1. Hop State Prediction Method using Distance Differential of RSSI on VANET 指導教授：許子衡 教授 學 生：董藝興 學生 1

2. Introduction In VANET, each hops can dynamically move and it can move at high speed. So, the optimized routing protocol is required in VANET. 2

3. Introduction By using the speed, using RSSI a distance, and the factors, this protocol predicts the link destruction possibility of the in- between hop. By finding the first the amount of change, and the second the amount of change the range change that it is periodic can be found. 3

4. Introduction It is the proactive protocol which it makes the new link before a link is destroyed by this prediction and prevents the link break down. If the Proactive protocol is not used, a communication is unable to be smoothly made while the new link is produced after a link is destroyed. 4

5. Related works However, in VANET, the network disconnection is the main factor of the emergency message propagation time delay and network connectivity degradation. Therefore, the excel routing protocol is required. 5

6. Related works The major focus of VANET : Safety and non-safety applications Roadside-to-vehicle and vehicle-to-vehicle communication Communication protocol design Channel modeling Modulation and coding Power control and scalability issues 6

7. Related works Multi-channel organization and operation Security issues and countermeasures Privacy issues Network management Simulation frameworks & real-world testbeds 7

8. Related works Reactive Routing Protocols in VANET : Traditionally, reactive protocols do not take into account mobility parameters during route discovery, resulting in paths which often break in highly mobile scenarios such as VANETs, causing excessive broadcasting and flooding the entire network in order for new routes to be discovered. 8

9. Related works Furthermore, the additional initial latency introduced by the route-discovery procedure poses serious challenges for reactive protocols. 9

10. Related works Proactive Routing Protocols : In proactive Routing Protocols (PRPs), the flip-side of reactive protocols, maintain and update information on routing between all nodes of a given network at all times. Route updates are periodically performed regardless of network load, bandwidth constraints, and network size. 10

11. Related works Hybrid routing protocols : Hybrid routing protocols combine both the proactive and reactive approaches. Zone routing protocol (ZRP) is a notable example. 11

12. Related works To avoid link rupture during data transmission, a movement-prediction-based routing (MOPR) is proposed in [13]. MOPR predicts future positions of vehicles and estimates the time needed for the transmission of data to decide whether a route is likely to be broken or not during the transmission time. 12

13. Related works The performance of the scheme largely depends on the prediction accuracy and the estimate of the transmission time that depends, in turn, on several factors such as network congestion status, driver’s behavior, and the used transmission protocols. 13

14. Related works In [14], a distributed movement-based routing algorithm is proposed for VANETs. This algorithm exploits the position and direction of movement of vehicles. The metric used in this protocol is a linear combination of the number of hops and a target functional, which can independently be calculated by each node. 14

15. Proposed method The method to be proposed uses the RSSI (Received Signal Strength Indication) of the signal occurred in a vehicle and we predict the link break down. 15

16. Proposed method 16

17. Proposed method 17

18. Conclusion This proposal predicts the possibility yes or no whether by using the RSSI value, it finds out a distance and velocity information and the pertinent node can maintain a link or not. This prediction used first differential, second differential of distance difference for link maintenance. 18

19. Conclusion By establishing the new link in case of predicting with the breakage of a link it is bitter and a throughput is increased and the packet drop is ordered with reduction. 19