智慧型運輸系統(Intelligent Transportation Systems, ITS)是一運用先進技術，整合電腦、電子及通訊技術用以提昇運輸效率之系統，ITS內可分為車輛基礎設施整合(Vehicle-Infrastructure Integration, VII)和車間通訊(Inter-Vehicle Communication, IVC)兩部份。VII之部份著重在車輛與路側設施之訊息傳輸，而IVC則著重在車輛間彼此之訊息傳輸。其中VII與IVC兩者於道路上之通訊網路是以Ad-Hoc無線網路點對點傳輸模式為基礎所形成，而由道路上之車輛彼此傳遞即時交通資訊所形成之網路稱為 (Vehicular Ad-Hoc Network , VANET)。

本研究主要目的是提出一整合模擬架構，以探討VANET車用網路之相關課題，而本整合模擬架是車流模擬與網路模擬之間建立起一資訊回饋介面，其中車流模擬由中觀車流模擬器DynaTAIWAN (Dynamic Traffic Assignment and Information in Wide Area Networks)進行，而網路模擬由微觀網路模擬器NS2(Network Simulation version 2)所進行。此整合模擬架構之目的是為模擬VANET車用網路對於車流之影響，在此整合模擬架構下，網路模擬之資料將回饋至車流模擬，當車流模擬器接收到網路模擬回饋之資訊後，運用IVC車間通訊之車輛將依據所收到之訊息調整旅行路徑。

本研究進行離線型及線上型之實驗，以說明整合模擬架構之效能及其如何進行VANET車用網路之研究，其中離線型實驗主要探討不同之速度、密度之車流，及不同之通訊傳輸距離對VANET車用網路效能之影響，由離線型實驗可知封包遞送率會隨著車流密度高時而下降。

本研究於線上型實驗中討論資訊回饋間隔對於整合模擬架構模擬VANET效能之影響，由線上型實驗結果可知整合模擬器之資訊回饋間隔，需設計成符合車流模擬器之中觀特性。

Intelligent Transportation Systems (ITS) focus on increasing the efficiency of existing surface transportation systems through the use of advanced computers, electronics, and communication technologies. Two types of communications are important in ITS, namely Vehicle-Infrastructure Integration (VII) and Inter-Vehicle Communication (IVC). VII focuses on the communication between vehicles and infrastructures and IVC focuses on the communication between vehicles and vehicles. The wireless communication network for vehicles in traffic networks based on VII and IVC is named Vehicular Ad-Hoc Network (VANET).

This research proposes an integrated simulation framework for simulating VANET. The integrated framework establishes a feedback interface between two simulation components, traffic simulation and communication simulation. The traffic simulation is performed through DynaTAIWAN, a mesocopic simulation-assignment model, and the communication is simulated through Network Simulation version 2 (NS2). This framework is constructed to study the traffic impact of VANET. Within the framework, the information from network simulation is feedback to traffic simulation. When the traffic simulator receives the information from network simulator, the IVC vehicles can change route based on received information.

Offline and online experiments are conducted to illustrate the proposed framework and possible benefits from VANET. The offline experiments are conducted to study possible impact of density and speed of vehicular flows and communication range. The results show that packet delivery rate decreases with respect to traffic density.

The on-line experiments focus on the impact of information feedback interval on the performance of VANET. The results from the online experiments show that information feedback interval should be designed carefully in apply VANET in a traffic network.

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