VOL. 2, NO. 2, February 2012 ISSN ARPN Journal of Systems and Software AJSS Journal. All rights reserved

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1 Performance Analysis of AODV Routing Protocol In Vehicular Ad-hoc Network Service Discovery Architecture B. Ramakrishnan Associate Professor Department of Computer Science & Research Center, S.T Hindu College, Nagercoil-02 ABSTRACT VANET is the special type of MANET (Mobile Ad Hoc Networks) where the mobile nodes are vehicles that move on roads at very high speed following traffic rules; they provide communication between vehicle and vehicle (V2V) and Vehicle and Road side infrastructural unit (V 2 I). This paper explores the possibility of using VANET in inter vehicular communication. An attempt has been made earlier to create a new cluster model for efficient communication among the VANET nodes by the author [1]. A new clustering model has been created after taking the Simple Highway Vehicular model concept into consideration. This paper focuses the development of a clustering framework for data communication among the VANET nodes and the service discovery in Highway VANET model where the vehicles are moving outside the city. In the earlier study, the author of the paper [3] discussed the service discovery inside the city where more number of road side units are available and the communication between vehicle and vehicle (V2V) is established using road side unit only. But this paper discusses a service discovery architecture and data communication for vehicles outside the city where there is no road side unit (RSUs). Keywords: VANET, MANET, AODV, DSR, DSDV, SHWM, RSU, DRSC, GPS. 1. INTRODUCTION In VANET the mobility nodes are vehicles. The vehicle s movement varies with high speed or low speed. Unlike MANET, there are no power constraints for vehicles in a VANET and their network formation is dynamic. VANET is the important component of the Intelligent Transportation System (ITS) which provides the safety measures to passengers and drivers [2]. The movement of the vehicles is limited by the road condition such as narrow or curved. High speed vehicles form quick dynamic network topology and it requires real time packet transfer. These characteristics of VANET play an important role in creating a vehicular ad hoc network, new protocols and architectures. The vehicles are equipped with the Dedicated Short Range Communication (DRSC). These vehicles have the same transmission capability. The vehicles that move along the same road are able to communicate either directly to the destination or by using the intermediate node such as a router or the Roadside unit to transmit information and receive information [4]. 2. RELATED WORK The proposed system takes care of two scenarios Service Discovery when a vehicle moves inside the city [3] Service Discovery when a vehicle moves outside the city Roadside units are more in the city areas whereas they are less in outside city areas. When a vehicle enters a city area it directly sends the request to the road side units and gets the responses. When a vehicle enters outside city area, the vehicle does not get response from the Road Side Unit because of very limited or no roadside units are available outside the city. So a different architecture is required for data communication and service discovery procedure. This paper analyses the existing method as detailed in the ABSRP [3] and suggests a new method to solve the problem related to the (RSUs). A. Literature Survey The literature survey available on vehicular communication is very limited and most of them are the extension of the mobile ad-hoc networks (MANET). Most of the existing research works have been done on MANET. However, these cannot be directly applied to VANET as there is a fundamental difference between the architecture of VANET and MANET. [Luo Junhai et.al] and [Saxena et.al] have presented the architecture and standard for MANET which fail to model the characteristics of speedy Vehicles moving on highways with dynamic links that are quickly established and broken [5][6]. 65

