時至今日，城市的大眾運輸系統已經有良好的發展，藉由完整的都市規劃，公車路線會妥善的分布到城市中重要的建築周圍。公車網路為車載網路的延伸應用，它是以城市的大眾運輸系統為骨架。藉由在公車與公車站上裝設無線路由，提供服務給城市的民眾與移動的車輛。公車網路有著強烈的耐延遲網路特性，因為公車移動速度較慢並且公車在城市中的密度低。根據先前研究，公車網路的通訊方式主要分為三種，分別為公車對公車通訊、公車對公車站通訊、公車輔助通訊。本論文研究公車對公車站通訊，因為先前研究的實驗結果得出公車對公車站通訊的表現比公車對公車通訊更加良好。我們的目標是要利用公車對公車通訊在最短的時間將資料送給移動中的車輛，藉由實驗結果探討公車網路的可行度。我們以指數分布產生公車的移動軌跡，藉此模擬公車實際可能發生的誤點，並在公車會誤點的情形測試方法的效能。最後實驗結果顯示，公車網路的效能容易受到公車間隔的影響，但是在適當的公車間隔下，藉由增加candidate path size，還是可以得到可接受的效能。最後總結公車網路以輔助車載網路的角度來看，仍是一個不錯的選擇。

Recently, the public transportation system of a city in Taiwan has been well developed, the bus lines are well distributed over important buildings by the comprehensive city planning. Bus network is an extension of VANET with the backbone which is based on public transportation systems. By installing wireless devices on buses and bus stops, we can serve most of vehicles and people in city by WIFI-enable buses and stops. Bus network has strong characteristics of delay-tolerant network due to the slow driving speed of buses and the low density of buses in city. In previous approaches, there are three types of ways to route data in bus network: bus-bus, bus-stop and bus-assisted. In previous studies, the performance of bus-stop is better than bus-bus, hence we choose bus-stop to route data in bus network. Our goal is to route data to the moving vehicles in the shortest time by bus-stop routing method, and the feasibility of bus network will be discussed. We generate the trajectories of buses with exponential distribution, and exploit those trajectories to simulate the actual arrival time of buses with unexpected traffic conditions. The results have shown that the performance of bus network is strongly affected by the intervals between buses, but we can reach acceptable results under an appropriate bus interval by increasing candidate path size. In the conclusion, bus network is an appropriate way to assist VANET.

1. 前言 1
2. 文獻回顧 10
2.1公車對公車的通訊（Bus-to-Bus） 10
2.2公車對公車站的通訊（Bus-to-Stop） 12
2.3公車輔助通訊（Bus-Assisted） 17
3. 系統模型 21
4. 方法 23
4.1公車站sλ的滿足條件 24
4.2建立路徑 ps 25
4.3改善封包傳送成功率 30
5. 實驗模擬 32
5.1情境一（公車間隔固定下觀察4種candidate path size的表現）34
5.2情境二（公車間隔呈指數分布下4種candidate path size的表現）38
5.3情境三（公車間隔為固定，在candidate path size為3，3種無線傳送成功率的表現）40
5.4情境四（公車間隔呈指數分布，在candidate path size為3，3種無線傳送成功率的表現）42
6. 結論與未來展望 43
參考文獻 45
附錄 46

[1]” An Efficient Routing Protocol in a Bus-based Vehicular Ad hoc Network , “From 2010 First International Conference on Pervasive Computing, Signal Processing and Applications
[2]” Routing in Large-Scale Buses Ad Hoc Networks , “From Wireless Communications and Networking Conference, 2008. WCNC 2008.
[3]”Position-Based DTN Routing in Metropolitan Bus Network,” From 2012 International Conference on Systems and Informatics （ICSAI 2012）
[4]”Timely Data Delivery in a Realistic Bus Network, ” IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, 2012
[5]” Bus Assisted Connectionless Routing Protocol for Metropolitan VANET , “From 2011 Fifth International Conference on Genetic and Evolutionary Computing
[6]” The IG-Ferry Protocol to Support Efficient Controlled Replication in Vehicular Delay Tolerant Network, ” From 2012 9th International Conference on Ubiquitous Intelligence and Computing and 9th International Conference on Autonomic
and Trusted Computing
[7] 沈龍利（2010）。大眾運輸規劃 : 理論與實務。台北市 : 秀威資訊科技。