| 摘要: | 近年來隨著網路使用的多元化，網路的發展也從一般通訊產品延伸到車用通訊上，在車用網路的環境上，傳輸的品質也受大家注目，在這樣的發展上也越來越多人開始投入車用網路的運用，在車用隨用網路中(Vehicular Ad Hoc Network,簡稱VANET)包含了移動式車載及Road Side Units (RSU)，傳輸介面大致上分為三種: 其中之一為RVC(Road-vehicle Communication)，在此種模式中，車輛必須透過基地台(RSU 又稱 Infrastructure)才可相互溝通的傳輸，另外一種車輛間的溝通方式為IVC (Inter-vehicle Communication)，在此種模式下，車輛間的溝通無需透過RSU即可相互通訊。最後一種為混合型通訊(Hybrid of IVC and RVC)，在 VANET 中，混合型通訊是指同時結合 RVC 以及IVC兩
種無線通訊方式的傳輸方法。
由於車用的網路是以移動的傳輸方式，所以常常會遇到傳輸的訊號品質不好或是基地台不夠等問題，而產生每台車子在傳輸時會有封包碰撞問題，因此為了解決此問題我們提出來分散式排程演算法(Distributed Scheduling Algorithm, DSA)，利用車輛與基地台收訊品質、車輛的密集度、車速及資料量的大小，經由我們的演算法分析後選定最佳的車輛與RSU去做傳輸，解決傳輸封包碰撞問題，除了解決這個問題之外，在我們的研究中這個演算法的大小也會影響整個的網路效能，所以我們的進一步改善我們的演算法讓它更精簡化，去減少網路的負荷，以達到車載網路傳輸的最佳化品質需求。
With the high diversity of internet usage in recent years, the development of internet is expanded from daily communication products to the products for vehicular communication. People care about the signal transmission quality under the vehicular network construction. Based on this trend, more and more people start to engage in researching the application of vehicular network. The Vehicular Ad Hoc Network (VANET) includes mobile vehicular communication and Roadside Units (RSU). In general, the interface is divided into three categories: RVC (Road-vehicle Communication) is the first type. With this pattern, the signal is transmitted mutually through Road Site Unit, RSU (also called “infrastructure”). Another one is named of IVC (Inter-vehicle Communication), under such construction, the transmission between vehicles can do without infrastructure. The last one is Hybrid of IVC and RVC, in VANET it means the transmission method which combines the two wireless communication accesses, V2V and V2I.
Since the vehicular network is based on mobile transmission, we usually encounter some problems such as low signal quality and insufficiency of RSU, which might cause the package collision between vehicles during the transmission process. As a result, in order to solve the problem, we bring up the concept of Distributed Scheduling Algorithm, DSA. First we collect the information of the transmission quality between vehicles and RSU, the traffic flow, vehicle speed as well as the data volume. After our DSA analysis, we choose the best vehicles to do the transmission with RSU, which solves the problem of package collision. Except for solving this problem, the scale of DSA also affects the entire network utilization. Therefore, we make it more simplified to decrease the loading of the networks, which can optimize the vehicular network transmission. |