2 B. Limitation with existing models Most of the existing VANET models are assumed as a collection of nodes (vehicles), links and fixed units called Roadside Units (RSU). Communication at any point is done from a VANET node to another VANET node through a Fixed Roadside Unit only [7]. This scenario is valid inside a city where the vehicle moves slowly and more number of fixed base stations is available. But if the vehicle moves with high speed on a highway outside the city, where there are a few or no roadside units, it is not possible to consider the city model of VANET. Hence it is necessary to propose a new model for VANET on a highway. The following section discusses the details of the proposed VANET Model. 3. SYSTEM MODEL In VANET each vehicle is equipped with a Global Positioning System (GPS) device to identify the correct location of the destination node [8][9]. Moreover, it is assumed that each vehicle has an on-board navigation system and the preloaded digital maps through which it can determine the position of its neighboring junction. It is also assumed that each vehicle has the knowledge about its velocity and direction of movement of the vehicle. The reliability of the routing protocols is analyzed only on the basis of the above mentioned assumptions. A. Proposed Simple Highway Mobility Model (SHWM) In this Model a Simple Highway is taken for characterizing the VANET. On a highway, vehicles can move freely on either direction. Each vehicle can have a limited radio range. Vehicle within a radio coverage range can communicate directly through a fixed roadside unit in the existing model. In this model no roadside units are available. 4. CLUSTER CREATION The Cluster creation in the proposed model is different from the existing model. In MANET, clusters are created dynamically but in the VANET the cluster area remains the same and predefined. A group of VANET nodes within a radio range can form a cluster area. In this architecture the VANET area has been split up into a number of clusters using the proposed cluster formation Algorithm 1. The size of the cluster changes only during unavoidable situations like sudden increase in the number of vehicles moving in a particular road due to traffic changes. In the new system the cluster remains in the same frequency. Unlike MANET, the VANET nodes move on predefined paths mostly on roads only. So the cluster areas are created as fixed ones. But, the cluster creation process involves a series of steps to ensure that the node created cluster is efficient and it gives better efficiency in service discovery[10][11]. Each cluster has a cluster head. The cluster head may be either RSU or any one of the vehicles with good database storage and access capabilities. This cluster head is selected by the new cluster head Algorithm 2. While creating the cluster, it should be ensured that the cluster head is not frequently crossing the cluster boundary. If the vehicle moves out frequently then the Cluster head election algorithm changes accordingly elects a new cluster head. A. CBVSOP: Cluster Based VANET Service Oriented Protocol Each cluster head carries all the service descriptions that are available in the network. All the cluster heads in the VANET are regularly updated if a new service enters the network. All the cluster heads are synchronized in a specific time interval. The cluster heads are so synchronized that they have the latest service descriptions. Nodes of the clusters are managed by service requests, service updates and latest service descriptions [12]. The cluster creation algorithm, cluster head election algorithm and cluster head switching algorithm were elaborately described by the author [1]. In the previous papers, the services of VANET are provided with the support of Road side unit. The road side unit acts as a router. In this paper, the VANET is approached in the form of clusters. This paper focuses on Service announcement, Service discovery and data communication in Vehicular ad- hoc network [13][14][15]. Algorithm 1: Cluster creation procedure 66

