1. 報告者 : 黃群凱 Inter-Vehicle Communication Protocols for Multimedia Transmission 出處 :Proceedings of the International MultiConference of Engineers and Computer Scientists 1

2. I. INTRODUCTION  Effective implementation of vehicular communication could also improve traffic management system.  vehicular communication networks not only could provide scalable connectivity between vehicles on the road but also can establish better coordination between road mobile users. 2

3. INTRODUCTION  This technology could improve traffic safety, driving assistance, entertainment, and mobile commerce.  Issues that have been investigated regarding VANET include mostly routing protocols for video streaming and simple text transmission, security problems, and suitable applications. 3

4. INTRODUCTION  The routing protocols in VANET are quite different from routing in mobile ad hoc network (MANET) due to several reasons including  high mobility.  frequent topology fragmentation.  frequent disconnection.  ample power requirements.  Therefore, routing protocols designed for VANET must be highly scalable, robust and easy to deploy. In addition, the frequent arrival and departure of vehicles brings many challenges in routing research. http://www.ifets.info/ 4

5. II. IVC PROTOCOLS FOR TEXT DISSEMINATION 5

6.  A. Broadcast Protocols  The objective of broadcasting in VANET is to disseminate information from one source to many destinations. In the other words, broadcasting is a method of information dissemination which is frequently used in VANET. 6

7. II. IVC PROTOCOLS FOR TEXT DISSEMINATION  B. Geocast Protocols  The objective of using geographic coordinates is to constrain the scope of message forwarding to a set of receivers  The node which receives an alarm message or warning should not rebroadcast it immediately but has to wait for some time, called defer time, to take a decision about rebroadcast.  Besides,in classical geocast routing, recently, abiding geocast is introduced to disseminate information to a group of nodes in an area for specific time interval as discussed in [16].  Two strategies are used to improve the efficiency of disseminating i.e. vehicles travelling in opposite direction are used as preferred relays to overcome fragmentation and reduce broadcasting. 7

8. II. IVC PROTOCOLS FOR TEXT DISSEMINATION 8  C. Unicast Protocols  Geographic unicast provides information delivery between two nodes via multiple wireless hops.  A position based routing consists of some components such as beaconing, location service, and forwarding scheme.  Beaconing is utilised to get topology information of the network.  The location service is used to obtain the location of the receivers.  The routing discovery strategy of position based forwarding algorithms based on location information.

9. III. VIDEO COMMUNICATION OVER VANET  在無線汽車網路的即時通信提供更全面的訊息，利用 通過多媒體，在災區內，視頻它可以幫助司機作出更 合適的決定。  有兩種方法視頻流在 VANET ：  （ 1 ）基礎設施的方法依賴基地台部署的存取點。  （ 2 ）基礎設施的方式轉發的視頻文件在附近區域的車輛。  第一種方法 ，基地台的部署與維護服務成本太高。 9

10. III. VIDEO COMMUNICATION OVER VANET  由於缺乏一個預裝的基礎架構設施，提供整個網絡的 集中控制。  無線技術和視頻壓縮技術的進步提供了一個實用的解 決方案通過 VANET 視頻流。  車輛嵌入大容量存儲能力，並提供高計算能力。 10

11. IV. IVC PROTOCOLS FOR VIDEO COMMUNICATION: A COMPARISON & DISCUSSION  Some authors [25] have discussed two routing protocols: Source Based Forwarding and Receiver Based Forwarding. The real video data are used to simulate video streaming over VANET  Authors [25] have changed the traffic density from sparse to dense. As a result, the quality of transmitted video is changed from bad to excellent as shown in Table 1.  Some authors [28] have proposed an adaptive Forward Error Correction (FEC) with interleaving technique to reduce the length of burst loss and retrieve from packet loss in VANET. 11

12. IV. IVC PROTOCOLS FOR VIDEO COMMUNICATION: A COMPARISON & DISCUSSION  這些實時應用的成就是不容易的，由於流動性高的車 輛和預現有的基礎設施不足。另一方面，視頻應用帶 寬，延遲和抖動性需求。 12

13. IV. IVC PROTOCOLS FOR VIDEO COMMUNICATION: A COMPARISON & DISCUSSION  在多媒體應用必須知道無線通道環境的誤差特性，動 態變化與時間和速度。  網絡編碼已成為替代傳統通信系統的路由算法。在這 種技術中，網絡節點可以結合他們所收到的數據包轉 發給下游節點之前。這種技術可以用來提高無線環境 中的視頻流的吞吐量。但是，它引入了一個解碼延遲。 因此，調查吞吐量和解碼延遲之間的權衡，仍然是一 個開放的研究問題。 13

14. V. CONCLUSION  The comparison results conclude that for multimedia applications, this critical environment could negatively affect the performance of the network.  All these changes must be synchronised with the software and hardware environment for the efficient control and improvement. 14