車載通訊網路(Vehicular Ad-hoc Networks)可增加道路安全性並提供車輛存取網際網路的豐富資源。因為多數車載應用都有時限的問題，所以資料封包必須在時限到達之前將封包傳給目標車輛。然而，傳統作法一般使用泛流(Flood)的方式來傳輸資料，而其容易造成大量的封包碰撞，進而造成資料傳送的延遲時間增加。一筆封包通常不會只發送給一個目標。相對而言，群播(Multicast)更能有效率的發送資料給一個群體。然而，如何有效率的在時限之內將資料封包群播給目標群體，並達到最小的封包傳送次數，仍是學者探討的問題。基於成本考量，本論文提出一低成本之網路場景，並以此場景發展短訊群播機制，在一給定時間之內達到最少封包傳送次數。 Vehicular Ad Hoc Networks (VANETs) technologies can improve traffic safety for drivers and provide comfort services for passengers. Because most of the application in VANETs are time limited, so the data packets must be transmitted to target vehicles before the time limit exceeds. However, previous researches usually use Flood to transmit the data packets, which would easily cause a large number of packet collisions, and then lead to the increasing of delay time of the data packets. With the increasing of the users, more and more users would ask the same data. And Multicast would transmit data packets to a group of targets more efficiently. However, it is still a big problem that how we should efficiently transmit the data packets to a group of targets before the time limitation and achieve the minimum number of packet transmissions. Considering the cost, this paper proposed a low-cost network environment, and developed a short message multicasting mechanism with the achievement of minimum number of packet transmissions.