3 Algorithm 2: Cluster head Election. B. Service Announcement The exchange of information in the Service Announcement procedure takes place through the cluster heads. Only the cluster heads receive the service information and update their local database. If a new service is introduced, then all the cluster heads are immediately updated with the new information or data. If a node introduces a new service then it informs the local cluster head about it. The local cluster head multicasts the service description to all other cluster heads. The cluster head receives the service description and stores that in the local database. The service announcement procedure is shown in Algorithm 3. C. CBVSOP: Cluster Based VANET Service Oriented Protocol If a node in a cluster is in need of a service then it initially contacts its local Cluster head. The local cluster head searches it in the local database and ensures the specified service is available or not. If the specified service is present then it gives the necessary details about the service provider to the needed node to get the service. If the service is not present then the algorithm synchronizes all cluster heads in the VANET immediately. After synchronizing the procedure again it searches the cluster head for the availability of the required service. Again if the service is not present, it just informs the needed cluster service node that the service is not available. The CBVSOP procedure is shown in algorithm 4. D. Service Request Each individual node that requests one or more services initiates Service request. A service request packet consists of the following fields: < Packet-Type, Service-Description, Source Address, Route, Request ID, Lifetime, Max-Hops> Max-Hops field is set to limit the number of hops the request can travel. It helps us in regulating the extent to which a request package can reach and this can be used flexibly in different mobility situations. Route field is empty in the service request package. The pair of Source Address and Request-ID can be used to identify duplicate request. Service-Description field contains the type of service the client wants to discover in this process. Algorithm 3: Service Announcement Algorithm 67

4 Since the node is the service provider it matches the requirement of Service Request. The node will append its address to the field Route. Now the Route field contains a full route from Client to Service provider. And this packet will send back to the same reverse path of Route field. Cluster 2 Cluster 1 Service request Cluster 4 Head synchronization Cluster 3 Inter communication between head and node Communication between cluster heads Cluster head Service discovery architecture Service request service is not available in the local head then synchronize all the heads Service response Figure 1: VANET Service architecture Scenario Algorithm 4: CBVSOP Algorithm Table 1: Critical parameters used in NS 2.34 simulation < Packet-Type, Service-Description, Source Address, Route, Request ID, Lifetime, Hops Count> Algorithm 5: Service Request Algorithm E. AODV routing protocols Ad hoc routing protocol plays a very important role in VANET. Routing protocols are classified into Proactive Routing Protocol and Reactive routing protocols. Destination Sequence Distance Vector (DSDV) is a Proactive Routing Protocol; Reactive routing protocols are Dynamic Source Routing (DSR) and Ad-hoc On-demand Distance Vector Routing (AODV). Reactive 68

5 protocols are also known as on-demand routing protocols. Reactive protocols proceed for establishing routes to the destination only when a source vehicle wants to send a message to the destination [16][17]. 5. EXPERIMENTAL ANALYSIS The Cluster based simple highway mobility model is proposed and it has been simulated using NS 2.34 Version on Linux redhat 9 [18]. The following parameters are used in this test bed. VANET area is assumed as 1500*1500 meters of highway with bidirectional movement of Vehicles. Number of Nodes varies between 25 and 150. Number of Clusters varied between 2 and 20 in steps of 2. Speed of the vehicles is assumed to be constant between 5 m/s and 25 m/sec. The standard p, which is well suited for VANET communication is adapted in this scenario [19]. This paper analyses the performance of Throughput, Packet receiving time, Packet delivery ratio, Normalized routing load, Broadcasting time and Delay time for different nodes with various clusters and speeds. This paper also focuses the performance analysis of standard p over To enable reliability, for each category of result, the average of 50 samples has been included. 