞問題，以提高道路安全性和通行效率，為未來的交通管理和設施優化提供重要參考依據。

Vehicular Ad-Hoc Networks (VANETs) have emerged as a key component of Intelligent Transportation Systems (ITS), garnering significant research interest in recent years. VANETs enable several communication mechanisms, including Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), and Vehicle-to-Everything (V2X). The Road-Side Unit (RSU) is a fixed infrastructure installed along roads to facilitate communication between vehicles and the network infrastructure. Proper RSU deployment is vital for enhancing the performance of VANETs.

This thesis focuses on a highway scenario with two intersections separated by a distance, where vehicles travel from one side to the other. The objective is to maximize the overall reception rate at which vehicles receive broadcasts by strategically deploying a limited number of RSUs between the intersections. The highway was divided into segments, and traffic flow was analyzed in each segment. An integer programming problem was formulated and the optimal RSU deployment solution was obtained using a mathematical model.

The research results demonstrated that deploying RSUs at the two ends of the highway segment, a strategy referred to as "Head-Tail," could significantly increase the number of vehicles receiving broadcasts compared to other strategies such as uniform or concentrated deployment. This finding highlights the importance of strategically deploying RSUs to achieve high overall reception rate, a crucial metric for VANET applications.

Abstract (Chinese) I
Acknowledgements (Chinese) II
Abstract III
Contents IV
List of Figures VI
List of Tables VII
1 Introduction 1
2 Related Work 3
2.1 Vehicular Ad-Hoc Network 4
2.2 Roadside Unit (RSU) 5
2.3 RSU Deployment 7
3 System Model and Problem Formulation 11
4 Network Simulation 15
4.1 NS-3 15
4.2 Simulation of Urban Mobility 18
5 Simulation Environment and SetUp 20
6 Simulation Results and Discussion 23
7 Conclusions 29
Bibliography 31

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