Design of the Group Communication Protocol in VANET

[[abstract]]隨著無線網路的蓬勃發展，近幾年來車載行動網路也是無線網路技術中一直被討論的議題，不論在產業界或是學術界也都是被廣泛探討的議題之一。 車載行動網路本身是類似於傳統Ad-hoc網路的特殊型態， 但由於車載行動網路內主要成員是車輛，其移動相對較為頻繁且高速，但因道路特性之故不管是移動模式或者是移動速度等均有跡可循，不同於傳統Ad-hoc網路具有較大/多變異數。因此，Ad-hoc的尋找路徑方式並不太適合於車載行動網路。 本文探討車載行動網路環境下，針對使用者在車載行動網路上有著相同的特性和特殊動作，使之能設計出專用於這些使用者的群組通訊協定。以探討群組結構的維護及訊息的傳遞方式。本文提出一個方式以解決群組建立、群組分離與重組的演算法以及過程中傳輸路徑之維護機制。透過模擬分析的結果，所提出的車載群組通訊機制，不論在控制Control Message的增加、降低對RSU (Road Side Unit) 的負載等都有相當不錯的成效。[[abstract]]With the rapid development of wireless network, VANET has been discussed in recent year. It is also an important issue in industry and academia. VANET is similar to traditional Ad-hoc network. Since the major members of VANET are vehicles, which have highly moving characteristics, the mobility model and speed must obey the traffic rule. Therefore, the Ad-hoc routing protocol is not suitable for VANET. We design a group communication protocol for specific users to investigate route maintenance and data transmission, which have same mobility model and low relative speed in VANET. We propose Virtual VANET (VV) scheme which can solve the VANET problem such as group initialization, separation and route maintenance. As shown in performance evaluation, the Virtual VANET scheme reduces both control message and Road Side Unit (RSU) loading.[[note]]碩