6. RESULT AND ANALYSIS The new standard p specifies a technology suitable for Vehicular Communication Networks. With this, a new operational Mode called Wireless Access in Vehicular Environment (WAVE) is defined to enable Communication among high speed vehicles or between vehicles and a roadside infrastructural network. The IEEE is currently working on the new standard p; an implemented version of IEEE standard is dedicated to Vehicular Communication. This standard specifies special implementation of the Medium Access Control (MAC) and Physical (PHY) layer of already existing standard This simulation has to be performed using realistic channel models and yields good performance p is currently being developed, which specifies physical (PHY) and Medium Access Control (MAC) protocol for car to car and car to infrastructural communication [20]. A. Packet receiving/delivery time of the Cluster based SHWM model with AODV and p The Figures 2,3,4 and 5 show the performance of packet receiving time for various cluster sizes with varying nodes between 25 and 150 and speeds 5m/s,10m/s,15m/s and 25m/s. From these graphs it is clearly identified that the number of nodes below 100 yields low packet delivery time. Figures 6 and 7 present the packet delivery time for various nodes with varying clusters from 2 to 20 with speeds 10m/s and 15m/s respectively. For speed 10m/s, low packet delivery time is received for Simple highway model with 4 clusters and the number of nodes below 100. Figure 8 shows the comparative analysis of packet delivery time for various speeds. From this graph it is noticed that low packet delivery time is achieved for low speed vehicles, B. Packet delivery ratio for the Cluster based SHWM model with AODV and p Figures 9 and 10 present the packet delivery ratio for various clusters with node speeds 5m/s and 25m/s. From this graph it is observed that the packet delivery ratio obtained for the cluster below 6 yields almost high value. When the number of clusters increases, the packet delivery ratio decreases. The packet delivery ratio is high for less number of clusters with speed 5. Figure 11 shows the packet delivery ratio for various speeds with AODV protocol. From this graph it is noticed that low packet delivery ratio is obtained for cluster below 6. The packet delivery ratio decreases when the speed of the vehicle increases. C. Analysis of service request/response procedure Figure 12 illustrates the performance of service reply time before synchronization of cluster heads and after synchronization of cluster heads in the cluster based simple highway model (SHWM). The service response time is very low for SHWM using AODV routing protocols before the synchronization of cluster heads. The Table 2 and 3 shows the service reply time value for before synchronization, after synchronization and service not available condition. Figure 2: Packet delivery time for various clusters with speed 5 69

6 Figure 3: Packet delivery time for various clusters with speed 10 Figure 6: Packet delivery time for various nodes with speed 10 Figure 4: Packet delivery time for various clusters with speed 15 Figure 7: Packet delivery time for various nodes with speed 15 Figure 5: Packet delivery time for various clusters with speed 25 Figure 8: Packet receiving time for various speeds using AODV 70

7 Figure 9: Packet delivery ratio for various clusters with speed 5 Figure 12: Service reply time for node 50 with speed 10m/s Table 2: Service reply time for 50 nodes with speed10 Clusters Reply Time Before Synchronization Reply Time After synchronization Reply Time Service Not Available Table 3: Service reply time for 50 nodes with speed25 Figure 10: Packet delivery ratio for various clusters with speed 25 Clusters Reply Time Before Syn Reply Time After Syn Reply Time Service Not Available Figure 11: Packet delivery ratio for various speeds using AODV 7. CONCLUSION This paper presents a cluster based Simple Highway Mobility model with Routing AODV. The VANET MAC layer standard p is used to measure Packet receiving time, Packet delivery ratio for various clusters with different nodes and speeds. In this paper the service discovery procedure is analyzed and the results are presented. Each VANET simulation has been done for 50 times and 50 various values are obtained for each node, cluster, speed, and p and the average value is computed and presented in this paper. The future work 71

8 would focus on finding different routing schemes for VANET node communications. Time taken to reach the information to all the nodes in this model is low. This model provides an efficient architecture for service request/response procedure. REFERENCES [1] B.Ramakrishnan,R.S.Rajesh,R.S.Shaji, CBVANET: A Cluster Based Vehicular Ad-hoc Network Model for Simple Highway Communication, Int.J.Advanced Networking and Application Dec-2010,Volume:02, Issue:04, page(s) : (2011). [2] Fan Bai Krishnan, Reliability Analysis of DSRC Wireless Communication for Vehicle Safety Applications, Intelligent Transportation Systems Conference, ITSC 06. IEEE Publication Year: 2006, page(s): [3] Berijesh Kadri Mohandas, Amiya Nayak, Kshirasagar Naik, Nishith Goel ABSRP:A Service Discovery Approach for Vehicular Ad-Hoc Networks page IEEE Asia Pacific Service Computing Conference [4] Lin Yang Jingdong Xu Gongyi Wu Jinhua Guo, Nankai Univ Tianjin, China Road Probing: RSU Assisted Data Collection in Vehicular Networks Wireless Communications, Networking and Mobile Computing, Beijing, page: 1-4 [5] Luo Junhai, Ye Danxia, Xue Liu, Fan Mingyu, A survey of multicast routing protocols for mobile Ad-Hoc network, Communications Surveys & Tutorials, IEEE Volume: 11, Issue:1, 2009, page(s): [6] Saxena, N., Tsudik, G., Jeong Hyun Yi, Polytech. Univ., Brooklyn, Efficient Node Admission and Certificateless Secure Communication in Short-Lived MANETs, Parallel and Distributed Systems, IEEE Transactions - Feb. 2009, Volume: 20 Issue: 2, page(s): [7] Wenmao LiuHongli Zhang, Weizhe Zhang, An autonomous road side infrastructure based system in secure VANETs Proceedings of the 5 th international conference on wireless communications, networking and mobile computing Beijing, China page(s): , IEEE [8] Shi, W., Liu Y Real-Time urban traffic monitoring with global positioning System equipped vehicles Intelligent Transport System, IET, Issue Date: June 2010, Volume 4, Issue 2, page (s): [9] A. Benslimane A. Bachir, Inter-Vehicle Geocast Protocol Supporting non equipped GPS vehicles, in Proc. Of Int. Conf. on Ad-Hoc, Mobile and Wireless Networks, Oct page(s) [10] Gunter, Y. Wiegel, B. Grossmann, H.P. Univ. Ulm, Ulm Medium Access Concept for VANETs Based on Clustering,Vehicular Technology IEEE Conference,2007 Page(s): , Baltimore. [11] Yuyi Luo Wei Zhang Yangqing Hu, Normal Univ., Shanghai, China A New Cluster Based Routing Protocol for VANET 2010 Second International Conference April 2010, Page(s): , Volume : 1 Wuhan, Hubei. [12] Sung-Han Lin Junn-Yen Hu, Cheng-Fu Chou, Ing-Chau Chang, Chien-Chun Hung A Novel Social Cluster-based P2P Framework for Integrating VANETs with the Internet page 1-9 IEEE April 2009 Proceedings. [13]Abrougui, K. Pazzi, R.W.N. Boukerche, A. PARADISE Res. Lab., SITE Univ. of Ottawa, Ottawa, ON, Canada Performance Evaluation of Location-Based Service Discovery Protocols for Vehicular Networks IEEE conference May2010, Page 1-5. [14]Coronado,E.S.Cherkaoui,S. Dept. of Electr. & Comput. Eng., Univ. of Sherbrooke, Sherbrooke, QC Service Discovery and Service Access in Wireless Vehicular Networks Globecom Workshops 2008 IEEE 2008, page 1-6 New Orleans, LO. [15] Boukerche, A. Abrougui, KSITE Univ. of Ottawa, Ottawa, ON, Canada A Service Discovery protocol for vehicular ad hoc networks: A proof of correctness Prallel and Distributed Processing,2009 IPDPS 2009,IEEE International Symposium May 2009, page 1-8. [16]Malik M. Ali Ibrahim Khan, Performance Analysis of Routing protocols for Vehicular Ad Hoc Networks Literature, April [17] Yuyi Luo Wei Zhang Yangqing Hu A New Cluster Based Routing Protocol for Vanet Networks Security wireless communication and trusted computing International Conference April 2010 Volume1 page: [18] Al-Mejibli, I. Colley, M. Evaluating transmission time of service discovery protocols by using NS2 simulator, Wireless Advanced (WiAD), th Conference on Publication -2010, page(s): 1 6. [19] Jiang, D. Delgrossi, L. Mercedes-Benz R&D North America, IEEE p: Towards an International Standard for Wireless Access in Vehicular Environments, Vehicular Technology Conference, May-2008, page(s): [20]L.Bononi M. Di Felice, A Cross Layered MAC and Clustering Scheme for efficient Broadcast in VANETs IEEE MASS 07 page 1-8,October 2007,Pisa, Italy. AUTHOR Dr. B. Ramakrishnan is currently working as Associate Professor in the Department of Computer Science in S.T. Hindu College, Nagercoil. He received his M.Sc degree from Madurai Kamaraj university, Madurai and received Mphil (Comp. Sc.) from Alagappa University Karikudi and PhD.(Comp.Sc.) from Manonmaniam sundaranar University, Thirunelveli. He has a teaching experience of 25 years. His research interests lie in the field of Vehicular networks, mobile networks and Ad-hoc networks. 72